Age-related obesity is a heritage of the evolutionary past

Age‐related features of the content of substrates of energy metabolism and body mass index in women residing in the S ubarctic and A rctic regions of R ussia

OBJECTIVES

Age is associated with a number of health risks linked to obesity caused by an imbalance in the main energy substrates-fatty acids (FA) and glucose (Glu). Therefore, the objective of this study was to identify age-related features of the metabolism of fatty acids and Glu, their correlations and the relation with the body mass index (BMI) in women of the local Caucasoid population from two northern regions of Russia with different nature, climate, and geography.

METHODS

We examined women aged 21-60 years born and permanently residing in the Subarctic region (SR) and the Arctic region (AR). The participants were divided into three age groups: 21-35, 36-45, and 46-60 years. The levels of FAs, Glu, and triglycerides (TG) in the blood serum were determined by spectrophotometric and gas chromatographic methods; the values of BMI and TyG (triglyceride glucose) index were calculated. To analyze data, we used the descriptive and correlation analyses by nonparametric methods, as well as multiple linear regression analysis.

RESULTS

With age, the surveyed women demonstrated elevated levels of triglyceride, the majority of the studied fatty acids, BMI and TyG index. For three fatty acids, age-related changes were noted in one of the regions only: stearic and linoleic acids in the SR, and docosahexaenoic acid in the AR; no significant changes were observed for dihomo-γ-linolenic and arachidonic acids. We found elevated Glu levels in women aged 46-60 years residing in the SR. Regional differences were due to higher concentrations of FAs and Glu in the AR. All identified correlations were positive. BMI values were associated with FAs and TG, and in women aged 46-60 years, they were additionally associated with Glu. The latter also correlated with some FAs and TG in this group. TyG index associations with saturated FAs (SFAs) became stronger with age.

CONCLUSIONS

Age has a significant impact on the homeostasis of key energy substrates (Glu, TG, SFAs, monounsaturated FAs), on BMI and TyG index, which are indicators of obesity and insulin resistance. Depending on the region of residence (Subarctic or Arctic), we found changes in the FA profile undersaturation (especially long-chain polyunsaturated FAs) and some specific features of Glu homeostasis (for the age groups of 21-35 and 46-60 years) in women of Caucasoid race in the Russian North. Multiple regression analysis showed that BMI, as well as the region of residence and age, are significant predictors for almost all biochemical parameters, especially for TG and TyG index.

Dysregulated Autophagy Mediates Sarcopenic Obesity and Its Complications via AMPK and PGC1α Signaling Pathways: Potential Involvement of Gut Dysbiosis as a Pathological Link

Sarcopenic obesity (SOB), which is closely related to being elderly as a feature of aging, is recently gaining attention because it is associated with many other age-related diseases that present as altered intercellular communication, dysregulated nutrient sensing, and mitochondrial dysfunction. Along with insulin resistance and inflammation as the core pathogenesis of SOB, autophagy has recently gained attention as a significant mechanism of muscle aging in SOB. Known as important cellular metabolic regulators, the AMP-activated protein kinase (AMPK) and the peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1α) signaling pathways play an important role in autophagy, inflammation, and insulin resistance, as well as mutual communication between skeletal muscle, adipose tissue, and the liver. Furthermore, AMPK and PGC-1α signaling pathways are implicated in the gut microbiome-muscle axis. In this review, we describe the pathological link between SOB and its associated complications such as metabolic, cardiovascular, and liver disease, falls and fractures, osteoarthritis, pulmonary disease, and mental health via dysregulated autophagy controlled by AMPK and/or PGC-1α signaling pathways. Here, we propose potential treatments for SOB by modulating autophagy activity and gut dysbiosis based on plausible pathological links.