Circulating levels of adipokines and IGF-1 are associated with skeletal muscle strength of young and old healthy subjects

Abstract

It is known that adipose tissue mass increases with age, and that a number of hormones, collectively called adipokines, are produced by adipose tissue. For most of them it is not known whether their plasmatic levels change with age. Moreover, it is known that adipose tissue infiltration in skeletal muscle is related to sarcopenia and loss of muscle strength. In this study we investigated the age-related changes of representative adipokines and insulin-like growth factor (IGF)-1 and their effect on muscle strength. We studied the association between circulating levels of adiponectin, leptin, resistin and IGF-1 and muscle strength. This cross-sectional study included 412 subjects of different age (152 subjects aged 18-30 years and 260 subjects aged 69-81 years) recruited within the framework of the European research network project "Myoage". The levels of adiponectin (both in male and female subjects) and leptin (only in males) were significantly higher in old subjects compared to young, while those of IGF-1 were lower in old subjects. In old subjects adiponectin, resistin and the resistin/IGF-1 ratio (but not IGF-1 alone) were inversely associated with quadriceps torque, while only adiponectin was inversely associated with handgrip strength independently from percentage of fat mass, height, age, gender and geographical origin. The ratio of leptin to adiponectin was directly associated with handgrip strength in both young and old subjects. These results suggest that in humans the age-associated loss of strength is associated with the levels of representative adipokines and IGF-1.

Characterization of adiponectin concentrations and molecular weight forms in serum, seminal plasma, and ovarian follicular fluid from cattle

“…The increase of AdipoQ concentrations in the serum with age for bulls is consistent with observations in aging humans [31,32]. In men, this age-related increase of serum AdipoQ concentration is more pronounced than in women.…”

Benefits of High-Intensity Exercise Training to Patients with Chronic Obstructive Pulmonary Disease: A Controlled Study

“…In contrast, resistin is linked to inflammation and senescence. For example, the results from a cross-sectional study which included 412 subjects of different ages revealed that in old subjects resistin is inversely associated with muscle strength [37] . In older adults, higher resistin levels have also been found to be associated with cardiovascular events [38] .…”

Cross-sectional associations between different measures of obesity and muscle strength in men and women in a British cohort study

“…These effects increase skeletal muscle insulin resistance, an important factor in the development of type II diabetes, and demonstrate the close link between the metabolic functions of central adipose tissue and skeletal muscle. Considering adiponectin, leptin and resistin concentrations have also been associated with muscle strength (38) it is plausible that with central obesity and changes in the metabolic function of skeletal muscle, its mechanical function also changes.…”

“…Greater variation in muscle mass amongst men may contribute to the larger differences in grip strength by BMI category, but the smaller differences in grip strength with increasing WC in women are difficult to explain. Differences in the levels of adipokines in men compared to women have been reported, along with differential associations with muscle parameters (38). However, much remains to be elucidated regarding the interplay of adipokines, inflammatory mediators and traditional endocrine factors such as levels of anabolic hormones.…”