Age related gut microbiota regulates energy-related metabolism to influence natural aging phenotypes in the heart

As the population ages, problems pertaining to health and life expectancy due to the aging heart have become increasingly prominent. The gut microbiota has become a potential therapeutic target in several diseases, including cardiovascular diseases. Current studies on the roles of the gut microbiota in the cardiovascular system have focused mainly on cardiovascular diseases; therefore, the effects of the gut microbiota on the natural aging of myocardial tissue remain unclear. The present study aimed to explore the roles and mechanisms of the gut microbiota and related metabolites in the natural aging of the heart. Animal models of fecal microbiota transplantation (FMT) were established in elderly and young rats. 16S rRNA sequencing revealed that the gut microbiota of the recipients shifted toward the profile of the donors, with concomitant cardiac structure and diastolic function changes detected via ultrasound and positron emission tomography-computed tomography (PET-CT). A group of significantly enriched myocardial metabolites detected by LC/MS were involved in the fatty acid β-oxidation process. Together with altered glucose uptake, as revealed by PET-CT, changes in ATP content and mitochondrial structure further verified a metabolic difference related to energy among rats transplanted with the gut microbiota from donors of different ages. This study demonstrated that gut microbes may participate in the physiological aging process of the rat heart by regulating oxidative stress and autophagy. The gut microbiota has been shown to be involved in the natural aging of the heart at multiple levels, from the organ level to the metabolically plastic myocardiocytes and associated molecules.