Selective cerebral cooling for acute ischemic stroke

The neurophysiological effect of mild hypothermia in gyrencephalic brains submitted to ischemic stroke and spreading depolarizations

Objective

Characterize the neurophysiological effects of mild hypothermia on stroke and spreading depolarizations (SDs) in gyrencephalic brains.

Methods

Left middle cerebral arteries (MCAs) of six hypothermic and six normothermic pigs were permanently occluded (MCAo). Hypothermia began 1 h after MCAo and continued throughout the experiment. ECoG signals from both frontoparietal cortices were recorded. Five-minute ECoG epochs were collected 5 min before, at 5 min, 4, 8, 12, and 16 h after MCAo, and before, during, and after SDs. Power spectra were decomposed into fast (alpha, beta, and gamma) and slow (delta and theta) frequency bands.

Results

In the vascular insulted hemisphere under normothermia, electrodes near the ischemic core exhibited power decay across all frequency bands at 5 min and the 4th hour after MCAo. The same pattern was registered in the two furthest electrodes at the 12th and 16th hour. When mild hypothermia was applied in the vascular insulted hemispheres, the power decay was generalized and seen even in electrodes with uncompromised blood flow. During SD analysis, hypothermia maintained increased delta and beta power during the three phases of SDs in the furthest electrode from the ischemic core, followed by the second furthest and third electrode in the beta band during preSD and postSD segments. However, in hypothermic conditions, the third electrode showed lower delta, theta, and alpha power.

Conclusion

Mild hypothermia attenuates all frequency bands in the vascularly compromised hemisphere, irrespective of the cortical location. During SD formation, it preserves power spectra more significantly in electrodes further from the ischemic core.

Mild hypothermia reduces spreading depolarizations and infarct size in a swine model

Spreading depolarizations (SDs) have been linked to infarct volume expansion following ischemic stroke. Therapeutic hypothermia provides a neuroprotective effect after ischemic stroke. This study aimed to evaluate the effect of hypothermia on the propagation of SDs and infarct volume in an ischemic swine model. Through left orbital exenteration, middle cerebral arteries were surgically occluded (MCAo) in 16 swine. Extensive craniotomy and durotomy were performed. Six hypothermic and five normothermic animals were included in the analysis. An intracranial temperature probe was placed right frontal subdural. One hour after ischemic onset, mild hypothermia was induced and eighteen hours of electrocorticographic (ECoG) and intrinsic optical signal (IOS) recordings were acquired. Postmortem, 4 mm-thick slices were stained with 2,3,5-triphenyltetrazolium chloride to estimate the infarct volume. Compared to normothermia (36.4 ± 0.4°C), hypothermia (32.3 ± 0.2°C) significantly reduced the frequency and expansion of SDs (ECoG: 3.5 ± 2.1, 73.2 ± 5.2% vs. 1.0 ± 0.7, 41.9 ± 21.8%; IOS 3.9 ± 0.4, 87.6 ± 12.0% vs. 1.4 ± 0.7, 67.7 ± 8.3%, respectively). Further, infarct volume among hypothermic animals (23.2 ± 1.8% vs. 32.4 ± 2.5%) was significantly reduced. Therapeutic hypothermia reduces infarct volume and the frequency and expansion of SDs following cerebral ischemia.

The neurovascular unit and systemic biology in stroke - implications for translation and treatment

Ischaemic stroke is a leading cause of disability and death for which no acute treatments exist beyond recanalization. The development of novel therapies has been repeatedly hindered by translational failures that have changed the way we think about tissue damage after stroke. What was initially a neuron-centric view has been replaced with the concept of the neurovascular unit (NVU), which encompasses neuronal, glial and vascular compartments, and the biphasic nature of neural-glial-vascular signalling. However, it is now clear that the brain is not the private niche it was traditionally thought to be and that the NVU interacts bidirectionally with systemic biology, such as systemic metabolism, the peripheral immune system and the gut microbiota. Furthermore, these interactions are profoundly modified by internal and external factors, such as ageing, temperature and day-night cycles. In this Review, we propose an extension of the concept of the NVU to include its dynamic interactions with systemic biology. We anticipate that this integrated view will lead to the identification of novel mechanisms of stroke pathophysiology, potentially explain previous translational failures, and improve stroke care by identifying new biomarkers of and treatment targets in stroke.

Protective Properties of the Extract of Chrysanthemum on Patients with Ischemic Stroke

Investigation of the protective effect of chrysanthemum extract in ischemic strokes patients is among the challenging issues with the traditional hospital system in general and smart technology-based hospitals in particular. In this study, we have evaluated the protective effect of chrysanthemum extract on patients with ischemic stroke by detecting the severity of stroke, neuronal indexes, and oxidative stress biomarkers. For this purpose, forty-six patients with ischemic stroke were randomly divided into the control group (n = 30) and chrysanthemum group (n = 30). The control group received standard stroke treatment, and the chrysanthemum group was treated with chrysanthemum extract 400 mg/day (200 mg/day, twice/day) on the basis of standard treatment. The groups were compared the effect of saffron capsules using the National Institute of Health Stoke Scale (NIHSS), serum neuron specific enolase (NSE), S100, brain-derived neurotrophic factor (BDNF), malondialdehyde (MDA), Su-peroxide dismutase (SOD), and total antioxidant capacity (TAC ) levels, at the time of first day and fourth day after treatment. On the first day after treatment, there was no significant difference in the NIHSS score, serum NSE, S100, BDNF, MDA, SOD, and TAC levels between the chrysanthemum group and the control group (P > 0.05). On the fourth day after treatment, the NIHSS, serum NSE, S100, and MDA levels were significantly reduced in the chrysanthemum group compared to the control group, while the BDNF, SOD, and TAC levels were higher (P < 0.05). In addition, compared to the levels on the first day, the NIHSS, serum NSE, S100, and MDA levels were significantly reduced, and the BDNF, SOD, and TAC levels were increased in the chrysanthemum group on the fourth day (P < 0.05). Chrysanthemum extract has the effects of scavenging oxygen free radicals and antioxidation and has a neuroprotective effect on ischemic stroke patients.

Neuroprotection in Acute Ischemic Stroke: A Brief Review

The goal of effective neuroprotection in acute ischemic stroke remains elusive. Despite decades of experimental preclinical and clinical experience with innumerable agents, no strategy has proven to be beneficial in humans. As endovascular therapies mature and approach the limits of speed and efficacy, neuroprotection will become the next frontier of acute stroke care. This review will briefly summarize the history, preclinical and clinical triumphs and failures, and future directions of cerebral neuroprotection.

Selective intra-arterial brain cooling induces cerebral protection against ischemia/reperfusion injury through SENP1-Sirt3 signaling

BACKGROUND

Although it is well known that selective intra-arterial cooling (SI-AC) elicits cerebral protection against ischemia/reperfusion (I/R) injury, the underlying mechanism remains unclear. This study aimed to determine whether SI-AC can protect against cerebral I/R injury by inhibiting oxidative stress and mitochondrial dysfunction through regulation of Sirt3 deSUMOylation via SENP1.

METHODS

All mice were subjected to 2 h of cerebral ischemia followed by 24 h of reperfusion. SI-AC treatment was performed by infusion with cold saline (10 °C, 20 mL/kg) for 15 min through a microcatheter placed in the internal carotid artery immediately before reperfusion. The infarct volume, survival rate, neurological deficit scores, behavioral parameters, histopathology findings, and apoptosis were assessed. HT22 cells were subjected to 2 h of oxygen and sugar deprivation (OGD) and 22 h of reoxygenation. HA-SUMO1, Flag-Sirt3, a Sirt3 mutation plasmid (Flag-Sirt3 K288R), His-SENP1, and SENP1 small interfering RNA were transfected into HT22 cells 48 h before OGD. Apoptosis-related proteins were analyzed by western blotting. SUMOylation of Sirt3, acetylation of cyclooxygenase 1 (COX1), superoxide dismutase 2 (SOD2), and isocitrate dehydrogenase 2 (IDH2), the activities of COX1, SOD2, and IDH2, oxidative stress, and mitochondrial dysfunction were evaluated.

RESULTS

Compared with the I/R group, SI-AC decreased cerebral infarct volume and neurological deficit scores and increased motor coordination, exploratory behavior, and memory. Hematoxylin and eosin and Nissl staining showed that SI-CA decreased karyopyknosis, nuclear fragmentation, and nucleolysis, increased neuron density, and decreased the cell apoptosis rate. In addition, Sirt3 was revealed as a target protein of SUMO1. SI-AC attenuated cerebral I/R injury through Sirt3 deSUMOylation via SENP1.

CONCLUSIONS

SENP1-mediated deSUMOylation of Sirt3 plays an essential role in SI-AC-induced cerebral protection against I/R injury. Our findings provide a promising therapeutic approach for treatment of acute cerebral I/R injury.