Ischemic Area Research Articles

Effect of serum from patients with ST-segment elevation myocardial infarction on endothelial cells

Introduction and objectivesClinical and experimental studies have shown that, in patients with reperfused ST-segment elevation myocardial infarction (STEMI), abnormalities in the endothelial monolayer are initiated during ischemia but rapidly intensify upon restoration of blood perfusion to the ischemic area. We aimed to evaluate the effect of serum isolated after revascularization from STEMI patients on the degree of endothelial permeability in vitro, by promoting endothelial cell apoptosis and necrosis in vitro. We also investigated the association between the percentage of serum-induced endothelial cell apoptosis or necrosis in vitro and the extent of cardiovascular magnetic resonance (CMR)-derived parameters of reperfusion injury (edema, hemorrhage, and microvascular obstruction). MethodsHuman coronary artery endothelial cells were incubated with serum isolated 24hours after revascularization from 43 STEMI patients who underwent CMR and 14 control participants. We assessed the effect of STEMI serum on activation of apoptosis and necrosis, as well as on the permeability and structure of the endothelial monolayer. ResultsSerum from STEMI patients increased apoptosis (P <.01) and necrosis (P <.05) in human coronary artery endothelial cells and caused increased permeability of the endothelial monolayer in vitro (P <.01), due to enlarged intercellular spaces (P <.05 vs control in all cases). Higher serum-induced necrosis was associated with greater endothelial permeability in vitro (P <.05) and with more extensive CMR-derived indices of reperfusion injury and infarct size. ConclusionsPostreperfusion serum activates necrosis and apoptosis in endothelial cells and increases the degree of endothelial permeability in vitro. The more potent the necrosis-triggering effect of serum, the more deleterious the consequences in terms of the resulting cardiac structure.

Second-generation extracellular matrix patch for epicardial infarct repair

Current myocardial infarction treatments focus on improving hemodynamics rather than addressing the problem of lost myocardium impairing left ventricular function. Epicardial infarct repair with a bioactive patch placed on the ischemic area is an emerging approach to promote endogenous myocardial repair. We report the use of a second-generation CorMatrix-extracellular matrix (ECM) patch as an adjunct to surgical revascularization in treating a young patient with diffuse, multivessel coronary artery disease unamenable to PCI and a large anterior myocardial infarction. The progressive myocardial scar shrinkage and increase in left ventricular ejection fraction from 10 to 51% are generally not observed with surgical revascularization therapy alone, suggesting this new patch has adjunctive potential to current revascularization therapy.

Secondary neurodegeneration following Stroke: what can blood biomarkers tell us?

Stroke is one of the leading causes of death and the primary source of disability in adults, resulting in neuronal necrosis of ischemic areas, and in possible secondary degeneration of regions surrounding or distant to the initial damaged area. Secondary neurodegeneration (SNDG) following stroke has been shown to have different pathogenetic origins including inflammation, neurovascular response and cytotoxicity, but can be associated also to regenerative processes. Aside from focal neuronal loss, ipsilateral and contralateral effects distal to the lesion site, disruptions of global functional connectivity and a transcallosal diaschisis have been reported in the chronic stages after stroke. Furthermore, SNDG can be observed in different areas not directly connected to the primary lesion, such as thalamus, hippocampus, amygdala, substantia nigra, corpus callosum, bilateral inferior fronto-occipital fasciculus and superior longitudinal fasciculus, which can be highlighted by neuroimaging techniques. Although the clinical relevance of SNDG following stroke has not been well understood, the identification of specific biomarkers that reflect the brain response to the damage, is of paramount importance to investigate in vivo the different phases of stroke. Actually, brain-derived markers, particularly neurofilament light chain, tau protein, S100b, in post-stroke patients have yielded promising results. This review focuses on cerebral morphological modifications occurring after a stroke, on associated cellular and molecular changes and on state-of-the-art of biomarkers in acute and chronic phase. Finally, we discuss new perspectives regarding the implementation of blood-based biomarkers in clinical practice to improve the rehabilitation approaches and post stroke recovery.

Wallenberg syndrome in a patient after pulmonary resection: a case report

BackgroundCerebral infarction after pulmonary resection is a minor but critical complication. We report a rare case of postoperative complication of Wallenberg syndrome caused by cerebral infarction in the posterior inferior cerebral artery after the left upper lobectomy.Case presentationA 72-year-old man developed cerebral infarction 2 days after a left upper lobectomy for lung cancer. Magnetic resonance imaging indicated right vertebral artery occlusion following an early ischemic area on the right lateral side of the medulla oblongata and cerebellum. Contrast-enhanced computed tomography revealed no thrombus in the left superior pulmonary vein stump. The patient was diagnosed with Wallenberg syndrome, and prompt anticoagulation therapy was initiated. The patient was discharged and transferred to another hospital for rehabilitation on postoperative day 16.ConclusionsWe present a rare case of Wallenberg syndrome occurring in the posterior inferior cerebral artery area due to vertebral artery occlusion after lobectomy. Because cerebral infarction of the posterior circulation has many similar symptoms due to the side effects of anesthetic drugs, careful physical examination is required to determine Wallenberg syndrome.

Acute coronary syndrome with simultaneous two-vessel occlusion De Winter ST-segment depression or reciprocal change?

We discuss a case of acute coronary syndrome (ACS) with simultaneous two-vessel occlusions in a man in his 20s. The serial electrocardiograms (ECG) showed very early dynamic changes of ST-T configuration resulting from ischemic zone depth or area between anterior wall versus inferior wall. The upsloping ST depression along with tall tentorial T waves in the precordial leads, as shown in the index ECG, raises the possibilities of a de Winter pattern. The retrospective assessment of the index ECG identified prominent T waves and a mild degree of ST-segment elevations in the inferior leads, given the electrocardiographic findings previously recorded at his workplace medical examination obtained at a later date. If the subtle ST-segment elevations in leads II, III, and aVF and the tall T waves were not overlooked in the index ECG, the probability of reciprocal ST-segment depressions in the precordial leads should also be taken into account. We recognize our ECG findings as intriguing ST-T deviation patterns that can change depending on the time sequence and anatomical dominancy of two infarct-related arteries. We finally suggest physicians should bear in mind the possibility of simultaneous multiple vessel occlusions when they encounter ACS patients with hemodynamic instability as in this present case

Regeneration of the cerebral cortex by direct chemical reprogramming of macrophages into neuronal cells in acute ischemic stroke.

Theoretically, direct chemical reprogramming of somatic cells into neurons in the infarct area represents a promising regenerative therapy for ischemic stroke. Previous studies have reported that human fibroblasts and astrocytes transdifferentiate into neuronal cells in the presence of small molecules without introducing ectopic transgenes. However, the optimal combination of small molecules for the transdifferentiation of macrophages into neurons has not yet been determined. The authors hypothesized that a combination of small molecules could induce the transdifferentiation of monocyte-derived macrophages into neurons and that the administration of this combination may be a regenerative therapy for ischemic stroke because monocytes and macrophages are directly involved in the ischemic area. Transcriptomes and morphologies of the cells were compared before and after stimulation using RNA sequencing and immunofluorescence staining. Microscopic analyses were also performed to identify cell markers and evaluate functional recovery by blinded examination following the administration of small molecules after ischemic stroke in CB-17 mice. In this study, an essential combination of six small molecules [CHIR99021, Dorsomorphin, Forskolin, isoxazole-9 (ISX-9), Y27632, and DB2313] that transdifferentiated monocyte-derived macrophages into neurons in vitro was identified. Moreover, administration of six small molecules after cerebral ischemia in model animals generated a new neuronal layer in the infarct cortex by converting macrophages into neuronal cells, ultimately improving neurological function. These results suggest that altering the transdifferentiation of monocyte-derived macrophages by the small molecules to adjust their adaptive response will facilitate the development of regenerative therapies for ischemic stroke.

Microglia Negatively Regulate the Proliferation and Neuronal Differentiation of Neural Stem/Progenitor Cells Isolated from Poststroke Mouse Brains.

We previously demonstrated that neural stem/progenitor cells (NSPCs) were induced within and around the ischemic areas in a mouse model of ischemic stroke. These injury/ischemia-induced NSPCs (iNSPCs) differentiated to electrophysiologically functional neurons in vitro, indicating the presence of a self-repair system following injury. However, during the healing process after stroke, ischemic areas were gradually occupied by inflammatory cells, mainly microglial cells/macrophages (MGs/MΦs), and neurogenesis rarely occurred within and around the ischemic areas. Therefore, to achieve neural regeneration by utilizing endogenous iNSPCs, regulation of MGs/MΦs after an ischemic stroke might be necessary. To test this hypothesis, we used iNSPCs isolated from the ischemic areas after a stroke in our mouse model to investigate the role of MGs/MΦs in iNSPC regulation. In coculture experiments, we show that the presence of MGs/MΦs significantly reduces not only the proliferation but also the differentiation of iNSPCs toward neuronal cells, thereby preventing neurogenesis. These effects, however, are mitigated by MG/MΦ depletion using clodronate encapsulated in liposomes. Additionally, gene ontology analysis reveals that proliferation and neuronal differentiation are negatively regulated in iNSPCs cocultured with MGs/MΦs. These results indicate that MGs/MΦs negatively impact neurogenesis via iNSPCs, suggesting that the regulation of MGs/MΦs is essential to achieve iNSPC-based neural regeneration following an ischemic stroke.

Ipsilateral and contralateral carotid stenosis contribute to the outcome of reperfusion treatment for ischemic stroke.

Ipsilateral and contralateral carotid stenosis (ICS, CCS) influence acute ischemic stroke (AIS) severity and prognosis. Few data are available about their impact on reperfusion therapies efficacy. Aim of this study was to evaluate the impact of ICS and CCS on the effect of intravenous thrombolysis (IT), mechanical thrombectomy (MT) or both and of antiplatelet therapy (AT). We enrolled all the consecutive patients admitted for AIS to our stroke unit and submitted to IT, MT, IT+MT, or AT. We established the presence of a significant ICS or CCS (≥70%) by ultrasound examination or brain angio-CT, or MRI. Clinical and instrumental information were collected; delta National Institutes of Health Stroke Scale (NIHSS) from pre-treatment to patients' discharge was employed as the main outcome measure. In total, 460 subjects were enrolled, 86 with ICS and 38 with CCS. We observed a significant linear trend of delta (NIHSS) between carotid stenosis categories for patients undergoing IT (p = 0.011), MT (p = 0.046), and MT+IT (p = 0.040), but no significant trend among subjects receiving no reperfusion treatments was observed (p = 0.174). According to our findings, ICS and CCS negatively influence AIS patients' outcome treated by interventional therapies. ICS might exert an unfavorable effect both by cerebral hypoperfusion and by continuous microembolization toward ischemic area, while CCS is probable involved in reducing the collateral circles effectiveness. The importance of early carotid stenosis detection and treatment should then be reevaluated not only to manage the prevention approaches but also to obtain insights about post-stroke treatment strategies efficacy.

Real-time laser speckle contrast imaging measurement during normothermic machine perfusion in pretransplant kidney assessment.

Normothermic machine perfusion (NMP) provides a platform for pre-transplant kidney quality assessment that is essential for the use of marginal donor kidneys. Laser speckle contrast imaging (LSCI) presents distinct advantages as a real-time and noncontact imaging technique for measuring microcirculation. In this study, we aimed to assess the value of LSCI in visualizing renal cortical perfusion and investigate the additional value of dual-side LSCI measurements compared to single aspect measurement during NMP. Porcine kidneys were obtained from a slaughterhouse and then underwent NMP. LSCI was used to measure one-sided cortical perfusion in the first 100 min of NMP. Thereafter, the inferior renal artery branch was occluded to induce partial ischemia and LSCI measurements on both ventral and dorsal sides were performed. LSCI fluxes correlated linearly with the renal blood flow (R2 = 0.90, p < 0.001). After renal artery branch occlusion, absence of renal cortical perfusion could be visualized and semiquantified by LSCI. The overall ischemic area percentage of the ventral and dorsal sides was comparable (medianinterquartile range[IQR], 38 [24-43]% vs. 29 [17-46]%, p = 0.43), but heterogenous patterns between the two aspects were observed. There was a significant difference in oxygen consumption (mean ± standard deviation [SD], 2.57 ± 0.63 vs. 1.83 ± 0.49 mLO2 /min/100 g, p < 0.001), urine output (median [IQR], 1.3 [1.1-1.7] vs. 0.8 [0.6-1.3] mL/min, p < 0.05), lactate dehydrogenase (mean ± SD, 768 ± 370 vs. 905 ± 401 U/L, p < 0.05) and AST (mean ± SD, 352 ± 285 vs. 462 ± 383 U/L, p < 0.01) before and after renal artery occlusion, while no significant difference was found in creatinine clearance, fractional excretion of sodium, total sodium reabsorption and histological damage. LSCI fluxes correlated linearly with renal blood flow during NMP. Renal cortical microcirculation and absent perfusion can be visualized and semiquantified by LSCI. It provides a relative understanding of perfusion levels, allowing for a qualitative comparison between regions in the kidney. Dual-side LSCI measurements are of added value compared to single aspect measurement and renal function markers.

The association between cortical venous outflow and futile recanalization in patients with acute ischemic stroke due to large vessel occlusion in the anterior circulation

Objective: To explore the association of baseline venous outflow (VO) profile with futile recanalization in patients with acute ischemic stroke due to large vessel occlusion in the anterior circulation. Methods: The clinical and imaging data of patients presented with large vessel occlusion in the anterior circulation and underwent emergency endovascular treatment at Huashan Hospital from March 2015 to December 2021 were retrospectively included in the study. All patients were assessed by the National Institutes of Health Stroke Scale (NIHSS) at baseline.Baseline VO profile was determined by a 0-6 semi-quantitative scoring system which assessed opacification of the ipsilateral superficial middle cerebral vein, vein of Labbé and vein of Trolard on single-phase CT angiography (CTA) images. A 90-day telephone follow-up was performed and functional outcome was evaluated by 90 d modified Rankin scale (mRS). Successful recanalization of the occluded artery, defined as final modified Thrombolysis in Cerebral Infarction scale (mTICI) 2b-3, was considered to be futile if patients failed to achieve functional independence (90 d mRS 0-2). Univariate analysis and receiver operating characteristic (ROC) curve analysis were used to explore the optimal cutoff predicting functional indendence. The associations between cortical VO in ischemic area and futile recanalization were evaluated using binary logistic regression analysis and backward linear regression based on Akaike information criterion (AIC). Results: A total of 150 patients met the inclusion criteria, with 92 males (61.3%) and 58 females (38.7%). The median age [M(Q1, Q3)]was 71 (61, 78) years and the median baseline National Institute of Health Stroke Scale (NIHSS) score [M(Q1, Q3)]was 15 (11, 18). Univariate logistic regression analysis showed that baseline VO was associated with 90-day functional independence (OR=1.587, 95%CI: 1.185-2.1873). After classifying VO into two categories based on the receiver operating characteristic (ROC) curve, VO≥4 showed an independent association with functional independence (OR=5.133, 95%CI: 1.530-9.361) after adjusting for age, baseline glucose, NIHSS score, baseline infarct core volume, modified Tan (mTan) score, hypoperfusion intensity ratio (HIR), etiological classification, recanalization, presence of any hemorrhagic transformation and final infarct volume. Futile recanalization was observed in 44 (48.4%) of the 91 patients who achieved successful recanalization. Stepwise logistic regression revealed that VO≥4 was an independent protective factor for futile recanalization (OR=0.234, 95%CI: 0.054-0.878). Moreover, in patients with mTICI 2c-3, VO≥4 showed a stronger association with futile recanalization (OR=0.018, 95%CI: 0-0.255). Conclusion: A favorable VO profile at onset protects against futile recanalization in patients with large vessel occlusion in the anterior circulation, and provides a simple and feasible auxiliary method for predicting the prognosis of endovascular therapy in such patients.

Astrocyte-neuron lactate shuttle plays a pivotal role in sensory-based neuroprotection in a rat model of permanent middle cerebral artery occlusion

We have previously demonstrated protection from impending cortical ischemic stroke is achievable by sensory stimulation of the ischemic area in an adult rat model of permanent middle cerebral artery occlusion (pMCAo). We have further demonstrated that a major underpinning mechanism that is necessary for such protection is the system of collaterals among cerebral arteries that results in reperfusion of the MCA ischemic territory. However, since such collateral flow is weak, it may be necessary but not sufficient for protection and therefore we sought other complementary mechanisms that contribute to sensory-based protection. We hypothesized that astrocytes-neuron lactate shuttle (ANLS) activation could be another potential underpinning mechanism that complements collateral flow in the protection process. Supporting our hypothesis, using functional imaging, pharmacological treatments, and postmortem histology, we showed that ANLS played a pivotal role in sensory stimulation-based protection of cortex and therefore serves as the other supporting mechanism underpinning the protection process.

Diabetic microaneurysms detected by fluorescein angiography spatially correlate with regions of macular ischemia delineated by optical coherence tomography angiography.

To characterize the relationship between diabetic macular ischemia (DMI) delineated by optical coherence tomography angiography (OCTA) and microaneurysms (MAs) identified by fundus fluorescein angiography (FFA). Patients with diabetic retinopathy (DR) who underwent OCTA and FFA were retrospectively identified. FFA images were cropped and aligned with their respective OCTA images using i2k Align Retina software (Dual-Align, Clifton Park, NY, USA). Foveal avascular zone (FAZ) and ischemic areas were manually delineated on OCTA images, and MAs were marked on the corresponding FFA images before overlaying paired scans for analysis (ImageJ; National Institutes of Health, Bethesda, MD, USA). Twenty-eight eyes of 20 patients were included. The average number of MAs identified in cropped FFA images was 127 ± 42. More DMI was noted in the superficial capillary plexus (SCP; 36 ± 13%) compared to the deep capillary plexus (DCP; 28 ± 14%, P < 0.001). Similarly, more MAs were associated with ischemic areas in SCP compared to DCP (92.0 ± 35.0 vs. 76.8 ± 36.5, P < 0.001). Most MAs bordered ischemic areas; fewer than 10% localized inside these regions. As DMI area increased, so did associated MAs (SCP: r = 0.695, P < 0.001; DCP: r = 0.726, P < 0.001). Density of MAs surrounding FAZ (7.7 ± 6.0 MAs/mm2) was similar to other DMI areas (SCP: 7.0 ± 4.0 MAs/mm2, P = 0.478; DCP: 9.2 ± 10.9 MAs/mm2, P = 0.394). MAs identified in FFA strongly associate with, and border areas of, DMI delineated by OCTA. Although more MAs are localized to SCP ischemia, the concentration of MAs associated with DCP ischemia is greater. By contrast, few MAs are present inside low-flow regions, likely because capillary loss is associated with their regression.

Brain computed tomography in centenarians presenting to the emergency department: is age an indication to CT scan?

This study aimed to explore the relationship between admission complaints and brain computed tomography (CT) examinations. Also, we evaluated the relationship between age and CT scan results in centenarians admitted to the emergency department for non-traumatic reasons. This study was a retrospective analysis of patients aged 100 years and older who presented to the tertiary hospital emergency department for non-traumatic reasons between 2012 and 2021. Demographic characteristics, admission complaints, and indications used for brain CT were evaluated. The Fazekas grade and Evans index were compared with a younger population aged 85-90 years. Brain CT was ordered in 41.1% (n: 15/34) of the patients due to their atypical symptoms. While no acute pathology was found in the CT scans, 23.5% of the patients had an incidental intracranial mass and/or chronic ischemic areas. When the leukoencephalopathy findings of the centenarian patients were compared to the patients aged 85-90, it was determined that the Fazekas grade increased with age (p = 0.002). Concerning the ventricle diameter, there was a significant difference between the two groups (p = 0.017), with larger values detected in the 85-90 years group. Although no acute pathology was found in the brain CT scans of the centenarian patients who presented to the emergency department for any reason other than trauma, CT plays a fundamental role in determining emergency diagnosis and management strategies in patients presenting with atypical symptoms. While the degree of leukoencephalopathy increased with age, the ventricle diameter was significantly larger in the younger age group than in the centenarian patients.

Persulfidation of mitoKv7.4 channels contributes to the cardioprotective effects of the H2S-donor Erucin against ischemia/reperfusion injury

BackgroundHydrogen sulfide (H2S) is a gasotransmitter deeply involved in cardiovascular homeostasis and implicated in the myocardial protection against ischemia/reperfusion. The post-translational persulfidation of cysteine residues has been identified as the mechanism through which H2S regulates a plethora of biological targets. Erucin (ERU) is an isothiocyanate produced upon hydrolysis of the glucosinolate glucoerucin, presents in edible plants of Brassicaceae family, such as Eruca sativa Mill., and it has emerged as a slow and long-lasting H2S-donor. AimIn this study the cardioprotective profile of ERU has been investigated and the action mechanism explored, focusing on the possible role of the recently identified mitochondrial Kv7.4 (mitoKv7.4) potassium channels. ResultsInterestingly, ERU showed to release H2S and concentration-dependently protected H9c2 cells against H2O2-induced oxidative damage. Moreover, in in vivo model of myocardial infarct ERU showed protective effects, reducing the extension of ischemic area, the levels of troponin I and increasing the amount of total AnxA1, as well as co-related inflammatory outcomes. Conversely, the pre-treatment with XE991, a blocker of Kv7.4 channels, abolished them. In isolated cardiac mitochondria ERU exhibited the typical profile of a mitochondrial potassium channels opener, in particular, this isothiocyanate produced a mild depolarization of mitochondrial membrane potential, a reduction of calcium accumulation into the matrix and finally a flow of potassium ions. Finally, mitoKv7.4 channels were persulfidated in ERU-treated mitochondria. ConclusionsERU modulates the cardiac mitoKv7.4 channels and this mechanism may be relevant for cardioprotective effects.

Tricellulin, α-Catenin and Microfibrillar-Associated Protein 5 Exhibit Concomitantly Altered Immunosignals along with Vascular, Extracellular and Cytoskeletal Elements after Experimental Focal Cerebral Ischemia.

Along with initiatives to understand the pathophysiology of stroke in detail and to identify neuroprotective targets, cell-stabilizing elements have gained increasing attention. Although cell culture experiments have indicated that tricellulin, α-catenin and microfibrillar-associated protein 5 (MFAP5) contribute to cellular integrity, these elements have not yet been investigated in the ischemic brain. Applying immunofluorescence labeling, this study explored tricellulin, MFAP5 and α-catenin in non-ischemic and ischemic brain areas of mice (24, 4 h of ischemia) and rats (4 h of ischemia), along with collagen IV and fibronectin as vascular and extracellular matrix constituents and microtubule-associated protein 2 (MAP2) and neurofilament light chain (NF-L) as cytoskeletal elements. Immunosignals of tricellulin and notably MFAP5 partially appeared in a fiber-like pattern, and α-catenin appeared more in a dotted pattern. Regional associations with vascular and extracellular constituents were found for tricellulin and α-catenin, particularly in ischemic areas. Due to ischemia, signals of tricellulin, MFAP5 and α-catenin decreased concomitantly with MAP2 and NF-L, whereby MFAP5 provided the most sensitive reaction. For the first time, this study demonstrated ischemia-related alterations in tricellulin, MFAP5 and α-catenin along with the vasculature, extracellular matrix and cytoskeleton. Confirmatory studies are needed, also exploring their role in cellular integrity and the potential for neuroprotective approaches in stroke.

Neuroprotective Effects of Tryptanthrin-6-Oxime in a Rat Model of Transient Focal Cerebral Ischemia.

The activation of c-Jun N-terminal kinase (JNK) plays an important role in stroke outcomes. Tryptanthrin-6-oxime (TRYP-Ox) is reported to have high affinity for JNK and anti-inflammatory activity and may be of interest as a promising neuroprotective agent. The aim of this study was to investigate the neuroprotective effects of TRYP-Ox in a rat model of transient focal cerebral ischemia (FCI), which involved intraluminal occlusion of the left middle cerebral artery (MCA) for 1 h. Animals in the experimental group were administered intraperitoneal injections of TRYP-Ox 30 min before reperfusion and 23 and 47 h after FCI. Neurological status was assessed 4, 24, and 48 h following FCI onset. Treatment with 5 and 10 mg/kg of TRYP-Ox decreased mean scores of neurological deficits by 35-49 and 46-67% at 24 and 48 h, respectively. At these doses, TRYP-Ox decreased the infarction size by 28-31% at 48 h after FCI. TRYP-Ox (10 mg/kg) reduced the content of interleukin (IL) 1β and tumor necrosis factor (TNF) in the ischemic core area of the MCA region by 33% and 38%, respectively, and attenuated cerebral edema by 11% in the left hemisphere, which was affected by infarction, and by 6% in the right, contralateral hemisphere 24 h after FCI. TRYP-Ox reduced c-Jun phosphorylation in the MCA pool at 1 h after reperfusion. TRYP-Ox was predicted to have high blood-brain barrier permeability using various calculated descriptors and binary classification trees. Indeed, reactive oxidant production was significantly lower in the brain homogenates from rats treated with TRYP-Ox versus that in control animals. Our data suggest that the neuroprotective activity of TRYP-Ox may be due to the ability of this compound to inhibit JNK and exhibit anti-inflammatory and antioxidant activity. Thus, TRYP-Ox may be considered a promising neuroprotective agent that potentially could be used for the development of new treatment strategies in cerebral ischemia.

Intercellular mitochondrial component transfer triggers ischemic cardiac fibrosis

Myocardial fibrosis is the villain of sudden cardiac death. Myocardial ischemia/reperfusion (MI/R) injury induces cardiomyocyte damage or even death, which in turn stimulates fibroblast activation and fibrosis, but the intercellular communication mechanism remains unknown. Recent studies have shown that small extracellular vesicles (sEVs) significantly contribute to intercellular communication. Whether and how sEV might mediate post-MI/R cardiomyocyte/fibroblasts communication remain unknown. Here, in vivo and in vitro MI/R models were established. We demonstrate that sEVs derived from cardiomyocyte (Myo-sEVs) carry mitochondrial components, which enter fibroblasts to initiate myocardial fibrosis. Based on bioinformatics screening and experimental verification, the activating molecule in Beclin1-regulated autophagy protein 1 (autophagy/beclin-1 regulator 1, Ambra1) was found to be a critical component of these sEV and might be a new marker for Myo-sEVs. Interestingly, release of Ambra1+-Myo-sEVs was caused by secretory rather than canonical autophagy after MI/R injury and thereby escaped degradation. In ischemic and peripheral areas, Ambra1+-Myo-sEVs were internalized by fibroblasts, and the delivered mtDNA components to activate the fibroblast cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway to promote fibroblast activation and proliferation. In addition, our data show that Ambra1 is expressed on the EV surface and cardiac-specific Ambra1 down regulation inhibits the Ambra1+-Myo-sEVs release and fibroblast uptake, effectively inhibiting ischemic myocardial fibrosis. This finding newly provides the evidence that myocardial secretory autophagy plays a role in intercellular communication during cardiac fibrosis. Ambra1 is a newly characterized molecule with bioactivity and might be a marker for Myo-sEVs, providing new therapeutic targets for cardiac remodeling.

Study of morphological transformation and features of vascular blood flow of the wall of the small and large intestine in the simulation of ischemia in the experiment

Introduction. Ischemia of the small and large intestine of various degree was simulated in 45 sexually mature male rats of the Wistar line weighing 150-200 g on the basis of the Department of Experimental Medicine with vivarium at Privolzhsky Research Medical University. Аim. To present in an experiment the effect of different degrees of occlusive ischemia on the morphological transformation of the intestinal wall and the level of changes in blood flow.Materials and methods. The anesthetized animals underwent a median laparotomy with subsequent differentiation of the intestinal divisions: the jejunal section was selected in the small intestine, the ascending section was selected in the large intestine. With the help of a nylon thread (5-0), the blood supplying arcades of these zones were ligated and further exposed for 40, 60 and 120 minutes. During the indicated periods of ischemia, the average rate of blood supply in capillary microvessels located at a depth of 0.5-1.0 mm was estimated in relative units on 1.0 mm2-area (LACC-02, NPP Lazma, Russia). After the assessment of vascular blood flow was completed, ischemic intestinal areas were sampled for morphological examination. The study results were processed using Excel application and STADIA statistical package. Results. In the course of study, the authors registered clear relationships between blood flow parameters in different parts of the intestine and the duration of ischemia. Local trophic disturbance was combined with a transformation in the histoarchitectonics of the intestinal wall. It is noted that adaptive-regenerative mechanisms provide tissue stress reduction in 120 min. due to compensatory mechanisms of blood supply contributing to the restoration of the "villus-crypt" system of the mucous membrane.Conclusion. Thus, in case of local ischemia in the small and large intestine, the tissue structure is restored due to adaptive mechanisms of blood supply, this preserves the viability and functionality of the intestinal wall.

Study of blood rheological parameters and NO in coronary artery disease patients with and without collaterals.

In coronary artery disease (CAD), an alternative way of improvement of blood circulation in the ischemic area of the myocardium is coronary collateral circulation. Our study aimed to investigate the rheological parameters of blood and nitric oxide (NO) content in patients with various degrees of collateral development and the likelihood of the influence of blood fluidity on collateral angiogenesis. We studied patients with stable CAD who underwent elective coronary angiography and a control group with the same mean age. We investigated patients with different degrees of developing collaterals and those without them. In studied patients, the blood plasma viscosity, aggregability, and deformability of erythrocytes, as the main indicators of blood rheology. We recorded content of stable metabolic end products of nitric oxide (NOx). Results of the studies showed that in the blood of studied patients with CAD erythrocyte aggregation was increased and NO content decreased compared to the control level; NO content was as lower, as less was the number of developed collaterals was recorded. In this work, the role of the aggregation ability of erythrocytes and the endothelial origin of NO in the direct and feedback regulatory mechanism of angiogenesis in patients with CAD are discussed.

Protection of a novel velvet antler polypeptide PNP1 against cerebral ischemia-reperfusion injury

AimWe isolated a novel polypeptide PNP1 from velvet antler and investigated the role of PNP1 in ischemia reperfusion and its associated mechanism. MethodsWe built the ischemia reperfusion mouse model by the middle cerebral artery occlusion (MCAO) approach. Thereafter, PNP-1 was injected via the tail vein, and neurological function was scored. Meanwhile, the tissue injury level was detected through hematoxylin & eosin (HE) and immunohistochemical (IHC) staining, inflammatory factor levels were determined with enzyme-linked immunosorbent assay (ELISA), while protein levels through Western blotting. In addition, vascular endothelial cells were used to construct the oxygen-glucose deprivation (OGD) injury model in vitro, so as to detect the intervention effect of PNP1 on endothelial injury. Additionally, microglial cells were utilized to construct the inflammatory injury model to examine the impact of PNP1 on the polarization of microglial cells. ResultsPNP1 suppressed hypoxic cerebral injury in MCAO mice, decreased the tissue inflammatory factors, promoted tissue angiogenesis, and reduced the ischemic penumbra area. Experimental results in vitro demonstrated that, PNP1 suppressed vascular endothelial cell injury, and inhibited microglial M1 polarization as well as inflammatory response. ConclusionVelvet antler polypeptide PNP1 isolated in this study has the anti-ischemic cerebral injury effect, and its mechanism is associated with suppressing vascular endothelial cell injury and microglial cell inflammatory response.