Ischemic Conditions Research Articles

Microglia-neuron-vascular interactions in ischemia.

Cerebral ischemia is a devastating condition that results in impaired blood flow in the brain leading to acute brain injury. As the most common form of stroke, occlusion of cerebral arteries leads to a characteristic sequence of pathophysiological changes in the brain tissue. The mechanisms involved, and comorbidities that determine outcome after an ischemic event appearto be highly heterogeneous. On their own, the processes leading to neuronal injury in the absence of sufficient blood supply to meet the metabolic demand of the cells are complex and manifest at different temporal and spatial scales. While the contribution of non-neuronal cells to stroke pathophysiology is increasingly recognized, recent data show that microglia, the main immune cells of the central nervous system parenchyma, play previously unrecognized roles in basic physiological processes beyond their inflammatory functions, which markedly change during ischemic conditions. In this review, we aim to discuss some of the known microglia-neuron-vascular interactions assumed to contribute to the acute and delayed pathologies after cerebral ischemia. Because the mechanisms of neuronal injury have been extensively discussed in several excellent previous reviews, here we focus on some recently explored pathways that may directly or indirectly shape neuronal injury through microglia-related actions. These discoveries suggest that modulating gliovascular processes in different forms of stroke and other neurological disorders might have presently unexplored therapeutic potential in combination with neuroprotective and flow restoration strategies.

Функціональна активність ядерного протеїну амфотерину та його роль у розвитку ендотоксемії

The review summarizes generalizing modern scientific data on the main functions of the protein HMGB1, and its physiological and pathological roles. Amphoterin is involved in key processes that ensure the functioning of DNA in the cell nucleus and plays an important role outside it. HMGB1 has been implicated in many human inflammatory diseases such as sepsis, ischemic reperfusion injury, neurological conditions, cardiovascular disease, autoimmune disease, and others. This manuscript describes the structure and main functions of HMGB1, discusses the significance of this alarmin as damage-associated molecular patterns, and analyzes its role in the development of inflammation and cell death. Special attention is focused on the role of HMGB1 in the development of endotoxemia, as well as data on the signaling pathways involved in its pathogenesis. Information on the results of studies of the possibility of modulating the activity of this protein using inhibitors is also considered, since understanding this may be useful for developing new therapeutic strategies aimed at treating inflammatory conditions of various origins.

Viral infection causes long term changes of the immunological milieu within the heart

Abstract Background The last two decades have brought plentiful insights and new advances in understanding virus-host interactions, and the importance of acute and latent viral infections in the modulation of the structure and function of the mammalian immune system became apparent. Despite abundant evidence demonstrating substential changes after viral infections in the immune cell composition and the local immune response within various organs such as the lungs and the gut, the same phenomena within the heart tissue has remained poorly investigated. Methods C57BL6/J 6–12-week-old female mice were infected intravenously with murine cytomegalovirus (MCMV) or left uninfected. Kinetics of viral replication within the heart were determined using a standard plaque assay. Furthermore, immune cell composition within the heart was determined by flow cytometry during acute and latent viral infection. Results Active MCMV replication within the heart peaked at day 5 post-infection (p.i.) and the replicating viral particles became undetectable by day 12 in all of the infected animals. The initial immune cell infiltration was led by the increase in the NK cell compartment, followed by a substantial increase in the T cell compartment which peaked around day 7 p.i. Furthermore, there were substantial phenotypic changes in the population of cardiac macrophages which became predominantly MHCIIhigh and Ly6Chigh. Most notable was an enlargement within the CD8 T cell population which increased around 60-fold compared to the steady state conditions. Crucially, the changes in the immune cell milieu were maintained long after cessation of active viral replication as the hearts of latently infected mice contained around 2.5 times more leukocytes (CD45+) than the hearts of non-infected animals, around 18% percent of which were CD8 T cells, compared to 5% observed in the mock-infected group. Conclusion Systemic viral infection with a ubiquitous herpesvirus causes long term alterations in the composition and phenotype of the heart immune cells which could have major consequences for myocardial coping with different pathological injuries such as a subsequent microbial infection, ischemic conditions or stress induced by hypertension or volume overload.

Electrical auricular tragus stimulation induces release of circulating cardioprotective factors in healthy human volunteers

Abstract Background Vagal activation during remote ischemic conditioning (RIC) with subsequent release of cardioprotective factors from the spleen into the circulation reduces infarct size. These humoral cardioprotective factors can be transferred with plasma-dialysate from human donors undergoing RIC to isolated recipient hearts where they reduce infarct size. Electrical auricular tragus stimulation (ATS) has been demonstrated to reduce the release of cardiac injury biomarkers and ventricular arrhythmias and to improve contractile function in patients with acute myocardial infarction. Purpose To determine whether ATS, as RIC, induces release of cardioprotective factors into the circulation. Methods Healthy volunteers (3 females, 7 males, 26±5 years) were randomized to receive ATS or RIC, respectively, with an interval of at least two weeks between protocols. ATS was induced by bipolar electrical rectangular pulses of 200 µs width and a frequency of 30 Hz. The amplitude (5.5 ± 0.81 mA) was set for each volunteer to not be perceived as uncomfortable. A microprocessor-controlled circuit periodically interrupted the stimulation signal after 5 s of stimulation for 5 s. ATS was continued over 30 min. RIC served as a reference to induce the release of cardioprotective factors by 3 x 5 min blood pressure cuff inflation at 200 mmHg on the left upper arm/ 5 min deflation. Venous blood samples were taken before and 60 min after ATS or RIC, respectively, and used to prepare plasma-dialysates (1:10 dialysis against buffer for 24 h, cut-off 12-14 kDa). Male Lewis rats were sacrificed and their hearts isolated and perfused at constant pressure with buffer. Plasma-dialysates from samples taken before and 60 min after ATS or RIC, respectively, were infused for 8 min into rat hearts followed by 2 min washout before global 30 min ischemia/ 120 min reperfusion. Infarct size was demarcated by triphenyl tetrazolium chloride staining and calculated as percent of ventricular mass. Results With infusion of plasma-dialysate before ATS, infarct size was 30.9 ± 4.5% of ventricular mass and not different from that with infusion of plasma-dialysate before RIC (35.8 ± 5.8 %). Infusion of plasma-dialysate after ATS reduced infarct size to 18.3 ± 3.9 %. This cardioprotective effect was similar to that seen with infusion of plasma-dialysate after RIC (20.1 ± 3.5 %). Conclusion ATS induces the release of cardioprotective factors into the circulation of healthy volunteers. Plasma-dialysates after ATS or RIC, respectively, reduce myocardial infarct size by the same magnitude in ex vivo isolated perfused rat hearts with global ischemia/ reperfusion.

Adjunct remote ischemic conditioning to PCI in ST-segment elevation myocardial infraction patients: Systematic review and meta-analysis

Abstract Introduction ST-segment elevation myocardial infarction (STEMI) is the most dangerous presentation of the acute coronary syndrome (ACS). Throughout the last three decades, clinicians have been attempting to reduce the short and long-term major adverse cardiac events (MACE) associated with STEMI. Remote ischemic conditioning (RIC) is one of the new adjunctive modalities to PCI in treating STEMI patients whereby brief reversible episodes of ischemia and reperfusion are applied to the tissue (by alternative cycles of inflation and deflation of a blood pressure cuff on the upper or lower limb) confers global protection and renders remote tissues resistant to ischemia/reperfusion injury. This review aims to provide reliable evidence from published randomized controlled trials (RCTs) regarding whether RIC is beneficial for STEMI patients or not. Methods We followed the PRISMA guidelines during the preparation of this systematic review and meta-analysis. A computer literature search for (PubMed, Web of Science, Scopes, and Google Scholar) was carried out. We included RCT, comparing the remote ischemic conditioning, regardless of its timing of application to PCI, with either placebo or sham procedure, in terms of both short-term and long-term cardio protection. Outcomes of myocardial salvage index, myocardial infarction size, and left ventricular ejection fraction were pooled as the standardized mean difference between the two groups from baseline to endpoint. Results 11 RCTs (7151 patients), were included in this analysis. The overall effect on short-term outcomes, was in favor of PCI only in terms of myocardial salvage index(P value=0.04, 95% CI [0.00-0.08]), and left ventricular ejection fraction(P value=0.05, 95% CI [0.02,2.16]), while the adjunctive application of remote ischemic conditioning was beneficial in terms of: myocardial infarct size ( P value=0.004, 95% CI [-3.22,-0.62]). Regarding the long-term outcomes, the overall effect did not show any benefit in either of the two groups in terms of: major adverse cardiac and cerebrovascular events (MACCE) (P value=0.13, 95% CI [0.48,1.10]), hospitalization for heart failure (P value=1.00, 95% CI [0.83,1.20]), and cardiac death (P value=0.91, 95% CI [0.73,1.32]). Conclusion The adjunctive application of RIC to PCI during treatment of STEMI patients showed a beneficial effect only on short-term reduction of myocardial infarct size, nevertheless, it was not of benefit regarding the other short and long-term metrics of myocardial salvage and left ventricular function.

Common and specific proteins and pathways in heart and cerebral ischemia

ObjectiveTo understand the similarities and differences between acute ischemic stroke and acute myocardial infarction (AMI) to help in the development of specific or common treatment strategies. MethodsUsing an aptamer-based proteomic array, we measured and compared 1310 circulating proteins in the blood of 40 patients with AIS, 9 patients with AMI, and 31 healthy controls. Pathway enrichment analysis was performed using GSEA and g:profiler. ResultsNinety-four proteins were differentially expressed in AIS, and 284 were differentially expressed in AMI. Of these, 8 were specific to cerebral ischemia, and 197 were specific to myocardial infarction. Forty-two proteins were altered in both ischemia processes. Most altered pathways in AIS could be classified as immune response, cell cycle processing, molecular transport, or signaling. Pathways altered in AMI were mostly related to lipid metabolism and transport, highlighting cholesterol metabolic processes and estrogen signaling. In both types of ischemia, we found pathways related to metabolism, specifically purine metabolism, and signaling processes, such as TNF signaling or MAPK1/3. ConclusionsThe present study revealed proteins and pathways that were specifically altered in cerebral ischemia, in cardiac ischemia, or in both diseases, providing information on the similarities and differences of ischemic conditions. The role of common and specific proteins and pathways should be explored in detail to find possible therapeutic targets.

Remote ischemic conditioning after stroke: Research progress in clinical study.

Stroke is a leading cause of global morbidity and mortality, indicating the necessity and urgency of effective prevention and treatment. Remote ischemic conditioning (RIC) is a convenient, simple, non-intrusive, and effective method that can be easily added to the treatment regime of stroke patients. Animal experiments and clinical trials have proved the neuroprotective effects of RIC on brain injury including (examples of neuroprotective effects). This neuroprotection is achieved by raising brain tolerance to ischemia, increasing local cerebral blood perfusion, promoting collateral circulations, neural regeneration, and reducing the incidence of hematomas in brain tissue. This current paper will summarize the studies within the last 2 years for the comprehensive understanding of the use of RIC in the treatment of stroke. This paper summarizes the clinical research progress of RIC on stroke (ischemic stroke and hemorrhagic stroke (HS)). This paper is a systematic review of research published on registered clinical trials using RIC in stroke from inception through November 2022. Four major databases (PUBMED, WEB OF SCIENCE, EMBASE, and ClinicalTrials.gov) were searched. Forty-eight studies were identified meeting our criteria. Of these studies, 14 were in patients with acute ischemic stroke with onset times ranging from 6 h to 14 days, seven were in patients with intravenous thrombolysis or endovascular thrombectomy, 10 were in patients with intracranial atherosclerotic stenosis, six on patients with vascular cognitive impairment, three on patients with moyamoya disease, and eight on patients with HS. Of the 48 studies, 42 were completed and six are ongoing. RIC is safe, feasible, and effective in the treatment of stroke. Large-scale research is still required to explore the optimal treatment options and mechanisms of RIC in the future to develop a breakthrough in stroke prevention and treatment.

Efficacy of remote ischemic conditioning in acute ischemic stroke patients receiving thrombolysis and thrombectomy: a meta-analysis

Efficacy of remote ischemic conditioning in acute ischemic stroke patients receiving thrombolysis and thrombectomy: a meta-analysis

Abstract 096: Hypoperfusion Intensity Ratio Suggests Collateral Status, Stroke Mechanism, and Clinical Stability in Large Vessel Occlusion

Introduction Hypoperfusion Intensity Ratio (HIR), defined by the ratio of Tmax >10s/Tmax >6s on perfusion imaging, has been directly correlated with collateral status, stroke mechanism, and clinical outcomes in patients with acute large vessel occlusions [1,2]. We report a case of a patient with mild neurological symptoms despite an acute MCA M1 occlusion in which a very favorable HIR may have predicted clinical stability, extensive atherosclerotic burden, and compensatory leptomeningeal collaterals. Our aim was to provide support of the utility of HIR in quantifying collateral status and possibly predicting the underlying stroke mechanism and stroke progression of patients with acute large vessel occlusions. Methods Case report. Results A 61‐year‐old woman with a history of hypertension and hyperlipidemia, who is an active smoker with a known right extracranial carotid stenosis presented with acute left facial droop (NIHSS 1) upon awakening. CT head did not demonstrate early ischemic changes. CT angiogram demonstrated a right MCA M1 occlusion, marked narrowing of the right common carotid artery, and severe narrowing of the proximal innominate artery (Figure 1, Image A). CT perfusion demonstrated a Tmax >6s delay of 41mL and HIR of 0, suggestive of robust collaterals (Figure 1, Image B). The patient was out of the window for tenecteplase administration. Thrombectomy was deferred due to a low NIHSS. MRI showed a right putamen and corona radiata infarct. DSA demonstrated crossed collateralization across the anterior communicating artery and robust right ACA‐MCA and PCA‐MCA leptomeningeal collaterals and retrograde filling of the brachiocephalic and right common carotid artery via the right vertebral artery. These findings were supported by quantitative MRA, which showed decreased blood flow in the right ICA, increased blood flow in right A2, increased blood flow in left A1, and retrograde right vertebral flow indicative of a brachiocephalic steal phenomenon. Her neurological exam remained stable upon discharge. She will be evaluated for brachiocephalic revascularization as an outpatient. Conclusion We present a patient with very mild symptoms due to an acute large vessel occlusion who remained clinically stable despite an acute MCA M1 occlusion, which was likely caused by ischemic conditioning related to chronic hypoperfusion secondary to severe brachiocephalic and right common carotid artery stenosis. Favorable HIR on perfusion imaging was predictive of robust collaterals, the underlying stroke mechanism, and the stable clinical course. Since clinical equipoise exists regarding the treatment of patients with low NIHSS in the setting of an acute large vessel occlusion, individualized selection remains paramount. HIR may serve as a quantitative radiographic marker to rapidly quantify collateral status and assist in decision‐making. Future studies exploring the role of HIR in predicting stroke progression are warranted.

Remote ischemic conditioning alleviates chronic cerebral hypoperfusion-induced cognitive decline and synaptic dysfunction via the miR-218a-5p/SHANK2 pathway.

Vascular cognitive impairment (VCI) due to chronic cerebral hypoperfusion (CCH), is the second leading cause of dementia. Although synaptic impairment plays a critical role in VCI, its exact mechanism remains unknown. Our previous research revealed that remote ischemic conditioning (RIC) could alleviate cognitive decline resulting from CCH, however, its effects on synaptic impairment remain unclear. In this study, we confirmed that RIC alleviated both cognitive decline and its associated synaptic dysfunction caused by CCH. RNA sequencing revealed that CCH increased in miR-218a-5p expression, which was decreased by RIC. Elevated miR-218a-5p levels limited the benefits of RIC, however, inhibiting miR-218a-5p in hippocampal CA1 neurons rescued synaptic dysfunction. Additionally, we found that SHANK2 is a downstream target of miR-218a-5p, and inhibiting SHANK2 expression reduced the alleviation caused by hypoxic conditioning in synaptic impairment in vitro. In conclusion, our results suggested that RIC alleviated synaptic impairment via the miR-218a-5p/SHANK2 pathway, which could be a potential biomarker or therapeutic target for cognitive impairment caused by CCH.

THE EFFECTS OF VARIOUS MODES OF INTERVAL HYPOXIC TRAINING IN EXPERIMENTAL MODELS OF ANXIETY AND DEPRESSION IN RATS

The development of non-drug methods for correcting stress-induced disorders and improving adaptation to stressful factors remains an urgent task of physiology, which has a great translational potential. Previously, we proposed effective methods of hypoxic hypobaric preconditioning and distant ischemic conditioning in this regard. The purpose of this work was to transfer the principles of preconditioning to the approaches of normobaric intermittent hypoxic training (IHT). The effects of five new IHT regimens (3 five-minute sessions of hypoxia of 16% O2 per day, 3 sessions of 12% O2, 7 sessions of 12% O2, 15 sessions of 12% O2, 3 sessions of 9% O2) were studied in experimental models of depression and post-traumatic stress disorder in rats. The preconditioning regime of high intensity 3x9%O2 had the most pronounced antidepressant and anxiolytic effect in models of both pathologies. With a decrease in the level of hypoxia to 12% O2, IHT regimens partially retained their effectiveness with an increase in the number of sessions. The training regime of the longest duration – 15 × 12%O2, was effective in correcting the formation of experimental depression. The intermediate regime – 7 × 12%O2, had an anxiolytic effect, while the preconditioning regime of medium intensity – 3 × 12%O2, demonstrated both an antidepressant and anxiolytic effect. The results indicate that the intensity of hypoxic exposure had the greatest impact on the effectiveness. At the same time, a decrease in the intensity to 16% O2 led to a weakening or loss of stress-protective properties. With regard to the 3 × 9%O2 regime as the most promising, it is advisable to conduct further studies to identify the molecular mechanisms that implement its stress-protective and anxiolytic effects.

Remote Ischemic Conditioning for Motor Recovery after Acute Ischemic Stroke.

Remote ischemic conditioning (RIC) has shown an impressive neuroprotective effect on acute ischemic stroke (AIS) in animal experiments. But whether chronic RIC improves long-term functional outcomes remains unclear. We performed a non-randomized controlled trial. Eligible patients (aged 18 -80 y) with hemiplegia caused by AIS were allocated to the RIC group and the control group. All participants received normal protocol rehabilitation therapy. Patients in the RIC group underwent RIC twice daily for 90 days. The outcome included the 90-day Fugl-Meyer Assessment (FMA) scores and modified Rankin's scale (mRS) scores, as well as changes in angiogenesis-related factors in serum from baseline to 90 days. Twenty-seven patients were included in the analysis (13 in the RIC group and 14 in the control group). There was no significant difference in 90-day total FMA scores between the two groups. Lower limb FMA scores at day 90 were significantly higher in the RIC group (32.8±8.7 vs. 24.8±5.4, adjusted P=0.042). The proportion of favorable outcome (mRS<2) was higher in the RIC group than that in the control group, but no significant difference was detected (8 [61.5%] vs. 7 [50%], P=0.705). A significant increase has been found in the level of epidermal growth factor (EGF) in serum (9.4 [1.1 to 25.7] vs. -8.7 [-15.1 to 4.7], P=0.036) after chronic RIC procedure. This study investigated the role that RIC plays in AIS recovery, especially in motor function. RIC may have beneficial effects on lower limbs recovery by enhancing the EGF level. The effect of RIC on motor recovery should be further validated in future studies.

Cardiomyopathy

Cardiomyopathy is a heart muscle disorder that cannot be attributed to ischemic heart disease or abnormal loading conditions such as hypertension and valvular heart disease. It can lead to the development of arrhythmia and heart failure, and is also the leading cause of sudden cardiac death in young people. Early detection is vital for delaying or preventing complications. This review discusses the four major subtypes, i.e. hypertrophic, dilated, restricted, and arrhythmogenic cardiomyopathy, which are likely to be encountered in primary care.

Pretreatment with remote ischemic conditioning attenuates testicular damage after testicular ischemia and reperfusion injury in rats.

Testicular torsion is a urological emergency. However, surgical detorsion of the torsed spermatic cord can cause testicular reperfusion injury. Although remote ischemic preconditioning (RIPC) has been convincingly shown to protect organs against ischemia/reperfusion (I/R) injury, little is known regarding the effect of RIPC on testicular torsion/detorsion-induced reperfusion injury. Therefore, we aimed to evaluate the effect of RIPC on testes after testicular I/R injury in a rat model in vivo. Male Sprague-Dawley rats were randomly classified into 4 groups: sham-operated (sham), testicular I/R (TI/R), or remote liver (RIPC liver) and limb (RIPC limb) ischemic preconditioning groups. Testis I/R was induced by 3 h of right spermatic cord torsion (720° clockwise), and reperfusion was allowed for 3 hours. In the RIPC group, four cycles of 5 min of ischemia and 5 min of reperfusion were completed 30 min prior to testicular torsion. The ERK1/2 inhibitor U0126 was administered intravenously at the beginning of reperfusion (1 mg/kg). The testes were taken for the oxidative stress evaluations, histology, apoptosis, immunohistochemical and western blotting analysis. Remote liver and limb ischemic preconditioning attenuated ipsilateral and contralateral testicular damage after testicular I/R injury. For example. RIPC reduced testicular swelling and oxidative stress, lessened structural damage, and inhibited the testicular inflammatory response and apoptosis. Furthermore, RIPC treatment enhanced testicular ERK1/2 phosphorylation postI/R. Inhibition of ERK1/2 activity using U0126 eliminated the protection offered by RIPC. Our data demonstrate for the first time that RIPC protects testes against testicular I/R injury via activation of the ERK1/2 signaling pathway.

The brain protection of MLKL inhibitor necrosulfonamide against focal ischemia/reperfusion injury associating with blocking the nucleus and nuclear envelope translocation of MLKL and RIP3K.

Mixed lineage kinase like protein (MLKL) is a key mediator of necroptosis. While previous studies highlighted the important role of MLKL as one of the central regulators of brain damage against acute ischemic neuronal injury, how the activation of MLKL mediates brain injuries and cell death remains unclear, especially in astrocytes. In a transient middle cerebral artery occlusion (tMCAO) rat model in vivo, and an oxygen-glucose deprivation and reoxygenation (OGD/Re) injury model in both primary cultured astrocytes and human astrocytes, we show that necrosulfonamide (NSA), a MLKL specific inhibitor, reduces infarction volume and improves neurological deficits in tMCAO-treated rats. In addition, NSA treatment, as well as RIP1K inhibitor Nec-1 or RIP3K inhibitor GSK-872 treatment, decreases the OGD/Re-induced leakage of LDH in both primary cultured astrocytes and human astrocytes. NSA treatment also reduces the number of propidium iodide (PI)-positive cells, and prevents the upregulation of necroptotic biomarkers such as MLKL/p-MLKL, RIP3K/p-RIP3K, and RIP1K/p-RIP1K in ischemic penumbra of cerebral cortex in tMCAO-treated rats or in OGD/Re-treated human astrocytes. Importantly, NSA treatment blocks both the nucleus and nuclear envelope localization of MLKL/p-MLKL and RIP3K/p-RIP3K in ischemic cerebral cortex induced by tMCAO. Similarly, Co-immunoprecipitation assay shows that NSA treatment decreases tMCAO- or OGD/Re- induced increased combination of MLKL and RIP3K in nuclear envelope of ischemic penumbra of cerebral cortex or of primary cultured astrocytes, respectively. RIP3K inhibitor GSK-872 also reduces tMCAO-induced increased combination of MLKL and RIP3K in nuclear envelope of ischemic penumbra of cerebral cortex. These data suggest NSA exerts protective effects against focal ischemia/reperfusion injury via inhibiting astrocytic necroptosis through preventing the upregulation of necroptotic kinases as well as blocking both the nucleus and nuclear envelope co-localization of p-MLKL and p-RIP3K. The translocation of p-MLKL, along with p-RIP3K, to the nuclear envelope and the nucleus may play a crucial role in MLKL-mediated necroptosis under ischemic conditions.

Circular RNA PTP4A2 regulates microglial polarization through STAT3 to promote neuroinflammation in ischemic stroke.

Microglial polarization plays a critical role in neuroinflammation and may be a potential therapeutic target for ischemic stroke. This study was to explore the role and underlying molecular mechanism of Circular RNA PTP4A2 (circPTP4A2) in microglial polarization after ischemic stroke. C57BL/6J mice underwent transient middle cerebral artery occlusion (tMCAO), while primary mouse microglia and BV2 microglial cells experienced oxygen glucose deprivation/reperfusion (OGD/R) to mimic ischemic conditions. CircPTP4A2 shRNA lentivirus and Colivelin were used to knock down circPTP4A2 and upregulate signal transducer and activator of transcription 3 (STAT3) phosphorylation, respectively. Microglial polarization was assessed using immunofluorescence staining and Western blot. RNA pull-down and RNA binding protein immunoprecipitation (RIP) were applied to detect the binding between circPTP4A2 and STAT3. The levels of circPTP4A2 were significantly increased in plasma and peri-infarct cortex in tMCAO mice. CircPTP4A2 knockdown reduced infarct volume, increased cortical cerebral blood flow (CBF), and attenuated neurological deficits. It also decreased pro-inflammatory factors levels in peri-infarct cortex and plasma, and increased anti-inflammatory factors concentrations 24 h post-stroke. In addition, circPTP4A2 knockdown suppressed M1 microglial polarization and promoted M2 microglial polarization in both tMCAO mice and OGD/R-induced BV2 microglial cells. Moreover, circPTP4A2 knockdown inhibited the phosphorylation of STAT3 induced by oxygen-glucose deprivation. In contrast, increased phosphorylation of STAT3 partly counteracted the effects of circPTP4A2 knockdown. RNA pull-down and RIP assays further certified the binding between circPTP4A2 and STAT3. These results revealed regulatory mechanisms of circPTP4A2 that stimulated neuroinflammation by driving STAT3-dependent microglial polarization in ischemic brain injury. CircPTP4A2 knockdown reduced cerebral ischemic injury and promoted microglial M2 polarization, which could be a novel therapeutic target for ischemic stroke.

Cardioprotective Activity of Pharmacological Agents Affecting NO Production and Bioavailability in the Early Postnatal Period after Intrauterine Hypoxia in Rats.

Intrauterine hypoxia in newborns leads to a multifaceted array of alterations that exert a detrimental impact on the cardiovascular system. The aim of this research was to assess the cardioprotective effects of modulators of the nitric oxide (NO) system, including L-arginine, Thiotriazoline, Angiolin, and Mildronate, during the early postnatal period following intrauterine hypoxia. Methods: The study involved 50 female white rats. Pregnant female rats were given a daily intraperitoneal dose of 50 mg/kg of sodium nitrite starting on the 16th day of pregnancy. A control group of pregnant rats received saline instead. The resulting offspring were divided into the following groups: Group 1-intact rats; Group 2-rat pups subjected to prenatal hypoxia (PH) and daily treated with physiological saline; and Groups 3 to 6-rat pups exposed to prenatal hypoxia and treated daily from the 1st to the 30th day after birth. Nitrotyrosine levels, eNOS, iNOS, and NO metabolites were evaluated using ELISA; to measure the expression levels of iNOS mRNA and eNOS mRNA, a PCR test was utilized. Results: Angiolin enhances the expression of eNOS mRNA and boosts eNOS activity in the myocardium of rats with ischemic conditions. Arginine and particularly Thiotriazoline exhibited a consistent impact in restoring normal parameters of the cardiac nitroxidergic system following PH. Mildronate notably raised iNOS mRNA levels and notably reduced nitrotyrosine levels, providing further support for its antioxidative characteristics.

Short-Term and Long-Term Effects of Ischemic Conditioning on Liver Transplantation: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Although liver transplantation (LT) is one of the definitive treatments for patients with end-stage liver failure, it inevitably results in ischemic reperfusion injury. It is known that prognosis is improved when temporary ischemic conditioning (IC) is applied to patients with ischemic reperfusion injury. The objective of this meta-analysis was to determine the short-term and long-term effects of IC on the clinical outcomes of LT recipients. Randomized controlled studies on IC in patients with LTs were included. Patients were compared between an IC group and a sham group. Studies were retrieved from PubMed, Embase, and Cochrane Library. The risk of bias was evaluated using RoB 2.0. Mortality, graft function, and major complications were synthesized using RevMan 5.4.1. Among 316 papers, 17 articles (1196 patients) were included. There was an insignificant increase in short-term mortality (risk ratio [RR]: 3.00, 95% CI: 0.32-28.14, P=.34). However, long-term mortality was lower in the IC group than in the sham group, but not significantly (RR: 0.75; 95% CI: 0.47-1.20, P=.23). Short-term graft function (acute graft rejection and primary graft non-function) was not improved by IC. One-year graft loss tended to show better results in the IC group (RR: 0.53, 95% CI: 0.26-1.07, P=.08). Ischemic conditioning did not have a beneficial effect on LT. Although long-term outcomes appear to be better in the IC group than in the sham group, further randomized controlled trials are needed.

Resting-state functional connectivity in a non-human primate model of cortical ischemic stroke in area F1

BackgroundThe application of functional MRI to non-human primates after stroke has not yet been undertaken. This is the first study to explore the functional connectivity changes in non-human primate models during acute stages after stroke onset. MethodsNineteen healthy male cynomolgus monkeys (4–5 years) were used in this study. The photothrombosis model was employed to induce focal ischemic stroke in F1 area in the monkey's left hemisphere. T1-weighted structural images and resting-state functional magnetic resonance imaging (rs-fMRI) of all subjects were obtained using a 3.0 Tesla MRI system on the third day following stroke. Based on the D99 atlas, the structural and functional changes of bilateral F1 areas in monkeys were analyzed using region of interest (ROI)-based functional connectivity (FC). The bilateral F1 areas were selected as the seed regions due to their crucial role in motor control and their potential to unveil the comprehensive functional reorganization of the motor system at a whole-brain level following stroke. ResultsIschemic lesions were observed after the stroke, with larger lesion volumes associated with poorer neurological dysfunction. Compared with baseline condition, left area F1 demonstrated decreased FC with the left cerebellum, left ventral pons and left 5_(PEa). When the ROI was located in the right area F1, ischemic monkeys showed decreased FC in left ventral pons, left cerebellum, left primary visual cortex and left 5_(PEa), accompanied by increased FC in the right orbitofrontal cortex. Importantly, the degree of altered FC between left area F1 and left cerebellum was associated with upper limb tone. ConclusionsThese results provide valuable insights into the early-stage functional connectivity changes in the F1 areas of monkeys under ischemic conditions, highlighting the potential involvement of specific brain regions in the pathophysiology of ischemic injury.

A comparative review of minimally invasive approaches to esophagectomy: technical considerations, variations, and outcomes

Esophageal cancer continues to rise as a public health issue, and esophagectomy remains a mainstay therapy for the disease. Surgical approaches to esophagectomy have evolved over the past few decades with the advent of laparoscopic, thoracoscopic, and robotic technologies. The aim of this review is to identify original articles and perform a comprehensive literature search to provide updates on surgical approaches and technical considerations for esophagectomy. Articles describing the surgical technique specific to robotic-assisted minimally invasive esophagectomy (RAMIE) were reviewed and included. Technical considerations reviewed were comprised of patient positioning, optimal trocar placement, dissection, indocyanine green use, kocherization, pyloric interventions, anastomotic techniques, jejunostomy tube placement, and gastric ischemic conditioning, discussing relevant outcomes for each consideration and approach. Clinical outcomes were also evaluated by comparing RAMIE to open esophagectomy and minimally invasive esophagectomy. Outcomes reviewed included lymph node harvest, intra-operative blood loss, operative times, 30-day readmission, mortality, length of stay, pulmonary complications, recurrent laryngeal nerve injury, anastomotic leak, long-term survival, and disease-free survival.