Permphan Dharmasaroja

Bone marrow-derived mesenchymal stem cells for the treatment of ischemic stroke

Bone marrow-derived mesenchymal stem cells (MSCs) have great potential as therapeutic agents in stroke management, since they are easily accessible and can be rapidly expanded ex vivo for autologous transplantation. Increasing evidence suggests that bone marrow cells migrate throughout the brain and differentiate into neurons and glial cells. Both non-human and human MSCs have been used to treat stroke in murine models with satisfactory results. Several factors, such as transdifferentiation, induction of neurogenesis and angiogenesis, neuroprotection, and activation of endogenous neurorestorative processes, contribute to the benefits of MSCs in the ischemic brain. Many variables, including types of MSCs, cell dose, timing of treatment, route of cell delivery, and characteristics of stroke patients, influence the efficacy of MSC treatment of stroke. Although the first trials of autologous MSC therapy in stroke patients showed promising results, the optimal approach for different clinical settings has yet to be determined. The fundamental properties of MSCs and their potential short-term and long-term toxicities also need to be determined before moving forward to use of these cells in clinical practice.

Sports-related internal carotid artery dissection: pathogenesis and therapeutic point of view.

Background:Extracranial and intracranial internal carotid artery (ICA) dissections following sports-related activities have been reported as a result of blunt traumatic injuries. The incidence of carotid artery dissection in sports is not known. Failure of physicians to suspect a dissection in the context of a minor injury or to obtain a history from the patient can lead to permanent neurologic deficits. Review Summary:The presentation of this entity is variable. We present 2 cases of ICA dissection with differences in causative mechanism and management in order to emphasize the importance of a physicians awareness, and we review the literature on this subject. Conclusions:Pathogenesis of sports-related ICA dissections may be multifactorial. Structural aberrations in the arterial walls and defective connective tissue components are assumed in some patients. Several genes have been shown to be candidates for the connective tissue aberrations. Since sports-related ICA dissection can occur extracranially or intracranially, the combined use of proper diagnostic techniques that provides information on the extracranial and intracranial vessels is recommended. Although the mechanisms and treatment modalities for intracranial and extracranial dissections might be different, the initial steps of evaluation and stabilization should be standardized for both. There is no randomized controlled study for the best treatment or management of ICA dissection.

Specificity of autoantibodies to epitopes of myelin proteins in multiple sclerosis

An autoimmune response to one or more myelin-protein components is thought to be part of the pathogenesis of multiple sclerosis (MS). The immunodominant-autoantibody epitope may be localized on a linear peptide segment, on a conformation-sensitive epitope, or on an epitope resulting from post-translational modifications. Primary, secondary, and tertiary structures of myelin proteins may determine the specific site for binding of autoantibodies. A myelin protein-specific autoantibody can bind to either a linear or conformational epitope, whereas all of the T cell epitopes are linear. At present, the conformational epitopes of myelin proteins have not been identified; most of the methods used to identify the myelin-protein epitopes corresponding to the pathogenesis of multiple sclerosis are involved in the linear epitope mapping. Polymorphism or mutations may cause inappropriate expression of the myelin proteins with alterations to their linear and/or conformational epitopes, and make them susceptible to autoantibody binding, especially if these changes occur at the surface of the protein. This review focuses on the specificity of autoantibodies to the epitopes of myelin proteins and correlates this to the structures of proteins. Factors that influence the expression of myelin-protein epitopes such as the alpha-helical or beta-sheet structure of the protein, the tri-proline site, and the post-translational modifications as well as physicochemical properties of amino acid changed are included.

Neuroprotective Effects of Alpha-Mangostin on MPP+-Induced Apoptotic Cell Death in Neuroblastoma SH-SY5Y Cells

In vitro studies have shown that extracts from mangosteen (Garcinia mangostana Linn.) act as antioxidants and cytoprotective agents against oxidative damage. The protective effect of alpha-mangostin, the major xanthone found in the pericarp of the mangosteen, in cellular models of Parkinsons disease (PD), has not been investigated. This study aims to investigate whether alpha-mangostin could protect SH-SY5Y neuroblastoma cells from MPP+-induced apoptosis. The effects of alpha-mangostin on MPP+-induced cell death were evaluated with a cell viability assay, staining for nuclear DNA morphology, flow cytometry for apoptotic cells and reactive oxygen species (ROS) production, quantitative real-time PCR for the expression of p53, Bax, and Bcl-2, and western blot analysis for cleaved caspase-3. Concomitant treatment with alpha-mangostin attenuated the effect of MPP+ on cell viability and apoptotic cell death. Alpha-mangostin reduced ROS formation induced by MPP+. Bax/Bcl-2 expression ratio and expression of p53 were significantly lower in cells cocultured with alpha-mangostin and MPP+. The cotreated cells showed a significant decrease in activated caspase-3 compared with MPP+ treatment alone. Our data suggest that cytoprotection of alpha-mangostin against MPP+-induced apoptosis may be associated with the reduction of ROS production, modulating the balance of pro- and antiapoptotic genes, and suppression of caspase-3 activation.

Intravenous Thrombolysis in Thai Patients with Acute Ischemic Stroke: Role of Aging

BACKGROUND Intravenous thrombolysis is a standard treatment in eligible acute ischemic stroke (AIS) patients. However, the advisability of treating patients >80 years of age is still debated. The aim of this study was to evaluate the role of aging on the outcomes in Thai patients treated with intravenous thrombolysis. METHODS Patients with AIS treated with intravenous recombinant tissue-plasminogen activator (rtPA) between June 2007 and November 2010 were included. The demographics and measured outcome variables were compared between patients ≤70 and >70 years of age. Patients were also classified into 4 subgroups by the age ranges: ≤60 years, 61 to 70 years, 71 to 80 years, and ≥81 years of age. RESULTS Two hundred sixty-one patients were included. Seventeen patients (6.5%) were >80 years old. Higher mortality (20.2% vs 5.1%; P < .001) and symptomatic intracerebral hemorrhage (7.7% vs 1.2%; P = .004) were found in the patients >70 years of age when compared with younger patients, and the rate of favorable outcome was lower (38.1% vs 55.4%; P = .010). Higher mortality rates were seen with increasing age: 3%, 8%, 20%, and 21% in patients aged ≤60, 61 to 70, 71 to 80, and ≥81 years of age, respectively. CONCLUSIONS Thai stroke patients >70 years of age may carry a higher risk of mortality when treated with intravenous rtPA compared to patients ≤70 years of age.

In vivo characterization of the role of tissue‐specific translation elongation factor 1A2 in protein synthesis reveals insights into muscle atrophy

Translation elongation factor 1A2 (eEF1A2), uniquely among translation factors, is expressed specifically in neurons and muscle. eEF1A2‐null mutant wasted mice develop an aggressive, early‐onset form of neurodegeneration, but it is unknown whether the wasting results from denervation of the muscles, or whether the mice have a primary myopathy resulting from loss of translation activity in muscle. We set out to establish the relative contributions of loss of eEF1A2 in the different tissues to this postnatal lethal phenotype. We used tissue‐specific transgenesis to show that correction of eEF1A2 levels in muscle fails to ameliorate the overt phenotypic abnormalities or time of death of wasted mice. Molecular markers of muscle atrophy such as Fbxo32 were dramatically upregulated at the RNA level in wasted mice, both in the presence and in the absence of muscle‐specific expression of eEF1A2, but the degree of upregulation at the protein level was significantly lower in those wasted mice without transgene‐derived expression of eEF1A2 in muscle. This provides the first in vivo confirmation that eEF1A2 plays an important role in translation. In spite of the inability of the nontransgenic wasted mice to upregulate key atrogenes at the protein level in response to denervation to the same degree as their transgenic counterparts, there were no measurable differences between transgenic and nontransgenic wasted mice in terms of weight loss, grip strength, or muscle pathology. This suggests that a compromised ability fully to execute the atrogene pathway in denervated muscle does not affect the process of muscle atrophy in the short term.

Increased Plasma Soluble Thrombomodulin Levels in Cardioembolic Stroke

Soluble thrombomodulin (sTM) has been proposed as a potential marker of ischemic stroke. Results from previous studies remain controversial among different populations. We performed an analysis of plasma levels of sTM in Thai patients with acute ischemic stroke and determined whether sTM levels correlate with stroke subtypes, severity, and risk factors. Ninety-three patients and 76 controls were enrolled. Blood samples were obtained within 24 hours after stroke onset. Plasma sTM levels, measured using quantitative enzyme-linked immunosorbent assay, were significantly higher in patients than controls (P < .005), with the mean ±standard deviation (SD) levels of 3.08 ± 1.05 and 2.57 ± 1.15 ng/mL, respectively. Plasma levels of sTM in patients with cardioembolic subtype were significantly higher than in patients with other stroke subtypes, with the mean ± SD levels of 3.79 ± 1.26, 2.38 ± 0.68 (P < .009), and 2.38 ± 0.44 (P < .05) ng/mL for cardioembolism, large artery atherosclerosis, and small artery occlusion, respectively. Plasma sTM levels were not associated with stroke severity and risk factors of stroke; however, there was a slight relationship between high sTM levels and the presence of atrial fibrillation in the patient group. In conclusion, plasma sTM levels were increased in Thai patients with cardioembolic stroke and may be a potential marker during the acute phase.

Outcomes of Thai patients with acute ischemic stroke after intravenous thrombolysis

UNLABELLED The purpose of this study was to assess outcomes in Thai patients after treatment with intravenous recombinant tissue plasminogen activator (rtPA) and to determine the factors associated with good outcome and death. METHODS Patients with acute ischemic stroke who were treated with intravenous rtPA at Thammasat University Hospital between June 2007 and April 2010 were included. The measured outcome variables were good outcome (mRS 0,1) and death at 3 months. Stepwise multivariable analyses were performed by including the prespecified factors that were associated with the measured outcome variables in the univariate analysis. RESULTS The sample size was 197 patients. At 3 months, 93 patients (47%) had good outcomes while 23 patients (12%) died within the same period. Severe stroke (OR 0.19, 95% CI 0.08-0.44, p-value <0.0001) and history of hypertension (OR 0.39, 95% CI 0.16-0.93, p-value=0.033) were independently related to bad outcome at 3 months, while receiving intravenous nicardipine (OR 2.76, 95% CI 1.09-6.94, p-value=0.032) was associated with good outcome. Severe stroke (OR 5.89, 95% CI 1.29-26.85, p-value=0.022) and pretreatment high blood glucose levels (OR 8.06, 95% CI 1.21-53.62, p-value=0.031) each were independently associated with patient death. CONCLUSIONS Standard-dose intravenous rtPA in a cohort of Thai patients led to better clinical outcomes and comparable death rates when compared to other Asian cohorts receiving intravenous rtPA. Several factors were independently associated with patient outcomes at 3 months.

Differential Expression of Tyrosine Hydroxylase Protein and Apoptosis-Related Genes in Differentiated and Undifferentiated SH-SY5Y Neuroblastoma Cells Treated with MPP(.).

The human neuroblastoma SH-SY5Y cell line has been used as a dopaminergic cell model for Parkinsons disease research. Whether undifferentiated or differentiated SH-SY5Y cells are more suitable remains controversial. This study aims to evaluate the expression of apoptosis-related mRNAs activated by MPP+ and evaluate the differential expression of tyrosine hydroxylase (TH) in undifferentiated and retinoic acid- (RA-) induced differentiated cells. The western blot results showed a gradual decrease in TH in undifferentiated cells and a gradual increase in TH in differentiated cells from days 4 to 10 after cell plating. Immunostaining revealed a gradual increase in TH along with neuritic outgrowth in differentiated cells on days 4 and 7 of RA treatment. For the study on cell susceptibility to MPP+ and the expression of apoptosis-related genes, MTT assay showed a decrease in cell viability to approximately 50% requiring 500 and 1000 μM of MPP+ for undifferentiated and RA-differentiated cells, respectively. Using real-time RT-PCR, treatment with 500 μM MPP+ led to significant increases in the Bax/Bcl-2 ratio, p53, and caspase-3 in undifferentiated cells but was without significance in differentiated cells. In conclusion, differentiated cells may be more suitable, and the shorter duration of RA differentiation may make the SH-SY5Y cell model more accessible.

Intracerebral hemorrhage following intravenous thrombolysis in Thai patients with acute ischemic stroke

In Asia, there is limited information regarding symptomatic intracerebral hemorrhage (ICH) in patients treated with intravenous (iv) recombinant tissue plasminogen activator (rtPA). The aim of this study was to identify independent factors associated with symptomatic ICH following iv rtPA. The study included 192 patients with acute ischemic stroke who were treated with iv rtPA. Baseline characteristics were compared between patients with or without ICH. Symptomatic ICH occurred in 5.7% of patients and asymptomatic ICH in 13.0% of patients. An international normalized ratio (INR) ≥1.0 (odds ratio [OR]=4.89, p=0.036), atrial fibrillation (OR=7.21, p=0.009) and blood glucose concentration >8.325 mmol/L (OR=9.00, p=0.004), were independent risk factors for symptomatic ICH. Atrial fibrillation (OR=3.56, p=0.012) and severe stroke (National Institutes of Health Stroke Scale ≥15; OR=8.94, p<0.001) were independent risk factors for asymptomatic ICH. The prevalence of symptomatic ICH following iv rtPA in Thai patients was comparable to previous studies.