Extracellular Matrix Alterations in Human Soleus Muscle under Conditions of Chronic Disorder of Consciousness

Critical illness myopathy (CIM) is a primary myopathy thatdevelops in critically ill patients. Histological features of CIMinclude a general reduction in muscle fiber cross-sectional areaand a predominant loss of the motor protein myosin in the absenceof inflammatory infiltrates but with detectable cytokine activation.This study was aimed to examine the state of the soleus muscle extracellularmatrix in patients with CIM caused by chronic disorders of consciousness.Incisional needle biopsies of the soleus muscle were taken from6 patients with a chronic (≥ 2 months) disorder of consciousness,undergoing treatment at the Polenov Neurosurgical Institute (AlmazovNational Medical Research Center, St. Petersburg), and healthy men(control). Histological staining of soleus muscle sections in patientswith CIM revealed a significantly increased collagen area that exceededcontrol values by 82%. Type I, III and VIa collagen mRNA levels,along with type I and III collagen content, were increased. No changeswere found in fibronectin and extracellular tissue growth factormRNA levels. However, integrin α7 mRNA levels were elevated. Ourresults indicate significant skeletal muscle fibrosis in CIM, requiringfurther studies on the signaling pathways that regulate this process.