Arshad Majid

Systematic review and stratified meta-analysis of the efficacy of carnosine in animal models of ischemic stroke:

Carnosine is a naturally occurring pleotropic dipeptide which influences multiple deleterious mechanisms that are activated during stroke. Numerous published studies have reported that carnosine has robust efficacy in ischemic stroke models. To further evaluate these data, we have conducted a systematic review and meta-analysis of published studies. We included publications describing in vivo models of ischemic stroke where the neuroprotective efficacy of carnosine was being evaluated through the reporting of infarct volume and/or neurological score as outcomes. Overall efficacy was evaluated using weighted mean difference random effects meta-analysis. We also evaluated for study quality and publication bias. We identified eight publications that met our inclusion criteria describing a total of 29 comparisons and 454 animals. Overall methodological quality of studies was moderate (median = 4/9). Carnosine reduced infarct volume by 29.4% (95% confidence interval (CI), 24.0% to 34.9%; 29 comparisons). A clear dose-response effect was observed, and efficacy was reduced when carnosine was administered more than 6 h after ischemia. Our findings suggest that carnosine administered before or after the onset of ischemia exhibits robust efficacy in experimental ischemic stroke. However, the methodological quality of some of the studies was low and testing occurred only in healthy young male animals.

Enhanced acute anti-inflammatory effects of CORM-2-loaded nanoparticles via sustained carbon monoxide delivery

The aim of this study was to enhance the anti-inflammatory effects of carbon monoxide (CO) via sustained release of CO from carbon monoxide-releasing molecule-2-loaded lipid nanoparticles (CORM-2-NPs). CORM-2-NPs were prepared by hot high pressure homogenization method using trilaurin as a solid lipid core and Tween 20/Span 20/Myrj S40 as surfactant mixture. The physicochemical properties of CORM-2-NPs were characterized and CO release from CORM-2-NPs was assessed by myoglobin assay. In vitro anti-inflammatory effects were evaluated by nitric oxide assay in lipopolysaccharide-stimulated RAW 264.7 macrophages. In vivo anti-inflammatory activity was investigated by measuring paw volumes and histological examination in carrageenan-induced rat paw edema. Spherical CORM-2-NPs were around 100nm with narrow particle size distribution. The sustained CO release from CORM-2-NPs was observed and the half-life of CO release increased up to 10 times compared with CORM-2 solution. CORM-2-NPs showed enhanced in vitro anti-inflammatory effects by inhibition of nitric oxide production. Edema volume in rat paw was significantly reduced after treatment with CORM-2-NPs. Taken together, CORM-2-NPs have a great potential for CO therapeutics against inflammation via sustained release of CO.

Enhanced anti-rheumatic activity of methotrexate-entrapped ultradeformable liposomal gel in adjuvant-induced arthritis rat model

The aim of this study is to investigate in vivo anti-rheumatic activity of methotrexate-entrapped ultradeformable liposomal gel (MTX-UDLs-gel) in adjuvant-induced arthritis rat model. Methotrexate-entrapped ultradeformable liposomes (MTX-UDLs) with the optimal phosphatidylcholine to Tween 80 ratio (7:3, w/w) were incorporated into 1% Carbopol gel. MTX-UDLs-gel was characterized in terms of appearance, clarity, homogeneity, pH and drug content. The permeation of MTX-UDLs-gel across rat skin was investigated using Franz diffusion cell. In vivo anti-rheumatic activity of MTX-UDLs-gel was assessed in terms of edema volume, paw edema and leukocyte infiltration scores, histopathological analysis and inflammatory cytokines level in complete Freunds adjuvant (CFA)-induced arthritis rat model. MTX-UDLs-gel showed good homogeneity and clarity, neutral pH and about 99.5% drug content. The cumulative amount of MTX permeated for 24h from MTX-UDLs-gel (164.6μg) was 1.5 and 2.15 times higher than that of MTX-CLs-gel (113.3μg) and MTX-plain-gel (76.6μg), respectively. MTX-UDLs-gel significantly alleviated the severity of inflammation by reducing edema volume, histological scores and accumulation of neutrophils and improving tissue architecture in CFA-induced arthritis rat model. MTX-UDLs-gel effectively suppressed the expression of pro-inflammatory cytokines, TNF-α and IL-1β, in paw tissues. In conclusion, the developed MTX-UDLs-gel has a great potential for effective delivery of MTX into the inflamed joints in rheumatoid arthritis.

Transcutaneous Auricular Vagus Nerve Stimulation with Concurrent Upper Limb Repetitive Task Practice for Poststroke Motor Recovery: A Pilot Study

BACKGROUND Invasive vagus nerve stimulation (VNS) has the potential to enhance the effects of physiotherapy for upper limb motor recovery after stroke. Noninvasive, transcutaneous auricular branch VNS (taVNS) may have similar benefits, but this has not been evaluated in stroke recovery. We sought to determine the feasibility of taVNS delivered alongside upper limb repetitive task-specific practice after stroke and its effects on a range of outcome measures evaluating limb function. MATERIALS AND METHODS Thirteen participants at more than 3 months postischemic stroke with residual upper limb dysfunction were recruited from the community of Sheffield, United Kingdom (October-December 2016). Participants underwent 18 × 1-hour sessions over 6 weeks in which they made 30-50 repetitions of 8-10 arm movements concurrently with taVNS (NEMOS; Cerbomed, Erlangen, Germany, 25 Hz, .1-millisecond pulse width) at maximum tolerated intensity (mA). An electrocardiogram and rehabilitation outcome scores were obtained at each visit. Qualitative interviews determined the acceptability of taVNS to participants. RESULTS Median time after stroke was 1.16 years, and baseline median/interquartile range upper limb Fugl-Meyer (UFM) score was 63 (54.5-99.5). Participants attended 92% of the planned treatment sessions. Three participants reported side effects, mainly fatigue, but all performed mean of more than 300 arm repetitions per session with no serious adverse events. There was a significant change in the UFM score with a mean increase per participant of 17.1 points (standard deviation 7.8). CONCLUSION taVNS is feasible and well-tolerated alongside upper limb repetitive movements in poststroke rehabilitation. The motor improvements observed justify a phase 2 trial in patients with residual arm weakness.

Aerobic exercise interventions reduce blood pressure in patients after stroke or transient ischaemic attack: a systematic review and meta-analysis

Objective Secondary vascular risk reduction is critical to preventing recurrent stroke. We aimed to evaluate the effect of exercise interventions on vascular risk factors and recurrent ischaemic events after stroke or transient ischaemic attack (TIA). Design Intervention systematic review and meta-analysis. Data sources OVID MEDLINE, PubMed, The Cochrane Library, Web of Science, The National Institute for Health and Care Excellence, TRIP Database, CINAHL, PsycINFO, SCOPUS, UK Clinical Trials Gateway and the China National Knowledge Infrastructure were searched from 1966 to October 2017. Eligibility criteria Randomised controlled trials evaluating aerobic or resistance exercise interventions on vascular risk factors and recurrent ischaemic events among patients with stroke or TIA, compared with control. Results Twenty studies (n=1031) were included. Exercise interventions resulted in significant reductions in systolic blood pressure (SBP) −4.30 mm Hg (95% CI −6.77 to −1.83) and diastolic blood pressure −2.58 mm Hg (95% CI −4.7 to −0.46) compared with control. Reduction in SBP was most pronounced among studies initiating exercise within 6 months of stroke or TIA (−8.46 mm Hg, 95% CI −12.18 to −4.75 vs −2.33 mm Hg, 95% CI −3.94 to −0.72), and in those incorporating an educational component (−7.81 mm Hg, 95% CI −14.34 to −1.28 vs −2.78 mm Hg, 95% CI −4.33 to −1.23). Exercise was also associated with reductions in total cholesterol (−0.27 mmol/L, 95% CI −0.54 to 0.00), but not fasting glucose or body mass index. One trial reported reductions in secondary vascular events with exercise, but was insufficiently powered. Summary Exercise interventions can result in clinically meaningful blood pressure reductions, particularly if initiated early and alongside education.

Role of Autophagy in Endothelial Damage and Blood–Brain Barrier Disruption in Ischemic Stroke

The global burden of neurological diseases including stroke has significantly increased,1 and an urgent need exists to develop new treatment strategies. Impairment of autophagic regulation has been observed in diseases including neurodegenerative diseases and ischemic stroke, suggesting that modulation of autophagy could be a potential therapeutic target.2 Endothelial cells (ECs) maintain homeostasis by regulating the vascular tone and permeability and endothelial dysfunction is associated with diverse cardiovascular diseases (CVDs). The integrity of the blood–brain barrier (BBB), which shows selective permeability for substances into the brain, is significantly impaired under ischemic stroke. This review focuses on autophagy in endothelial dysfunction in the context of ischemic stroke and potential targets for therapeutic manipulation. Autophagy or autophagocytosis is an evolutionarily conserved mechanism for the degradation and recycling of cellular organelles and protein.2 It occurs continually at basal levels in cells and contributes to the maintenance of cellular homeostasis. When external nutrient supplies are limited, cells attempt to generate their energy by degrading and recycling macromolecules and cellular organelles by autophagy.3 Autophagy is also an important defense mechanism against stress including oxidative stress and infection, enabling cellular repair, or clearance of pathogens.1,2 Defects in autophagy flux may lead to the accumulation of damaged or senescent proteins and abnormal protein aggregates, and this is closely associated with human diseases including neurodegenerative, cardiovascular, and metabolic diseases, as well as cancer.2,4 In contrast to the protective role of autophagy in maintaining basal cellular homeostasis, excessive autophagy may also cause dysregulation of catabolic activity and maladaptation to cellular stress, leading to autophagic cell death.5 Accumulating evidence shows that modulating the level of autophagy by targeting specific regulatory molecules in the autophagy machinery may impact disease onset or disease …

Animal models of multiple sclerosis: From rodents to zebrafish

Multiple sclerosis (MS) is a chronic, immune-mediated demyelinating disease of the central nervous system. Animal models of MS have been critical for elucidating MS pathological mechanisms and how they may be targeted for therapeutic intervention. Here we review the most commonly used animal models of MS. Although these animal models cannot fully replicate the MS disease course, a number of models have been developed to recapitulate certain stages. Experimental autoimmune encephalomyelitis (EAE) has been used to explore neuroinflammatory mechanisms and toxin-induced demyelinating models to further our understanding of oligodendrocyte biology, demyelination and remyelination. Zebrafish models of MS are emerging as a useful research tool to validate potential therapeutic candidates due to their rapid development and amenability to genetic manipulation.

Methylglyoxal induced advanced glycation end products (AGE)/receptor for AGE (RAGE)-mediated angiogenic impairment in bone marrow-derived endothelial progenitor cells

ABSTRACT Endothelial cells (ECs) maintain the structure and function of blood vessels and are readily exposed to exogenous and endogenous toxic substances in the circulatory system. Bone marrow-derived endothelial progenitor cells (EPCs) circulate in the blood and differentiate to EC, which are known to participate in angiogenesis and regeneration of injured vessels. Dysfunction in EPC contributes to cardiovascular complications in patients with diabetes, but the precise molecular mechanisms underlying diabetic EPC abnormalities are not completely understood. The aim of this study was to investigate the mechanisms underlying diabetic EPC dysfunction using methylglyoxal (MG), an endogenous toxic diabetic metabolite. Data demonstrated that MG decreased cell viability and protein expression of vascular endothelial growth factor receptor (VEGFR)-2 associated with functional impairment of tube formation in EPC. The generation of advanced glycation end (AGE) products was increased in EPC following exposure to MG. Blockage of receptor for AGE (RAGE) by FPS-ZM1, a specific antagonist for RAGE, significantly reversed the decrease of VEGFR-2 protein expression and angiogenic dysfunction in MG-incubated EPC. Taken together, data demonstrated that MG induced angiogenic impairment in EPC via alterations in the AGE/RAGE-VEGFR-2 pathway which may be utilized in the development of potential therapeutic and preventive targets for diabetic vascular complications.

Very delayed remote ischemic post-conditioning induces sustained neurological recovery by mechanisms involving enhanced angioneurogenesis and peripheral immunosuppression reversal

Ischemic conditioning is defined as a transient and subcritical period of ischemia integrated in an experimental paradigm that involves a stimulus of injurious ischemia, activating endogenous tissue repair mechanisms that lead to cellular protection under pathological conditions like stroke. Whereas ischemic pre-conditioning is irrelevant for stroke treatment, ischemic post-conditioning, and especially non-invasive remote ischemic post-conditioning (rPostC) is an innovative and potential strategy for stroke treatment. Although rPostC has been shown to induce neuroprotection in stroke models before, resulting in some clinical trials on the way, fundamental questions with regard to its therapeutic time frame and its underlying mechanisms remain elusive. Hence, we herein used a model of non-invasive rPostC of hind limbs after cerebral ischemia in male C57BL6 mice, studying the optimal timing for the application of rPostC and its underlying mechanisms for up to 3 months. Mice undergoing rPostC underwent three different paradigms, starting with the first cycle of rPostC 12 h, 24 h, or 5 days after stroke induction, which is a very delayed time point of rPostC that has not been studied elsewhere. rPostC as applied within 24 h post-stroke induces reduction of infarct volume on day three. On the contrary, very delayed rPostC does not yield reduction of infarct volume on day seven when first applied on day five, albeit long-term brain injury is significantly reduced. Likewise, very delayed rPostC yields sustained neurological recovery, whereas early rPostC (i.e., <24 h) results in transient neuroprotection only. The latter is mediated via heat shock protein 70 that is a well-known signaling protein involved in the pathophysiological cellular cascade of cerebral ischemia, leading to decreased proteasomal activity and decreased post-stroke inflammation. Very delayed rPostC on day five, however, induces a pleiotropic effect, among which a stimulation of angioneurogenesis, a modulation of the ischemic extracellular milieu, and a reversal of the stroke-induced immunosuppression occur. As such, very delayed rPostC appears to be an attractive tool for future adjuvant stroke treatment that deserves further preclinical attention before large clinical trials are in order, which so far have predominantly focused on early rPostC only.

Safety and tolerability of Transcutaneous Vagus Nerve stimulation in humans; a systematic review

BACKGROUND Transcutaneous Vagus Nerve stimulation (tVNS) may be an alternative to surgically implanted VNS for epilepsy and other diseases. However, its safety and tolerability profile is unclear. OBJECTIVE We performed a systematic review of treatment harms from tVNS in humans. METHODS A systematic published and grey literature search was carried out to identify studies which deployed tVNS in human subjects. Study authors were contacted for safety/tolerability data if these were not available in the publication. Databases were searched from 1966 to May 2017. We noted study type, population, stimulation parameters, type and prevalence of side effects and/or serious adverse events (SAE). We also noted whether side effects/SAE were considered to be related to the tVNS and the proportion of participants dropping out of studies due to side effects. RESULTS 51 studies were included comprising a total of 1322 human subjects receiving tVNS. The most common side effects were: local skin irritation from electrode placement (240 participants, 18.2%), headache (47, 3.6%) and nasopharyngitis (23, 1.7%). Whilst heterogeneity in overall side effect event rates between studies was not accounted for by the frequency (Hz) or pulse width (ms) of stimulation, a minority (35 participants (2.6%)) dropped out of studies due to side effects. Overall, 30 SAE occurred but only 3 were assessed by the relevant researchers to be possibly caused by tVNS. CONCLUSION tVNS is safe and well tolerated at the doses tested in research studies to date.