Remote ischemic preconditioning protects against cerebral ischemia injury in rats by upregulating miR-204-5p and activating the PINK1/Parkin signaling pathway

The role of hypoxia/ischemia preconditioning in ischemic stroke

Ischemic stroke can cause damage to neurons, resulting in neurological dysfunction. The main treatments in the acute phase include intravenous thrombolysis, endovascular stent-assisted vascular thrombectomy and antiplatelet therapy. Due to the limitations of the time window and the risk of early intracranial hemorrhage, finding active treatment plans is crucial for improving therapy. Preconditioning can enhance the tolerance to acute injuries such as ischemic stroke and mechanical brain injury. This tolerance, induced by stressors like ischemia and hypoxia, can become an effective and convenient treatment approach for ischemic stroke. The molecular mechanisms involved in preconditioning are extremely complex. This article focuses on the main preconditioning treatment methods for ischemic stroke, discusses the specific molecular mechanisms of different treatment methods, and explores their action pathways and effects on corresponding target cells, thus opening up a brand-new direction for the treatment strategies of ischemic stroke.

MAM-mediated mitophagy and endoplasmic reticulum stress: the hidden regulators of ischemic stroke

Ischemic stroke (IS) is the predominant subtype of stroke and a leading contributor to global mortality. The mitochondrial-associated endoplasmic reticulum membrane (MAM) is a specialized region that facilitates communication between the endoplasmic reticulum and mitochondria, and has been extensively investigated in the context of neurodegenerative diseases. Nevertheless, its precise involvement in IS remains elusive. This literature review elucidates the intricate involvement of MAM in mitophagy and endoplasmic reticulum stress during IS. PINK1, FUNDC1, Beclin1, and Mfn2 are highly concentrated in the MAM and play a crucial role in regulating mitochondrial autophagy. GRP78, IRE1, PERK, and Sig-1R participate in the unfolded protein response (UPR) within the MAM, regulating endoplasmic reticulum stress during IS. Hence, the diverse molecules on MAM operate independently and interact with each other, collectively contributing to the pathogenesis of IS as the covert orchestrator.

Remote ischemic preconditioning plays a neuroprotective role in cerebral ischemia-reperfusion mice by inhibiting mitophagy

Remote ischemic preconditioning (RIPC) represents a clinically feasible method for safeguarding vital organs against ischemic injury. However, its specific role in cerebral ischemia-reperfusion (I/R) injury remains to be definitively elucidated. In this study, we investigated the neuroprotective effects of RIPC on mice at 7 days post-cerebral I/R and its involvement in mitophagy and mitochondrial dysfunction. Cerebral I/R led to impaired brain function, as well as structural and functional damage to mitochondria. Notably, RIPC treatment ameliorated the neurological dysfunction induced by cerebral I/R. Compared with the I/R group, the expression levels of NeuN, MBP, PDH, and Tom20 were significantly elevated in the RIPC + I/R group. Furthermore, mitochondria in the RIPC + I/R group exhibited more intact structure compared to those in the I/R group. In mice subjected to I/R injury, RIPC treatment markedly increased ATP content, ADP content, TAN level and glucose uptake while upregulating expression levels of Parkin, Pink1 and P62 proteins; it also reduced both the volume of ischemic foci and the number of mitochondrial autophagosomes along with decreasing LC3B II/I ratio. In conclusion, RIPC may exert a neuroprotective role by inhibiting excessive mitophagy during subacute stages following an ischemic stroke.

Unlocking the secrets of aging: Epigenetic reader BRD4 as the target to combatting aging-related diseases

BACKGROUND

Aging, a complex and profound journey, leads us through a labyrinth of physiological and pathological transformations, rendering us increasingly susceptible to aging-related diseases. Emerging investigations have unveiled the function of bromodomain containing protein 4 (BRD4) in manipulating the aging process and driving the emergence and progression of aging-related diseases.

AIM OF REVIEW

This review aims to offer a comprehensive outline of BRD4's functions involved in the aging process, and potential mechanisms through which BRD4 governs the initiation and progression of various aging-related diseases.

KEY SCIENTIFIC CONCEPTS OF REVIEW

BRD4 has a fundamental role in regulating the cell cycle, apoptosis, cellular senescence, the senescence-associated secretory phenotype (SASP), senolysis, autophagy, and mitochondrial function, which are involved in the aging process. Several studies have indicated that BRD4 governs the initiation and progression of various aging-related diseases, including Alzheimer's disease, ischemic cerebrovascular diseases, hypertension, atherosclerosis, heart failure, aging-related pulmonary fibrosis, and intervertebral disc degeneration (IVDD). Thus, the evidence from this review supports that BRD4 could be a promising target for managing various aging-related diseases, while further investigation is warranted to gain a thorough understanding of BRD4's role in these diseases.

MicroRNA-based interventions in aberrant cell cycle diseases: Therapeutic strategies for cancers, central nervous system disorders and comorbidities

Malignant tumors and central nervous system (CNS) disorders are intricately linked to a process known as "aberrant cell cycle re-entry," which plays a critical role in the progression of these diseases. Addressing the dysregulation in cell cycles offers a promising therapeutic approach for cancers and CNS disorders. MicroRNAs (miRNAs) play a crucial role as regulators of gene expression in cell cycle transitions, presenting a promising therapeutic avenue for treating these disorders and their comorbidities. This review consolidates the progress made in the last three years regarding miRNA-based treatments for diseases associated with aberrant cell cycle re-entry. It encompasses exploring fundamental mechanisms and signaling pathways influenced by miRNAs in cancers and CNS disorders, particularly focusing on the therapeutic effects of exosome-derived miRNAs. The review also identifies specific miRNAs implicated in comorbidity of cancers and CNS disorders, discusses the future potential of miRNA reagents in managing cell cycle-related diseases.

Effect of remote ischemic preconditioning intervention on serum levels of microRNA-582-5p/HMGB1 in patients with acute cerebral infarction

OBJECTIVE

Acute cerebral infarction (ACI) contributes to disability and death accross the globe. Remote ischemic preconditioning (RIPC) reduces cerebral infarct size and improves neurological function in ACI. We conducted this research to reveal the effects of RIPC intervention on serum levels of microRNA-582-5p (miR-582-5p)/high mobility group box-1 protein (HMGB1), inflammation, oxidative stress and neurological function in patients with ACI.

METHODS

In this study, 158 patients with ACI were prospectively selected and randomized into the control (administered symptomatic medication alone) and the RIPC (underwent RIPC of the limbs based on medication) groups, with their clinical baseline data documented. Serum levels of miR-582-5p, and HMGB1 and inflammatory factors [tumor necrosis factor alpha (TNF-α)/interleukin-1beta (IL-1β)/IL-10] were assessed by RT-qPCR/ELISA, followed by comparisons of oxidative stress indices [glutathione-peroxidase (GSH-Px)/catalase (CAT)/superoxide dismutase (SOD)] using a fully automatic biochemical analyzer. Correlations between serum miR-582-5p with serum HMGB1, and between their levels with TNF-α/IL-1β/IL-10 were analyzed by Pearson analysis. The NIHSS score/Barthel Index scale were used to assess neurological function/daily living ability. Intervention safety for ACI patients was evaluated.

RESULTS

RIPC intervention increased serum miR-582-5p levels and decreased serum HMGB1 levels in ACI patients. RIPC intervention significantly reduced inflammation (diminished TNF-α/IL-1β levels, increased IL-10 level) and oxidative stress (elevated GSH-Px/CAT/SOD levels) in ACI patients. Serum miR-582-5p was negatively correlated with TNF-α and IL-1β levels, while positively correlated with IL-10 level, while HMGB1 was positively correlated with TNF-α and IL-1β levels, while negatively correlated with IL-10 level. miR-582-5p was negatively correlated with HMGB1. RIPC intervention improved neurological function (reduced NIHSS, increased Barthel scores) in ACI patients to some extent. RIPC had certain effectiveness and safety in the treatment of ACI.

CONCLUSION

After RIPC intervention, serum miR-582-5p levels were increased, HMGB1 levels were decreased, and inflammation and oxidative stress were reduced in ACI patients, which mitigated neurological deficits, improved patients' ability to perform life activities, and exerted neuroprotective effects to some extent.

NGAL in the Development of Acute Kidney Injury in a Murine Model of Remote Ischaemic Preconditioning and Liver Ischaemia Reperfusion

Acute kidney injury (AKI) is common following liver transplantation and is associated with liver ischeamia reperfusion (IR) injury. The purpose of this study was to use a mouse model of liver IR injury and AKI to study the role of Neutrophil Gelatinase Associated Lipocalin (NGAL), a biomarker of AKI, in liver IR injury and AKI. We demonstrate an adapted, reproducible model of liver IR injury and AKI in which remote ischemic preconditioning (RIPC) by repeated episodes of hindleg ischemia prior to liver IR reduced the severity of the IR injury. In this model, serum NGAL at 2 h post reperfusion correlated with AKI development early following IR injury. This early rise in serum NGAL was associated with hepatic but not renal upregulation of NGAL mRNA, suggesting NGAL production in the liver but not the kidney in the early phase post liver IR injury.

Mitochondrial Kinase Signaling for Cardioprotection

Myocardial ischemia/reperfusion injury is reduced by cardioprotective adaptations such as local or remote ischemic conditioning. The cardioprotective stimuli activate signaling cascades, which converge on mitochondria and maintain the function of the organelles, which is critical for cell survival. The signaling cascades include not only extracellular molecules that activate sarcolemmal receptor-dependent or -independent protein kinases that signal at the plasma membrane or in the cytosol, but also involve kinases, which are located to or within mitochondria, phosphorylate mitochondrial target proteins, and thereby modify, e.g., respiration, the generation of reactive oxygen species, calcium handling, mitochondrial dynamics, mitophagy, or apoptosis. In the present review, we give a personal and opinionated overview of selected protein kinases, localized to/within myocardial mitochondria, and summarize the available data on their role in myocardial ischemia/reperfusion injury and protection from it. We highlight the regulation of mitochondrial function by these mitochondrial protein kinases.

Temporal expression profiles of microRNAs associated with acute phase of brain ischemia in gerbil hippocampus

Neuroprotective therapeutic potential for restoring dysregulated microRNA (miRNA) expression has previously been demonstrated in a gerbil cerebral infarction model. However, since temporal changes in miRNA expression profiles following stroke onset are unknown, miRNAs proving to be useful therapeutic targets have yet to be identified. We evaluated cognitive function, hippocampal neuronal cell death, and microarray-based miRNA expression profiles at 5, 9, 18, 36, and 72 h after 5-min whole brain ischemia in gerbils. A decline in cognitive function occurred in parallel with increased neuronal cell death 36-72 h after ischemia. The Jonckheere-Terpstra test was used to analyze miRNA expression trends 5-72 h after ischemia. The expression levels of 63 miRNAs were significantly upregulated, whereas 32 miRNAs were significantly downregulated, monotonically. Of the 32 monotonically downregulated miRNAs, 18 showed the largest decrease in expression 5-9 h after ischemia. A subset of these dysregulated miRNAs (miR-378a-5p, miR-204-5p, miR-34c-5p, miR-211-5p, miR-34b-3p, and miR-199b-3p) could be associated with brain ischemia and neuropsychiatric disorders.

Research hotspots and frontiers of preconditioning in cerebral ischemia: A bibliometric analysis

Background

Preconditioning is a promising strategy against ischemic brain injury, and numerous studies in vitro and in vivo have demonstrated its neuroprotective effects. However, at present there is no bibliometric analysis of preconditioning in cerebral ischemia. Therefore, a comprehensive overview of the current status, hot spots, and emerging trends in this research field is necessary.

Materials and methods

Studies on preconditioning in cerebral ischemia from January 1999-December 2022 were retrieved from the Web of Science Core Collection (WOSCC) database. CiteSpace was used for data mining and visual analysis.

Results

A total of 1738 papers on preconditioning in cerebral ischemia were included in the study. The annual publications showed an upwards and then downwards trend but currently remain high in terms of annual publications. The US was the leading country, followed by China, the most active country in recent years. Capital Medical University published the largest number of articles. Perez-Pinzon, Miguel A contributed the most publications, while KITAGAWA K was the most cited author. The focus of the study covered three areas: (1) relevant diseases and experimental models, (2) types of preconditioning and stimuli, and (3) mechanisms of ischemic tolerance. Remote ischemic preconditioning, preconditioning of mesenchymal stem cells (MSCs), and inflammation are the frontiers of research in this field.

Conclusion

Our study provides a visual and scientific overview of research on preconditioning in cerebral ischemia, providing valuable information and new directions for researchers.

Effect of remote ischemic preconditioning on postoperative cognitive dysfunction in adult patients with general anesthesia: a meta-analysis

BACKGROUND

Remote ischemic preconditioning (RIPC) is proven to have neuroprotective protective effects. Nevertheless, the impact of RIPC on postoperative cognitive dysfunction (POCD) in patients undergoing general anesthesia is controversial. This meta-analysis of randomized controlled trials (RCTs) aimed to assess the effect of RIPC on POCD in adults after general anesthesia.

METHODS

Relevant literature was obtained by searching Embase, PubMed, Web of Science, Cochrane Library, Wanfang, and China National Knowledge Infrastructure (CNKI) databases in July 2022. RCTs were included to assess the influences of RIPC on POCD in adults following general anesthesia. Two investigators independently performed literature screening, data extraction, and quality assessment based on the inclusion and exclusion criteria. The incidence of POCD, operation time, and hospital stay were analyzed by Review manager5.4 software.

RESULTS

Thirteen RCTs with 1122 participants were selected for this meta-analysis. Compared to the control group, RIPC decreased the incidence of POCD (OR = 0.50, 95% CI 0.31-0.82), as well as reduced the duration of hospitalization (MD = - 0.98, 95% CI - 1.69 to - 0.27), but did not prolong operative time (MD = - 2.65, 95% CI - 7.68 to 2.37).

CONCLUSION

RIPC reduced the incidence of POCD in adult patients after general anesthesia and accelerated their discharge.

Ischemic preconditioning attenuates endoplasmic reticulum stress-dependent apoptosis of hepatocytes by regulating autophagy in hepatic ischemia-reperfusion injury

Hepatic ischemia-reperfusion injury (HIRI) usually occurs during subtotal hepatectomy and severely damages liver function during the perioperative period. Endoplasmic reticulum stress (ERS) dependent apoptosis has been suggested to play a crucial role in HIRI progression. The present study focused on the regulatory effect of autophagy activation induced by ischemic preconditioning (IPC) on ERS-dependent apoptosis of hepatocytes in HIRI. A HIRI mouse model and oxygen-glucose deprivation/reperfusion (OGD/R) AML-12 hepatocyte cell lines were constructed to evaluate the protective effect of IPC in vivo and in vitro. The protein levels of p-eIF2α, CHOP, and cleaved caspase-12 were used to evaluate the ERS-dependent apoptosis, whereas LC3-II and p62 were considered as the autophagy activation markers. The beneficial molecular chaperones GRP78, HSP60, and HSP70 were also tested to evaluate autophagy. HIRI significantly increased ERS-dependent apoptosis markers and the number of apoptotic cells and damaged liver function. The ERS inhibitor salubrinal significantly alleviated liver injury in HIRI and OGD/R hepatocytes. Furthermore, both remote IPC and direct IPC significantly alleviated liver injury and inflammatory cell infiltration. IPC also upregulated LC3-II, downregulated p62 expression, and increased the mRNA levels of GRP78, HSP60, and HSP70 in HIRI mice and OGD/R hepatocytes, indicating the activation of autophagy by IPC. The autophagy inhibitor 3-methyladenine significantly attenuated the protective effects of IPC on ERS-dependent apoptosis and liver function, whereas the autophagy activator rapamycin mimicked the protective effects of IPC on ERS-dependent apoptosis in vivo and in vitro, suggesting a regulatory role of autophagy in ERS-dependent apoptosis. These results demonstrated that IPC could induce moderate autophagy and upregulate a few molecular chaperones to strengthen endogenous defense mechanisms, which is beneficial for alleviating ERS-dependent apoptosis and protecting hepatocytes from HIRI.

The autophagy in ischemic stroke: A regulatory role of non-coding-RNAs

Ischemic stroke (IS) is a central nervous system neurological disorder ascribed to an acute focal trauma, with high mortality and disability, leading to a heavy burden on family and society. Autophagy is a self-digesting process by which damaged organelles and useless proteins are recycled to maintain cellular homeostasis, and plays a pivotal role in the process of IS. Non-coding RNAs (ncRNAs), mainly contains microRNA, long non-coding RNA and circular RNA, have been extensively investigated on regulation of autophagy in human diseases. Recent studies have implied that ncRNAs-regulating autophagy participates in pathophysiological process of IS, including cell apoptosis, inflammation, oxidative stress, blood-brain barrier damage and glial activation, which indicates that regulating autophagy by ncRNAs may be beneficial for IS treatment. This review summarizes the role of autophagy in IS, as well as focuses on the role of ncRNAs-mediated autophagy in IS, for the development of potential therapeutic strategies in this disease.

Effects of Remote Ischemic Preconditioning on Postoperative Cognitive Dysfunction in Elderly Patients with Laparoscopic Cholecystectomy

Purpose

We hypothesized that remote ischemic preconditioning (RIPC) could improve postoperative cognitive dysfunction (POCD) in elderly patients following laparoscopic cholecystectomy (LC).

Patients and Methods

Eighty-eight patients were randomly assigned to either the control or the RIPC group. The RIPC was applied on the right upper limb using a blood pressure cuff inflating 200 mmHg, consisting of 3 cycles of 5 min ischemia and 5 min reperfusion. Serum concentrations of Neuron-specific Enolase (NSE) and Brain-Derived Neurotrophic Factor (BDNF) were collected at one-day preoperative (T0), at the end of the operation (T4) and one-day postoperative (T5). Z score was tested at T0 and 3 days after the operation (T6). POCD was determined if there were two Z scores ≥1.96 at the same time or an average Z score ≥1.96.

Results

There was no significant difference in the Z score of each test between the two groups at T0 (P > 0.05). Notably, the duration of Stroop test C was significantly shorter in the RIPC group than that in the Control group at T6 (P = 0.01). POCD occurred in 1/44 (2.3%) patients in the RIPC group and 8/44 (18.2%) patients in the control group at T6 (P=0.035). In addition, serum NSE concentration was significantly decreased, but serum BDNF concentration was increased compared with the control group at T4 and T5 (P<0.001).

Conclusion

RIPC could reduce the incidence of POCD in elderly patients after laparoscopic cholecystectomy.