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ObjectiveThe long interspersed elements (LINE-1, L1s) are a group of genetic elements found in large numbers in the human genome that can translate into phenotype by controlling genes. Growing evidence supports the role of epigenetic in polycystic ovary syndrome (PCOS). The purpose of this study is to evaluate the DNA methylation levels in LINE-1 in a tissue-specific manner using cumulus cells from patients with PCOS compared with normal controls.MethodsThe study included 19 patients with PCOS and 22 control patients who were undergoing controlled ovarian hyperstimulation. After oocyte retrieval, cumulus cells were extracted. LINE-1 DNA methylation levels were analysed by bisulfite treatment, polymerase chain reaction, and restriction enzyme digestion. The Connection Up- and Down-Regulation Expression Analysis of Microarrays software package was used to compare the gene regulatory functions of intragenic LINE-1.ResultsThe results showed higher LINE-1 DNA methylation levels in the cumulus cells of mature oocytes in PCOS patients, 79.14 (±2.66) vs. 75.40 (±4.92); p=0.004, but no difference in the methylation of cumulus cells in immature oocytes between PCOS and control patients, 70.33 (±4.79) vs. 67.79 (±5.17); p=0.155. However, LINE-1 DNA methylation levels were found to be higher in the cumulus cells of mature oocytes than in those of immature oocytes in both PCOS and control patients.ConclusionThese findings suggest that the epigenetic modification of LINE-1 DNA may play a role in regulating multiple gene expression that affects the pathophysiology and development of mature oocytes in PCOS.

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Objective: Using domestic cats as a biomedical research model for fertility preservation, the present study aimed to characterize the influences of ovarian tissue encapsulation in biodegradable hydrogel matrix (fibrinogen/thrombin) on resilience to cryopreservation, and static versus non-static culture systems following ovarian tissue encapsulation and cryopreservation on follicle quality.Methods: In experiment I, ovarian tissues (n=21 animals; 567 ovarian fragments) were assigned to controls or hydrogel encapsulation with 5 or 10 mg/mL fibrinogen (5 or 10 FG). Following cryopreservation (slow freezing or vitrification), follicle viability, morphology, density, and key protein phosphorylation were assessed. In experiment II (based on the findings from experiment I), ovarian tissues (n=10 animals; 270 ovarian fragments) were encapsulated with 10 FG, cryopreserved, and in vitro cultured under static or non-static systems for 7 days followed by similar follicle quality assessments. Results: In experiment I, the combination of 10 FG encapsulation/slow freezing led to greater post-thawed follicle quality than in the control group, as shown by follicle viability (66.9%±2.2% vs. 61.5%±3.1%), normal follicle morphology (62.2%±2.1% vs. 55.2%±3.5%), and the relative band intensity of vascular endothelial growth factor protein phosphorylation (0.58±0.06 vs. 0.42±0.09). Experiment II demonstrated that hydrogel encapsulation promoted follicle survival and maintenance of follicle development regardless of the culture system when compared to fresh controls.Conclusion: These results provide a better understanding of the role of hydrogel encapsulation and culture systems in ovarian tissue cryopreservation and follicle quality outcomes using an animal model, paving the way for optimized approaches to human fertility preservation.

Objective: To investigate the prevalence of empty follicle syndrome (EFS), a condition in which no oocytes were retrieved after ovarian stimulation, categorized into genuine EFS (g-EFS) and false EFS (f-EFS), at the King Chulalongkorn Memorial Hospital (KCMH), Thailand. Materials and Methods: A retrospective study was conducted at the infertility clinic of the KCMH. Medical records of the assisted reproductive technology (ART) patients between January 2001 and October 2019 (5,523 patients) were reviewed. Exclusion criteria were the cases where ovulation occurred before oocyte retrieval or the cases with less than four follicles larger than 14 mm diameter on the day of triggering ovulation to minimize the absence of oocyte from the poor response. The patients with EFS, g-EFS, which are EFS with detectable urinary human chorionic gonadotropin (hCG), and f-EFS, which are EFS with undetectable urinary hCG, were identified. Prevalence of EFS was calculated. Results: There were three cases with EFS in the present study, which g-EFS was identified in one case and f-EFS in two cases. The prevalence of EFS was 0.054%, which g-EFS was 0.018% and f-EFS was 0.036%. Conclusion: EFS is a rare condition, particularly the g-EFS. Although EFS is rare, it causes tremendous stress and anxiety to both patients and physicians. Further study in the etiopathogenesis of EFS is required. Keywords: Empty follicle syndrome; Infertility; In vitro fertilization