Desmin degradation in the skeletal muscle of patients with chronic critical illness

Abstract

Critical illness myopathy (CIM) is a primary myopathy that develops in critically ill patients. Histologic features of CIM include a general decrease in muscle fiber cross-sectional area and a predominant loss of the motor protein myosin. These features are observed in the absence of inflammatory infiltrates but with detectable cytokine activation. The purpose of this study was to examine the state of the extracellular matrix of the human soleus muscle under conditions of CIM caused by chronic impairment of consciousness. Incisional muscle biopsies were taken from the soleus muscle of 6 patients who were in a chronic critical condition and were treated in the Department of Anesthesiology and Reanimation at the A.L. Polenov Russian Research Institute - branch of the Almazov National Medical Research Center. The study included patients with a chronic impairment of consciousness lasting at least 2 months. Muscle biopsies taken from healthy men were used as controls. The biopsies were obtained using needle biopsy under local anesthesia. Using histological staining of tissue sections, it was determined that patients with CIM exhibited a significant increase in collagen area, surpassing the control value by 82%. An increased mRNA content of collagens I, III, and VIa was also observed, along with an increase in the protein content of collagen I and III. At the same time, we did not observe any changes in the content of fibronectin and extracellular tissue growth factor mRNA. However, we did observe an increase in the mRNA of the integrin A7 subunit. The results obtained indicate significant skeletal muscle fibrosis under CIM conditions. Further studies on the signaling pathways that regulate this process are needed.