Reactive oxygen species plasmatic levels in ischemic stroke

In Mild and Moderate Acute Ischemic Stroke, Increased Lipid Peroxidation and Lowered Antioxidant Defenses Are Strongly Associated with Disabilities and Final Stroke Core Volume

In acute ischemic stroke (AIS), there are no data on whether oxidative stress biomarkers have effects above and beyond known risk factors and measurements of stroke volume. This study was conducted in 122 mild-moderate AIS patients and 40 controls and assessed the modified ranking scale (mRS) at baseline, and 3 and 6 months later. We measured lipid hydroperoxides (LOOH), malondialdehyde (MDA), advanced oxidation protein products, paraoxonase 1 (PON1) activities and PON1 Q192R genotypes, high density lipoprotein cholesterol (HDL), sulfhydryl (-SH) groups), and diffusion-weighted imaging (DWI) stroke volume and fluid-attenuated inversion recovery (FLAIR) signal intensity. We found that (a) AIS is characterized by lower chloromethyl acetate CMPAase PON1 activity, HDL and -SH groups and increased LOOH and neurotoxicity (a composite of LOOH, inflammatory markers and glycated hemoglobin); (b) oxidative and antioxidant biomarkers strongly and independently predict mRS scores 3 and 6 months later, DWI stroke volume and FLAIR signal intensity; and (c) the PON1 Q192R variant has multiple effects on stroke outcomes that are mediated by its effects on antioxidant defenses and lipid peroxidation. Lipid peroxidation and lowered -SH and PON1-HDL activity are drug targets to prevent AIS and consequent neurodegenerative processes and increased oxidative reperfusion mediators due to ischemia-reperfusion injury.

Steroid Receptor Coactivator-Interacting Protein (SIP) Alleviates Ischemic Cerebral Infarction Damage Through the NF-κB Pathway

Ischemic stroke leads to high mortality and disability rates in humans. Cerebral ischemic injury has a severe complex pathophysiological mechanism. The abnormal release of inflammatory cytokines will cause brain tissue damage and destroy the blood-brain barrier integrity, which aggravates the process of brain injury. Therefore, attenuating the level of inflammatory response is critical for the therapy of cerebral ischemia injury. This study examined the rule of SIP treatment to support neuron protective effect after cerebral injury in an animal model of middle cerebral artery occlusion (MCAO). After ischemia/reperfusion, neurological function, neuroglia cells activation, infarction volume, brain water content, brain tissue apoptosis ratio, and inflammatory response were assessed, and quantitative PCR and western blot were also detected, respectively. Treatment of SIP ameliorated neurological dysfunction, brain infarction, brain edema, and brain cell apoptosis after MCAO operation. Overexpression SIP also suppressed pro-inflammatory cytokines release. Furthermore, the protective effect of SIP on brain injury occurs through reduced neuroglia cells activation through downregulation of the NF-κB pathway. In summary, the present work indicated that SIP prevents ischemic cerebral infarction-induced inflammation and apoptosis by blocking inflammasome activation via NF-κB signaling pathway. Those results suggest that SIP treatment is an attractive strategy for prevention of ischemic cerebral infarction.

Salidroside Ameliorates Ischemia-Induced Neuronal Injury through AMPK Dependent and Independent Pathways to Maintain Mitochondrial Quality Control

Salidroside, an active ingredient in Rhodiola rosea, has potent protective activity against cerebral ischemia. However, the mechanisms underlying its pharmacological actions are poorly understood. In this study, we employed a mouse middle cerebral artery occlusion (MCAO) and cellular oxygen and glucose deprivation (OGD) models to test the hypothesis that salidroside may restore mitochondrial quality control in neurons by modulating the relevant signaling. The results indicated that salidroside mitigated almost 40% the ischemia-induced brain infarct volumes in mice and the OGD-decreased viability of neurons to ameliorate the mitochondrial functions. Furthermore, salidroside treatment alleviated the OGD- or ischemia-induced imbalance of mitochondrial fission and fusion, mitophagy and promoted mitochondrial biogenesis in neurons by attenuating the AMPK activity. Moreover, salidroside alleviated 50% the OGD-promoted mitochondrial calcium fluorescence intensity and 5% mitochondria-associated membrane (MAM) area by down-regulating GRP75 expression independent of the AMPK signaling. Finally, similar findings were achieved in primary mouse neurons. Collectively, these data indicate that salidroside effectively restores the mitochondria dynamics, facilitates mitochondrial biogenesis by attenuating the AMPK signaling, and maintains calcium homeostasis in neurons independent of the AMPK activity.

Pharmacological or genetic inhibition of iNOS prevents cachexia-mediated muscle wasting and its associated metabolism defects

Cachexia syndrome develops in patients with diseases such as cancer and sepsis and is characterized by progressive muscle wasting. While iNOS is one of the main effectors of cachexia, its mechanism of action and whether it could be targeted for therapy remains unexplored. Here, we show that iNOS knockout mice and mice treated with the clinically tested iNOS inhibitor GW274150 are protected against muscle wasting in models of both septic and cancer cachexia. We demonstrate that iNOS triggers muscle wasting by disrupting mitochondrial content, morphology, and energy production processes such as the TCA cycle and acylcarnitine transport. Notably, iNOS inhibits oxidative phosphorylation through impairment of complexes II and IV of the electron transport chain and reduces ATP production, leading to energetic stress, activation of AMPK, suppression of mTOR, and, ultimately, muscle atrophy. Importantly, all these effects were reversed by GW274150. Therefore, our data establish how iNOS induces muscle wasting under cachectic conditions and provide a proof of principle for the repurposing of iNOS inhibitors, such as GW274150 for the treatment of cachexia.

Bioengineering CXCR4-overexpressing cell membrane functionalized ROS-responsive nanotherapeutics for targeting cerebral ischemia-reperfusion injury

Rationale: As a potentially life-threatening disorder, cerebral ischemia-reperfusion (I/R) injury is associated with significantly high mortality, especially the irreversible brain tissue damage associated with increased reactive oxygen radical production and excessive inflammation. Currently, the insufficiency of targeted drug delivery and “on-demand” drug release remain the greatest challenges for cerebral I/R injury therapy. Bioengineered cell membrane-based nanotherapeutics mimic and enhance natural membrane functions and represent a potentially promising approach, relying on selective interactions between receptors and chemokines and increase nanomedicine delivery efficiency into the target tissues.

Methods: We employed a systematic method to synthesize biomimetic smart nanoparticles. The CXCR4-overexpressing primary mouse thoracic aorta endothelial cell (PMTAEC) membranes and RAPA@HOP were extruded through a 200 nm polycarbonate porous membrane using a mini-extruder to harvest the RAPA@BMHOP. The bioengineered CXCR4-overexpressing cell membrane-functionalized ROS-responsive nanotherapeutics, loaded with rapamycin (RAPA), were fabricated to enhance the targeted delivery to lesions with pathological overexpression of SDF-1.

Results: RAPA@BMHOP exhibited a three-fold higher rate of target delivery efficacy via the CXCR4/SDF-1 axis than its non-targeting counterpart in an in vivo model. Additionally, in response to the excessive pathological ROS, nanotherapeutics could be degraded to promote “on-demand” cargo release and balance the ROS level by p-hydroxy-benzyl alcohol degradation, thereby scavenging excessive ROS and suppressing the free radical-induced focal damage and local inflammation. Also, the stealth effect of cell membrane coating functionalization on the surface resulted in extended circulation time and high stability of nanoparticles.

Conclusion: The biomimetic smart nanotherapeutics with active targeting, developed in this study, significantly improved the therapeutic efficacy and biosafety profiles. Thus, these nanoparticles could be a candidate for efficient therapy of cerebral I/R injury.

Danggui-Shaoyao-San (DSS) Ameliorates Cerebral Ischemia-Reperfusion Injury via Activating SIRT1 Signaling and Inhibiting NADPH Oxidases

Danggui-Shayao-San (DSS) is a famous Traditional Chinese Medicine formula that used for treating pain disorders and maintaining neurological health. Recent studies indicate that DSS has neuroprotective effects against ischemic brain damage but its underlining mechanisms remain unclear. Herein, we investigated the neuroprotective mechanisms of DSS for treating ischemic stroke. Adult male Sprague-Dawley (S.D.) rats were subjected to 2 h of middle cerebral artery occlusion (MCAO) plus 22 h of reperfusion. Both ethanol extract and aqueous extract of DSS (12 g/kg) were orally administrated into the rats at 30 min prior to MCAO ischemic onset. We found that 1) ethanol extract of DSS, instead of aqueous extract, reduced infarct sizes and improved neurological deficit scores in the post-ischemic stroke rats; 2) Ethanol extract of DSS down-regulated the expression of the cleaved-caspase 3 and Bax, up-regulated bcl-2 and attenuated apoptotic cell death in the ischemic brains; 3) Ethanol extract of DSS decreased the production of superoxide and peroxynitrite; 4) Ethanol extract of DSS significantly down-regulated the expression of p67^phox but has no effect on p47^phox and iNOS statistically. 5) Ethanol extract of DSS significantly up-regulated the expression of SIRT1 in the cortex and striatum of the post-ischemic brains; 6) Co-treatment of EX527, a SIRT1 inhibitor, abolished the DSS’s neuroprotective effects. Taken together, DSS could attenuate oxidative/nitrosative stress and inhibit neuronal apoptosis against cerebral ischemic-reperfusion injury via SIRT1-dependent manner.

Neuroinflammation in Primary Open-Angle Glaucoma

Primary open-angle glaucoma (POAG) is the second leading cause of irreversible blindness worldwide. Increasing evidence suggests oxidative damage and immune response defects are key factors contributing to glaucoma onset. Indeed, both the failure of the trabecular meshwork tissue in the conventional outflow pathway and the neuroinflammation process, which drives the neurodegeneration, seem to be linked to the age-related over-production of free radicals (i.e., mitochondrial dysfunction) and to oxidative stress-linked immunostimulatory signaling. Several previous studies have described a wide range of oxidative stress-related makers which are found in glaucomatous patients, including low levels of antioxidant defences, dysfunction/activation of glial cells, the activation of the NF-κB pathway and the up-regulation of pro-inflammatory cytokines, and so on. However, the intraocular pressure is still currently the only risk factor modifiable by medication or glaucoma surgery. This present review aims to summarize the multiple cellular processes, which promote different risk factors in glaucoma including aging, oxidative stress, trabecular meshwork defects, glial activation response, neurodegenerative insults, and the altered regulation of immune response.

Oxidative Stress-Mediated Blood-Brain Barrier (BBB) Disruption in Neurological Diseases

The blood-brain barrier (BBB), as a crucial gate of brain-blood molecular exchange, is involved in the pathogenesis of multiple neurological diseases. Oxidative stress is caused by an imbalance between the production of reactive oxygen species (ROS) and the scavenger system. Since oxidative stress plays a significant role in the production and maintenance of the BBB, the cerebrovascular system is especially vulnerable to it. The pathways that initiate BBB dysfunction include, but are not limited to, mitochondrial dysfunction, excitotoxicity, iron metabolism, cytokines, pyroptosis, and necroptosis, all converging on the generation of ROS. Interestingly, ROS also provide common triggers that directly regulate BBB damage, parameters including tight junction (TJ) modifications, transporters, matrix metalloproteinase (MMP) activation, inflammatory responses, and autophagy. We will discuss the role of oxidative stress-mediated BBB disruption in neurological diseases, such as hemorrhagic stroke, ischemic stroke (IS), Alzheimer’s disease (AD), Parkinson’s disease (PD), traumatic brain injury (TBI), amyotrophic lateral sclerosis (ALS), and cerebral small vessel disease (CSVD). This review will also discuss the latest clinical evidence of potential biomarkers and antioxidant drugs towards oxidative stress in neurological diseases. A deeper understanding of how oxidative stress damages BBB may open up more therapeutic options for the treatment of neurological diseases.

Therapeutic Effects of Salidroside on Cognitive Ability in Rats with Experimental Vascular Dementia

We examined the effects of salidroside on cognition in rats with vascular dementia and explored the mechanisms of its neuroprotective effects. Sprague-Dawley rats (n=60) were randomly subdivided into 3 equal groups: controls, untreated rats with vascular dementia, and rats with vascular dementia treated with salidroside (30 mg/kg for 8 weeks). Vascular dementia was provoked by bilateral occlusion of the common carotid arteries. The cognitive function was tested in the Morris water maze. Oxidation stress was assessed by the levels of superoxide dismutase and malondialdehyde assayed with standard biochemical kits. Expressions of proteins p38, p-p38, and caspase-3 were assessed by Western blotting. In untreated rats with vascular dementia, the cognitive function degraded in parallel with a decrease in superoxide dismutase, malondialdehyde accumulation, and activation the expression of p-p38 and caspase-3. Salidroside treatment significantly improved the cognitive functions in rats with vascular dementia and diminished adverse shifts in the levels of superoxide dismutase and malondialdehyde as well as the changes in the expression of p-p38 and caspase-3 in comparison with similar changes in untreated rats. Moreover, salidroside improved spatial learning and memory in rats with vascular dementia. The therapeutic effect of salidroside is probably based on its antioxidant effects and inhibition of caspase-3-mediated apoptosis via suppression of p38 MAPK signaling pathway.

Immune-Inflammatory, Metabolic, Oxidative, and Nitrosative Stress Biomarkers Predict Acute Ischemic Stroke and Short-Term Outcome

Immune-inflammatory, metabolic, oxidative, and nitrosative stress (IMO&NS) pathways and, consequently, neurotoxicity are involved in acute ischemic stroke (IS). The simultaneous assessment of multiple IMO&NS biomarkers may be useful to predict IS and its prognosis. The aim of this study was to identify the IMO&NS biomarkers, which predict short-term IS outcome. The study included 176 IS patients and 176 healthy controls. Modified Rankin scale (mRS) was applied within 8 h after IS (baseline) and 3 months later (endpoint). Blood samples were obtained within 24 h after hospital admission. IS was associated with increased white blood cell (WBC) counts, high sensitivity C-reactive protein (hsCRP), interleukin (IL-6), lipid hydroperoxides (LOOHs), nitric oxide metabolites (NOx), homocysteine, ferritin, erythrocyte sedimentation rate (ESR), glucose, insulin, and lowered iron, 25-hydroxyvitamin D [25(OH)D], total cholesterol, and high-density lipoprotein (HDL) cholesterol. We found that 89.4% of the IS patients may be correctly classified using the cumulative effects of male sex, systolic blood pressure (SBP), glucose, NOx, LOOH, 25(OH)D, IL-6, and WBC with sensitivity of 86.2% and specificity of 93.0%. Moreover, increased baseline disability (mRS ≥ 3) was associated with increased ferritin, IL-6, hsCRP, WBC, ESR, and glucose. We found that 25.0% of the variance in the 3-month endpoint (mRS) was explained by the regression on glucose, ESR, age (all positively), and HDL-cholesterol, and 25(OH)D (both negatively). These results show that the cumulative effects of IMO&NS biomarkers are associated with IS and predict a poor outcome at 3-month follow-up.

Effects of resveratrol on learning and memory in rats with vascular dementia

The purpose of the present study was to study the effects of resveratrol on cognitive function in rats with vascular dementia and to investigate the molecular mechanisms of its neuroprotective effects. Forty-five SD rats were randomly divided into 3 groups: The control group (Con group, n=15), the model group (VD group, n=15) and the resveratrol-treated VD group (Res group, n=15). The VD rats (the VD group and the Res group) were generated by bilateral common carotid artery occlusion. The rats in the Res group received daily resveratrol treatment intraperitoneally for 4 weeks. Cognitive function was tested using the Morris water maze test. The levels of SOD and MDA (oxidative stress indicators) were detected by ELISA kits. The protein expression of Bax, Bcl-2 and caspase-3 was detected by western blotting. Compared with the rats in the Con group, the rats in the VD group exhibited decreased cognitive function, significantly increased hippocampal content of MDA, Bax and caspase-3 (P<0.05), and significantly reduced hippocampal expression of SOD and Bcl-2 (P<0.05). Compared with the rats in the VD group, the rats in the Res group exhibited increased cognitive ability, reduced hippocampal content of MDA, Bax and caspase-3 (P<0.05), and increased hippocampal expression of SOD and Bcl-2 (P<0.05). Resveratrol treatment significantly improved the spatial learning and memory of the VD rats. The mechanism associated with the neuroprotective effects of resveratrol may be closely related to the inhibition of the apoptosis pathway and oxidative stress injury.

Neural Stem Cells Transfected with Reactive Oxygen Species-Responsive Polyplexes for Effective Treatment of Ischemic Stroke

Neural stem cells (NSCs), capable of ischemia-homing, regeneration, and differentiation, exert strong therapeutic potentials in treating ischemic stroke, but the curative effect is limited in the harsh microenvironment of ischemic regions rich in reactive oxygen species (ROS). Gene transfection to make NSCs overexpress brain-derived neurotrophic factor (BDNF) can enhance their therapeutic efficacy; however, viral vectors must be used because current nonviral vectors are unable to efficiently transfect NSCs. The first polymeric vector, ROS-responsive charge-reversal poly[(2-acryloyl)ethyl(p-boronic acid benzyl)diethylammonium bromide] (B-PDEA), is shown here, that mediates efficient gene transfection of NSCs and greatly enhances their therapeutics in ischemic stroke treatment. The cationic B-PDEA/DNA polyplexes can effectively transfect NSCs; in the cytosol, the B-PDEA is oxidized by intracellular ROS into negatively charged polyacrylic acid, quickly releasing the BDNF plasmids for efficient transcription and secreting a high level of BDNF. After i.v. injection in ischemic stroke mice, the transfected NSCs (BDNF-NSCs) can home to ischemic regions as efficiently as the pristine NSCs but more efficiently produce BDNF, leading to significantly augmented BDNF levels, which in turn enhances the mouse survival rate to 60%, from 0% (nontreated mice) or ≈20% (NSC-treated mice), and enables more rapid and superior functional reconstruction.

Peroxynitrite enhances self-renewal, proliferation and neuronal differentiation of neural stem/progenitor cells through activating HIF-1α and Wnt/β-catenin signaling pathway

Hypoxic/ischemic stimulation could mediate growth and differentiation of neural stem/progenitor cells (NSCs) into mature neurons but its underlying mechanisms are largely unclear. Peroxynitrite formation is considered as a crucial pathological process contributing to cerebral ischemia-reperfusion injury. In the present study, we tested the hypothesis that peroxynitrite at low concentration could function as redox signaling to promote the growth of NSCs under hypoxic/ischemic conditions. Increased NSCs proliferation was accompanied by peroxynitrite production in the rat brains with 1 h of ischemia plus 7 days of reperfusion in vivo. Cell sorting experiments revealed that endogenous peroxynitrite level affected the capacity of proliferation and self-renewal in NSCs in vitro. Hypoxia stimulated peroxynitrite production and promoted NSCs self-renewal, proliferation and neuronal differentiation whereas treatments of peroxynitrite decomposition catalysts (PDCs, FeTMPyP and FeTPPS) blocked the changes in NSCs self-renewal, proliferation and neuronal differentiation. Exogenous peroxynitrite treatment revealed similar effects to promote NSCs proliferation, self-renewal and neuronal differentiation. Furthermore, the neurogenesis-promoting effects of peroxynitrite were partly through activating HIF-1α correlated with enhanced Wnt/β-catenin signaling pathway. In conclusion, peroxynitrite could be a cellular redox signaling for promoting NSCs proliferation, self-renewal and neuronal differentiation and peroxynitrite production could contribute to neurogenesis in ischemic/hypoxic NSCs.

Oxidative stress in cerebral small vessel disease. Role of reactive species

Cerebral small vessel disease (CSVD) is a wide term describing the condition affecting perforating arterial branches as well as arterioles, venules, and capillaries. Cerebral vascular net is one of the main targets of localised oxidative stress processes causing damage to vasculature, changes in the blood flow and blood-brain barrier and, in consequence, promoting neurodegenerative alterations in the brain tissue. Numerous studies report the fact of oxidation to proteins, sugars, lipids and nucleic acids, occurring in most neurodegenerative diseases mainly in the earliest stages and correlations with the development of cognitive and motor disturbances. The dysfunction of endothelium can be caused by oxidative stress and inflammatory mechanisms as a result of reactions and processes generating extensive reactive oxygen species (ROS) production such as high blood pressure, oxidised low density lipoproteins (oxLDL), very low density lipoproteins (vLDL), diabetes, homocysteinaemia, smoking, and infections. Several animal studies show positive aspects of ROS, especially within cerebral vasculature.

Monocyte-lymphocyte cross-communication via soluble CD163 directly links innate immune system activation and adaptive immune system suppression following ischemic stroke

CD163 is a scavenger receptor expressed on innate immune cell populations which can be shed from the plasma membrane via the metalloprotease ADAM17 to generate a soluble peptide with lympho-inhibitory properties. The purpose of this study was to investigate CD163 as a possible effector of stroke-induced adaptive immune system suppression. Liquid biopsies were collected from ischemic stroke patients (n = 39), neurologically asymptomatic controls (n = 20), and stroke mimics (n = 20) within 24 hours of symptom onset. Peripheral blood ADAM17 activity and soluble CD163 levels were elevated in stroke patients relative to non-stroke control groups, and negatively associated with post-stroke lymphocyte counts. Subsequent in vitro experiments suggested that this stroke-induced elevation in circulating soluble CD163 likely originates from activated monocytic cells, as serum from stroke patients stimulated ADAM17-dependant CD163 shedding from healthy donor-derived monocytes. Additional in vitro experiments demonstrated that stroke-induced elevations in circulating soluble CD163 can elicit direct suppressive effects on the adaptive immune system, as serum from stroke patients inhibited the proliferation of healthy donor-derived lymphocytes, an effect which was attenuated following serum CD163 depletion. Collectively, these observations provide novel evidence that the innate immune system employs protective mechanisms aimed at mitigating the risk of post-stroke autoimmune complications driven by adaptive immune system overactivation, and that CD163 is key mediator of this phenomenon.

Safflor yellow B reduces hypoxia-mediated vasoconstriction by regulating endothelial micro ribonucleic acid/nitric oxide synthase signaling

Hypoxia-induced generation of vasoconstrictors reduces cerebral blood flow (CBF) while nitric oxide (NO) synthase (NOS) and microRNAs (miRNA) in endothelial cells (ECs) suppress vasoconstriction. Safflor yellow B (SYB), a natural plant compound, previously attenuated angiotensin II-mediated injury of ECs and maintained endothelial function. This study investigated the putative involvement of NOS and miRNAs in SYB-mediated resistance to hypoxia-induced vasoconstriction. In vivo, chronic hypoxia was induced in rats, and SYB was administered intravenously. In vitro, rat primary aortic ECs were cultured under oxygen and glucose deprivation. After treatment with anti-microR-199a, as well as the NOS inhibitor, N(G)-nitro-L-arginine methyl ester, SYB, or both, cell viability, NO and peroxynitrite (ONOO-) levels, NOS expression, and miRNA levels were evaluated. SYB significantly alleviated hypoxia-mediated vasoconstriction and increased CBF endothelium-dependently. SYB upregulated miR-199a, increased EC viability, decreased endothelin-1 (ET-1) levels, inhibited protein kinase C (PKC) activity, and suppressed hypoxia inducible factor-1α (HIF-1α) expression. Furthermore, the SYB-mediated reduction of inducible NOS reduced ONOO- levels. In addition, SYB downregulated miR-138 and, thereby, enhanced S100A1 and endothelial NOS activity. Hypoxia-mediated regulation of miR-138 and miR-199a inhibited endothelial NOS expression and activation, which triggered ET-1 release and vasoconstriction. Therefore, SYB treatment reduced hypoxia-induced vasoconstriction through miR-199a/endothelial NOS signaling.

Protective effects of hydrogen rich water on the intestinal ischemia/reperfusion injury due to intestinal intussusception in a rat model

This study aimed to investigate the protective effects of hydrogen rich water on the intestinal ischemia/reperfusion (I/R) injury in a rat intestinal intussusception (II) model. Ninety Sprague-Dawley rats were randomly assigned into three groups (n = 30 per group). In sham group, rats received laparotomy, and the intestine was exposed for 15 minutes without II. In I/R + saline group and I/R + hydrogen group, rats received II after laparotomy and then intestine was relocated 8 hours later, followed by immediately intraperitoneal injection of normal saline and hydrogen rich water (HRW) (5 mL/kg), respectively. One hour later, the intestine was collected for hematoxylin-eosin staining and immunohistochemistry for apoptotic cells and 8-oxo-deoxyguanosine, and blood was harvested for detection of tumor necrosis factor-α, malondialdehyde and superoxide dismutase. Hematoxylin-eosin staining showed the intestinal mucosa was significantly damaged in I/R + saline group, which was markedly attenuated after HRW treatment. The serum tumor necrosis factor-α content increased significantly in I/R + saline group, but HRW treatment reduced serum tumor necrosis factor-α content as compared to I/R + saline group (P < 0.05). Serum malondialdehyde content and 8-oxo-deoxyguanosine positive cells in the intestine increased dramatically after II, but HRW significantly reduced them in I/R+hydrogen group (P < 0.05). In addition, superoxide dismutase activity reduced markedly and apoptotic cells increased in I/R + saline group as compared to sham group, but they HRW increased superoxide dismutase activity and reduced apoptotic cells significantly in I/R + hydrogen group (P < 0.05). Our results indicate hydrogen rich water is able to attenuate II induced intestinal I/R injury via inhibiting intestinal inflammation, attenuating intestinal/serum oxidative stress and reducing apoptotic intestinal cells.

Phytochemicals in Ischemic Stroke

Stroke is the second foremost cause of mortality worldwide and a major cause of long-term disability. Due to changes in lifestyle and an aging population, the incidence of stroke continues to increase and stroke mortality predicted to exceed 12 % by the year 2030. However, the development of pharmacological treatments for stroke has failed to progress much in over 20 years since the introduction of the thrombolytic drug, recombinant tissue plasminogen activator. These alarming circumstances caused many research groups to search for alternative treatments in the form of neuroprotectants. Here, we consider the potential use of phytochemicals in the treatment of stroke. Their historical use in traditional medicine and their excellent safety profile make phytochemicals attractive for the development of therapeutics in human diseases. Emerging findings suggest that some phytochemicals have the ability to target multiple pathophysiological processes involved in stroke including oxidative stress, inflammation and apoptotic cell death. Furthermore, epidemiological studies suggest that the consumption of plant sources rich in phytochemicals may reduce stroke risk, and so reinforce the possibility of developing preventative or neuroprotectant therapies for stroke. In this review, we describe results of preclinical studies that demonstrate beneficial effects of phytochemicals in experimental models relevant to stroke pathogenesis, and we consider their possible mechanisms of action.

Acupuncture elicits neuroprotective effect by inhibiting NAPDH oxidase-mediated reactive oxygen species production in cerebral ischaemia

In the current study, we aimed to investigate whether NADPH oxidase, a major ROS-producing enzyme, was involved in the antioxidant effect of acupuncture on cognitive impairment after cerebral ischaemia. The cognitive function, infract size, neuron cell loss, level of superoxide anion and expression of NADPH oxidase subunit in hippocampus of two-vessel occlusion (2VO) rats were determined after 2-week acupuncture. Furthermore, the cognitive function and production of O2(-) were determined in the presence and absence of NADPH oxidase agonist (TBCA) and antagonist (Apocynin). The effect of acupuncture on cognitive function after cerebral ischaemia in gp91phox-KO mice was evaluated by Morris water maze. Acupuncture reduced infarct size, attenuated overproduction of O2(-), and reversed consequential cognitive impairment and neuron cell loss in 2VO rats. The elevations of gp91phox and p47phox after 2VO were significantly decreased after acupuncture treatment. However, no differences of gp91phox mRNA were found among any experimental groups. Furthermore, these beneficial effects were reversed by TBCA, whereas apocynin mimicked the effect of acupuncture by improving cognitive function and decreasing O2(-) generation. Acupuncture failed to improve the memory impairment in gp91phox KO mice. Full function of the NADPH oxidase enzyme plays an important role in neuroprotective effects against cognitive impairment via inhibition of NAPDH oxidase-mediated oxidative stress.

Serum Phenylalanine, Tyrosine, and their Ratio in Acute Ischemic Stroke: on the Trail of a Biomarker?

Fast diagnosis and appropriate treatment are of utmost importance to improving the outcome in patients with acute ischemic stroke (AIS). A rapid and sensitive blood test for ischemic stroke is required. The aim of this study was to examine the usefulness of phenylalanine (PHE) and tyrosine (TYR) as diagnostic biomarkers in AIS. Serum levels of PHE and TYR, measured using HPLC, and their ratio (PHE/TYR) were compared between 45 patients with AIS and 40 healthy control subjects. The relationship between PHE/TYR and the serum levels of several cytokines were also examined. PHE/TYR was significantly higher in AIS patients than in healthy controls (1.75 vs 1.24, p < 0.001). A receiver operating characteristic (ROC) curve analysis of PHE/TYR in AIS patients relative to healthy controls revealed promising sensitivity and specificity, which at an optimal cutoff of 1.45 were 76 and 85 %, respectively. PHE/TYR was positively correlated with interleukin (IL)-1β (r = 0.37, p = 0.011) and IL-6 (r = 0.33, p = 0.025). This study shows that PHE/TYR is highly elevated in the acute phase of AIS, and that this elevation is coupled to the inflammatory response. The ROC analysis documents the possible value of PHE/TYR as a biomarker for AIS and demonstrates its clinical potential as a blood-based test for AIS.

The Role of Oxidative Damage in the Pathogenesis and Progression of Alzheimer's Disease and Vascular Dementia

Oxidative stress (OS) has been demonstrated to be involved in the pathogenesis of the two major types of dementia: Alzheimer's disease (AD) and vascular dementia (VaD). Evidence of OS and OS-related damage in AD is largely reported in the literature. Moreover, OS is not only linked to VaD, but also to all its risk factors. Several researches have been conducted in order to investigate whether antioxidant therapy exerts a role in the prevention and treatment of AD and VaD. Another research field is that pertaining to the heat shock proteins (Hsp_s), that has provided promising findings. However, the role of OS antioxidant defence system and more generally stress responses is very complex. Hence, research on this topic should be improved in order to reach further knowledge and discover new therapeutic strategies to face a disorder with such a high burden which is dementia.

Tim-3 cell signaling and iNOS are involved in the protective effects of ischemic postconditioning against focal ischemia in rats

The protective effect of ischemic postconditioning (IPostC) against stroke has been well-established, and the underlying mechanisms are known to involve inhibited-inflammation and free radical production. Nevertheless, how IPostC affects protein expression of iNOS, nitrotyrosine, and COX-2 has not been characterized. In addition, the role of the galectin-9/Tim-3 cell signaling pathway--a novel inflammatory pathway--in IPostC has not been studied. We examined whether iNOS, nitrotyrosine, and COX-2, as well as galectin-9/Tim-3 are involved in the protective effects of IpostC in a rat focal ischemia model. Western blot and confocal immunofluoresent staining results indicate that IPostC significantly inhibited Tim-3 expression, and that galectin-9 expression was also inhibited. In addition, IPostC attenuated production of iNOS and nitrotyrosine, but not COX-2, suggesting that IPostC has distinct effects on these inflammatory factors. Furthermore, the inflammation inhibitor minocycline blocked Tim-3 and iNOS expression induced by stroke. Taken together, we show that the galectin-9/Tim-3 cell signaling pathway is involved in inflammation induced by stroke, and IPostC may reduce infarction by attenuating this novel pathway as well as the inflammatory factors iNOS and nitrotyrosine, but not COX-2.

The use of ADSCs as a treatment for chronic stroke

Stroke is one of the disorders for which clinically effective therapeutic modalities are most needed, and numerous ways have been explored to attempt to investigate their feasibilities. However, ischemic- or hemorrhagic-induced inflammatory neuron death causes irreversible injuries and infarction regions, and there are currently no truly effective drugs available as therapy. It is therefore urgent to be able to provide a fundamental treatment method to regenerate neuronal brain cells, and therefore, the use of stem cells for curing chronic stroke could be a major breakthrough development. In this review, we describe the features and classification of stroke and focus on the benefits of adipose tissue-derived stem cells and their applications in stroke animal models. The results show that cell-based therapies have resulted in significant improvements in neuronal behaviors and functions through different molecular mechanisms, and no safety problems have so far arisen after transplantation. Further, we propose a clinical possibility to create a homing niche by reducing the degree of invasive intracerebroventricular transplantation and combining it with continuous intravenous administration to achieve a complete cure.

Pathogenesis of acute stroke and the role of inflammasomes

Inflammation is an innate immune response to infection or tissue damage that is designed to limit harm to the host, but contributes significantly to ischemic brain injury following stroke. The inflammatory response is initiated by the detection of acute damage via extracellular and intracellular pattern recognition receptors, which respond to conserved microbial structures, termed pathogen-associated molecular patterns or host-derived danger signals termed damage-associated molecular patterns. Multi-protein complexes known as inflammasomes (e.g. containing NLRP1, NLRP2, NLRP3, NLRP6, NLRP7, NLRP12, NLRC4, AIM2 and/or Pyrin), then process these signals to trigger an effector response. Briefly, signaling through NLRP1 and NLRP3 inflammasomes produces cleaved caspase-1, which cleaves both pro-IL-1β and pro-IL-18 into their biologically active mature pro-inflammatory cytokines that are released into the extracellular environment. This review will describe the molecular structure, cellular signaling pathways and current evidence for inflammasome activation following cerebral ischemia, and the potential for future treatments for stroke that may involve targeting inflammasome formation or its products in the ischemic brain.

Effects of hydrogen-rich saline on taurocholate-induced acute pancreatitis in rat

Oxidative stress plays an important role in the pathogenesis of acute pancreatitis (AP). As an ideal exterminator of poisonous free radicals, hydrogen can clearly reduce the degree of oxidative damage caused by severe acute pancreatitis (SAP) and lessen the presence of inflammatory cytokines. The aim of this study was to investigate the effects and mechanism of hydrogen-rich saline on SAP in rats. Serum TNF- α , IL-6, and IL-18 and histopathological score in the pancreas were reduced after hydrogen-rich saline treatment. Malondialdehyde (MDA) and myeloperoxidase (MPO) contents were obviously reduced, while superoxide dismutase (SOD) and glutathione (GSH) contents were increased after hydrogen-rich saline treatment. The expression of mRNA of tumor necrosis factor- α (TNF- α ) and intercellular adhesion molecule-1 (ICAM-1) in the pancreas was reduced in hydrogen-rich saline treated group. In conclusion, intravenous hydrogen-rich saline injections could attenuate the severity of AP, probably via inhibiting the oxidative stress and reducing the presence of inflammatory mediators.

Targeting reactive nitrogen species: a promising therapeutic strategy for cerebral ischemia-reperfusion injury

Ischemic stroke accounts for nearly 80% of stroke cases. Recanalization with thrombolysis is a currently crucial therapeutic strategy for re-building blood supply, but the thrombolytic therapy often companies with cerebral ischemia-reperfusion injury, which are mediated by free radicals. As an important component of free radicals, reactive nitrogen species (RNS), including nitric oxide (NO) and peroxynitrite (ONOO(-)), play important roles in the process of cerebral ischemia-reperfusion injury. Ischemia-reperfusion results in the production of nitric oxide (NO) and peroxynitrite (ONOO(-)) in ischemic brain, which trigger numerous molecular cascades and lead to disruption of the blood brain barrier and exacerbate brain damage. There are few therapeutic strategies available for saving ischemic brains and preventing the subsequent brain damage. Recent evidence suggests that RNS could be a therapeutic target for the treatment of cerebral ischemia-reperfusion injury. Herein, we reviewed the recent progress regarding the roles of RNS in the process of cerebral ischemic-reperfusion injury and discussed the potentials of drug development that target NO and ONOO(-) to treat ischemic stroke. We conclude that modulation for RNS level could be an important therapeutic strategy for preventing cerebral ischemia-reperfusion injury.

Ischemic postconditioning alleviates neuronal injury caused by relief of carotid stenosis in a rat model of cerebral hypoperfusion

The effects of early relief of heavy bilateral carotid stenosis and ischemic postconditioning on hippocampus CA1 neurons are still unclear. In this study, we used a rat model to imitate severe bilateral carotid stenosis in humans. The rats were divided into sham group, carotid stenosis group, stenosis relief group and ischemic postconditioning group. Ischemic postconditioning consisted of three cycles of 30 s ischemia and 30 s reperfusion. The cerebral blood flow was measured with a laser Doppler flowmeter. Neuronal death in the CA1 region was observed by hematoxylin-eosin staining, and the number of live neurons was assessed by cell counting under a light microscope. The levels of oxidative products MDA and 8-iso-PGF2α, inflammatory factors IL-1β and TNF-α, and the activities of anti-oxidative enzymes SOD and CAT were assayed by specific enzyme-linked immunosorbent assay (ELISA) kits, respectively. We found that relief of carotid stenosis and ischemic postconditioning could increase cerebral blood flow. When stenosis was relieved, the percentage of live neurons was 66.6% ± 6.2% on day 3 and 62.3% ± 9.8% on day 27, which was significantly higher than 55.5% ± 4.8% in stenosis group. Ischemic postconditioning markedly improved the live neurons to 92.5% ± 6.7% on day 3 and 88.6% ± 9.1% on day 27. Further study showed that, neuronal death caused by relief of stenosis is associated with increased oxidative stress and enhanced inflammatory response, and the protection of ischemic postconditioning is related to inhibition of oxidative stress and suppression of inflammatory response.

Remote ischemic perconditioning is effective alone and in combination with intravenous tissue-type plasminogen activator in murine model of embolic stroke

BACKGROUND AND PURPOSE

Remote ischemic conditioning is cardioprotective in myocardial infarction and neuroprotective in mechanical occlusion models of stroke. However, there is no report on its therapeutic potential in a physiologically relevant embolic stroke model (embolic middle cerebral artery occlusion) in combination with intravenous tissue-type plasminogen activator (tPA).

METHODS

We tested remote ischemic perconditioning therapy (RIPerC) at 2 hours after embolic middle cerebral artery occlusion in the mouse with and without intravenous tPA at 4 hours. We assessed cerebral blood flow up to 6 hours, neurological deficits, injury size, and phosphorylation of Akt (Serine(473)) as a prosurvival signal in the ischemic hemisphere at 48 hours poststroke.

RESULTS

RIPerC therapy alone improved the cerebral blood flow and neurological outcomes. tPA alone at 4 hours did not significantly improve the neurological outcome even after successful thrombolysis. Individual treatments with RIPerC and intravenous tPA reduced the infarct size (25.7% and 23.8%, respectively). Combination therapy of RIPerC and tPA resulted in additive effects in further improving the neurological outcome and reducing the infarct size (50%). All the therapeutic treatments upregulated phosphorylation of Akt in the ischemic hemisphere.

CONCLUSIONS

RIPerC is effective alone after embolic middle cerebral artery occlusion and has additive effects in combination with intravenous tPA. RIPerC may be a simple, safe, and inexpensive combination therapy with intravenous tPA.

The chronic protective effects of limb remote preconditioning and the underlying mechanisms involved in inflammatory factors in rat stroke

We recently demonstrated that limb remote preconditioning (LRP) protects against focal ischemia measured 2 days post-stroke. Here, we studied whether LRP provides long-term protection and improves neurological function. We also investigated whether LRP transmits its protective signaling via the afferent nerve pathways from the preconditioned limb to the ischemic brain and whether inflammatory factors are involved in LRP, including the novel galectin-9/Tim-3 inflammatory cell signaling pathway, which induces cell death in lymphocytes. LRP in the left hind femoral artery was performed immediately before stroke. LRP reduced brain injury size both at 2 days and 60 days post-stroke and improved behavioral outcomes for up to 2 months. The sensory nerve inhibitors capsaicin and hexamethonium, a ganglion blocker, abolished the protective effects of LRP. In addition, LRP inhibited edema formation and blood-brain barrier (BBB) permeability measured 2 days post-stroke. Western blot and immunostaining analysis showed that LRP inhibited protein expression of both galectin-9 and T-cell immunoglobulin domain and mucin domain 3 (Tim-3), which were increased after stroke. In addition, LRP decreased iNOS and nitrotyrosine protein expression after stroke. In conclusion, LRP executes long-term protective effects against stroke and may block brain injury by inhibiting activities of the galectin-9/Tim-3 pathway, iNOS, and nitrotyrosine.

Effect of consumption of dark chocolate on oxidative stress in lipoproteins and platelets in women and in men

The goal of this research was to investigate the effects of 3 weeks consumption of 50 g flavonoid-rich dark chocolate on lipoprotein oxidative stress in vitro and in vivo in 25 women compared to 25 men. Levels of thiobarbituric acid-reactive substances, conjugated dienes and hydroperoxide levels in HDL and LDL before and after consumption of dark chocolate were determined. Moreover in platelets of the same subjects NO and peroxynitrite levels were studied. TBARs concentration in women's HDL decreased by 26.7% while in men's HDL 23.4%; lipid hydroperoxides decreased in women's HDL by 62.8% while in men's HDL they decreased by 21.1%. Conjugate diene formation decreased in women's HDL by 55.9%, while in men's HDL it decreased by 49.2%. Moreover TBARs concentration decreased in women's LDL by 26.7% after supplementation and in men's LDL by 21.6%; lipid hydroperoxides decreased in women's LDL by 83.6% while in men's LDL they decreased by 64.7%. Moreover conjugate diene formation decreased in women's LDL by 48.2%, while in men's LDL it decreased by 21.6%. After supplementation peroxynitrite values decreased in women by 24% and in men by 18.6% while NO increased after supplementation by 15.7% compared to basal determination in women, and by 32.2% in men. This study showed that a short-term intake of dark chocolate might improve the lipoprotein profile in healthy humans, more so in women than in men, and this might exert a protective effect on the cardiovascular system.

Oxidative stress in ischaemic stroke

BACKGROUND

Production of reactive oxygen species after ischaemic stroke may enhance tissue damage through multiple molecular pathways.

MATERIALS AND METHODS

In this study, we examined the serum levels of lipoperoxide and hydroperoxide, conjugated dienes and total antioxidant capacity levels in 50 patients with acute ischaemic stroke (T0) to evaluate the possibility to use them as specific biochemical markers for cerebral ischaemia. Determinations were repeated after a month (T1) to correlate their relative changes with clinical evolution.

RESULTS

Lipoperoxide, hydroperoxide and conjugated diene levels in platelets were significantly higher in the early stages with respect to their late evaluation. On the contrary, total antioxidant capacity showed a significant increase at T1 with respect to T0. A significant negative correlation between total antioxidant capacity and NIHSS score at T0 and T1 was found. There was a significant positive correlation between lipoperoxide, hydroperoxide and conjugated dienes levels and NIHSS score at T0 and at T1.

CONCLUSIONS

These findings suggest that changes in free radical generation and consequent oxidative stress may have a role in the pathogenesis of acute ischaemic lesions. The activation of defence mechanisms like total antioxidant capacity could be involved in the limitation of ischaemic damage progression.

Intermittent hypoxia-induced cognitive deficits are mediated by NADPH oxidase activity in a murine model of sleep apnea

BACKGROUND

In rodents, exposure to intermittent hypoxia (IH), a hallmark of obstructive sleep apnea (OSA), is associated with neurobehavioral impairments, increased apoptosis in the hippocampus and cortex, as well as increased oxidant stress and inflammation. Excessive NADPH oxidase activity may play a role in IH-induced CNS dysfunction.

METHODS AND FINDINGS

The effect of IH during light period on two forms of spatial learning in the water maze and well as markers of oxidative stress was assessed in mice lacking NADPH oxidase activity (gp91phox(_/Y)) and wild-type littermates. On a standard place training task, gp91phox(_/Y) displayed normal learning, and were protected from the spatial learning deficits observed in wild-type littermates exposed to IH. Moreover, anxiety levels were increased in wild-type mice exposed to IH as compared to room air (RA) controls, while no changes emerged in gp91phox(_/Y) mice. Additionally, wild-type mice, but not gp91phox(_/Y) mice had significantly elevated levels of NADPH oxidase expression and activity, as well as MDA and 8-OHDG in cortical and hippocampal lysates following IH exposures.

CONCLUSIONS

The oxidative stress responses and neurobehavioral impairments induced by IH during sleep are mediated, at least in part, by excessive NADPH oxidase activity, and thus pharmacological agents targeting NADPH oxidase may provide a therapeutic strategy in sleep-disordered breathing.

Multiple aberrations in shared inflammatory and oxidative & nitrosative stress (IO&NS) pathways explain the co-association of depression and cardiovascular disorder (CVD), and the increased risk for CVD and due mortality in depressed patients

There is evidence that there is a bidirectional relationship between major depression and cardiovascular disorder (CVD): depressed patients are a population at risk for increased cardiac morbidity and mortality, and depression is more frequent in patients who suffer from CVD. There is also evidence that inflammatory and oxidative and nitrosative stress (IO&NS) pathways underpin the common pathophysiology of both CVD and major depression. Activation of these pathways may increase risk for both disorders and contribute to shared risk. The shared IO&NS pathways that may contribute to CVD and depression comprise the following: increased levels of pro-inflammatory cytokines, like interleukin-1β (IL-1β), IL-2, IL-6, IL-8, IL-12, tumor necrosis factor-α, and interferon-γ; T cell activation; increased acute phase proteins, like C-reactive protein, haptoglobin, fibrinogen and α1-antitrypsin; complement factors; increased LPS load through bacterial translocation and subsequent gut-derived inflammation; induction of indoleamine 2,3-dioxygenase with increased levels of tryptophan catabolites; decreased levels of antioxidants, like coenzyme Q10, zinc, vitamin E, glutathione and glutathione peroxidase; increased O&NS characterized by oxidative damage to low density lipoprotein (LDL) and phospholipid inositol, increased malondialdehyde, and damage to DNA and mitochondria; increased nitrosative stress; and decreased ω3 polyunsaturated fatty acids (PUFAs). The complex interplay between the abovementioned IO&NS pathways in depression results in pro-atherogenic effects and should be regarded as a risk factor to future clinical CVD and due mortality. We suggest that major depression should be added as a risk factor to the Charlson "comorbidity" index. It is advised that patients with (sub)chronic or recurrent major depression should routinely be assessed by serology tests to predict if they have an increased risk to cardiovascular disorders.

The protective role of hydrogen-rich saline in experimental liver injury in mice

BACKGROUND & AIMS

Reactive oxygen species (ROS) are considered to play a prominent causative role in the development of various hepatic disorders. Antioxidants have been effectively demonstrated to protect against hepatic damage. Hydrogen (H(2)), a new antioxidant, was reported to selectively reduce the strongest oxidants, such as hydroxyl radicals (·OH) and peroxynitrite (ONOO(-)), without disturbing metabolic oxidation-reduction reactions or disrupting ROS involved in cell signaling. In place of H(2) gas, hydrogen-rich saline (HS) may be more suitable for clinical application. We herein aim to verify its protective effects in experimental models of liver injury.

METHODS

H(2) concentration in vivo was detected by hydrogen microelectrode for the first time. Liver damage, ROS accumulation, cytokine levels, and apoptotic protein expression were, respectively, evaluated after GalN/LPS, CCl(4), and DEN challenge. Simultaneously, CCl(4)-induced hepatic cirrhosis and DEN-induced hepatocyte proliferation were measured.

RESULTS

HS significantly increased hydrogen concentration in liver and kidney tissues. As a result, acute liver injury, hepatic cirrhosis, and hepatocyte proliferation were reduced through the quenching of detrimental ROS. Activity of pro-apoptotic players, such as JNK and caspase-3, were also inhibited.

CONCLUSIONS

HS could protect against liver injury and also inhibit the processes leading to liver cirrhosis and hepatocyte compensatory proliferation.

Oral administration of mannitol may be an effective treatment for ischemia-reperfusion injury

Inhalation of hydrogen gas has been proved to be an effective treatment for ischemia-reperfusion injury. There has been considerable evidence of hydrogen's protective effect to diseases related to oxidative injury, such as the ischemia-reperfusion injury of the brain, liver and heart. Our previous studies demonstrated that intraperitoneal injection of hydrogen-rich saline protected hypoxic-ischemic brain injury, myocardial and intestine ischemia-reperfusion injury in rats. Bacteria in the large intestinal can produce endogenous hydrogen, and our preliminary experiments revealed that oral administration of mannitol in humans and animals can significantly increase the level of endogenous hydrogen. Therefore, we speculated that oral administration of mannitol may be effective against ischemia-reperfusion injury, which is a convenient, effective and unique treatment for ischemia-reperfusion injury.

Modulation of NADPH oxidase activation in cerebral ischemia/reperfusion injury in rats

NADPH oxidase is a major complex that produces reactive oxygen species (ROSs) during the ischemic period and aggravates brain damage and cell death after ischemic injury. Although many approaches have been tested for preventing production of ROSs by NADPH oxidase in ischemic brain injury, the regulatory mechanisms of NADPH oxidase activity after cerebral ischemia are still unclear. The aim of this study is identifying apocynin as a critical modulator of NADPH oxidase and elucidating its role as a neuroprotectant in an experimental model of brain ischemia in rat. Treatment of apocynin 5min before of reperfusion attenuated cerebral ischemia in rats. Administration of apocynin showed marked reduction in infarct size compared with that of control rats. Medial carotid artery occlusion (MCAo)-induced cerebral ischemia was also associated with an increase in, nitrotyrosine formation, as well as IL-1β expression, IκB degradation and ICAM expression in ischemic regions. These expressions were markedly inhibited by the treatment of apocynin. We also demonstrated that apocynin reduces levels of apoptosis (TUNEL, Bax and Bcl-2 expression) resulting in a reduction in the infarct volume in ischemia-reperfusion brain injury. This new understanding of apocynin induced adaptation to ischemic stress and inflammation could suggest novel avenues for clinical intervention during ischemic and inflammatory diseases.

Role of Rac1 GTPase in NADPH oxidase activation and cognitive impairment following cerebral ischemia in the rat

Background

Recent work by our laboratory and others has implicated NADPH oxidase as having an important role in reactive oxygen species (ROS) generation and neuronal damage following cerebral ischemia, although the mechanisms controlling NADPH oxidase in the brain remain poorly understood. The purpose of the current study was to examine the regulatory and functional role of the Rho GTPase, Rac1 in NADPH oxidase activation, ROS generation and neuronal cell death/cognitive dysfunction following global cerebral ischemia in the male rat.

Methodology/Principal Findings

Our studies revealed that NADPH oxidase activity and superoxide (O₂⁻) production in the hippocampal CA1 region increased rapidly after cerebral ischemia to reach a peak at 3 h post-reperfusion, followed by a fall in levels by 24 h post-reperfusion. Administration of a Rac GTPase inhibitor (NSC23766) 15 min before cerebral ischemia significantly attenuated NADPH oxidase activation and O₂⁻ production at 3 h after stroke as compared to vehicle-treated controls. NSC23766 also attenuated “in situ” O₂⁻ production in the hippocampus after ischemia/reperfusion, as determined by fluorescent oxidized hydroethidine staining. Oxidative stress damage in the hippocampal CA1 after ischemia/reperfusion was also significantly attenuated by NSC23766 treatment, as evidenced by a marked attenuation of immunostaining for the oxidative stress damage markers, 4-HNE, 8-OHdG and H2AX at 24 h in the hippocampal CA1 region following cerebral ischemia. In addition, Morris Water maze testing revealed that Rac GTPase inhibition after ischemic injury significantly improved hippocampal-dependent memory and cognitive spatial abilities at 7–9 d post reperfusion as compared to vehicle-treated animals.

Conclusions/Significance

The results of the study suggest that Rac1 GTPase has a critical role in mediating ischemia/reperfusion injury-induced NADPH oxidase activation, ROS generation and oxidative stress in the hippocampal CA1 region of the rat, and thus contributes significantly to neuronal degeneration and cognitive dysfunction following cerebral ischemia.

Nitric oxide platelet production in spontaneous miscarriage in the first trimester

OBJECTIVE

To investigate the role played by platelet nitric oxide (NO) metabolism in patients with spontaneous miscarriage (SM) and recurrent spontaneous miscarriage (RSM) compared with healthy pregnant women.

DESIGN

Retrospective case-control study.

SETTING

Patients and controls in an academic research environment.

INTERVENTION(S)

None.

PATIENT(S)

Thirty singleton pregnant women who experienced SM, nine singleton pregnant women who presented with RSM, and 30 singleton healthy pregnant women matched for age, parity, and gestational age were enrolled.

MAIN OUTCOME MEASURE(S)

NO levels and peroxynitrite (ONOO(-)) production; moreover, inducible NO synthase (iNOS), endothelial NO synthase (eNOS), and nitrotyrosine expression (N-Tyr) were observed in the same samples.

RESULT(S)

A significant increase was shown in platelet NO and ONOO(-) levels and in iNOS and N-Tyr both in SM and in RSM pregnant women compared with controls.

CONCLUSION(S)

The data herein reported imply that a modified NO pathway might play a key role in the physiological changes of advancing gestation but may also contribute to the pathophysiology of spontaneous miscarriage. Thus, any factors balancing NO metabolism might be useful in the treatment of miscarriage, thus reducing the substantial morbidity and associated mortality.

Oxidative risk for atherothrombotic cardiovascular disease

In the vasculature, reactive oxidant species, including reactive oxygen, nitrogen, or halogenating species, and thiyl, tyrosyl, or protein radicals may oxidatively modify lipids and proteins with deleterious consequences for vascular function. These biologically active free radical and nonradical species may be produced by increased activation of oxidant-generating sources and/or decreased cellular antioxidant capacity. Once formed, these species may engage in reactions to yield more potent oxidants that promote transition of the homeostatic vascular phenotype to a pathobiological state that is permissive for atherothrombogenesis. This dysfunctional vasculature is characterized by lipid peroxidation and aberrant lipid deposition, inflammation, immune cell activation, platelet activation, thrombus formation, and disturbed hemodynamic flow. Each of these pathobiological states is associated with an increase in the vascular burden of free radical species-derived oxidation products and, thereby, implicates increased oxidant stress in the pathogenesis of atherothrombotic vascular disease.