Cell biology of ischemia/reperfusion injury

Investigation into recent advanced strategies of reactive oxygen species-mediated therapy based on Prussian blue: Conceptualization and prospect

Prussian blue (PB) has garnered considerable scholarly interest in the field of biomedical research owing to its notably high biocompatibility, formidable multi-enzyme mimetic capabilities, and established clinical safety profile. These properties in combination with its reactive oxygen species (ROS) scavenging activity have facilitated significant progress in disease diagnosis and therapy for various ROS-mediated pathologies, where overproduced ROS exacerbates disease symptoms. Additionally, the underlying ROS-associated mechanisms are disease-specific. Hence, we systematically examined the role of ROS and its basic underlying mechanisms in representative disease categories and comprehensively reviewed the effect of PB-based materials in effectively alleviating pathological states. Furthermore, we present a thorough synthesis of disease-specific design methodologies and prospective directions for PB as a potent ROS-scavenging biotherapeutic material with emphasis on its applications in neurological, cardiovascular, inflammatory, and other pathological states. Through this review, we aim to accelerate the progress of research on disease treatment using PB-based integrated therapeutic system.

Rapid synergistic thrombolysis of ischemic stroke guided by high-resolution and high-speed photoacoustic cerebrovascular imaging

Thrombosis is the major cause of ischemic stroke and poses a serious health burden globally. Current thrombolytic strategies, such as systematic administration of recombinant human tissue plasminogen activator (rt-PA), are challenged by limited thrombolysis efficiency due to low targeting ability and a short plasma half-life. Here, we report a rapid synergistic strategy that integrates sonothrombolysis and rt-PA mediated pharmacological thrombolysis to achieve accurate and efficient treatment of ischemic stroke. The strategy (PLPA@PFP) uses a platelet-biomimetic membrane as a carrier to deliver both perfluoropentane (PFP) and rt-PA, prolonging half-life and effectively accumulating at the thrombus within 0.5 hours. Upon exposure to focused ultrasound, PFP-based cavitation effects significantly enhance thrombus breakdown and rt-PA penetration, enabling synergistic sono/pharmacological thrombolysis both in vitro and in vivo. High-resolution photoacoustic (PA) imaging provides direct assessment of vascular reperfusion following therapeutic intervention in a murine model of ischemic stroke, offering important guidance for clinical treatment.

Selenium-loaded porous silica nanospheres improve cardiac repair after myocardial infarction by enhancing antioxidant activity and mitophagy

Myocardial infarction (MI) is the leading cause of death globally, often resulting to significant loss of cardiac function. A key factor in the pathological progression of MI is the excessive generation of reactive oxygen species (ROS) by dysfunctional mitochondria. However, no antioxidant therapy has been approved for clinical treatment of MI to date. In this study, selenium-loaded porous silica nanospheres (Se@PSN) are synthesized as a novel therapeutic approach for MI. These nanospheres are capable of neutralizing various ROS, thereby reducing hypoxia-induced myocardial cell damage. Additionally, Se@PSN promote the upregulation of antioxidant proteins, providing sustained intracellular ROS scavenging, which helps reduce infarct size and preserve cardiac function post-MI. The sustained antioxidant effects of Se@PSN are attributed to their ability to safeguard mitochondrial function by modulating oxidative phosphorylation, mitochondrial dynamics, and mitophagy. The activation of mitophagy by Se@PSN is achieved through the upregulation of HIF-1α expression. In conclusion, Se@PSN show significant potential for clinical translation as a novel therapeutic strategy for MI.

HBCOC attenuates cerebral ischemia-reperfusion injury in mice by inhibiting the inflammatory response and autophagy via TREM-1/ERK/NF-κB

OBJECTIVE

Hemoglobin-based carbon monoxide carrier (HBCOC) can dissociate carbon monoxide and ameliorate organ damage by inhibiting inflammation and oxidative stress. In this study, we evaluated its effect on cerebral ischemia-reperfusion injury in mice and explored its potential mechanism.

METHODS

A middle cerebral artery occlusion/reperfusion (MCAO/R) mouse model was established using the wire embolization method, and HBCOC or equivalent normal saline was administered via the tail vein during reperfusion. HE staining and TEM were used to observe the injury in the tissue. The levels of IL-1β, IL-6, TNF-α were detected by ELISA and RT-qPCR, meantime, western blotting were used to detect expressions of TREM-1, ERK, NF-κB,LC3 and P62.

RESULTS

We found that the HBCOC treatment alleviated nerve injury and reduced the cerebral infarction area caused by ischemia-reperfusion, simultaneously lowered the expression of IL-1β, IL-6, and TNF-α in plasma and brain tissues. HBCOC suppressed the levels of LC3II, lysosomes, and autophagy in the brain, suggesting potent inhibition of autophagy. Mechanistic analysis indicated that the expression of TREM-1/ERK/NF-κB pathway-related proteins and mRNA was higher in the saline group than that in the HBCOC group. HBCOC combined with the targeting TREM-1 receptor inhibitors LP17 inhibited the expression of the TREM-1 protein, further reducing the release of inflammatory factors and autophagy, restoring nerve function and infarct area after reperfusion, and exerting an overall protective effect against cerebral reperfusion injury. In summary, our results indicated that HBCOC alleviated cerebral ischemia-reperfusion injury in mice and inhibited inflammation and autophagy via TREM-1.

Neuroprotective effects of hirudin against cerebral ischemia-reperfusion injury via inhibition of CCL2-mediated ferroptosis and inflammatory pathways

Cerebral ischemia-reperfusion injury (CIRI) is a leading cause of neurological impairment in stroke, primarily correlated to oxidative stress, inflammation, and ferroptosis. This study investigates the neuroprotective effects of hirudin on CIRI, focusing on its role in modulating neuronal survival, oxidative stress, and ferroptosis markers through inhibition of CCL2. A middle cerebral artery occlusion (MCAO) model in mice and an oxygen-glucose deprivation/reoxygenation (OGD/R) model in HT22 cells were used to simulate ischemic conditions. Hirudin significantly improved neurological function and reduced cerebral edema and infarct size in the MCAO model. In vitro, hirudin enhanced neuronal viability and reduced apoptosis in OGD/R-stimulated cells. Integrative network pharmacology and transcriptomic analysis identified CCL2 as a potential target of hirudin. Hirudin treatment suppressed CCL2 expression, which in turn reduced the TLR4/NF-κB signaling activation, thereby mitigating ferroptosis and inflammatory responses in ischemic neurons. Overexpression of CCL2 partially reversed these protective effects, underscoring its role in ischemic injury. These findings suggest that hirudin alleviates CIRI by modulating CCL2 and preventing ferroptosis, offering insights into its potential as a therapeutic agent for ischemic conditions.

Sequential administration of febuxostat and vitamin E protects against testicular ischemia/reperfusion injury via inhibition of sperm DNA damage in Wistar rats

The pathway of testicular ischemia-reperfusion injury (TIRI) has been shown to involve reactive oxygen species (ROS) generation in the ischemic phase and later phase of reperfusion. This study was therefore designed to investigate the effect of blockage of ROS in the ischemic and reperfusion phases of TIRI. Thirty male Wistar rats were grouped into five groups (n = 6 rats each): sham, torsion + detorsion (TD), febuxostat (FEB)-administered (TFD) group, vitamin E (V)-administered (TDV) group, and FEB and vitamin E-administered (TFDV) group. Blood samples (for inflammatory and hormonal assay), testicular (for oxidative stress and histopathology), and epididymal (for sperm DNA damage and indices) tissues were collected after 3 days of detorsion. The TFD and TFDV groups showed a significant reduction in XO and MDA (p < 0.001; η2 > 0.7), as well as a concomitant increase in CAT, thiols, and SOD levels when compared with the TD group (p < 0.01, η2 > 0.5). The TFD group significantly reduced all inflammatory markers (p < 0.05; η2 = 0.75). The observed increase (p < 0.05; η2 = 0.92) in LH level, in response to a low level of testosterone in the TD group, was significantly raised in TFD and TFDV groups. The observed decrease (p < 0.001) in inhibin level in the TD group was raised (p < 0.05; η2 = 0.90) in the TDV group only. A significant increase (p < 0.001) in sperm DNA damage in the TD group was significantly reduced (p < 0.05; η2 = 0.88) in all the treatment groups while the reduced sperm viability (p < 0.01) in the TD group was increased (p < 0.05) in the TFDV group only. There was an improvement in the testicular cytoarchitecture in the TFD and TFDV groups. This study showed that sequential administration of febuxostat in the ischemic phase of TT and vitamin E in the later phase of reperfusion protects the testes against TIRI via inhibition of oxidative stress, inflammation, and sperm DNA damage.

3,4-Dimethoxychalcone alleviates limb ischemia/reperfusion injury by TFEB-mediated autophagy enhancement and antioxidative response

Caloric restriction mimetics (CRMs) replicate the positive effects of caloric restriction (CR) and have demonstrated therapeutic benefits in neuroinflammatory and cardiovascular diseases. However, it remains uncertain whether CRMs enhance functional recovery following ischemia/reperfusion (I/R) injury, as well as the specific mechanisms involved in this process. This study examines the therapeutic potential of the CRM 3,4-dimethoxychalcone (3,4-DC) in limb I/R injury. Histology, tissue swelling analysis, and laser doppler imaging (LDI) were used to assess the viability of the limbs. Western blotting and immunofluorescence were utilized to examine apoptosis levels, oxidative stress (OS), autophagy, transcription factor EB (TFEB) activity, and mucolipin 1 (MCOLN1)-calcineurin signaling pathway. The administration of 3,4-DC notably alleviated hypoperfusion, tissue swelling, skeletal muscle fiber damage, and cellular injury in the limb caused by I/R. The pharmacological blockade of autophagy negated the antioxidant and antiapoptotic effects of 3,4-DC. Moreover, RNA interference-mediated TFEB silencing eliminated the 3,4-DC-induced restoration of autophagy, antioxidant response, and antiapoptotic effects. Additionally, our findings revealed that 3,4-DC modulates TFEB activity via the MCOLN1-calcineurin signaling pathway. 3,4-DC facilitates functional recovery by enhancing TFEB-driven autophagy, while simultaneously suppressing oxidative stress and apoptosis following I/R injury, suggesting its potential value in clinical applications.

Fluid Shear Stress-Regulated Vascular Remodeling: Past, Present, and Future

The vascular system remodels throughout life to ensure adequate perfusion of tissues as they grow, regress, or change metabolic activity. Angiogenesis, the sprouting of new blood vessels to expand the capillary network, versus regression, in which endothelial cells die or migrate away to remove unneeded capillaries, controls capillary density. In addition, upstream arteries adjust their diameters to optimize blood flow to downstream vascular beds, which is controlled primarily by vascular endothelial cells sensing fluid shear stress (FSS) from blood flow. Changes in capillary density and small artery tone lead to changes in the resistance of the vascular bed, which leads to decreased or increased flow through the arteries that feed these small vessels. The resultant changes in FSS through these vessels then stimulate their inward or outward remodeling, respectively. This review summarizes our knowledge of endothelial FSS-dependent vascular remodeling, offering insights into potential therapeutic interventions. We first provide a historical overview, then discuss the concept of set point and mechanisms of low-FSS-mediated and high-FSS-mediated inward and outward remodeling. We then cover in vivo animal models, molecular mechanisms, and clinical implications. Understanding the mechanisms underlying physiological endothelial FSS-mediated vascular remodeling and their failure due to mutations or chronic inflammatory and metabolic stresses may lead to new therapeutic strategies to prevent or treat vascular diseases.

Assessment of Amniotic Fluid as a Preservation Solution in Pig Livers Undergoing Machine Perfusion

INTRODUCTION

Ischemia-reperfusion injury in organ transplantation highlights the need for advanced preservation techniques. This study evaluates the effectiveness of amniotic fluid (AF) compared to static cold storage and histidine-tryptophan-ketoglutarate (HTK) solution in preserving pig livers subjected to hypothermic oxygenated machine perfusion (HOMP) and ex vivo normothermic reperfusion.

MATERIALS AND METHODS

Fifteen pig livers underwent warm ischemia for 1 h, followed by preservation under three conditions: cold storage (group 1, n = 3), HOMP with HTK (group 2, n = 3), and HOMP with AF (group 3, n = 3). Perfusion lasted 4 h, followed by 2 h of ex vivo reperfusion. Assessments included hepatic bile production, sphingomyelin levels, reactive oxygen/nitrogen species, antioxidant capacity, tissue oxygen saturation, flow dynamics, blood gas analyses, biochemical markers, and histopathological and immunohistochemical evaluations.

RESULTS

AF-HOMP showed superior blood flow, lower vascular resistance, higher oxygen saturation, and better organ protection than HTK. Blood gas measurements demonstrated stable physiological levels after reperfusion. AF-HOMP improved bile production, sphingomyelin levels, glycogen preservation, and reduced parenchymal necrosis, hepatocyte vacuolization, and sinusoidal obstruction. Immunohistochemical analysis indicated protective effects on bile duct function, apoptosis, endothelial activation, and cell proliferation.

CONCLUSIONS

AF-HOMP outperformed HTK in preserving liver tissue during warm ischemia, HOMP, and reperfusion. AF is a promising, cost-effective, and accessible alternative for liver preservation, potentially expanding donor pools and improving transplantation outcomes. Further research is warranted to explore its broader applications.

The Impact of Opioids on Epigenetic Modulation in Myocardial Ischemia and Reperfusion Injury: Focus on Non-coding RNAs

Myocardial ischemia-reperfusion injury (IRI) is a major issue in cardiovascular medicine, marked by tissue damage from the restoration of blood flow after ischemia. Opioids, known for their pain-relieving properties, have emerged as potential cardioprotective agents in IRI. Recent research suggests opioids influence epigenetic mechanisms-such as histone modifications and non-coding RNAs (ncRNAs)-which are essential for regulating gene expression and cellular responses during myocardial IRI. This review delves into how opioids like remifentanil affect histone modifications, DNA methylation, and ncRNAs, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). Remifentanil postconditioning (RPC) reduces apoptosis in cardiomyocytes through histone deacetylation, specifically downregulating histone deacetylase 3 (HDAC3). Similarly, opioids impact miRNAs such as miR- 206 - 3p and miR- 320 - 3p, and lncRNAs like TINCR and UCA1, which influence apoptosis, inflammation, and oxidative stress. Understanding these interactions highlights the potential for opioid-based therapies in mitigating IRI-induced myocardial damage.

A glibenclamide analog lacking the cyclohexylurea portion fails to block ischemic preconditioning-induced mitochondrial and cardiac protection against ischemia/reperfusion injury

Despite significant research, there are no definitive therapies to prevent ischemia/reperfusion injury. During reperfusion, mitochondrial reactive oxygen species (ROS) cause cell damage. Ischemic preconditioning (IP), characterized by brief cycles of ischemia and reperfusion, activates mitochondrial ATP-sensitive potassium channels (mitoKATP) and provides cardioprotection. The aim of the present study is to investigate the impact of a truncated glibenclamide (lacking the cyclohexylurea portion - IMP-A) in ischemic preconditioning (IP)-mediated cardioprotection. Our study shows that IMP-A (2-5 μM) does not inhibit the protective effects of IP against ischemia/reperfusion damage in isolated rat hearts. In this context, IP hearts (with or without IMP-A) exhibited preserved cardiac function, as indicated by stable left ventricular developed pressure, maximal and minimal first derivatives, and rate-pressure product, along with a reduced infarct size following ischemia/reperfusion injury. Conversely, glibenclamide (2 μM - a well-characterized mitoKATP inhibitor) abolished the protective effects of IP against ischemia/reperfusion damage. Mitochondria isolated from reperfused IP hearts (treated or not with IMP-A) produced significantly lower levels of mitochondrial ROS and had lower susceptibility to Ca2+-induced swelling secondary to mitochondrial permeability transition pore (mPTP) opening. Additionally, IP hearts (treated or not with IMP-A) had preserved protein sulfhydryls. Glibenclamide elevated mitochondrial ROS production and negatively impacted mPTP and the sulfhydryl protection seen in IP hearts. Importantly, mitochondrial O2 consumption was preserved in IP hearts (treated or not with IMP-A), and this preservation was disrupted by glibenclamide but not by IMP-A. These findings suggest that the cyclohexylurea group of glibenclamide is essential for its ability to block IP-mediated cardioprotection, providing valuable insights for developing novel therapeutic strategies.

Therapeutic effects of lomerizine on vasculopathy in Fabry disease

Fabry disease (FD) is a lysosomal storage disorder in which α-galactosidase (GLA) deficiency leads to a build-up of globo-triaosylceramide (Gb3) in various cell types. Gb3 accumulation leads to the abnormalities of microvascular function associated with FD. Previously, we discovered significant abnormalities in vascular endothelial cells (VECs) derived from FD-induced pluripotent stem cells. We then used a cell-based system to screen a group of clinical compounds for candidates capable of rescuing those abnormalities. Lomerizine was one of the most promising candidates because it alleviated a variety of FD-associated phenotypes both in vitro and in vivo. Lomerizine reduced mitochondria Ca2+ levels, ROS generation, and the maximal respiration of FD-VECs in vitro. This led to a suppression of the endothelial-to-mesenchymal transition (EndMT) and rescued FD-VEC function. Furthermore, FD-model mice (Gla-/-/TSP1Tg) treated orally with lomerizine for 6 months showed clear improvement of several FD phenotypes, including left ventricular hypertrophy, renal fibrosis, anhidrosis, and heat intolerance. Thus, our results suggest lomerizine as a novel candidate for FD therapy.

Bionic nanovesicles sequentially treat flaps with different durations of ischemia by thrombolysis and prevention of ischemia-reperfusion injury

Flap transplantation is a critical part of the recovery process for patients who have undergone tumor resection. However, the process of ischemia-reperfusion injury during flap transplantation and the resulting high-risk thrombotic microenvironment are unavoidable. In this study, based on an in-depth investigation of the ischemia time and prognosis of transplanted flaps, we propose a treatment strategy using sequential thrombolysis and ischemia-reperfusion injury prevention tailored to the ischemia time. This approach is designed to minimize the likelihood of thrombus formation and to clear the intravascular inflammatory microenvironment, with the aim of preventing and salvaging ischemic flaps. Specifically, we have successfully constructed a clinical-grade bionic vesicle, UK-PBNZ@PM, a system that cleverly incorporates drug components that have been widely used in clinical applications, thereby demonstrating a high degree of clinical translational potential. Prussian blue nano-enzymes (PBNZ) are the core component and demonstrate remarkable efficacy against ischemia-reperfusion injury due to their excellent biocompatibility, robust reactive oxygen species (ROS) scavenging capacity and anti-inflammatory properties. At the same time, urokinase (UK), a key pharmaceutical agent in antithrombotic therapy, has been effectively incorporated into the system, enhancing its ability to prevent and treat thrombosis. In addition, the integration of a platelet membrane (PM) has endowed the bionic vesicles with precise targeting and delivery capabilities, ensuring that the drugs can reach the lesion directly and facilitate efficient and precise release. The experimental results demonstrated that an ischemia-timed strategy can not only efficiently promote thrombolysis, but also effectively remove harmful elements in the microenvironment of ischemia-reperfusion injury. This discovery represents a new and promising approach to the treatment of thrombosis.

Mechanisms and preventive measures of ALDH2 in ischemia‑reperfusion injury: Ferroptosis as a novel target (Review)

Ischemia‑reperfusion injury (IRI) refers to tissue or organ damage that occurs following a period of inadequate blood supply (ischemia) followed by restoration of blood flow (reperfusion) within a short time frame. This phenomenon is prevalent in clinical conditions such as cardiovascular and cerebrovascular disease, organ transplantation and stroke. Despite its frequency, effective therapeutic strategies to mitigate IRI remain elusive in clinical practice, underscoring the need for a deeper understanding of its molecular mechanisms. Aldehyde dehydrogenase 2 (ALDH2), a key enzyme in alcohol metabolism, serves a role in alleviating oxidative stress and cell damage during IRI by modulating oxidative stress, decreasing apoptosis and inhibiting inflammatory responses. ALDH2 exerts protective effects by detoxifying reactive aldehydes, thereby preventing lipid peroxidation and maintaining cellular homeostasis. Furthermore, ferroptosis, a regulated form of cell death driven by iron accumulation and subsequent lipid peroxidation, is a key process in IRI. However, the precise role of ALDH2 in modulating ferroptosis during IRI remains incompletely understood. Although there is an interaction between ALDH2 activity and ferroptosis, the underlying mechanisms have yet to be clarified. The present review examines the role of ALDH2 and ferroptosis in IRI and the potential regulatory influence of ALDH2 on ferroptosis mechanisms, as well as potential targeting of ALDH2 and ferroptosis for IRI treatment and prevention. By elucidating the complex interplay between ALDH2 and ferroptosis, the present review aims to provide new insights for the development of innovative therapeutic strategies to mitigate ischemic tissue damage and improve clinical outcomes.

The Evolution of Ischemia-Reperfusion Injury Research in Ischemic Stroke: Insights From a Two-Decade Bibliometric Analysis

BACKGROUND

Ischemic stroke is a complex disease with high mortality and disability rates. Ischemia-reperfusion injury is a common aftermath. There have been significant advancements in understanding ischemia-reperfusion injury in ischemic stroke over the past two decades. This study aims to evaluate the current state of ischemia-reperfusion injury in ischemic stroke through bibliometric analysis, identifying key research areas and emerging trends.

METHODS

Relevant documents in the Web of Science Core Collection, SCI-Expanded from January 1, 2003, to December 31, 2023, were downloaded on July 10, 2024. Bibliometric analysis was performed using HistCite, VOSviewer, CiteSpace, and Bibliometrics online analysis platform.

RESULTS

A total of 2179 research papers from 611 journals in 66 countries were included in this study. Among these papers, China emerged as the leading contributor of ischemia-reperfusion injury in ischemic stroke publications, with Capital Medical University standing out as the institution with the highest number of publications in this area. Y. Zhang was identified as the author with the most publications during the study period. Brain Research was found to be the most prolific journal for this research. The keywords "ferroptosis", "circular RNA", "polarization", and "fatty acid binding protein" represent the current hot spots of ischemia-reperfusion injury in ischemic stroke research.

CONCLUSION

This bibliometric analysis offers the first thorough overview of hot spots and research trends in ischemia-reperfusion injury in ischemic stroke over the previous 21 years, providing researchers with new ideas in the field. "ferroptosis", "circular RNA", "polarization", and "fatty acid binding protein" may be the focus of future studies.

Neutrophil-like cell membrane-coated metal-organic frameworks for siRNA delivery targeting NOX4 to alleviate oxidative stress in acute ischemic injury

Although reperfusion is the most effective treatment for acute ischemic stroke, it often results in serious secondary ischemia/reperfusion (I/R) injury due to oxidative stress. This oxidative stress primarily results from the overproduction of reactive oxygen species (ROS) during reperfusion which, in turn, is largely induced by high expression of NADPH oxidase 4 (NOX4). Inhibiting NOX4 gene expression has therefore been proposed as a direct approach to reduce ROS production and promote angiogenesis. Recognizing both the potential of siRNA-based therapies for selective gene silencing and the critical role of neutrophil-endothelial interactions during I/R injury, here we present a unique therapeutic approach where neutrophil-like cell membrane coated porous metal-organic framework nanoparticles are loaded with siNOX4 (M-MOF-siNOX4) and designed to target damaged brain microvascular tissue. These then mitigate oxidative stress by suppressing NOX4 expression. Using an in vitro oxygen-glucose deprivation/re-oxygenation model, we demonstrate that M-MOF-siNOX4 nanoparticles specifically bind to activated endothelial cells, effectively reducing NOX4 expression, decreasing both ROS production and cell apoptosis, and restoring cell viability. Use of an in vivo mouse model of middle cerebral artery occlusion further confirmed M-MOF-siNOX4 nanoparticles to substantially alleviate brain damage and protect neurological function following ischemic stroke. Taken together, our study presents an innovative and effective siRNA-based strategy for reducing oxidative stress in ischemic stroke therapy. STATEMENT OF SIGNIFICANCE: Ischemia/reperfusion (I/R) injury, a major complication of acute ischemic stroke, is primarily driven by oxidative stress due to the excessive production of reactive oxygen species (ROS). Current treatments targeting oxidative stress and cell death often lack specificity, leading to off-target effects. This study introduces an innovative nanoparticle-based therapy using neutrophil-like cell membrane-coated metal-organic frameworks (MOFs) to deliver siNOX4, an siRNA targeting NOX4, a key ROS-producing enzyme. This approach enhances targeted delivery, reduces ROS production and cell death, and significantly improves neurological recovery in stroke models. By overcoming the limitations of existing therapies, this strategy holds strong potential for revolutionizing ischemic stroke treatment and addressing other disorders related to oxidative stress.

Organelle interplay in cardiovascular diseases: Mechanisms, pathogenesis, and therapeutic perspectives

Cardiovascular diseases (CVDs) are the leading cause of rising morbidity and mortality among humans worldwide; however, our approach to the pathogenesis, exploration, and management of CVDs still remains limited. As the heart consists of cardiomyocytes, cardiac fibroblasts, endothelial cells, smooth muscle cells, and several types of cells, different types of dysfunction in the interplay between organelles play an important damaging role, resulting in cardiac pathologies. The interplay between cellular organelles is intricate and vital for maintaining cellular homeostasis, as highlighted by multiple diseases linked to the dysfunction of both organelles. Many studies have revealed the potential mechanisms by which organelles communicate with each other and regulate the pathological processes of CVDs together. However, gaps remain in fully understanding the complexity of these interactions and translating these insights into therapeutic approaches. In this review, we summarized how the interplay between cellular organelles in the cardiomyocytes alters in various heart diseases. We find underexplored areas, such as the crucial signaling pathways governing organelle communication, and discuss their implications for disease future progression. Furthermore, we evaluate emerging potential medicines aimed at restoring organelle interactions. Finally, we propose future directions for researching to advance the development of novel medicines and therapies, addressing current gaps and providing a theoretical basis for improved clinical outcomes in CVDs.

Rapid thawing enhances tissue destruction in a mouse model of cutaneous cryoablation: Insights into oxidative stress and neutrophil activation

BACKGROUND

Cryoablation is an integral therapeutic approach in dermatology for eliminating viral warts and benign tumors by damaging tissue through freeze-thaw cycles. Rapid thawing of the frozen area by warming it with fingertips during cryoablation is a common technique in Japan; however, its efficacy has not been elucidated.

OBJECTIVE

This study aimed to evaluate the effect of rapid thawing on cryoablation-treated skin and clarify the underlying mechanisms using cryoablation model mice.

METHODS

Cryoablation was performed on the dorsal skin of mice using a liquid nitrogen-soaked cotton swab, followed by rapid thawing by warming with fingertips or natural thawing without treatment. The effects on skin ulcers, immune cell infiltration, and oxidative stress were assessed.

RESULTS

Rapid thawing enlarged cryoablation-induced skin ulcers. The numbers of cryoablation-induced CD3+ T cells, neutrophils, neutrophil extracellular traps (NETs), and TUNEL+ cells increased with rapid thawing. Visualization of oxidative stress in OKD48 transgenic mice showed that oxidative stress signals in the cryoablation-treated area were enhanced with rapid thawing. Real-time PCR analysis of mouse skin demonstrated that cryoblation-induced levels of NOX2 and HO-1 were significantly elevated with rapid thawing. In mouse melanoma tumors treated with cryoablation, rapid thawing significantly inhibited tumor growth and increased the infiltration of neutrophils, NETs, and TUNEL+ cells compared to the group without rapid thawing.

CONCLUSION

Rapid thawing during cryoablation enhances neutrophil and lymphocyte infiltration, increases oxidative stress, and induces cell death, leading to greater tissue destruction in mice. Dermatologists should consider employing rapid thawing techniques during cryoablation when higher therapeutic intensities are required.

Mitochondrial dynamics and quality control regulate proteostasis in neuronal ischemia-reperfusion

Mitochondrial damage and dysfunction are hallmarks of neuronal injury during cerebral ischemia-reperfusion (I/R). Critical mitochondrial functions including energy production and cell signaling are perturbed during I/R, often exacerbating damage and contributing to secondary injury. The integrity of the mitochondrial proteome is essential for efficient function. Mitochondrial proteostasis is mediated by the cooperative forces of mitophagy and intramitochondrial proteolysis. The aim of this study was to elucidate the patterns of mitochondrial protein dynamics and their key regulators during an in vitro model of neuronal I/R injury. Utilizing the MitoTimer reporter, we quantified mitochondrial protein oxidation and turnover during I/R injury, highlighting a key point at 2 h reoxygenation for aged/oxidized protein turnover. This turnover was found to be mediated by both LONP1-dependent proteolysis and PRKN/parkin-dependent mitophagy. Additionally, the proteostatic response of neuronal mitochondria is influenced by both mitochondrial fusion and fission machinery. Our findings highlight the involvement of both mitophagy and intramitochondrial proteolysis in the response to I/R injury.Abbreviations: cKO: conditional knockout; CLPP: caseinolytic mitochondrial matrix peptidase proteolytic subunit; DIV: days in vitro; DNM1L/DRP1: dynamin 1 like; ETC: electron transport chain; hR: hours after reoxygenation; I/R: ischemia-reperfusion; LONP1: lon peptidase 1, mitochondrial; mtUPR: mitochondrial unfolded protein response; OGD: oxygen glucose deprivation; OGD/R: oxygen glucose deprivation and reoxygenation; OPA1: OPA1 mitochondrial dynamin like GTPase; PINK1: PTEN induced kinase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; ROI: region of interest; WT: wild-type.

Lactylation: a promising therapeutic target in ischemia-reperfusion injury management

Ischemia-reperfusion injury (IRI) is a critical condition that poses a significant threat to patient safety. The production of lactate increases during the process of IRI, and lactate serves as a crucial indicator for assessing the severity of such injury. Lactylation, a newly discovered post-translational modification in 2019, is induced by lactic acid and predominantly occurs on lysine residues of histone or nonhistone proteins. Extensive studies have demonstrated the pivotal role of lactylation in the pathogenesis and progression of various diseases, including melanoma, myocardial infarction, hepatocellular carcinoma, Alzheimer's disease, and nonalcoholic fatty liver disease. Additionally, a marked correlation between lactylation and inflammation has been observed. This article provides a comprehensive review of the mechanism underlying lactylation in IRI to establish a theoretical foundation for better understanding the interplay between lactylation and IRI.

MSCs act as biopatches for blood-retinal barrier preservation to enhance functional recovery after retinal I/R

Retinal ischemia/reperfusion (I/R) is one of the most common pathologies of many vision-threatening diseases and is caused by blood-retinal barrier (BRB) breakdown and the resulting inflammatory infiltration. Targeting BRB is promising for retinal I/R treatment. Mesenchymal stromal cells (MSCs) are emerging as novel therapeutic strategies. Although intravitreal injection targets the retina, the restricted number of injected cells still requires the precise biodistribution of MSCs near the injury site. Here, we found that retinal I/R led to BRB breakdown, which induced protein and cell leakage from the circulation. Retinal cell death and diminished visual function were subsequently detected. Moreover, the expression of the chemokine CCL5 increased after retinal I/R, and CCL5 colocalized with the BRB. We then overexpressed CCR5 in human induced pluripotent stem cell-derived MSCs (iMSCs). In vivo, intravitreal-injected iMSCCCR5 preferentially migrated and directly integrated into the BRB, which preferably restored BRB integrity and eventually promoted retinal function recovery after retinal I/R. In summary, our work suggested that iMSCs act as biopatches for BRB preservation and that iMSC-based therapy is a promising therapeutic approach for retinal diseases related to I/R.

Exosome-Based Therapy in Cardiovascular Diseases: A New Frontier in Cardiovascular Disease Treatment

Exosomes, small extracellular vesicles ranging from 30 to 150 nanometers in diameter, have emerged as pivotal mediators of intercellular communication. These vesicles, originally perceived as cellular debris, are now recognized for their intricate roles in transporting bioactive molecules, including proteins, lipids, and nucleic acids, between cells. Exosomes have received considerable attention due to their roles in diverse physiological and pathological processes, especially in relation to cardiovascular diseases (CVDs). CVDs are intricately linked, sharing common risk factors and pathological mechanisms, such as inflammation, oxidative stress, and endothelial dysfunction. Exosomes have been implicated in either directly or indirectly influencing these phenomena. They are secreted by virtually all cell types, including endothelial cells, cardiomyocytes, and stem cells, play critical roles in maintaining vascular homeostasis and responding to pathological stimuli. Their capacity to traverse biological barriers, maintain stability in circulation, and effectively encapsulate and deliver a variety of molecular cargos makes them promising candidates for both biomarkers and therapeutic agents. This review aims to explore the multifaceted roles of exosomes in CVDs. And we will discuss the mechanisms of exosome biogenesis and release, their molecular composition, and the ways in which they contribute to disease pathophysiology. Additionally, we will emphasize the potential of exosomes as diagnostic biomarkers and their therapeutic uses, highlighting their significance in the advancement of innovative treatment strategies. This review explores recent findings and advancements in exosome research, emphasizing their significance in CVD and paving the way for future studies and clinical applications.

Different types of cell death and their interactions in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion (I/R) injury is a multifaceted process observed in patients with coronary artery disease when blood flow is restored to the heart tissue following ischemia-induced damage. Cardiomyocyte cell death, particularly through apoptosis, necroptosis, autophagy, pyroptosis, and ferroptosis, is pivotal in myocardial I/R injury. Preventing cell death during the process of I/R is vital for improving ischemic cardiomyopathy. These multiple forms of cell death can occur simultaneously, interact with each other, and contribute to the complexity of myocardial I/R injury. In this review, we aim to provide a comprehensive summary of the key molecular mechanisms and regulatory patterns involved in these five types of cell death in myocardial I/R injury. We will also discuss the crosstalk and intricate interactions among these mechanisms, highlighting the interplay between different types of cell death. Furthermore, we will explore specific molecules or targets that participate in different cell death pathways and elucidate their mechanisms of action. It is important to note that manipulating the molecules or targets involved in distinct cell death processes may have a significant impact on reducing myocardial I/R injury. By enhancing researchers' understanding of the mechanisms and interactions among different types of cell death in myocardial I/R injury, this review aims to pave the way for the development of novel interventions for cardio-protection in patients affected by myocardial I/R injury.

Marine mussel metabolism under stress: Dual effects of nanoplastics and coastal hypoxia

Emerging challenges in marine environments include nanoplastics (NPs) pollution and coastal hypoxia. Although NPs toxicity in marine organisms is being increasingly documented, the complex interactions between coastal hypoxia and NPs remain largely unexplored. This study investigated the dual effects of polystyrene nanoplastics and different oxygen levels on redox homeostasis and bioenergetics in the marine model organism Mytilus galloprovincialis. Both NPs and hypoxia significantly disrupted redox homeostasis in mussels. Exposure to NPs alone increased electron transport chain activity, whereas exposure to hypoxia alone and co-exposure significantly reduced this activity. Metabolomic analysis showed that NPs primarily affected the pentose phosphate pathway (PPP), tricarboxylic acid (TCA) cycle, and amino acid metabolism; hypoxia exposure alone disrupted the TCA cycle, pyruvate metabolism, and glycolysis/gluconeogenesis, whereas combined exposure notably altered the TCA cycle, PPP, and sugar interconversion. This suggests that regulating these pathways would help mussels cope with the combined environmental stress. Furthermore, co-exposure severely disrupted redox homeostasis and energy metabolism in mussels, suggesting that hypoxia exacerbates NPs toxicity. We believe that these new findings would enhance our understanding of the compounded ecological risks posed by NPs in the context of climate change.

Sunitinib's Effect on Bilateral Optic Nerve Damage in Rats Following the Unilateral Clamping and Unclamping of the Common Carotid Artery

Background/objectives: Common carotid artery occlusion can cause oxidant and inflammatory damage to the optic nerve. In this study, the effect of sunitinib was investigated, the antioxidant and anti-inflammatory properties of which have been previously reported and shown to be protective in I/R injury and in preventing bilateral optic nerve ischemia-reperfusion (I/R) injuries after unilateral common carotid artery ligation in rats. Methods: In this study, 18 Albino Wistar male rats were divided into SG (sham-operated), CCU (clamping and unclamping), and SCCU (sunitinib + clamping and unclamping) groups. One hour before the surgical procedures, sunitinib (25 mg/kg, oral) was given to SCCU rats. Anesthesia was induced with ketamine (60 mg/kg, ip) and sevoflurane. The right common carotid arteries of all rats were accessed under anesthesia. While the skin opened in SG rats was closed with sutures, the right common carotid arteries of CCU and SCCU rats were clipped, and an ischemia period was created for 10 min. Then, reperfusion (6 h) was achieved by unclipping. After euthanasia with ketamine (120 mg/kg, intraperitoneally), the right and left optic nerves of the rats were removed and examined biochemically and histopathologically. Results: Malondialdehyde, tumor necrosis factor α, interleukin-1β, and interleukin-6 were increased, and total glutathione levels had decreased in both ipsilateral and contralateral optic nerves (p < 0.05). These changes were more prominent on the ipsilateral side. Similarly, histopathological damage was observed to be more on the ipsilateral side (p < 0.05). Biochemical and histopathological changes were significantly suppressed in rats receiving sunitinib treatment (p < 0.05). Conclusions: Sunitinib may protect optic nerve tissue against I/R injury by reducing oxidative stress and inflammation.

Ultrasound-mediated nanomaterials for the treatment of inflammatory diseases

Sterile and infection-associated inflammatory diseases are becoming increasingly prevalent worldwide. Conventional drug therapies often entail significant drawbacks, such as the risk of drug overdose, the development of drug resistance in pathogens, and systemic adverse reactions, all of which can undermine the effectiveness of treatments for these conditions. Nanomaterials (NMs) have emerged as a promising tool in the treatment of inflammatory diseases due to their precise targeting capabilities, tunable characteristics, and responsiveness to external stimuli. Ultrasound (US), a non-invasive and effective treatment method, has been explored in combination with NMs to achieve enhanced therapeutic outcomes. This review provides a comprehensive overview of the recent advances in the use of US-mediated NMs for treating inflammatory diseases. A comprehensive introduction to the application and classification of US was first presented, emphasizing the advantages of US-mediated NMs and the mechanisms through which US and NMs interact to enhance anti-inflammatory therapy. Subsequently, specific applications of US-mediated NMs in sterile and infection-associated inflammation were summarized. Finally, the challenges and prospects of US-mediated NMs in clinical translation were discussed, along with an outline of future research directions. This review aims to provide insights to guide the development and improvement of US-mediated NMs for more effective therapeutic interventions in inflammatory diseases.

Amide proton transfer MRI may reflect effective reperfusion and predict functional outcomes in patients with ischemic stroke

Perfusion imaging is useful to assess tissue recovery in patients with acute ischemic stroke (AIS); however, it cannot reflect tissue metabolism. We postulated that amide proton transfer (APT) imaging can characterize the tissue status after reperfusion therapy, thus providing prognostic value for 90-day functional outcomes. We included 63 patients with AIS and large-vessel occlusion (LVO). The APT signals, including APT# and NOE# (nuclear Overhauser enhancement) were quantified. Ischemic lesions observed on APT# and diffusion-weighted imaging (DWI) were classified according to their mismatch patterns (APT# < DWI; APT# ≥ DWI). Predictors of 90-day good outcomes (modified Rankin scale score 0-2) were evaluated. Patients with successful reperfusion exhibited higher APT#, smaller percentage change of APT#, and a greater likelihood of presenting APT# < DWI compared to those with poor reperfusion (all P < 0.05). The APT# (odds ratio [OR] = 11.48, P = 0.046) and a mismatch pattern of APT# < DWI (OR = 7.41, P = 0.020) independently predicted good outcomes besides the clinical parameters. A mismatch pattern of APT# ≥ DWI was a significant marker of poor outcomes despite successful reperfusion (P = 0.002). Our study provides preliminary evidence that APT may reveal tissue recovery after reperfusion and predict good outcomes at 90 days in patients with AIS and LVO.

Plasma inflammatory and angiogenic protein profiling of patients with sickle cell disease

In this study, we aimed to explore the inflammatory and angiogenic pathways in sickle cell disease (SCD). We used proximity extension assay technology (Olink) to measure 92 plasma proteins involved in inflammation and angiogenesis. Plasma samples were collected from 57 SCD patients (sickle cell anaemia/HbS-β0 thalassaemia-thalassaemia) in steady-state and 13 healthy ethnicity-matched healthy controls (HCs). From 15 patients, paired samples were collected during both steady-state and vaso-occlusive episodes (VOEs) and from 23 SCD patients longitudinal samples were collected before and after treatment with either voxelotor (n = 10), hydroxyurea (n = 8) or allogeneic haematopoietic stem-cell transplantation (n = 5). Fifty plasma proteins were differentially expressed in steady-state SCD patients as compared to HC. These included proteins involved in angiogenesis (i.e. ANGPT1, ANGPT2 and VEGFA), the IL-18 signalling pathway (i.e. IL-6, IL-10, IL-18), T-cell activation (i.e. LAG3, PDCD1) and natural killer (NK)-cell activation (CD244, NCR1, GZMB). While proteins involved in angiogenesis and the IL-18 signalling pathway were further upregulated during VOE, levels of several proteins involved in the IL-18 pathway, T-cell and NK-cell activation and angiogenesis, restored towards levels detected in HCs after curative or disease-modifying treatment. These findings might contribute to a better understanding of SCD pathophysiology and identifying potential new targets for therapeutic interventions.

Zn2+ protects H9C2 cardiomyocytes by alleviating MAMs-associated apoptosis and calcium signaling dysregulation

PURPOSE

This study aims to investigate whether zinc ion (Zn2+) alleviates myocardial ischemia-reperfusion injury (MIRI) through the MAM-associated signaling pathway and to explore its impact on ERS and calcium overload.

METHODS

H9C2 cells were cultured in a DMEM supplemented with 10 % fetal bovine serum and 1 % antibiotic solution. A MIRI model was established through simulated ischemia and reoxygenation with Zn2+ treatment in a complete medium. Cells were then treated with the MCU inhibitor ruthenium red (RR), the MCU activator spermine (SP), and siRNAs targeting Bap31, MCU, VDAC1, and FUNDC1. Cell viability was assessed using MTT and CCK-8 assays. Lactate dehydrogenase (LDH) levels were measured with a commercial kit. Western blot was performed to detect protein expression levels. Cell apoptosis, intracellular zinc, calcium levels, mitochondrial membrane potential, and protein fluorescence changes were observed using laser scanning confocal microscopy.

RESULTS

Compared to the control group, cell viability was significantly reduced in the I/R group, accompanied by increased expression of apoptosis and calcium overload-related proteins increased cell injury, apoptosis, calcium overload, and a decrease in mitochondrial membrane potential. Zn2+ treatment reversed the detrimental effects of I/R in the I/R + Zn2+ group. When Bap31, VDAC1, FUNDC1, or MCU were silenced using siRNA, the protective effect of Zn2+ was further enhanced (P < 0.05).

CONCLUSIONS

Ischemia-reperfusion (I/R) leads to cardiomyocyte injury and apoptosis. Zn2+ downregulates the expression of key apoptotic proteins through the Bap31/Fis1 pathway and regulates MCU activity through the IP3R1-GRP75-VDAC1 and IP3R2/FUNDC1 pathways to alleviate calcium overload and ultimately protect cardiomyocytes after I/R.

Is Reperfusion Injury a Largely Intra-Ischemic Injury?

Reperfusion injury (RI) refers to an array of detrimental cellular and biochemical processes that are widely believed to be triggered by reperfusion following focal cerebral ischemia and to contribute to infarct extension and poor outcome despite complete recanalization. Accordingly, it is widely recommended that therapies targeting RI be administered after recanalization. The present topical review demonstrates, however, that the vast majority of, and possibly all, processes considered part of RI are not actually provoked by reperfusion but develop during the ischemic phase. This notion has significant implications for clinical trials. Thus, for optimal efficacy, treatments targeting RI should accordingly be started before recanalization. Conversely, interventions aimed at protecting the ischemic penumbra, either pharmacological or nonpharmacological, during arterial occlusion are likely to also benefit RI-related processes and should probably be continued after recanalization. Overall, that RI is largely an intra-ischemic process has important ramifications for drug development as well as clinical trials, and more broadly for the management of hyperacute ischemic stroke patients prior to, and following, recanalization.

Radiofrequency electromagnetic field ınhibits HIF-1 alpha and activates eNOS signaling to prevent intestinal damage in a model of mesenteric artery ischemia in rats

Background: Pathologies such as mesenteric artery ischemia and reperfusion (MIR) can lead to many organ dysfunctions, including the brain and heart through damage mechanisms induced in response to hypoxic conditions. Radiofrequency electromagnetic field (RF-EMF) can increase the vascularization of tissues by providing endothelial nitric oxide synthase (eNOS)-mediated nitric oxide (NO) release from the endothelium. The aim of this study is to investigate the protective effect and mechanism of RF-EMF in ischemic intestinal injury in the experimental MIR model. Methods: In the study, 32 Wistar Albino rats were divided into four groups: Sham group, MIR group, Prophylactic (Pr) RF-EMF + MIR group, MIR + Therapeutic (Tr) RF-EMF group. At the end of the experimental phase, after sacrifice, blood samples and the 10 cm terminal ileum part of the intestinal tissues was cut and collected for histopathological, immunohistochemical, genetic and biochemical analyses. Results: In the MIR group, Cas-3, TNF-α, VEGF, BAX and HIF-1α expressions increased, while OSI levels, and PCNA, BCL2 and eNOS expressions decreased. In addition marked hyperemia, hemorrhage, edema, inflammatory cell infiltrations, and erosion or ulcers were observed in MIR group. Pr (especially in eNOS expression) and Tr (especially in pathological findings) treatment of RF-EMF reversed all these parameters but more effective recovery was observed in Tr treated group. Conclusion: RF-EMF-treatment preserved the vascularization of the tissue and decreased hypoxia-induced oxidative stress, inflammation, and apoptosis.

Pharmacological modulation of PI3K/PTEN/Akt/mTOR/ERK signaling pathways in ischemic injury: a mechanistic perspective

Ischemia, also known as ischemia, relates to the reduced blood movement to a cells, muscle group, or organ in the body, culminating in an insufficient amount of oxygen required for cellular metabolism and the maintenance of tissue viability. There are different types of stroke (ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage), and different causes of stroke (e.g., cardioembolic, atherothrombotic, lacunar ischemic strokes, aneurysmal subarachnoid hemorrhage). It also includes other disorders affecting the blood vessels in the brain (e.g., vascular malformations, unruptured aneurysms). Each of these conditions has different characteristics in terms of how common they are and how they are managed. Stroke is the primary and catastrophic clinical presentation of all cerebrovascular diseases. In this review we focused about the importance of PI3K/AKT signaling pathways which are important in the onset of ischemia-reperfusion (I/R) injury. In addition, mTOR, a target that is activated by the PI3K/Akt signaling pathway, is both required and capable of providing enough protection to the heart against harm caused by I/R. Moreover, the signaling pathways that involve PI3K/Akt/Erk/PTEN/mTOR play a crucial role in facilitating the proliferation and maintenance of neurons following an ischemic stroke. The current review summarizes the molecular mechanisms of various signaling pathways in ischemic diseases and suggests targeting its receptors as a preventive approach based on pre-clinical and clinical studies.

Genome-wide KAS-Seq mapping of leukocytes in ischemia-reperfusion model reveals IL7R as a potential therapeutic target for ischemia-reperfusion injury

Ischemia-reperfusion injury (IRI) is one of the leading causes of mortality and disability worldwide. Owing to its complex pathogenesis, there is still a lack of effective therapeutic targets in clinical practice, and exploring the mechanism and targets of IRI is still a major clinical challenge. This study aimed to explore the genetic alterations in leukocytes in peripheral blood after ischemia-reperfusion, aiming to discover new biomarkers and potential therapeutic targets. KAS-Seq (Kethoxal-assisted single-strand DNA sequencing) was used to obtain gene expression profiles of circulating leukocytes in a porcine ischemia-reperfusion model at 24, 48, and 72 h post-ischemia‒reperfusion. This method integrated genes that exhibited regular changes over time. In this study, we thoroughly analyzed the dynamic changes in gene expression post-IRI, revealing significant enrichment in key signaling pathways that regulate immune responses and T-cell activation over time. Our identification of the interleukin-7 receptor (IL7R) was particularly striking, as it plays a crucial molecular role in IRI. Additionally, using database mining technology, we confirmed the close relationship between IL7R and IRI, explored the interaction between interferon-γ (IFNG) and IL7R in T-cell activation, and clarified their joint influence on ischemia-reperfusion injury. Using KAS-Seq analysis of leukocytes from peripheral blood, we successfully delineated the temporal patterns of gene expression and changes in signal transduction pathways in porcine models of ischemia-reperfusion. Subsequent in-depth analysis identified IL7R as a potential novel therapeutic target for IRI. The pivotal role of this gene in modulating immune responses provides innovative avenues for the development of IRI treatments.

Short-term fasting before living kidney donation has an immune-modulatory effect

Background

Short-Term Fasting (STF) is an intervention reducing the intake of calories, without causing undernutrition or micronutrient-related malnutrition. It aims to systemically improve resilience against acute stress. Several (pre-)clinical studies have suggested protective effects of STF, marking the systemic effects STF can induce in respect to surgery and ischemia-reperfusion injury. In addition, STF also affects the number of circulating immune cells. We aim to determine the effect of STF on the abundance and phenotype of different immune cell populations.

Methods

Thirty participants were randomly selected from the FAST clinical trial, including living kidney donors, randomized to an STF-diet or control arm. In an observational cohort sub-study we prospectively included 30 patients who donated blood samples repeatedly during study runtime. Using flow cytometry analyses, immune cell phenotyping was performed on peripheral blood mononuclear cells. Three panels were designed to investigate the presence and activation status of peripheral T cells, B cells, dendritic cells (DCs) and myeloid cells.

Results

Eight participants were excluded due to sample constraints. Baseline characteristics showed no significant differences, except for fasting duration. Weight changes were minimal and non-significant across different time intervals, with slight trends toward long-term weight loss pre-surgery. Glucose, insulin, and β-hydroxybutyrate levels differed significantly between groups, reflecting adherence to the fasting diet. Flow cytometry and RNA sequencing analysis revealed no baseline differences between groups, with high variability within each group. STF changes the levels and phenotype of immune cells, reducing the abundance and activation of T cells, including regulatory T cells, increased presence of (naïve) B cells, and elevation of type 1 conventional DCs (cDC1s). In addition, a decrease in central memory T cells was observed.

Discussion

In this study, we observed significant changes due to fasting in B cells, T cells, and DCs, specifically toward less specialized lymphocytes, suggesting an arrest in B and T cell development. Further research should focus on the clinical implications of changes in immune cells and significance of these observed immunological changes.

Conclusion

STF results in reduced numbers and activation status of T cells and Tregs, increased presence of (naïve) B cells, and elevation of cDC1s.

Inhibition of mir-155-5p alleviates cardiomyocyte pyroptosis induced by hypoxia/reoxygenation via targeting SIRT1-mediated activation of the NLRP3 inflammasome

OBJECTIVE

The hypoxia/reoxygenation (H/R)-induced pyroptosis of cardiomyocytes plays a crucial role in the pathogenesis of myocardial infarction (MI). miR-155-5p represents a promising target for MI therapy. However, its involvement in H/R-induced pyroptosis remains unclear.

METHODS

The H/R exposed rat cardiomyocyte H9c2 was utilized as in vitro model, and the expression levels of miR-155-5p and SIRT1 in cells were modulated through cell transfection experiments. Cell proliferative activity was assessed using the Cell counting kit-8 assay. Supernatant lactate dehydrogenase (LDH) activity was determined through colorimetry. The levels of living and dead cell were observed via Calcin-AM/PI staining. Levels of supernatant interleukin (IL)-1β and IL-18 were measured using ELISA assay. The expression levels of miR-155-5p and silent information regulator 1 (SIRT1) mRNA were detected by qRT-PCR. The protein expression levels of SIRT1, NLRP3, N-terminal gasdermin D (GSDMD-N), and Cleaved caspase-1 were evaluated using Western blot analysis. The targeted regulatory relationship between miR-155-5p and SIRT1 was verified using dual luciferase reporter gene assay.

RESULTS

The proliferation activity of H9c2 cells induced by H/R was attenuated, accompanied by severe injury, increased cell death, and the release of a substantial amount of pro-inflammatory cytokines IL-1β and IL-18. In addition, H/R stimulation resulted in the upregulation of miR-155-5p expression and downregulation of SIRT1 expression in H9c2 cells. Suppression of miR-155-5p or overexpression of SIRT1 exhibited ameliorative effects on H/R-induced cellular injury in H9c2 cells and inhibited NLRP3 inflammasome-mediated pyroptosis. The dual-luciferase assay confirmed the direct targeting of SIRT1 by miR-155-5p in H9c2 cells. Furthermore, partial reversal of the inhibitory effect of miR-155-5p inhibitor on H/R-induced NLRP3 inflammasome-mediated pyroptosis in H9c2 cells was observed upon interference with SIRT1 expression.

CONCLUSION

Inhibition of miR-155-5p alleviates cardiomyocyte pyroptosis induced by H/R via targeting SIRT1-mediated activation of the NLRP3 inflammasome.

Caveolin and oxidative stress in cardiac pathology

Caveolins interact with signaling molecules within caveolae and subcellular membranes. Dysregulation of caveolin function and protein abundance contributes to cardiac pathophysiological processes, driving the development and progression of heart disease. Reactive oxygen species (ROS) play a critical role in maintaining cellular homeostasis and are key contributors to the pathophysiological mechanisms of cardiovascular disorders. Caveolins have been shown to modulate oxidative stress and regulate redox homeostasis. However, the specific roles of caveolins, particularly caveolin-1 and caveolin-3, in regulating ROS production during cardiac pathology remain unclear. This mini-review article highlights the correlation between caveolins and oxidative stress in maintaining cardiovascular health and modulating cardiac diseases, specifically in myocardial ischemia, heart failure, diabetes-induced metabolic cardiomyopathy, and septic cardiomyopathy. A deeper understanding of caveolin-mediated mechanisms may pave the way for innovative therapeutic approaches to treat cardiovascular diseases.

Protective Effects of BPC 157 on Liver, Kidney, and Lung Distant Organ Damage in Rats with Experimental Lower-Extremity Ischemia-Reperfusion Injury

Background and Objectives: Ischemia-reperfusion (I/R) injury can affect multiple distant organs following I/R in the lower extremities. BPC-157's anti-inflammatory and free radical-neutralizing properties suggest its potential in mitigating ischemia-reperfusion damage. This study evaluates the protective effects of BPC-157 on remote organ damage, including the kidneys, liver, and lungs, in a rat model of skeletal muscle I/R injury. Materials and Methods: A total of 24 male Wistar albino rats were randomly divided into four groups: sham (S), BPC-157(B), lower extremity I/R(IR) and lower extremity I/R+BPC-157(I/RB). Some 45 min of ischemia of lower extremity was followed by 2 h of reperfusion of limbs. BPC-157 was applied to groups B and I/RB at the beginning of the procedure. After 2 h of reperfusion, liver, kidney and lung tissues were harvested for biochemical and histopathological analyses. Results: In the histopathological examination, vascular and glomerular vacuolization, tubular dilation, hyaline casts, and tubular cell shedding in renal tissue were significantly lower in the I/RB group compared to other groups. Lung tissue showed reduced interstitial edema, alveolar congestion, and total damage scores in the I/RB group. Similarly, in liver tissue, sinusoidal dilation, necrotic cells, and mononuclear cell infiltration were significantly lower in the I/RB group. Additionally, the evaluation of TAS, TOS, OSI, and PON-1 revealed a statistically significant increase in antioxidant activity in the liver, lung, and kidney tissues of the I/RB group. Conclusions: The findings of this study demonstrate that BPC-157 exerts a significant protective effect against distant organ damage in the liver, kidneys, and lungs following lower extremity ischemia-reperfusion injury in rats.

A novel anti-ischemic stroke candidate drug AAPB with dual effects of neuroprotection and cerebral blood flow improvement

Ischemic stroke (IS) is a globally life-threatening disease. Presently, few therapeutic medicines are available for treating IS, and rt-PA is the only drug approved by the US Food and Drug Administration (FDA) in the US. In fact, many agents showing excellent neuroprotection but no blood flow-improving activity in animals have not achieved ideal clinical efficacy, while thrombolytic drugs only improving blood flow without neuroprotection have limited their wider application. To address these challenges and meet the huge unmet clinical need, we have designed and identified a novel compound AAPB with dual effects of neuroprotection and cerebral blood flow improvement. AAPB significantly reduced cerebral infarction and neural function deficit in tMCAO rats, pMCAO rats, and IS rhesus monkeys, as well as displayed exceptional safety profiles and excellent pharmacokinetic properties in rats and dogs. AAPB has now entered phase I of clinical trials fighting IS in China.

Regulated cell death in acute myocardial infarction: Molecular mechanisms and therapeutic implications

Acute myocardial infarction (AMI), primarily caused by coronary atherosclerosis, initiates a series of events that culminate in the obstruction of coronary arteries, resulting in severe myocardial ischemia and hypoxia. The subsequent myocardial ischemia/reperfusion (I/R) injury further aggravates cardiac damage, leading to a decline in heart function and the risk of life-threatening complications. The complex interplay of multiple regulated cell death (RCD) pathways plays a pivotal role in the pathogenesis of AMI. Each RCD pathway is orchestrated by a symphony of molecular regulatory mechanisms, highlighting the dynamic changes and critical roles of key effector molecules. Strategic disruption or inhibition of these molecular targets offers a tantalizing prospect for mitigating or even averting the onset of RCD, thereby limiting the extensive loss of cardiomyocytes and the progression of detrimental myocardial fibrosis. This review systematically summarizes the mechanisms underlying various forms of RCD, provides an in-depth exploration of the pathogenesis of AMI through the lens of RCD, and highlights a range of promising therapeutic targets that hold the potential to revolutionize the management of AMI.

Essential role of sulfide oxidation in brain health and neurological disorders

Hydrogen sulfide (H2S) is an environmental hazard well known for its neurotoxicity. In mammalian cells, H2S is predominantly generated by transsulfuration pathway enzymes. In addition, H2S produced by gut microbiome significantly contributes to the total sulfide burden in the body. Although low levels of H2S is believed to exert various physiological functions such as neurotransmission and vasomotor control, elevated levels of H2S inhibit the activity of cytochrome c oxidase (i.e., mitochondrial complex IV), thereby impairing oxidative phosphorylation. To protect the electron transport chain from respiratory poisoning by H2S, the compound is actively oxidized to form persulfides and polysulfides by a mitochondrial resident sulfide oxidation pathway. The reaction, catalyzed by sulfide:quinone oxidoreductase (SQOR), is the initial and critical step in sulfide oxidation. The persulfide species are subsequently oxidized to sulfite, thiosulfate, and sulfate by persulfide dioxygenase (ETHE1 or SDO), thiosulfate sulfurtransferase (TST), and sulfite oxidase (SUOX). While SQOR is abundantly expressed in the colon, liver, lung, and skeletal muscle, its expression is notably low in the brains of most mammals. Consequently, the brain's limited capacity to oxidize H2S renders it particularly sensitive to the deleterious effects of H2S accumulation. Impaired sulfide oxidation can lead to fatal encephalopathy, and the overproduction of H2S has been implicated in the developmental delays observed in Down syndrome. Our recent findings indicate that the brain's limited capacity to oxidize sulfide exacerbates its sensitivity to oxygen deprivation. The beneficial effects of sulfide oxidation are likely to be mediated not only by the detoxification of H2S but also by the formation of persulfide, which exerts cytoprotective effects through multiple mechanisms. Therefore, pharmacological agents designed to scavenge H2S and/or enhance persulfide levels may offer therapeutic potential against neurological disorders characterized by impaired or insufficient sulfide oxidation or excessive H2S production.

Role of natural products in cardiovascular disease

As the world's aging population increases, cardiovascular diseases (CVDs) associated with aging deserve increasing attention. CVD in association with age is considered a major cause of morbidity and mortality worldwide. In this review, we provide an overview of the key molecular pathways, cellular processes such as autophagy, oxidative stress, inflammatory responses, myocardial remodeling and ischemia-refocused injury that accompany CVD as well as the natural products of targeting these mechanisms and some of the dietary habits that have been studied in cardiovascular-related diseases. The potential preventive and therapeutic avenues resulting from these dietary habits and natural products related to animal models and clinical studies can help us to better understand the processes involved in cardiovascular diseases and provide recommendations to reduce the cardiovascular burden associated with aging heart.

Mitochondrial complex-1 as a therapeutic target for cardiac diseases

Mitochondrial dysfunction is critical for the development and progression of cardiovascular diseases (CVDs). Complex-1 (CI) is an essential component of the mitochondrial electron transport chain that participates in oxidative phosphorylation and energy production. CI is the largest multisubunit complex (~ 1 Mda) and comprises 45 protein subunits encoded by seven mt-DNA genes and 38 nuclear genes. These subunits function as the enzyme nicotinamide adenine dinucleotide  hydrogen (NADH): ubiquinone oxidoreductase. CI dysregulation has been implicated in various CVDs, including heart failure, ischemic heart disease, pressure overload, hypertrophy, and cardiomyopathy. Several studies demonstrated that impaired CI function contributes to increased oxidative stress, altered calcium homeostasis, and mitochondrial DNA damage in cardiac cells, leading to cardiomyocyte dysfunction and apoptosis. CI dysfunction has been associated with endothelial dysfunction, inflammation, and vascular remodeling, critical processes in developing atherosclerosis and hypertension. Although CI is crucial in physiological and pathological conditions, no potential therapeutics targeting CI are available to treat CVDs. We believe that a lack of understanding of CI's precise mechanisms and contributions to CVDs limits the development of therapeutic strategies. In this review, we comprehensively analyze the role of CI in cardiovascular health and disease to shed light on its potential therapeutic target role in CVDs.

Free radicals and their impact on health and antioxidant defenses: a review

Free radicals, characterized by the presence of unpaired electrons, are highly reactive species that play a significant role in human health. These molecules can be generated through various endogenous processes, such as mitochondrial respiration and immune cell activation, as well as exogenous sources, including radiation, pollution, and smoking. While free radicals are essential for certain physiological processes, such as cell signaling and immune defense, their overproduction can disrupt the delicate balance between oxidants and antioxidants, leading to oxidative stress. Oxidative stress results in the damage of critical biomolecules like DNA, proteins, and lipids, contributing to the pathogenesis of various diseases. Chronic conditions such as cancer, cardiovascular diseases, neurodegenerative disorders, and inflammatory diseases have been strongly associated with the harmful effects of free radicals. This review provides a comprehensive overview of the characteristics and types of free radicals, their mechanisms of formation, and biological impacts. Additionally, we explore natural compounds and extracts studied for their antioxidant properties, offering potential therapeutic avenues for managing free radical-induced damage. Future research directions are also discussed to advance our understanding and treatment of free radical-associated diseases.

Inhibition of RIPK1 or RIPK3 kinase activity post ischemia-reperfusion reduces the development of chronic kidney injury

Ischemia-reperfusion injury (IRI) occurs when the blood supply to an organ is temporarily reduced and then restored. Kidney IRI is a form of acute kidney injury (AKI), which often progresses to kidney fibrosis. Necroptosis is a regulated necrosis pathway that has been implicated in kidney IRI. Necroptotic cell death involves the recruitment of the RIPK1 and RIPK3 kinases and the activation of the terminal effector, the mixed lineage kinase domain-like (MLKL) pseudokinase. Phosphorylated MLKL causes cell death by plasma membrane rupture, driving 'necroinflammation'. Owing to their apical role in the pathway, RIPK1 and RIPK3 have been implicated in the development of kidney fibrosis. Here, we used a mouse model of unilateral kidney IRI to assess whether the inhibition of RIPK1 or RIPK3 kinase activity reduces AKI and the progression to kidney fibrosis. Mice treated with the RIPK1 inhibitor Nec-1s, either before or after IR, showed reduced kidney injury at 24 hr compared with controls, whereas no protection was offered by the RIPK3 inhibitor GSK´872. In contrast, treatment with either inhibitor from days 3 to 9 post-IR reduced the degree of kidney fibrosis at day 28. These findings further support the role of necroptosis in IRI and provide important validation for the contribution of both RIPK1 and RIPK3 catalytic activities in the progression of kidney fibrosis. Targeting the necroptosis pathway could be a promising therapeutic strategy to mitigate kidney disease following IR.

Calcium phosphate formation and deposition in ischemic neurons

Ischemic stroke causes acute brain calcium phosphate (CaP) deposition, a process involving primarily the injured neurons. Whereas the adverse impact of CaP deposition on the brain structure and function has been recognized, the underlying mechanisms remain poorly understood. This investigation demonstrated that the neuron-expressed, plasma membrane-associated Ca2+-binding proteins annexin (Anx) A2, AnxA5, AnxA6, and AnxA7 contributed to neuronal CaP deposition in the mouse model of ischemic stroke. These Anxs were released from the degraded plasma membrane of the ischemic neurons and were able to form Anx/CaP complexes, a nanostructure capable of binding to the β actin filaments via Anx-actin interaction to cause neuronal CaP deposition prior to brain infarction. Anx administration to the healthy mouse brain caused brain CaP deposition and infarction. Monomeric β actin was able to block competitively Anx binding to β actin filaments and prevent ischemic stroke- and Anx administration-induced brain CaP deposition and infarction. Administration of siRNAs specific to the four Anx mRNAs alleviated brain CaP deposition and infarction. These observations support the role of Anxs in CaP formation and deposition in ischemic neurons.

The temporal relationship between mitochondrial quality and renal tissue recovery following ischemia-reperfusion injury

Background

Growing evidence indicates that disruptions in mitochondrial quality management contribute to the development of acute kidney injury (AKI), incomplete or maladaptive kidney repair, and chronic kidney disease. However, the temporal dynamics of mitochondrial quality control alterations in relation to renal injury and its recovery remain poorly understood and are addressed in this manuscript.

Method

ology: Male Wistar rats (n = 60) were subjected to varying durations of ischemia and reperfusion. Ischemia was instigated by clamping both renal arteries and for reperfusion, the clamps were removed to restore the blood flow. Renal injury, physiological function, mitochondrial assessment, and cellular mediators were analyzed.

Results

Prolonging ischemia duration reduces bioenergetic function while disrupting the balance of mitochondrial fusion, fission, and mitophagy at the gene expression level while maintaining intact mitochondrial copy number. However, reperfusing a kidney after 45 min of ischemia with varying reperfusion times exacerbates mitochondrial dysfunction and significantly decreases mitochondrial copy number. These declines are particularly evident at 24 h of reperfusion, with some parameters improving by 7 days of reperfusion. Despite these improvements, 7 days of reperfusion did not correlate with renal injury indicators (CrCl- 0.46 ± 0.01, BUN-86.29 ± 4.9, Cr-1.75 ± 0.16) following 45 min of ischemia. Conversely, 15 min of ischemia followed by 7 days of reperfusion restored mitochondrial quality and renal function (CrCl- 7.33 ± 0.59, BUN-43.6 ± 3.16, Cr-0.93 ± 0.14).

Conclusion

The above findings emphasize that mitochondrial quality control alters with the extent of ischemia and subsequent reperfusion time, impacting not only mitochondrial copy number but also the resilience of mitochondria during tissue repair.

Empagliflozin promotes skin flap survival by activating AMPK signaling pathway

Flaps are widely used in surgical wound repair, yet distal necrosis poses a significant postoperative challenge, stemming from potential factors such as inadequate blood perfusion, inflammation, ischemia/reperfusion (I/R) injury, mitochondrial impairment, and subsequent ferroptosis. Empagliflozin (EMPA), a sodium-glucose cotransporter 2 inhibitor, has pharmacological activities that promote angiogenesis, mitophagy, and inhibit inflammation, I/R injury, and ferroptosis. However, it is unclear whether EMPA can enhance flap survival. Here, we established a modified McFarlane flap model and applied EMPA to demonstrate its mechanism of action. 24 rats were evenly divided into four groups: the control, low-dose EMPA (10 mg/kg), high-dose EMPA (30 mg/kg), and inhibitor groups. Molecular biology experiments demonstrated that EMPA promoted the expression of angiogenesis-related factors vascular endothelial growth factor (VEGF) and CD34. Additionally, it also increased superoxide dismutase (SOD) activity and reduced malondialdehyde (MDA) levels, thus suppressing oxidative stress. EMPA further alleviated inflammation by downregulating the expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). In vitro experiments showed that EMPA promoted the proliferation of human umbilical vein endothelial cells (HUVECs) and reduce their reactive oxygen species (ROS) production. Further investigation demonstrated that EMPA improves flap prognosis by inducing the expression of the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway, further promoting mitophagy and inhibiting ferroptosis. These effects collectively contributed to the survival of the skin flap. Overall, our research elucidates the protective effects of EMPA on flap survival and its specific mechanisms, offering new insights into solving post-transplant flap necrosis.

Mechanistic insights into gut microbe derived siderophores and PHD2 interactions with implications for HIF-1α stabilization

In oxygen-deprived conditions, cells respond by activating adaptive mechanisms to bolster their survival and protect tissue integrity. A key player in this process is the HIF-1α signaling cascade, meticulously regulated by Prolyl Hydroxylase Domain 2 (PHD2), which orchestrates cellular responses to varying oxygen levels. The primary aim of this investigation is to utilize gut siderophores as inhibitors of PHD2 in ischemic conditions. This study also helps in understanding the structural mechanisms by which gut microbiota regulate HIF-1α via PHD2 inhibition through the secretion of siderophores. We explore potential PHD2 inhibitors through in-silico approaches, specifically molecular docking, binding pose metadynamics, molecular dynamics simulations, and free energy calculations. We evaluated siderophores secreted by gut microbiota as candidate inhibitors for PHD2. Docking studies revealed that Salmochelin SX exhibits the highest binding affinity to PHD2 (- 9.527 kcal/mol), interacting with key residues such as ASP254, TYR310, ASP315, and ARG322. Despite its high affinity, binding pose metadynamics indicated instability for Salmochelin SX, whereas Staphyloferrin A demonstrated superior stability. Molecular dynamics simulations confirmed stable ligand interactions with PHD2, highlighting HIS313 and ASP315 as critical for inhibition. Principal Component Analysis (PCA) and Free Energy Landscape (FEL) analyses underscored conformational changes and binding stability, suggesting that these interactions may stabilize PHD2's active site and have potential therapeutic implications. Additionally, the study reveals how gut microbiota prevent gut dysbiosis through the stabilization of HIF-1α signaling by secreting siderophores.

Neuroprotective effects of quercetin on hippocampal CA1 neurons following middle cerebral artery ischemia‒reperfusion in male rats: a behavioral, biochemical, and histological study

INTRODUCTION

Cerebral ischemic strokes cause brain damage, primarily through inflammatory factors. One of the regions most affected by middle cerebral artery occlusion (MCAO) is the hippocampus, specifically the CA1 area, which is highly susceptible to ischemia. Previous studies have demonstrated the anti-inflammatory properties of quercetin. Therefore, this study aimed to investigate the neuroprotective effects of quercetin on hippocampal CA1 neurons following MCAO.

MATERIALS AND METHODS

Fifty-six male Albino Wistar rats were divided into seven groups (intact, sham, stroke, vehicle, and three quercetin-treated groups receiving 5, 10, and 20 mg/kg, respectively), each containing 8 rats. Various assessments, including brain water content, the rotarod test, the Bederson neurological score, the Morris water maze (MWM) test, the shuttle box test, histopathological evaluations, and measurements of interleukin-10 (IL-10) and interleukin-1β (IL-1β) levels, were conducted across the groups.

RESULTS

Compared with control rats, 5 and 10 mg/kg quercetin-treated rats presented significant improvements in brain water content, neurological function, and motor function and improved performance in the MWM and shuttle box tests. Histopathological analyses revealed better preservation of CA1 neurons in these groups. Additionally, IL-10 levels significantly increased, whereas IL-1β levels significantly decreased. However, the group receiving 20 mg/kg quercetin showed no statistically significant changes in the parameters assessed (P > 0.05).

CONCLUSION

Quercetin may help prevent or ameliorate brain injuries caused by acute stroke, suggesting its neuroprotective effects. The reduction in IL-1β and increase in IL-10 may play key roles in quercetin's protective mechanism.