Poster: Impact of ketogenic diet on semen quality in obesepatients: Cytological and molecular aspects, a pilot study

Introduction: Obesity is a metabolic disease with severe comorbidities, including hypogonadism and infertility. In fact, it induces chronic inflammatory responses with adverse effects on many tissues, including testicular function, by modulating cytokines, adipokines, and oxidative stress. This condition could cause sperm DNA fragmentation (SDF), protein and lipid damage with a negative impact on fertilization, and embryo development. Moreover, mammalian sperm RNA is increasingly recognized as an additional source of paternal hereditary information beyond DNA. Environmental aspects, including an unhealthy diet and obesity, can modify the sperm RNA signature and impact on development of the early embryo and offspring health. Weight loss intervention could improve reproductive function and ketogenic diet (KD) is one of the most employed dietary system in the last time. Specifically, KD is a high-fat, low-protein, very lowcarbohydrate diet with significant effects not only on weight but also on lowering serum lipids and blood glucose. It improves inflammatory state obesity-related through the action of ketone bodies, produced by liver in higher than normal quantities. Animal studies show that ketones can fuel sperm motility. To date, there is no information on the effect of KD on semen quality. Aim: The aim was to evaluate KD and weight loss effects on male gonadal function, evaluating hormonal profile (FSH, LH, and TT), sperm cytological (semen parameters), and molecular aspects (SDF and sperm miR-34c,miR-449b levels). Results: Anthropometric characteristics—age 36.8 ± 10.2 years; median pre-KD BMI 38.4 kg/m2 and median post-KD BMI 34.9 kg/m2. The difference between pre- and post-BMI was statistically significant (p-value = 0.031). Hormonal profile—we found a statistically significant difference (p-value = 0.032) between pre- and post-diet TT values: pre-KD TT = 8.3 nmol/L; post-KD = 11.2 nmol/L.We found no statistically significant differences in semen parameters before and after KD. Semen parameters were in the 25th percentile both before and after KD (WHO 2021). Sperm chromatin integrity—we observed a statistically significant difference in SDF% between pre-KD patients median 16.0% versus post-KD patients median 9.7% (p-value = 0.031). Expression of miR-34c and miR-449b—we detected a statistically significant increase in miR-34c expression in spermatozoa from preversus post-KD patients (1.7 vs. 8.5 pre- vs. post-diet, respectively; p-value = 0.031). We found no significant differences in miR-449b expression. Discussion and Conclusion: Several studies link obesity with oligoazoospermia and hormonal alterations. Contrary to literature, obese patients in our pilot study had good semen parameters and comparing obese pre- versus post-KD, we found a statistically significant increase in serum TT levels, according to literature. Our results show for the first time that KD-induced weight loss can improve sperm molecular parameters: reduced SDF% and increased miR-34c expression post-KD. Literature data indicate that SDF% and sperm-borne miRNAs expression, in particular miR-34c could influence early embryonic development. To date, human studies on KD-effect on male gametes are rare, and our pilot study suggests useful information on the potential effect of KD to improve molecular quality of sperm, with possible implications for embryonic development and offspring health.