Subsarcolemmal and intermyofibrillar mitochondria proteome differences disclose functional specializations in skeletal muscle.

Skeletal muscle is a highly specialized tissue that contains two distinct mitochondria subpopulations, the subsarcolemmal (SS) and the intermyofibrillar (IMF) mitochondria. Although it is established that these mitochondrial subpopulations differ functionally in several ways, limited information exists about the proteomic differences underlying these functional differences. Therefore, the objective of this study was to biochemically characterize the SS and IMF mitochondria isolated from rat red gastrocnemius skeletal muscle.

Proteolysis activation and proteome alterations in murine skeletal muscle submitted to 1 week of hindlimb suspension.

The aim of this study was to investigate the temporal involvement of different proteolytic systems and muscle proteome changes during experimental disuse atrophy (up to 1 week hindlimb suspension, HS) in murine gastrocnemius muscle. The results showed that proteolysis, cytoprotection mechanisms and signs of cellular infiltration occurred very early. After 1 day of HS, signals of lysosomal activation, rather than programmed cell death (apoptosis), seem to trigger protein breakdown in the whole skeletal muscle.

Influence of knee flexion on plantarflexion moments after open or percutaneous Achilles tendon repair.

Background: The influence of the knee angle on plantarflexion moments after Achilles tendon repair has yet to be analyzed. It was hypothesized that flexion of the knee joint will disproportionately influence isometric plantarflexion moments after Achilles tendon repair.

Materials And Methods: Isometric plantarflexion moments and functional heel rise performance were retrospectively assessed in 32 patients at a mean follow-up of 36.

Aging impairs skeletal muscle mitochondrial bioenergetic function.

This study investigated the influence of age on the functional status of mitochondria isolated from skeletal muscle of C57BL/6 mice aged 3 and 18 months. We hypothesized that skeletal muscle mitochondria isolated from aged animals will exhibit a decreased respiratory function. Mitochondrial respiratory functional measures (ie, State 3 and 4 respiration, respiratory control ratio and number of nanomoles of ADP phosphorylated by nanomoles of O(2) consumed per mitochondrion) and biochemical markers of oxidative damage (aconitase activity, protein carbonyl derivatives, sulfhydryl groups, and malondialdehyde) were measured in isolated mitochondrial suspensions.

Age-induced morphological, biochemical, and functional alterations in isolated mitochondria from murine skeletal muscle.

Several in vitro studies about age-associated skeletal muscle mitochondrial dysfunction are somewhat conflicting, and this might be related to different normalization procedures. The objective of this study was to normalize the functional and biochemical data per number of mitochondria present in a mitochondrial suspension. Functional and biochemical parameters were obtained in mitochondrial suspensions from murine skeletal muscle of different ages.

The role of mitochondria in aging of skeletal muscle.

Aging can be characterized as a time dependent decline of maximal functionality that affects tissues and organs of the whole body. Such is induced by the progressive loss of redundant components and leads to an increased susceptibility to disease and risk of death. Regarding the aging of skeletal muscle, it has been pointed out that mitochondria is a key factor behind the loss of redundancy and functionality, since this organelle has a major role in cellular homeostasis particularly at the level of the bioenergetic status.

Cellular patterns of the atrophic response in murine soleus and gastrocnemius muscles submitted to simulated weightlessness.

The purpose of the present study was to investigate the mechanisms of cell death (apoptosis vs. necrosis) during muscle atrophy induced by 1 week of hindlimb suspension. Biochemical and morphological parameters were examined in murine soleus and gastrocnemius muscles.