Gautam Karmarkar’s research while affiliated with National Institute of Pharmaceutical Education And Research Ahmedabad and other places

Background Pregnancy may be a risk factor for stroke in females. Stroke in pregnancy influences mitochondrial dynamics as well as the inflammatory responses in mothers. However, limited studies are available that report any epigenetic changes in the offspring following a stroke in mothers. In the present study we investigate the effect of stroke in pregnancy as a possible epigenetic modifier correlated with dysfunctional mitochondrial dynamics and exacerbated inflammasome mediated apoptosis in the offsprings. Methods and Results Female and male Sprague Dawley rats were housed in the same cage in 1:2 ratio to ensure successful pregnancy. Stroke was induced by middle cerebral artery occlusion at gestational day 17. After delivery of F1 generation, bloods were collected from the dams for hormonal study. Brains were harvested from both dams and F1 generation for biochemical, histological, genetic, molecular, and mitochondrial studies. In the F1 generation of stroke induced dams, an increased mitochondrial fission and decreased mitochondrial fusion were observed as compared with normal dams and their F1 generation. Similarly, enhanced mitochondrial reactive oxygen species and depolarization were also observed in the F1 generation of stroke induced dams. Exacerbated inflammasome signaling and enhanced apoptosis were also evident in this F1 generation. Changes in histone‐methylation corresponding to increased inflammation were also observed in this F1 generation. Conclusions The present study reports the occurrence of epigenetic modifications towards mitochondrial dysfunction and exacerbated inflammasome mediated apoptosis in the F1 generation following a stroke in pregnant dams.

Stroke is one of the major causes of mortality and long-term disability worldwide. Chronic-kidney-disease (CKD) is a condition where patients have shown increased vulnerability to stroke with poor functional and cognitive outcomes. Impaired cerebral autoregulation in CKD patients may impose a high risk of stroke. To date, the mechanism of worsened stroke outcomes in CKD patients are limitedly understood. Alterations of endoplasmic-reticulum (ER) homoeostasis via modification of Sel1L-Hrd1 complex is one of the many cellular events that gets triggered following both CKD and stroke leading to accumulation of misfolded proteins, culminating in ER-stress. Therefore, the present study aims to explore the involvement of Sel1L mediated altered ER functions towards worsening of stroke outcome in CKD and further its crucial role towards white matter damage. CKD-stroke complex was induced in male Sprague-Dawley rats followed by middle-cerebral-artery occlusion. At 24 h and 7th day of reperfusion, animals were subjected to behavioral analysis followed by euthanasia, brain harvest and molecular studies. CKD-Stroke-complex animals showed aggravated neurofunctional and cognitive impairment which were further normalized by treatment of an ER-stress inhibitor. This indicates exacerbated stroke outcome in CKD-stroke-complex may be mediated by imbalanced ER-homeostasis due to decreased Sel1L expression leading to enhanced cellular death and neurodegeneration.

The progressive brain damage following ischemic stroke is primarily due to oxidative stress and activation of inflammatory pathways. Post-stroke neurodegeneration can lead to the loss of neurons and glial cells, including oligodendrocytes, contributing to demyelination. Following ischemic stroke, reperfusion results in increased intracellular calcium, generation of free radicals, and inflammation culminating in accumulation of misfolded proteins in the endoplasmic reticulum (ER) lumen augmenting the ER stress. ER stress has been shown to aggravate post-stroke neurodegeneration by triggering neuronal apoptosis and also contributing towards demyelination of neurons. To address the limitations of current stroke therapies, repurposing of drugs as future adjunctive therapy may be promising. Clemastine, an antihistaminic drug, improves post stroke outcome as evident in the present study. Male Sprague Dawley (SD) rats were treated with clemastine following ischemic stroke. Harvested brain tissues were subjected to different biochemical assays, molecular assays, and histopathological analysis. Clemastine was able to reduce infarct size, alleviate oxidative stress, improve neuronal count, and functional outcomes. Clemastine downregulated genes and proteins responsible for ER stress, apoptosis and demyelination as shown by the western blot and qPCR results. Our study suggests that clemastine may alleviate endoplasmic reticulum stress-mediated demyelination by modulating PERK/ATF4/CHOP axis, and may be used as one of the adjunctive therapies for stroke in future.

Despite rapid advances in stroke management and rehabilitation therapy, no effective treatment is available for the later recovery phase following stroke. Therefore, complementary and alternative medicine system (CAM) has emerged as promising adjunct therapy for stroke management. CAM has its own cultural and philosophical aspects with different societies that drive as an inspiration and perception of less harmful and more effective strategies for stroke rehabilitation. However, robust scientific studies are required to establish CAM as an alternative therapy adjunct to conventional stroke treatment. A thorough literature search was performed using standard web databases such as PubMed, Google Scholar, ResearchGate, Scopus using ‘complementary and alternative medicine in stroke’ as the major keyword. Research and review articles containing latest preclinical and clinical studies were primarily included in this review. Moreover, different stroke treatment strategies mentioned in ancient scriptures were also considered. CAM therapy is parallelly practiced along with clinically approved stroke therapy worldwide. It has been also reported beneficial on post-stroke neurorehabilitation in different population-based studies. Currently, CAM suffers various limitations, including defined end-point, clear outcomes, the exact mechanism of action, and proper assessment of the patient’s physical and emotional needs. Nevertheless, CAM is being used to treat various diseases globally. However, their usage pattern differs according to a population's geography and socio-cultural background. The review briefly discusses different CAM used as stroke rehabilitation therapy and their promising role in adjunct stroke management strategies.

Background Conventional post-stroke edema management strategies are limitedly successful as in multiple cases of hemorrhagic transformation is being reported. Clinically, acute-ischemic-stroke (AIS) intervention by endovascular mesenchymal stem cells (MSCs) have shown benefits by altering various signaling pathways. Our previous studies have reported that intra-arterial administration of 1*10⁵ MSCs (IA-MSCs) were beneficial in alleviating post-stroke edema by modulating PKCδ/MMP9/AQP4 axis and helpful in preserving the integrity of blood-brain-barrier (BBB). However, the role of mitochondrial dysfunction and ROS generation post-AIS cannot be overlooked in context to the alteration of the BBB integrity and edema formation through the activation of inflammatory pathways. The anti-inflammatory activity of IA-MSCs in stroke has been reported to be regulated by sirtuin-1 (SIRT-1). Hence, the relationship between SIRT-1 and AQP4 towards regulation of post-stroke edema needs to be further explored. Therefore, the present study deciphers the molecular events towards AQP4 upregulation, mitochondrial dysfunction and BBB disruption in context to the modulation of SIRT-1/PKCδ/NFκB loop by IA-MSCs administration. Methods Ovariectomized SD rats were subjected to focal ischemia. SIRT-1 activator, SIRT-1 inhibitor, NFkB inhibitor and IA-MSCs were administered at optimized dose. At 24 h of reperfusion, behavioral tests were performed, and brains were harvested following euthanasia for molecular studies. Results IA-MSCs downregulated AQP4, PKCδ and NFkB expression, and upregulated SIRT-1 expression. SIRT-1 upregulation renders mitochondrial protection via reduction of oxidative stress resulting in BBB protection. Conclusion IA-MSCs can modulate SIRT-1 mediated AQP4 expression via mitochondrial ROS reduction and modification of NFkB transcriptional regulation. Graphical Abstract