Prediction Factors of Recurrent Ischemic Events in One Year after Minor Stroke

Background

The risk of a subsequent stroke following a minor stroke is high. However, there are no effective rating scales to predict recurrent stroke following a minor one. Therefore, we assessed the risk factors associated with recurrent ischemic stroke or transient ischemic attack (TIA) within one year of minor stroke onset in order to identify possible risk factors.

Methods

Eight hundred and sixty-three non-cardioembolic ischemic stroke patients in the Chinese IntraCranial AtheroSclerosis Study that presented with minor stroke, defined as an admission National Institutes of Health stroke scale (NIHSS) score of ≤3, were consecutively enrolled in our study. Clinical information and imaging features upon admission, and any recurrent ischemic stroke or TIA within one year was recorded. Cox regression was used to identify risk factors associated with recurrent ischemic stroke or TIA within the year following stroke onset.

Results

A total of 50 patients (6.1%) experienced recurrent ischemic stroke or TIA within one year of minor stroke onset. Multivariate Cox regression model identified lower admission NIHSS score (HR, 1.75; 95% CI, 1.32 to 2.33; P<0.0001), history of coronary heart disease (HR, 2.62; 95% CI, 1.17 to 5.86; P = 0.02), severe stenosis or occlusion of large cerebral artery (HR, 4.68; 95% CI, 1.87 to 11.7; P = 0.001), and multiple acute cerebral infarcts (HR, 2.61; 95% CI, 1.01 to 6.80; P = 0.05) as independent risk factors for recurrent ischemic stroke or TIA within one year.

Conclusions

Some minor stroke patients are at higher risk for recurrent ischemic stroke or TIA. Urgent and intensified therapy may be reasonable in these patients.     

High Total Hospitalization Cost but Low Cost of Imaging Studies in Recurrent Acute Ischemic Stroke Patients

Background

Due to the high risk and severity of recurrence after stroke attack, recurrence is a major reason contributing to the disease burden. This study aims to determine whether recurrence is a significant contributor of hospitalization cost in items for ischemic stroke patients.

Methods

This study assessed acute ischemic stroke patients admitted to an academic medical center in 2003 through 2009. The t-test and Chi-square tests were used to compare first-ever and recurrent ischemic stroke groups in terms of total and categorized hospitalization cost, and multiple regression was performed to assess the influence of stroke recurrence.

Results

Recurrent ischemic strokes were associated with higher total cost, but examination cost showed no difference between the two groups. The recurrent stroke group showed higher laboratory but lower imaging cost. Of imaging studies, there was no significant difference in computed tomography scan cost while the first-ever stroke group spent more on magnetic resonance imaging and sonography. Controlling for other influential factors, recurrence was discovered to be a significant factor in lowering examination cost.

Conclusions

The findings of stroke recurrence in lowering examination cost could be explained from two perspectives, different clinical patterns of healthcare utilization and patients'' economic status in recurrent stroke.     

Recurrent Macular Edema and Stroke Syndrome in Type 1 Diabetes Mellitus with Potent Endothelial Cell Inhibitory Autoantibodies

ObjectiveTo describe a case of type 1 diabetes mellitus with recurrent macular edema and stroke in association with potent endothelial cell inhibitory autoantibodies.MethodsThe clinical, radiologic, and biochemical data from the study patient are presented, as is the bioactivity in endothelial cells from the immunoglobulin G fraction of the patient’s serum.ResultsA 52-year-old man with a 15-year history of poorly controlled type 1 diabetes mellitus had diabetic autonomic neuropathy, gastroparesis, depression, macular edema, proliferative retinopathy, diabetic nephropathy, refractory hypertension, and transient ischemic attacks that progressed to recurrent strokes despite aspirin therapy. Magnetic resonance imaging of the brain showed multifocal, bilateral ischemic infarcts consistent with recurrent stroke affecting small vessels. The patient’s serum contained endothelial cell inhibitory autoantibodies; the titer doubled during a 2-year period when the patient required repeated focal laser to treat macular edema and experienced transient ischemic attacks. The IgG autoantibodies induced stress fiber formation and apoptosis in endothelial cells and inhibited neurite outgrowth in rat pheochromocytoma PC12 cells.ConclusionsLow concentrations of purified autoantibodies (1-2 μg/mL) induce endothelial cell contraction in vitro, suggesting a role for autoantibodies in modulating endothelial cell permeability, which may affect multiple target organs. Potent IgG autoantibodies may be a useful marker (with a possible pathophysiologic role) in an unusual syndrome characterized by poorly controlled diabetes, hypertension, dementia, and recurrent small-vessel stroke. (Endocr Pract. 2010;16:842-850)     

Overview of therapeutic potentiality of Angelica sinensis for ischemic stroke

BackgroundIschemic stroke is a common cerebrovascular disease. Due to sudden interruption of blood flow by arterial thrombus, amounts of neurons in ischemic central and penumbral regions occur necrosis and apoptosis resulting in serious injury of neurological function. Chinese medicines have a great advantage in ischemic stroke treatment and recovery, especially Angelica sinensis.PurposeThere are a large number of studies reported that Angelica injection and A. sinensis active compounds. We systematically reviewed the effects and mechanisms of A. sinensis in recent years according to the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statements, and excavated its therapeutic potentiality for exploring more effective and safe compounds for ischemic stroke precision treatment.ResultsA. sinensis extracts and active compounds, such as Z-ligustilide, 3-n-Butylphthalide, and ferulic acid have significant effects of anti-inflammation, anti-oxidative stress, angiogenesis, neurogenesis, anti-platelet aggregation, anti-atherosclerosis, protection of vessels, which contributes to improvement of neurological function on ischemic stroke.ConclusionA. sinensis is a key agent for ischemic stroke treatment, and worth deeply excavating its therapeutic potentiality with the aid of pharmacological network, computer-aided drug design, artificial intelligence, big data and multi-scale modelling techniques.     

Current advances in ischemic stroke research and therapies

With more than 795,000 cases occurring every year, stroke has become a major problem in the United States across all demographics. Stroke is the leading cause of long-term disability and is the fifth leading cause of death in the US. Ischemic stroke represents 87% of total strokes in the US, and is currently the main focus of stroke research. This literature review examines the risk factors associated with ischemic stroke, changes in cell morphology and signaling in the brain after stroke, and the advantages and disadvantages of in vivo and in vitro ischemic stroke models. Classification systems for stroke etiology are also discussed briefly, as well as current ischemic stroke therapies and new therapeutic strategies that focus on the potential of stem cells to promote stroke recovery.     

An analysis of Methylenetetrahydrofolate reductase and Glutathione S-transferase omega-1 genes as modifiers of the cerebral response to ischemia

Background

Cerebral ischemia involves a series of reactions which ultimately influence the final volume of a brain infarction. We hypothesize that polymorphisms in genes encoding proteins involved in these reactions could act as modifiers of the cerebral response to ischemia and impact the resultant stroke volume. The final volume of a cerebral infarct is important as it correlates with the morbidity and mortality associated with non-lacunar ischemic strokes.

Methods

The proteins encoded by the methylenetetrahydrofolate reductase (MTHFR) and glutathione S-transferase omega-1 (GSTO-1) genes are, through oxidative mechanisms, key participants in the cerebral response to ischemia. On the basis of these biological activities, they were selected as candidate genes for further investigation. We analyzed the C677T polymorphism in the MTHFR gene and the C419A polymorphism in the GSTO-1 gene in 128 patients with non-lacunar ischemic strokes.

Results

We found no significant association of either the MTHFR (p = 0.72) or GSTO-1 (p = 0.58) polymorphisms with cerebral infarct volume.

Conclusion

Our study shows no major gene effect of either the MTHFR or GSTO-1 genes as a modifier of ischemic stroke volume. However, given the relatively small sample size, a minor gene effect is not excluded by this investigation.     

Ischemic stroke incidence in Santa Coloma de Gramenet (ISISCOG), Spain. A community-based study

Background

In Spain, stroke is one of the major causes of death and the main cause of severe disability in people over 65 years. We analyzed the incidence of ischemic stroke, stroke subtypes, case fatality and disability at 90 days after the event in a Spanish population.

Methods

A prospective community-based register of ischemic strokes was established in Santa Coloma de Gramenet (Barcelona) [116,220 inhabitants of all ages, according to the municipal census of December 31,2001], from January 1 to December 31, 2003.Standard definitions and case finding methods were used to identify all cases in all age groups. Every patient underwent a complete clinical evaluation and systematic tests including neuroimaging (CT/MRI) and vascular studies (carotid duplex ultrasound intra and extracranial and MR angiography).

Results

Over a one year period, 196 ischemic strokes were registered [107 men; median age = 76 years (range 39–98)], being the first event in 159 patients (81.1%) and a recurrent stroke in 37 (18.9%). After age-adjustment to the European population, the incidence of ischemic stroke per 100,000 inhabitants was 172 (95% CI, 148–196); 219 (176–261) in men and 133 (105–160) in women, with an annual incidence for first ischemic stroke of 139 (118–161); 165 (128–201) in men and 115 (89–140) in women. The incidence of stroke increased with age.Stroke subtypes (TOAST classification criteria) were lacunar in 28.8%, atherothrombotic in 18.6%, cardioembolic in 26.6% and undetermined in 26.0% of patients. At 90 days, the case-fatality was 12%, and among survivors, moderate-to-severe disability was present in 45 % at 3 months.

Conclusion

This prospective community-based study shows one of the lowest incidences of stroke in Europe, as well as one of the lowest case fatality and disability rates at 90 days after stroke.

     

Bioaccessibility and safety assessment of trace elements from decoction of “Zhebawei” herbal medicines by in vitro digestion method

Studies on in vitro bioaccessibility and safety assessment of 6 elements namely Fe, Zn, Cu, Mn, As and Cd in decoction of eight commonly consumed “Zhebawei” herbal medicines were carried out. The method was based on simulation of human digestion in the gastrointestinal tract. Total content and content in extracts from gastrointestinal phases were analyzed for these elements by inductively coupled plasma atomic emission spectrometer (ICP-AES). In decoction of all 8 herbal medicines, it was found that the total content and bioaccessible concentration of these elements varied considerably among the types of herb, and the total content of each element did not show linearity with their bioaccessible content of the corresponding element. There is no risk of adverse health effects resulting from overdose of Fe, Zn, Cu, and Mn for almost all individuals by ingesting recommended maximum daily dose of these eight herbal medicines. In terms of Cd only Ophitopogin japonicum had higher total concentration and bioaccessible content than the value of suggested limit (5.4 μg/d). For total As content, only Scrophularia ningpoensis and Corydalis yanhusuo did not meet the safety standard. However, regarding bioaccessible As contents, none of the eight herbal medicines exceeded the value of the daily permissible intake of As (0.12 mg). The risk of toxicity from an element in herbal medicine might be overestimated when the total concentration but not the bioaccessible content is taken into account. In vitro digestion method is rapid, relatively simple and inexpensive, which could be helpful in conducting experiments about safety assessment of an element in herbal medicines.     

Association between TNFRSF11B gene polymorphisms and history of ischemic stroke in Italian diabetic patients

Osteoprotegerin (OPG) is a secretory glycoprotein that belongs to the tumor necrosis factor receptor family and plays a role in atherosclerosis. The present study aimed to evaluate whether OPG gene (TNFRSF11B) polymorphisms are involved in ischemic stroke in an Italian population with diabetes. Participants in a retrospective case–control study included 364 diabetic patients (180 males, 184 females) with history of ischemic stroke and 492 diabetic subjects without history of ischemic stroke (252 males, 240 females). The T245G, T950C, and G1181C polymorphisms of the OPG gene were analyzed by polymerase chain reaction and restriction fragment length polymorphism. We found that the T245G, T950C, and G1181C gene polymorphisms of the OPG gene were significantly (34.1 vs. 9.5 %, P < 0.0001; 30.8 vs. 6.3 %, P < 0.0001 and 26.4 vs. 11.6 % P < 0.0001, respectively) and independently (adjusted OR 5.15 [3.46–7.68], OR 6.63 [4.26–10.31], and OR 3.03 [2.04–4.50], respectively) associated with history of ischemic stroke. We also found that these three polymorphisms act synergistically in patients with stroke history. The TNFRSF11B gene polymorphisms studied are associated with history of ischemic stroke and synergistic effects between these genotypes might be potential markers for cerebrovascular disorders.     

Dysregulation of MicroRNAs in cancer

Background

The association between ischemic stroke and 2 single nucleotide polymorphisms (SNPs) on chromosome 12p13, rs12425791 and rs11833579 appears inconsistent across different samples. These SNPs are close to the ninjurin2 gene which may alter the risk of stroke by affecting brain response to ischemic injury. The purpose of this study was to investigate the association between these two SNPs and ischemic stroke risk, as well as prognostic outcomes in a Taiwanese sample.

Methods

We examined the relations of these two SNPs to the odds of new-onset ischemic stroke, ischemic stroke subtypes, and to the one year risk of stroke-related death or recurrent stroke following initial stroke in a case-control study. A total of 765 consecutive patients who had first-ever ischemic stroke were compared to 977 stroke-free, age-matched controls. SNPs were genotyped by Taqman fluorescent allelic discrimination assay. The association between ischemic stroke and SNPs were analyzed by multivariate logistic regression. Cox proportional hazard model was used to assess the effect of individual SNPs on stroke-related mortality or recurrent stroke.

Results

There was no significant association between SNP rs12425791 and rs11833579 and ischemic stroke after multiple testing corrections. However, the marginal significant association was observed between SNP rs12425791 and large artery atherosclerosis under recessive model (OR, 2.30; 95%CI, 1.22-4.34; q-value = 0.062). Among the 765 ischemic stroke patients, 59 died or developed a recurrent stroke. After adjustment for age, sex, vascular risk factors and baseline stroke severity, Cox proportional hazard analysis indicated that the hazard ratios were 2.76 (95%CI, 1.34-5.68; q-value, 0.02) and 2.15 (95%CI, 1.15-4.02; q-value, 0.03) for individuals with homozygous variant allele of rs12425791 and rs11833579, respectively.

Conclusions

This is a precedent study that found genetic variants of rs12425791 and rs11833579 on chromosome 12p13 are independent predictors of stroke-related mortality or stroke recurrence in patients with incident ischemic stroke in Taiwan. Further study is needed to explore the details of the physiological function and the molecular mechanisms underlying the association of this genetic locus with ischemic stroke.     

Observations on Anticoagulant Therapy in Thromboembolic Disease of the Brain

According to a recently reported study, anticoagulant therapy appears to be ineffective in thrombotic cerebrovascular disease when viewed from the standpoint of mortality, although it does control thrombosis in animals, recurrent ischemic attacks and progression of infarction in patients with stuttering strokes. The efficacy of anticoagulant therapy in preventing a catastrophic stroke is analyzed in the present report. Of 92 untreated patients followed up for an average period of 36 months, 28 suffered a recurrent stroke, only two of these being trivial. One trivial and 12 catastrophic strokes occurred in the first 16 months. Of 103 patients treated with anticoagulants for an average period of 16 months, seven had recurrent strokes, but five of these were trivial. In the first 16 months one catastrophic and four trivial strokes occurred. Anticoagulant therapy appears to be useful in preventing catastrophic strokes in selected patients in whom the risk of recurrent strokes justifies the risks involved in this treatment.     

Effect of statins in stroke prevention

PURPOSE OF REVIEW: This paper reviews recent studies into the outcomes of clinical trials in which statin therapy has been used in the prevention and treatment of strokes. RECENT DEVELOPMENTS: Epidemiologic studies found no or little association between blood cholesterol levels and stroke. Randomized trials have confirmed that LDL lowering decreased the risk of stroke, in diabetic or hypertensive patients with 'normal' LDL cholesterol at baseline, and in patients with coronary artery disease, with respectively 48, 27 and 25% reduction in stroke incidence. A meta-analysis of trials showed that the greater the LDL cholesterol reduction, the greater the intima-media thickness and stroke risk reductions. Even if statins also have 'pleiotropic' effects, their main action seems to be through LDL reduction. The Heart Protection Study only included strokes that occurred 4.6 years before--a time when the stroke event rate is low and the cardiac event rate is high, and so may not have had the power to find a true effect of LDL cholesterol lowering in preventing recurrent stroke. The Stroke Prevention by Aggressive Reduction in Cholesterol Levels (SPARCL) trial may give a definite answer because SPARCL investigators included 4732 patients with brain infarction or transient ischemic attacks and no history of myocardial infarction within 6 months of their stroke event, at a time when the expected stroke rate is very high and the myocardial infarction rate is very low. The results should be announced by mid-2006. SUMMARY: The positive effect of statins on stroke observed in trials of patients with coronary heart disease depended mainly on between-group LDL reduction, but other mechanisms could be involved. Though effective in prevention of major coronary events after a first stroke, statins have not yet been proven effective in prevention of recurrent stroke.     

Endothelial Barrier Antigenimmunoreactivity is Conversely Associated with Blood-Brain Barrier Dysfunction after Embolic Stroke in Rats

While the concept of the Neurovascular Unit (NVU) is increasingly considered for exploring mechanisms of tissue damage in ischemic stroke, immunohistochemical analyses are of interest to specifically visualize constituents like the endothelium. Changes in immunoreactivity have also been discussed to reflect functional aspects, e.g., the integrity of the blood-brain barrier (BBB). This study aimed to characterize the endothelial barrier antigen (EBA) as addressed by the antibody SMI-71 in a rat model of embolic stroke, considering FITC-albumin as BBB leakage marker and serum levels of BBB-associated matrix metalloproteinases (MMPs) to explore its functional significance. Five and 25 h after ischemia onset, regions with decreased BBB integrity exhibited a reduction in number and area of EBA-immunopositive vessels, while the stained area per vessel was not affected. Surprisingly, EBA content of remaining vessels tended to be increased in areas of BBB dysfunction. Analyses addressing this interrelation resulted in a significant and inverse correlation between the vessels’ EBA content and degree of BBB permeability. In conclusion, these data provide evidence for a functional relationship between EBA-immunoreactivity and BBB dysfunction in experimental ischemic stroke. Further studies are required to explore the underlying mechanisms of altered EBA-immunoreactivity, which might help to identify novel neuroprotective strategies.Key words: ischemic stroke, embolic model, EBA, blood-brain barrier, matrix metalloproteinase     

Cochrane systematic reviews of Chinese herbal medicines: an overview

Objectives

Our study had two objectives: a) to systematically identify all existing systematic reviews of Chinese herbal medicines (CHM) published in Cochrane Library; b) to assess the methodological quality of included reviews.

Methodology/Principal Findings

We performed a systematic search of the Cochrane Database of Systematic Reviews (CDSR, Issue 5, 2010) to identify all reviews of CHM. A total of fifty-eight reviews were eligible for our study. Twenty-one of the included reviews had at least one Traditional Chinese Medicine (TCM) practitioner as its co-author. 7 reviews didn''t include any primary study, the remaining reviews (n = 51) included a median of 9 studies and 936 participants. 50% of reviews were last assessed as up-to-date prior to 2008. The questions addressed by 39 reviews were broad in scope, in which 9 reviews combined studies with different herbal medicines. For OQAQ, the mean of overall quality score (item 10) was 5.05 (95% CI; 4.58-5.52). All reviews assessed the methodological quality of primary studies, 16% of included primary studies used adequate sequence generation and 7% used adequate allocation concealment. Of the 51 nonempty reviews, 23 reviews were reported as being inconclusive, while 27 concluded that there might be benefit of CHM, which was limited by the poor quality or inadequate quantity of included studies. 58 reviews reported searching a median of seven electronic databases, while 10 reviews did not search any Chinese database.

Conclusions

Now CDSR has included large numbers of CHM reviews, our study identified some areas which could be improved, such as almost half of included reviews did not have the participation of TCM practitioners and were not up-to-date according to Cochrane criteria, some reviews pooled the results of different herbal medicines and ignored the searching of Chinese databases.     

Recurrent posterior circulation infarction caused by anomalous occipital bony process in a young patient

Background

Structural anomaly of the cervical spine or craniocervical junction has been reported as one of the rare causes of ischemic stroke. We report a case of a young patient with recurrent posterior circulation infarction that may have been associated with an anomalous occipital bony process compressing the vertebral artery.

Case presentation

A 23-year-old man experienced recurrent posterior circulation infarction 5 times over a period of 5 years. He had no conventional vascular risk factors. Young age stroke work-up including thorough cardiac, intra- and extracranial vascular evaluation and laboratory tests for the hypercoagulable state or connective tissue disease yielded unremarkable results. An anomalous bony process from the occipital base compressing the left vertebral artery was observed on brain CT. All the recurrent strokes were explainable by the arterial thromboembolism originating from the compressed left vertebral artery. Therefore, the left vertebral artery compressed by the anomalous occipital bony process may have been the culprit behind the recurrent thromboembolic strokes in our patient. Intractable recurrent strokes even under optimal medical treatment led us to make a decision for the intervention. Instead of surgical removal of the anomalous occipital bony process, the left vertebral artery was occluded permanently by endovascular coiling after confirming that this would cause no neurological deficits or flow disturbance in the posterior circulation. There was no recurrence of stroke for 2 years after permanent occlusion of the left vertebral artery.

Conclusion

Arterial thromboembolism originating from the left vertebral artery compressed by the anomalous occipital bony process is a rare but not to be overlooked cause of posterior circulation infarction. When intractable to medical treatment, endovascular occlusion of the vertebral artery without flow disturbance to the posterior circulation may be a useful treatment option when surgical removal is not feasible.

     

Protection against Recurrent Stroke with Resveratrol: Endothelial Protection

Despite increased risk of a recurrent stroke following a minor stroke, information is minimal regarding the interaction between injurious mild cerebral ischemic episodes and the possible treatments which might be effective. The aim of the current study was to investigate recurrent ischemic stroke and whether resveratrol, a nutritive polyphenol with promising cardio- and neuro- protective properties, could ameliorate the associated brain damage. Experiments in adult rats demonstrated that a mild ischemic stroke followed by a second mild cerebral ischemia exacerbated brain damage, and, daily oral resveratrol treatment after the first ischemic insult reduced ischemic cell death with the recurrent insult (P<0.002). Further investigation demonstrated reduction of both inflammatory changes and markers of oxidative stress in resveratrol treated animals. The protection observed with resveratrol treatment could not be explained by systemic effects of resveratrol treatment including effects either on blood pressure or body temperature measured telemetrically. Investigation of resveratrol effects on the blood-brain barrier in vivo demonstrated that resveratrol treatment reduced blood-brain barrier disruption and edema following recurrent stroke without affecting regional cerebral blood flow. Investigation of the mechanism in primary cell culture studies demonstrated that resveratrol treatment significantly protected endothelial cells against an in vitro ‘ischemia’ resulting in improved viability against oxygen and glucose deprivation (39.6±6.6% and 81.3±9.5% in vehicle and resveratrol treated cells, respectively). An inhibition of nitric oxide synthesis did not prevent the improved cell viability following oxygen glucose deprivation but SIRT-1 inhibition with sirtinol partially blocked the protection (P<0.001) suggesting endothelial protection is to some extent SIRT-1 dependent. Collectively, the results support that oral resveratrol treatment provides a low risk strategy to protect the brain from enhanced damage produced by recurrent stroke which is mediated in part by a protective effect of resveratrol on the endothelium of the cerebrovasculature.     

Oxygen-Glucose Deprivation and Reoxygenation as an In Vitro Ischemia-Reperfusion Injury Model for Studying Blood-Brain Barrier Dysfunction

Ischemia-Reperfusion (IR) injury is known to contribute significantly to the morbidity and mortality associated with ischemic strokes. Ischemic cerebrovascular accidents account for 80% of all strokes. A common cause of IR injury is the rapid inflow of fluids following an acute/chronic occlusion of blood, nutrients, oxygen to the tissue triggering the formation of free radicals.Ischemic stroke is followed by blood-brain barrier (BBB) dysfunction and vasogenic brain edema. Structurally, tight junctions (TJs) between the endothelial cells play an important role in maintaining the integrity of the blood-brain barrier (BBB). IR injury is an early secondary injury leading to a non-specific, inflammatory response. Oxidative and metabolic stress following inflammation triggers secondary brain damage including BBB permeability and disruption of tight junction (TJ) integrity.Our protocol presents an in vitro example of oxygen-glucose deprivation and reoxygenation (OGD-R) on rat brain endothelial cell TJ integrity and stress fiber formation. Currently, several experimental in vivo models are used to study the effects of IR injury; however they have several limitations, such as the technical challenges in performing surgeries, gene dependent molecular influences and difficulty in studying mechanistic relationships. However, in vitro models may aid in overcoming many of those limitations. The presented protocol can be used to study the various molecular mechanisms and mechanistic relationships to provide potential therapeutic strategies. However, the results of in vitro studies may differ from standard in vivo studies and should be interpreted with caution.     

Herb-drug interaction between Styrax and warfarin: Molecular basis and mechanism

BackgroundStyrax, one of the most famous folk medicines, has been frequently used for the treatment of cardiovascular diseases and skin problems in Asia and Africa. It is unclear whether Styrax or Styrax-related herbal medicines may trigger clinically relevant herb-drug interactions.PurposeThis study was carried out to investigate the inhibitory effects of Styrax on human cytochrome P450 enzymes (CYPs) and to clarify whether this herb may modulate the pharmacokinetic behavior of the CYP-substrate drug warfarin when co-administered.Study DesignThe inhibitory effects of Styrax on CYPs were assayed in human liver microsomes (HLM), while the pharmacokinetic interactions between Styrax and warfarin were investigated in rats. The bioactive constituents in Styrax with strong CYP3A inhibitory activity were identified and their inhibitory mechanisms were carefully investigated.MethodsThe inhibitory effects of Styrax on human CYPs were assayed in vitro, while the pharmacokinetic interactions between Styrax and warfarin were studied in rats. Fingerprinting analysis of Styrax coupled with LC-TOF-MS/MS profiling and CYP inhibition assays were used to identify the constituents with strong CYP3A inhibitory activity. The inhibitory mechanism of oleanonic acid (the most potent CYP3A inhibitor occurring in Styrax) against CYP3A4 was investigated by a panel of inhibition kinetics analyses and in silico analysis.ResultsIn vitro assays demonstrated that Styrax extract strongly inhibited human CYP3A and moderately inhibited six other tested human CYPs, as well as potently inhibited warfarin 10-hydroxylation in liver microsomes from both humans and rats. In vivo assays demonstrated that compared with warfarin given individually in rats, Styrax (100 mg/kg) significantly prolonged the plasma half-life of warfarin by 2.3-fold and increased the AUC_(0-inf) of warfarin by 2.7-fold when this herb was co-administrated with warfarin (2 mg/kg) in rats. Two LC fractions were found with strong CYP3A inhibitory activity and the major constituents in these fractions were characterized by LC-TOF-MS/MS. Five pentacyclic triterpenoid acids (including epibetulinic acid, betulinic acid, betulonic acid, oleanonic acid and maslinic acid) present in Styrax were potent CYP3A inhibitors, and oleanonic acid was a competitive inhibitor against CYP3A-mediated testosterone 6β-hydroxylation.ConclusionStyrax and the pentacyclic triterpenoid acids occurring in this herb strongly modulate the pharmacokinetic behavior of warfarin via inhibition of CYP3A.     

Metabolomics study of Buyang Huanwu Tang Decoction in ischemic stroke mice by 1H NMR

The characteristic of traditional Chinese medicine (TCM) is the use of multiple components for multiple therapeutic targets. Metabolomics provides a measurement of multiparametric metabolic response in a living system to the effects of genetic or environmental modulation, which has been highly favored in evidence-based TCM study in recent years. A Chinese herbal decoction of Buyang Huanwu Tang (BHTD) has long been used for stroke treatment. In this study, nuclear magnetic resonance (NMR)-based metabolomics was conducted to examine the therapeutic effects of BHTD in a cerebral artery occlusion-induced sub-acute stroke mouse model. The brain tissues were analyzed in a nano probe using Carr-Purcell-Meiboom-Gill (CPMG) sequence for metabolic profiles. The spectral data were analyzed in conjunction with orthogonal partial least-squares discriminant analysis (OPLS-DA) to discover the metabolic effects in stroke mice and the effects of BHTD treatment. Twenty endogenous metabolites were identified. Among them, significant increase in acetone, ??-hydroxybutyrate, glucose, lactate, and alanine, and significant decrease of ??-aminobutyrate, acetate, N-acetyl aspartate, glutamate, citrate, creatine?+?phosphocreatine, choline, phosphocholine?+?glycerophosphocholine, taurine, myo-inositol, glycerol, glycolate, and adenine were found in the brain of stroke mice when compared with normal mice. OPLS-DA results showed that metabolite profiles in the brain of ischemic stroke mice, treated with BHTD, were partially reversed to normal. After BHTD treatment, the levels of most abnormal metabolites were restored. Our study suggests that NMR-based metabolomics can provide a simple and easy tool for herbal therapeutic evaluation.