Impact of Advanced Reproductive Age on Mitochondrial Metabolism of Bone Marrow Mesenchymal Stem Cells from Infertile Women: Implications for Mitochondrial Transplantation.

AbstractThe decline in oocyte quality due to mitochondrial dysfunction is a frequent cause of infertility in women of advanced reproductive age. Autologous bone marrow mesenchymal stem cells could serve as a source of transplanted mitochondria for infertility treatment. However, the status of transplanted mitochondria may affect therapeutic potential. Although the effects of donor age and long-term culture on BMSC quality have been previously documented, it remains unclear whether advanced reproductive age and in vitro culture affect the mitochondrial metabolism of BMSCs from infertile women.Methods: BMSCs from young (25-30 years) and older (38- 45 years) infertile women were cultured and collected at passage 4 (P4) to P7. We evaluated their surface markers, proliferation capacity, mitochondrial oxygen consumption rate (OCR), reactive oxygen species (ROS), membrane potential (activity), ultrastructure, and the transcriptomic analysis of 38 mitochondrial processes (mito-processes).Results: Both age groups of BMSCs exhibited the stable expression of surface markers, decreased proliferation capacity, and increased mitochondrial OCR and ROS production with increasing passage. There were no differences between the two age groups in terms of these indexes. For transcriptomic analysis, only two mito-processes changed for BMSCs from the older group at consecutive passages, showing upregulation of ROS defense (MPV17L) and mitochondrial carrier (UCP2). In contrast, in the young group, P5 BMSCs showed upregulation of nine mito-processes, including OXPHOS, apoptosis, translation, and P6-P7 showed consistent upregulation of calcium signaling and transport (EFHD1) and downregulation of four mito-processes in total. Compared with the older group, the young group showed differences in fifteen mito-processes, most of which negatively affected mitochondrial metabolism.Conclusions: Advanced reproductive age has little impact on the mitochondrial metabolism of BMSCs from infertile women. Early-passage BMSCs are recommended for further application under the premise of controlling individual differences. Our work provides valuable guidance for the clinical application of autologous mitochondria from BMSCs, particularly for older women seeking infertility treatment.