Age-dependent changes in the gut microbiota and serum metabolome correlate with renal function and human aging.

Human aging is invariably accompanied by a decline in renal function, a process potentially exacerbated by uremic toxins originating from gut microbes. Based on a registered household Chinese Guangxi longevity cohort (n = 151), we conducted comprehensive profiling of the gut microbiota and serum metabolome of individuals from 22 to 111 years of age and validated the findings in two independent East Asian aging cohorts (Japan aging cohort n = 330, Yunnan aging cohort n = 80), identifying unique age-dependent differences in the microbiota and serum metabolome. We discovered that the influence of the gut microbiota on serum metabolites intensifies with advancing age. Furthermore, mediation analyses unveiled putative causal relationships between the gut microbiota (Escherichia coli, Odoribacter splanchnicus, and Desulfovibrio piger) and serum metabolite markers related to impaired renal function (p-cresol, N-phenylacetylglutamine, 2-oxindole, and 4-aminohippuric acid) and aging. The fecal microbiota transplantation experiment demonstrated that the feces of elderly individuals could influence markers related to impaired renal function in the serum. Our findings reveal novel links between age-dependent alterations in the gut microbiota and serum metabolite markers of impaired renal function, providing novel insights into the effects of microbiota-metabolite interplay on renal function and healthy aging.

Serum branched-chain amino acids are associated with leukocyte telomere length and frailty based on residents from Guangxi longevity county.

Branched-chain amino acids (BCAAs) and telomere length are biologically associated with healthy aging. However, the association between them and their interaction on frailty remain unclear in humans. Here, a cross-sectional study based on residents from Guangxi longevity county was conducted to investigate the association of serum BCAAs, peripheral leukocyte telomere length (LTL) and frailty. A total of 1,034 subjects aged 20 to 110 years were recruited in the study. The real-time qPCR method and a targeted metabolomics approach based on isotope dilution liquid chromatography tandem mass spectrometry (LC/MS/MS) method were used for measurement of LTL and BCAAs, respectively. A frailty score defined as the proportion of accumulated deficits based on 24 aging-related items was used assess the health status of elderly subjects. First, we found that a higher concentration of BCAAs was significantly associated with longer LTL only in middle-aged subjects, independent of age and BMI (P < 0.05). In the oldest-old subjects, we identified a significantly inverse association between BCAAs and frailty score (P < 0.001), even after adjustment for age and BMI (P < 0.05). Additionally, we recognized a statistically significant synergetic interaction between BCAAs and LTL on frailty score in the oldest-old subjects by the general linear model (P = 0.042), although we did not find any significant association between LTL and frailty score. In summary, our findings suggest a potentially protective effect of circulating BCAAs on LTL and frailty based on the subjects from longevity county in East Asia and indicate a potential synergetic interaction between BCAAs and LTL in healthy aging.