scholarly journals Ischemic Stroke Reduces Bone Perfusion and Alters Osteovascular Structure

2019 ◽  
Author(s):  
Nicholas J. Hanne ◽  
Andrew J. Steward ◽  
Carla Geeroms ◽  
Elizabeth D. Easter ◽  
Hannah L. Thornburg ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Blood Vessels ◽  
Bone Remodeling ◽  
Relative Number ◽  
Exercise Group ◽  
Artery Occlusion ◽  
Stroke Recovery ◽  
Aerobic Activity ◽  
Femoral Metaphysis ◽  
Tibial Metaphysis

AbstractRationaleStroke patients lose bone mass and experience fracture at an elevated rate. Although functional intraosseous vasculature is necessary for skeletal maintenance, the effect of stroke on osteovasculature is unknown.ObjectiveTo characterize changes to osteovascular function, structure, and composition following mild-to-moderate-severity ischemic stroke in mice, both with and without exercise therapy.Methods and ResultsTwelve-week-old male mice (n=27) received either a stroke (middle cerebral artery occlusion) or sham procedure, followed by four weeks of daily treadmill or sedentary activity. Intraosseous perfusion, measured weekly in the proximal tibial metaphysis, was reduced by stroke for two weeks. In the second week of recovery, exercise nearly restored perfusion to sham levels, and perfusion tended to be lower in the stroke-affected limb. At the conclusion of the study, osteovascular structure was assessed with contrast-enhanced computed tomography in the distal femoral metaphysis. Stroke significantly increased osteovascular volume and branching but reduced the relative number of blood vessels close to bone surfaces (6-22 µm away) and increased the relative number more than 52 µm away. These differences in vessel proximity to bone were driven by changes in the stroke-exercise group, indicating compounded effects of stroke and exercise. Exercise, but not stroke, nearly reduced the amount of osteogenic Type H blood vessels in the proximal tibial metaphysis, quantified with immunofluorescence microscopy.ConclusionsThis study is the first to examine the effects of stroke on osteovasculature. Stroke increased the amount of osteovasculature, but since blood vessels close to bone are associated with bone remodeling, the shift in osteovascular structure could play a role in bone loss following stroke. The exercise-induced reduction in the amount of Type H vessels and the stroke-exercise effect on osteovascular structure suggest moderate aerobic activity may have detrimental effects on bone remodeling during early stroke recovery.

Abstract TP79: Inhibition of Toll Like Receptor-4 (tlr4) Improves Neurobehavioral Outcomes After Acute Ischemic Stroke in Diabetic Rats

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Yasir Abdul ◽  
Mohammed Abdelsaid ◽  
Wieguo Li ◽  
Guangkuo Dong ◽  
Adviye Ergul
Keyword(s):  
Ischemic Stroke ◽  
Immune System ◽  
Functional Outcomes ◽  
Therapeutic Potential ◽  
Adaptive Immune System ◽  
Artery Occlusion ◽  
Stroke Recovery ◽  
Microvascular Endothelial Cell ◽  
Poor Recovery ◽  
Tlr4 Receptor

Introduction: Diabetes increases the risk of occurrence and poor recovery of ischemic stroke injury. Activation of adaptive immune system and resulting inflammation contributes to neurovascular injury and deterioration of neurological functions post stroke in diabetes. We have shown that activation of TLR4, a key player in the innate immune system, decreases brain microvascular endothelial cell survival after hypoxic injury in diabetic conditions. Our previous work also demonstrated greater bleeding/edema and poor recovery after stroke in diabetes. Current study tested the hypothesis that activation of TLR4 contributes to worsened stroke injury in diabetes and its inhibition can improve functional outcomes. Methods: Low dose of Streptozotocin (30mg/kg) and high fat diet were used to induce type 2 diabetes in male Wistar rats. Middle cerebral artery occlusion for 60 mins was performed in 13 weeks old animals. Expression of TLR4 receptor in brain homogenates and cerebral microvasculature were assessed by immunoblotting (relative density). Another set of animals was treated with TLR4 inhibitor TAK242 (3mg/kg; i.p. after reperfusion, 24 and 48 hours). Neurobehavioral deficits were measured by composite score and adhesive removal test at baseline, day 1 and 3 post ischemic stroke. Results: Ischemic stroke increased the expression of TLR4 receptor in ischemic hemisphere (0.50±0.06 sham, 0.68±0.02 control and 1.24±2.0* diabetic; *p<0.05 vs sham) as well as in microvasculature (0.55±035 sham, 1.34±0.24 control and 9.49±2.5* diabetic; *p<0.05 vs sham) and this was significantly higher in diabetic animals. Diabetes worsened functional outcomes and inhibition of TLR4 significantly improved the deficits (Table). Conclusions: Our findings that TLR4 is highly upregulated in the microvasculature and that beneficial effects of TLR4 inhibition are more profound in diabetes suggest that vascular TLR4 holds a therapeutic potential for stroke recovery in diabetes.

Abstract TP116: Effect of Voluntary Physical Activity on Circulating LG3 and Its Impact on Ischemic Stroke

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Ifechukwude Joachim Biose ◽  
Katie E Salmeron ◽  
Anthony Parker ◽  
Ann Stowe ◽  
Gregory Bix
Keyword(s):  
Physical Activity ◽  
Ischemic Stroke ◽  
Infarct Volume ◽  
Exercise Group ◽  
Artery Occlusion ◽  
Control Group ◽  
Lesion Volume ◽  
Ischemic Lesion ◽  
Voluntary Physical Activity ◽  
Wheel Activity

Physical activity (PA) is neuroprotective. However, the mechanism for the benefit of PA prior to ischemic stroke is not well understood. Circulating LG3 levels, a 25-kDa protein fragment of brain extracellular matrix proteoglycan (perlecan), increases with PA in humans. We showed that LG3 significantly reduces infarct volume following ischemic stroke. The aim of this study is to assess whether LG3 concentration increases with voluntary physical activity in mice and to determine how circulating LG3 concentration, prior to ischemic stroke, influences outcomes. Male mice (C57BL/6J, 8-9 weeks old, 21–24 g) were randomized into sedentary control group (individually housed in motorized running wheel cages with applied brakes) and an exercise group with access to running wheels. Blood draws were collected via submental method on day 1, 7, 14 and 20 of wheel activity prior to middle cerebral artery occlusion (MCAO), to evaluate LG3 concentration in serum. Following three weeks of voluntary PA or sedentary condition, 25 mice (sedentary n=13, exercise n=12) underwent transient distal MCAO for 60 min and were recovered for three days. In another study, 29 mice (sedentary n=15, exercise n=14) underwent transient proximal MCAO for 60 min. Calf muscles (soleus and gastrocnemius) and brain samples were collected for histology, protein analysis, and infarct volume assessment. We show that voluntary PA significantly reduces ischemic lesion volume compared to sedentary controls, following distal MCAO (15.2±8 vs 5.3±2 mm 3 ; P<0.0001, Figure 1). The analysis of LG3 concentration, neurofunction, as well as brain and muscle samples are currently ongoing. We expect that the findings will link LG3 concentration to the volume of exercise as well as the neuroprotection it confers in the setting of ischemic stroke.

scholarly journals Post-stroke dendritic arbor regrowth – a cortical repair process requiring the actin nucleator Cobl

2021 ◽  
Author(s):  
Yuanyuan Ji ◽  
Dennis Koch ◽  
Jule González Delgado ◽  
Madlen Günther ◽  
Otto W. Witte ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Molecular Mechanisms ◽  
Primary Motor Cortex ◽  
Recovery Process ◽  
Repair Process ◽  
Artery Occlusion ◽  
Stroke Recovery ◽  
Dendritic Arbor ◽  
Post Stroke ◽  
Actin Nucleator

AbstractIschemic stroke is a major cause of death and long-term disability. We demonstrate that middle cerebral artery occlusion in mice leads to a strong decline in dendritic arborization of penumbral neurons. These defects were subsequently repaired by an ipsilateral recovery process requiring the actin nucleator Cobl. Ischemic stroke and excitotoxicity, caused by calpain-mediated proteolysis, significantly reduced Cobl levels. In an apparently unique manner among excitotoxicity-affected proteins, this Cobl decline was rapidly restored by increased mRNA expression and Cobl then played a pivotal role in post-stroke dendritic arbor repair in peri-infarct areas. In Cobl KO mice, the dendritic repair window determined to span day 2-4 post-stroke in WT strikingly passed without any dendritic regrowth. Instead, Cobl KO penumbral neurons of the primary motor cortex continued to show the dendritic impairments caused by stroke. Our results thereby highlight a powerful post-stroke recovery process and identified causal molecular mechanisms critical during post-stroke repair.

Energy-Sensing Pathways in Ischemia: The Counterbalance Between AMPK and mTORC

2020 ◽  
Vol 25 (45) ◽  
pp. 4763-4770
Author(s):  
Angel Cespedes ◽  
Mario Villa ◽  
Irene Benito-Cuesta ◽  
Maria J. Perez-Alvarez ◽  
Lara Ordoñez ◽  
...  
Keyword(s):  
Blood Flow ◽  
Ischemic Stroke ◽  
Middle Cerebral Artery ◽  
Cause Of Death ◽  
Artery Occlusion ◽  
Brain Pathology ◽  
Common Cause ◽  
Specific Analysis ◽  
Energy Sensing ◽  
Cerebral Artery Occlusion

: Stroke is an important cause of death and disability, and it is the second leading cause of death worldwide. In humans, middle cerebral artery occlusion (MCAO) is the most common cause of ischemic stroke. The damage occurs due to the lack of nutrients and oxygen contributed by the blood flow. : The present review aims to analyze to what extent the lack of each of the elements of the system leads to damage and which mechanisms are unaffected by this deficiency. We believe that the specific analysis of the effect of lack of each component could lead to the emergence of new therapeutic targets for this important brain pathology.

LncRNAs a New Target for Post-Stroke Recovery

2020 ◽  
Vol 26 (26) ◽  
pp. 3115-3121
Author(s):  
Jun Yang ◽  
Jingjing Zhao ◽  
Xu Liu ◽  
Ruixia Zhu
Keyword(s):  
Ischemic Stroke ◽  
Microglial Activation ◽  
Vital Role ◽  
Stroke Recovery ◽  
Biological Processes ◽  
Current Development ◽  
Post Stroke ◽  
Cascade Processes ◽  
Non Coding Rnas ◽  
Neuron Injury

LncRNAs (long non-coding RNAs) are endogenous molecules, involved in complicated biological processes. Increasing evidence has shown that lncRNAs play a vital role in the post-stroke pathophysiology. Furthermore, several lncRNAs were reported to mediate ischemia cascade processes include apoptosis, bloodbrain barier breakdown, angiogenesis, microglial activation induced neuroinflammation which can cause neuron injury and influence neuron recovery after ischemic stroke. In our study, we first summarize current development about lncRNAs and post-stroke, focus on the regulatory roles of lncRNAs on pathophysiology after stroke. We also reviewed genetic variation in lncRNA associated with functional outcome after ischemic stroke. Additionally, lncRNA-based therapeutics offer promising strategies to decrease brain damage and promote neurological recovery following ischemic stroke. We believe that lncRNAs will become promising for the frontier strategies for IS and can open up a new path for the treatment of IS in the future.

Cerebrolysin and Aquaporin 4 Inhibition Improve Pathological and Motor Recovery after Ischemic Stroke

2018 ◽  
Vol 17 (4) ◽  
pp. 299-308 ◽  
Author(s):  
Bogdan Catalin ◽  
Otilia-Constantina Rogoveanu ◽  
Ionica Pirici ◽  
Tudor Adrian Balseanu ◽  
Adina Stan ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Vasogenic Edema ◽  
Artery Occlusion ◽  
Aquaporin 4 ◽  
Hypertonic Solution ◽  
Water Metabolism ◽  
Scar Region ◽  
Function Preservation ◽  
Neurotropic Factor ◽  
Cerebral Artery Occlusion

Background: Edema represents one of the earliest negative markers of survival and consecutive neurological deficit following stroke. The mixture of cellular and vasogenic edema makes treating this condition complicated, and to date, there is no pathogenically oriented drug treatment for edema, which leaves parenteral administration of a hypertonic solution as the only non-surgical alternative. Objective: New insights into water metabolism in the brain have opened the way for molecular targeted treatment, with aquaporin 4 channels (AQP4) taking center stage. We aimed here to assess the effect of inhibiting AQP4 together with the administration of a neurotropic factor (Cerebrolysin) in ischemic stroke. Methods: Using a permanent medial cerebral artery occlusion rat model, we administrated a single dose of the AQP4 inhibitor TGN-020 (100 mg/kg) at 15 minutes after ischemia followed by daily Cerebrolysin dosing (5ml/kg) for seven days. Rotarod motor testing and neuropathology examinations were next performed. Results: We showed first that the combination treatment animals have a better motor function preservation at seven days after permanent ischemia. We have also identified distinct cellular contributions that represent the bases of behavior testing, such as less astrocyte scarring and a larger neuronalsurvival phenotype rate in animals treated with both compounds than in animals treated with Cerebrolysin alone or untreated animals. Conclusion: Our data show that water diffusion inhibition and Cerebrolysin administration after focal ischemic stroke reduces infarct size, leading to a higher neuronal survival in the peri-core glial scar region.

scholarly journals Selective intra-carotid blood cooling in acute ischemic stroke: A safety and feasibility study in an ovine stroke model

2021 ◽  
pp. 0271678X2110249
Author(s):  
Giorgio FM Cattaneo ◽  
Andrea M Herrmann ◽  
Sebastian A Eiden ◽  
Manuela Wieser ◽  
Elias Kellner ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Carotid Artery ◽  
Acute Ischemic Stroke ◽  
Neurological Outcome ◽  
Artery Occlusion ◽  
Control Group ◽  
Stroke Model ◽  
Primary Endpoints ◽  
Neuroprotective Strategy ◽  
Vessel Patency

Selective therapeutic hypothermia (TH) showed promising preclinical results as a neuroprotective strategy in acute ischemic stroke. We aimed to assess safety and feasibility of an intracarotid cooling catheter conceived for fast and selective brain cooling during endovascular thrombectomy in an ovine stroke model. Transient middle cerebral artery occlusion (MCAO, 3 h) was performed in 20 sheep. In the hypothermia group (n = 10), selective TH was initiated 20 minutes before recanalization, and was maintained for another 3 h. In the normothermia control group (n = 10), a standard 8 French catheter was used instead. Primary endpoints were intranasal cooling performance (feasibility) plus vessel patency assessed by digital subtraction angiography and carotid artery wall integrity (histopathology, both safety). Secondary endpoints were neurological outcome and infarct volumes. Computed tomography perfusion demonstrated MCA territory hypoperfusion during MCAO in both groups. Intranasal temperature decreased by 1.1 °C/3.1 °C after 10/60 minutes in the TH group and 0.3 °C/0.4 °C in the normothermia group (p < 0.001). Carotid artery and branching vessel patency as well as carotid wall integrity was indifferent between groups. Infarct volumes (p = 0.74) and neurological outcome (p = 0.82) were similar in both groups. Selective TH was feasible and safe. However, a larger number of subjects might be required to demonstrate efficacy.

scholarly journals The Key Regulator of Necroptosis, RIP1 Kinase, Contributes to the Formation of Astrogliosis and Glial Scar in Ischemic Stroke

2021 ◽  
Author(s):  
Yong-Ming Zhu ◽  
Liang Lin ◽  
Chao Wei ◽  
Yi Guo ◽  
Yuan Qin ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Glucose Deprivation ◽  
Artery Occlusion ◽  
Glial Scar ◽  
Scar Formation ◽  
Reactive Astrocytes ◽  
Interacting Protein ◽  
Protein Levels ◽  
Endothelial Growth Factor ◽  
Cerebral Artery Occlusion

AbstractNecroptosis initiation relies on the receptor-interacting protein 1 kinase (RIP1K). We recently reported that genetic and pharmacological inhibition of RIP1K produces protection against ischemic stroke-induced astrocytic injury. However, the role of RIP1K in ischemic stroke-induced formation of astrogliosis and glial scar remains unknown. Here, in a transient middle cerebral artery occlusion (tMCAO) rat model and an oxygen and glucose deprivation and reoxygenation (OGD/Re)-induced astrocytic injury model, we show that RIP1K was significantly elevated in the reactive astrocytes. Knockdown of RIP1K or delayed administration of RIP1K inhibitor Nec-1 down-regulated the glial scar markers, improved ischemic stroke-induced necrotic morphology and neurologic deficits, and reduced the volume of brain atrophy. Moreover, knockdown of RIP1K attenuated astrocytic cell death and proliferation and promoted neuronal axonal generation in a neuron and astrocyte co-culture system. Both vascular endothelial growth factor D (VEGF-D) and its receptor VEGFR-3 were elevated in the reactive astrocytes; simultaneously, VEGF-D was increased in the medium of astrocytes exposed to OGD/Re. Knockdown of RIP1K down-regulated VEGF-D gene and protein levels in the reactive astrocytes. Treatment with 400 ng/ml recombinant VEGF-D induced the formation of glial scar; conversely, the inhibitor of VEGFR-3 suppressed OGD/Re-induced glial scar formation. RIP3K and MLKL may be involved in glial scar formation. Taken together, these results suggest that RIP1K participates in the formation of astrogliosis and glial scar via impairment of normal astrocyte responses and enhancing the astrocytic VEGF-D/VEGFR-3 signaling pathways. Inhibition of RIP1K promotes the brain functional recovery partially via suppressing the formation of astrogliosis and glial scar. Graphical Abstract

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