Bastianina Zanda

Inflammatory biomarkers in blood of patients with acute brain ischemia

Although many failed surrogate markers are provided in the literature, inflammation may contribute to the outcome of ischemic stroke. In 50 consecutive patients with acute ischemic stroke, in the absence of symptoms and signs of concomitant infection, we evaluated a panel of biomarkers reported to be variably associated with brain ischemia, and correlate their serum level with the brain lesion volume and clinical outcome. Infarct size was calculated on computed tomography (CT) scans by means of the Cavalieris method. Neurological impairment was scored by using the Glasgow Coma Scale, Glasgow Outcome Scale and National Institutes of Health (NIH) scales at stroke onset and 3‐month follow‐up. Some markers showed a direct significant correlation with both initial and final NIH scale and with infarct size, particularly tumor necrosis factor alpha (TNF‐α) (P = 0.002), intercellular adhesion molecule‐1 (P < 0.01) and matrix metalloproteinase‐2/9 (P = 0.001). In contrast to previous reports, interleukin‐6 (IL‐6) serum level showed a significant inverse correlation with both final neurological impairment and infarct size (P < 0.001). This novel finding allows us suggesting that IL‐6, in the context of a complex pro‐inflammatory network occurring during stroke, is associated with neuroprotection rather than neurotoxicity in patients with ischemic brain injury.

Atrial Natriuretic Peptide Gene Polymorphisms and Risk of Ischemic Stroke in Humans

Background and Purpose— A precise definition of genetic factors responsible for common forms of stroke is still lacking. The purpose of the present study was to investigate the contributory role of the genes encoding atrial natriuretic peptide (ANP) and type A natriuretic peptide receptor (NPRA) in humans’ susceptibility to develop ischemic stroke. Methods— Allele and genotype frequencies of ANP and NPRA were characterized in an Italian case-control study with patients affected by vascular disease or risk factors. Subjects were recruited from the island of Sardinia (206 cases, 236 controls). Results— A significant association between the ANP/TC2238 polymorphic site and stroke occurrence was found when a recessive model of inheritance was assumed. The risk conferred by this mutant genotype, when estimated by multivariate logistic regression analysis, was 3.8 (95% confidence interval, 1.4 to 10.9). A significantly increased risk of stroke recurrence was observed among cases carrying the ANP/CC2238 genotype compared with cases carrying the ANP/TT2238 genotype (P =0.04). No direct association of NPRA with stroke occurrence was detected. However, a significant epistatic interaction between the ANP/CC2238 genotype and an allelic variant of NPRA led to a 5.5-fold increased risk of stroke (95% confidence interval, 1.5 to 19.4). Conclusions— Our findings support a direct contributory role of ANP to stroke in humans. A significant interaction between ANP and NPRA on stroke occurrence was found.

The PlA1/A2 polymorphism of glycoprotein IIIa and cerebrovascular events in hypertension: Increased risk of ischemic stroke in high-risk patients

Objective The platelet GPIIIa plays a pivotal role in platelet aggregation. Previous studies showed an association between the GPIIIa PlA1/A2 polymorphism and coronary thrombosis, while there is only contrasting evidence about its role in stroke. We explored the possibility that this polymorphism represents a risk factor for stroke in hypertensive patients. Methods We studied two populations. In loco, we genotyped 140 hypertensive control individuals and 28 hypertensive patients with ischemic stroke. Furthermore, we performed an analysis of previously published data of 451 Sardinian hypertensive patients, already characterized and genotyped. Results Association analysis revealed that the PlA2 distribution was similar between hypertensive patients with and without stroke, but when considering a more homogeneous population of high-risk hypertensive patients, defined according to ESH/ESC 2003 guidelines, we observed that the frequency of the PlA2 allele was higher among stroke versus nonstroke patients (stroke, 46.4%; nonstroke, 22.6%; P = 0.01). The multiple regression analysis taking into account this polymorphism among other factors known to contribute to ischemic stroke confirmed the PlA2 allele as an additive risk factor for stroke (B = 0.986, Wald = 4.943, P < 0.03), increasing the risk of stroke by 2.9 (95% confidence interval = 1.23–6.85, P < 0.02). Similar results were obtained in the Sardinian population: in hypertensive patients with three or more risk factors, PlA2 increases the risk (odds ratio = 2.8, 95% confidence interval = 1.3–6.0, P < 0.001) and is an additive risk factor for stroke (B = 1.073, Wald = 6.920, P < 0.01). Conclusions Our data suggest that the PlA2 polymorphism is a genetic determinant of ischemic stroke in a selected high-risk hypertensive population.

Gene polymorphisms of the renin-angiotensin-aldosterone system and the risk of ischemic stroke: a role of the A1166C/AT1 gene variant.

Objective The role of the renin–angiotensin–aldosterone system (RAAS) genes on predisposition to develop stroke, a multifactorial and polygenic cardiovascular trait, is still under investigation. In the present study we characterized the contributory role of RAAS genes in the susceptibility to develop ischemic stroke in humans. Methods Allele and genotype frequencies of RAAS genes were characterized in a population of 215 cases (including only atherothrombotic and lacunar forms) and 236 controls selected in Sardinia, a large Mediterranean island with a well-known segregated population. Statistical analysis was performed in the whole population and, based on a significant interaction between angiotensin II receptor (AT1) genotype and hypertension, was also repeated in the hypertensive subgroup. Results A significant association of the C1166/AT1 gene allelic variant with stroke was found when assuming a dominant model of transmission [unadjusted odds ratio (OR) = 1.5, 95% confidence interval (CI) 1.1–2.2, P = 0.024]. The strength of the association became more evident in the subgroup of hypertensive individuals (135 cases and 110 controls). In fact, in this cohort the independent OR for the AT1 gene was 2.1, 95% CI 1.2–3.7, P = 0.006 in the dominant model and 2.0, 95% CI 1.3–3.2, P = 0.002 in the additive model. No other RAAS gene was identified as a contributor to stroke. Conclusions Our findings support a predisposing role of an AT1 gene variant in the development of ischemic stroke. In particular, the AT1 gene variant exerted a major impact on ischemic stroke occurrence in the presence of hypertension.

Chitotriosidase in Patients with Acute Ischemic Stroke

Background: Following an acute brain ischemia, local endothelia allow monocyte chemoattraction into the lesion site which contributes to brain damage through a group of neurotoxic factors. A relationship exists between the extent of brain damage and the plasma level of monocyte products, including chitotriosidase, though usually strictly related to preexisting infectious-inflammatory diseases. Purpose: Since chitotriosidase activity is also elevated in pathogen-free conditions, we tested whether chitotriosidase upregulation might be specifically related to stroke and unrelated to clinically relevant infectious diseases. Methods: We studied the plasma level of chitotriosidase activity, TNF-α and IL-6 in 44 consecutive patients with acute brain ischemia without concomitant symptoms or signs of inflammatory-infectious diseases. Results were compared with stroke severity and outcome as detected by brain CT and NIH scale. Blood samples were collected, on average, 11 h after stroke onset. Results: Chitotriosidase activity positively correlates with stroke severity, as measured by NIH scale (r = 0.69, p<0.01), to the extent of brain damage as documented by CT (r = 0.75, p ≤ 0.001) and the TNF-α level (r = 0.76, p<0.001); it also inversely correlates with the IL-6 level (r = –0.43, p ≤ 0.05). Conclusion: Our results indicate that chitotriosidase is a specific marker of macrophage activation occurring in stroke which directly correlates with stroke severity independently of preexisting inflammatory or infectious conditions.

Polymorphisms in prothrombotic genes and their impact on ischemic stroke in a Sardinian population

Genetic factors are involved in the individual predisposition to develop ischemic stroke (IS). In the present study we tested the role of the Factor VII G10976A and -C122T polymorphisms on the susceptibility to develop IS in a genetically homogenous and clinically well ascertained case-control study including 294 cases (median age 75 years; 176 males/118 females) and 286 controls (median age 73 years; 163 males/123 females) in Sardinia, Italy. In addition, we carried out an exploratory analysis with respect to other frequently studied polymorphisms of haemostatic factor genes:Factor II G20210A, Factor V G1691A,,Fibrinogen alpha-chain Thr312Ala, Fibrinogen beta-chain -C148T, Factor XIII G185T, GPIIb/IIIa T1565C. Among all the genes tested, FVII -C122T showed a significant, independent contribution to IS predisposition both in crude and adjusted analyses (crude OR 1.52, 95% CI 1.09-2.10, P=0.013; adjusted OR 1.48, 95% CI 1.04-2.09, P=0.028, respectively). Haplotype analyses revealed a conserved population structure with high linkage disequilibrium between both FVII mutations tested. Blood levels of FVII had an inverse relationship with the polymorphism involved. Apart from genetic influence, there was a significant role for hypertension (OR=1.7, 95% CI 1.19-2.43, P=0.003), hypercholesterolemia (OR=2.21, 95% CI 1.38-3.54, P=0.001) and atrial fibrillation (OR=1.66, 95% CI 1.06-2.58, P=0.026) on IS occurrence. In summary, we describe evidence for a possible direct association of FVII gene molecular variants with the occurrence of IS in a genetically homogenous human sample.

Phosphodiesterase 4D and 5-lipoxygenase activating protein genes and risk of ischemic stroke in Sardinians

Genetic factors contribute to the risk of ischemic stroke (IS). The phosphodiesterase-4D (PDE4D) and the 5-lipoxygenase activating protein (ALOX5AP) genes were identified as contributors to stroke in an Icelandic population. In an attempt to better define the contributory role of PDE4D and ALOX5AP genes to the risk of IS in humans, we carried out the present association study in a well-characterized, earlier published, genetically homogenous population from the island of Sardinia, Italy. In this cohort, including 294 cases and 235 controls, age, hypertension, hypercholesterolemia, and atrial fibrillation represent risk factors for IS. The PDE4D gene was evaluated by four single nucleotide polymorphisms (SNP32, SNP45, SNP83, SNP87) and by the microsatellite AC008818-1; the ALOX5AP gene was characterized by three SNPs (SG13S32, SG13S89, ALO2A). The results of our study provide no evidence of association between any single PDE4D and ALOX5AP gene variant with the risk of IS in the Sardinian cohort. Haplotype analysis, including that constructed with allele 0 of microsatellite AC008818-1 and SNP45 of the PDE4D gene, was also negative. In conclusion, we found no evidence of association between PDE4D and ALOX5AP genes and the risk of IS in a genetically homogenous population from Sardinia.

A protective role of a cholesteryl ester transfer protein gene variant towards ischaemic stroke in Sardinians

Objectives.  Cholesteryl ester transfer protein (CETP) plays a key role in the metabolism of high‐density lipoprotein (HDL), a strong, inverse, independent risk factor for cardiovascular disease.