Polycystic ovary syndrome (PCOS) is a prevalent endocrine condition characterised by a range of endocrine, reproductive and metabolic abnormalities. At present, management of women with PCOS is suboptimal as treatment is only symptomatic. Clinical and experimental advances in our understanding of PCOS etiology support a pivotal role for androgen neuroendocrine actions in PCOS pathogenesis. Hyperandrogenism is a key PCOS trait and androgen actions play a role in regulating the kisspeptin-/neurokinin B-/dynorphin (KNDy) system. This study aimed to investigate if targeted antagonism of neurokinin B signalling through the neurokinin 3 receptor (NK3R) would reverse PCOS traits in a dihydrotestosterone (DHT)-induced mouse model of PCOS. After 3 months, DHT exposure induced key reproductive PCOS traits of cycle irregularity and ovulatory dysfunction, and PCOS-like metabolic traits including increased body weight; white and brown fat pad weights; fasting serum triglyceride and glucose levels and blood glucose iAUC. Treatment with a NK3R antagonist (MLE4901) did not impact the observed reproductive defects. In contrast, following NK3R antagonist treatment, PCOS-like females displayed decreased total body weight, adiposity and adipocyte hypertrophy, but increased respiratory exchange ratio, suggesting NK3R antagonism altered the metabolic status of the PCOS-like females. NK3R antagonism did not improve circulating serum triglyceride or fasted glucose levels. Collectively, these findings demonstrate that NK3R antagonism may be beneficial in the treatment of adverse metabolic features associated with PCOS and support neuroendocrine targeting in the development of novel therapeutic strategies for PCOS.

STUDY QUESTION Does AZD5904, a myeloperoxidase inhibitor (MPOi), have any effect on human sperm function in vitro? SUMMARY ANSWER AZD5904 improves sperm function in an in vitro model of oxidative stress (OS) and potentially offers a novel treatment approach for male infertility. WHAT IS KNOWN ALREADY Male infertility is an underlying or contributory cause in half of all couples experiencing difficulties conceiving, yet there is currently no effective treatment or cure. OS is a common pathology in a significant proportion of infertile men. It can negatively affect sperm motility and the ability to fertilize a mature oocyte, as well as DNA integrity, and therefore represents an attractive target for therapeutic intervention. STUDY DESIGN, SIZE, DURATION This study included population-based samples from men (23–50 years) attending Ninewells Assisted Conception Unit, Dundee for diagnostic semen analysis, July 2017–September 2018. Semen samples (n = 47) from 45 patients were used. PARTICIPANTS/MATERIALS, SETTING, METHODS Neutrophils activated using zymosan were incubated with prepared human spermatozoa for 2 h (T2) and 24 h (T24) to create an in vitro model of OS. Parallel samples were co-incubated with AZD5904, an MPOi, to examine its effects. Sperm motility was assessed by computer-assisted sperm analysis at T2 and T24. Functional motility was assessed by sperm penetration assay. Statistical analysis was performed using GraphPad Prism. MAIN RESULTS AND THE ROLE OF CHANCE There was no significant difference in total or progressive sperm motility between any treatment and control groups at T2 or T24. Nonetheless, significant positive effects on sperm function were observed with AZD5904, with 16/45 (35.6%) samples (with both normal and abnormal baseline semen analysis characteristics) displaying a ≥20% increase in sperm penetrated through viscous media (P < 0.003). LIMITATIONS, REASONS FOR CAUTION This was an in vitro study. WIDER IMPLICATIONS OF THE FINDINGS Treatment with AZD5904 resulted in significant increased sperm penetration in one of three samples treated, which is likely to represent improvement in sperm function required for fertilization. We are now planning a clinical trial to validate these results and hope that this could represent a new treatment for male infertility. STUDY FUNDING/COMPETING INTEREST(S) AZD5904 was shared through the AstraZeneca Open Innovation program. The study was funded by AstraZeneca and sponsored by the University of Dundee. Additional funding was provided by Chief Scientist Office/NHS Research Scotland (S.J.M.d.S.). A.W. and H.J.S. are both full time employees of AstraZeneca. A.W. and H.J.S. are inventors on a patent filed by AstraZeneca titled MPOi for use in medicine which includes MPOi for use in the treatment of male infertility (WO 2019/016074 Al). S.J.M.d.S. is Associate Editor of Human Reproduction and Editorial Board member of Reproduction & Fertility. C.L.R.B. is Editor of RBMO and has received lecturing fees from Merck and Ferring and is on the Scientific Advisory Panel for Ohana BioSciences. C.L.R.B. was chair of the World Health Organization Expert Synthesis Group on Diagnosis of Male infertility (2012–2016). C.L.R.B. has a patent WO2013054111 A1 issued. The other authors declare no conflict of interest. TRIAL REGISTRATION NUMBER N/A.

Background: Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine condition affecting up to 20% of reproductively aged women worldwide. Owing to an ambiguous etiology and complicated pathophysiology, current PCOS treatments remain purely symptomatic. Aberrations in androgen receptor driven neuroendocrine pathways are reportedly involved in the pathogenesis of PCOS. A clinical trial, focusing on the androgen regulated kisspeptin-neurokinin B-dynorphin system, treated women with PCOS with a neurokinin B receptor (neurokinin 3 receptor, NK3R) antagonist and reported improvements in LH secretion, LH pulses and testosterone levels. Aim: To investigate if pharmacological antagonism of NK3R can ameliorate PCOS traits in a mouse model. Method: Reproductive and metabolic features of PCOS were evaluated in control and dihydrotestosterone (DHT)-induced PCOS mice, treated +/-NK3R antagonist (MLE4901) for 28 days at a dose of 25mg/kg/day. Results: PCOS-like mice were acyclic and exhibited ovulatory dysfunction, which were not rescued by NK3R antagonist treatment. Compared to control mice, the PCOS-like mice displayed a significant increase in total body weight and inguinal, parametrial, mesenteric, retroperitoneal, and brown fat pad weights (all P[Formula: see text]0.01). NK3R antagonism partially reversed the total body weight and fat pad weight gains (all P[Formula: see text]0.01) in all white fat depots of PCOS-like mice. PCOS-like mice also displayed adipocyte hypertrophy and increased leptin levels compared to control mice (both P[Formula: see text]0.01), which were improved with NK3R antagonism treatment (P[Formula: see text]0.01 and P[Formula: see text]0.05, respectively). Moreover, DHT exposure significantly reduced the respiratory exchange ratio (RER) (P[Formula: see text]0.01), whereas NK3R antagonism significantly increased RER compared to control mice (P[Formula: see text]0.01), suggesting a metabolic shift in the PCOS-like mice treated with the NKR3 antagonist. Conclusion: These findings show that pharmacological antagonism of the kisspeptin-neurokinin system may be a beneficial treatment for adverse metabolic features of PCOS. This study also reveals important new insights into neuroendocrine androgen actions in the pathogenesis of PCOS.