Extracellular matrix: new insights into its role in female reproductive aging and potential therapeutic strategies.

ECM proteins are emerging as quantitative biomarkers of systemic aging, yet their tissue-specific dynamics within the female reproductive tract remain under-characterized. Ovarian and uterine aging are accompanied by measurable shifts in the matrisome, collagen cross-linking, elastin fragmentation, and hyaluronan remodeling that precede overt follicle loss or endometrial dysfunction 59 , 60 . Since these alterations are detectable by low-invasive imaging or fluid proteomics 61 , 62 , ECM signatures offer a new decision-making layer for clinicians managing declining ovarian reserve or implantation failure. In the following sections, we dissect how age-dependent ECM remodeling impinges on ovarian and uterine aging, and discuss how these insights are being translated into biomarker algorithms and therapeutic targets. Age-related decline in fertility is still attributed to a decrease in gamete quantity and quality, but current research is increasingly focusing on the ovarian microenvironment, given that the microenvironment can modulate gamete quantity and quality 63 . The dynamic reciprocity between ovarian cells and the ECM is crucial for tissue homeostasis and disease development. Understanding ECM changes during aging provides a basis for future anti-aging strategies 64 (Fig. 1 ). Fig. 1 Age-related ECM remodeling in the ovary disrupts follicle development and fertilization. Aging exerts significant impacts on the ovary and ovarian follicles, as well as the subsequent fertilization process. In the ovary, aging induces increased fibrosis and inflammation, reduced hyaluronic acid (HA) levels, and elevated tissue stiffness. At the follicle level, aging results in a thinner cumulus cell layer, enlarged intercellular space, and a smoother zona pellucida (ZP). The purple arrow denotes the progression from the young (lower left, healthy) to the aged (upper right, fibrotic and inflamed) ovarian state. During follicle development, aging leads to a decreased ovulation count and impaired oocyte quality, accompanied by increased ovarian stiffness. Activation of the Hippo signaling pathway (Hippo ON) is involved in this process, which may impede follicular progression, as indicated by blocked arrows and red crosses representing inhibited processes. For fertilization, aging-associated alterations in cumulus cells and the ZP hinder sperm interaction and penetration, as illustrated by the red cross indicating a block in fertilization. ECM Extracellular matrix, HA Hyaluronic acid. Created with BioRender.com. Aging exerts significant impacts on the ovary and ovarian follicles, as well as the subsequent fertilization process. In the ovary, aging induces increased fibrosis and inflammation, reduced hyaluronic acid (HA) levels, and elevated tissue stiffness. At the follicle level, aging results in a thinner cumulus cell layer, enlarged intercellular space, and a smoother zona pellucida (ZP). The purple arrow denotes the progression from the young (lower left, healthy) to the aged (upper right, fibrotic and inflamed) ovarian state. During follicle development, aging leads to a decreased ovulation count and impaired oocyte quality, accompanied by increased ovarian stiffness. Activation of the Hippo signaling pathway (Hippo ON) is involved in this process, which may impede follicular progression, as indicated by blocked arrows and red crosses representing inhibited processes. For fertilization, aging-associated alterations in cumulus cells and the ZP hinder sperm interaction and penetration, as illustrated by the red cross indicating a block in fertilization. ECM Extracellular matrix, HA Hyaluronic acid. Created with BioRender.com. The ovaries experience substantial changes throughout the female lifetime. Ouni et al. 59 described the dynamic changes in the ovarian ECM from prepuberty to menopause, using ovarian cortical samples from women of different ages, including composition and mechanical properties. Collagen is central to the ovarian ECM, and its remodeling is a key feature of ovarian aging. While studies in mice show progressive, age-related collagen deposition leading to overt stromal fibrosis 65 , human ovarian tissue reveals a more nuanced picture. Polarized light microscopy of human samples indicates that the proportion of thick collagen fibers peaks specifically during the reproductive years, though remaining a minor component, <7% of total collagen. This transient, structured remodeling is likely estrogen-mediated and may facilitate folliculogenesis, contrasting with the later-life, inflammation-associated fibrotic microenvironment observed in both aging mice and humans 66 . Furthermore, the age-dependent thickening of the ovarian tunica albuginea in transgender patients has been attributed to fibrosis in the sub-albuginea cortical region 67 . Beyond histological evidence from Sirius Red staining, proteomics and single-cell sequencing data of ovaries and reproductive tracts from aged mice have further confirmed the characteristics of fibrosis and revealed the inflammation associated with fibrosis 14 , 68 . During aging, the levels of the inflammasome NLRP3, along with other inflammatory mediators such as TNF-α, IL-6, and TGF-β3, are elevated in the ovarian stroma, follicular fluid, and peripheral blood 69 – 71 . Meanwhile, immune cell subsets in aging ovaries undergo dynamic changes, particularly among macrophages and B cells. For instance, macrophages exhibit a shift towards an alternatively activated (M2-like) phenotype and show inconsistent changes in abundance across studies, while B cell numbers vary and are not consistently increased. Additionally, T cell composition is also altered, with notable accumulations in double-negative T cells, especially type 1 and type 17 innate-like lymphocytes prior to reproductive failure 68 , 72 . Notably, a unique population of multinucleated giant cells derived from macrophages may serve as a potential biomarker of ovarian aging-related inflammation 70 , 73 , 74 . Overall, age-related ovarian collagen deposition and pro-inflammatory fibrotic characteristics have emerged as major features of ovarian aging. HA, a key glycosaminoglycan (GAG), exhibits age-related alterations that disrupt oocyte maturation and compromise the ovarian microenvironment. GAGs are a class of negatively charged polysaccharides that form the hydrated gel of the ECM and are crucial for tissue structure and cellular communication 75 . Ouni et al. 66 reported that GAGs accumulate in human ovaries with age. However, Amargant et al. 76 observed a decline in total HA content, suggesting complex alterations in HA during aging. Furthermore, in mammalian ovaries such as those of pigs and cattle, HA levels exhibit notable species-specific differences. Porcine ovaries contain significantly higher HA levels than bovine ovaries, and HA in both ovarian tissue and follicular fluid displays distinct molecular weight distribution patterns (300 kDa), further indicating that HA composition may be closely related to the reproductive physiological characteristics of different species 77 . Moreover, the zona pellucida (ZP), a specialized ovarian ECM, is a structure that directly envelops the surface of the oocyte. It is composed of glycoproteins such as ZP1, ZP2, ZP3, and ZP4, as well as components like HA 78 . Yu et al. observed that, compared to young mice, the ZP of middle-aged mice exhibited a smoother texture, accompanied by a reduction in transzonal projections from the surrounding cumulus cells 79 . Other age-related changes in ovarian ECM components, such as elastin, EMILIN-1, and fibrillin-1, are closely associated with female fertility by influencing the mechanical compliance of the ovarian stroma, thereby regulating follicle activation, growth, and the permissive microenvironment necessary for ovulation and oocyte development 66 . Proteomics and spatial transcriptomics data further confirm the age-related changes in ovarian stromal proteins, establishing these alterations as new hallmarks of ovarian aging 80 , 81 . Collectively, these molecular changes drive alterations in the mechanical properties of the ECM. Overall, ovarian stiffness in mammals increases with age 76 , with aging ovaries exhibiting more pronounced differences in stress relaxation rates between the cortex and medulla 82 . Ovaries in reproductive-age women demonstrate the lowest stiffness, the smoothest surface morphology, and the most compact fiber arrangement compared to prepubertal and menopausal ovaries 13 . These findings highlight a strong correlation between ovarian mechanical properties and female fertility. Supporting this notion, Grosbois et al. cultured ovarian cortical tissue in vitro and found that collagen content in the cortex decreases with follicular development, while elastin increases at the cortical-medullary junction. These findings indicate that the ovarian ECM microenvironment is region-specific and dynamically regulated by follicle development, highlighting its crucial role in folliculogenesis 83 . Notably, emerging clinical imaging techniques such as shear-wave elastography offer a non-invasive means to quantify ovarian stiffness in vivo, potentially serving as a biomarker for assessing ovarian aging and predicting reproductive outcomes 62 , 84 . To understand the functional consequences of ovarian ECM age-related changes, it is crucial to elucidate its mechanistic links to fertility decline. The following discussion will, therefore, dissect these mechanisms in the context of follicle development, ovulation, and fertilization, with the ultimate aim of informing potential therapeutic strategies to restore fertility. Aging-related alterations in the ovarian ECM impede normal follicle development and compromise oocyte quality. Ovarian stiffness acts as a key regulatory signal alongside hormonal cues, with the rigid cortex maintaining primordial follicles in dormancy. The role of ovarian mechanical forces and signaling in follicular development is thoroughly discussed in Fiorentino’s work. During the ovulatory cycle, follicles migrate to the softer medulla, exiting dormancy and completing maturation in the peri-medullary region before ovulation at the ovarian surface. This process is primarily governed by the Hippo and Akt signaling pathways, which are essential for organ shape and size maintenance 85 , 86 . In the aging ovary, ECM stiffening sustains Hippo pathway activation and attenuates Akt signaling, thereby suppressing normal follicular activation pathways. Meanwhile, the progressively deteriorating microenvironment characterized by fibrosis, vascular dysfunction, and inflammation accelerates the depletion of the primordial follicle pool via mechanisms such as aberrant activation followed by atresia or direct follicular degeneration, ultimately leading to diminished ovarian reserve 85 , 87 . Novel therapeutic strategies, such as drug-free in vitro activation and whole-ovary laparoscopic incision, have shown promising clinical outcomes in patients with diminished ovarian reserve (DOR) due to aging or other factors. These approaches significantly enhance follicular hormonal responsiveness, improve pre-ovulatory follicle and oocyte quality, and increase both natural and assisted pregnancy rates. Their mechanisms likely involve the disruption of ovarian Hippo signaling, as well as hypoxia and fibrosis pathways, further underscoring the critical role of mechanical signals in follicular development 88 – 91 . Furthermore, Pietroforte’s research has demonstrated that follicles cultured in high-stiffness environments exhibit decreased survival and growth, with reduced estradiol synthesis in granulosa cells and diminished oocyte quality. These findings align with West et al.’s 92 work on alginate hydrogels, in which stiff matrices were shown to suppress follicle expansion, antrum formation, and theca cell differentiation, and reduce oocyte meiotic competence. Genes associated with follicle development are downregulated, while those related to inflammation and ECM remodeling are upregulated 93 . Additionally, declining HA levels in human follicular fluid have been associated with failed embryo implantation. Specifically, women diagnosed with infertility due to endocrine dysfunction have been shown to exhibit significantly lower follicular fluid HA levels compared to those with other infertility causes, such as male factor 94 . Moreover, as expected, HA levels show a gradual decline with increasing maternal age 95 . This suggests that reduced HA production in aging ovaries may impair embryo implantation. Cumulus expansion is vital for female fertility. By forming a hydrated HA-rich matrix, it physically protects the oocyte, guides sperm for fertilization, and facilitates fimbrial capture at ovulation 96 , 97 . In murine models of ovarian aging, this process is impaired. Defective expansion is linked to reduced HA levels and loss of matrix structural integrity, providing a direct mechanistic explanation for age-related infertility 95 . In other tissues, low-molecular-weight HA (LMW-HA) accumulates with the aging process. Based on this, it is hypothesized that the same occurs in aging ovaries. In vitro experiments have demonstrated that bioactive LMW-HA fragments may drive an inflammatory matrix environment via eosinophils and directly impair gamete quality by compromising granulosa cell function, thereby contributing to reproductive aging 98 . Ovulation is the process by which a mature follicle ruptures, releasing the oocyte, along with its surrounding cumulus cells, onto the ovarian surface. Fertilization, in contrast, refers to the process in which a sperm penetrates the ZP of the ovulated oocyte and fuses with the oocyte to form a zygote. Both processes are critically regulated by the cumulus cell-oocyte complex (COC) matrix. Chen’s study experimentally revealed the extremely low Young’s modulus, nonlinear elastic behavior, and mechanical heterogeneity of the COC matrix, including a hyaluronan-rich cell-free layer up to 200 μm in thickness. The softness and elasticity of the COC matrix are thought to play pivotal roles in oocyte transport through the fallopian tube, as well as in sperm penetration and selection 99 , 100 . Notably, Yu et al. observed that the age-related decline in fertilization rate is not attributed to the oocyte itself, but rather to structural and compositional alterations in the ZP. In middle-aged mice, the ZP displays increased smoothness, loss of its characteristic mesh-like structure, increased thickness and total surface area, as well as a higher proportion of internal fibrous components, thereby preventing sperm binding. These ZP modifications primarily serve as morphological markers of an aged follicular microenvironment, which is rooted in age-impaired cumulus-oocyte communication and compromised cytoplasmic maturation of the oocyte. While ZP changes directly undermine fertilization, the underlying ovarian aging that they reflect may also reduce ovulation efficiency and diminish the developmental potential of ovulated oocytes, collectively contributing to fertility decline 79 , 101 . Ovulation represents a dynamic process involving both tissue injury and repair. Jamie N. Mara et al. 102 demonstrated that in reproductively aged mice, the number of ovulated oocytes and corpora lutea decreases, with more oocytes and expanded COCs trapped within the corpora lutea, leading to ovulation failure. This phenomenon is likely driven by age-related ovarian fibrosis and increased tissue stiffness, which physically constrain follicular rupture. Consistent with this, histologic analysis reveals elevated collagen deposition (particularly around corpora lutea) in aged ovaries compared to young controls. Furthermore, post-ovulatory repair mechanisms are impaired with aging, as evidenced by reduced luteal vascularization, altered ECM composition (including increased collagen and decreased HA), diminished cellular turnover, impaired wound closure, and aberrant morphology of ovarian surface epithelium 102 . These multifaceted impairments in post-ovulatory repair may collectively drive a self-reinforcing fibrotic cycle, resembling the classic pathological process in which aberrant tissue repair promotes fibrosis 103 , 104 . Research on female reproductive aging has traditionally focused on ovarian decline. However, clinical evidence indicates that even with restored ovarian function and embryo quality through interventions like hormone replacement, embryo transfer, or oocyte donation, older women still face uterine-factor fertility challenges, including reduced endometrial receptivity and low live birth rates 7 , 105 . This highlights the need to consider the underrecognized independent aging mechanisms of the uterine microenvironment. The uterus, a highly dynamic organ, undergoes monthly cycles of endometrial shedding and regeneration during the reproductive years 106 . In advanced maternal age, the decline in endometrial receptivity represents a major determinant of adverse pregnancy outcomes 107 . This decline is associated with alterations at the molecular, cellular, and histological levels, including aberrant hormonal responses, impaired decidualization, collagen deposition, and vascular dysfunction 108 . Uterine aging is further driven by cellular senescence, chronic inflammation, and epigenetic dysregulation, which contribute to implantation failure, increased miscarriage rates, and reduced pregnancy maintenance 109 . Moreover, genetic, metabolic, and immunological perturbations are integral to this aging process. For example, genomic studies indicate an age-related accumulation of somatic mutations in endometrial glands 110 , while integrated omics approaches highlight associated metabolic dysregulation, exemplified by overactive mTOR signaling 111 , 112 , and a chronic inflammatory state within the aging uterine environment 113 . These perturbations, along with the aforementioned mechanisms, can be systematically dissected through multi-omics technologies, which provide valuable insights into the molecular underpinnings of uterine aging and its impact on reproductive function 114 . The ECM, acting as a physical and biochemical scaffold, plays a critical role in regulating endometrial regeneration, embryo implantation, and stem cell niche maintenance through dynamic remodeling 114 – 117 . Disruptions in ECM homeostasis are strongly associated with age-related reproductive disorders. (Fig. 2 ). Fig. 2 Age-related ECM remodeling in the uteri disrupts decidualization and embryo implantation. The figure compares young and aged uteri, illustrating age-related changes and their impacts on embryo implantation. In the aged uterus, there is a reduction in elastic fibers with increased fragmentation, enhanced collagen deposition leading to higher tissue stiffness, rupture of elastic fibers in vascular wall, elevated levels of advanced glycation end products (AGEs), and decreased expression of matrix metalloproteinases (MMPs). These structural and molecular alterations disrupt key processes required for successful embryo implantation, leading to four major impairments: (1) Impaired decidualization, as indicated by blocked cellular interactions and reduced MMP activity. Age-related ECM stiffening and diminished MMP activity hinder the differentiation of endometrial stromal cells into decidual stromal cells. Labels denote endometrial stromal cells (left), collagen-rich ECM environment, downregulated MMP activity (yellow), and blocked differentiation into decidual stromal cells (right). (2) Immune imbalance, characterized by disrupted T-cell migration and altered interactions between T cells, AGEs, and collagen. (3) Abnormal vascular remodeling, associated with disorganized collagen and elastic fiber networks. (4) Trophoblast invasion disorder, driven by increased tissue stiffness and a shift in collagen composition from collagen IV to collagen I. AGEs Advanced glycation end products, MMP Matrix metalloproteinase. Created with BioRender.com. The figure compares young and aged uteri, illustrating age-related changes and their impacts on embryo implantation. In the aged uterus, there is a reduction in elastic fibers with increased fragmentation, enhanced collagen deposition leading to higher tissue stiffness, rupture of elastic fibers in vascular wall, elevated levels of advanced glycation end products (AGEs), and decreased expression of matrix metalloproteinases (MMPs). These structural and molecular alterations disrupt key processes required for successful embryo implantation, leading to four major impairments: (1) Impaired decidualization, as indicated by blocked cellular interactions and reduced MMP activity. Age-related ECM stiffening and diminished MMP activity hinder the differentiation of endometrial stromal cells into decidual stromal cells. Labels denote endometrial stromal cells (left), collagen-rich ECM environment, downregulated MMP activity (yellow), and blocked differentiation into decidual stromal cells (right). (2) Immune imbalance, characterized by disrupted T-cell migration and altered interactions between T cells, AGEs, and collagen. (3) Abnormal vascular remodeling, associated with disorganized collagen and elastic fiber networks. (4) Trophoblast invasion disorder, driven by increased tissue stiffness and a shift in collagen composition from collagen IV to collagen I. AGEs Advanced glycation end products, MMP Matrix metalloproteinase. Created with BioRender.com. The average uterine volume is 38.55 ± 3.68 cm³ in individuals aged 17–19 years, peaking at 71.76 ± 19.81 cm³ between 35 and 40 years of age 118 . During the premenopausal phase of reproductive aging, the uterus undergoes significant region-specific alterations in ECM composition, mechanical properties, and biomechanical behavior. Specifically, the myometrium exhibits biphasic mechanical changes, with initial softening followed by stiffening, whereas the cervix undergoes progressive age-related hardening 119 , 120 . These alterations are critically determined by the content and structural organization of ECM components, particularly collagen and elastin, and are closely associated with declined myometrial contractile function and related parturition impairments in advanced maternal age, such as prolonged labor 119 , 121 . The passive mechanical properties of the uterine wall (myometrium) also display a biphasic change with advancing age. Biaxial inflation testing showed that in mice, as reproductive age increased from 2–3 to 10–12 months, the linear modulus and toe modulus of uterine tissue decreased significantly, indicating enhanced tissue compliance. In contrast, in the aged group (20–24 months), both moduli increased, signifying elevated tissue stiffness 119 . This stiffening phenomenon may be linked to increased elastin and collagen content. Raman spectroscopy confirmed this finding, revealing significantly higher spectral intensities for elastin and collagen in the aged group (20–24 months), thereby further establishing the association between biomechanical characteristics and uterine aging 119 . Concurrently, aging similarly impairs the active contractile function of the uterus. In aged individuals, the spontaneous contractile force of the myometrium and its responsiveness to stimulatory cues are significantly reduced. For example, the spontaneous contractile force of the myometrium in young rats was threefold greater than in aged rats; young myometrium spontaneously reaches its maximal contractile potential, whereas aged myometrium requires external stimulation to achieve comparable contractile levels 121 . Microarray analysis further demonstrated that maternal age regulates the expression of genes involved in key pathways, including immune response, inflammation, lipid metabolism, steroid metabolism, tissue remodeling, and smooth muscle contraction 121 . Collectively, these alterations in biomechanical properties provide crucial insights into the potential mechanisms underlying prolonged labor duration and dysfunctional labor in advanced maternal age. In contrast to the myometrium, the cervix, a primary load-bearing structure during pregnancy, exhibits a distinct aging pattern characterized by progressive collagen accumulation and stiffening. Its tensile strength is largely derived from its high collagen content. Analysis of human cervical biopsy samples revealed an average collagen concentration of 62.2%, which showed a positive correlation with age (0.5% annual increase, r  = 0.45). Maximum load was positively correlated with collagen content (mg/mm), and normalized maximum stiffness increased with age ( r  = 0.32) 120 . In the C57BL/6 J mouse model, the extended gestation period and prolonged labor duration associated with advanced maternal age may be linked to altered extensibility of cervical tissue in older mice 122 . Furthermore, hydroxyproline content (a collagen marker) was significantly higher in cervical tissue from premenopausal women compared to postmenopausal women, a difference potentially linked to the disappearance of the squamocolumnar junction region after menopause 123 . Studies also indicate that the apparent elastic modulus of the uterosacral ligaments decreases with age, reflecting a reduced capacity to resist deformation. This increased tissue compliance and laxity compromise the structural support of pelvic organs, thereby elevating the risk of pelvic organ prolapse 124 . These age-related alterations in uterine biomechanical properties are intrinsically linked to profound remodeling within the ECM. Specifically, changes in the abundance, organization, and molecular characteristics of key structural components, such as collagen and elastin fibers, underlie these mechanical adaptations during reproductive aging. The region-specific biomechanical changes are fundamentally driven by profound ECM remodeling, with dysregulated collagen deposition being a central feature. Single-cell RNA sequencing of the murine reproductive tract reveals a marked age-related increase in fibrosis-associated gene expression (e.g., Col1a1), consistent with Sirius Red staining showing accelerated uterine collagen deposition (3.2% area increase per 6 months, padj < 10 −4 ). Fibroblast pathways involved in ECM organization and inflammation are significantly enriched 60 . Immunohistochemical analysis of human tissues further confirms thicker collagen fibers in the mucosal stroma of aged uterine tubes 125 . Collagen degradation slows with age, potentially due to increased crosslinking and structural modifications, declining further postmenopause likely due to hormonal shifts 126 . Conversely, long-term estrogen administration promotes stromal fibrous-hyaline deposition in a dose- and duration-dependent manner 127 . Increased collagen is also evident in aged rodent uteri, particularly within endometrial stroma and smooth muscle 128 , and elevated levels of denatured cervical collagen compromise function in aged cows 129 . Aging profoundly alters collagen mobility and solubility decline, while AGEs accumulate, inhibiting fiber assembly. Spectroscopic analyses confirm structural deterioration, including lower scattering spectra indicating assembly loss, increased network heterogeneity and reduced density, and strengthened carbohydrate signals relative to total protein, reflecting AGEs accumulation 130 . During pregnancy, the progressive increase in uterine blood flow is primarily accommodated by uterine arterial remodeling, with decidual vascular remodeling as a pivotal component 131 . This stage-specific process involves early degradation of key ECM components (collagen IV, laminin), followed by later infiltration of placental endovascular trophoblasts and increased deposition of fibronectin and fibrinogen 132 . However, in advanced maternal age pregnancies, ECM changes, characterized by accumulated aged collagen, reduced elastin, and an elevated collagen/elastin ratio, diminishes vascular compliance and uterine perfusion 133 . Furthermore, the aging ECM, enriched with degradation products and inflammatory factors, combined with oxidative stress, compromises nitric oxide (NO) bioavailability, impairing NO-mediated vasodilation and blood nutrient supply 134 . These alterations disrupt vascular cell proliferation, hindering normal remodeling. Decidualization comprises a series of complex and orderly physiological changes in the endometrium during early pregnancy, which are crucial for successful embryo implantation and maintaining pregnancy. Normally, endometrial stromal cells secrete various matrix metalloproteinases (MMPs) during decidualization. These enzymes degrade the ECM and release growth factors, promoting cell proliferation and differentiation 135 . However, in aged endometrium, collagen fiber degradation is impaired, and ECM accumulates, creating a fibrotic environment that suppresses MMP activity. This prevents effective ECM breakdown, hindering decidual cell migration and expansion. Moreover, fibrotic endometrium often involves inflammatory cell infiltration and cytokine release, which disrupts the decidualization-related cytokine network, interfering with normal decidualization initiation and maintenance 107 . Studies also indicate that in fibrotic endometrium, the expression of TGF-β superfamily members is upregulated. TGF-β plays a role in both fibrosis and decidualization. While it regulates decidualization-related gene expression via the Smad signaling pathway, excessive TGF-β signaling can lead to abnormal decidualization 135 . During embryo implantation, trophoblast cells exhibit behaviors similar to those of tumor cells, including attachment, invasion, differentiation, and fusion 136 . They interact with cells in the decidual stroma and secrete MMPs to degrade the ECM 137 . These fused placental syncytiotrophoblast cells are responsible for nutrient exchange between the mother and fetus, supporting embryonic development and maintaining pregnancy. Changes in the composition and mechanical properties of disease-specific ECM affect trophoblast cell behavior. Studies have shown that in preeclampsia, type IV collagen, which is normally present, is replaced by type I collagen, significantly reducing the fusion efficiency of trophoblast cells 138 . Similarly, in a diabetic rat model, localized fibronectin deposition within the placental labyrinth region alters the microenvironment at the maternal-fetal interface and leads to developmental abnormalities in offspring 139 . Further underscoring the functional importance of the ECM, Natale et al. 140 demonstrated that specific ECM components, laminin, fibronectin, and type IV collagen, regulate the maintenance and differentiation of mouse trophoblast stem cells, either preserving their undifferentiated state or promoting lineage-specific specialization. Furthermore, the mechanical properties of ECM, such as surface thickness and stiffness, regulate trophoblast cells self-assembly, proliferation, invasion, and gene expression. Using in vitro Matrigel and type I collagen models, research has found that thicker Matrigel surfaces induce trophoblast cells to self-assemble into 3D spheres, which exhibit thickness-dependent changes in viability, proliferation, syncytial fusion, and gene expression profiles compared to two-dimensional cultures. This suggests that the response to surface thickness may be partially mediated by cellular stiffness-sensing mechanisms 141 . Therefore, in the aged endometrium, abnormal changes in the composition and mechanical properties of ECM, including the ratio of type I and III collagen, might affect the biological behavior of trophoblast cells. Additionally, age-related increases in hydroxylated albumin in the endometrium reduce the ability of extravillous trophoblasts to adhere to and invade collagen ECM pretreated with carbonylated albumin 142 . Collectively, the composition and mechanical properties of the aged endometrial ECM undergo senescence-like changes, affecting trophoblast cell proliferation, invasion, and fusion, leading to syncytiotrophoblast fusion disorders and subsequently hindering embryo implantation. The maternal-fetal interface presents a unique immunological paradox, requiring a delicate balance between tolerating the semi-allogeneic fetus and establishing robust antimicrobial defenses 143 . This balance can be disrupted by various factors regulating immune cells at the interface, potentially leading to pregnancy failure. Among these factors, alterations in the ECM have been shown to significantly affect the phenotype and function of immune cells. Exogenous addition of type I collagen can modulate the Th17/Treg imbalance, reduce embryo resorption rates, reshape the immune microenvironment, and improve fertility in RSA mouse models 144 . Furthermore, the accumulation of advanced AGEs during the aging process continuously disrupts the maternal immune tolerance state. Haucke et al. showed that AGE-modified matrix proteins inhibited the migration and adhesion of Jurkat T cells 145 . Additionally, IgG is an important antibody that provides anti-infectious protection during the neonatal period, and glycosylation of the Fc region of IgG can regulate the cytotoxicity of natural killer (NK) cells against syncytiotrophoblasts and the production of cytokines. Another key immunomodulator, sialylated Glycodelin A, promotes the differentiation of monocytes into decidual macrophages via interaction with Siglec-7, thereby regulating maternal-fetal immune tolerance. Abnormal glycosylation can disrupt these processes 146 . Collectively, abnormal glycosylation and the accumulation of AGEs in the aging uterus could affect ECM cross-linking and disrupt maternal-fetal immune tolerance, leading to pregnancy failure.

The primary components of the ECM include collagen, elastin, proteoglycans, and various growth factors, along with connecting elements such as laminin and fibronectin 15 . The complete repertoire of ECM and ECM-associated proteins that a cell or organism can express is called the ‘Matrisome’ 16 . In various tissues, the composition and assembly of the ECM vary, resulting in distinct structural and functional characteristics that facilitate specialized functions 17 . For example, tendons, rich in collagen I and elastin, are designed to withstand multidirectional forces and efficiently transmit muscular force to the skeletal system 18 . Conversely, perineuronal nets in the brain, consisting of hyaluronic acid (HA), proteoglycans, and tenascin, are structured to enhance neurogenesis 19 . Beyond providing structural support, the ECM actively regulates cellular behaviors such as survival, proliferation, migration, and differentiation through multiple mechanisms. The ECM exerts its influence on cells vi a specific surface receptors, including integrins, discoidin domain receptors, and the hyaluronan receptor CD44 20 – 22 . Recent studies have also demonstrated that mechanosensitive ion channels, such as Piezo1, can transduce ECM mechanical signals into intracellular chemical signals, thereby affecting gene expression and epigenetic modifications 23 – 25 . Additionally, the ECM acts as a reservoir of growth factors, modulating the abundance of various growth factors and their receptors 26 . Continuous ECM signaling governs cellular functions by modulating genomic, epigenetic, and metabolic pathways 27 – 30 . Thus, the intricate interactions between the cells and ECM are fundamental to tissue homeostasis. Alterations in the composition and structural integrity of the ECM can result in the development of various pathologies 31 – 33 . For instance, a recent study from Stanford University demonstrated that alterations in the viscoelastic properties of the ECM in liver of patients with type 2 diabetes promotes the development of liver cancer 34 . Similarly, changes in ECM content, such as excessive collagen deposition, can lead to organ fibrosis 31 . Both mechanical properties and compositional changes of the ECM play crucial roles in the onset and progression of diseases. With the rapid advancement of omics technologies, proteomic data of tissue-specific ECM can identify potential biomarkers for disease occurrence, diagnosis, and prognosis. Furthermore, these data can help uncover key targets in the underlying mechanisms of disease development 35 – 37 .

Organoids derived from the ECM are 3D cell culture models built by mimicking the structure and function of the ECM. Their application in the reproductive system is of great significance, providing a powerful tool for studying reproductive physiology, disease mechanisms, and developing new therapies. Research has shown that endometrial organoids can simulate the epithelial phenotype and pathological biology of the endometrium, including the in vitro reproduction of the menstrual cycle, offering a more accurate model for studying endometrium-related diseases 181 . Similarly, the embryo implantation model, by developing apical-out endometrial organoids, has successfully simulated key stages of embryo implantation, providing a new perspective for understanding this mechanism. In the context of intrauterine adhesions, tissue-engineered uterine constructs using a bilayer scaffold have been shown to promote the regeneration of both the endometrium and smooth muscle, offering a novel strategy for uterine repair 182 . Ovarian organoids can simulate the cellular heterogeneity and functional characteristics of the ovary, aiding in the study of ovarian physiology and pathology 183 . These advances demonstrate the great potential of ECM-derived organoids in simulating the function of reproductive organs, studying disease mechanisms, and developing new therapies. With continuous technological advancements, these models are expected to play an increasingly important role in the field of reproductive medicine. Building on these foundations, the integration of microfluidic technology further revolutionizes reproductive research. Microfluidic chips now enable the recapitulation of the female reproductive system, including the ovaries, fallopian tubes, uterus, placenta, and cervix. These systems support 3-D dynamic culture of follicles and oocytes, allow high precision sperm selection and handling, facilitate real-time monitoring of embryonic development, and automate the addition and removal of cryoprotectants, thereby significantly enhancing the success rates of in vitro fertilization and assisted reproductive technology. Furthermore, chips also model endometriosis, fibroids, ovarian, endometrial, and cervical cancers, offering platforms to study disease and screen drugs. By linking multiple organs and sensors in one circuit, the same devices monitor hormones, drug transfer across the placenta, and maternal-fetal interactions, supporting personalized reproductive health and safer pregnancy 184 . Organoids grown on 3-D ECM scaffolds replicate the architecture and hormonal cycles of the ovary, endometrium, and placenta, providing faithful models for studying reproductive physiology, disease, and drug response. Meanwhile, microfluidic chips miniaturize these organs into perfused microchannels that support dynamic follicle-oocyte culture, precise gamete and embryo manipulation, multi-organ communication, and real-time monitoring 185 . Integrating the two platforms enables high-throughput screening of compounds for their impact on ovarian reserve, endometrial thickness, and implantation, allowing rapid identification of molecules that restore follicular activity, reverse endometrial atrophy, or prolong luteal function. Furthermore, patient-derived “aging-on-a-chip” systems further dissect single-cell mechanisms of reproductive decline and, within the same circuit, test reprogramming factors or anti-aging agents, offering a unified strategy to delay or reverse female reproductive aging 186 .

This review synthesizes current understanding of the dynamic remodeling of the ECM within reproductive tissues and its pivotal role in female reproductive aging. Accumulating evidence demonstrates that ECM functions not merely as a static scaffold, but rather as an active signaling network that participates in cell fate determination. With advancing age, the composition, structure, and physical properties of ECM in reproductive tissues undergo significant remodeling. These age-related changes include excessive collagen deposition and cross-linking, leading to tissue fibrosis, elastin degradation, and alterations in matrix stiffness. Through mechanotransduction pathways mediated by integrins and other receptors, these ECM modifications regulate key reproductive processes such as folliculogenesis, ovulation, decidualization, and embryo implantation, ultimately contributing to the development of DOR and age-related infertility. However, research in this field still faces significant limitations. Firstly, current studies on ECM in reproductive aging have primarily focused on the ovary 187 . Due to the influence of the menstrual cycle and the unique regenerative properties of the endometrium 188 , investigating uterine ECM is more challenging, and there is a lack of comprehensive omics data characterizing the ECM changes in the aging uterus 107 . Such data could provide new insights into research on pregnancy-related disorders in advanced maternal age 189 . Secondly, while ECM acts as both a “biochemical signal hub” and a “mechanosensory platform” 190 , the types of signaling that contribute to fertility decline during reproductive aging remain poorly defined. Clarifying this distinction is crucial for guiding the development of targeted interventions against ECM aging. Thirdly, the molecular mechanisms linking ECM aging to reproductive decline remain insufficiently explored. Future studies should employ cell-specific knockout mouse models and tunable hydrogel-based 3D culture systems (allowing precise manipulation of ECM stiffness and ligand density) to directly test whether specific ECM alterations are sufficient to drive reproductive cell senescence and to elucidate the downstream signaling pathways involved 141 , 191 . Finally, particular attention should be given to how ECM aging in non-reproductive tissues (e.g., hypothalamus and adipose tissue) affects reproductive function through systemic factors such as the secretome 192 . Meanwhile, leveraging machine learning to analyze ECM degradation products (e.g., specific collagen fragments) in serum or follicular fluid offers a promising approach for developing predictive models. This could lead to novel non-invasive biomarkers for assessing reproductive aging and ovarian decline, holding significant clinical translational value 193 . Given the unique material properties and excellent biocompatibility of ECM, current research has extensively explored its value in tissue regeneration, immune regulation, and as a stem cell carrier. In reproductive medicine, for instance, multiple studies have shown that Endo/Whole-UdECM hydrogel derived from pig uterus can significantly promote the regeneration of thin endometrium, restore embryo implantation capacity, and improve fertility rates by modulating the IGF1/IGFBP3 signaling axis and reshaping uterine NK cell subsets 175 . However, these groundbreaking studies remain largely confined to animal experiments and early clinical validation, facing critical challenges such as medical ethics and the immunogenicity of xenogeneic materials. Future research is expected to achieve breakthroughs in the following directions. A key priority is the systematic evaluation of the immunocompatibility and functional differences among ECMs from different species (e.g., pig, bovine, human) to establish standardized safety assessment systems. Furthermore, further investigation is needed into the molecular mechanisms by which the ECM acts as an anti-aging target, rather than merely serving as a passive vehicle for stem cell delivery. Recent studies suggest that young ECM can reverse follicular apoptosis by regulating signaling pathways such as PTEN/PI3K-Akt via miRNAs (e.g., miR-21-5p), providing new insights for developing ECM-based “microenvironment rejuvenation” strategies 151 .

The study of ECM changes during aging and their impact on tissue and organ function has garnered significant attention. The turnover and modification of ECM are critical in reproductive aging, and their abnormal changes can adversely affect the growth, differentiation, and functional maintenance of reproductive cells 60 , 66 , 81 . In response, several anti-aging strategies targeting ECM remodeling have been developed. The initial phase aims to degrade aberrant ECM deposits to restore a more youthful tissue state 147 . Driven by progress in decellularization techniques, decellularized ECM can be processed to create advanced biological scaffolds. These scaffolds recapitulate the three-dimensional structure and mechanical properties of the ECM in young reproductive tissues, thereby providing a platform conducive to reproductive cell growth and function. The performance of these scaffolds can be further optimized by regulating the cross-linking state and degradation rate of the ECM to meet the treatment needs of different aging-related diseases 148 . Furthermore, decellularized ECM can be processed into hydrogels to carry stem cells or growth factors. This hydrogel can provide a microenvironment for cells and serve as a storage and release platform for cytokines, thereby promoting the repair and regeneration of reproductive tissues 149 . Building on these foundations, ECM-based organoids and microfluidic technology are combined to construct miniaturized reproductive tissue models. These models emulate key physiological processes of reproductive tissues, providing an experimental platform for anti-reproductive aging research 150 . Currently, the main focus of research on the ECM of female reproductive organs has been on endometrial repair and ovarian function restoration, with most studies still in the preclinical stage 151 . Moreover, few interventions have specifically targeted the ECM to enhance fertility in women of advanced reproductive age. Overall, ECM scaffold-based anti-aging strategies offer a new approach to slow down the reproductive aging process and reverse the fertility decline in older women 152 . The following section outlines several potential ECM-targeted anti-reproductive aging strategies and their underlying mechanisms (Fig. 3 ). Fig. 3 Strategies targeting age-related ECM changes and related technological applications. At the core of these interventions is the targeting of ECM senescent changes through multiple strategies. For the approach of “Targeting ECM Senescence Changes”, anti-fibrotic drugs and cross-linking inhibitors are employed, which act on advanced glycation end products (AGEs) and lysyl oxidase (LOX). Additionally, regulation of the balance between tissue inhibitor of metalloproteinases (TIMP) and matrix metalloproteinases (MMP) is utilized as a key strategy. Related technological applications include three major categories: (1) “Decellularized ECM Scaffolds”; (2) “Microfluidics and Organoid Models”, featuring ovarian and uterine organoids as well as microfluidic systems; (3) “ECM Hydrogels and 3D Printed Bioinks”, which facilitate 3D cell culture, 3D bioprinting, and intrauterine perfusion. Abbreviations: AGEs, Advanced glycation end products; LOX, Lysyl oxidase; TIMP, Tissue inhibitor of metalloproteinases; MMP, Matrix metalloproteinases. Created with BioRender.com. At the core of these interventions is the targeting of ECM senescent changes through multiple strategies. For the approach of “Targeting ECM Senescence Changes”, anti-fibrotic drugs and cross-linking inhibitors are employed, which act on advanced glycation end products (AGEs) and lysyl oxidase (LOX). Additionally, regulation of the balance between tissue inhibitor of metalloproteinases (TIMP) and matrix metalloproteinases (MMP) is utilized as a key strategy. Related technological applications include three major categories: (1) “Decellularized ECM Scaffolds”; (2) “Microfluidics and Organoid Models”, featuring ovarian and uterine organoids as well as microfluidic systems; (3) “ECM Hydrogels and 3D Printed Bioinks”, which facilitate 3D cell culture, 3D bioprinting, and intrauterine perfusion. Abbreviations: AGEs, Advanced glycation end products; LOX, Lysyl oxidase; TIMP, Tissue inhibitor of metalloproteinases; MMP, Matrix metalloproteinases. Created with BioRender.com. In our previous discussion, we systematically analyzed the complex changes in the ECM during aging. These molecular disruptions lead to an imbalance in cell-ECM interactions, disrupting tissue homeostasis and causing functional degradation. Current research focuses on identifying critical age-related ECM changes and applying precise biotechnological interventions. During organ aging and fibrosis, normal ECM is progressively replaced by interstitial collagen, particularly types I and III, leading to tissue stiffness and dysfunction. Therapeutic strategies aimed at inhibiting collagen crosslinking have focused on targeting key enzymes and products such as LOX, TGase, and AGEs. For instance, the LOX inhibitor β-aminoproprionitrile has been shown to reduce aortic stiffness and atherosclerotic plaques in animal models. AGE inhibitors, including aminoguanidine and rosmarinic acid, have been shown to reduce ECM accumulation and improve outcomes in models of diabetic nephropathy, although their clinical application remains limited 153 . In polycystic ovary syndrome, abnormal MMP activity alters ECM degradation, thickening the ovarian cortex and increasing its collagen content, creating a rigid environment that disrupts normal follicular growth and oocyte maturation, leading to the accumulation of small, stagnant follicles and elevated androgen levels. Future therapeutic approaches may involve regulating MMP activity to normalize the mechanical properties of the ECM 154 . In the process of reproductive aging, targeting ovarian fibrosis with anti-fibrotic drugs, such as pirfenidone and BGP-15, eliminates fibrotic collagen in reproductively aged and obese mice and restores ovulation, which is associated with suppressed M2 macrophage polarization and increased MMP13 protease activity 147 . During embryo implantation, type I collagenase promotes endometrial ECM remodeling, degrading collagen fibers and proteoglycans, and releasing matrix-bound bioactive factors (such as VEGF, decorin), enhancing vascular permeability and angiogenesis, and improving the uterus’s receptivity to embryo implantation. This approach emphasizes key ECM remodeling mechanisms in embryo implantation 155 .In a mouse model of premature ovarian failure, intravenous infusion of human umbilical cord mesenchymal stem cells upregulates ECM-related gene expression, rebuilding ovarian ECM components and promoting follicular development 156 . This indicates that the ECM plays a crucial role in tissue regeneration. Research on restoring tissue function through ECM regulation has largely focused on reversing pathological fibrosis, with limited direct evidence that targeting physiological, age-related ECM changes can restore complex functions such as fertility. However, a pivotal study in Caenorhabditis elegans provides experimental evidence that repairing age-dysregulated ECM is integral to longevity 53 . The authors demonstrate that diverse genetic and pharmacological pro-longevity interventions (e.g., reduced insulin/IGF-1 signaling, dietary restriction, germline removal) converge to slow age-related ECM deterioration by modulating collagen dynamics. Furthermore, they identify a conserved mechanotransduction pathway involving hemidesmosomes and YAP-1 as essential for this process. While these specific interventions have not been directly replicated for fertility restoration in mammalian models, the study mechanistically elevates ECM homeostasis as a central axis in aging. This insight suggests that strategies aimed at maintaining a dynamic ECM could represent a promising frontier for addressing age-related functional decline, including reproductive aging 53 . Decellularized ECM scaffolds, derived from biological tissues, retain the native tissue’s three-dimensional structure and porosity. They exhibit excellent biocompatibility, significantly reduced immunogenicity, and maintain key mechanical properties and proteins, such as collagen and laminin, that are essential for promoting cell adhesion, migration, and differentiation 148 , 157 – 159 . These attributes render ECM scaffolds as ideal material for tissue engineering and regenerative medicine, including applications in reproductive aging. Decellularized uterine scaffolds (DUS/DES) have demonstrated remarkable efficacy in uterine regeneration, where their orientation and composition are critical for the structure and function of the regenerated tissue. In one key study, a decellularized uterine matrix was prepared via an SDS-based aortic perfusion method, which successfully preserved the scaffold’s three-dimensional architecture, vascular network, and uterus-specific ECM components. Following partial uterine excision in a rat model, the acellular scaffold was transplanted in situ and recellularized by seeding primary uterine cells alongside mesenchymal stem cells. Experimental results have confirmed that decellularized uterine matrix effectively supports uterine tissue regeneration and achieves pregnancy outcomes comparable to those of normal uteri in vivo, thereby validating its efficacy in uterine regeneration 160 . Furthermore, DUS orientation is vital for the regenerated uterus structure. Reverse implantation can induce structural abnormalities, although fertility may not be immediately impaired. Correct DUS orientation is more conducive to the formation of normal tissue structures 161 . Similarly, DES significantly enhances endometrial matrix regeneration but has not yet fully restored endometrial epithelial structure, which underscores its substantial potential for promoting endometrial matrix regeneration while highlighting the need for further research to achieve complete endometrial epithelial regeneration 162 . Collectively, these studies provide robust experimental evidence and theoretical support for the development of novel approaches to treat uterine factor infertility, particularly in the regeneration of endometrium and myometrium. In terms of ovarian regeneration, decellularized human ovarian tissue (DCT) exhibits great promise for constructing artificial ovaries. In vitro experiments have demonstrated that DCT provides support for the reseeding of human ovarian stromal cells and the survival of early follicular-stage follicles. In vivo experiments have shown that DCT supports the growth of mouse follicles, with 39% developing to the antral stage and a human follicle survival rate of 25%. Systematic review indicates that artificial ovaries based on decellularized extracellular matrix (dECM) can support the growth of ovarian cells and follicles, producing estrogen and progesterone, although high variability exists and experimental animal pregnancy or live birth has not yet been achieved 163 , 164 . Recent integration of robotic-assisted surgery and ECM scaffolds in ovarian tissue transplantation has significantly enhanced the success rate of ovarian function recovery and extended the survival time of transplanted tissues, thereby optimizing embryo quality and pregnancy outcomes. In clinical studies, ovarian function recovery time has been reduced to an average of 13.9 weeks, and the survival time of transplanted tissues has been prolonged to an average of 43.2 months, surpassing the previous average of 29.4 months. Among patients attempting to conceive, the pregnancy rate exceeds the global average of 25%, with some patients successfully delivering healthy babies 165 . These advancements not only offer a more effective approach for preserving fertility in women with chemotherapy-induced ovarian failure but also lay a solid foundation for the future development and broader application of ovarian tissue transplantation technology, holding the potential to further enhance patient fertility outcomes 166 . In summary, the ECM scaffolds of reproductive organs are a promising anti-aging approach. To advance the clinical translation of dECM-based artificial ovaries, it is essential to optimize decellularization protocols to enhance follicle survival and functional recovery while mitigating immune rejection 167 . Furthermore, refining the preparation and application strategies of decellularized scaffolds is expected to provide more effective methods for uterine tissue regeneration, ultimately addressing infertility resulting from structural and functional uterine impairments. Based on ECM scaffolds, ECM can be processed into hydrogels via enzymatic digestion, neutralization, and crosslinking enhancement. These ECM hydrogels offer extensive applications in treating female reproductive dysfunction 168 – 170 . Accumulating evidence shows that youth-derived ECM hydrogels remodel senescent niches in a concerted, organ-spanning manner. In the heart, ECM ligands override stiffening cues and enforce fibroblast quiescence 171 . In the kidney, dECM drives organoid vascularization and filtration-barrier maturation 172 . In the testis, collagen-I-rich dECM reactivates Leydig stem cells, restoring sustained testosterone production and simultaneously improving cognitive and musculoskeletal aging 173 . Collectively, ECM hydrogels fuse microenvironmental resetting with functional rejuvenation into a single, cohesive anti-aging platform. ECM hydrogels now serve as one platform for reproductive repair. In ovarian applications, a single intragonadal injection of ovarian ECM hydrogel loaded with 3D-MSC exosomes downregulates Bax and Gpd1and upregulates Sirpa, reactivating granulosa cells and increasing AMH, E2, and follicle counts 174 . In uterus repair, intrauterine injection of decellularized uterine ECM hydrogel upregulates IGFBP3 and downregulates IGF1, promoting gland and vasculature regeneration, reducing collagen deposition, and restoring endometrial receptivity and implantation capacity in thin-endometrium mouse models. Human explants also show sustained 3D epithelial-stromal growth 175 . 3D-derived exosomes exhibit higher yields compared to those from 2D versions. Key miRNAs, including miR-21-5p and miR-125b-5p, reverse follicular apoptosis via PTEN/PI3K-Akt pathway 176 – 178 . Thus, ECM hydrogels represent a tissue-specific, injectable, and acellular therapeutic strategy. Adding high-performance exosomes, growth factors, or stem cells could create a single treatment for chemotherapy-induced ovarian insufficiency, thin endometrium, and implantation failure. Advances in 3D printing technology have established ECM-based bioinks as a valuable tool in biomedical applications. Research indicates that ECM bioinks support cell survival and function, and promote tissue regeneration and repair. For instance, a study utilized decellularized ECM bioink derived from pig ovaries to successfully print 3D structures containing primary ovarian cells, which notably alleviated symptoms of ovarian failure in mice, demonstrating its potential in reproductive medicine 179 . Similarly, endometrial hydrogel has proven effective in repairing endometrial damage and enhancing embryo development, further highlighting the application prospects of ECM hydrogels in tissue repair and regenerative medicine 180 . These findings suggest that ECM bioinks not only provide an ideal environment for cell growth but also enable the construction of complex tissue models via 3D bioprinting, offering new solutions for personalized and precision medicine. Despite these advances, the application of ECM hydrogels in treating reproductive aging remains underexplored. Future research should focus on harnessing the anti-aging potential of ECM hydrogels to address conditions such as ovarian decline and endometrial thinning in aging populations. By leveraging the regenerative and anti-inflammatory properties of ECM hydrogels, there is potential to develop novel therapies that restore reproductive function and improve fertility outcomes in aging individuals.

Female reproductive aging has emerged as a defining health challenge of the 21st century. As global childbearing trends increasingly shift toward the fourth decade of life, age-related declines in ovarian reserve and oocyte quality now represent the leading cause of female infertility and a key constraint on the success of assisted reproductive technologies 1 . This biological deterioration extends beyond subfertility, presenting as elevated miscarriage rates, obstetric complications, and aneuploid pregnancies 2 , 3 . The downstream consequences of reproductive aging, estrogen withdrawal, and chronic inflammation further accelerate systemic aging, contributing to osteoporosis, cardiovascular disease, and cognitive decline 4 , 5 . Current studies primarily attribute reproductive aging to cell-intrinsic mechanisms, including telomere attrition, mitochondrial dysfunction, and cellular senescence within reproductive tissues 6 . While these mechanisms are undoubtedly central to reproductive aging, they do not fully explain the clinical observation that reproductive competence declines systemically with advancing age. For example, even interventions targeting these cellular deficiencies, such as optimal hormonal supplementation or the use of high-quality donor oocytes, often fail to restore the live-birth rates to those of younger women in recipients over 40 years of age 7 , 8 . This discrepancy implies the involvement of additional non-cellular factors in orchestrating reproductive decline, thereby prompting investigation into the extracellular matrix (ECM) as a previously underrecognized driver of reproductive aging. Recently designated the 13th hallmark of aging, the ECM undergoes characteristic age-related remodeling, including collagen cross-linking, elastin fragmentation, and advanced glycation end-products (AGEs) accumulation, which collectively increase tissue stiffness and create pro-fibrotic microenvironments 9 , 10 . These mechanical and biochemical alterations activate mechanosensitive pathways, particularly integrin-YAP signaling, which drive cellular senescence and tissue dysfunction through positive feedback loops 11 . In reproductive tissues specifically, the ECM provides essential mechanical flexibility for cyclic endometrial remodeling, facilitates follicular rupture during ovulation, and guides embryo implantation; these functions become severely compromised as matrix properties alter with age 12 . Recent proteomic analyses have revealed dramatic age-related shifts in the reproductive tissue matrisome: collagen fibers become hyper-cross-linked, hyaluronan degrades into inflammatory fragments, and basement membrane composition undergoes qualitative changes that correlate with declining follicle numbers and impaired decidualization 13 , 14 . These findings position ECM remodeling not as a passive consequence but as an active driver of reproductive aging. In this review, we synthesize recent evidence that ECM aging is a causal, targetable driver of reproductive decline. We map ECM-dependent molecular pathways linking tissue stiffening to follicular atresia, decidual failure, and immune dysregulation, and critically evaluate emerging ECM-based rejuvenation strategies—from decellularized scaffolds and designer hydrogels to matrisome-derived biomarkers—that may extend female reproductive lifespan.

Aging is defined by the progressive loss of tissue integrity and physiological reserve that constitutes an independent risk factor for cancer, neurodegeneration, and cardiovascular disease 38 , 39 . Although often viewed as a genetically driven process, accumulating evidence implicates environmental cues, particularly ECM remodeling, as rate-limiting determinants of organismal aging 40 . In animal models, disruption of circadian genes is known to accelerate aging 41 . Separately, ECM-derived biochemical and biomechanical signals can influence circadian rhythms 42 . While these findings suggest a potential interplay between ECM signaling and age-related decline, a direct mechanistic link integrating all three aspects (aging, ECM changes, and circadian disruption) warrants further investigation 43 . At the molecular level, aging elicits tissue-specific alterations in ECM composition and mechanics. Key alterations include the accumulation of fragmented collagen fibrils in the dermis 44 , an elevated type I/III collagen ratio along with AGEs deposition in the myocardium 45 , 46 , and the breakdown of elastin into bioactive peptides in arterial walls 47 . At the transcriptomic level, analyses based on the GTEx and MatrisomeDB 2.0 databases further reveal distinct organ-specific trajectories in the expression of ECM-related genes with aging. Studies have identified a set of core matrisome genes, including LTBP2, COL18A1, MFAP1, and IGFBP7, that show consistent age-associated expression changes across multiple tissues. Concurrently, significant differences in alteration patterns have been observed between tissues. For instance, the number of genes upregulated with age is markedly higher in muscle, lung, and blood than in the brain or the kidney. These findings at the gene expression level confirm that ECM aging exhibits pronounced tissue heterogeneity 48 , 49 . Furthermore, modeling studies demonstrate that aging transforms randomly oriented collagen networks into highly aligned and stiffened arrays, which can predict biological age better than chronological age 10 , 50 . These alterations are not merely passive. Longevity signaling cascades, including mTOR, IGF-1, and germline pathways, actively modulate ECM turnover, and their manipulation remodels the matrix in Caenorhabditis elegans via YAP-1-dependent mechanotransduction 51 – 53 . Among the hallmarks of aging, cellular senescence is closely linked to ECM remodeling. Senescent, apoptosis-resistant fibroblasts accumulate with age and through their senescence-associated secretory phenotype (SASP), drive the formation of a stiffer, pro-fibrotic matrix characterized by both altered composition and excessive deposition, including abnormal cross-linking and shifted collagen subtypes 54 . Matveeva et al. 55 demonstrated that senescent mesenchymal stem cells produce more inflammatory and pro-fibrotic factors, actively remodeling the ECM. Conversely, the aged ECM characterized by increased stiffness and cross-linking can induce cellular senescence through integrin signaling and mitochondrial reactive oxygen species production, contributing to tissue fibrosis and degeneration 11 , 56 . This self-amplifying loop between ECM alterations and cellular senescence accelerates the aging process and promotes age-related pathologies 57 . Given these insights, targeting ECM remodeling has emerged as a promising anti-aging strategy. Approaches aimed at modulating ECM turnover, such as inhibiting collagen cross-linking enzymes, using AGE inhibitors, or restoring ECM elasticity, are being explored to slow aging and extend healthspan 58 .