Astaxanthin alleviates chronic prostatitis/chronic pelvic pain syndrome by increasing colonization of Akkermansia muciniphila in the intestine

Background: Astaxanthin (AST) is a natural compound with anti-inflammatory/immunomodulatory properties that has been found to have probiotic properties. However, the role and mechanism of AST in chronic prostatitis/ chronic pelvic pain syndrome (CP/CPPS) are still not fully understood.Purpose: The aim of this study was to evaluate the effect of AST on CP/CPPS and elucidate the mediating role of the gut microbiota.Materials and methods: An experimental autoimmune prostatitis (EAP) mouse model was utilized to test the potential role of AST on CP/CPPS. Antibiotic cocktail (ABX) treatment and fecal microbiota transplantation (FMT) were used to elucidate the gut microbiota-mediated effects on AST. In addition, 16S rRNA gene sequencing and qRT-PCR analyses were used to analyze changes in the gut microbiota of EAP mice and CP/CPPS patients. Finally, the mechanism by which AST exerts a protective effect on CP/CPPS was explored by untargeted metabolomics and gut barrier function assays.Results: Oral administration of AST reduced prostate inflammation scores, alleviated tactile sensitization of the pelvic region in EAP mice, reduced CD4+ T cell and CD68+ macrophage infiltration in the prostatic interstitium, and inhibited the up-regulation of systemic and localized pain/pro-inflammatory mediators in the prostate. After ABX, the protective effect of AST against CP/CPPS was attenuated, whereas colonization with fecal bacteria from AST-treated EAP mice alleviated CP/CPPS. 16S rRNA gene sequencing and qRT-PCR analyses showed that Akkermansia muciniphila in the feces of EAP mice and CP/CPPS patients showed a trend toward a decrease, which was associated with poor progression of CP/CPPS. In contrast, oral administration of AST increased the relative abundance of A. muciniphila, and oral supplementation with A. muciniphila also alleviated inflammation and pain in EAP mice. Finally, we demonstrated that both AST and A. muciniphila interventions increased serum levels of SCFAs acetate, up-regulated expression of colonic tight junction markers, and decreased serum lipopolysac-charide levels in EAP mice.Conclusion: Our results showed that AST improved CP/CPPS by up-regulating A. muciniphila, which provides new potentially effective strategies and ideas for CP/CPPS management.