Rapid Induction of Meningeal Collagen Synthesis in the Cerebral Cisternal and Ventricular Compartments after Subarachnoid Hemorrhage

Summary.

Procollagen propeptides in the lumbar CSF increase after subarachnoid hemorrhage (SAH), and elevated concentrations have been detected as early as on day 8. We studied here the timing and localization of the induction of meningeal collagen synthesis during the first week after SAH by analysing cisternal and ventricular CSF samples. We obtained 29 cisternal and 10 ventricular CSF samples at operation from patients with SAH between days 1 and 9 after onset. The carboxyterminal propeptide of type I procollagen (PICP) and the aminoterminal propeptide of type III procollagen (PIIINP) were measured using radio-immunoassays. The concentrations of PICP and PIIINP in the cisternal CSF were elevated as early as on day 2 after SAH. PICP increased in a sigmoidal fashion (R²=0.39, p<0.001), while PIIINP increased linearly (R²=0.28, p=0.003) and was approximately 3-fold higher on day 9 than initially. PICP was twice as high (p=0.02) in the cisternal than in the ventricular CSF after SAH and PIIINP was 4-times higher (p=0.007). Interestingly, the concentrations were similar in a patient with intraventricular bleeding. The cisternal compartment contributed to the propeptides in the CSF more than did the ventricular compartment, but the latter also appeared to have a definite potential for fibroproliferative reaction. Meningeal collagen synthesis was induced rapidly within the first few days after SAH suggesting that therapeutic attempts to inhibit the fibroproliferative reaction should be started as early as possible.