A potential probiotic bacterium for antipsychotic-induced metabolic syndrome: mechanisms underpinning how Akkermansia muciniphila subtype improves olanzapine-induced glucose homeostasis in mice.

BACKGROUND: Olanzapine (OLZ) is one of the most effective atypical antipsychotics but is associated with severe metabolic side effects, in which the gut microbiota plays an important role. Akkermansia muciniphila (A. muciniphila; Akk), a Gram-negative anaerobic bacterium in the intestine, can potentially improve metabolic syndrome. OBJECTIVE: This study investigated the effect and underlying mechanisms of an A. muciniphila subtype (A. muciniphilasub; Akksub) on OLZ-induced metabolic dysfunction in lean and obese mice. METHODS: C57BL/6 female mice were fed a high-fat diet to induce obesity or normal chow for 8 weeks before OLZ treatment for 16 weeks. During the treatment period, mice in each group were orally administrated A. muciniphilasub. Weight gain, glucose and lipid metabolism, and inflammation were evaluated. RESULTS: A. muciniphilasub decreased OLZ-related weight gain only at week 16 in lean mice and significantly alleviated OLZ-induced hyperglycemia irrespective of diet. This was accompanied by reduced levels of glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK)-key enzymes in hepatic gluconeogenesis-and OLZ-associated insulin resistance. Moreover, OLZ-induced increases in serum interleukin (IL)-6 and tumor necrosis factor (TNF)-α levels were improved by A. muciniphilasub in both obese and lean mice. OLZ did not increase serum lipid levels or hepatic fat accumulation. CONCLUSIONS: A. muciniphilasub improves OLZ-related hyperglycemia via regulation of G6Pase and PEPCK levels and insulin resistance. Moreover, A. muciniphilasub alleviates systemic inflammation caused by OLZ. A. muciniphilasub is a promising probiotic treatment for OLZ-induced metabolic dysfunction.

Diverse effects of different Akkermansia muciniphila genotypes on Brown adipose tissue inflammation and whitening in a high-fat-diet murine model.

BACKGROUND: The purpose of this study was to investigate the differences in the metabolic protective effects of Akkermansia muciniphila (A.muciniphila) genotypes on high-fat diet mice and explore possible mechanisms. METHODS: Male C57BL/6 mice were randomly divided into 6 groups, including high-fat diet (HFD)+ A. muciniphila I/II/PBS group, normal control diet (NCD)+ A. muciniphila I/II/PBS group, respectively. Dietary intervention and A. muciniphila gavage were performed simultaneously. Blood glucose and lipid metabolism, brown adipose morphology and activities, and intestinal barrier function were examined after the mice were sacrificed. RESULTS: A.muciniphila gavage improved the impaired glucose tolerance, hyperlipidemia and liver steatosis in HFD mice, and that A. muciniphila II (Amuc_GP25) was not as effective as A. muciniphila I (Amuc_GP01). This phenomenon might be because Amuc_GP01 intervention significantly inhibited brown adipose tissue whitening and inflammation induced by HFD, by repairing the intestinal barrier and relieving endotoxemia. Amuc_GP25 did not display the same results as Amuc_GP01 in HFD mice but had stronger effects in the NCD mice. CONCLUSIONS: This study reveals the distinct functions of different A. muciniphila genotypes on diet-induced obesity, suggesting that different A. muciniphila genotypes may affect pathological conditions differently through distinct action pathways.