gms | German Medical Science

Objective: Delayed vasospasm after rupture of intracranial aneurysm is the main cause for severe neurological deficits and death. The presence of subarachnoid blood induces an inflammatory reaction resulting in vasospasm with brain ische-mia. Until now little is known about the inflammatory cascade and the substances starting and triggering the inflammatory reaction. MRP14, a calcium binding pro-tein expressed from neutrophils and macrophages, plays an essential role in the acute phase of inflammation, as adhesion of inflammatory cells and migration. Aim of this study was to determine the role of MRP14 in pathogenesis of cerebral vasospasm after subarachnoid haemorrhage (SAH).

Methods: Samples of cerebrospinal fluid (CSF) in patients with SAH as well as of controls (myelography) were attained via ventricular or lumbar drainage, in controls via lumbar puncture. CSF was centrifuged and stored at –80°C. All laboratory examinations were blinded. Human cerebral arteries were fixed in 4% formalin for 24 h, dehydrated and paraffin-embedded. Sections (10 µm) were fixed in acetone for 10 min at room temperature and washed in PBS. Endogenous peroxidase activity was blocked by incubating the preparations in natriumacid (Sigma) diluted at 1g/150ml PBS plus H₂O₂ for 20 min at room tem-perature. PBS/1% BSA was used to block non-specific binding for 60 min. Prepa-rations were stained with primary antibody, followed by incubation with peroxi-dase-conjugated goat anti rat or anti rabbit IgG in PBS/1% BSA/20% inactivated mouse serum for 60 min. Enzymatic colour development was preformed using 3-amino-9 ethylcarbazole as substrate diluted in acetate buffer with H₂O₂ at 37°C for 12 min. Slides were then counterstained with Giemsa and mounted with mounting Medium Aquamount (BDH).

Results: MRP14 concentration in cerebrospinal fluid (CSF) of controls were not detectable (n=5) whereas MRP14 in all patients with SAH and documented clini-cal vasospasm were positive (n=6) in CSF as well as in blood. In CSF of a pa-tient with SAH the MRP14 level amounts of about 18000 ng/ml. Immunoreactivity of MRP14 in brain sections (predominantly in vessel walls) corresponded to CSF values of MRP14 in patients with SAH.

Conclusions: These first results suggest that MRP14 is a key protein involved in the early phase of inflammation after SAH. Further investigations must reveal if an elevated MRP14 protein concentration in blood and/or CSF can predict the occurrence of vasospasm after SAH.