Fulvio Tartara

Cisternal CSF levels of cytokines after subarachnoid hemorrhage.

Cytokines are considered as mediators of immune and inflammatory responses. Cisternal CSF levels of interleukin (IL)-6, IL-8, monocyte chemoattractant protein-1 (MCP-1) and of the soluble adhesion molecule E-selectin were evaluated in patients operated on for intracranial aneurysms. Cisternal CSF samples were obtained at surgery in 41 selected patients (31 with diagnosis of subarachnoid hemorrhage (SAH) and 10 control patients operated on for incidental unruptured aneurysms); 14 patients were operated within 72 h after SAH (early surgery) and 17 were operated after day 10 after the hemorrhage (delayed surgery). The CSF levels of cytokines were evaluated using radioimmunoassay and their concentrations were related to the timing of surgery, the amount of cisternal subarachnoid blood clots and the onset of clinical and angiographical evidence of arterial vasospasm. Mean cisternal CSF levels of IL-6, IL-8 and AMCP-1 are significantly higher in samples obtained from patients early operated after SAH, while levels of E-selectin were below the threshold value of the method in all 41 cases. In the early operated group 7 patients presented symptomatic vasospasm: levels of IL-8 and MCP-1 were not significantly different were compared to those of uncomplicated cases; on the other hand, significantly higher levels of IL-6 were shown in the subgroup of patients operated within 72 h after SAH and developing vasospasm. Among the patients undergoing delayed surgery 5 presented symptomatic vasospasm, but no significant difference was shown in cisternal CSF levels of cytokines measured. The results of the present study show that in patients with unruptured aneurysms cytokines are present in cisternal CSF in scarce quantities and that in subarachnoid spaces after SAH there is an impressive increase of IL-6, IL-8 and MCP-1. Moreover, the higher cisternal CSF levels of IL-6 found in the early stage after SAH might have a predictive value regarding the occurrence of symptomatic vasospasm.

Metalloproteases and intracranial vascular lesions

Recent studies have suggested that metalloproteinases (MMP) might be involved in the pathogenesis of cerebral aneurysm formation and rupture and that elevated serum levels of MMP may effectively be considered as possible markers of cerebrovascular malformations. The present study was planned in order to verify if serum levels of MMPs may be the mirror of the MMP activity in the wall of intracranial aneurysms, reflecting the predisposition to aneurysm development and/or rupture. A series of 84 patients operated for intracranial cerebrovascular lesions (63 aneurysms and 21 arterovenous malformations (AVM)) and 20 controls entered the study. Among the 63 cases of intracranial aneurysms, nine were discovered before rupture, while 54 patients were included after subarachnoid hemorrhage (SAH). Using radioimmunoassay, plasma elastase levels were measured in all cases, while in 25 cases, when aneurysmectomy was possible, the activity of elastase and collagenase were measured in aneurysm samples. Mean plasma elastase level in patients bearing both an intracranial aneurysm or an intracranial AVM was significantly higher than in controls, while there was no significant difference between plasmatic level of elastase in patients with aneurysms when compared with patients bearing an intracranial AVM; there was no significant difference between mean elastase level in patients who suffered SAH and patients bearing an intracranial unruptured aneurysm. The activity of elastase and collagenase measured in the aneurysm wall were significantly higher in cases of ruptured than in unruptured aneurysms. The present results show that plasmatic level of elastase does not reflect the activity of MMP as measured in the aneurysm wall and that the patterns of MMP activities measured in the aneurysm wall differ considerably at different stages of SAH. This suggests that local rather than systemic changes in metalloproteases activity might be involved in cerebral aneurysm formation and rupture.

Activity of α1-antitrypsin and cigarette smoking in subarachnoid haemorrhage from ruptured aneurysm

An altered equilibrium of protease/protease-inhibitor factors may be involved in the pathogenesis of aneurysm rupture: alpha 1-antitrypsin (alpha 1-AT) represents the most relevant inhibitor of elastase, a proteolytic enzyme enhancing catabolic processes of collagen metabolism. Cigarette smoking has been shown to significantly reduce the inhibitory effect of alpha 1-AT on proteases. In the present study we test the hypothesis whether the activity of alpha 1-AT is altered in patients with subarachnoid haemorrhage (SAH) and if is there any relationship between alpha 1-AT activity and the high risk of aneurysm rupture in smokers. The patients were subdivided in the following groups: (a) patients with unruptured aneurysm (n = 10); (b) patients presenting with SAH admitted within 48 h after the episode (n = 20); (c) patients presenting with SAH admitted > 48 h after the episode (n = 14); (d) controls (n = 10): patients with neither cerebrovascular nor acute disease. Blood samples were obtained immediately at admission. Measurement of alpha 1-AT level was determined by immunoturbidimetric method. In order to obtain qualitative data about the anti-protease activity of alpha 1-AT (expressed as collagenase inhibitory percentage capacity (CIC) at different doses) we consider the 20 cases admitted for SAH within 48 h. The mean serum level of patients with unruptured aneurysms is significantly lower than that of patients with SAH (p < 0.01), while the mean serum level of alpha 1-AT in controls does not significantly differ from other groups. The mean serum level of alpha 1-AT in patients admitted > 48 h after SAH is significantly higher than that of patients admitted within 48 h after the haemorrhage (p < 0.02). Considering the smoking habit of patients, there is no significant difference in alpha 1-AT levels in each subgroup of patients. A multivariate analysis considering alpha 1-AT CIC, showed that alpha 1-AT CIC in patients with ruptured aneurysms is significantly reduced if compared to controls and unruptured aneurysms (F = 50.759; p < 0.001). Moreover, considering alpha 1-AT CIC and smoking habit in each group the covariance analysis showed that while in controls and unruptured aneurysms there is no difference in alpha 1-AT CIC between smokers and non smokers, in cases of SAH, cigarette smoking significantly influences the alpha 1-AT CIC. The present results suggest that the basic mechanism behind the increased risk of SAH in smokers involves a qualitative deficiency of alpha 1-AT.

Alpha1-antitrypsin activity in subarachnoid hemorrhage

An altered equilibrium of protease/protease-inhibitor factors may be involved in the pathogenesis of aneurysm rupture: alpha 1-antitrypsin (alpha 1-AT) represents the most relevant inhibitor of elastase, a proteolytic enzyme enhancing catabolic processes of collagen metabolism. In the present study we test the hypothesis whether the activity of alpha 1-AT is altered in SAH patients; 5 cases with unruptured intracranial aneurysm and 27 patients with diagnosis of aneurysm SAH were included in the study. Blood samples were obtained immediately at admission. As control samples we consider the 5 cases of unruptured aneurysm, 15 cases of unruptured aortic aneurysms and 10 patients with non-vascular CNS diseases. Measurement of alpha 1-AT level was determined by immunoturbidimetric method. Serum levels of alpha 1-AT are significantly lower in patients admitted within 72 hours after SAH, if compared to patients admitted in a delayed phase. The linear relationship between alpha 1-AT and collagenase inhibitory percentage capacity (CIC) was shown to be different in the 4 subgroups considered, and so were the mean % CIC values in the between-groups comparison, except for unruptured aneurysm vs controls. The alpha 1-AT CIC in patients with SAH is shown to be the lowest when compared to controls and unruptured aneurysms (p = 0.0001).

Prognostic value of the amount of post-traumatic subarachnoid haemorrhage in a six month follow up period.

Clinical and radiological patterns from 148 patients with post-traumatic subarachnoid haemorrhage (TSAH) were analysed with specific regard for the amount and distribution of blood in subarachnoid spaces to verify if these variables have any influence on overall outcome. The degree and extent of TSAH were classified according to Fishers criteria: in 93 patients it was grade 1, in 36 grade 2, in 13 grade 3, and in six grade 4. There was a significant correlation between increasing clinical severity at admission and the amount of subarachnoid bleeding and a direct relation between a favourable outcome and a low Fisher grade. The distribution of subarachnoid blood was not significantly related to clinical condition at admission, whereas the pattern had a significant impact on the outcome. The results of the present study confirm that TSAH is a negative prognostic factor. Whereas the degree of TSAH is mainly related to clinical conditions at admission, the presence of subarachnoid blood clots both in basal cisterns and over the cerebral convexity indicates a poor outcome.

Platelet derived growth factor and subarachnoid haemorrhage: a study on cisternal cerebrospinal fluid.

SummaryPlatelet derived growth factor (PDGF) was identified as a powerful mitogenic growth factor which is released from activated platelets and has a marked activity as vasoconstrictor agent. In the present study we have measured cisternal cerebrospinal fluid (CSF) levels of PDGF in 72 patients operated on for intracranial aneurysm in order to verify whether it might be related to the clinical aspects of SAH with special regard to symptomatic vasospasm.CSF samples were obtained at surgery by cisternal puncture of the subarachnoid cistern the nearest to the aneurysm before aneurysm isolation and exclusion. The specimen were frozen in liquid nitrogen and stored at-80 ° C until analysis. PDGF was measured using a commercially available reagent. Values are expressed as pg/ml of CSF.In 18 cases no radiological and clinical signs of SAH were detected and the mean cisternal CSF level of PDGF was 885.0±104.5 pg/ml; 20 patients were operated on between day 1 and 3 from the last SAH episode: mean cisternal CSF level of PDGF was 1917.5±459.4 pg/ml. In 34 patients treated with delayed surgery protocol, mean cisternal CSF level of PDGF was 995.3±73.8 pg/ml. Statistical analysis showed significant differences between groups (P: 0.011). In the subgroup of patients operated on within day 3 after SAH, 6 presented vasospasm and had mean cisternal CSF PDGF level which was significantly higher (P<0.01) than in 14 patients without vasospasm. In the delayed “surgical” patients there was no significant difference in cisternal CSF levels of PDGF considering the occurrence of vasospasm.The results of the present study suggest that (a) after SAH there is a significant release of PDGF early after SAH and (b) higher levels of PDGF found in cisternal CSF of patients operated on within 72 hours after SAH may be predictive of symptomatic vasospasm.

COLLAGEN CROSS-LINKAGE, ELASTOLYTIC AND COLLAGENOLYTIC ACTIVITIES IN CEREBRAL ANEURYSMS : A PRELIMINARY INVESTIGATION

The pathogenesis of aneurysms formation and rupture is not clearly understood and is undoubtedly a multifactorial event. It is generally accepted that the aneurysm arises from an interaction between structural weakness of arterial wall and hemodynamic factors. Previous studies suggested the possible role of collagenolytic and elastolytic activities in aneurysm development, leading to extracellular matrix alteration. The content of collagen 3-hydroxypiridinium cross-links and elastase and collagenase activities were measured in 12 samples of intracranial aneurysms and in control specimens obtained from temporal superficial arteries and from autoptic samples of Willis Circle. Collagen content is significantly lower in aneurysm than in autoptic control samples (p < 0.01). The total amount of cross-links is significantly lower in ruptured aneurysms than in unruptured and autoptic controls (p < 0.01). Collagenase and elastase activities are significantly increased in ruptured cerebral aneurysms versus unruptured aneurysms (p < 0.01). Linear regression shows that an inverse relationship exists between cross-links content and both elastolytic (p = 0.0032) and collagenolytic (p < 0.001) activities in aneurysmal samples. Multiple regression shows that collagenase has a more important statistic impact (p = 0.027) than elastase (p = 0.08). The results of the study supports the hypothesis that an imbalance of protease-antiprotease homeostasis with elevated collagenolytic and elastolytic activities may represent the predisposing condition leading to aneurysms rupture through collagen depauperation and reduced cross-linkage of collagen fibres.

Antioxidant status and α1-antiproteinase activity in subarachnoid hemorrhage patients

The antiproteasic activity of alpha1-antitrypsin (alpha1-AT) is reduced in cases of subarachnoid hemorrhage from ruptured intracranial aneurysm and particularly in patients currently smoking; alpha1-AT is very sensitive to oxidant agents. About 50% of physiological anti-oxidant systemic capacity is represented by Vitamin A, E and C. Plasmatic amounts of alpha1-AT, alpha1-AT Collagenase Inhibitory Capacity (CIC) and levels of vitamin A, vitamin E and vitamin C were analyzed in 39 patients, 26 women and 13 men, operated for intracranial aneurysm; 11 patients with unruptured intracranial aneurysm were considered as controls while 28 patients were included within 12 hours from subarachnoid hemorrhage (SAH). Plasmatic levels of vitamin A and vitamin E were significantly lower (p=0.038 and p=0.0158) in patients suffering SAH than in controls, while no statistically significant differences were found in mean plasmatic vitamin C levels. Level of alpha1-AT was not statistically different in controls and in patients with SAH; however, the activity of alpha1-AT, evaluated as CIC, is significantly reduced in patients with SAH (p=0.019). We have observed that systemic plasmatic levels of vitamins did not significantly differ in relation to smoking habit. Vitamin A and E represent an important defensive system against free radicals reactions. Particularly, vitamin E acts as an antioxidant by scavenging free-radicals. A reduced anti-oxidant status might be related to the higher sensibility of alpha1-AT to oxidative reactions and the activity of alpha1-AT is dependent on the antioxidant capacity of liposoluble vitamins. We can speculate that an acute systemic oxidative stress condition might influence the rupture of intracranial aneurysms.

Deficiency of total collagen content and of deoxypyridinoline in intracranial aneurysm walls

© 1997 Federation of European Biochemical Societies.

Superoxide dismutase activity in cisternal cerebrospinal fluid after aneurysmal subarachnoid haemorrhage.

SummaryIt has been recognised that the level of superoxide dismutase (SOD) significantly increases in CSF as the result of cerebral ischaemic damage. The aim of this study was to correlate the CSF levels of SOD enzymatic activity to the patterns of subarachnoid haemorrhage with regards to ischaemic complications due to vasospasm.A series of 78 patients operated on for intracranial aneurysms was studied; all patients were monitored with serial TCD measurements every second day after SAH. CSF samples were obtained at surgery by cisternal puncture of the subarachnoid cistern nearest to the aneurysm. SOD activity was assayed spectrophotometrically.Mean cisternal CSF level of SOD in 12 control cases (12.99±2.33 U/ml) is significantly higher (p < 0.01) than in 26 patients operated on between day 1 and 3 from last SAH episode (4.44±0.7 U/ml) and in 40 patients treated by delayed surgery (7.64±0.92 U/ml). In 13 patients presenting neurological deterioration related to arterial vasospasm mean cisternal SOD level was 12.23±1.86 U/ml; in 27 cases without vasospasm mean level was 5.43±0.7 U/ml (p < 001).The present results suggest that (a) cisternal CSF levels of SOD significantly decreases after SAH, probably in relation to an impaired synthesis in the brain compartment and that (b) a substantial elevation of SOD levels is evident in patients suffering ischaemic complications vasospasm-related. Biochemical events in the brain compartment could influence the expression and release of anti-oxidant enzymes in CSF after SAH.