This study aimed to investigate the effects of trimethylamine N-oxide (TMAO) on vascular calcification (VC) in db/db mice induced by a high-phosphorus diet and to identify the associated molecular pathways. To establish a VC model, db/db mice were fed an adenine-supplemented high-phosphorus diet, with TMAO and its inhibitor 3,3-dimethyl-1-butanol (DMB) administered via drinking water. The effect of TMAO on renal pathology and colonic mucosal barrier function in db/db mice was evaluated. Micro-computed tomography (Micro-CT) and Von Kossa staining were used to evaluate the degree of aortic calcification. Western blotting, immunohistochemistry, immunofluorescence, and RT-qPCR were employed to detect the proteins and mRNAs related to the sirtuin 1 (SIRT1)/nuclear factor-κB p65 (NF-κB p65)/NOD-like receptor pyrin domain-containing 3 (NLRP3) signaling pathway. Sequencing of the 16S rRNA gene was performed to analyse changes in the gut microbiota. We found that the serum TMAO level in db/db-VC model mice was significantly elevated, accompanied by calcium and phosphorus metabolism disorders and gut microbiota imbalance, mainly manifested as an increase in the abundance of Prevotella and Desulfovibrio. TMAO aggravated renal dysfunction and intestinal barrier injury in db/db-VC mice and induced a certain degree of inflammatory response. Moreover, TMAO intervention significantly upregulated the expression of osteogenic marker proteins. In contrast, inhibition of TMAO production by DMB significantly reduced VC. Mechanistically, TMAO inhibited the activity of the SIRT1 deacetylase, promoted the acetylation of NF-κB p65, and subsequently activated its downstream NLRP3 inflammasome and IL-1β signaling.

Constipation due to Pi deficiency (Pi-xu) is a common Traditional Chinese Medicine (TCM) syndrome characterized by impaired Qi regulation and body fluid distribution disturbances from Pi deficiency. Polygonatum sibiricum and Poria cocos are representative medicine-food homology herbs traditionally used to fortify the Pi, nourish Yin, and regulate water metabolism. Their traditional functions are highly consistent with the pathogenesis of constipation due to Pi deficiency. This study explored the Polygonatum sibiricum and Poria cocos combination's potential and mechanisms for preventing constipation due to Pi deficiency. Mice were assigned to normal, model, and Polygonatum sibiricum and Poria cocos groups. General signs, fecal characteristics, gastrointestinal hormone levels (5-HT, CCK, MTL, and VIP), oxidative stress indicators (MDA and SOD), colonic histopathology, and gut microbiota profiles were evaluated. Compared with the model group, the combination significantly improved fecal properties and fecal water content (P < 0.05), reduced hepatic MDA levels, and increased SOD activity (P < 0.01). It also partially normalized gastrointestinal hormone imbalance and alleviated colonic mucosal damage. 16S rRNA sequencing revealed that the combination modulated gut microbiota composition and functional potential, characterized by reduced Proteobacteria abundance, enrichment of beneficial taxa with SFCA-producing potential, and preservation of core metabolic pathways. Correlation analysis suggested that gut microbiota modulation was closely associated with improvements in oxidative stress status, gut-brain axis-related factors, and intestinal barrier integrity. Overall, these findings indicate that the Polygonatum sibiricum and Poria cocos combination exerts preventive effects on constipation due to Pi deficiency through microbiota-mediated, multi-pathway regulation. This study provides experimental support for the TCM concept of "preventing disease before it arises" and highlights the potential of medicine-food homology products in preventive health strategies.