Osmolytes as Mediators of the Muscle Tissue’s Responses to Inflammation: Emerging Regulators of Myositis with Therapeutic Potential

Chronic inflammation of skeletal muscle tissues, termed myositis, is associated with inherited muscular dystrophy and acquired inflammatory myopathy. In this review, the role of the organic osmolytes taurine, betaine, myo-inositol, and sorbitol in skeletal muscles in general, and in myositis in particular, is discussed. Evidence indicates that regulated osmolyte pathway activation contributes to normal muscle functioning, which becomes further activated in myositis as part of the tissue’s programme of damage control. On the one hand, osmolytes seem to act as protein stabilisers in muscle fibres counteracting tissue injury but, on the other hand, these compounds also regulate immune cell function. The possibilities for treating myositis through boosting of beneficial or targeting of adversary effects are explored.