Methylation status of H19/IGF2 differentially methylated region in in vitro human blastocysts donated by healthy couples

Backgrund: Imprinted genes are a unique subset of few genes, which have been differentially methylated region [DMR] in a parental origin-dependent manner during gametogenesis, and these genes are highly protected during pre-implantation epigenetic reprogramming. Several studies have shown that the particular vulnerability of imprinting genes during suboptimal pre- and peri-conception micro-environments often is occurred by assisted reproduction techniques [ART]. This study investigated the methylation status of H19/IGF2 DMR at high-quality expanding/expanded human blastocysts donated by healthy individuals to evaluate the risks linked to ART

Method: Methylation levels of H19/IGF2 DMR were analyzed by bisulfite conversion and sequencing at 18 CpG sites [CpGs] located in this region

Result: The overall percentage of methylated CpGs and the proportion of hyper-methylated clones of H19/IGF2 DMR in analyzed blastocysts were 37.85 +/- 4.87% and 43.75 +/- 5.1%, respectively. For validation of our technique, the corresponding methylation levels of peripheral human lymphocytes were defined [49.52 +/- 1.86% and 50%, respectively]

Conclusion: Considering the absence of in vivoproduced human embryos, it is not possible to conclude that the methylation found in H19/IGF2 DMR is actually normal or abnormal. Regarding the possible risks associated with ART, the procedures should be optimized in order to at least reduce some of the epigenetic risks

Factors influencing sperm retrieval following testicular sperm extraction in nonobstructive azoospermia patients / 대한생식의학회지

OBJECTIVE: Azoospermia owing to testicular disorders is the most severe manifestation of male infertility. The main concern for patients with nonobstructive azoospermia (NOA) is the probability of successful sperm retrieval following testicular sperm extraction (TESE). Therefore, the goal of this study was to determine predictive factors correlated with sperm retrieval. METHODS: We assessed the testicular histopathological patterns, the choice of TESE surgical procedure, hormone levels, and chromosomal abnormalities in patients with NOA (n=170). The histopathology specimens were analyzed based on the histopathological patterns of hypospermatogenesis, maturation arrest, and Sertoli cell-only syndrome. RESULTS: The mean rate of sperm retrieval was 48.8%. The rate of sperm retrieval was significantly higher in the hypospermatogenesis group than in the other groups (p<0.001). There was a positive correlation between micro-TESE (vs. conventional TESE) and the sperm retrieval rate (odds ratio, 8.077; p<0.01). A logistic regression model demonstrated that high levels of follicle-stimulating hormone (FSH) and small testicular volume were significantly associated with lower chances of successful sperm retrieval. CONCLUSION: Some parameters, including testicular histopathology patterns, FSH levels, testicular volume, and method of TESE surgery, may be able to predict the chances of obtaining spermatozoa in patients with NOA. However, despite the efficiency of some predictive models, the hope of retrieving any functioning spermatozoa may be sufficient to disregard predictive factors of the success of intracytoplasmic sperm injection in these patients.