Acute Ischemia-reperfusion Injury Research Articles

Cardiac-targeted delivery of a novel Drp1 inhibitor for acute cardioprotection

Dynamin-related protein 1 (Drp1) is a mitochondrial fission protein and a viable target for cardioprotection against myocardial ischaemia-reperfusion injury. Here, we reported a novel Drp1 inhibitor (DRP1i1), delivered using a cardiac-targeted nanoparticle drug delivery system, as a more effective approach for achieving acute cardioprotection. DRP1i1 was encapsulated in cubosome nanoparticles with conjugated cardiac-homing peptides (NanoDRP1i1) and the encapsulation efficiency was 99.3 ± 0.1 %. In vivo, following acute myocardial ischaemia-reperfusion injury in mice, NanoDRP1i1 significantly reduced infarct size and serine-616 phosphorylation of Drp1, and restored cardiomyocyte mitochondrial size to that of sham group. Imaging by mass spectrometry revealed higher accumulation of DRP1i1 in the heart tissue when delivered as NanoDRP1i1. In human cardiac organoids subjected to simulated ischaemia-reperfusion injury, treatment with NanoDRP1i1 at reperfusion significantly reduced cardiac cell death, contractile dysfunction, and mitochondrial superoxide levels. Following NanoDRP1i1 treatment, cardiac organoid proteomics further confirmed reprogramming of contractile dysfunction markers and enrichment of the mitochondrial protein network, cytoskeletal and metabolic regulation networks when compared to the simulated injury group. These proteins included known cardioprotective regulators identified in human organoids and in vivo murine studies following ischaemia-reperfusion injury. DRP1i1 is a promising tool compound to study Drp1-mediated mitochondrial fission and exhibits promising therapeutic potential for acute cardioprotection, especially when delivered using the cardiac-targeted cubosome nanoparticles.

Inflammatory bowel disease increases the severity of myocardial infarction after acute ischemia-reperfusion injury in mice

Inflammatory bowel disease increases the severity of myocardial infarction after acute ischemia-reperfusion injury in mice

BTLA deficiency promotes HSC activation and protects against hepatic ischemia-reperfusion injury.

Hepatic ischemia-reperfusion injury (IRI) is unavoidable even despite the development of more effective surgical approaches. During hepatic IRI, activated HSC (aHSC) are involved in liver injury and recovery. A proportion of aHSC increased significantly both in the mouse liver tissues with IRI and in the primary mouse HSCs and LX-2 cells during hypoxia-reoxygenation. "Loss-of-function" experiments revealed that depleting aHSC with gliotoxin exacerbated liver damage in IRI mice. Subsequently, we found that the transcription of mRNA and the expression of B and T lymphocyte attenuator (BTLA) protein were lower in aHSC compared with quiescent HSCs. Interestingly, overexpression or knockdown of BTLA resulted in opposite changes in the activation of specific markers for HSCs such as collagen type I alpha 1, α-smooth muscle actin, and Vimentin. Moreover, the upregulation of these markers was also observed in the liver tissues of global BLTA-deficient (BTLA-/-) mice and was higher after hepatic IRI. Compared with wild-type mice, aHSC were higher, and liver injury was lower in BTLA-/- mice following IRI. However, the depletion of aHSC reversed these effects. In addition, the depletion of aHSC significantly exacerbated liver damage in BTLA-/- mice with hepatic IRI. Furthermore, the TGF-β1 signaling pathway was identified as a potential mechanism for BTLA to negatively regulate the activation of HSCs in vivo and in vitro. These novel findings revealed a critical role of BTLA. Particularly, the receptor inhibits HSC-activated signaling in acute IRI, implying that it is a potential immunotherapeutic target for decreasing the IRI risk.

#2385 Inhibition of histone lysine demethylases 5 attenuates acute kidney injury but not acute kidney disease or chronic kidney disease

Abstract Background and Aims The histone lysine demethylases 5 (KDM5) are members of the family of Jumonji C domain-containing histone demethylases and catalyze the removal of di- and tri-methyl moieties from the fourth lysine of histone 3 (H3K4me2/3). It has been reported that the KDM5 family mediates a range of physiological and pathological events including cell differentiation, motility, senescence and epithelial-mesenchymal transition (EMT) via activating or repressing transcription in demethylase-dependent or independent manners in both homeostasis and disease. This study investigated the potential role of KDM5 in the development and progression of renal fibrosis in acute kidney injury (AKI), chronic kidney disease (CKD) or AKI to CKD transition (acute kidney disease, AKD). Method We evaluated therapeutic effects of KDM5 inhibition in AKI model of unilateral nephrectomy plus contralateral ischemia-reperfusion (IR) injury, AKI to CKD transition model of unilateral IR injury plus removal of contralateral uninjured kidney after 8 days of IR injury, and CKD model of unilateral ureteral obstruction (UUO) in mice. Results KDM5 C70 inhibitor prevented the increase of blood urea nitrogen and positive areas of trichrome, Sirius red, F4/80 and α-smooth muscle actin in injured kidneys 7 days after IR injury. Significant reductions in renal mRNA levels of pro-inflammatory cytokine/chemokine, EMT and pro-fibrotic markers (IL-1β, IL-6, TNF-α, CCL2, CCL3, GM-CSF, MMP9, fibronectin, vimentin, TGF-β1, COL4A1) were also observed with attenuated mRNA levels of KDM5a-c. In addition, renal protein levels of antioxidants such as catalase, SOD1 and SOD2 were increased in injured kidneys of KDM5 inhibitor-treated mice. However, parameters of renal fibrosis and inflammation were similar between mice without and with KDM5 inhibitor in both AKD and CKD models. Conclusion These data demonstrate that inhibition of KDM5 could prevent renal inflammation and fibrosis after acute and severe IR injury. The activation of KDM5 might be an early step in the development of renal fibrosis after AKI insult.

Increasing HCCS function in vivo mediates restoring heme integrity, limiting superoxide overproduction, and conferring reconditioning mitochondrial function in the acute postischemic heart

Background: A serious consequence of acute myocardial ischemia-reperfusion injury (I/R) is heme impairment which causes mitochondrial dysfunction, which contributes to cell death. Such acute I/R-induced mitochondrial dysfunction is characterized by impaired respiration and overproducing superoxide. The cascading ROS propagates heme damage in the array of mitochondrial electron transport chain, adding insult to myocardial injury. Mitochondrial holocytochrome c synthetase (HCCS) catalyzes attaching heme to apocytochrome c or apocytochrome c1 by forming thioether bonds. We reasoned that overexpression of HCCS would ameliorate I/R injury by stabilization of heme moieties in key mitochondrial enzymes. Methods: A mouse model with overexpression of HCCS in the myocytes (HCCS-tg) was generated and echocardiography was used to evaluate cardiac function. The HCCS-tg mouse was subjected to 30-min of coronary ligation and 24-h of reperfusion. Mitochondria were isolated from the myocardium of the risk region and assessed by OCR. The profile of heme from the cardiac mitochondria was assessed by differential UV/VIS spectral analysis. EPR spin-trapping and ubiquinol (Q2H2)-mediated cytochrome c reduction were used to assay superoxide generation by CxI (complex I) and CxIII (complex III) in mitochondria. Results: We detected gaining HCCS function in vivo (one-fold increase) marginally increases the fractional shortening of the mouse heart. There is no significant difference in heart rate and LVIDs/LVIDd between wild type control and HCCS-tg. Increasing function of HCCS in the myocytes further enhances mitochondrial function of HCCS-tg via increasing state-3 OCR, decreasing state-4 OCR, and alleviating superoxide generation by CxI (NADH-linked) and CxIII (Q2H2-linked). Increased HCCS function significantly decreases the infarct size assessed by IF/AAR and IF/LV when the mouse hearts were subjected to acute I/R injury. Overexpressing HCCS in myocytes further protected the heme integrity and the associated activity of electron transport chain in the mitochondria from acute I/R injury. Acute I/R also mediates downregulation of Cox10 and Cox15 required for mitochondrial a-type heme (heme a) biosynthesis and integrity of Cx4 (complex IV) activity, while increasing HCCS function in vivo preserves the integrity of heme a and protects the levels of Cox10, Cox15, and Cx4 activity after acute I/R injury. Conclusion: Acute I/R mediates mitochondrial heme impairment and associated mitochondrial dysfunction via impairing HCCS function and the thioether bonds of c-type heme, whereas overexpression of HCCS in the myocytes mediates protecting integrity of heme from I/R injury, limiting overproducing superoxide, and conferring reconditioning mitochondrial function in the post-ischemic heart. None. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Multi-Omics Integrated Analysis of the Protective Effect of EZH2 Inhibition in Mice with Renal Ischemia-Reperfusion Injury

Introduction: Acute kidney injury (AKI) is a common clinical syndrome associated with high morbidity and mortality. Inhibition of the methyltransferase enhancer of zeste homolog 2 (EZH2) by its inhibitor 3-deazaneplanocin A (3-DZNeP) exerts renal benefits in acute renal ischemia-reperfusion injury (IRI). However, the underlying mechanisms are not completely known. This study aimed to elucidate the pathological mechanism of EZH2 in renal IRI by combination of multi-omics analysis and expression profiling in a public clinical cohort. Methods: In this study, C57BL/6 J mice were used to establish the AKI model, which were treated with 3-DZNeP for 24 h. Kidney samples were collected for RNA-seq analysis, which was combined with publicly available EZH2 chromatin immunoprecipitation sequencing (ChIP-seq) data of mouse embryonic stem cell for a joint analysis to identify differentially expressed genes. Several selected differentially expressed genes were verified by quantitative PCR. Finally, single-nucleus sequencing data and expression profiling in public clinical datasets were used to confirm the negative correlation of the selected genes with EZH2 expression. Results: 3-DZNeP treatment significantly improved renal pathology and function in IRI mice. Through RNA-seq analysis combined with EZH2 ChIP-seq database, 162 differentially expressed genes were found, which might be involved in EZH2-mediated pathology in IRI kidneys. Four differential expressed genes (Scd1, Cidea, Ghr, and Kl) related to lipid metabolism or cell growth were selected based on Gene Ontology and Kyoto Encyclopedia of Genes and Genome enrichment analysis, which were validated by quantitative PCR. Data from single-nucleus RNA sequencing revealed the negative correlation of these four genes with Ezh2 expression in different subpopulations of proximal tubular cells in IRI mice in a different pattern. Finally, the negative correlation of these four genes with EZH2 expression was confirmed in patients with AKI in two clinical datasets. Conclusions: Our study indicates that Scd1, Cidea, Ghr, and Kl are downstream genes regulated by EZH2 in AKI. Upregulation of EZH2 in AKI inhibits the expression of these four genes in a different population of proximal tubular cells to minimize normal physiological function and promote acute or chronic cell injuries following AKI.

Comprehensive overview of the role of mitochondrial dysfunction in the pathogenesis of acute kidney ischemia-reperfusion injury: a narrative review.

Acute kidney ischemia-reperfusion (IR) injury is a life-threatening condition that predisposes individuals to chronic kidney disease. Since the kidney is one of the most energy-demanding organs in the human body and mitochondria are the powerhouse of cells, mitochondrial dysfunction plays a central role in the pathogenesis of IR-induced acute kidney injury. Mitochondrial dysfunction causes a reduction in adenosine triphosphate production, loss of mitochondrial dynamics (represented by persistent fragmentation), and impaired mitophagy. Furthermore, the pathological accumulation of succinate resulting from fumarate reduction under oxygen deprivation (ischemia) in the reverse flux of the Krebs cycle can eventually lead to a burst of reactive oxygen species driven by reverse electron transfer during the reperfusion phase. Accumulating evidence indicates that improving mitochondrial function, biogenesis, and dynamics, and normalizing metabolic reprogramming within the mitochondria have the potential to preserve kidney function during IR injury and prevent progression to chronic kidney disease. In this review, we summarize recent advances in understanding the detrimental role of metabolic reprogramming and mitochondrial dysfunction in IR injury and explore potential therapeutic strategies for treating kidney IR injury.

Ultrasound molecular imaging for early detection of acute renal ischemia-reperfusion injury.

Microcirculatory perfusion disorder and inflammatory response are critical links in acute kidney injury (AKI). We aim to construct anti-vascular cell adhesion molecule-1(VCAM-1) targeted microbubbles (TM) to monitor renal microcirculatory perfusion and inflammatory response. TM carrying VCAM-1 polypeptide was constructed by biological coupling. The binding ability of TM to human umbilical vein endothelial cells (HUVECs) was detected. Bilateral renal ischemia-reperfusion injury (IRI) models of mice were established to evaluate microcirculatory perfusion and inflammatory response using TM. Thirty-six mice were randomly divided into six groups according to the different reperfusion time (0.5, 2, 6, 12, and 24 h) and sham-operated group (Sham group). The correlation of TM imaging with serum and histopathological biomarkers was investigated. TM has advantages such as uniform distribution, regular shape, high stability, and good biosafety. TM could bind specifically to VCAM-1 molecule expressed by tumor necrosis factor-alpha (TNF-α)-treated HUVECs. In the renal IRI-AKI model, the area under the curve (AUC) of TM significantly decreased both in the renal cortical and medullary after 2 h of reperfusion compared with the Sham group (p < 0.05). Normalized intensity difference (NID) of TM at different reperfusion time was all higher than that of blank microbubbles (BM) and the Sham group (p < 0.05). Ultrasound molecular imaging of TM could detect AKI early before commonly used renal function markers, histopathological biomarkers, and BM imaging. AUC of TM was negatively correlated with serum creatinine (Scr), blood urea nitrogen (BUN), and Cystatin C (Cys-C) levels, and NID of TM was linearly correlated with VCAM-1, TNF-α, and interleukin-6 (IL-6) expression (p < 0.05). Ultrasound molecular imaging based on TM carrying VCAM-1 polypeptide can accurately evaluate the changes in renal microcirculatory perfusion and inflammatory response, which might be a promising modality for early diagnosis of AKI.

A novel dual near-infrared fluorescent probe for bioimaging and visualization of viscosity in acute alcoholic liver injury.

A dual NIR fluorescent probe Cy-ND is developed for viscosity sensing with λex/em = 766/806 nm, making it apt for biological analysis, whose response is validated through DFT and TDDFT computations. Cy-ND successfully detected viscosity changes amidst acute alcohol-induced liver injury and liver ischemia-reperfusion injury.

Cardiac endothelial ischemia/reperfusion injury-derived protein damage-associated molecular patterns disrupt the integrity of the endothelial barrier

Human cardiac microvascular endothelial cells (HCMECs) are sensitive to ischemia and vulnerable to damage during reperfusion. The release of damage-associated molecular patterns (DAMPs) during reperfusion induces additional tissue damage. The current study aimed to identify early protein DAMPs in human cardiac microvascular endothelial cells subjected to ischemia-reperfusion injury (IRI) using a proteomic approach and their effect on endothelial cell injury. HCMECs were subjected to 60 min of simulated ischemia and 6 h of reperfusion, which can cause lethal damage. DAMPs in the culture media were subjected to liquid chromatography-tandem mass spectrometry proteomic analysis. The cells were treated with endothelial IRI-derived DAMP medium for 24 h. Endothelial injury was assessed by measuring lactate dehydrogenase activity, morphological features, and the expression of endothelial cadherin, nitric oxide synthase (eNOS), and caveolin-1. The top two upregulated proteins, DNAJ homolog subfamily B member 11 and pyrroline-5-carboxylate reductase 2, are promising and sensitive predictors of cardiac microvascular endothelial damage. HCMECs expose to endothelial IRI-derived DAMP, the lactate dehydrogenase activity was significantly increased compared with the control group (10.15 ± 1.03 vs 17.67 ± 1.19, respectively). Following treatment with endothelial IRI-derived DAMPs, actin-filament dysregulation, and downregulation of vascular endothelial cadherin, caveolin-1, and eNOS expressions were observed, along with cell death. In conclusion, the early protein DAMPs released during cardiac microvascular endothelial IRI could serve as novel candidate biomarkers for acute myocardial IRI. Distinct features of impaired plasma membrane integrity can help identify therapeutic targets to mitigate the detrimental consequences mediated of endothelial IRI-derived DAMPs.

Left Ventricular Function after Acute Ischemia-Reperfusion Injury in Cardiac Decentralized Dogs Subject to Ischemic Conditioning

Left Ventricular Function after Acute Ischemia-Reperfusion Injury in Cardiac Decentralized Dogs Subject to Ischemic Conditioning

Analysis of hippocampus in rats with acute brain ischemia-reperfusion injury treated with leuprolide acetate, an agonist of GnRH.

The hippocampus is highly vulnerable to damage in the brain ischemia-reperfusion injury model. Leuprolide acetate has been shown to promote neurological recovery after injury in various regions of the central nervous system. The objective of this study was to assess the histology of the hippocampus and the expression of neuronal recovery markers, specifically the 200 kDa neurofilaments and the myelin basic protein, in rats with brain ischemia-reperfusion injury treated with leuprolide acetate. The rats were divided into three groups: Sham, ischemia-reperfusion with saline solution, and ischemia-reperfusion treated with leuprolide acetate. Coronal brain slices were obtained and stained with hematoxylin-eosin. The histological analysis involved quantifying the number of neurons in the hippocampal regions CA1, CA3 and DG. The myelin basic protein and neurofilaments were quantified using western blot. The number of neurons in CA1 and DG was significantly higher in the leuprolide acetate group compared to the untreated group. Additionally, the expression of neurofilament and myelin basic protein markers was significantly increased in rats treated with leuprolide acetate compared to the untreated rats. Leuprolide acetate promotes the recovery of hippocampal neurons in an acute brain ischemia-reperfusion injury model. These findings suggest that leuprolide acetate could be a potential therapeutic intervention for reversing damage in hippocampal ischemic lesions.

Targeting Toll-like receptor 4 and the NLRP3 inflammasome: Novel and emerging therapeutic targets for hyperuricaemia nephropathy.

The clinical manifestation of hyperuricaemia, known as hyperuricaemia nephropathy, is relatively common. Its pathophysiology is largely based on chronic inflammation in circulatory and renal tissues. Toll-like receptor 4 (TLR4), a subclass of innate immune receptors, detects both pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs), initiating inflammatory and immune responses that lead to the release of pro-inflammatory cytokines interleukin (IL) 1β and tumor necrosis factor alpha (TNF-α). These cytokines are pivotal in renal inflammation, especially in conditions like hyperuricaemia, acute renal injury, ischemia-reperfusion injury, and acute renal failure. The nucleotide-binding oligomerization domain (NOD)-like receptor pyrin domain-containing 3 (NLRP3) inflammasome, an essential component of the innate immune signaling complex, plays a central role in inflammation. It finely regulates the activation of caspase-1 and the production and secretion of the pro-inflammatory cytokine IL-1β, mediating and amplifying the inflammatory cascade response. Activation of TLR4 indirectly promotes the assembly of the NLRP3 inflammasome by regulating the nuclear factor kappa B (NF-κB) signaling pathway, thereby amplifying the inflammatory process and playing a significant pro-inflammatory role in hyperuricaemia nephropathy. TLR4 and NLRP3 inflammasome are anticipated to be novel markers and therapeutic targets for assessing treatment efficacy and prognosis in hyperuricaemia nephropathy. This paper provides a comprehensive overview of the structural composition and biological functions of TLR4 and NLRP3 inflammasome and systematically reviews their relevance in the pathogenesis of hyperuricaemia nephropathy.

Targeting mitochondrial shape: at the heart of cardioprotection

There remains an unmet need to identify novel therapeutic strategies capable of protecting the myocardium against the detrimental effects of acute ischemia–reperfusion injury (IRI), to reduce myocardial infarct (MI) size and prevent the onset of heart failure (HF) following acute myocardial infarction (AMI). In this regard, perturbations in mitochondrial morphology with an imbalance in mitochondrial fusion and fission can disrupt mitochondrial metabolism, calcium homeostasis, and reactive oxygen species production, factors which are all known to be critical determinants of cardiomyocyte death following acute myocardial IRI. As such, therapeutic approaches directed at preserving the morphology and functionality of mitochondria may provide an important strategy for cardioprotection. In this article, we provide an overview of the alterations in mitochondrial morphology which occur in response to acute myocardial IRI, and highlight the emerging therapeutic strategies for targeting mitochondrial shape to preserve mitochondrial function which have the future therapeutic potential to improve health outcomes in patients presenting with AMI.

Malonate protection against acute infarction in isolated mouse hearts is lost in the presence of insulin

Abstract Background &amp; Objectives Malonate, an inhibitor of mitochondrial succinate dehydrogenase (SDH), is a promising novel protectant against acute ischaemia-reperfusion injury (IRI) through reduction of ischaemic succinate accumulation and ROS production during early reperfusion. Malonate is still protective when given only at reperfusion, making it an ideal agent for treating AMI patients. However, numerous studies demonstrated that the metabolic milieu could affect the potency of cardioprotective treatments. Therefore, in this study, we explored whether and how the severity of cardiac I/R injury and cardioprotection by malonate is affected by the metabolic milieu. We hypothesized that protection by malonate is affected by metabolic milie. Methods Isolated Langendorff-perfused hearts (n=8 to 19 per group) of C57Bl/6N mice were perfused with perfusate to which substrates and hormones were added in a step-wise manner: 1) glucose (G), 2) glucose + glutamine (GG), 3) glucose + glutamine + palmitate (GGP), or 4) glucose + glutamine + palmitate + insulin (GGPI), and subjected to 30 min ischaemia (I) and 90 min reperfusion (R). Heart were treated with malonate (5mM) or vehicle (saline) during the first 5 min of reperfusion only. Cardiac function of the left ventricle was monitored by a balloon in the left ventricle. Coronary effluent was collected at 7 time points of reperfusion to detect the activity of lactate dehydrogenase (LDH) as an indicator of cell death. At the end reperfusion, hearts were used for infarct size determination through TTC staining. Data are presented as mean ± SD. Results Going from glucose-only perfusate to a perfusate containing all examined substrates and hormones, the severity of cardiac I/R injury increased: infarct size (%) went from 31.9 ± 10.9% to 37.7 ± 10.6% to 52.3 ± 14.2%, and finally to 68 ± 9.9 %. Similar trends for increased IRI were observed for LDH, End-Diastolic Pressure (EDP) and recovery of the Rate-Pressure Product (RPP). When compared with vehicle control, malonate significantly decreased IS% (control vs malonate: 31.9 ± 10.9% vs. 23.3 ± 4.8%, 37.7 ± 10.6% vs. 20.9 ± 8.5%, 68 ± 9.9% vs. 40.2 ± 9.2 %), and increased the RRP recovery (64.1 ± 16.6 %vs. 83.3 ± 17.9 %, 55.6 ± 11% vs. 72.3 ± 4%, 39.3 ± 15.6% vs. 55.9 ± 8.3%) in the G, GG and GGP group. The EDP was significantly decreased by malonate in the G and GG group (32.8 ± 14.3 mmHg vs. 20.9 ± 9.8 mmHg, 35.1 ± 8.7 mmHg vs. 22.2 ± 8.6 mmHg ). LDH was only significantly decreased by malonate in the GG group (35.2 ± 12.9 vs. 17.1 ± 7.7 U / GWW). Most importantly, adding insulin to the perfusate nullified protection by malonate for all four outcomes. Conclusions The severity of cardiac I/R injury is lowest with glucose-only perfusate, and increased with increased complexity of the metabolic milieu. Although malonate is a strong protectant against cardiac IRI for most metabolic milieus, in the isolated heart, protection is lost in the presence of insulin.

Abstract 14250: ND-13, a Small DJ-1 Derived Peptide, Confers Cardioprotection by Targeting Mitochondrial Homeostasis

Objectives: DJ-1 protein is a multifunctional protein with cardioprotective effects against acute myocardial ischemia-reperfusion injury (IRI). This study aims to elucidate whether ND-13, a small peptide derived from DJ-1, can confer acute cardioprotection after IRI by preserving mitochondrial homeostasis through improvements in mitochondrial respiratory capacity and regulating the balance between mitochondrial fusion/fission. By enhancing mitochondrial respiration and maintaining the integrity of the mitochondrial network, ND-13 may provide a novel therapeutic strategy for cardioprotection in cardiomyocytes following IRI. Methods: In vitro , ex vivo and in vivo murine models of IRI were used to elucidate the cardioprotective effects of ND-13. Infarct size, cardiac function and mitochondrial function were assessed. Results: ND-13 was shown to confer cardioprotection in three distinct models of IRI: (i) in vitro , cardiomyocyte (CM) death was reduced by 42% (64±1% untreated vs 37±2% treated; p≤0.01); (ii) ex vivo Langendorrf, with 43% decrease in infarct size (51±6.4% untreated vs 29±8.8% treated; p≤0.05); (iii) in vivo , with 35% reduction in infarct size (49±6.4% untreated vs 32±5.0% treated; p≤0.0001). CMs treated with ND-13 in the in vitro model of IRI demonstrated a significant increase in mitochondrial respiration rates, (basal: untreated 37±3 vs treated 63±10 pmol/min/cells, p≤0.05; maximal: untreated 286±20 vs treated 494±53 pmol/min/cells, p≤0.001; and spare respiratory capacity: untreated 251±18 vs treated 421±43 pmol/min/cells, p≤0.001) and a significant increase in levels of cytosolic ATP (untreated 4.0 ± 0.3 vs treated 5.6 ± 0.5 μM, p≤0.05). Conclusion: We demonstrate for the first time, cardioprotection with the DJ-1-derived peptide, ND-13, and this beneficial effect appears to be mediated by its mitoprotective actions with enhanced mitochondrial respiratory efficiency and increased ATP production. Upcoming research aims to explore if ND-13 promotes oxidative phosphorylation by directly binding to complexes of the electron transport chain to maximize respiratory function or by enhancing pyruvate dehydrogenase activity, thereby potentially influencing the regulation of the fission/fusion process.

The effect of Edaravone on lung injury after lower limb ischemiareperfusion in a rat model: Biochemical and histopathological insights

Aim: Lower limb ischemia/reperfusion leads to distant organ dysfunction, notably affecting the lungs, resulting in respiratory failure and significant morbidity and mortality. Edaravone is a new free radical scavenger and has attracted the attention of researchers. This study aims to examine edaravone's influence on lung injury arising from lower limb ischemia-reperfusion. Material and Methods: Forty male Wistar rats were categorized into groups: Sham, Ischemia/Reperfusion (IR), Solvent, and Edaravone. The infrarenal abdominal aorta was clamped for 120 minutes and then reperfused for another 120 minutes. Edaravone was administered 30 minutes before the ischemic event. Then we analyzed serum and lung tissue samples for malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), and nitric oxide (NO) levels. Furthermore, a thorough histopathological assessment was conducted. Results: In the IR group, edaravone notably reduced serum and lung MDA levels. While significant differences in serum SOD and NO levels existed between the IR and edaravone groups, similar differences were not found in the lung tissue samples. There appeared to be no significant impact of edaravone on serum and lung GPx levels. The histopathological investigation revealed that the lung injury score was significantly higher in the IR group compared to the control group, a difference mitigated by edaravone treatment. Conclusion: Our findings suggest that edaravone mitigates lower limb ischemia-reperfusion-induced lung injury, both biochemically and histopathologically. Our findings imply the potential utility of this agent in the context of acute ischemia-reperfusion injury following vascular surgery.

Inflammatory Bowel Disease Increases the Severity of Myocardial Infarction after Acute Ischemia-Reperfusion Injury in Mice.

(1) Background: Increased risk of myocardial infarction (MI) has been linked to several inflammatory conditions, including inflammatory bowel disease (IBD). However, the relationship between IBD and MI remains unclear. Here, we implemented an original mouse model combining IBD and MI to determine IBD's impact on MI severity and the link between the two diseases. (2) Methods: An IBD model was established by dextran sulfate sodium (DSS) administration in drinking water, alone or with oral C. albicans (Ca) gavage. IBD severity was assessed by clinical/histological scores and intestinal/systemic inflammatory biomarker measurement. Mice were subjected to myocardial ischemia-reperfusion (IR), and MI severity was assessed by quantifying infarct size (IS) and serum cardiac troponin I (cTnI) levels. (3) Results: IBD mice exhibited elevated fecal lipocalin 2 (Lcn2) and IL-6 levels. DSS mice exhibited almost two-fold increase in IS compared to controls, with serum cTnI levels strongly correlated with IS. Ca inoculation tended to worsen DSS-induced systemic inflammation and IR injury, an observation which is not statistically significant. (4) Conclusions: This is the first proof-of-concept study demonstrating the impact of IBD on MI severity and suggesting mechanistic aspects involved in the IBD-MI connection. Our findings could pave the way for MI therapeutic approaches based on identified IBD-induced inflammatory mediators.

Huoxin Pill Reduces Myocardial Ischemia Reperfusion Injury in Rats via TLR4/NFκB/NLRP3 Signaling Pathway.

To explore the protective effect of Huoxin Pill (HXP) on acute myocardial ischemia-reperfusion (MIRI) injury in rats. Seventy-five adult SD rats were divided into the sham-operated group, model group, positive drug group (diltiazem hydrochloride, DH), high dose group (24 mg/kg, HXP-H) and low dose group (12 mg/kg, HXP-L) of Huoxin Pill (n=15 for every group) according to the complete randomization method. After 1 week of intragastric administration, the left anterior descending coronary artery of the rat's heart was ligated for 45 min and reperfused for 3 h. Serum was separated and the levels of creatine kinase (CK), creatine kinase isoenzyme (CK-MB) and lactate dehydrogenase (LDH), superoxide dismutase (SOD), and malondialdehyde (MDA), hypersensitive C-reactive protein (hs-CRP) and interleukin-1β (IL-1β) were measured. Myocardial ischemia rate, myocardial infarction rate and myocardial no-reflow rate were determined by staining with Evans blue and 2,3,5-triphenyltetrazolium chloride (TTC). Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and Bioinformatics Analysis Tool for Molecular mechANism of Traditional Chinese Medicine (BATMAN) databases were used to screen for possible active compounds of HXP and their potential therapeutic targets; the results of anti-inflammatory genes associated with MIRI were obtained from GeneCards, Drugbank, Online Mendelian Inheritance in Man (OMIM), and Therapeutic Target Datebase (TTD) databases was performed; Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment were used to analyze the intersected targets; molecular docking was performed using AutoDock Tools. Western blot was used to detect the protein expression of Toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NFκB)/NOD-like receptor protein 3 (NLRP3). Compared with the model group, all doses of HXP significantly reduced the levels of LDH, CK and CK-MB (P<0.05, P<0.01); HXP significantly increased serum activity of SOD (P<0.05, P<0.01); all doses of HXP significantly reduced the levels of hs-CRP and IL-1β (P<0.05, P<0.01) and the myocardial infarction rate and myocardial no-reflow rate (P<0.01). GO enrichment analysis mainly involved positive regulation of gene expression, extracellular space and identical protein binding, KEGG pathway enrichment mainly involved PI3K-Akt signaling pathway and lipid and atherosclerosis. Molecular docking results showed that kaempferol and luteolin had a better affinity with TLR4, NFκB and NLRP3 molecules. The protein expressions of TLR4, NFκB and NLRP3 were reduced in the HXP group (P<0.01). HXP has a significant protective effect on myocardial ischemia-reperfusion injury in rats, and its effect may be related to the inhibition of redox response and reduction of the inflammatory response by inhibiting the TLR4NFκB/NLRP3 signaling pathway.

Differential temporal therapies with pharmacologically targeted mitochondrial fission/fusion protect the brain against acute myocardial ischemia-reperfusion injury in prediabetic rats: The crosstalk between mitochondrial apoptosis and inflammation

An imbalance of brain mitochondrial dynamics, increases in brain inflammation and apoptosis, and increasing cognitive dysfunction, have been reported as being associated with prediabetes and myocardial ischemia-reperfusion (IR) injury. Since inhibiting mitochondrial fission with Mdivi-1 or promoting fusion with M1 had cardioprotective effects in myocardial IR injury and obesity, the neuroprotective roles of Mdivi-1 and M1 when administered at different time points of myocardial IR injury in obese prediabetes have never been determined. Ninety-six male Wistar rats were fed with either a normal (ND: n = 8) or a high-fat diet to induce prediabetes (HFD: n = 88) for 12 weeks. At week 13, all rats were subjected to left anterior descending coronary artery ligation for 30 min, followed by reperfusion for 120 min. HFD rats were randomly divided into 10 groups and assigned into either a pre-ischemic group treated with vehicle (HFV), pre-ischemic, during-ischemic, or onset of reperfusion groups treated with either Mdivi-1 (MDV), M1, or combined (COM). Heart function was examined invasively, with the heart being terminated to investigate myocardial infarction. Brains were collected to determine mitochondrial functions, inflammation, apoptosis, and pathological markers. Mdivi-1, M1, and COM treatment at different periods exerted cardioprotection against myocardial IR injury in HFD-fed rats by reducing infarct size and left ventricular dysfunction. All interventions also improved all brain pathologies against myocardial IR injury in prediabetic rats. These findings suggest that differential temporal modulation of mitochondrial dynamics may be appropriate regimens for preventing heart and brain complications after myocardial IR injury in obese prediabetes.