How does skeletal muscle adapt to reduce the possibility of damage by ROS?

At low ROS levels, they promote adaptation by increasing gene expression of antioxidant enzymes, such as Mn-SOD and Cu, Zn-SOD, CAT and GPX1 [94]. High antioxidant capacities then diminish the deleterious effects of subsequent increases in ROS [95].

What is the oxidative stress pathway?

Oxidative stress activates the MAPK signaling pathway. Activated ERK both positively and negatively regulates ROS levels indirectly via induction of p22phox, which increases ROS production, and activation of Nrf2, which upregulates antioxidants.

What is muscle oxidative stress?

Reactive oxygen species (ROSs) are often associated with damage to cellular functions. ROSs production is indicatives of oxidative stress during physical exercise. Oxidative stress occurs in those circumstances in which free radicals determine a tissue damage or production of toxic and dangerous compounds for tissues.

Are oxidative stress activated signaling pathways mediators of insulin resistance and β cell dysfunction?

In this review, we propose that ROS and oxidative stress induced by elevations in glucose and possibly FFA levels play a key role in causing insulin resistance and β-cell dysfunction by their ability to activate stress-sensitive signaling pathways (Fig. 1).

What is the primary ROS generated by skeletal muscle?

Mitochondria are commonly considered as the predominant source of ROS in skeletal muscle cells [6, 7]. Increased mitochondrial ROS generation occurs during various and different situations, such as in the course of intense contractile activity [8] or in response to cytokines such as tumor necrosis factor-α (TNF-α) [9].

What is the sarcopenia?

Sarcopenia is a syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength and it is strictly correlated with physical disability, poor quality of life and death. Risk factors for sarcopenia include age, gender and level of physical activity.

Does oxidative stress cause insulin resistance?

Oxidative stress is a fundamental problem of metabolic syndromes including type 2 diabetes. ROS cause insulin resistance in the peripheral tissues by affecting various points in insulin receptor signal transduction, ultimately resulting in decreased expression of GLUT4 transporter in the cellular membrane [57].

How are ROS generated in skeletal muscle?

During intense skeletal muscle contractile activity myotubes’ mitochondria generate high ROS flows: this renders skeletal muscle a tissue where ROS hold a particular relevance.