Plasma factor VII-activating protease antigen levels and activity are increased in ischemic stroke

BACKGROUND

Factor VII-activating protease (FSAP) is a recently discovered plasma protease with a role in the regulation of hemostasis and vascular remodeling processes. Higher levels and activity of FSAP have been reported in patients with deep vein thrombosis, but there are no data on plasma FSAP in ischemic stroke (IS).

OBJECTIVE

To investigate whether FSAP antigen levels and activity are associated with IS and/or etiologic subtypes of IS.

PATIENTS AND METHODS

To assess the potential association between FSAP and IS, plasma FSAP antigen levels and activity were measured in 600 consecutive IS patients and 600 population-based controls from the case-control study the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS). Blood sampling was performed in the acute phase and 3 months after the index stroke. FSAP was also investigated at the genetic level by genotyping of 33 single-nucleotide polymorphisms.

RESULTS

Increased FSAP antigen level and activity, at both time-points, were independently associated with IS. Subtype analysis revealed similar associations for both FSAP measures, at both time-points, in all main IS subtypes. FSAP genotypes showed association with both FSAP plasma measurements, but not with IS.

CONCLUSIONS

Increased plasma FSAP antigen levels and activity were associated with IS and all main etiologic subtypes, suggesting a possible role for FSAP in the pathophysiology of IS, irrespective of the underlying etiology.

Changes in plasma matrix metalloproteinase-9 levels in patients with acute ischemic stroke

Matrix metalloproteinases (MMP) have been thought to be involved in stroke pathogenesis. MMP-9 contributes to tissue destruction. Our aim was to analyze the MMP-9 levels in blood within 24 hours of acute ischemic stroke onset to observe the role of MMP-9 in the pathogenesis of atherothrombotic stroke. In this study we investigated prospectively MMP-9 levels in serum from 106 patients (42 men and 64 women, mean age 71.52 +/- 6.32 years) with acute ischemic stroke in the middle cerebral artery area in the first 24 hours from the onset (mean duration 7.8 +/- 4.5 hours) as compared to 112 controls (48 men and 64 women, mean age 70.36 +/- 6.8 years). Serum samples were collected under sterile conditions and stored in aliquots at -70 degrees C until assay. Serum MMP-9 levels were determined by enzyme-linked immunosorbent assay (ELISA) in blood samples obtained on admission. Statistical analysis was performed by Mann-Whitney and Log-Likeliwood Ratio tests. All values reported are expressed as mean (x) +/- SD. Mean serum MMP-9 concentrations were higher in group with ischemic stroke 172 +/- 32.4 ng/mL, range 139.6-204.4 ng/mL vs. controls 57 +/- 9.6 ng/mL, range 47.4-66.6 ng/mL (95% CI, 3.17 to 14.18; p < 0.014). In conclusion, MMP-9 activity is associated with early acute ischemic stroke. The high levels of MMP-9 in acute ischemic stroke document the involvement of this enzyme in the regulation of inflammation in stroke.

Age-related changes in AMP-activated protein kinase after stroke

Adenosine monophosphate-activated protein kinase (AMPK) is an evolutionary conserved energy sensor sensitive to changes in cellular AMP/ATP ratio which is activated by phosphorylation (pAMPK). pAMPK levels decrease in peripheral tissues with age, but whether this also occurs in the aged brain, and how this contributes to the ability of the aged brain to cope with ischemic stress is unknown. This study investigated the activation of AMPK and the response to AMPK inhibition after induced stroke in both young and aged male mice. Baseline levels of phosphorylated AMPK were higher in aged brains compared to young mice. Stroke-induced a robust activation of AMPK in young mice, yet this response was muted in the aged brain. Young mice had larger infarct volumes compared with aged animals; however, more severe behavioral deficits and higher mortality were seen in aged mice after stroke. Inhibition of AMPK with Compound C decreased infarct size in young animals, but had no effect in aged mice. Compound C administration led to a reduction in brain ATP levels and induced hypothermia, which led to enhanced neuroprotection in young but not aged mice. This work demonstrates that aging increases baseline brain pAMPK levels; aged mice have a muted stroke-induced pAMPK response; and that AMPK inhibition and hypothermia are less efficacious neuroprotective agents in the aged brain. This has important translational relevance for the development of neuroprotective agents in preclinical models and our understanding of the enhanced metabolic stress experienced by the aged brain.

Variants within the nitric oxide synthase 1 gene are associated with stroke susceptibility

OBJECTIVE

Animal studies have allowed important insights into the role of the nitric oxide synthase (NOS) enzymes in atherosclerosis and hypertension, as well as in stroke. In this study we tested the hypothesis that the NOS1 and NOS3 genes, respectively encoding neuronal NOS (nNOS) and endothelial NOS (eNOS), influence stroke susceptibility and outcome after a stroke event.

METHODS

We conducted a case-control association study in 551 ischemic stroke patients and 530 controls to assess the role of NOS1 and NOS3 variants in stroke susceptibility. The same genes were tested for association with stroke outcome in a subset of 431 patients.

RESULTS

Four NOS1 single nucleotide polymorphisms (SNPs) (rs2293050, rs2139733, rs7308402 and rs1483757) and four haplotypes were significantly associated with stroke susceptibility after adjusting for demographic, clinical and life-style risk factors, and correcting for multiple testing using the false discovery rate (FDR) method (SNPs: 0.004<(uncorrected)P<0.007 and 0.036<FDR q<0.048; haplotypes: 0.001<(uncorrected)P<0.010 and 0.018<FDR q<0.032). NOS1 variants were not associated with stroke outcome. We did not find any evidence for a role of the NOS3 gene in stroke susceptibility or outcome.

CONCLUSION

Our results highlight NOS1 as a susceptibility factor for stroke, but do not corroborate previous NOS3 association findings with stroke risk. nNOS is known to play a major role in atherosclerosis development and in blood flow regulation, and it is plausible that its influence in stroke may be mediated through these two main clinical risk factors.

High blood glutamate oxaloacetate transaminase levels are associated with good functional outcome in acute ischemic stroke

The capacity of the blood enzyme glutamate oxaloacetate transaminase (GOT) to remove glutamate from the brain by means of blood glutamate degradation has been shown in experimental models to be an efficient and novel neuroprotective tool against ischemic stroke; however, the beneficial effects of this enzyme should be tested in patients with stroke to validate these results. This study aims to investigate the association of GOT levels in blood with clinical outcome in patients with acute ischemic stroke. In two clinical independent studies, we found that patients with poor outcome show higher glutamate and lower GOT levels in blood at the time of admission. Lower GOT levels and higher glutamate levels were independently associated with poorer functional outcome at 3 months and higher infarct volume. These findings show a clear association between high blood glutamate levels and worse outcome and vice versa for GOT, presumably explained by the capacity of this enzyme to metabolize blood glutamate.

Traditional Chinese medicine, Xue-Fu-Zhu-Yu decoction, potentiates tissue plasminogen activator against thromboembolic stroke in rats

AIM OF THIS STUDY

The Xue-Fu-Zhu-Yu decoction (XFZYD) is a well-known traditional Chinese medicine for treating cardiovascular diseases. The therapeutic effects of this XFZYD have been well documented especially in treating of atherosclerosis and hyperlipidemia. Since this decoction can induce endothelial progenitor cell angiogenesis, it can provide experimental evidence for the treatment of ischemic diseases. Patients who are admitted to the hospital with acute ischemic stroke are initially considered candidates for the recombinant tissue plasminogen activator (rt-PA). However, rt-PA therapy is still lesser than ideal due to its major side effect of hemorrhaging. Therefore, medical research has been devoted to finding an alternative and/or complementary therapy for ischemic stroke. In the present study, we evaluated the protective effect of the combination of XFZYD with or without rt-PA in a rat model of thromboembolic stroke.

MATERIALS AND METHODS

A cerebral thromboembolic stroke animal model and immunoblotting analysis were used to assess the effects of XFZYD and rt-PA.

RESULTS

Treatment with rt-PA (8 mg/kg) or XFZYD (1.5 and 3.0 g/kg/day) alone showed slight reductions in the infarct volume compared to solvent-treated rats. However, XFZYD (1.5 and 3.0 g/kg/day) obviously potentiated rt-PA-mediated reduction in the infarct volume in cerebral ischemic regions. In addition, treatment with rt-PA significantly reduced both tumor necrosis factor (TNF)-α and inducible nitric oxide synthase (iNOS) but not hypoxia-inducible factor (HIF)-1 α or active caspase-3 expressions in ischemic regions, whereas treatment with XFZYD (3.0 g/kg/day) significantly reduced all of these protein expressions in ischemic regions. Moreover, treatment with XFZYD (1.5 and 3.0 g/kg/day) obviously potentiated rt-PA-mediated reductions in TNF-α, iNOS, HIF-1 α, and active caspase-3 expressions.

CONCLUSIONS

Results of this study suggest that XFZYD potentiated rt-PA-mediated neuroprotection against thromboembolic stroke in rats. This neuroprotection is probably mediated by the inhibition of HIF-1 α and TNF-α, followed by the inhibition of inflammatory responses (i.e., iNOS) and apoptosis (active caspase-3). These results provide a better understanding of the scientific validation of the therapeutic value of the combination of XFZYD with rt-PA in ischemic stroke.

Sex differences in the response to poly(ADP-ribose) polymerase-1 deletion and caspase inhibition after stroke

BACKGROUND AND PURPOSE

Emerging data suggest that the molecular cell death pathways triggered by ischemic insults differ in the male and female brain. Cell death in males is initiated by poly(ADP-ribose) polymerase-1 (PARP-1) activation; however, manipulation of this pathway paradoxically increases ischemic damage in females. In contrast, females are exquisitely sensitive to caspase-mediated cell death. The effect of caspase inhibition in PARP-1 knockout mice was evaluated to determine if the detrimental effects of PARP deletion in females were secondary to increased caspase activation.

METHODS

Focal stroke was induced by transient or permanent middle cerebral artery occlusion (MCAO) in wild-type (WT) and PARP-1(-/-) mice of both sexes. The pan-caspase inhibitor, quinoline-Val-Asp(Ome)-CH2-O-phenoxy (Q-VD-OPh), was administered 90 minutes after middle cerebral artery occlusion. Infarct size and neurological sores were assessed. Separate cohorts were used for protein analysis for PAR, Apoptosis inducing factor (AIF), caspase-9, and caspase-3.

RESULTS

WT mice of both sexes had increased nuclear AIF after stroke compared to PARP-1(-/-) mice. PARP-1(-/-) females had higher mitochondrial cytochrome C and activated caspase-9 and -3 levels than WT female mice. PARP-1(-/-) females also had an increase in stroke-induced cytosolic cytochrome C release compared with WT females, which was not seen in males. Q-VD-OPh decreased caspase-9 in both males and females but only led to reduction of infarct in females. PARP-1(-/-) males had smaller infarcts, whereas PARP-1(-/-) females had larger strokes compared with WT. Q-VD-OPh significantly decreased infarct in both WT and PARP-1(-/-) females in both transient and permanent MCAO models, but had no effect in males.

CONCLUSIONS

Deletion of PARP-1 reduces infarct in males but exacerbates injury in females. PARP-1(-/-) females have enhanced caspase activation. The detrimental effects of PARP loss in females can be reversed with caspase inhibition.

Soluble epoxide hydrolase: a promising therapeutic target for cardiovascular diseases

Epoxyeicosatrienoic acids (EETs) are cytochrome P450 (CYP450) products of arachidonic acid and EETs are endogenous lipid mediators synthesized by the vascular endothelium which perform important biological functions, including vasodilation, anti-inflammation, antimigratory, and cellular signaling regulations. However, EETs are rapidly degraded by soluble epoxide hydrolase (sEH) to the corresponding diols: dihydroxyeicosatrienoic acids (DHETs), which have little active in causing vasorelaxation. A number of studies have supported that the inhibition of sEH (sEHIs) had cardiovascular protective effects in hypertension, cardiac hypertrophy, atherosclerosis, ischemia-reperfusion injury, and ischemic stroke. Moreover, sEHIs could slow the progression of inflammation, protect end-organ damage and prevent ischemic events, also, attenuate endothelial dysfunction, suggesting that the pharmacological blockade of sEH might provide a broad and novel avenue for the treatment of many cardiovascular diseases.

[Efficacy of replacement enzyme therapy on central nervous system manifestations in Fabry's disease]

INTRODUCTION

Fabry's disease (FD) an X-linked inherited lysosomal sphingolipidosis leads to a multisystemic disease. The efficacy of replacement enzyme therapy on the central nervous system manifestations has not been evaluated.

OBSERVATION

A 38-year-old patient suffered from a Fabry's disease diagnosed at the age of 10. Since the age of 26, he suffered from repeated ischemic strokes. Since the age of 34, he was treated by enzyme replacement therapy (agalsidase beta, 1 mg/kg/14 days). He had a cerebral MRI evaluation 1 year and 4 years after the initiation of the enzyme therapy. No new clinical event occurred during the follow-up and the imaging did not evidence new lesion.

DISCUSSION

We report the cerebral MRI follow-up under enzyme replacement therapy in a patient with Fabry's disease with central nervous system involvement. No new lesion appeared.

CONCLUSION

Enzyme replacement therapy seems beneficial in Fabry's disease with central nervous system involvement.

Clinico-pathological correlations in fatal ischemic stroke. An immunohistochemical study of human brain penumbra

Ischemic stroke is one of the most frequent pathologies with high invalidating potential and a leading cause of death. The brain tissue adjacent to the central necrotic core, defined as penumbra, was extensively characterized mostly by imaging techniques and in animal models. Our goal was to identify a large panel of molecules in this particular area on human brains harvested at autopsy. Twenty-one patients with ischemic stroke and seven control cases were taken into study. We used immunohistochemistry to characterize necrotic lesions. Metalloproteinases, mostly MMP-9, seem to be involved in brain ischemia, but as a protective and not as a deleterious factor. Apoptotic molecules are not increasingly expressed in stroke compared to control cases. Mast cell enzymes chymase and tryptase are described for the first time in neurons and glia, even with unclear significance. Microglia appears active in stroke and stimulating methods directed to it could be useful. Nitric oxide synthases and cyclooxygenase-2 were also involved in stroke cases but not in control ones. Other factors as VEGF and its receptors, PDGF, b-FGF or TNF-alpha showed no significant expression related to ischemic brain injury. Animal study of penumbra and human tissue findings are distinct and research should be focused on the latter approach in order to find valuable and safe therapeutic methods.

[Role of semicarbazide-sensitive amine oxidase in disturbances of endogenic detoxication in ischemic stroke patients]

Oxidative stress is a pathogenetic factor of ischemic stroke. Enhancement in the activity of one of xenobiotic transformation enzymes and biogenic amines (serum semicarbazide-sensitive amine oxidase (SSAO)) leads to the higher production of secondary toxins stimulating oxidative stress. We studied 38 patients (mean age 69,5 +/- 7,2 years) in the early restoration period of ischemic stroke. A control group included 17 age- and sex-matched healthy people. Severity of neurological and functional deficits was assessed with the NIHSS and the Barthel index, respectively. A number of biochemical parameters: serum SSAO activity, concentration of middle-sized molecules (MSM) and malonic dialdehyde (MDA) were measured. The higher concentration of MSM (0,80 +/- 0,22 and 0,5 +/- 0,1 g/l) and MDA (4,5 +/- 1,25 and 3,66 +/- 0,15 mmol/ml), respectively, was found in patients compared to the controls (p < 0,001). The correlative increase in MSM and MDA suggest the formation of chronic oxidative stress in the 4-5 months of disease. The changes in SSAO activity in patients with ischemic stroke that differed from controls were seen in 84% of cases while the increase in SSAO activity was found in 31% of patients. The pathogenetic link between the increase in SSAO activity and severity of neurological deficit was shown. This increase might be one of the pathogenetic links in the disturbance of neuroplasticity.

Plasma glutathione peroxidase in pediatric stroke families

BACKGROUND/OBJECTIVES

Promoter polymorphisms in the plasma glutathione peroxidase gene (GPX3), which encodes a major antioxidant enzyme implicated in post-translational modification of fibrinogen, have been implicated as risk factors for arterial ischemic stroke (AIS) and cerebral sinovenous thrombosis (CSVT) in young adults. However, the contribution of these polymorphisms could not be confirmed by other studies.

PATIENTS/METHODS

The aim of the present study was to investigate the association of three haplotype-tagging single-nucleotide polymorphisms (htSNPs) in GPX3 in a large family-based study sample comprising 268 nuclear families with different pediatric AIS subtypes, i.e. arteriopathy stroke (AS) and thromboembolic stroke (TS). In addition, an independent study sample comprising 154 nuclear families of pediatric CSVT was investigated. Single-point and haplotype association was assessed with the transmission disequilibrium test implemented in haploview.

RESULTS

Single-point analysis revealed that the G allele of htSNP rs8177412 was significantly overtransmitted to affected AS children (T/U = 25 : 11, χ(2) = 5.54, P = 0.019), but not to affected TS children (T/U = 49 : 40, χ(2) = 0.91, P = 0.34). The corresponding GG haplotype (H2: frequency 0.18) was also significantly overtransmitted to AS children (T/U = 23 : 11, χ(2) = 4.28, P= 0.03), but not to TS children or in children with CSVT. These results remained significant following 10,000 bootstrap permutations. Our findings indicate that genetic variants of GPX3 are risk factors for AS, but not for thromboembolic AIS or CSVT, in children.

CONCLUSIONS

Our results further highlight the need to analyze the contribution of genetic variants to pediatric AS, TS or CSVT separately, as these subcategories probably result from different combinations of risk-conferring and protective genetic variations.

C677T and A1298C methylenetetrahydropholate reductase (MTHFR) polymorphisms as factors involved in ischemic stroke

BACKGROUND

Ischemic stroke is a major health problem. Data regarding the possible association between ischemic stroke and the polymorphism of methylenetetrahydropholate reductase (MTHFR) C677T and A1298C are still conflictual.

AIM

The study tried to assess the association of the two MTHFR polymorphisms with ischemic stroke in a series of patients from a unique hospital center.

MATERIALS AND METHODS

The study comprised a total of 127 patients (67 with non-cardioembolic ischemic stroke diagnosed by computed tomography or magnetic resonance imaging) and 60 control cases. The method we used was reverse hybridization performed on peripheral blood for C677T and A1298C polymorphisms. In all patients a careful clinical examination, laboratory analyses of cholesterol, glucose amount and triglycerides, as well as their medical history were available.

RESULTS

The mean age of stroke patients was 68.73 years, and 55.2% were males. Gene analysis for C677T disclosed the presence of TT genotype in more control subjects than in stroke series (15% and 7.46% respectively). Also, the overall T allele (CT+TT cases) was present in 71.6% of control cases, as compared with 44.7% stroke patients. 1298C allele was almost equally distributed among the two series. No statistically significant correlations of the two genotypes with infarct localization and dimensions ant with other potential risk factors (hypertension, lipids, diabetes mellitus) were observed.

CONCLUSIONS

The two MTHFR polymorphisms, C677T and A1298C, seemed not related to the onset of ischemic stroke in our study. However, they could be rather involved in hemorrhagic stroke, as seen in our control patients. Further evaluation on larger series is mandatory since homocysteine activity (related to MTHFR activity) could be easily influenced by folate or cobalamin derivatives.

Pregabalin suppresses calcium-mediated proteolysis and improves stroke outcome

Pregabalin, a Ca(2+) channel α(2)δ-subunit antagonist with analgesic and antiepileptic activity, reduced neuronal loss and improved functional outcome in a mouse model of focal ischemic stroke. Pregabalin administration (5-10mg/kg, i.p.) 30-90 min after transient middle cerebral artery occlusion/reperfusion reduced infarct volume, neuronal death in the ischemic penumbra and neurological deficits at 24h post-stroke. Pregabalin significantly decreased the amount of Ca(2+)/calpain-mediated α-spectrin proteolysis in the cerebral cortex measured at 6h post-stroke. Together with the extensive clinical experience with pregabalin for other neurological indications, our findings suggest the potential for a therapeutic benefit of pregabalin in stroke patients.

Post-stroke inhibition of induced NADPH oxidase type 4 prevents oxidative stress and neurodegeneration

Ischemic stroke is the second leading cause of death worldwide. Only one moderately effective therapy exists, albeit with contraindications that exclude 90% of the patients. This medical need contrasts with a high failure rate of more than 1,000 pre-clinical drug candidates for stroke therapies. Thus, there is a need for translatable mechanisms of neuroprotection and more rigid thresholds of relevance in pre-clinical stroke models. One such candidate mechanism is oxidative stress. However, antioxidant approaches have failed in clinical trials, and the significant sources of oxidative stress in stroke are unknown. We here identify NADPH oxidase type 4 (NOX4) as a major source of oxidative stress and an effective therapeutic target in acute stroke. Upon ischemia, NOX4 was induced in human and mouse brain. Mice deficient in NOX4 (Nox4(-/-)) of either sex, but not those deficient for NOX1 or NOX2, were largely protected from oxidative stress, blood-brain-barrier leakage, and neuronal apoptosis, after both transient and permanent cerebral ischemia. This effect was independent of age, as elderly mice were equally protected. Restoration of oxidative stress reversed the stroke-protective phenotype in Nox4(-/-) mice. Application of the only validated low-molecular-weight pharmacological NADPH oxidase inhibitor, VAS2870, several hours after ischemia was as protective as deleting NOX4. The extent of neuroprotection was exceptional, resulting in significantly improved long-term neurological functions and reduced mortality. NOX4 therefore represents a major source of oxidative stress and novel class of drug target for stroke therapy.

Delayed treatment with systemic (S)-roscovitine provides neuroprotection and inhibits in vivo CDK5 activity increase in animal stroke models

Background

Although quite challenging, neuroprotective therapies in ischemic stroke remain an interesting strategy to counter mechanisms of ischemic injury and reduce brain tissue damage. Among potential neuroprotective drug, cyclin-dependent kinases (CDK) inhibitors represent interesting therapeutic candidates. Increasing evidence indisputably links cell cycle CDKs and CDK5 to the pathogenesis of stroke. Although recent studies have demonstrated promising neuroprotective efficacies of pharmacological CDK inhibitors in related animal models, none of them were however clinically relevant to human treatment.

Methodology/Principal Findings

In the present study, we report that systemic delivery of (S)-roscovitine, a well known inhibitor of mitotic CDKs and CDK5, was neuroprotective in a dose-dependent manner in two models of focal ischemia, as recommended by STAIR guidelines. We show that (S)-roscovitine was able to cross the blood brain barrier. (S)-roscovitine significant in vivo positive effect remained when the compound was systemically administered 2 hrs after the insult. Moreover, we validate one of (S)-roscovitine in vivo target after ischemia. Cerebral increase of CDK5/p25 activity was observed 3 hrs after the insult and prevented by systemic (S)-roscovitine administration. Our results show therefore that roscovitine protects in vivo neurons possibly through CDK5 dependent mechanisms.

Conclusions/Significance

Altogether, our data bring new evidences for the further development of pharmacological CDK inhibitors in stroke therapy.

Kinetics differ between copper-zinc and manganese superoxide dismutase activity with acute ischemic stroke

This study aimed to clarify the kinetics of copper-zinc (CuZn) and manganese (Mn) superoxide dismutase (SOD) activity in acute ischemic stroke victims. Using the nitrite method, we investigated sequential changes in CuZn and Mn SOD activity in the cerebrospinal fluid (CSF) of 8 patients with acute ischemic stroke. SOD activity in each patient was measured at 36 hours and 3, 7, 14, and 28 days after stroke. CuZn SOD activity in CSF peaked 3 days after stroke, with values gradually decreasing after 7 days. In contrast, Mn SOD activity remained significantly lower in the stroke group than in controls throughout the study. These findings may reflect differences between the 2 isoenzymes in terms of the distribution, role, and method of synthesis in brain tissue.

A novel loss-of-function DDAH1 promoter polymorphism is associated with increased susceptibility to thrombosis stroke and coronary heart disease

RATIONALE

Asymmetrical dimethylarginine (ADMA), an endogenous arginine analogue, inhibits nitric oxide synthases and plays an important role in endothelial dysfunction.

OBJECTIVE

In the present study, we tested whether a novel genetic variant in dimethylarginine dimethylaminohydrolase 1 (DDAH1), an important ADMA hydrolyzing gene, was associated with stroke and coronary heart disease (CHD) susceptibility in the Chinese Han population.

METHODS AND RESULTS

By resequencing, we identified a novel 4-nucleotide deletion/insertion variant in the DDAH1 promoter. The insertion allele disrupted binding of metal-regulatory transcription factor 1, which resulted in significant reduction of in vitro DDAH1 transcriptional activity and in vivo DDAH1 mRNA level, and in turn, increased plasma ADMA level and the ratio of ADMA to L-arginine. We initially genotyped the polymorphism in 1388 stroke patients and 1027 controls as well as 576 CHD patients and 557 controls and then replicated our study in additional independent case-control cohorts comprising 961 stroke patients and 822 controls and 482 CHD patients and 1072 controls. We identified that the -396 4N ins allele was significantly associated with increased risk of thrombosis stroke and CHD after adjusting for environmental factors in both samples for both diseases (thrombosis stroke discovery set: odds ratio [OR]=1.35, P=0.032; replication set: OR=1.51, P=0.006; CHD discovery set: OR=1.45, P=0.035; replication set: OR=1.47, P=0.003).

CONCLUSIONS

Our results suggest that the DDAH1 loss-of-function polymorphism is associated with both increased risk of thrombosis stroke and CHD.

Plasma myeloperoxidase levels in patients with acute ischemic stroke

Myeloperoxidase (MPO) is a glycoprotein released by activated polymorphonuclear neutrophils, which takes part in the defence of the organism through production of hypochlorous acid (HOCl), a potent oxidant. MPO has a role in pathogenesis of atherosclerosis. The aim of the study was to evaluate the time course of MPO plasma levels in the early stage of ischemic stroke. The study included 78 patients with acute ischemic stroke, 46 females and 32 males, mean age 74.3 +/- 6.8 years. Blood samples for MPO measurement were taken within 24 hours after the onset of ischemic stroke. Seventy-two patients served as matched controls 43 females and 29 males, mean age 71.3 +/- 6.4 years. MPO was measured in plasma using the Abbott Architect platform (Abbott Diagnostics Inc., Abbott Parck IL). Comparisons between patients and controls and patients group were expressed as relative risk with its 95% confidence interval (RR [95% CI]), where a lower limit > 1.0 was considered significant. All p values were determined by Fischer's exact test. A value of p < 0.05 was considered statistically significant. Mean plasma MPO level was in patients with acute ischemic stroke 583 +/- 48 pmol/L. Seventy-one patients out of seventy-eight patients with ischemic stroke presented mean plasma MPO levels greater than the upper of normal (425 +/- 36 pmol/L, p < 0.0001, (RR 8.188, [95% CI 4.038 to 16.600]). Twelve controls presented mean plasma MPO level greater than the upper of normal. In conclusion, plasma MPO levels were statistically significantly higher in patients after ischemic stroke as compared to controls. MPO has been associated with acute ischemic stroke but its direct role in its pathogenesis has not been established. MPO could be proposed as a potential prognostic marker of such lesions rather than a marker of diagnosis. MPO is a new biomarker and a possible future therapeutic target.

Multiple roles of HDAC inhibition in neurodegenerative conditions

Histone deacetylases (HDACs) play a key role in homeostasis of protein acetylation in histones and other proteins and in regulating fundamental cellular activities such as transcription. A wide range of brain disorders are associated with imbalances in protein acetylation levels and transcriptional dysfunctions. Treatment with various HDAC inhibitors can correct these deficiencies and has emerged as a promising new strategy for therapeutic intervention in neurodegenerative disease. Here, we review and discuss intriguing recent developments in the use of HDAC inhibitors to combat neurodegenerative conditions in cellular and disease models. HDAC inhibitors have neuroprotective, neurotrophic and anti-inflammatory properties; improvements in neurological performance, learning/memory and other disease phenotypes are frequently seen in these models. We discuss the targets and mechanisms underlying these effects of HDAC inhibition and comment on the potential for some HDAC inhibitors to prove clinically effective in the treatment of neurodegenerative disorders.

[Lipoprotein-associated phospholipase A(2) and stroke]

INTRODUCTION

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an enzyme member of A2 phosholipases superfamily. The 80% circulates bound to LDL-cholesterol and levels of both parameters are positively correlated. The main function of this enzyme is to hydrolyze oxidized phospholipids contained in LDL-cholesterol forming pro-inflammatory products in atheroma plaque. Several studies related raised Lp-PLA2 and vascular risk.

AIM

To review available data relating Lp-PLA2 and stroke.

DEVELOPMENT

Different cohorts and cases and controls studies showed an association between higher levels of Lp-PLA2 and the risk of suffering: first cardiovascular event (coronary heart disease, ischemic stroke) or its recurrence; progression of coronary damage evaluated using cardiac computed tomography; or death of cardiovascular cause. Published risk measurements are less than 2 and it has been demonstrated that raised levels of enzyme are risk factor independent of classic cardiovascular risk factors and non-HDL cholesterol and C-reactive protein levels. The clinical data and the knowledge of the role of Lp-PLA2 in plaque destabilization justified the development of inhibitor drugs.

CONCLUSIONS

According to current evidence, patients in the higher range of Lp-PLA2 may be considerate at higher risk of suffering a vascular event. The application to stroke needs a better definition of the pathophysiologic role and the knowledge of phase II clinical trials currently under development in coronary heart disease.

Leukotriene C4 synthase and ischemic cardiovascular disease and obstructive pulmonary disease in 13,000 individuals

Ischemic cardiovascular disease and obstructive pulmonary disease involve inflammation. Leukotrienes may be important pro-inflammatory mediators. We tested the hypothesis that the (-1072)G > A and (-444)A > C promoter polymorphisms of leukotriene C4 synthase confer risk of transient ischemic attack (TIA), ischemic stroke, ischemic heart disease (IHD), asthma, and chronic obstructive pulmonary disease (COPD). We genotyped individuals from the Danish general population, the Copenhagen City Heart Study, and Danish patients with IHD/coronary atherosclerosis, the Copenhagen Ischemic Heart Disease Study. We used prospective (n = 10,386), cross-sectional (n = 10,386), and case-control (n = 2392 + 5012) designs. Allele frequency was 0.07 for (-1072)A and 0.29 for (-444)C. Cumulative incidence for TIA was higher for (-1072)AA versus GG genotype (log-rank: p < 0.001), and lower for (-444)CC versus AA genotype (log-rank: p = 0.03). Cumulative incidence for ischemic stroke was also lower for (-444)CC versus AA genotype (log-rank: p = 0.04). Multifactorially adjusted hazard ratios for TIA were 5.2(95% CI:1.9-14) for (-1072)AA versus GG genotype, and 0.4(0.2-1.0) for (-444)CC versus AA genotype. Corresponding values were 1.9 (0.7-5.2) and 0.7 (0.5-1.0) for ischemic stroke, and 0.8 (0.4-1.6) and 1.0 (0.9-1.2) for IHD. In the case-control study, corresponding multifactorially adjusted odds ratios for IHD/coronary atherosclerosis were 0.5 (0.2-1.3) and 1.2 (1.0-1.5). These genotypes were not associated with risk of asthma or COPD. Leukotriene C4 synthase promoter genotypes influence risk of TIA and ischemic stroke, but not risk of IHD/coronary atherosclerosis, asthma, or COPD.

[The effect of cigarette smoking on serum activities of paraoxonase and arylesterase in stroke patients]

Cigarette smoking is one of most important modifiable risk factors of stroke. Lipids peroxidation remains crucial among pathomechanisms leading to increased risk of stroke in tobacco smokers.

AIM OF THE STUDY

To evaluate the effect of cigarette smoking on the activity of paraoxonase and arylesterase as enzymes involved in protection against oxidation of low-density lipoproteins. We have included in the study 431 subsequent stroke patients hospitalized in Department of Neurology in Poznan in a period from February 2007 to May 2008. The control group consisted of 16 healthy, nonsmoking volunteers. The activity of paraoxonase (PON) and arylesterase (ARE) in patients' sera was estimated by spectrophotometric methods. All patients admitted to emergency room underwent clinical examination. General examination, neurological examination and clinimetric assessment with the use of GCS (Glasgow Coma Scale) and NIHSS (National Institute of Health Stroke Scale) scales were performed.

RESULTS

The group of ischemic stroke patients consisted of 26.7% current smokers, 31.3%--ex-smokers, and 42% never-smokers. Among patients with hemorrhagic transformation of ischemic stroke 13.6 % actively smoked cigarettes, 22.7% were ex-smokers, and 63.7%--never-smokers. The statistical analysis of age of patients in all studied groups showed the younger onset of stroke in smokers (p < 0.0001). The activity of arylesterase was significantly disturbed by cigarette smoking in patients with ischemic stroke. In smokers with ischemic stroke ARE activity correlated negatively with number of cigarettes smoked daily (r = -0.2133; p = 0.0322). We have showed positive correlation of duration of smoking with ARE activity (r = 0.2573; p = 0.0239). In non-smoking ischemic stroke patients PON activity increased significantly (p < 0.01) comparing to controls. Tobacco smoking caused impairment of enzymatic antioxidant mechanisms related to paraoxonase activity, because there was no significant (p > 0.05) up-regulation of PON activity in smokers with ischemic stroke. The activity of arylesterase is modified by tobacco smoking in ischemic stroke patients. Smoking causes disturbances in paraoxonase--associated enzymatic antioxidant effects in ischemic stroke patients. Abnormalities of activities of antioxidant enzymes may cause earlier onset of stroke in tobacco smokers.

The effect of an exon 12 polymorphism of the human thromboxane synthase (CYP5A1) gene in stroke patients

BACKGROUND

To examine the prevalence of an exon 12 polymorphism on the human Thromboxane synthase (CYP5A1) gene.

MATERIAL/METHODS

Using sequence-specific PCR, we examined the allelic prevalence in 237 Greek patients with ischemic strokes and in 171 controls. In addition, we compared the CYP5A1 allelic prevalence in 71 patients with stroke recurrence despite Aspirin use, in comparison with patients who have not experienced recurrent stroke while taking Aspirin.

RESULTS

The frequencies of the CYP5A1*9 mutant (substitution of guanine by adenine near the heme-binding catalytic domain) and of the wild-type allele were 0.197 and 0.803, respectively; they did not differ significantly between stroke patients and controls. The wild-type allele was more frequent in the Cretan population compared to continental Greece (OR 1.80, 95% CI 1.19-2.74). The wild-type allele was more frequent among hypertensive and less frequent among diabetic stroke sufferers, respectively. The CYP5A1*9 mutant was significantly more prevalent among stroke patients with history of previous cerebrovascular attacks (p<0.01); and among those who failed secondary Aspirin prophylaxis even after adjusting for the common risk factors for cardiovascular disease (OR 1.49, 95% CI 1.06-2.11).

CONCLUSIONS

Allelic prevalence of the CYP5A1 exon 12 might differ between geographic areas within the same ethnic group, and is associated with particular characteristics of stroke patients. Allele mutations can abolish the enzymatic activity of thromboxane synthase, via impaired heme binding, associated with defective response to Aspirin used as secondary prevention, an effect independent from the conventional risk factors for cerebrovascular disease.

Phospholipase A2 in patients with noncardioembolic ischemic stroke and severe inflammatory reaction

The inflammatory reaction is characterized by increased circulatory levels of various indicators of the severity of inflammation. The objective was to investigate the value of lipoprotein-associated phospholipase A2 (Lp-PLA2) in patients with noncardioembolic ischemic stroke and severe proinflammatory reaction. There were investigated prospectively Lp-PLA2 levels in sera from 47 patients with ischemic stroke and severe inflammatory reaction (32 men and 15 women, mean age 63 +/- 4.23 years) as compared to 38 patients with ischemic stroke without inflammatory reaction (21 men and 17 women, mean age 61 +/- 5.52 years) and 114 healthy elderly controls. Lp-PLA2 levels were assessed using the diaDexus PLAC test (a noncompetitive ELISA). Out of 47 patients with ischemic stroke and severe inflammatory reaction 36 presented Lp-PLA2 high levels (79%). Lp-PLA2 was detected with high levels in 17 out of 30 patients with ischemic stroke without inflammatory reaction (45%). Patients with ischemic stroke and severe inflammatory reaction presented Lp-PLA2 with high levels more frequently than the healthy controls (RR 12.1 [95% CI. 6.22 to 19.333], p<0.0001). Levels of Lp-PLA2 were higher in subjects who experienced a stroke as compared to controls. Lp-PLA2 is a strong predictor of recurrent stroke risk and of increased risk of dying. The determination of Lp-PLA2 should be used to predict patient risk of cardiovascular disease and stroke; it does provide additional risk of inflammation when used in conjunction with the traditional markers. Lp-PLA2 might be used not only for risk stratification of stroke patients, but also as target for treatment.

Lipoprotein-associated phospholipase A2 activity and risk of recurrent stroke

BACKGROUND

Mass levels of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), a leukocyte-derived enzyme involved in the metabolism of low-density lipoprotein to pro-inflammatory mediators, are associated with prognosis after stroke. Lp-PLA(2) mass correlates only moderately with levels of Lp-PLA(2) activity. The relationship of Lp-PLA(2) activity to risk of stroke recurrence is unknown. We hypothesized that Lp-PLA(2) activity levels would predict risk of recurrence.

METHODS

In the population-based Northern Manhattan Stroke Study, first ischemic stroke patients >or=40 years were followed for recurrent stroke. Levels of Lp-PLA(2) activity were assessed in 467 patients, and categorized by quartile. Cox proportional hazard models were used to calculate hazard ratios (HR) and 95% confidence intervals (95% CI) for risk of recurrent stroke associated with marker quartiles after adjusting for demographics, vascular risk factors, and high-sensitivity C-reactive protein (hsCRP).

RESULTS

Mean age was 68.9 +/- 12.7 years; 54.6% were women; 53.3% Hispanic, 27.2% black, and 17.8% white. Median follow-up was 4.0 years, and there were 80 recurrent strokes. Compared to the lowest quartile of Lp-PLA(2) activity, those in the highest had an increased risk of recurrent stroke (adjusted HR 2.54, 95% CI 1.01-6.39).

CONCLUSION

Stroke patients with Lp-PLA(2) activity levels in the highest quartile, compared to those in the lowest quartile, had an increased risk of recurrence after first ischemic stroke. Further studies are warranted to determine whether this biomarker has clinical utility in determining high-risk populations of stroke survivors, and whether anti-inflammatory strategies that reduce levels of activity of Lp-PLA(2) reduce the risk of stroke recurrence.

The genetics of primary haemorrhagic stroke, subarachnoid haemorrhage and ruptured intracranial aneurysms in adults

Background

The genetic basis of haemorrhagic stroke has proved difficult to unravel, partly hampered by the small numbers of subjects in any single study. A meta-analysis of all candidate gene association studies of haemorrhagic stroke (including ruptured subarachnoid haemorrhage and amyloid angiopathy-related haemorrhage) was performed, allowing more reliable estimates of risk.

Methods

A systematic review and meta-analysis of all genetic studies in haemorrhagic stroke was conducted. Electronic databases were searched until and including March 2007 for any candidate gene in haemorrhagic stroke. Odds ratio (OR) and 95% confidence intervals (CI) were determined for each gene disease association using fixed and random effect models.

Results

Our meta-analyses included 6,359 cases and 13,805 controls derived from 55 case-control studies, which included 12 genes (13 polymorphisms). Statistically significant associations with haemorrhagic stroke were identified for those homozygous for the ACE/I allele (OR, 1.48; 95% CI, 1.20–1.83; p = 0.0003) and for the 5G allele in the SERPINE1 4G/5G polymorphism (OR, 1.42; 95% CI, 1.03–1.96; p = 0.03). In addition, both &b.epsi;2 and &b.epsi;4 alleles of APOE were significantly associated with lobar haemorrhage (OR, 1.81; 95% CI, 1.26–2.62; p = 0.002 and OR, 1.49; 95% 1.08–2.05; p = 0.01 respectively). Furthermore, a significant protective association against haemorrhagic stroke was found for the factor V Leiden mutation (OR, 0.30; 95% CI, 0.10–0.87; p = 0.03).

Conclusion

Our data suggests a genetic contribution to some types of haemorrhagic stroke, with no overall responsible single gene but rather supporting a polygenic aetiology . However, the evidence base is smaller compared to ischaemic stroke. Importantly, for several alleles previously found to be associated with protection from ischaemic stroke, there was a trend towards an increased risk of haemorrhagic stroke.

CART protects brain from damage through ERK activation in ischemic stroke

Cocaine and amphetamine-regulated transcript (CART) is a neuropeptide that protects brains against ischemic injury in vivo and in vitro. By using small interference RNA against CART(CARTi), this study shows that CART knockdown by CARTi downregulated exogenous and endogenous CART mRNA and protein expression in vivo and in vitro. Consequently, CART knockdown exacerbated neuronal cell death induced by oxygen and glucose deprivation (OGD). It also showed that CART knockdown increased infarct size in a mouse middle cerebral artery occlusion model. CART's protective effects are most likely mediated through the ERK 1/2 pathway, since ERK 1/2 phosphorylation, not that of p38 or JNK is activated in CART-treated neurons after OGD. Furthermore, neuroprotection of CART is abolished by CART knockdown and by pretreatment with ERK antagonist PD98059 and U0126, but not with p38 or JNK antagonists SB203580 or SP600125. These results provide further evidence that CART is an endogenous neuroprotective peptide against cerebral ischemia and it does so through the MAPK/ERK signaling pathway. Therefore, CART may be developed into a therapeutic agent for stroke-related brain injury.

Sex differences in adenosine deaminase activity of stroke patients

BACKGROUND

Adenosine deaminase (ADA) catalyzes the irreversible hydrolytic deamination of adenosine to inosine. The purpose of this study was to determine the plasma activities of total adenosine deaminase (ADA T), and its isoenzymes, ADA1 and ADA2, and ADA1/ADA2 ratio of male and female ischemic stroke patients.

METHODS

We determined activities of plasma ADA T, ADA1, ADA2 and ADA1/ADA2 ratio in 30 patients (15 men and 15 women) with acute ischemic stroke within 12 h of the onset of the attack, as well as in 30 control subjects (15 men and 15 women) of comparable age.

RESULTS

There were significant differences between the ADA1 activity and ADA1/ADA2 ratio in male and female stroke patients (p<0.05). Compared with male stroke subjects, females had higher ADA1 activity and ADA1/ADA2 ratios. There were no significant differences between activities of ADA T and ADA2 in men and women of the stroke and control groups. In addition, the Canadian Neurological Scale in men was significantly higher than that of women in the stroke group (p<0.05).

CONCLUSIONS

Our results suggest that the primary mechanism in men with ischemic stroke might involve the reduction of ADA1 activity. The reduction is probably an adaptation mechanism for induced increase in adenosine availability and protection of brain to ischemic injury.

Interaction between methylenetetrahydrofolate reductase C677T gene polymorphism and sleep duration on risk of stroke pathogenesis

OBJECTIVE

To investigate the interaction between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and sleeping duration on risk of stroke in a Chinese Han ethnic population.

METHODS

In the case-control study and epidemiological investigation, the self-reported sleep duration and MTHFR C677T polymorphism of 245 patients with cerebral infarction, 222 patients with cerebral hemorrhage and 282 controls were collected. Multiple logistic regression was performed to analyze the interaction between MTHFR C677T polymorphism and sleeping duration on risk of stroke.

RESULTS

After adjustment for major confounding variables, multiple logistic regression analysis showed that: (1) There was significant association between long sleep duration (>8 hours of sleep per night) and cerebral infarction (OR=3.90; 95% CI: 2.43-6.26), but not for cerebral hemorrhage (OR=1.16, 95% CI: 0.71-1.92). On the other hand, insomnia (sleep duration less than 6 hours) was neither associated with cerebral infarction nor hemorrhage. (2) MTHFR TT genotype increased the risk of cerebral infarction significantly (OR=2.01; 95% CI: 1.12-3.61), but not for cerebral hemorrhage (OR=1.16, 95% CI: 0.71-1.92). (3)There was a significant synergistic effect of interaction between MTHFR TT677 genotype and long sleep duration on risk of cerebral infarction (OR=6.22; 95% CI: 2.44-15.83).

CONCLUSION

MTHFR TT677 genotype and long sleep duration increase the risk of cerebral infarction independent of confounding factors, respectively. Furthermore, there is a significant synergistic effect between MTHFR TT677 genotype and long sleep duration on risk of cerebral infarction in the Chinese Han ethnic population.

Poly(ADP-ribose) polymerase activity in different pathologies--the link to inflammation and infarction

DNA repair and aging are two phenomena closely connected to each other. The poly(ADP-ribosyl)ation reaction has been implicated in both of them. Poly(ADP-ribose) was originally discovered as an enzymatic reaction product after DNA damage. Soon it became evident that it is necessary for regulation of different repair pathways. Also, evidence accumulated that poly(ADP-ribose) formation capacity is at least correlated with the life span of mammalian species. As a NAD(+)-consuming process, poly(ADP-ribosyl)ation can lead to cell death by energy depletion. This finding opened the area for investigation of poly(ADP-ribose) polymerase activity and polymer formation in pathologies. This review provides an introduction into the wide and complex field of poly(ADP-ribosyl)ation in different pathologies with regards of cell death regulation, inflammation and resulting tissue damage.

Induction of heme oxygenase-1 by traditional Chinese medicine formulation ISF-1 and its ingredients as a cytoprotective mechanism against oxidative stress

Traditional medicines are clinically used to treat post-stroke disorders in China. In search of alternative medicines for post-stroke rehabilitation, we recently identified the heme oxygenase-1 (HO-1) pathway as a key mechanism underlying the biological activities of the ischemic stroke formulation ISF-1. This study was designed to further investigate ISF-1 for HO-1 induction in cultured human cells and corresponding cytoprotective effects against oxidative injury. A rat stroke model induced by middle cerebral artery occlusion was employed to verify the activity of ISF-1 in vivo. It was found that HO-1 expression was induced by ISF-1 in a dose- and time-dependent manner. Four ingredients from ISF-1 were identified to be responsible for HO-1 induction. The appropriate combinations of these active ingredients or purified compounds resulted in synergistic induction of HO-1 expression. A minimal HO-1-inducing formulation was prepared and showed significant cytoprotection against H2O2-induced oxidative stress. Collectively, the herbal formulation ISF-1 was capable of inducing HO-1 expression, in vitro and in vivo, offering a potential mechanism for post-stroke rehabilitation. This study may shed light on the development of mechanism-defined therapies based on traditional herbal remedies.

The paraoxonase gene polymorphism in stroke patients and lipid profile

OBJECTIVES

The paraoxonase (PON) gene can reduce the risk of developing atherosclerosis. We investigated the associations between PON polymorphisms and ischemic stroke. We also investigated the associations between PON polymorphisms and lipid profile in stroke patients.

METHODS

A total of 350 patients with ischemic stroke and 242 control subjects in Korean population were genotyped for the PON1M55 L, PON1Q192R, PON2A148 G and PON2S311C polymorphisms using melting point analysis with LightCycler real-time polymerase chain reaction (PCR) technology.

RESULTS

There were no significant differences in genotype and allele distribution of the PON polymorphisms between the ischemic stroke patients and control subjects. The concentration of total homocysteine was significantly different in the PON1M55 L polymorphism (P = 0.047), and the apolipoprotein (Apo)B concentration was significantly different in the PON1Q192R polymorphism (P = 0.02) in stroke patients. The concentrations of low-density lipoprotein (LDL) cholesterol and ApoB were significantly different between the PON2A148 G (P = 0.011, P = 0.000, respectively) and PON2S311C polymorphisms (P = 0.046, P = 0.003, respectively) in stroke patients.

CONCLUSIONS

This study did not provide association between PON gene polymorphisms and ischemic stroke. However, it confirmed that the PON1L55 L allele is associated with plasma concentration of total homocysteine and that the PON2G148 G and PON2S311S allele is associated with plasma concentrations of LDL cholesterol and ApoB.

Poly(ADP-ribose)polymerase 1 (PARP-1) and postischemic brain damage

Poly(ADP-ribose)polymerases (PARPs) are enzymes that are able to catalyze the transfer of ADP-ribose units from NAD to substrate proteins and are particularly abundant in cell nuclei where they play key roles in the maintenance of genomic integrity, control of cell cycle and gene expression. Brain ischemia overactivates PARPs and PARP-deficient mice or animal treated with PARP inhibitors have a drastically reduced brain damage in various stroke models. PARP 'overactivation' occurs not only in neurons but also in astrocytes, microglial cells, endothelia, and infiltrating leukocytes. The ensuing cell death occurs through various molecular mechanisms: a) excessive ATP use for NAD synthesis and inhibition of mitochondrial function with subsequent energy failure (particularly important in neurons); b) apoptosis-inducing factor (AIF) translocation from the mitochondria to the nucleus (present in neurons, endothelial, and other cells); c) excessive expression of inflammatory mediators (well demonstrated in glial cells) or d) reduced expression of prosurvival factors. Thus PARPs seem to play key roles in postischemic brain damage and are now considered interesting targets for therapies aimed at reducing stroke pathology.

Genetic variation in cytochrome P450 2J2 and soluble epoxide hydrolase and risk of ischemic stroke in a Chinese population

OBJECTIVE

Epoxyeicosatrienoic acids have been recognized for their protective effects on the cardiovascular system. This study investigated whether two common polymorphisms in genes believed to be influential in regulating circulating levels of epoxyeicosatrienoic acids, namely cytochrome P450 2J2 (CYP2J2) G-50T and soluble epoxide hydrolase (EPHX2) G860A, were associated with ischemic stroke risk in a Chinese population.

METHODS AND RESULTS

Screening of 200 patients with ischemic stroke and 350 control participants revealed that CYP2J2-50T allele frequency was not significantly different in ischemic stroke cases versus controls. In contrast, EPHX2 860A allele frequency was 16.8% in ischemic stroke cases versus 21.7% in controls (P=0.047), and the presence of this variant allele was associated with a significantly lower risk of ischemic stroke after adjustment for sex, age and multiple cardiovascular risk factors (adjusted odds ratio=0.50, 95% confidence interval 0.29-0.86). Moreover, there was a significant interaction between the EPHX2 G860A polymorphism, smoking and ischemic stroke risk such that nonsmokers carrying the EPHX2 G860A variant allele were at the lowest risk of ischemic stroke (odds ratio=0.33, 95% confidence interval, 0.17-0.67, P=0.002), whereas no significant association was observed in smokers.

CONCLUSIONS

Collectively, these data indicate a protective influence of the G860A polymorphism of EPHX2 on ischemic stroke in Chinese nonsmokers.

[Gamma-glytamiltransferase activity and cardiovascular diseases (ischemic heart disease and cerebral stroke)]

To investigate association between gamma-glytamiltransferase levels and the development of CVD. The data were taken from materials of the epidemiological study " Determinants of cardiovascular disease in Eastern Europe " , the HAPPIE project. We investigated representative samples from non-organized population of men and women 45 - 69 years old living in Novosibirsk - 9361 subjects (4275 men and 5086 women). The program of study included: questionnaire of previous CVD, smoking status and alcohol consumption; two blood pressure measurements; anthropometry, biochemical analysis (gamma-glytamiltransferase, total cholesterol, HDL cholesterol, and triglycerides) and rest ECG. Among all subjects we distinguished three groups: first - patients with diagnosed ischemic heart disease (angina pectoris or myocardial infarction) and without previous cerebral stroke; second - patients with previous cerebral stroke (without ischemic heart disease); third - patients without previous ischemic heart disease and cerebral stroke (control group). We revealed reliable data on sex-dependent difference of gamma-glytamiltransferase activity: men have higher gamma-glytamiltransferase activity compared with women in all age groups. Subjects who didn t take alcoholic drinks during the last year have noticeably lower gamma-glytamiltransferase level than those who took alcoholic drinks during that period. Gamma-glytamiltransferase activity was higher both in men and women in group with ischemic heart disease, than in control group. We did not reveal difference in gamma-glytamiltransferase activity between groups with cerebral stroke and control group. The similar patterns were revealed in subjects who didn't take alcoholic drinks during the last year.

Soluble epoxide hydrolase: a novel therapeutic target in stroke

The P450 eicosanoids epoxyeicosatrienoic acids (EETs) are produced in brain and perform important biological functions, including protection from ischemic injury. The beneficial effect of EETs, however, is limited by their metabolism via soluble epoxide hydrolase (sEH). We tested the hypothesis that sEH inhibition is protective against ischemic brain damage in vivo by a mechanism linked to enhanced cerebral blood flow (CBF). We determined expression and distribution of sEH immunoreactivity (IR) in brain, and examined the effect of sEH inhibitor 12-(3-adamantan-1-yl-ureido)-dodecanoic acid butyl ester (AUDA-BE) on CBF and infarct size after experimental stroke in mice. Mice were administered a single intraperitoneal injection of AUDA-BE (10 mg/kg) or vehicle at 30 mins before 2-h middle cerebral artery occlusion (MCAO) or at reperfusion, in the presence and absence of P450 epoxygenase inhibitor N-methylsulfonyl-6-(2-propargyloxyphenyl) hexanamide (MS-PPOH). Immunoreactivity for sEH was detected in vascular and non-vascular brain compartments, with predominant expression in neuronal cell bodies and processes. 12-(3-Adamantan-1-yl-ureido)-dodecanoic acid butyl ester was detected in plasma and brain for up to 24 h after intraperitoneal injection, which was associated with inhibition of sEH activity in brain tissue. Finally, AUDA-BE significantly reduced infarct size at 24 h after MCAO, which was prevented by MS-PPOH. However, regional CBF rates measured by iodoantipyrine (IAP) autoradiography at end ischemia revealed no differences between AUDA-BE- and vehicle-treated mice. The findings suggest that sEH inhibition is protective against ischemic injury by non-vascular mechanisms, and that sEH may serve as a therapeutic target in stroke.

NAD(P)H oxidase p22phoxC242T polymorphism and ischemic stroke in Japan: the Fukuoka Stroke Registry and the Hisayama study

The C242T polymorphism of p22phox, a component of NAD(P)H oxidase, may have an impact on cardiovascular diseases; however, the association between this polymorphism and brain infarction is not fully understood. Here, we investigate the relationship between the C242T polymorphism and brain infarction in Japan. We recruited 1055 patients with brain infarction and 1055 control subjects. A chi-squared test revealed that the T-allele frequency was lower in patients with cardioembolic infarction (5.6%) than in control subjects (11.0%, P < 0.001); however, allele frequencies in patients with lacunar and atherothrombotic infarction (11.2%) were not significantly different from those in control subjects (11.0%). A multivariate-adjusted conditional logistic regression analysis also revealed no association between CT + TT genotype, and lacunar and atherothrombotic infarction (odds ratio = 0.97, 95% confidence interval: 0.72-1.32). To investigate the functional effects of the C242T polymorphism, we examined superoxide production in COS-7 cells cotransfected with Nox4 and p22phox of each genotype. The superoxide-producing activity in those cells expressing p22phox with the T allele was not significantly different from that in cells expressing p22phox with the C allele. The present results suggest that the p22phox C242T polymorphism may have a protective effect against cardioembolic infarction, but is not related to lacunar and atherothrombotic infarction in Japan.

Neuroprotective effects of adenosine monophosphate-activated protein kinase inhibition and gene deletion in stroke

BACKGROUND AND PURPOSE

5' adenosine monophosphate-dependent protein kinase (AMPK) acts as a metabolic sensor. AMPK is elevated under ischemic conditions, but the role of AMPK in ischemic brain remains controversial. In this study, we examined the effects of AMPK inhibition using both pharmacological and genetic approaches in an in vivo stroke model.

METHODS

Focal stroke was induced by reversible middle cerebral artery occlusion in male wild-type mice as well as mice deficient in one of the isoforms of the catalytic subunit of AMPK, AMPK alpha-1 or alpha-2.

RESULTS

AMPK inhibition was neuroprotective after focal stroke. Mice deficient in AMPK alpha-2 demonstrated significantly smaller infarct volumes compared with wild-type littermates, whereas deletion of AMPK alpha-1 had no effect. Phosphorylation of a major upstream regulator of AMPK, LKB1, was also induced in stroke brain.

CONCLUSIONS

AMPK activation is detrimental in a model of focal stroke. The AMPK catalytic isoform alpha-2 contributes to the deleterious effects of AMPK activation. AMPK inhibition leads to neuroprotection even when these agents are administered poststroke.

The phosphorylation state of eNOS modulates vascular reactivity and outcome of cerebral ischemia in vivo

NO plays critical roles in vascular function. We show that modulation of the eNOS serine 1179 (S1179) phosphorylation site affects vascular reactivity and determines stroke size in vivo. Transgenic mice expressing only a phosphomimetic (S1179D) form of eNOS show greater vascular reactivity, develop less severe strokes, and have improved cerebral blood flow in a middle cerebral artery occlusion model than mice expressing an unphosphorylatable (S1179A) form. These results provide a molecular mechanism by which multiple diverse cardiovascular risks, such as diabetes and obesity, may be centrally integrated by eNOS phosphorylation in vivo to influence blood flow and cardiovascular disease. They also demonstrate the in vivo relevance of posttranslational modification of eNOS in vascular function.

Effects of long-term administration of HMG-CoA reductase inhibitor, atorvastatin, on stroke events and local cerebral blood flow in stroke-prone spontaneously hypertensive rats

The objective of this study was to determine whether the long-term administration of an HMG-CoA reductase inhibitor, atorvastatin, confers protective effects against stroke events in stroke-prone spontaneously hypertensive rats (SHRSPs). Atorvastatin (2 mg/kg, 20 mg/kg) or vehicle was orally administered to 8-week-old SHRSPs for 11 weeks. The survival ratio and stroke incidence were calculated, and plasma lipids and plasma levels of asymmetric dimethylarginine (ADMA), a circulating endogenous competitive inhibitor of NO synthase, were measured after sacrifice. The effect of atorvastatin on local cerebral blood flow (l-CBF) was also determined in 13-week-old SHRSPs after treatment with 20 mg/kg atorvastatin daily for 5 weeks. The survival ratios at 19 weeks of age were 15, 30, and 50% in the vehicle, low-dose (2 mg/kg), and high-dose groups (20 mg/kg), respectively. The survival ratio was significantly higher in the high-dose group than in the vehicle group. The incidence of stroke was significantly lower in the high-dose group than in the vehicle group. The levels of ADMA were 0.81+/-0.18 (mean+/-S.D.), 0.62+/-0.09, and 0.61+/-0.06 micromol/l in the vehicle, low-dose, and high-dose groups, respectively. Atorvastatin administration significantly reduced the ADMA levels without affecting the levels of plasma lipids. The level of l-CBF tended to be higher in the treated group, but not to a significant extent. Thus, atorvastatin was determined to confer a protective effect against hypertension-based stroke. The data suggest that the efficacy of the statin for stroke protection may be partially involved in the improvement of endothelial function via NO production and reduction of ADMA. Statins may confer useful protection against not only atherosclerosis-based stroke, but also hypertension-based stroke.

Anterior ischemic optic neuropathy and stroke with use of PDE-5 inhibitors for erectile dysfunction: cause or coincidence?

The PDE-5 inhibitors sildenafil (Viagra) vardenafil (Levitra) and tadalafil (Cialis) have been taken by millions of men for erectile dysfunction. Transient visual symptoms are common but there also have been fourteen cases of nonarteritic anterior ischemic optic neuropathy (NAION) described in patients using these drugs as well as a few other vascular events. NAION is a common optic neuropathy in patients in the age group using these drugs and the question arises whether or not PDE-5 inhibitors are causing NAION. One case of NAION occurred after transient visual symptoms occurred with repeated use and one patient experienced a transient ischemic attack after taking a dose followed by a stroke on using the drug again later. Other than these two cases with strong dechallenge-rechallenge data, the evidence to support PDE-5 inhibitors as a cause of NAION or any vascular event is weak. PDE-5 inhibitors probably are a rare cause of a common ischemic disorder of the optic disc. They should be avoided in men who have already experienced NAION in one eye. Patients should be warned to seek medical attention if they have visual field or acuity loss after using PDE-5 inhibitors. Otherwise there is little basis for modifying the current guidelines for the use of these drugs.

[The influence of geomagnetic variations on the formation of nitric oxide in exhaled air in human]

The content of nitric oxide in exhaled air in healthy persons has been studied. It was shown that nitric oxide in exhaled air is formed from saliva nitrite due to the nitrite reductase activity of mouth cavity microflora. A relationship between the nitric oxide level and age, arterial pressure, and geomagnetic field indices was established. It was shown that the level of nitric oxide diminishes with age. A negative correlation between the nitric oxide content in exhaled air and arterial pressure (systolic and diastolic) was found. It was assumed that nitric oxide from the mouth can penetrate into the lungs and then to the blood where it can influence the vessel tonus. It was shown that the negative relationship took place between nitric oxide level in the air and Ki-indices of geomagnetic field on the day of measurement or the day preceding the measurement. The data obtained suggest that nitric oxide is involved in processes causing infarcts and insults in periods of magnetic storms.

[Glutathione system in erythrocytes and blood plasma in strokes and dyscirculatory encephalopathy]

In dyscirculatory encephalopathy and moderate ischemic stroke there are single changes of components of glutathione metabolism. In moderate and severe ischemic stroke frequent and considerable changes have been revealed. Changes in hemorrhagic stroke are also expressed. An increase of activities of glutathione peroxidase and glutathione transferase is the most typical, rarely the increase of glutathione reductase and GSH is observed. The increase of enzymes activity was absent at the delayed oneset of treatment (more than 3 days) and in severe cases patients who died later. Glutathione system is important in the tolerance to cerebral ischemia.

PON1 activity and genotype in patients with arterial ischemic stroke and in healthy individuals

OBJECTIVE

Paraoxonase-1 (PON1) is an esterase with antioxidant properties. Low PON1 enzyme activity or specific allelic polymorphisms seem to be associated with the risk of developing coronary artery disease or acute ischemic stroke (AIS). Our objective was to determine the distribution of both PON1 enzyme activity and its genotype in a group of patients with AIS.

MATERIALS AND METHODS

PON1 activity and the relative Q192R and L55M polymorphisms in the PON1 gene were assessed on 126 survivors of a first AIS and in 92 healthy subjects.

RESULTS

The genotype distribution for PON1 Q192R and L55M polymorphisms was similar in AIS patients and healthy subjects, but patients carrying the QRLL or RRLL genotype combination had lower PON1 enzyme activity compared with healthy subjects with the same genotype.

CONCLUSION

We postulate that lower than expected PON1 enzyme activity within specific genotypes might explain the reported association between R and L alleles and the risk of developing AIS.