Leptin in Sarcopenic Visceral Obesity: Possible Link between Adipocytes and Myocytes

Abstract

The combination of sarcopenia, age-related loss of muscle strength and mass, and obesity has been recognized as a new category of obesity among the elderly. Given that leptin has been hypothesized to be involved in the pathogenesis of sarcopenic obesity, we investigated the relationship between plasma leptin levels and thigh muscle sarcopenia and visceral obesity. Thigh muscle cross-sectional area (CSA) and visceral fat area were measured using computed tomography as indices for muscle mass and visceral fat, respectively, in 782 middle-aged to elderly subjects (303 men and 479 women), participating in a medical check-up program. Visceral obesity was defined as visceral fat area >100 cm2, and sarcopenia was defined as < (one standard deviation − mean of thigh muscle CSA/body weight of young subjects [aged <50 years]).Thigh muscle CSA was significantly and negatively associated with plasma levels of leptin in both men (β = -0.28, p<0.0001) and women (β = -0.20, p<0.0001), even after correcting for other confounding parameters, including age, body weight, body height, visceral fat area, blood pressure, homeostatic model assessment index, and high sensitive C reactive protein. Subjects were divided into four groups based on presence or absence of sarcopenia or visceral obesity. Plasma levels of leptin were higher in subjects with sarcopenic visceral obesity than in those with either sarcopenia or visceral obesity alone. These findings indicate that sarcopenic visceral obesity is a more advanced, and suggest that leptin may link visceral obesity and sarcopenia.

Association between sarcopenic obesity and cardiovascular risk: where are we?

“…In obese subjects, serum leptin levels increase with fat deposition diminishing its beneficial effect in skeletal muscle (3). Studies show that individuals with SO have higher serum leptin levels when compared to obese, sarcopenic or control groups (3,12,19). Serum leptin levels also correlated negatively with the MM indicators and positively with the AT indicators (3,19).…”

“…Besides the inflammatory process and insulin resistance, leptin is highlighted in the physiopathology of SO. It is secreted by adipocytes and has physiologic and physiopathologic actions in several organs, including skeletal muscle where it acts stimulating lipolysis and insulin sensitivity (3,32). The leptin receptors have been shown to be negatively regulated by leptin itself and by insulin resistance.…”

“…The leptin receptors have been shown to be negatively regulated by leptin itself and by insulin resistance. In obese subjects, serum leptin levels increase with fat deposition diminishing its beneficial effect in skeletal muscle (3). Studies show that individuals with SO have higher serum leptin levels when compared to obese, sarcopenic or control groups (3,12,19).…”

“…The main changes of BC are related to excess of adipose tissue (AT) and/or the deficit of muscular mass (MM), defined as obesity, sarcopenia or sarcopenic obesity (SO), when both conditions appear simultaneously (1). The prevalence of SO has increased in industrialized countries due to the high number of cases of obesity and sarcopenia in obese people, ranging from 4.4% to 42.9%, depending on the diagnostic methods and on the studied population (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). There is not a consensus between the definition and classification of SO, and this gap contributes to the inconsistent findings in its association with clinical outcomes (22)(23)(24).…”

Conceptos básicos sobre obesidad sarcopénica en el adulto mayor

“…En el caso del factor nutricional, el déficit de vitamina D se ha correlacionado con el proceso de cambio de composición corporal. (15,(19)(20)(21)(22)(23) Además la pérdida fuerza muscular es hasta 3 veces mayor que la pérdida de masa muscular; a nivel neurológicohay cambios desde la vía piramidal hasta la composición tendinosa y cambios postraduccionales en las cadenas de miosina (19,21) . El tejido graso actúa como determinante funcional en las distintas etapas de la vida.…”