Microbiota and Aging.

The human gut microbiota is a huge ecosystem that provides lots of functions for host development, immune system, and metabolism. Gut microbiota is linked to lots of diseases, including human metabolic diseases such as obesity, type 2 diabetes (T2D), irritable bowel syndrome, and cardiovascular disease (CVD). Few studies, however, have noted the relationship between aging and microbiota; the connection between aging and microbiota remains largely to be researched. In this review, recent research findings are summarized on the role of gut microbiota in aging processes with emphasis on therapeutic potential of microbiome-targeted interventions in antiaging medicine.

Correction to: Microbiota and Aging.

The original version of the chapter was inadvertently published without an acknowledgement details. The acknowledgements section has now been updated with the below text.

Calorie intake rather than food quantity consumed is the key factor for the anti-aging effect of calorie restriction.

Although calorie restriction has been reported to extend lifespan in several organisms, animals subjected to calorie restriction consume not only fewer calories but also smaller quantities of food. Whether it is the overall restriction of calories or the coincidental reduction in the quantity of food consumed that mediates the anti-aging effects is unclear. Here, we subjected mice to five dietary interventions. We showed that both calorie and quantity restriction could improve early survival, but no maximum lifespan extension was observed in the mice fed isocaloric diet in which food quantity was reduced. Mice fed isoquant diet with fewer calories showed maximum lifespan extension and improved health among all the groups, suggesting that calorie intake rather than food quantity consumed is the key factor for the anti-aging effect of calorie restriction. Midlife liver gene expression correlations with lifespan revealed that calorie restriction raised fatty acid biosynthesis and metabolism and biosynthesis of amino acids but inhibited carbon metabolism, indicating different effects on fatty acid metabolism and carbohydrate metabolism. Our data illustrate the effects of calories and food quantity on the lifespan extension by calorie restriction and their potential mechanisms, which will provide guidance on the application of calorie restriction to humans.

Calorie restriction is the most reasonable anti-ageing intervention: a meta-analysis of survival curves.

Despite technological advances, the survival records from longevity experiments remain the most indispensable tool in ageing-related research. A variety of interventions, including medications, genetic manipulations and calorie restriction (CR), have been demonstrated to extend the lifespan of several species. Surprisingly, few systematic studies have investigated the differences among these anti-ageing strategies using survival data. Here, we conduct a comprehensive and comparative meta-analysis of numerous published studies on Caenorhabditis elegans and Drosophila. We found that CR and genetic manipulations are generally more effective than medications at extending the total lifespan in both models, and CR can improve the ageing pattern of C. elegans. We further analysed the survival variation for different anti-ageing medications and determined that hypoglycaemic agents and antioxidants are advantageous despite only moderately increasing the overall lifespan; therefore, these two types of medications are promising CR mimetics. Analysis of genetic manipulations also indicated that the genes or pathways that extend lifespan in a healthier pattern are associated with CR. These results suggest that CR or CR mimetics may be the most reasonable and potentially beneficial anti-ageing strategy.

Calorie restriction-induced SIRT6 activation delays aging by suppressing NF-κB signaling.

Calorie restriction (CR) extends lifespan from yeast to mammals. SIRT6 is a member of the sirtuin family of NAD(+)-dependent histone deacetylases, which is responsible for mediating the effects of CR. The transcription factor NF-κB, which is involved in inflammation and aging, has been shown to be regulated by SIRT6. Here we describe the crucial role of SIRT6 in aging and inflammation. We show that CR had improved renal insufficiency and enhanced SIRT6 expression after 6-month treatment in aged mice. Culture cells in low glucose (LG) conditions also showed resistance to cell senescence and enhanced SIRT6 expression compared to normal glucose (NG) group, showing beneficial effects of the CR-mimic cultural conditions. Moreover, SIRT6 overexpression is sufficient to delay the replicative senescence of WI38 by attenuating NF-κB signaling, while SIRT6 knockdown results in accelerated cell senescence and overactive NF-κB signaling. These findings confirm the key status of CR and disclose the critical role of SIRT6 on aging and inflammation.