As a major component of the extracellular matrix, hyaluronan (HA) plays an important role in defining the biochemical and biophysical properties of tissues. In light of the extremely rapid turnover of HA and the impact of this turnover on HA biology, elucidating the molecular mechanisms underlying HA catabolism is key to understanding the in vivo functions of this unique polysaccharide. Here, we show that TMEM2, a recently identified cell surface hyaluronidase, plays an essential role in systemic HA turnover. Employing induced global Tmem2 knockout mice (Tmem2^iKO), we determined the effects of Tmem2 ablation not only on the accumulation of HA in bodily fluids and organs, but also on the process of HA degradation in vivo. Within 3 weeks of tamoxifen-induced Tmem2 ablation, Tmem2^iKO mice exhibit pronounced accumulation of HA in circulating blood and various organs, reaching levels as high as 40-fold above levels observed in control mice. Experiments using lymphatic and vascular injection of fluorescent HA tracers demonstrate that ongoing HA degradation in the lymphatic system and the liver is significantly impaired in Tmem2^iKO mice. We also show that Tmem2 is strongly expressed in endothelial cells in the subcapsular sinus of lymph nodes and in the liver sinusoid, two primary sites implicated in systemic HA turnover. Our results establish TMEM2 as a physiologically relevant hyaluronidase with an essential role in systemic HA catabolism in vivo, acting primarily on the surface of endothelial cells in the lymph nodes and liver.

The benefits of novel androgen receptor axis-targeted agents (ARATs) on oncological outcomes in patients with non-metastatic castration-resistant prostate cancer (nmCRPC) in real-world settings are unclear. This multi-institutional retrospective study included 178 patients with nmCRPC treated between September 2003 and August 2022. Patients were divided into two groups: those who were treated with any novel ARATs, including apalutamide, enzalutamide, darolutamide, and abiraterone acetate, during any line of nmCRPC treatment (novel ARATs group) and those who were not (control group). Multivariable Cox proportional hazards regression analyses were performed to evaluate the effects of novel ARATs on metastasis-free survival (MFS) and overall survival (OS). The median age and follow-up period after nmCRPC diagnosis were 76 years and 37 months, respectively. Of the 178 patients, 122 (69%) were treated with novel ARATs after nmCRPC diagnosis. The MFS and OS in the novel ARATs group were significantly longer than those in the control group (P < 0.001 and P = 0.020, respectively). In multivariable analyses, a prostate-specific antigen doubling time (PSADT) of <3 months and novel ARATs were independently and significantly associated with MFS and OS. The effects of novel ARATs on MFS were consistently observed across subgroups stratified by age (<75 years or ≥75 years), history of radical treatment (no or yes), biopsy Gleason score (<9 or ≥9), clinical stage (≤cT3 and cN0, or cT4 or cN1), and PSADT (≥3 months or <3 months). Novel ARATs were significantly associated with improved oncological outcomes in patients with nmCRPC in a real-world setting, regardless of tumor aggressiveness.

In addition to testosterone, various endocrine hormones, such as dehydroepiandrosterone sulfate (DHEA-S) and estradiol, may be involved in erectile function. However, the role of these sex hormones in the erectile function of men without hypoandrogenism remains unclear. This cross-sectional study included 398 community-dwelling men without hypoandrogenism. The participants were categorized into the non-ED and ED groups. Multivariable logistic regression analyses were performed to investigate the relationship between ED and serum sex hormone levels, including total testosterone, DHEA-S, estradiol, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin. Among the 398 men, 66 (17%) and 332 (83%) were categorized into the non-ED and ED groups, respectively. In the multivariable analyses, serum DHEA-S and estradiol levels were significantly associated with ED (odds ratio [OR]: 0.996, P = 0.030; OR: 1.082, P = 0.002; respectively), whereas serum total testosterone, LH, FSH, and prolactin levels did not demonstrate significant association. After adjusting for age, none of neutrophil-to-lymphocyte ratio, serum plasminogen activator inhibitor-1 levels, and skin advanced glycation end-products levels demonstrated significant correlation with serum DHEA-S and estradiol levels. In conclusion, lower testosterone levels did not affect ED in men with normal testosterone levels, whereas serum DHEA-S and estradiol levels were significantly associated with ED.

Fujita N, et al. World J Mens Health. 2023 Jan;41:e17. https://doi.org/10.5534/wjmh.220154