Dynamic in vitro culture of cryopreserved-thawed human ovarian cortical tissue using a microfluidics platform does not improve early folliculogenesis

Current strategies for fertility preservation include the cryopreservation of embryos, mature oocytes or ovarian cortical tissue for autologous transplantation. However, not all patients that could benefit from fertility preservation can use the currently available technology. In this regard, obtaining functional mature oocytes from ovarian cortical tissue in vitro would represent a major breakthrough in fertility preservation as well as in human medically assisted reproduction. In this study, we have used a microfluidics platform to culture cryopreserved-thawed human cortical tissue for a period of 8 days and evaluated the effect of two different flow rates in follicular activation and growth. The results showed that this dynamic system supported follicular development up to the secondary stage within 8 days, albeit with low efficiency. Surprisingly, the stromal cells in the ovarian cortical tissue were highly sensitive to flow and showed high levels of apoptosis when cultured under high flow rate. Moreover, after 8 days in culture, the stromal compartment showed increase levels of collagen deposition, in particular in static culture. Although microfluidics dynamic platforms have great potential to simulate tissue-level physiology, this system still needs optimization to meet the requirements for an efficient in vitro early follicular growth.

The effect of bpV(HOpic) on in vitro activation of primordial follicles in cultured swine ovarian cortical strips

The vanadate-derivative dipotassium bisperoxo (5-hydroxy-pyridine-2-carboxylic) oxovanadate (V) (bpV(HOpic)), a pharmacological inhibitor of phosphatase and tensin homolog (PTEN), has been used in ovarian follicle culture systems for activation of follicular growth in vitro and suggested to be responsible for primordial follicle survival through indirect Akt activation. For pig ovarian tissue, it is still not clear which culture medium needs to be used, as well as which factors and hormones could influence follicular development; this also applies to bpV(HOpic) exposure. Therefore, ovarian cortical strips from pigs were cultured in 1 µM bpV(HOpic) (N = 24) or control medium (N = 24) for 48 hr. Media were then replaced with control medium and all tissue pieces incubated for additional 4 days. The strips were embedded in paraffin for histological determination of follicle proportions at the end of the culture period and compared to histological sections from tissue pieces without cultivation, which had been embedded right after preparation; comparison of healthy follicles for each developmental stage was performed to quantify follicle survival and activation. After 6-day culture, follicle activation occurred in tissue samples from both cultured groups but significantly more follicles showed progression of follicular development in the presence of 1 µM bpV(HOpic). The amount of non-vital follicles was not significantly increased during cultivation. BpV(HOpic) affects pig ovarian follicle development by promoting the initiation of follicle growth and development, similar as in rodent species and humans.

Transcriptional profiling of long noncoding RNAs and their target transcripts in ovarian cortical tissues from women with normal menstrual cycles and primary ovarian insufficiency

Previous studies have shown that long noncoding RNAs (lncRNAs) show a highly tissue- and disease-specific expression pattern and that they regulate the expression of neighboring genes. Because lncRNAs have been shown to be secreted into the general circulation, they may be used as diagnostic tools for some diseases. Primary ovarian insufficiency (POI) is a disease in which women have menstrual cessation before the age of 40, accompanied by elevated follicle stimulating hormone and decreased estrogen levels. In this study, ovarian cortical tissues from five women with normal menstrual cycles and from five POI patients were used for next-generation RNA sequencing. We found 20 differentially expressed lncRNAs with 12 upregulated and eight downregulated lncRNAs in cortical tissues of POI ovaries, compared with normal controls (fold change ≥ 2 and false discovery rate[FDR] ≤ 0.05). We also found 52 differentially expressed messenger RNA transcripts, with 33 upregulated and 19 downregulated ones (foldchange ≥ 2 and FDR ≤ 0.05). Functional annotation showed that these differentially expressed transcripts were associated with follicular development and granulosa cell function. Thirteen differentially expressed lncRNAs and their targeted neighboring transcripts were coregulated in ovarian cortical tissues, including lnc-ADAMTS1-1:1/ADAMTS1, lnc-PHLDA3-3:2/CSRP1, lnc-COL1A1-5:1/COL1A1, lnc-SAMD14-5:3/COL1A1, and lnc-GULP1-2:1/COL3A1. Furthermore, serum levels of these lncRNAs in POI patients were significantly different from those in normal patients ( p < 0.05), and expression differences were consistent with those in ovarian cortical tissues. This study showed that key lncRNAs were differentially expressed in both ovarian cortical tissues and serum samples between women with normal menstrual cycles and POI patients. Further studies on the regulation of ovarian lncRNAs during follicular development are critical in understanding the etiologies of POI. Analyses of lncRNA expression in serum samples might provide a basis for early diagnosis and treatment of POI.