Increased desmin expression in hindlimb muscles of aging rats

Abstract

BackgroundAging skeletal muscle frequently exhibits a reduction in force produced per unit muscle tissue, variously termed muscle quality, specific tension or dynapenia. Muscles from animals in which desmin expression is reduced exhibit similar properties, raising the possibility that reduced desmin expression contributes to impaired force production in aging muscles.MethodsWe examined expression of desmin and synemin, both intermediate filament proteins, in the plantarflexor muscles of adult (6–8 months) and older (24 months) rats. We have previously reported age-related reductions in muscle quality and sarcoplasmic reticulum function in these animals.ResultsSignificant effects of age and muscle were found for the expression of desmin (P = 0.040 and <0.001 respectively), but not synemin. Desmin expression was increased in the aging muscles, with the greatest changes observed in the gastrocnemius muscles. Muscle quality, but not muscle mass, was reduced in the aging plantarflexor muscles.ConclusionsLoss of desmin does not account for reduced force production in aging muscles. The potential effects of the age-related increase in desmin on muscle function remain unclear, but may include dissipation of contractile force.

The Prophylactic Role of Vitamin E on the Alternations of Histology and Intermediate Filaments of Aged Rabbit cardiomyocytes

“…These findings agree with other studies which reported that aging process is always associated not only with the loss of myofilaments, but also with changes in the cytoskeletal intermediate filamentous proteins (Schaper et al, 1991;Hein et al, 1994;Russ and Grandy, 2011 cross-striations, may be the consequence of disorganization of the contractile material. Desmin scarcity and disorganization were especially evident in cells lacking contractile material.…”

“…It is widely accepted that aging is associated with a denervation-reinnervation process, and this may account for our observation of disorganized desmin intensity with aging. Therefore, the desmin augmentation found in the human myocardium was interpreted as a compensatory mechanism to ensure the cellular integrity and sarcomere stability (Russ and Grandy, 2011).…”

What is dynapenia?

“…However, more recent longitudinal data have failed to observe a direct relation between increased levels of intermuscular adipose tissue and strength loss with age [15]. Other compositional changes have also been speculated to potentially alter the intrinsic force-generating properties of aged skeletal muscle, such as changes in the ratio of myosin to actin [108], the functional interaction of actin and myosin proteins [109-111], the expression of the thin filament regulatory proteins troponin and tropomyosin [112], and/or the expression of cytoskeletal proteins [113]. However, currently little attention has been paid to these potential contributors as they relates to dynapenia, and further work is needed to better delineate their relative contributions.…”

“…Theoretically speaking, the disruption of any of the events in the excitation–contraction coupling process could result in the suboptimal activation of muscle, thus decreasing muscle quality (force per unit tissue area), and contribute to dynapenia. In particular, impairments in calcium (Ca 2+ ) release from the sarcoplasmic reticulum have been suggested to explain the deficits of muscle quality (the intrinsic force-generating capacity of skeletal muscle relative to its tissue size) in aged muscle [113-123]. The effects of aging on the principal proteins involved in voltage-induced Ca 2+ release (e.g., ryanodine Y receptors and dihydropyridine receptors) have received the most scientific attention.…”

Highlights of the mechanistic and therapeutic cachexia and sarcopenia research 2010 to 2012 and their relevance for cardiology

“…Other pathogenetic factors studied include sirtuin 1, which has been suggested to be a relevant mechanistic factor in the development of insufficient regeneration of skeletal muscle in cancer cachexia [55]. Desmin and tissue zinc redistribution are additional factors investigated for their role in muscle wasting [56,57]. Other important fields of research are related to metabolic syndrome and insulin resistance [58][59][60][61] as well as heat shock protein 72 [62] and muscle stem cell function [63] and related telomere alterations [64].…”