Meningeal protein synthesis in chronic subdural hemorrhagies. Analysis of proteins and evaluation of their clinical significance

Chronic subdural hematoma (CSDH) is a common disease in neurosurgical practice affecting mainly elderly people. CSDH grows slowly within the meningeal dural border cell (DBC) layer, which may be cleaved open e.g. during trivial head injury. Inflammatory mechanisms involving the dura mater have an acknowledged role in the pathogenesis of CSDH. In this study, we aimed to evaluate the contribution of meningeal extracellular matrix synthesis, namely collagen and glycosaminoglycans, in slowly growing chronic subdural collections after head injury. The protein content of CSDH fluid was characterized in order to evaluate proteins putatively involved in CSDH pathogenesis. We found that CSDH fluid proteins originate mainly from blood as CSDH fluid and serum proteins show high similarity. Still, a few proteins with a potential role in CSDH pathogenesis were detected in CSDH fluid. The results indicate that meningeal ECM synthesis is induced after cleavage of the DBC layer. E.g., high concentrations of procollagen propeptides were found in subdural fluid samples as a sign of sustained dural collagen synthesis after cleavage of the DBC layer. Glycosaminoglycans may participate in the reactive process. Inflammation and fibrosis remain as targets for further studies in the pathogenesis of CSDH.