Uric acid administration in patients with acute stroke: a novel approach to neuroprotection

A cross-sectional analysis of the relationship between ischemic stroke and uric acid in young people in highland areas

Objective

To investigate the relationship between serum uric acid (SUA) levels and ischemic stroke in young patients in the Ganzi Tibetan plateau area.

Methods

A cross-sectional survey was undertaken from January 2020 to June 2023 involving young patients (age: 15-45 years) diagnosed with ischemic stroke. The survey was conducted at the Department of Internal Medicine of the People's Hospital of Derong County, Ganzi Prefecture. The participants underwent a comprehensive assessment, including questionnaire surveys, physical examinations, laboratory tests, and head computed tomography (CT) examinations. Based on the tertiles of serum uric acid (SUA) levels, the patients were stratified into three groups. Furthermore, stroke severity was classified into mild (1-4 points), moderate (5-15 points), and severe (>15 points) categories using the National Institute of Health Stroke Scale.

Results

The severe stroke group exhibited higher levels of age, glucose, systolic blood pressure, serum triglyceride, low-density lipoprotein cholesterol, and serum uric acid (SUA) compared to the mild stroke group (P < 0.05). Furthermore, the likelihood of male sex, advanced age, smoking, and a family history of stroke, diabetes mellitus, and heart disease were significantly elevated in the severe stroke group compared to the moderate stroke group (P < 0.05). Multivariate logistic regression analysis conducted on young adults residing in highland areas revealed a significant association between SUA levels and the risk of stroke.

Conclusion

Elevated SUA levels serve as a distinct risk factor for the development of a major stroke in young patients in highland areas. At SUA levels of 320.56 mol/L, the risk of a moderate-to-severe stroke is noticeably elevated.

Evaluation of Cisplatin-Induced Acute Renal Failure Amelioration Using Fondaparinux and Alteplase

Acute renal failure (ARF) is a deleterious condition with increased mortality or healthcare costs or dialysis-dependent end-stage renal disease. The study aims to compare prophylaxis with fondaparinux (Fund) vs. treatment with alteplase (Alt) in ameliorating cisplatin (Cis)-induced ARF. Sixty male mice were equally divided randomly into six groups of control, Cis, Alt, and Cis + Alt groups receiving normal saline for 10 days. All four groups except for the control received Cis (30 mg/kg, i.p.) on day 7, and 6 h later, both the Alt groups received Alt (0.9 mg/kg, i.v.). The animal groups Fund and Fund + Cis received Fund (5 mg/kg, i.p.) for 10 days, and the Fund + Cis group on day 7 received Cis. All the animal groups were euthanized 72 h after the Cis dose. The Fund + Cis group showed significantly increased expression levels of platelet count, retinoid X receptor alpha (RXR-α) and phosphorylated Akt (p-Akt) in addition to decreased levels of urea, blood urea nitrogen (BUN), uric acid, white blood cells (WBCs), red blood cells (RBCs), relative kidney body weight, kidney injury score, glucose, prothrombin (PT), A Disintegrin And Metalloproteinases-10 (ADAM10), extracellular matrix deposition, protease-activated receptor 2 (PAR-2), and fibrinogen expression when compared to the Cis-only group. Meanwhile, the Cis + Alt group showed increased caspase-3 expression in addition to decreased levels of urea, BUN, uric acid, WBCs, RBCs, glucose, platelet count and PT expression with a marked decrease in PAR-2 protein expression compared to the Cis group. The creatinine levels for both the Fund + Cis and Cis + Alt groups were found to be comparable to those of the Cis-only group. The results demonstrate that the coagulation system's activation through the stimulation of PAR-2 and fibrinogen due to Cis-induced ADAM10 protein expression mediated the apoptotic pathway, as indicated by caspase-3 expression through the p-Akt pathway. This is normally accompanied by the loss of RXR-α distal and proximal tubules as lipid droplets. When the animals were pre-treated with the anticoagulant, Fund, the previous deleterious effect was halted while the fibrinolytic agent, Alt, most of the time failed to treat Cis-induced toxicity.

Relationship Between Change in Serum Uric Acid and Ischemic Stroke in Chinese Hypertensive Patients

Background: Limited studies focused on the association between serum uric acid (SUA) change with ischemic stroke, and their results remain controversial. The present study aimed to investigate the relationship between change in SUA with ischemic stroke among hypertensive patients.

Method: This was a retrospective cohort study. We recruited adult hypertensive patients who had two consecutive measurements of SUA levels from 2013 to 2014 and reported no history of stroke. Change in SUA was assessed as SUA concentration measured in 2014 minus SUA concentration in 2013. Multivariable Cox proportional hazards models were used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). The Kaplan–Meier analysis and log-rank test were performed to quantify the difference in cumulative event rate. Additionally, subgroup analysis and interaction tests were conducted to investigate heterogeneity.

Results: A total of 4,628 hypertensive patients were included, and 93 cases of ischemic stroke occurred during the mean follow-up time of 3.14 years. Participants were categorized into three groups according to their SUA change tertiles [low (SUA decrease substantially): <-32.6 μmol/L; middle (SUA stable): ≥-32.6 μmol/L, <40.2 μmol/L; high (SUA increase substantially): ≥40.2 μmol/L]. In the fully adjusted model, setting the SUA stable group as reference, participants in the SUA increase substantially group had a significantly elevated risk of ischemic stroke [HR (95% CI), 1.76 (1.01, 3.06), P = 0.0451], but for the SUA decrease substantially group, the hazard effect was insignificant [HR (95% CI), 1.31 (0.75, 2.28), P = 0.3353]. Age played an interactive role in the relationship between SUA change and ischemic stroke. Younger participants (age < 65 years) tended to have a higher risk of ischemic stroke when SUA increase substantially.

Conclusion: SUA increase substantially was significantly correlated with an elevated risk of ischemic stroke among patients with hypertension.

Uric acid played a role in the association between gender and deep vein thrombosis in patients with stroke

BACKGROUND AND AIMS

Gender-specific differences were found in serum uric acid (SUA) levels and the risk of isolated distal deep vein thrombosis (IDDVT). This study aimed to explore the association among gender, SUA, and IDDVT in stroke patients.

METHODS AND RESULTS

Finally, 3404 patients were recruited and divided into two groups: IDDVT (n = 1233) and Non-IDDVT (n = 2171) groups. Propensity score matching (PSM) was conducted to match the patients. Binary logistic regression was adopted to explore the association between SUA and IDDVT, with the SUA divided into quartiles. After PSM, 975 patients were included in each group. Non-IDDVT group had a larger proportion of male than IDDVT group (64.9% vs. 52.7%, p < 0.001). Moreover, males showed higher SUA levels than females (316.7 ± 102.1 vs. 261.8 ± 94.0 μmol/L, t = 12.1, p < 0.001). The highest quartile of SUA (≥346 μmol/L) showed a lower risk of IDDVT (OR = 0.629, p = 0.001), while the lowest quartile (≤225 μmol/L) showed a higher risk of IDDVT (OR = 1.361, p = 0.022).

CONCLUSION

In patients with stroke, SUA played a protective role in IDDVT. Females had a higher risk of IDDVT, which may be owing to the lower SUA levels than males. In clinical practice, more attention should be paid to the risk of IDDVT in females, especially those with lower SUA levels.

Different associations between serum urate and diabetic complications in men and postmenopausal women

AIMS

The objective of this study was to investigate the different associations of the serum urate (SUA) level with cardiovascular and cerebrovascular diseases (CVD), diabetic kidney disease (DKD) and diabetic retinopathy (DR) in Chinese adults.

METHODS

We analyzed 4767 participants out of 4813 adults with diabetes enrolled from seven communities in a cross-sectional survey. Participants underwent several medical examinations, including the measurement of anthropometric factors, blood pressure, SUA, glucose, lipid profiles, urine albumin/creatinine ratio (ACR) and fundus photographs.

RESULTS

Compared with the first SUA tertile, the third tertile increased the prevalence of CVD by 22% (OR 1.22; 95% CI 1.01, 1.46) (P for trend <0.05) and increased the prevalence of DKD by 59% (OR 1.59; 95% CI 1.28, 1.97) for KDOQI definition. Compared with the first tertile, the OR (95% CI) of the number of diabetic complications, ranging from 0 to 2, associated with SUA level in ordinal logistic regression was 1.75 (1.44, 2.12) for the third tertile (P for trend <0.01). These associations were all fully adjusted. No association was found between the prevalence of DR and the SUA level.

CONCLUSIONS

A higher SUA level was associated with an increased prevalence of CVD and DKD and a variety of diabetic complications, other than DR, in men and postmenopausal women with T2DM. However, the causation remains to be demonstrated.

Uric Acid Contributes to Obesity-Paradox of the Outcome of Ischemic Stroke

Background: The mechanism of obesity paradox in stroke is not clear. This study aimed to investigate whether uric acid (UA) contributes to obesity-stroke outcome paradox.

Material and Methods: The study cohort consisted of 1,984 IS patients recruited in the ACROSS-China study. Serum UA and BMI were measured at admission. Low and high BMI groups were defined by the threshold of 24, and low and high UA by the age- and sex-specific median. Poor outcomes were defined as modified Rankin scale score ≥3 in 1 year after onset.

Results: UA was significantly and positively correlated with BMI. Lower levels of UA and BMI were significantly associated with higher risk of poor outcomes. Incidence of the poor outcome was 34.5, 29.4, 27.7, and 23.5% in the BMI/UA groups of low/low, high/low, low/high and high/high, respectively, with p = 0.001 for trend. The association between low UA and poor outcome was significant in lower BMI groups (odds ratio = 1.36, p = 0.006 in quartile 1 and 1.28, p = 0.021 in quartile 2), but the odds ratios were not significant in the BMI quartile 3 and 4 groups, with p = 0.038 for trend. The adverse effect of lower UA was significant in males, but not in females, with p = 0.006 for sex difference.

Conclusions: These findings suggest that low UA and low BMI have a joint effect on poor outcomes in IS patients. Across BMI categories, uric acid is differentially associated with functional outcome after stroke. This effect of low UA in the low BMI groups may be one of the mechanisms underlying the obesity-stroke paradox of the outcome in IS patients.

Uric acid therapy for vasculoprotection in acute ischemic stroke

Uric acid (UA) is a product of the catabolism of purine nucleotides, the principal constituents of DNA, RNA, and cellular energy stores, such as adenosine triphosphate. The main properties of UA include scavenging of hydroxyl radicals, superoxide anion, hydrogen peroxide, and peroxynitrite that make this compound to be the most potent antioxidant in the human plasma. As the result of two silencing mutations in the gene of the hepatic enzyme uricase which degrades UA to allantoin, humans have higher levels of UA than most mammals. However, these levels rapidly decrease following an acute ischemic stroke (AIS), and this decrement has been associated to worse stroke outcomes. This review highlights the safety and potential clinical value of UA therapy in AIS, particularly in patients more exposed to redox-mediated mechanism following the onset of ischemia, such as women, hyperglycemic patients, or patients treated with mechanical thrombectomy. The clinical findings are supported by preclinical data gathered in different laboratories, and in assorted animal species which include male and female individuals or animals harboring comorbidities frequently encountered in patients with AIS, such as hyperglycemia or hypertension. A remarkable finding in these studies is that UA targets its main effects in the brain vasculature since available evidence suggests that does not seem to cross the blood–brain barrier. Altogether, the available data with UA therapy extend the importance of vasculoprotection for effective neuroprotection at the bedside and reinforce the role of endothelial cells after brain ischemia for an increased survival of the whole neurovascular unit.

Biomarker for Ischemic Stroke Using Metabolome: A Clinician Perspective

Finding ischemic stroke biomarker is highly desirable because it can improve diagnosis even before a patient arrives to the hospital. Metabolome is one of new technologies that help to find biomarkers. Most metabolome-related ischemic stroke studies were done in Asia and had exploratory designs. Although failed to find specific biomarkers, they discovered several important metabolite-stroke associations which belong to three pathophysiological mechanisms: Excitotoxicity with activation of glutamate, resulting in the increase of glutamate derivatives proline and pyroglutamate; Oxidative stress with production of free radicals and perturbed concentrations of uric acid, matrix metalloproteinase-9, branch-chained amino acids, sphingolipids, homocysteine, asymmetric dimethylarginine, nitric oxide and folate cycle metabolites; and Stroke mediated inflammation, affecting phospholipid metabolism with perturbed levels of lysophosphatidylethanolamine and lysophosphatidylcholine. The discovered metabolite-stroke associations need further evaluation in prospective, high-quality studies with patients matched for age, risk factors, and medications.

Cypin: A novel target for traumatic brain injury

Cytosolic PSD-95 interactor (cypin), the primary guanine deaminase in the brain, plays key roles in shaping neuronal circuits and regulating neuronal survival. Despite this pervasive role in neuronal function, the ability for cypin activity to affect recovery from acute brain injury is unknown. A key barrier in identifying the role of cypin in neurological recovery is the absence of pharmacological tools to manipulate cypin activity in vivo. Here, we use a small molecule screen to identify two activators and one inhibitor of cypin's guanine deaminase activity. The primary screen identified compounds that change the initial rate of guanine deamination using a colorimetric assay, and secondary screens included the ability of the compounds to protect neurons from NMDA-induced injury and NMDA-induced decreases in frequency and amplitude of miniature excitatory postsynaptic currents. Hippocampal neurons pretreated with activators preserved electrophysiological function and survival after NMDA-induced injury in vitro, while pretreatment with the inhibitor did not. The effects of the activators were abolished when cypin was knocked down. Administering either cypin activator directly into the brain one hour after traumatic brain injury significantly reduced fear conditioning deficits 5 days after injury, while delivering the cypin inhibitor did not improve outcome after TBI. Together, these data demonstrate that cypin activation is a novel approach for improving outcome after TBI and may provide a new pathway for reducing the deficits associated with TBI in patients.

The Prognostic Value of Serum Uric Acid in the Acute Phase of Ischemic Stroke in Black Africans

BACKGROUND

The association between hyperuricemia and stroke outcome still remains controversial worldwide. This study aims to determine the prevalence of hyperuricemia and its association with the outcome of patients with acute ischemic stroke in a tertiary care hospital.

METHODS

This was a hospital-based prospective cohort study that included patients with ischemic stroke with baseline uric acid levels and 3-month post-stroke follow-up data. Associations between hyperuricemia and stroke outcomes were analyzed using multiple logistic regression, Kaplan-Meier, and Cox proportional hazards regression analysis.

RESULTS

A total of 480 patients were reviewed with a mean age of 62.8 ± 13.3 years. The prevalence of hyperuricemia was 52.3% with mean uricemia of 71.1 ± 25.3 mg/dL. There was a significant association between hyperuricemia and mortality with unadjusted odds ratio (OR) = 4.120 [95% (confidence interval [CI]: 2.466-7.153); P = .001)], but on multivariate analysis, hyperuricemia was not an independent predictor of stroke mortality [OR = 1.270 (CI: .547-2.946); P = .578)]. An independent association between increasing uric acid levels and mortality was noted on Cox proportional hazards regression; adjusted hazard ratio (95% CI) of 3.395 (2.114-5.452), P value greater than .001. Stroke mortality significantly increased across higher uric acid quintiles in patients with acute stroke (P < .001). Hyperuricemia was an independent predictor of poor functional outcome within 3 months after stroke with adjusted OR (95% CI) of 2.820 (1.359-5.851); P = .005.

CONCLUSIONS

Half of black African patients with ischemic stroke present with hyperuricemia, and hyperuricemia is a predictor of mortality and adverse functional outcomes. Further studies are therefore warranted to determine whether reducing hyperuricemia after stroke would be beneficial within our setting.

Lower serum uric acid level strongly predict short-term poor functional outcome in acute stroke with normoglycaemia: a cohort study in China

BACKGROUND

Conflicting results on the correlation between hyperuricemia and the prognosis of stroke had been reported and the close association between serum uric acid (SUA) and abnormal glycomatabolism might further complicate the assessment of the correlation. We aimed to investigate SUA in predicting the prognosis of acute stroke in different glycometabolism status.

METHODS

A total of 2907 patients aged from 18 to 85 (1220 diabetes mellitus (DM), 777 prediabetes and 910 normoglycemia) were selected from the Abnormal Glucose Regulation in Patients with Acute Stroke across China (ACROSS-China) study. The patients were divided into groups according to the SUA quartile as well as decile. The correlations between SUA and the poor outcome (mRS > 2) at discharge were assessed stratified by glucose metabolism status. Multivariate logistic regression was used to analyze the potential risk factors of poor in-hospital outcome of stroke and the risk-adjustment of the correlation between SUA and the prognosis of stroke. P < 0.05 was considered statistically significant.

RESULTS

SUA were divided first as Quartile1 to 4 (Quartile1 < 221 μmol L-1; Quartile2 (221-286) μmol L-1; Quartile3 (286-352) μmol L-1 and Quartile4 > 352 μmol L-1), then as decile1 to 10. In normoglycaemia, SUA quartiles, deciles and continuous SUA concentration were independently significantly associated with poor outcome. Q1 was independently associated with the higher possibility of poor functional outcome (compared to Q4, odds ratios (ORs) with 95% confidential interval (CI) was 3.79 (1.23-8.67) in Q1); Lower level of SUA in DM was also associated with poor functional outcome at discharge compared to the highest level of SUA(Q4)(OR with 95% CI, 2.07 (1.05-4.08)), however, lower SUA level was also related to severer stroke at admission in DM as well as in prediabetes (P < 0.001 in DM and 0.023 in prediabetes) and severer stroke resulted in worse functional outcome at discharge (OR with 95% CI, 12.15 (8.08-18.21) in DM and 11.58 (7.50-23.25) in prediabetes). But in normoglycamic stroke, SUA levels did not differ in stroke severity at admission (P = 0.066).

CONCLUSIONS

Low SUA level (<221 μmol L-1) independently and strongly predicts the short-term poor functional outcome in acute stroke with normoglycaemia other than diabetes or prediabetes.

Serum Uric Acid Is Associated with Poor Outcome in Black Africans in the Acute Phase of Stroke

BACKGROUND

Prognostic significance of serum uric acid (SUA) in acute stroke still remains controversial.

OBJECTIVES

To determine the prevalence of hyperuricemia and its association with outcome of stroke patients in the Douala General Hospital (DGH).

METHODS

This was a hospital based prospective cohort study which included acute stroke patients with baseline SUA levels and 3-month poststroke follow-up data. Associations between high SUA levels and stroke outcomes were analyzed using multiple logistic regression and survival analysis (Cox regression and Kaplan-Meier).

RESULTS

A total of 701 acute stroke patients were included and the prevalence of hyperuricemia was 46.6% with a mean SUA level of 68.625 ± 24 mg/l. Elevated SUA after stroke was associated with death (OR = 2.067; 95% CI: 1.449-2.950; p < 0.001) but did not predict this issue. However, an independent association between increasing SUA concentration and mortality was noted in a Cox proportional hazards regression model (adjusted HR = 1.740; 95% CI: 1.305-2.320; p < 0.001). Furthermore, hyperuricemia was an independent predictor of poor functional outcome within 3 months after stroke (OR = 2.482; 95% CI: 1.399-4.404; p = 0.002).

CONCLUSION

The prevalence of hyperuricemia in black African stroke patients is quite high and still remains a predictor of poor outcome.

Uric Acid Therapy Prevents Early Ischemic Stroke Progression

Background and Purpose—

Identification of neuroprotective therapies in acute ischemic stroke is imperative. We report a predefined analysis of the URICO-ICTUS trial (Efficacy Study of Combined Treatment With Uric Acid and r-tPA in Acute Ischemic Stroke) assessing the efficacy of uric acid (UA) compared with placebo to prevent early ischemic worsening (EIW) and the relevance of collateral circulation.

Methods—

URICO-ICTUS was a double-blind, placebo-controlled, phase 2b trial where a total of 411 patients treated with alteplase within 4.5 hours of stroke onset were randomized (1:1) to receive UA 1000 mg (n=211) or placebo (n=200) before the end of alteplase infusion. EIW defined an increment ≥4 points in the National Institutes of Health Stroke Scale score within 72 hours of treatment in the absence of hemorrhage or recurrent stroke. Logistic regression models assessed the interaction between therapy and the collateral circulation in 112 patients who had a pretreatment computed tomographic angiography.

Results—

EIW occurred in 2 of 149 (1%) patients with good outcome and 23 of 262 (9%) patients with poor outcome (χ 2 ; P =0.002). EIW occurred in 7 of 204 (3%) patients treated with UA and in 18 of 200 (9%) patients treated with placebo (χ 2 ; P =0.01). There was a significant interaction between the efficacy of UA to prevent EIW and collaterals ( P =0.029), with lower incidence in patients with good collaterals treated with UA compared with placebo (2% versus 15%, respectively; P =0.048).

Conclusions—

UA therapy may prevent EIW after acute stroke in thrombolysed patients. Optimal access of UA to its molecular targets through appropriate collaterals may modify the magnitude of the neuroprotective effect.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00860366.

Administration of Uric Acid in the Emergency Treatment of Acute Ischemic Stroke

Oxidative stress is one of the main mechanisms implicated in the pathophysiology of inflammatory and neurodegenerative diseases of the central nervous system (CNS). Uric acid (UA) is the end product of purine catabolism in humans, and it is the main endogenous antioxidant in blood. Low circulating UA levels have been associated with an increased prevalence and worse clinical course of several neurodegenerative and inflammatory diseases of the CNS, including Parkinson's disease and multiple sclerosis. Moreover, the exogenous administration of UA exerts robust neuroprotective properties in experimental models of CNS disease, including brain ischemia, spinal cord injury, meningitis, and experimental allergic encephalitis. In experimental brain ischemia, exogenous UA and the thrombolytic agent alteplase exert additive neuroprotective effects when administered in combination. UA is rapidly consumed following acute ischemic stroke, and higher UA levels at stroke admission are associated with a better outcome and reduced infarct growth at follow-up. A recent phase II trial demonstrated that the combined intravenous administration of UA and alteplase is safe and prevents an early decrease of circulating UA levels in acute ischemic stroke patients. Moreover, UA prevents the increase in the circulating levels of the lipid peroxidation marker malondialdehyde and of active matrix metalloproteinase (MMP) 9, a marker of blood-brain barrier disruption. The moderately sized URICOICTUS phase 2b trial showed that the addition of UA to thrombolytic therapy resulted in a 6% absolute increase in the rate of excellent outcome at 90 days compared to placebo. The trial also showed that UA administration resulted in a significant increment of excellent outcome in patients with pretreatment hyperglycemia, in females and in patients with moderate strokes. Overall, the encouraging neuroprotective effects of UA therapy in acute ischemic stroke warrants further investigation in adequately powered clinical trials.

Metabolomics reveals positive acceleration(+Gz)-induced metabolic perturbations and the protective effect of Ginkgo biloba extract in a rat model based on ultra high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

Positive acceleration (+Gz) in the head-to-foot direction generated by modern high-performance fighter jets during flight maneuvers is characterized by high G values and a rapid rate of acceleration, and is often long in duration and a repeated occurrence. The acceleration overload far exceeds the pilot's physiological tolerance limits and causes considerable strain on several organ systems. Despite the importance of monitoring pathophysiological alterations related to +Gz exposure, we lack a complete explanation of the pathophysiology of +Gz exposure. Ginkgo biloba extract (GBE) is a classic traditional Chinese medicine (TCM) that might exert a protective effect against +Gz exposure. However, its mechanism remains unclear. Here, a metabolomics approach based on ultra high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOFMS) was used to characterize +Gz-induced metabolic fluctuations in a rat model and to evaluate the protective effect of GBE. Using partial least-squares discriminant analysis for the classification and selection of biomarkers, eighteen serum metabolites related to +Gz exposure were identified, and were found to primarily involve the fatty acid β-oxidation pathway, glycerophospholipid metabolism, phospholipid metabolism, bile acid metabolism, purine metabolism and lysine metabolism. Taking these potential biomarkers as screening indexes, we found that GBE could reverse the pathological process of +Gz exposure by partially regulating the perturbed fatty acid β-oxidation pathway, glycerophospholipid metabolism, purine metabolism and lysine metabolism. This indicates that UHPLC-Q-TOFMS-based metabolomics provides a powerful tool to reveal serum metabolic fluctuations in response to +Gz exposure and to study the mechanism underlying TCM.

Uric Acid Therapy Improves Clinical Outcome in Women With Acute Ischemic Stroke

BACKGROUND AND PURPOSE

It is unknown whether women and men with acute ischemic stroke respond similar to an antioxidant regimen administered in combination with thrombolysis. Here, we investigated the independent effect of sex on the response to uric acid (UA) therapy in patients with acute stroke treated with alteplase.

METHODS

In the Efficacy Study of Combined Treatment With Uric Acid and rtPA in Acute Ischemic Stroke (URICO-ICTUS) trial, 206 women and 205 men were randomized to UA 1000 mg or placebo. In this reanalysis of the trial, the primary outcome was the rate of excellent outcome at 90 days (modified Rankin Scale, 0-1, or 2, if premorbid score of 2) in women and men using regression models adjusted for confounders associated with sex. The interaction of UA levels by treatment on infarct growth was assessed in selected patients.

RESULTS

Excellent outcome occurred in 47 of 111 (42%) women treated with UA, and 28 of 95 (29%) treated with placebo, and in 36 of 100 (36%) men treated with UA and 38 of 105 (34%) treated with placebo. Treatment and sex interacted significantly with excellent outcome (P=0.045). Thus, UA therapy doubled the effect of placebo to attain an excellent outcome in women (odd ratio [95% confidence interval], 2.088 [1.050-4.150]; P=0.036), but not in men (odd ratio [95% confidence interval], 0.999 [0.516-1.934]; P=0.997). The interactions between treatment and serum UA levels (P<0.001) or allantoin/UA ratio (P<0.001) on infarct growth were significant only in women.

CONCLUSIONS

In women with acute ischemic stroke treated with alteplase, the administration of UA reduced infarct growth in selected patients and was better than placebo to reach excellent outcome.

CLINICAL TRIAL REGISTRATION

URL: https://clinicaltrials.gov. Unique identifier: NCT00860366.

Uric acid improves glucose-driven oxidative stress in human ischemic stroke

OBJECTIVE

A study was undertaken to test in a subgroup reanalysis of the URICO-ICTUS trial whether uric acid is superior to placebo in improving the functional outcome in patients with acute stroke and hyperglycemia.

METHODS

Patients were part of the URICO-ICTUS trial, a double-blind study that compared the administration of uric acid versus placebo in stroke patients treated with alteplase within 4.5 hours of onset. The effect of therapy on the rate of excellent outcome at 90 days (modified Rankin Scale ≤ 2) in each tertile of admission glucose was assessed with multivariate adjusted models in 409 of the 421 randomized patients who had available pretreatment glucose levels. The effect of therapy on infarct growth was assessed in 72 patients who had longitudinal multimodal brain imaging.

RESULTS

Uric acid was associated with an increased rate of excellent outcome in patients with glucose levels in the upper tertile range (odds ratio [OR] = 2.9, 95% confidence interval [CI] = 1.0-8.3). However, the effect was not apparent for patients in the middle tertile (OR = 1.6, 95% CI = 0.8-3.6) or lower tertile of glucose (OR = 1.1, 95% CI = 0.5-2.6). Uric acid therapy was more effective than placebo in limiting infarct growth in the upper tertile range (Mann-Whitney U test, p = 0.04) but not in the middle tertile (p = 0.95) or lower tertile of glucose (p = 0.30). Uric acid also proved superior to placebo in reducing infarct growth in patients with early recanalization.

INTERPRETATION

Uric acid therapy was associated with reduced infarct growth and improved outcome in patients with hyperglycemia during acute stroke.

Middle cerebral artery remodeling following transient brain ischemia is linked to early postischemic hyperemia: a target of uric acid treatment

Ischemia impairs blood supply to the brain, and reperfusion is important to restore cerebral blood flow (CBF) and rescue neurons from cell death. However, reperfusion can induce CBF values exceeding the basal values before ischemia. This hyperemic effect has been associated with a worse ischemic brain damage, albeit the mechanisms that contribute to infarct expansion are not clear. In this study, we investigated the influence of early postischemic hyperemia on brain damage and middle cerebral artery (MCA) properties and the effect of treatment with the endogenous antioxidant uric acid (UA). The MCA was occluded for 90 min followed by 24 h reperfusion in adult male Sprague-Dawley rats. Cortical CBF increases at reperfusion beyond 20% of basal values were taken as indicative of hyperemia. UA (16 mg/kg) or vehicle (Locke's buffer) was administered intravenously 135 min after MCA occlusion. Hyperemic compared with nonhyperemic rats showed MCA wall thickening (sham: 22.4 ± 0.8 μm; nonhyperemic: 23.1 ± 1.2 μm; hyperemic: 27.8 ± 0.9 at 60 mmHg; P < 0.001, hyperemic vs. sham) involving adventitial cell proliferation, increased oxidative stress, and interleukin-18, and more severe brain damage. Thus MCA remodeling after ischemia-reperfusion takes place under vascular oxidative and inflammatory stress conditions linked to hyperemia. UA administration attenuated MCA wall thickening, induced passive lumen expansion, and reduced brain damage in hyperemic rats, although it did not increase brain UA concentration. We conclude that hyperemia at reperfusion following brain ischemia induces vascular damage that can be attenuated by administration of the endogenous antioxidant UA.

Potential of serum metabolites for diagnosing post-stroke cognitive impairment

A panel of serum metabolite markers (glutamine, kynurenine, and LysoPC(18:2)) was identified as candidate diagnostic biomarkers for post-stroke cognitive impairment.

Edaravone's free radical scavenging mechanisms of neuroprotection against cerebral ischemia: review of the literature

Free radicals and oxidative stress play key roles in cerebral ischemic pathogenesis and represent pharmacological targets for treatment. Edaravone (Edv), one of antioxidant agents that have been used in acute ischemic stroke in both clinical settings and animal experiments, exerts neuroprotective effect on ischemic injured brains. This review is aimed to elaborate the latest molecular mechanisms of the neuroprotection of Edv on cerebral ischemia and provide reasonable evidence in its clinical application. It is found that Edv has neuroprotective influence on cerebral ischemia, which is closely related to the facets of scavenging reactive oxygen species (ROS), hydroxyl radical (ċOH) and reactive nitrogen species (RNS). And it is a good antioxidant agent that can be safely used in the treatment of cerebral ischemia and chronic neurodegenerative disorders as well as other ischemia/reperfusion (I/R)-related diseases. The combination of Edv with thrombolytic therapy also can be applied in clinical settings and will be greatly beneficial to patients with stroke.

Serum uric acid level is associated with the prevalence but not with survival of amyotrophic lateral sclerosis in a Chinese population

Oxidative stress is involved in the pathogenesis of amyotrophic lateral sclerosis (ALS). Serum uric acid (UA) has anti-oxidative effect. To clarify the associations between UA and sporadic ALS (SALS) in Chinese population. A total of 512 SALS patients and 501 age- and gender- matched healthy controls were included, with fasting serum UA evaluated. The ALS functional rating scale-Revised was used to assess disease severity, and the mean change of ALSFRS-R per month (△ALS-FRS-R/m) to assess its progression. Four hundred forty-five patients were followed up. Survival and progression were estimated according to quartiles and gender-specific quartiles of UA. The mean age of SALS patients was 53.3 ± 11.7 years. UA level of SALS was significantly lower than controls (p = 0.001). Male SALS had higher UA than female (p = 0.001). The occurrence of SALS was increased in the lowest, second and third quartiles compared with the highest quartile (p = 0.001). In the gender-specific analysis, increased occurrence was found in the lowest and second quartiles compared with third and fourth quartiles in both males and females SALS (p(f) = 0.001 and p(m) < 0.05). No correlation was found between △ALS-FRS-R/m and UA (p > 0.05), nor between SALS survival and UA. SALS patients have low level of serum UA than controls. Low level of uric acid may be associated with increased occurrence of SALS in Chinese population. Uric acid level may not contribute to the survival or progression of SALS.

Allopurinol as a preventive contrivance after acute ischemic stroke in patients with a high level of serum uric acid: a randomized, controlled trial

OBJECTIVES

To assess the clinical relevance (functional outcome) of a 3-month allopurinol regimen in patients with high serum uric acid (SUA) levels and acute ischemic stroke without considering the changes in SUA levels.

MATERIALS AND METHODS

In a randomized, double-blind, controlled study, 70 patients (45 females, 25 males) with acute ischemic stroke who had elevated levels of SUA were included. They were divided in two 35-patient groups to investigate the effect of 3 months of an allopurinol (200 mg/day) regimen versus placebo on their functional outcome, which was evaluated using a modified Rankin scale.

RESULTS

The overall mean age was 68.9 ± 11.33 years (range 27-89). The final favorable functional status (mRS = 0-2) was 23 (65.7%) and 14 (40.0%) in the treated and placebo groups, respectively, which was strongly associated with allopurinol consumption (OR = 4.646, p = 0.014) and age ≤70 years (OR = 0.139, p = 0.005) in patients with ischemic stroke after adjusting for confounders. There was no significant difference in death between allopurinol-treated cases (3; 8.6%) and placebo-treated ones (6; 17.2%; p = 0.278).

CONCLUSION

Allopurinol treatment was well tolerated and improved the 3-month functional status of patients with acute ischemic stroke who had high levels of SUA without considering the decreasing effect of allopurinol on SUA.

Effects of uric acid levels on outcome in severe ischemic stroke patients treated with intravenous recombinant tissue plasminogen activator

Uric acid (UA) has been known to be a neuroprotective antioxidant because of its free radical scavenger activity. We studied the influence of UA in patients with acute ischemic stroke after thrombolytic therapy. Two hundred eighteen consecutive patients treated with intravenous thrombolysis were included in this analysis. We analyzed the relationship between serum UA levels obtained at the emergency department and clinical outcomes. Early improvement and excellent functional outcomes were measured using the National Institutes of Health Stroke Scale (NIHSS) 24 h after onset and the modified Rankin scale after 3 months. There was no significant relationship between serum UA levels and early improvement or excellent functional outcome in the total patients (p = 0.583 and p = 0.082, respectively). However, in patients with severe baseline stroke deficits (NIHSS score ≥15), higher-tertile UA levels were significantly associated with excellent functional outcomes (p = 0.003). Excellent functional outcomes in patients with severe baseline disability might have a significant association with serum UA levels particularly in men but not in women (p = 0.007 in men and p = 0.621 in women). Increased serum UA levels might be associated with better outcomes in ischemic stroke patients treated with intravenous thrombolysis, but the effectiveness of UA can differ by initial stroke severity and gender.

Uric acid is associated with the prevalence but not disease progression of multiple system atrophy in Chinese population

Oxidative stress is involved in the pathogenesis of multiple system atrophy (MSA). Uric acid has an antioxidative effect. Our aim is to clarify the correlations between serum uric acid and MSA in Chinese population. A total of 234 patients with probable MSA and 240 age- and gender- matched healthy controls were included in the study. The serum uric acid levels of all the patients and controls were evaluated. The Unified MSA Rating Scale (UMSARS) was used to assess the severity and the mean rate of annualized changes of UMSARS to assess the progression of MSA. The mean age of MSA patients was 58.90 ± 9.00 years and the mean disease duration was 2.60 ± 1.75 years. The serum uric acid levels of MSA patients were significantly lower than that of controls in males (p = 0.0001). The occurrence of MSA was increased in the lowest uric acid quartiles compared with the highest uric acid quartiles (p = 0.005). In a gender-specific analysis, increased occurrence was found in the lowest quartiles and second quartiles compared with the highest quartiles in males (p = 0.001 and p = 0.0001 respectively), but not in females. No correlation was found between the mean rate of annualized changes and serum levels of uric acid, as well as other independent factors, such as age, BMI, gender, subtype (C-type or P-type) and disease duration at the initial visit in 107 followed-up patients. MSA patients have lower levels of serum uric acid than controls. High levels of serum uric acid may be associated with a lower prevalence of MSA in the Chinese population, especially in males. However, serum uric acid does not deteriorate or ameliorate the progression of MSA.

Nutrition assessment and management in amyotrophic lateral sclerosis

In recent years nutrition assessment and management in amyotrophic lateral sclerosis (ALS) have drawn increased attention. Frequent evaluation of nutrition status is warranted in ALS, given the common occurrence of dysphagia and hypermetabolism and varying disease progression rates. Nutrition management includes dietary and swallow strategies, possible gastrostomy tube placement, and recommendations for vitamin and mineral supplementation. Strategies to assess and optimize nutrition status and prolong survival in ALS patients are reviewed with recommendations based on current research.

Beyond gout: uric acid and cardiovascular diseases

OBJECTIVES

This article discusses the results of clinical and experimental studies that examine the association of hyperuricemia and gout with cardiovascular (CV) disease.

METHODS

Key papers for inclusion were identified by a PubMed search, and articles were selected for their relevance to the topic, according to the authors' judgment.

RESULTS AND CONCLUSIONS

Significant progress has been made in confirming an association, possibly causal, between hyperuricemia and CV outcomes. Xantine-oxidase (XO) inhibitors appear to be the most promising agents for prevention and treatment of CV consequences associated with hyperuricemia. Several small and medium sized studies have examined the effect of these agents on CV function in a variety of patient populations. Improvements in measures of endothelial function, oxidative stress, cardiac function, hemodynamics, and certain inflammatory indices have been demonstrated. Compounds for XO inhibition with more specific clinical effects and fewer side effects than allopurinol may be promising options to further explore the therapeutic potential in patients with CV disease. It is too early to make clinical recommendations with regard to the benefits of using XO inhibitor allopurinol or the novel febuxostat in patients with asymptomatic increased UA levels and high CV risk because only a small number of studies have shown that they may be beneficial in terms of CV outcomes. More studies are therefore needed to determine the potential of these drugs for reducing the risk of developing CV disease.

Serum uric acid levels and cerebral microbleeds in patients with acute ischemic stroke

Unlike experimental studies indicating a neuroprotective property of uric acid, clinical studies have shown that elevated levels of uric acid are associated with a risk of ischemic stroke. However, the association of uric acid with cerebral hemorrhage has seldom been tested. We aimed to elucidate the association between uric acid and cerebral microbleeds (CMBs), a hemorrhage-prone cerebral microangiopathy. Seven hundred twenty-four patients with ischemic stroke who were consecutively admitted to our hospital were included in this study. We collected demographic, clinical, and laboratory data, including uric acid level, and examined the presence of CMBs using T2*-weighted gradient-echo MRI. We used logistic regression analysis to examine an independent association between uric acid and CMBs. Two-hundred twenty-six patients had CMBs (31.2%). After adjusting for possible confounders, elevated uric acid was independently associated with the presence of CMBs (the highest quartile vs. lowest quartile, adjusted odd ratio [OR], 1.98; 95% confidence interval [CI], 1.16–3.39). This association retained in patients with deep or infratentorial CMBs (with or without lobar CMBs) but not among those with lobar CMBs. In addition, this association was robust among patients with hypertension (the highest quartile vs. lowest quartile, adjusted OR, 2.74; 95% CI, 1.43–5.24). In contrast, we did not find the association in patients without hypertension. We demonstrated that serum uric acid is independently associated with the presence of CMBs. In particular, the relation between uric acid and CMBs was robust in hypertensive patients.

Effect of chronic glutathione deficiency on the behavioral phenotype of Gclm-/- knockout mice

Enhanced oxidative stress or deficient oxidative stress response in the brain is associated with neurodegenerative disorders and behavioral abnormalities. Previously we generated a knockout mouse line lacking the gene encoding glutamate-cysteine ligase modifier subunit (GCLM). Gclm(-/-) knockout (KO) mice are viable and fertile, yet exhibit only 9-35% of wild-type levels of reduced glutathione (GSH) in tissues, making them a useful model for chronic GSH depletion. Having the global absence of this gene, KO mice--from the time of conception and throughout postnatal life--experience chronic oxidative stress in all tissues, including brain. Between postnatal day (P) 60 and P100, we carried out behavioral phenotyping tests in adults, comparing male and female Gclm(-/-) with Gclm(-/-) wild-type (WT) littermates. Compared with WT, KO mice exhibited: subnormal anxiety in the elevated zero maze; normal overall exploratory open-field activity, but slightly more activity in the peripheral zones; normal acoustic startle and prepulse inhibition reactions; normal novel object recognition with increased time attending to the stimulus objects; slightly reduced latencies to reach a random marked platform in the Morris water maze; normal spatial learning and memory in multiple phases of the Morris water maze; and significantly greater hyperactivity in response to methamphetamine in the open field. These findings are generally in agreement with two prior studies on these mice and suggest that the brain is remarkably resilient to lowered GSH levels, implying significant reserve capacity to regulate reactive oxygen species-but with regional differences such that anxiety and stimulated locomotor control brain regions might be more vulnerable.

Effect of vitamin C deficiency during postnatal development on adult behavior: functional phenotype of Gulo-/- knockout mice

Organisms using oxygen for aerobic respiration require antioxidants to balance the production of reactive oxygen species during metabolic processes. Various species--including humans and other primates--suffer mutations in the GULO gene encoding L-gulono-γ-lactone oxidase; GULO is the rate-limiting enzyme in the biosynthesis of ascorbate, an important cellular antioxidant. Animals lacking the ability to synthesize vitamin C develop scurvy without dietary supplementation. The Gulo-/- knockout (KO) mouse requires oral supplemental vitamin C; without this supplementation the animal dies with a scorbutic condition within several weeks. Vitamin C is known to be most abundant in the brain, where it is believed to play important roles in neuroprotection, neurotransmission and neuromodulation. We therefore hypothesized that ascorbate deficiency in Gulo-/- KO mice might lead to an abnormal behavioral phenotype. We established the amount of ascorbate in the drinking water (220 ppm) necessary for generating a chronic low-ascorbate status in the brain, yet clinically the mice appeared healthy throughout 100 days postpartum at which time all behavioral-phenotyping tests were completed. Compared with Gulo+/+ wild-type littermates, ascorbate-deficient Gulo-/- mice were found to be less active in moving in their environment; when in water, these mice swam more slowly in some tests, consistent with a mild motor deficit. We found no evidence of cognitive, anxiety or sensorimotor-gating problems. Despite being less active, Gulo-/- mice exhibited exaggerated hyperactivity to the dopaminergic agonist methamphetamine. The subnormal movement, combined with hypersensitivity to a dopamine agonist, point to developmental ascorbate deficiency causing long-term striatal dysfunction.

Uric acid as one of the important factors in multifactorial disorders--facts and controversies

With considering serum concentration of the uric acid in humans we are observing hyperuricemia and possible gout development. Many epidemiological studies have shown the relationship between the uric acid and different disorders such are obesity, metabolic syndrome, hypertension and coronary artery disease. Clinicians and investigators recognized serum uric acid concentration as very important diagnostic and prognostic factor of many multifactorial disorders. This review presented few clinical conditions which are not directly related to uric acid, but the concentrations of uric acid might have a great impact in observing, monitoring, prognosis and therapy of such disorders. Uric acid is recognized as a marker of oxidative stress. Production of the uric acid includes enzyme xanthine oxidase which is involved in producing of radical-oxigen species (ROS). As by-products ROS have a significant role in the increased vascular oxidative stress and might be involved in atherogenesis. Uric acid may inhibit endothelial function by inhibition of nitric oxide-function under conditions of oxidative stress. Down regulation of nitric oxide and induction of endothelial dysfunction might also be involved in pathogenesis of hypertension. The most important and well evidenced is possible predictive role of uric acid in predicting short-term outcome (mortality) in acute myocardial infarction (AMI) patients and stroke. Nephrolithiasis of uric acid origin is significantly more common among patients with the metabolic syndrome and obesity. On contrary to this, uric acid also acts is an “antioxidant”, a free radical scavenger and a chelator of transitional metal ions which are converted to poorly reactive forms.

Uric acid levels predict survival in men with amyotrophic lateral sclerosis

Elevated uric acid levels have recently been found to be associated with slower disease progression in Parkinson's disease, Huntington's disease, multiple system atrophy, and mild cognitive impairment. The aim of this study is to determine whether serum uric acid levels predict survival in amyotrophic lateral sclerosis (ALS). A total of 251 people with ALS enrolled in two multicenter clinical trials were included in our analysis. The main outcome measure was survival time, which was calculated as time to death, tracheostomy, or permanent assistive ventilation, with any event considered a survival endpoint. Cox proportional hazards models were used to estimate the hazard ratio (HR) of reaching a survival endpoint according to baseline uric acid levels after adjusting for markers of disease severity (FVC, total ALSFRS-R score, time since symptom onset, diagnostic delay, BMI, bulbar vs. spinal onset, age, and riluzole use). There was a dose-dependent survival advantage in men, but not women, with higher baseline uric acid levels (logrank test: p = 0.018 for men, p = 0.81 for women). There was a 39% reduction in risk of death during the study for men with each 1 mg/dl increase in uric acid levels (adjusted HR: 0.61, 95% CI 0.39-0.96, p = 0.03). This is the first study to demonstrate that serum uric acid is associated with prolonged survival in ALS, after adjusting for markers of disease severity. Similar to previous reports in Parkinson's disease, this association was seen in male subjects only.

Relationship between serum uric acid and cerebral white matter lesions in the elderly

BACKGROUND AND AIMS

Recent evidence suggests that hyperuricemia might increase the risk of cardiovascular disease. Cardiovascular risk factors are well recognized to be associated with cerebral white matter lesion (WML). We hypothesized that hyperuricemia is related to higher grade of WML in both men and women.

METHODS AND RESULTS

A total of 108 men and 123 women were enrolled from those who signed up for the annual Health Examination for the Elderly Program in Taipei from 2006 to 2008. Information in interview data, clinical and laboratory examinations were collected. Hyperuricemia was defined by uric acid ≥458.0 μmol/L in men and ≥392.6 μmol/L in women. Two types of WML including periventricular hyper-intensity (PVH) and deep white matter hyper-intensity (DWMH), ascertained by cranial magnetic resonance imaging, were graded. Association between hyperuricemia and high grade WML was evaluated by using multiple logistic regression analysis. The prevalences of hyperuricemia were 13.9% and 17.9% for men and women, respectively. The prevalences of moderate-to-severe PVH among men and women were 16.7% and 7.3%; while the prevalences of moderate-to-severe DWMH for men and women were 19.4% and 11.4%, respectively. Hyperuricemia was related to moderate-to-severe DWMH in men, after controlling for age, education years, smoking, alcohol consumption, metabolic Z score, silent infarct, and the use of anti-hypertensives, lipid-lowering and anti-diabetic agents, the association remained significant. The relationship was not evident among women. We did not find an association between hyperuricemia and PVH.

CONCLUSIONS

Hyperuricemia was positively associated with high grade DWMH in older men, but not in women.

Neuroinflammation and cerebrovascular disease in old age: a translational medicine perspective

The incidence of cerebrovascular disease is highest in the elderly population. However, the pathophysiological mechanisms of brain response to cerebral ischemia in old age are currently poorly understood. Ischemic changes in the commonly used young animal stroke models do not reflect the molecular changes associated with the aged brain. Neuroinflammation and oxidative stress are important pathogenic processes occurring during the acute phase of cerebral ischemia. Free radical generation is also implicated in the aging process, and the combination of these effects in elderly stroke patients could explain the higher risk of morbidity and mortality. A better understanding of stroke pathophysiology in the elderly patient would assist in the development of new therapeutic strategies for this vulnerable age group. With the increasing use of reperfusion therapies, inflammatory pathways and oxidative stress remain attractive therapeutic targets for the development of adjuvant neuroprotective agents. This paper will discuss these molecular aspects of acute stroke and senescence from a bench-to-bedside research perspective.

Translational Stroke Research of the Combination of Thrombolysis and Antioxidant Therapy

Stroke is an enormous public health problem with an imperative need for more effective therapy. Recombinant tissue plasminogen activator is the only licensed drug for acute stroke, but its efficacy may be limited by the toxicity of the compound and by reperfusion injury. The coadministration of neuroprotective drugs could augment the value of thrombolytic therapy, but the evidence in support of this approach is scarce. The use of the free radical trapping NXY-059, either with or without recombinant tissue plasminogen activator, was not successful in Phase III studies. However, these results could reflect its weak antioxidant capacity, poor blood–brain barrier penetration, and lack of synergism with recombinant tissue plasminogen activator as well as the overly broad treatment window used in the reported trials. This article contends that further translational research should explore newer antioxidant drugs in combination with thrombolytic agents, but only if the combination yields additive or synergistic effects in preclinical thromboembolic models or in biomarker-assisted Phase II studies. Edaravone and novel nitrones endowed with a better pharmacokinetic profile or multitarget and thrombolytic activity are discussed as well as the latest research data on uric acid, a strong endogenous antioxidant in blood that is early consumed after acute stroke. The coadministration of uric acid and recombinant tissue plasminogen activator has shown to provide synergistic neuroprotection in experimental thromboembolic models and to lessen several biomarkers of oxidative stress in patients with acute stroke. The clinical efficacy of uric acid is currently under investigation in a Phase III trial that follows current recommendations of also evaluating surrogate biomarkers of treatment effects.

Uric acid levels are relevant in patients with stroke treated with thrombolysis

BACKGROUND AND PURPOSE

Uric acid (UA) is a neuroprotective antioxidant that improves the benefits of alteplase in experimental ischemia. However, it is unknown whether endogenous UA also influences the response to thrombolysis in patients with stroke.

METHODS

A total of 317 consecutive patients treated with thrombolysis were included in a prospective stroke registry. Demographics, laboratory data, neurological course, and infarction volume were prospectively collected. Excellent outcome was defined as achieving a modified Rankin Scale score <2 at 90 days. Binary and ordinal logistic regression models were used to analyze modified Rankin Scale score at 90 days.

RESULTS

UA levels were significantly higher in patients with an excellent outcome than in patients with a poor outcome (5.82 [1.39] versus 5.42 [1.81], P=0.029). In multivariate models, increased UA levels (OR, 1.23; 95% CI, 1.03 to 1.49; P=0.025) were associated with an excellent outcome and with an increased risk of shifting to a better category across the modified Rankin Scale (OR, 1.19; 95% CI, 1.04 to 1.38; P=0.014) independently of the effect of confounders. The levels of UA and the volume of final infarction were inversely correlated (r=-0.216, P<0.001) and the inverse correlation remained after adjustment for age, sex, and baseline National Institutes of Health Stroke Scale score (t value=-2.54, P=0.01). Significantly lower UA levels were found in patients with malignant middle cerebral artery infarction and parenchymal hemorrhage post-thrombolysis.

CONCLUSIONS

Increased UA serum levels are associated with better outcome in patients with stroke treated with reperfusion therapies. These results support the assessment of the potential neuroprotective role of the exogenous administration of UA in patients with stroke treated with thrombolysis.

Oral bioavailability of ATP after prolonged administration

Purinergic receptors are important for the regulation of inflammation, muscle contraction, neurotransmission and nociception. Extracellular ATP and its metabolites are the main ligands for these receptors. Occasional reports on beneficial results of ATP administration in human and animal studies have suggested the bioavailability of oral ATP supplements. We investigated whether prolonged daily intake of oral ATP is indeed bioavailable. Thirty-two healthy subjects were randomised to receive 0, 250, 1250 or 5000 mg ATP per d for 28 d by means of enteric-coated pellets. In addition, on days 0 and 28, all thirty-two subjects received 5000 mg ATP to determine whether prolonged administration would induce adaptations in the bioavailability of ATP. ATP supplementation for 4 weeks did not lead to changes in blood or plasma ATP concentrations. Of all ATP metabolites, only plasma uric acid levels increased significantly after the administration of 5000 mg of ATP. Prolonged administration of ATP was safe as evidenced from liver and kidney parameters. We conclude that oral administration of ATP only resulted in increased uric acid concentrations. On the basis of these findings, we seriously question the claimed efficacy of oral ATP at dosages even lower than that used in the present study.

Decrease in uric acid in acute ischemic stroke correlates with stroke severity, evolution and outcome

BACKGROUND

Although uric acid (UA) is one of the most important antioxidants in plasma and appears to be neuroprotective in animal models, results from human studies are controversial. In this study, we investigated the kinetics of serum UA concentrations in the acute, subacute and chronic phase of ischemic stroke and its relation with initial stroke severity, stroke evolution in the subacute phase and long-term stroke outcome.

METHODS

Serum concentrations of UA were measured in 199 stroke patients at admission (median, 2.8 h after stroke onset), at 24 h, 72 h, day 7, month 1 and month 3 after onset of stroke. We evaluated the relationship between changes in UA concentrations and (a) stroke severity [patients with transient ischemic attack (TIA) vs. stroke patients, National Institutes of Health Stroke Scale (NIHSS) score at admission], (b) stroke evolution (stroke progression, infarct volume at 72 h), and (c) stroke outcome [modified Rankin scale (mRS) score at month 3, mortality].

RESULTS

UA concentrations decreased significantly during the first 7 days after stroke onset before returning to baseline (p < 0.001). Mean plasma UA concentrations decreased from 336.66 +/- 113.01 micromol/L at admission to 300.37 +/- 110.04 micromol/L at day 7 (p < 0.001) in patients with stroke, but did not change significantly in patients with TIA. Changes in UA concentrations from admission to day 7 (DeltaUA(day 7)) correlated with the NIHSS score (rho = 0.32; p < 0.001), stroke progression (rho = 0.29; p = 0.001), infarct volume (rho = 0.37; p < 0.001), mRS score (rho = 0.28; p = 0.001) and mortality (p = 0.010).

CONCLUSIONS

Decreases in UA during the first week after onset of stroke correlates with more severe stroke, unfavorable stroke evolution, and poor long-term stroke outcome.

Serum bilirubin and uric acid levels as the bad prognostic factors in the ischemic stroke

Bilirubin (Bil) and uric acid (UA) are the endogenous antioxidant compounds possibly involved in the pathogenesis of ischemic stroke (IS). Our goal was to find the relationship between serum Bil and UA levels with clinical presentation and outcomes of patients suffering from IS. Forty-three patients (mean age: 71.9 years, +/- 12.1; women: 48.8%) with confirmed IS were enrolled. Stroke severity was assessed by the National Institutes of Health Stroke Scale (NIHSS) after 1, 3, 5, and 10 days and functional disability was assessed three months after stroke onset using the Barthel Index (BI). Serum Bil and UA levels were measured 1, 3, 5, and 10 days after stroke. The difference between NIHSS scores from days 1 and 10 (improvement ratio) inversely correlated with the average UA serum level (r = -0.48, p < .01) but not with the average Bil level. Negative correlations were observed between the BI measured three months after stroke compared to the average Bil serum level (r = -0.5, p < .01). However, no relationship between BI and UA level was observed. Our results indicated that Bil and UA levels are poor prognostic factors for ischemic stroke.

Hypoxia inducible factor 1 as a therapeutic target in ischemic stroke

In stroke research, a significant focus is to develop therapeutic strategies that prevent neuronal death and improve recovery. Yet, few successful therapeutic strategies have emerged. Hypoxia-inducible factor 1 (HIF-1) is a key regulator in hypoxia. It has been suggested to be an important player in neurological outcomes following ischemic stroke due to the functions of its downstream genes. These include genes that promote glucose metabolism, angiogenesis, erythropoiesis, and cell survival. Many lines of evidence have shown that HIF-1 is induced in ischemic brains. Importantly, it seems that HIF-1 is primarily induced in the salvageable tissue of an ischemic brain, penumbra. However, the effect of HIF-1 on neuronal tissue injuries is still debatable based on evidence from in vitro and preclinical studies. Furthermore, it is of importance to understand the mechanism of HIF-1 degradation after its induction in ischemic brain. This review provides a present understanding of the mechanism of HIF-1 induction in ischemic neurons and the potential effect of HIF-1 on ischemic brain tissue. The author also elaborates on potential therapeutic approaches through understanding of the induction mechanism and of the potential role of HIF-1 in ischemic stroke.

Randomized clinical stroke trials in 2007

This article reviews the randomized control trials (RCT’s) that were published in 2007 of emerging pharmacotherapies in patients with acute (≤ 2 weeks), sub-acute (2 to 12 weeks) and chronic (≥ 12 weeks) stroke. A Medline search generated 22 RCT’s in stroke in the year 2007 in the English language. These trials were primarily efficacy studies. These included the role of statins (an anti-lipid agent) in reducing post-stroke morbidity and mortality, and decreasing the carotid atherosclerotic plaque in middle aged patients at increased risk of cardiovascular disease; glucose-potassium-insulin infusion in hyperglyceamic acute stroke patients; pioglitazone (an anti-diabetic medication) to reduce recurrence of stroke in Type 2 diabetic patients; administration of intra-arterial urokinase (a thrombolytic agent) and the role of laser therapy in clot dissolution given that at present there is only one FDA approved thrombolytic agent (r TPA); benefit of warfarin (an anticoagulant) in elderly patients with atrial fibrillation in the community; NXY (a free radical trapping agent) and minocycline both tested as neuroprotectants; and zoledronate (an intravenous bisphosphonate) to prevent loss of bone mineral density of the affected extremity, and finally the role of nicardipine (a Calcium channel blocker) in the prevention of vasospasm, and hydrocortisone to prevent hyponatraemia after sub-arachnoid hemorrhage. Finally the role of non-pharmacotherapy like stents for patient’s with internal carotid artery dissection with tandem internal carotid and middle cerebral artery occlusion and in vertebral artery stenosis.

Tissue plasminogen activator (tPA) and matrix metalloproteinases in the pathogenesis of stroke: therapeutic strategies

Today there exists only one FDA-approved treatment for ischemic stroke; i.e., the serine protease tissue-type plasminogen activator (tPA). In the aftermath of the failed stroke clinical trials with the nitrone spin trap/radical scavenger, NXY-059, a number of articles raised the question: are we doing the right thing? Is the animal research truly translational in identifying new agents for stroke treatment? This review summarizes the current state of affairs with plasminogen activators in thrombolytic therapy. In addition to therapeutic value, potential side effects of tPA also exist that aggravate stroke injury and offset the benefits provided by reperfusion of the occluded artery. Thus, combinational options (ultrasound alone or with microspheres/nanobubbles, mechanical dissociation of clot, activated protein C (APC), plasminogen activator inhibitor-1 (PAI-1), neuroserpin and CDP-choline) that could offset tPA toxic side effects and improve efficacy are also discussed here. Desmoteplase, a plasminogen activator derived from the saliva of Desmodus rotundus vampire bat, antagonizes vascular tPA-induced neurotoxicity by competitively binding to low-density lipoprotein related-receptors (LPR) at the blood-brain barrier (BBB) interface, minimizing the tPA uptake into brain parenchyma. tPA can also activate matrix metalloproteinases (MMPs), a family of endopeptidases comprised of 24 mammalian enzymes that primarily catalyze the turnover and degradation of the extracellular matrix (ECM). MMPs have been implicated in BBB breakdown and neuronal injury in the early times after stroke, but also contribute to vascular remodeling, angiogenesis, neurogenesis and axonal regeneration during the later repair phase after stroke. tPA, directly or by activation of MMP-9, could have beneficial effects on recovery after stroke by promoting neurovascular repair through vascular endothelial growth factor (VEGF). However, any treatment regimen directed at MMPs must consider their pleiotropic nature and the likelihood of either beneficial or detrimental effects that might depend on the timing of the treatment in relation to the stage of brain injury.