Ischemia-reperfusion Model Research Articles

#829 Renoprotective effects of laxative linaclotide: inhibition of acute kidney injury and fibrosis in a rat model of renal ischemia-reperfusion

Abstract Background and Aims Acute kidney injury caused by renal ischemia/reperfusion (I/R) is a major clinical problem in many aspects of urology fields such as kidney transplantation and partial nephrectomy, but there is no effective treatment. Linaclotide, a guanylate cyclase C agonist clinically approved as a laxative, has recently been shown to be renoprotective in a chronic kidney disease (CKD) model. Therefore, the present study investigated the possibility that the renoprotective effects of linaclotide in renal I/R may extend beyond its gastrointestinal effects. Method The left renal pelvis of adult male Wistar rats was clamped for 45 minutes to induce renal I/R injury. Kidney tissue, colon, and blood were collected 24 hours and 14 days later. Linaclotide was administered for 14 days preoperatively and until postoperative tissue collection. Tissue sections were stained with standard histologic techniques such as HE, Sirius Red, F4/80, etc. As genes associated with I/R, TGF-β and related fibrosis markers α-SMA, MMP2, TIMP1 and inflammatory cytokines TNF, IL-1β and IL-6 were analyzed by quantitative PCR analysis. Results Serum creatinine levels decreased significantly after linaclotide administration, indicating improved renal function. Histologic examination showed less tubular damage and less collagen deposition on Sirius Red staining. Further analysis showed decreased expression of TGF-β and related fibrosis markers α-SMA, MMP2 and TIMP1, suggesting downregulation of the fibrotic TGF-β pathway by linaclotide. Furthermore, 1 day after I/R injury, linaclotide significantly reduced macrophage infiltration and suppressed key proinflammatory cytokines such as TNF, IL-1β, and IL-6. Conclusion These results suggest that linaclotide, with its established safety profile, could extend its benefits beyond gastrointestinal issues and potentially serve as a therapeutic intervention in many aspects of kidney surgeries. In addition, it could provide immediate and practical insights into the selection of laxatives for the management of patients with AKI or CKD, regardless of cause, and for those receiving dialysis or transplant therapy.

#407 Human platelet lysate enhanced angiogenic potential of extracellular vesicles derived from mesenchymal stem cells

Abstract Background and Aims Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have emerged as a promising regenerative therapy. However, their clinical application is hampered by the presence of xenogeneic components in the medium. In the present study, we aimed to decipher the regenerative properties of MSC-EVs generated under xeno-free conditions to favor the clinical translation of MSC-EVs. Method MSCs were isolated from human umbilical cord and expanded in fetal bovine serum (FBS) and clinical-grade human platelet lysate (HPL) respectively. MSC-EVs were isolated by differential centrifugation combined with size exclusion chromatography and characterized through transmission electron microscopy, nanoparticle tracking analysis, and exoview. Subsequently, a multi-omics approach, comprising transcriptomics, proteomics, and metabolomics, was employed to investigate the molecular cargo of the MSC-EVs. Finally, in vitro and in vivo functional assays were performed to assess the regenerative potential of MSC-EVs in acute kidney injury. Results Our study demonstrated that HPL promoted MSC-EVs production without compromising EVs characteristics. Multi-omics sequencing revealed the stability of HPL cultured MSC-EVs (H-EVs) from different umbilical cord donors and global functional alterations for MSC-EVs under different culture conditions. In comparison to FBS cultured MSC-EVs (F-EVs), the regenerative potential of H-EVs was enhanced especially angiogenesis associated with increased cargo expression. The in vitro studies demonstrated that H-EVs induced more tube-like structure formation and migration. Further, it significantly reduced kidney capillary sparsity in mice with renal ischemic-reperfusion model. Conclusion Our data provided a comprehensive understanding about H-EVs and demonstrated their potential as a safe and effective regenerative therapy, especially targeting angiogenesis-related disorders.

Maresin1 alleviates neuroinflammation by inhibiting caspase-3/ GSDME-mediated pyroptosis in mice cerebral ischemia-reperfusion model

ObjectiveTo explore the mechanism of Maresin1 in reducing cerebral ischemia-reperfusion injury. Materials and methodsMale C57BL/6 mice were randomly divided (n = 5 in each group), and focal middle cerebral artery occlusion (MCAO) model was used to simulate cerebral ischemia/reperfusion injury. TTC and the Longa score were used to detect the degree of neurological deficits. Western blot was used to detect the expression levels of GSDME, GSDME-N, caspase-3 and cleaved caspase-3 in cerebral ischemic penumbra tissue, and immunofluorescence was used to detect the expression levels of GSDME-N. The mRNA expression levels of GSDME and pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) were detected by RT-PCR. ResultsCompared with sham group, GSDME mRNA levels in MCAO group were significantly increased at 12 h and 24 h after reperfusion, and GSDME and GSDME-N significantly increased at 6–48 h after reperfusion. Compared with sham group, the percentage of infarct size, the Longa score, the mRNA expression levels of IL-1β, IL-6 and TNF-α, and GSDME, GSDME-N, caspase-3 and cleaved caspase-3 in MCAO group was significantly increased. Then, the percentage of infarct size and the Longa score significantly decreased after MaR1 administration, the mRNA expression levels of IL-1β and IL-6 downregulated, and GSDME, GSDME-N, caspase-3 and cleaved caspase-3 were also reduced. After administration of Z-DEVD-FMK(ZDF), the expression of caspase-3, cleaved caspase-3 and GSDME-N was decreased, which in MCAO+MaR1+ZDF group was not statistically significant compared with MCAO+ ZDF group. ConclusionMaresin1 alleviates cerebral ischemia/reperfusion injury by inhibiting pyroptosis mediated by caspase-3/GSDME pathway and alleviating neuroinflammation.

Targeted Restoration of GPX3 Attenuates Renal Ischemia/Reperfusion Injury by Balancing Selenoprotein Expression and Inhibiting ROS-mediated Mitochondrial Apoptosis.

Renal ischemia/reperfusion (IR) injury is the leading cause of acute kidney injury in both autologous and transplanted kidneys. Low-level glutathione peroxidase 3 (GPX3) is associated with renal IR injury. The exact mechanism of targeted GPX3 restoration in renal IR injury has yet to be determined. The distribution of GPX3 in different tissues and organs of the body was investigated. The level of GPX3 in renal IR injury was assessed. To confirm the action of GPX3 and its mechanisms, IR models were used to introduce adeno-associated virus 9 containing GPX3, as well as hypoxia/reoxygenation-exposed normal rat kidney cells that consistently overexpressed GPX3. Reverse molecular docking was used to confirm whether GPX3 was a target of ebselen. GPX3 is abundant in the kidneys and decreases in expression during renal IR injury. GPX3 overexpression reduced renal IR injury and protected tubular epithelial cells from apoptosis. Proteomics analysis revealed a strong link between GPX3 and mitochondrial signaling, cellular redox state, and different expression patterns of selenoproteins. GPX3 inhibited reactive oxygen species-induced mitochondrial apoptosis and balanced the disordered expression of selenoproteins. GPX3 was identified as a stable selenoprotein that interacts with ebselen. Ebselen enhanced the level of GPX3 and reduced IR-induced mitochondrial damage and renal dysfunction. Targeted restoration of GPX3 attenuates renal IR injury by balancing selenoprotein expression and inhibiting reactive oxygen species-mediated mitochondrial apoptosis, indicating that GPX3 could be a potential therapeutic target for renal IR injury.

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

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

Diabetic retinopathy is a ceramidopathy reversible by anti-ceramide immunotherapy

Diabetic retinopathy is a microvascular disease that causes blindness. Using acid sphingomyelinase knockout mice, we reported that ceramide generation is critical for diabetic retinopathy development. Here, in patients with proliferative diabetic retinopathy, we identify vitreous ceramide imbalance with pathologic long-chain C16-ceramides increasing and protective very long-chain C26-ceramides decreasing. C16-ceramides generate pro-inflammatory/pro-apoptotic ceramide-rich platforms on endothelial surfaces. To geo-localize ceramide-rich platforms, we invented a three-dimensional confocal assay and showed that retinopathy-producing cytokines TNFα and IL-1β induce ceramide-rich platform formation on retinal endothelial cells within seconds, with volumes increasing 2-logs, yielding apoptotic death. Anti-ceramide antibodies abolish these events. Furthermore, intravitreal and systemic anti-ceramide antibodies protect fromdiabetic retinopathy in standardized rodent ischemia reperfusion and streptozotocin models. These data support (1) retinal endothelial ceramide as a diabetic retinopathy treatment target, (2) early-stage therapy of non-proliferative diabetic retinopathy to prevent progression, and (3) systemic diabetic retinopathy treatment; and they characterize diabetic retinopathy as a "ceramidopathy" reversible by anti-ceramide immunotherapy.

A novel function and mechanism of ischemia-induced retinal astrocyte-derived exosomes for RGC apoptosis of ischemic retinopathy

Retinal ischemia is a common clinical event leading to retinal ganglion cell (RGC) death, resulting in irreversible vision loss. In the retina, glia-neuron communication is crucial for multiple functions and homeostasis. Extracellular vesicles, notably exosomes, play a critical role. The functions and mechanisms of retinal astrocyte-secreted exosomes remain unclear. Here, we isolated astrocyte-derived exosomes under hypoxia or normoxia and explored their role in an in vivo retinal ischemia-reperfusion (RIR) model. We found that hypoxia triggered astrocytes to produce a significantly increased number of exosomes, which could be internalized by RGCs in vivo or in vitro. Also, in the RIR model, the hypoxia-induced exosomes ameliorated the RIR injury and suppressed the RGC apoptosis. Furthermore, microRNA sequencing of retinal astrocyte-secreted exosomes revealed different patterns of exosomal miRNAs under hypoxia, particularly enriched with miR-329-5p. We verified that miR-329-5p was specifically bound to MAPK8 mRNA, and subsequent JNK-pathway molecules were downregulated. We anticipated that the miR-329-5p/JNK pathway is a key to suppressing RGC apoptosis and preventing RIR injury. Such findings provided insights into the therapeutic potential of hypoxia-induced astrocyte-secreted exosomes and the miR-329-5p for treating retina ischemic diseases.

Urotensin II system contributes to ischemic acute kidney injury in neonatal pigs

Urotensin II (UII) and UII-related peptide (URP) and their receptor, UT, comprise the UII system. Although UII is conserved across all vertebrates and shares a cyclic hexapeptide core-sequence motif of CFWKYC, there are differences in N-terminal amino acid sequences between species. The kidney is a significant source of UII, the level of which is amplified in infants with chronic kidney disease. We have previously shown that human UII increases renal vascular resistance (RVR) and reduces renal blood flow in neonatal pigs. However, the effect of pig UII (pUII) on renal microcirculation remains unclear. Since the mechanisms of renal ischemia-reperfusion (IR) injury include kidney hypoperfusion, increased activity of the UII system may contribute to ischemic acute kidney injury (AKI). Here, we demonstrate that kidney tissue UII, URP, and UT and renal vascular UT expression levels are higher in neonatal pigs than in adults. Intrarenal artery infusion of pUII reduced kidney perfusion and increased RVR, which was reversed by urantide, a peptide UT inhibitor. One hour of renal ischemia, followed by 8 hours of reperfusion, did not alter kidney tissue UT but upregulated kidney tissue UII and URP and renal vascular UT expression levels. Urantide mitigated renal IR-induced increase in AKI biomarkers. Urantide also attenuated renal IR-induced increases in serum interleukin-1beta, interleukin-10, interferon-α, and morphological kidney injury. The enzyme that converts prepro UII to active UII has been proposed to be serine protease furin. Kidney tissue expression of furin is higher in neonatal pigs compared with adults. Renal IR also upregulated furin expression in neonatal pig kidneys. Exposure of primary neonatal pig renal epithelial cells to the cellular model of IR (cIR) increased furin levels. cIR also increased UII production in the cells, an effect attenuated by furin inhibitor SS3. These findings suggest that in pigs, 1) the UII system is upregulated in immature kidneys, 2) renal IR upregulates furin, UII, and URP in kidney tissues and UT in renal blood vessels of neonates, 3) ischemic activation of furin promotes UII biosynthesis by renal epithelial cells, and 4) pharmacological inhibition of UT mitigates renal IR-induced AKI. We conclude that the UII systems may contribute to IR-induced neonatal renal insuffciency. NIH R01DK120595 R01DK127625. 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.

Beneficial Effect of Heat Treatment on the Exercise Pressor Reflex in Hindlimb Ischemia-Reperfusion: Potential Role of P2X3

PURPOSE: In peripheral artery disease (PAD), a greater blood pressure (BP) response during exercise causes cardiovascular and cerebrovascular risks. The exercise pressor reflex (EPR) is a key factor for why BP is exaggerated in PAD patients. Thus, we examined the effect of heat treatment (HT) with two temperature increments in skeletal muscle: 1.5 and 3oC on the EPR response following limb ischemia-reperfusion (IR) injury, one of the most common pathological conditions seen in PAD. In addition, the P2X3 (an ATP-sensitive receptor) in the muscle afferent dorsal root ganglion (DRG) was also evaluated. We hypothesized that IR upregulates the BP response to static muscle contraction and the protein expression of P2X3 in muscle afferent nerves. HT attenuates those exaggerated responses. METHODS: An experimental IR model was induced by 6 hours of ischemia followed by 18 hours of reperfusion in rats (IR rats). For HT groups, three HT sessions (muscle temperature increased by 1.5 or 3oC) for 30 mins/each time were applied. EPR response was evoked by static muscle contraction (30s). Protein expression of the P2X3 receptor in DRGs was examined. Data are presented as mean ± standard deviation. Results: The mean arterial pressure (MAP) response to the static muscle contraction was significantly exaggerated in rats of IR 18h (vs. Sham, P=0.018). With increasing Tm by 1.5°C, there was a promising trend that thus exaggerated BP response was attenuated (IR 18h + HT 1.5°C, n=5 vs. IR 18h rats, n=5, P=0.08). Meanwhile, the exaggerated BP response was significantly attenuated with the Tm increasing by 3°C (IR 18h + HT 3°C, n=5, vs. IR 18h rats, n=5, P=0.032). The expression of the P2X3 receptor was significantly enhanced in the DRGs of IR 18h rats (n=4, p<0.01 vs. sham, n=6). The upregulated P2X3 was suppressed in the DRGs of IR 18h rats +HT of 1.5°C (n=3, p<0.01 vs. IR 18h, n=4) and there was a promising trend that upregulated P2X3 was suppressed in the DRGs of IR 18h rats +HT of 3°C (n=3, P=0.079 vs. IR 18h, n=4). CONCLUSION: IR injury leads to upregulation of EPR response and this effect was attenuated by HT. The P2X3 signaling pathways are likely involved in the beneficial regulatory effect of HT on EPR in IR. Further data collection will be performed to test this conclusion. Supported by NIH R01 HL141198 & HL164571; AHA GRANT # 940567/Lu Qin/2022; and College of Medicine DOM Innovation and Inspiration Award. The authors sincerely thank Chunying Yang for the excellent technical assistance. 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.

Inflammation in cerebral ischemia reperfusion improved by avanafil via nod-like receptor protein-3 inflammasome: an experimental study in rats

ABSTRACT Objective The aim of study was to investigate the effect of avanafil, a second-generation phosphodiesterase-5 (PDE5) inhibitor, on cerebral ischemia reperfusion (CI/R) model. Methods 32 male albino Wistar rats were used. Four groups were constituted, as I: the healthy (sham), II: the CI/R group, III: the CI/R +I 10 mg/kg avanafil group, and IV: the CI/R + 20 mg/kg avanafil group. Avanafil was administered twice via oral gavage, first shortly after ischemia reperfusion and once more after 12 h. The rats were euthanized after 24 h. Histopathological and Real Time PCR analyzes were performed on cerebral tissues. Results IL-1β, NLRP3 and TNF-α mRNA expressions were statistically higher in the CI/R group when compared to healthy (sham) group. Conversely, the IL-1β, NLRP3, and TNF-α mRNA expressions were significantly decreased in both of the avanafil-treated groups when compared to CI/R group. Histopathological results showed that both doses of avanafil also decreased cellular damage in cerebral tissue that occurred after CI/R. Conclusion Avanafil, was found to have ameliorated inflammatory response and cellular injury caused by CI/R. The mRNA expression of IL-1β, NLRP3, and TNF-α decreased in the I/R groups and approached the control group levels with a high dose of avanafil.

Oxidative medicine and cellular longevity the role and mechanism of NCOA4 in ferroptosis induced by intestinal ischemia reperfusion

BackgroundFerroptosis is an iron-dependent and cystathione-non-dependent non-apoptotic cell death characterized by elevated intracellular free iron levels and reduced antioxidant capacity, leading to the accumulation of lipid peroxides. Nuclear receptor coactivator 4 (NCOA4) mediates ferritinophagy, increasing labile iron levels, which can result in oxidative damage. However, the specific mechanism of NCOA4-mediated ferritinophagy in intestinal ischemia–reperfusion and the underlying mechanisms have not been reported in detail. Object1. To investigate the role of NCOA4 in ferroptosis of intestinal epithelial cells induced by II/R injury in mouse. 2. To investigate the mechanism of action of NCOA4-induced ferroptosis. Methods1. Construct a mouse II/R injury model and detect ferroptosis related markers such as HE staining, immunohistochemistry, ELISA, and WB methods.2. Detect expression of NCOA4 in the intestine of mouse with II/R injury model and analyze its correlation with intestinal ferroptosis in mouse with II/R injury model.3. Construct an ischemia–reperfusion model at the cellular level through hypoxia and reoxygenation, and overexpress/knockdown NCOA4 to detect markers related to ferroptosis. Based on animal experimental results, analyze the correlation and mechanism of action between NCOA4 and intestinal epithelial ferroptosis induced by II/R injury in mouse. Results1. Ferroptosis occurred in the intestinal epithelial cells of II/R-injured mouse, and the expression of critical factors of ferroptosis, ACSL4, MDA and 15-LOX, was significantly increased, while the levels of GPX4 and GSH were significantly decreased. 2. The expression of NCOA4 in the intestinal epithelium of mouse with II/R injure was significantly increased, the expression of ferritin was significantly decreased, and the level of free ferrous ions was significantly increased; the expression of autophagy-related proteins LC3 and Beclin-1 protein was increased, and the expression of P62 was decreased, and these changes were reversed by autophagy inhibitors. 3. Knockdown of NCOA4 at the cellular level resulted in increased ferritin expression and decreased ferroptosis, and CO-IP experiments suggested that NCOA4 can bind to ferritin, which suggests that NCOA4 most likely mediates ferritinophagy to induce ferroptosis. ConclusionThis thesis explored the role of NCOA4 in II/R injury in mice and the mechanism of action. The research results suggest that NCOA4 can mediate ferritinophagy to induce ferroptosis during II/R injury. This experiment reveals the pathological mechanism of II/R injury and provides some scientific basis for the development of drugs for the treatment of II/R injury based on the purpose of alleviating ferroptosis.

A highly potent, orally bioavailable pyrazole-derived cannabinoid CB2 receptor-selective full agonist for in vivo studies.

The cannabinoid CB2 receptor (CB2R) is a potential therapeutic target for distinct forms of tissue injury and inflammatory diseases. To thoroughly investigate the role of CB2R in pathophysiological conditions and for target validation in vivo, optimal pharmacological tool compounds are essential. Despite the sizable progress in the generation of potent and selective CB2R ligands, pharmacokinetic parameters are often neglected for in vivo studies. Here, we report the generation and characterization of a tetra-substituted pyrazole CB2R full agonist named RNB-61 with high potency (K i 0.13-1.81 nM, depending on species) and a peripherally restricted action due to P-glycoprotein mediated efflux from the brain. 3H and 14C labelled RNB-61 showed apparent K d values < 4 nM towards human CB2R in both cell and tissue experiments. The >6000-fold selectivity over CB1 receptors and negligible off-targets in vitro, combined with high oral bioavailability and suitable systemic pharmacokinetic (PK) properties, prompted the assessment of RNB-61 in a mouse ischemia-reperfusion model of acute kidney injury (AKI) and in a rat model of chronic kidney injury/inflammation and fibrosis (CKI) induced by unilateral ureteral obstruction. RNB-61 exerted dose-dependent nephroprotective and/or antifibrotic effects in the AKI/CKI models. Thus, RNB-61 is an optimal CB2R tool compound for preclinical in vivo studies with superior biophysical and PK properties over generally used CB2R ligands.

Penehyclidine hydrochloride alleviates lung ischemia-reperfusion injury by inhibiting pyroptosis

ObjectiveThe aim of this research was to examine how penehyclidine hydrochloride (PHC) impacts the occurrence of pyroptosis in lung tissue cells within a rat model of lung ischemia-reperfusion injury.MethodsTwenty-four Sprague Dawley (SD) rats, weighing 250 g to 270 g, were randomly distributed into three distinct groups as outlined below: a sham operation group (S group), a control group (C group), and a test group (PHC group). Rats in the PHC group received a preliminary intravenous injection of PHC at a dose of 3 mg/kg. At the conclusion of the experiment, lung tissue and blood samples were collected and properly stored for subsequent analysis. The levels of malondialdehyde, superoxide dismutase, and myeloperoxidase in the lung tissue, as well as IL-18 and IL-1β in the blood serum, were assessed using an Elisa kit. Pyroptosis-related proteins, including Caspase1 p20, GSDMD-N, and NLRP3, were detected through the western blot method. Additionally, the dry-to-wet ratio (D/W) of the lung tissue and the findings from the blood gas analysis were also documented.ResultsIn contrast to the control group, the PHC group showed enhancements in oxygenation metrics, reductions in oxidative stress and inflammatory reactions, and a decrease in lung injury. Additionally, the PHC group exhibited lowered levels of pyroptosis-associated proteins, including the N-terminal segment of gasdermin D (GSDMD-N), caspase-1p20, and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3).ConclusionPre-administration of PHC has the potential to mitigate lung ischemia-reperfusion injuries by suppressing the pyroptosis of lung tissue cells, diminishing inflammatory reactions, and enhancing lung function. The primary mechanism behind anti-pyroptotic effect of PHC appears to involve the inhibition of oxidative stress.

Effect of electroacupuncture on proBDNF/mBDNF and synaptic plasticity in rats with learning and memory impairment after cerebral ischemia-reperfusion.

To observe the effect of electroacupuncture (EA) at "Baihui" (GV20) and "Shenting" (GV24) on the rats' behavior and the transforming precursor of brain-derived neurotrophic factor (proBDNF) into mature brain-derived neurotrophic factor (mBDNF) in the hippocampus of rats with learning and memory impairment induced by cerebral ischemia-reperfusion (IR), so as to explore its mechanisms underlying improvement of learning and memory ability. SD rats were randomly divided into blank, sham operation, model, and EA groups, with 6 rats in each group. The model of IR was established by occlusion of the middle cerebral artery. EA (1 Hz/20 Hz) was applied to GV24 and GV20 for 30 min, once daily for 14 days. The neurological function was evaluated according to the Zea Longa's score criteria 24 h after modeling and after intervention. Morris water maze test was used to detect the learning and memory function of the rats. TTC staining was used to evaluate the cerebral infarction volume on the affected side. The protein expression levels of proBDNF, mBDNF, tissue plasminogen activator (tPA), tyrosine kinase receptor B (TrkB) and p75 neurotrophin receptor (p75NTR) in hippocampal tissue were detected by Western blot. Compared with the sham operation group, the neurological function score, the percentage of cerebral infarction volume and the expression levels of proBDNF and p75NTR protein in hippocampus were increased (P<0.01), while the times of crossing the original platform and the total distance in the target quadrant, the expression levels of mBDNF, TrkB and tPA protein and the ratio of mBDNF/proBDNF were decreased (P<0.01, P<0.05) in the model group. Compared with the model group, the neurological function score, the percentage of cerebral infarction volume, and the expression levels of proBDNF and p75NTR protein in hippocampus were decreased (P<0.01, P<0.05), while the times of crossing the original platform, the total distance in the target quadrant, and the expression levels of mBDNF, TrkB and tPA protein and the ratio of mBDNF/proBDNF were increased (P<0.05, P<0.01) in the EA group. EA can alleviate learning and memory impairment in IR rats, which may be related to its function in up-regulating the expression of tPA protein and promoting the transformation of proBDNF to mBDNF, thus improving the synaptic plasticity.

Bile acids attenuate hepatic inflammation during ischemia/reperfusion injury

Background & AimsPersistent cholestasis has been associated with poor prognosis after orthotopic liver transplantation (OLT). In this study, we aimed to investigate how the accumulation of tauro-beta-muricholic acid (TβMCA), resulting from the reprogramming of bile acid (BA) metabolism during liver ischemia/reperfusion (IR) stress, attenuates liver inflammation. MethodsIngenuity Pathway Analysis (IPA) was performed using transcriptome data from a murine hepatic IR model. Three different models of hepatic IR (liver warm IR, bile duct separation-IR, common bile duct ligation-IR) were employed. We generated AAV-transfected mice and CD11b-DTR mice to assess the role of BAs in regulating the myeloid S1PR2-GSDMD axis. Hepatic BA levels were analyzed using targeted metabolomics. Finally, the correlation between the reprogramming of BA metabolism and hepatic S1PR2 levels was validated through RNA-seq of human OLT biopsies. ResultsWe found that BA metabolism underwent reprogramming in murine hepatocytes under IR stress, leading to increased synthesis of TβMCA, catalyzed by the enzyme CYP2C70. The levels of hepatic TβMCA were negatively correlated with the severity of hepatic inflammation, as indicated by the serum IL-1β levels. Inhibition of hepatic CYP2C70 resulted in reduced TβMCA production, which subsequently increased serum IL-1β levels and exacerbated IR injury. Moreover, our findings suggested that TβMCA could inhibit canonical inflammasome activation in macrophages and attenuate inflammatory responses in a myeloid-specific S1PR2-GSDMD-dependent manner. Additionally, Gly-βMCA, a derivative of TβMCA, could effectively attenuate inflammatory injury in vivo and inhibit human macrophage pyroptosis in vitro. ConclusionsIR stress orchestrates hepatic BA metabolism to generate TβMCA, which attenuates hepatic inflammatory injury by inhibiting the myeloid S1PR2-GSDMD axis. Bile acids have immunomodulatory functions in liver reperfusion injury that may guide therapeutic strategies. Impact and implicationsOur research reveals that liver IR stress triggers reprogramming of BA metabolism. This functions as an adaptive mechanism to mitigate inflammatory injury by regulating the S1PR2-GSDMD axis, thereby controlling the release of IL-1β from macrophages. Our results highlight the crucial role of bile acids in regulating hepatocyte-immune cell crosstalk, which demonstrates an immunomodulatory function in liver reperfusion injury that may guide therapeutic strategies targeting bile acids and their receptors.

Effects of Trehalose Preconditioning on H9C2 Cell Viability and Autophagy Activation in a Model of Donation after Circulatory Death for Heart Transplantation.

Donation after circulatory death (DCD) is a promising strategy for alleviating donor shortage in heart transplantation. Trehalose, an autophagy inducer, has been shown to be cardioprotective in an ischemia-reperfusion (IR) model; however, its role in IR injury in DCD remains unknown. In the present study, we evaluated the effects of trehalose on cardiomyocyte viability and autophagy activation in a DCD model. In the DCD model, cardiomyocytes (H9C2) were exposed to 1 h warm ischemia, 1 h cold ischemia, and 1 h reperfusion. Trehalose was administered before cold ischemia (preconditioning), during cold ischemia, or during reperfusion. Cell viability was measured using the Cell Counting Kit-8 after treatment with trehalose. Autophagy activation was evaluated by measuring autophagy flux using an autophagy inhibitor, chloroquine, and microtubule-associated protein 1A/1B light chain 3 B (LC3)-II by western blotting. Trehalose administered before the ischemic period (trehalose preconditioning) increased cell viability. The protective effects of trehalose preconditioning on cell viability were negated by chloroquine treatment. Furthermore, trehalose preconditioning increased autophagy flux. Trehalose preconditioning increased cardiomyocyte viability through the activation of autophagy in a DCD model, which could be a promising strategy for the prevention of cardiomyocyte damage in DCD transplantation.

Mechanism of pterostilbene in improving myocardial injury after percutaneous coronary intervention through being targeted on miR-26a-5p

Our study aimed to discuss the mechanism of pterostilbene in improving myocardial injury after percutaneous coronary intervention (PCI) through targeting miR-26a-5p. The myocardial cells were isolated from C57BL/6 mice. They were frozen in liquid nitrogen for reservation after they were passaged. The cell transfection was performed with miR-26a-5p depressor or lipofectamine 3000. The Ischemia-Reperfusion (I/R) model was established. They were divided into several sets including control set, I/R set, miR-26a-5p imitative set, miR-26a-5p depressor set and pterostilbene set. The presentation of GAPDH and miR-26a-5p was monitored with Real-time PCR. The proliferation was tested with Flow Cytometry (FCM). Caspase-3 activity was tested with spectrophotometry. The protein expression was monitored with Western blot assay. The level of IL-6 and TNF-α was tested with ELISA method. There was abnormal miR-26a-5p expression in the I/R model. The survival rate of myocardial cells was improved by upregulating miR-26a-5p. And expression of apoptotic protein as p53 was reduced and SOD activity was increased. Reactive oxygen species (ROS) level was reduced. The level of IL-6 and TNF-α was restrained. miR-26a-5p in I/R model was increased with pterostilbene notably. The myocardial injury was improved by pterostilbene through regulating miR-26a-5p. It could provide a brand-new scheme for treating myocardial injury after PCI.

Evaluation of the effect of enriched hydrogen saline solution on distant organ (lung) damage in skeletal muscle ischemia reperfusion in rats.

Ischemia-reperfusion (IR) injury is a major concern that frequently occurs during vascular surgeries. Hydrogen-rich saline (HRS) solution exhibits antioxidant and anti-inflammatory properties. This study aimed to examine the effects of HRS applied before ischemia in the lungs of rats using a lower extremity IR model. After approval was obtained from the ethics committee, 18 male Wistar albino rats weighing 250-280 g were randomly divided into three groups: control (C), IR and IR-HRS. In the IR and IR-HRS groups, an atraumatic microvascular clamp was used to clamp the infrarenal abdominal aorta, and skeletal muscle ischemia was induced. After 120 min, the clamp was removed, and reperfusion was achieved for 120 min. In the IR-HRS group, HRS was administered intraperitoneally 30 min before the procedure. Lung tissue samples were examined under a light microscope and stained with hematoxylin-eosin (H&E). Malondialdehyde (MDA) levels, total sulfhydryl (SH) levels, and histopathological parameters were evaluated in the tissue samples. MDA and total SH levels were significantly higher in the IR group than in the control group (p < 0.0001 and p = 0.001, respectively). MDA and total SH levels were significantly lower in the IR-HRS group than in the IR group (p < 0.0001 and p = 0.013, respectively). A histopathological examination revealed that neutrophil infiltration/aggregation, alveolar wall thickness, and total lung injury score were significantly higher in the IR group than in the control group (p < 0.0001, p = 0.001, and p < 0.0001, respectively). Similarly, alveolar wall thickness and total lung injury scores were significantly higher in the IR-HRS group than in the control group (p = 0.009 and p = 0.004, respectively). A statistically significant decrease was observed in neutrophil infiltration/aggregation and total lung injury scores in the IR-HRS group compared to those in the IR group (p = 0.023 and p = 0.022, respectively). HRS at a dose of 20 mg/kg, administered intraperitoneally 30 min before ischemia in rats, reduced lipid peroxidation and oxidative stress, while also reducing IR damage in lung histopathology. We believe that HRS administered to rats prior to IR exerts a lung-protective effect.

Restoring Mitochondrial Function and Muscle Satellite Cell Signaling: Remedies against Age-Related Sarcopenia.

Sarcopenia has a complex pathophysiology that encompasses metabolic dysregulation and muscle ultrastructural changes. Among the drivers of intracellular and ultrastructural changes of muscle fibers in sarcopenia, mitochondria and their quality control pathways play relevant roles. Mononucleated muscle stem cells/satellite cells (MSCs) have been attributed a critical role in muscle repair after an injury. The involvement of mitochondria in supporting MSC-directed muscle repair is unclear. There is evidence that a reduction in mitochondrial biogenesis blunts muscle repair, thus indicating that the delivery of functional mitochondria to injured muscles can be harnessed to limit muscle fibrosis and enhance restoration of muscle function. Injection of autologous respiration-competent mitochondria from uninjured sites to damaged tissue has been shown to reduce infarct size and enhance cell survival in preclinical models of ischemia-reperfusion. Furthermore, the incorporation of donor mitochondria into MSCs enhances lung and cardiac tissue repair. This strategy has also been tested for regeneration purposes in traumatic muscle injuries. Indeed, the systemic delivery of mitochondria promotes muscle regeneration and restores muscle mass and function while reducing fibrosis during recovery after an injury. In this review, we discuss the contribution of altered MSC function to sarcopenia and illustrate the prospect of harnessing mitochondrial delivery and restoration of MSCs as a therapeutic strategy against age-related sarcopenia.

CX3CR1 deficiency promotes resolution of hepatic ischemia-reperfusion injury by regulating homeostatic function of liver infiltrating macrophages

Hepatic ischemia-reperfusion injury(HIRI) remains to be an unsolved risk factor that contributes to organ failure after liver surgery. Our clinical retrospective study showed that lower donor liver CX3-C chemokine receptor-1(CX3CR1) mRNA expression level were correlated with upregulated pro-resolved macrophage receptor MERTK, as well as promoted restoration efficiency of allograft injury in liver transplant. To further characterize roles of CX3CR1 in regulating resolution of HIRI, we employed murine liver partial warm ischemia-reperfusion model by Wt &Cx3cr1−/− mice and the reperfusion time was prolonged from 6 h to 4–7 days. Kupffer cells(KCs) were depleted by clodronate liposome(CL) in advance to focus on infiltrating macrophages, and repopulation kinetics were determined by FACS, IF and RNA-Seq. CX3CR1 antagonist AZD8797 was injected i.p. to interrogate potential pharmacological therapeutic strategies. In vitro primary bone marrow macrophages(BMMs) culture by LXR agonist DMHCA, as well as molecular and functional studies, were undertaken to dissect roles of CX3CR1 in modulating macrophages cytobiological development and resolutive functions. We observed that deficiency or pharmacological inhibition of CX3CR1 facilitated HIRI resolution via promoted macrophages migration in CCR1/CCR5 manner, as well as enhanced MerTK-mediated efferocytosis. Our study demonstrated the critical roles of CX3CR1 in progression of HIRI and identified it as a potential therapeutic target in clinical liver transplantation.