Acute Ischemia-reperfusion Research Articles

Transcriptional responses in a mouse model of silicone wire embolization induced acute retinal artery ischemia and reperfusion.

Acute retinal ischemia and ischemia-reperfusion injury are the primary causes of retinal neural cell death and vision loss in retinal artery occlusion (RAO). The absence of an accurate mouse model for simulating the retinal ischemic process has hindered progress in developing neuroprotective agents for RAO. We developed a unilateral pterygopalatine ophthalmic artery occlusion (UPOAO) mouse model using silicone wire embolization combined with carotid artery ligation. The survival of retinal ganglion cells and visual function were evaluated to determine the duration of ischemia. Immunofluorescence staining, optical coherence tomography, and haematoxylin and eosin staining were utilized to assess changes in major neural cell classes and retinal structure degeneration at two reperfusion durations. Transcriptomics was employed to investigate alterations in the pathological process of UPOAO following ischemia and reperfusion, highlighting transcriptomic differences between UPOAO and other retinal ischemia-reperfusion models. The UPOAO model successfully replicated the acute interruption of retinal blood supply observed in RAO. 60 min of Ischemia led to significant loss of major retinal neural cells and visual function impairment. Notable thinning of the inner retinal layer, especially the ganglion cell layer, was evident post-UPOAO. Temporal transcriptome analysis revealed various pathophysiological processes related to immune cell migration, oxidative stress, and immune inflammation during the non-reperfusion and reperfusion periods. A pronounced increase in microglia within the retina and peripheral leukocytes accessing the retina was observed during reperfusion periods. Comparison of differentially expressed genes (DEGs) between the UPOAO and high intraocular pressure models revealed specific enrichments in lipid and steroid metabolism-related genes in the UPOAO model. The UPOAO model emerges as a novel tool for screening pathogenic genes and promoting further therapeutic research in RAO.

Transcriptional responses in a mouse model of silicone wire embolization induced acute retinal artery ischemia and reperfusion

Acute retinal ischemia and ischemia-reperfusion injury are the primary causes of retinal neural cell death and vision loss in retinal artery occlusion (RAO). The absence of an accurate mouse model for simulating the retinal ischemic process has hindered progress in developing neuroprotective agents for RAO. We developed a unilateral pterygopalatine ophthalmic artery occlusion (UPOAO) mouse model using silicone wire embolization combined with carotid artery ligation. The survival of retinal ganglion cells and visual function were evaluated to determine the duration of ischemia. Immunofluorescence staining, optical coherence tomography, and haematoxylin and eosin staining were utilized to assess changes in major neural cell classes and retinal structure degeneration at two reperfusion durations. Transcriptomics was employed to investigate alterations in the pathological process of UPOAO following ischemia and reperfusion, highlighting transcriptomic differences between UPOAO and other retinal ischemia-reperfusion models. The UPOAO model successfully replicated the acute interruption of retinal blood supply observed in RAO. 60 min of Ischemia led to significant loss of major retinal neural cells and visual function impairment. Notable thinning of the inner retinal layer, especially the ganglion cell layer, was evident post-UPOAO. Temporal transcriptome analysis revealed various pathophysiological processes related to immune cell migration, oxidative stress, and immune inflammation during the non-reperfusion and reperfusion periods. A pronounced increase in microglia within the retina and peripheral leukocytes accessing the retina was observed during reperfusion periods. Comparison of differentially expressed genes (DEGs) between the UPOAO and high intraocular pressure models revealed specific enrichments in lipid and steroid metabolism-related genes in the UPOAO model. The UPOAO model emerges as a novel tool for screening pathogenic genes and promoting further therapeutic research in RAO.

Dietary Fiber-Derived Microbial Metabolites Prevent Acute and Chronic Kidney Ischemia-Reperfusion Injury (IRI) through G Protein-Coupled Receptor GPR43

Dietary Fiber-Derived Microbial Metabolites Prevent Acute and Chronic Kidney Ischemia-Reperfusion Injury (IRI) through G Protein-Coupled Receptor GPR43

Therapeutic potential of mesenchymal stromal cells on morphological parameters in the hippocampus of rats with brain ischemia-reperfusion modeling

Ischemic stroke is an extremely important pathology with high mortality, in which more than 50 % of patients with occlusion of the main vessels remain disabled, despite early reperfusion therapy by thrombolysis or thrombectomy. As part of the regenerative strategy, stem cell transplantation in ischemic stroke became a new impetus. Cell therapy with the use of mesenchymal stromal cells demonstrated encouraging results regarding endogenous mechanisms of neuroregeneration in response to ischemic damage to brain structures. The aim of the research is to study the influence of mesenchymal stromal cells of various genesis, lysate of mesenchymal stromal cells obtained from Wharton’s jelly umbilical cord and citicoline on the dynamics of morphological changes in the hippocampal CA1 region of rats with acute cerebral ischemia-reperfusion according to light microscopy and micromorphometry data. The experiment was carried out using 200 male Wistar rats, which were subjected to ischemia-reperfusion by reversible 20-minute bilateral occlusion of the internal carotid arteries. Animals with modeled pathology were intravenously transplanted with mesenchymal stromal cells of various genesis (from Wharton’s jelly of the human umbilical cord, human and rat adipose tissue), and rat embryonic fibroblasts, lysate of mesenchymal stromal cells and citicoline were injected. Histological analysis of rat brain sections was performed on the 7th and 14th day of the experiment. Statistical analysis was performed using “Statistica 6.0” (StatSoft® Snc, USA). The significance of differences was assessed using the Student’s t-test and the nonparametric Mann-Whitney U test. During the study, it was found that modeled ischemia-reperfusion in rats caused almost complete degeneration of the structure of the pyramidal layer of hippocampal CA1 region, gave uniformity to the structure of the radiant layer, infiltration of microglia, contributed to the disruption of the arrangement of apical dendrite bundles and narrowing of blood vessels as a result of perivascular edema. Also, the modeled pathology reduced the total number of neuronal nuclei in the hippocampal CA1 area, the overwhelming majority of which had signs of pathological changes. Transplantation of mesenchymal stromal cells of various origins, lysate of mesenchymal stromal cells and citicoline contributed to a significant increase in the number of neuronal nuclei in the hippocampal CA1 zone and nuclei that did not undergo pathological changes. The most positive effect was found in the transplantation of mesenchymal stromal cells from human Wharton’s jelly-derived cells. Thus, both in the subacute and recovery periods of ischemic stroke in rats, the transplantation of human Wharton’s jelly-derived mesenchymal stromal cells was significantly surpassed the reference drug citicoline in its ability to reduce the number of pathologically changed nuclei by 1.5 times (p<0.05). At the same time, the number of pathologically unchanged nuclei significantly exceeded the number of nuclei with signs of karyorrhexis and karyopyknosis, so it would be advisable to use mesenchymal stromal cells of various genesis, lysate or citicoline in conditions of acute cerebral ischemia-reperfusion, taking into account their ability to reduce the volume of the infarct. In the future, an injectable drug will be created from the most effective culture of mesenchymal stromal cells in terms of cerebroprotective properties for cell therapy of patients with acute ischemic stroke.

Comparison of Different Animal Models in Hindlimb Functional Recovery after Acute Limb Ischemia-Reperfusion Injury.

Acute limb ischemia (ALI) is a sudden lack of blood flow to a limb, primarily caused by arterial embolism and thrombosis. Various experimental animal models, including non-invasive and invasive methods, have been developed and successfully used to induce limb ischemia-reperfusion injuries (L-IRI). However, there is no consensus on the methodologies used in animal models for L-IRI, particularly regarding the assessment of functional recovery. The present study aims to compare different approaches that induce L-IRI and determine the optimal animal model to study functional limb recovery. In this study, we applied a pneumatic cuff as a non-invasive method and ligated the aorta, iliac, or femoral artery as invasive methods to induce L-IRI. We have measured grip strength, motor function, creatine kinase level, inflammatory markers such as nuclear factor NF-κB, interleukin-6 (IL-6), hypoxia markers such as hypoxia-induced factor-1α (HIF-1α), and evaluated the muscle injury with hematoxylin and eosin (H&E) staining in Sprague Dawley rats after inducing L-IRI. The pneumatic pressure cuff method significantly decreased the muscle strength of the rats, causing the loss of ability to hold the grid and inducing significant limb function impairment, while artery ligations did not. We conclude from this study that the tourniquet cuff method could be ideal for studying functional recovery after L-IRI in the rat model.

Long-term major events after hospital discharge for out-of-hospital cardiac arrest

BackgroundCardiac arrest remains a global health issue with limited data on long-term outcomes, particularly regarding recurrent cardiovascular events in patients surviving out-of-hospital cardiac arrest. (OHCA). We aimed to describe the long-term occurrence of major cardiac event defined by hospital admission for cardiovascular events or death in OHCA hospital survivors, whichever came first. Our secondary objective were to assess separately occurrence of hospital admission and death, and to identify the factors associated with major event occurrence. We hypothesized that patients surviving an OHCA has a protracted increased risk of cardiovascular events, due to both presence of the baseline conditions that lead to OHCA, and to the cardiovascular consequences of OHCA induced acute ischemia-reperfusion.MethodsConsecutive OHCA patients from three hospitals of Sudden Death Expertise Center (SDEC) Registry, discharged alive from 2011 to 2015 were included. Long-term follow-up data were obtained using national inter-regime health insurance information system (SNIIRAM) database and the national French death registry. The primary endpoint was occurrence of a major event defined by hospital admission for cardiovascular events and death, whichever came first during the follow-up. The starting point of the time-to-event analysis was the date of hospital discharge. The follow-up was censored on the date of the first event. For patients without event, follow-up was censored on the date of December, 29th, 2016.ResultsA total of 306 patients (mean age 57; 77% male) were analyzed and followed over a median follow-up of 3 years for hospital admission for cardiovascular event and 6 years for survival. During this period, 38% patients presented a major event. Hospital admission for cardiovascular events mostly occurred during the first year after the OHCA whereas death occurred more linearly during the all period. A previous history of chronic heart failure and coronary artery disease were independently associated with the occurrence of major event (HR 1.75, 95%CI[1.06-2.88] and HR 1.70, 95%CI[1.11-2.61], respectively), whereas post-resuscitation myocardial dysfunction, cardiogenic shock and cardiologic cause of cardiac arrest did not.ConclusionSurvivors from OHCA must to be considered at high risk of cardiovascular event occurrence whatever the etiology, mainly during the first year following the cardiac arrest and should require closed monitoring.

Irisin-Encapsulated Mitochondria-Targeted Biomimetic Nanotherapeutics for Alleviating Acute Kidney Injury.

Acute kidney injury (AKI) is the sudden decrease in renal function that can be attributed to dysregulated reactive oxygen species (ROS) production and impaired mitochondrial function. Irisin, a type I membrane protein secreted by skeletal muscles in response to physical activity, has been reported to alleviate kidney damage through regulation of mitochondrial biogenesis and oxidative metabolism. In this study, a macrophage membrane-coated metal-organic framework (MCM@MOF) is developed as a nanocarrier for encapsulating irisin to overcome the inherent characteristics of irisin, including a short circulation time, limited kidney-targeting ability, and low membrane permeability. The engineered irisin-mediated biomimetic nanotherapeutics have extended circulation time and enhanced targeting capability toward injured kidneys due to the preservation of macrophage membrane proteins. The irisin-encapsulated biomimetic nanotherapeutics effectively mitigate acute ischemia-reperfusion injury by protecting mitochondrial function and modulating SOD2 levels in renal tubular epithelial cells. The present study provides novel insights to advance the development of irisin as a potential therapeutic approach for AKI.

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

#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.

Role of the cGAS DNA sensing pathway in acute intestinal ischemia-reperfusion injury

Role of the cGAS DNA sensing pathway in acute intestinal ischemia-reperfusion injury

Parental obesity predisposes offspring to kidney dysfunction and increased susceptibility to ischemia-reperfusion injury in a sex-dependent manner.

Although obesity is recognized as a risk factor for cardiorenal and metabolic diseases, the impact of parental obesity on the susceptibility of their offspring to renal injury at adulthood is unknown. We examined the impact of parental obesity on offspring kidney function, morphology, and markers of kidney damage after acute kidney injury (AKI). Offspring from normal (N) diet-fed C57BL/6J parents were fed either N (NN) or a high-fat (H) diet (NH) from weaning until adulthood. Offspring from obese H diet-fed parents were fed N (HN) or H diet (HH) after weaning. All offspring groups were submitted to bilateral AKI by clamping the left and right renal pedicles for 30 min. Compared with male NH and NN offspring from lean parents, male HH and HN offspring from obese parents exhibited higher kidney injury markers such as urinary, renal osteopontin, plasma creatinine, urinary albumin excretion, and neutrophil gelatinase-associated lipocalin (NGAL) levels, and worse histological injury score at 22 wk of age. Only albumin excretion and NGAL were elevated in female HH offspring from obese parents compared with lean and obese offspring from lean parents. We also found an increased mortality rate and worse kidney injury scores after AKI in male offspring from obese parents, regardless of the diet consumed after weaning. Female offspring were protected from major kidney injury after AKI. These results indicate that parental obesity leads to increased kidney injury in their offspring after ischemia-reperfusion in a sex-dependent manner, even when their offspring remain lean.NEW & NOTEWORTHY Offspring from obese parents are more susceptible to kidney injury and worse outcomes following an acute ischemia-reperfusion insult. Male, but not female, offspring from obese parents exhibit increased blood pressure early in life. Female offspring are partially protected against major kidney injury induced by ischemia-reperfusion.

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.

Macrophages promote the transition from myocardial ischemia reperfusion injury to cardiac fibrosis in mice through GMCSF/CCL2/CCR2 and phenotype switching.

Following acute myocardial ischemia reperfusion (MIR), macrophages infiltrate damaged cardiac tissue and alter their polarization phenotype to respond to acute inflammation and chronic fibrotic remodeling. In this study we investigated the role of macrophages in post-ischemic myocardial fibrosis and explored therapeutic targets for myocardial fibrosis. Male mice were subjected to ligation of the left coronary artery for 30 min. We first detected the levels of chemokines in heart tissue that recruited immune cells infiltrating into the heart, and found that granulocyte-macrophage colony-stimulating factor (GMCSF) released by mouse cardiac microvascular endothelial cells (MCMECs) peaked at 6 h after reperfusion, and c-c motif chemokine ligand 2 (CCL2) released by GMCSF-induced macrophages peaked at 24 h after reperfusion. In co-culture of BMDMs with MCMECs, we demonstrated that GMCSF derived from MCMECs stimulated the release of CCL2 by BMDMs and effectively promoted the migration of BMDMs. We also confirmed that GMCSF promoted M1 polarization of macrophages in vitro, while GMCSF neutralizing antibodies (NTABs) blocked CCL2/CCR2 signaling. In MIR mouse heart, we showed that GMCSF activated CCL2/CCR2 signaling to promote NLRP3/caspase-1/IL-1β-mediated and amplified inflammatory damage. Knockdown of CC chemokine receptor 2 gene (CCR2-/-), or administration of specific CCR2 inhibitor RS102895 (5 mg/kg per 12 h, i.p., one day before MIR and continuously until the end of the experiment) effectively reduced the area of myocardial infarction, and down-regulated inflammatory mediators and NLRP3/Caspase-1/IL-1β signaling. Mass cytometry confirmed that M2 macrophages played an important role during fibrosis, while macrophage-depleted mice exhibited significantly reduced transforming growth factor-β (Tgf-β) levels in heart tissue after MIR. In co-culture of macrophages with fibroblasts, treatment with recombinant mouse CCL2 stimulated macrophages to release a large amount of Tgf-β, and promoted the release of Col1α1 by fibroblasts. This effect was diminished in BMDMs from CCR2-/- mice. After knocking out or inhibiting CCR2-gene, the levels of Tgf-β were significantly reduced, as was the level of myocardial fibrosis, and cardiac function was protected. This study confirms that the acute injury to chronic fibrosis transition after MIR in mice is mediated by GMCSF/CCL2/CCR2 signaling in macrophages through NLRP3 inflammatory cascade and the phenotype switching.

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.

Myristoylated Protein Kinase C Epsilon Inhibitor Preserves Renal Function in a Mouse Model of Acute Bilateral Kidney Ischemia-Reperfusion Injury

Myristoylated Protein Kinase C Epsilon Inhibitor Preserves Renal Function in a Mouse Model of Acute Bilateral Kidney Ischemia-Reperfusion Injury

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.

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