Evaluation of Controlled Ovarian Stimulation Protocols in Patients with Normal and Low Ovarian Reserve: Analyses of miRNAs and Selected Target Genes Involved in the Proliferation of Human Cumulus Cells and Oocyte Quality.

The oocyte and the surrounding cumulus cells (CCs) are deeply linked by a complex bidirectional cross-talk. In this light, the molecular analysis of the CCs is nowadays considered to be precious in providing information on oocyte quality. It is now clear that miRNAs play a key role in several ovarian functions, such as folliculogenesis, steroidogenesis, and ovulation. Thus, in this study, specific miRNAs, together with their target genes, were selected and investigated in CCs to assess the response of patients with normal (NR) and low (LR) ovarian reserve to two different controlled ovarian stimulation (COS) protocols, based on rFSH and hMG. Moreover, a Fourier transform infrared microspectroscopy (FTIRM) analysis was performed to evaluate DNA conformational changes in CCs and to relate them with the two COS protocols. The results evidenced a modulation of the expression of miRNAs and related target genes involved in CCs' proliferation, in vasculogenesis, angiogenesis, genomic integrity, and oocyte quality, with different effects according to the ovarian reserve of patients. Moreover, the COS protocols determined differences in DNA conformation and the methylation state. In particular, the results clearly showed that treatment with rFSH is the most appropriate in NR patients with normal ovarian reserve, while treatment with hMG appears to be the most suitable in LR patients with low ovarian reserve.

The Impact of Controlled Ovarian Stimulation Hormones on the Metabolic State and Endocannabinoid System of Human Cumulus Cells.

Different Follicle Stimulating Hormone (FSH) formulation and Luteinizing Hormone (LH) are used in Assisted Reproductive Technology (ART) to induce follicles development and oocytes maturation, but it is still under debate which protocol is to be preferred. In the present study, the different effects on cumulus cells (CCs) of three controlled ovarian stimulation (COS) protocols, based on urinary FSH, recombinant FSH, or human Menopausal Gonadotropin (hMG) administration, were assessed. CCs were obtained from 42 normal-responders women undergoing COS, randomly divided into three groups according to the used gonadotropin formulation. Differences were found in the expression of genes belonging to the endocannabinoid system (the receptors CNR1, CNR2 and TRPV1, and the enzymes involved in the metabolisms of anandamide, NAPE-PLD and FAAH, and 2-acylglycerol, DAGL and MAGL); consistently, changes in lipid (PPARα, and FASN) and carbohydrate (GLUT1 and GLUT9) metabolisms, in CCs' macromolecules composition (highlighted by Fourier Transform Infrared Microspectroscopy, FTIRM), and in the number of retrieved oocytes were found. For the first time, statistically significant evidence on the differences related to each COS protocol on the endocannabinoid system, metabolism and macromolecular composition of CCs was found, representing a proof of concept to be further confirmed in a larger cohort of patients.