P-316 Endometrial inflammation and insulin resistance in adenomyosis: a vicious cycle potentially affecting fertility

Abstract Study question Does insulin resistance affect the immune-inflammatory status in infertile women with adenomyosis? Summary answer Insulin resistance worsens endometrial inflammation, disrupting immune cell recruitment and stromal proliferation in adenomyosis, potentially impairing the decidualization required for embryo implantation and pregnancy success. What is known already Adenomyosis is an estrogen-dependent disease, characterized by the presence of endometrial glands and stroma within the myometrium, associated with a uterine proinflammatory environment. Prolonged exposure to proinflammatory factors, such as IL1ß, can lead to insulin resistance (IR), which is the reduced ability of insulin to promote glucose uptake into cells. This proinflammatory mediator has been linked to both adenomyosis and recurrent miscarriage. Likewise, IR has been associated with increased miscarriage likelihood in assisted reproduction. Therefore, an inflammatory environment could lead to IR, and the confluence of both conditions in adenomyosis women may be a key factor in their worsened fertility. Study design, size, duration Twenty-one endometrial samples were collected from patients with and without adenomyosis undergoing hormonal replacement therapy before in vitro fertilization at IVIRMA clinics in Valencia and Rome. Based on ultrasound, patients were diagnosed with adenomyosis according to the MUSA criteria, while the oral glucose tolerance test evaluated IR status. Participants/materials, setting, methods Control–IR (n = 6) included infertile patients without either adenomyosis or IR, Adeno+IR (n = 8) included adenomyosis patients with IR, and Adeno–IR (n = 7) included adenomyosis patients without IR. Eutopic endometrial biopsies were collected in hormonal replacement cycles at the secretory phase (P + 5). Proteins were extracted and used to assess the relative expression of 160 cytokines through a Human Cytokine Array (Raybiotech). A functional enrichment analysis with the proteins differentially expressed was performed using the STRING database. Main results and the role of chance The analysis identified 10 cytokines with altered expression in Adeno+IR involved in immune cell recruitment (MDC, VCAM-1, MIP1ß), inflammation (IL1ß, IL1R1), proliferation (TGFa, BTC) and insulin-like growth factor family members (IGFBP3/4/6). IL1ß was upregulated in Adeno+IR (320.1±248.5, p = 0.0446) and Adeno-IR (120.4±32.78, p = 0.0333) compared to Control-IR (56.78±56.98), showing Adeno+IR the highest expression. Similarly, versus Control-IR (91.64±9.43), Adeno-IR showed a slight increase in IL1R1 expression (97.9±21.15, p = 0.5229), which was statistically significant in Adeno+IR (112.1±19.68, p = 0.0378). IGFBP3, induced by IL1ß, was upregulated in Adeno-IR (162.3±62.89, p = 0.0660) and significantly overexpressed in Adeno+IR (158.9±46.70, p = 0.0294) compared to Control-IR (104.9±29.70). MIP1ß (upregulated in secretory endometrium and involved in natural killer recruitment) was downregulated in Adeno+IR versus Control-IR (55.88±17.04 vs. 129.8±40.08, p = 0.0026). Other downregulated cytokines in Adeno+IR versus Control-IR were IGFBP4 (83.98±10.31 vs. 123.1±33.53, p = 0.0133), important for decidualization, IGFBP6 (97.15±38.02 vs. 142.8±16.88, p = 0.0185) and VCAM-1 (93.45±9.256 vs. 105.1±10.44, p = 0.0467). Meanwhile, TGFa (175.0±8.672 vs. 106.7±40.12, p = 0.0082), and BTC (110.1±15.34 vs. 87.75±19.91, p = 0.0346) were upregulated. Functional enrichment analysis identified 27 Biological Processes grouped in inflammation, immune response/recruitment, EGFR signaling, MAPK pathway, IGF signaling, signal transduction and cellular response; and 19 KEGG pathways like NF-kappa B and TNF signaling pathways, Th17 cell differentiation and AGE-RAGE signaling pathway in diabetic complications. Limitations, reasons for caution Our findings are limited by the relatively small sample size and inherent biological variability of human samples. The patients with adenomyosis presented different type (diffuse or focal) and grade of the disease. Wider implications of the findings Prolonged exposure to the pro-inflammatory mediators in endometrium of adenomyosis women may disrupt insulin signaling pathways leading to IR status. This condition, in turn, exacerbates the local endometrial inflammation in these patients, impairing immune cell recruitment, decidualization and endometrial receptivity, which are critical for successful embryo implantation and pregnancy progression. Trial registration number No