Rat Model Of Acute Kidney Injury Research Articles

Vancomycin-induced acute kidney injury in rats: beneficial effects deriving from the co-administration of tadalafil or vitamin C

Background: Vancomycin (VAN) is widely employed in clinical settings for the treatment of severe infections attributable to multi-resistant bacteria, with a notable emphasis on Gram-positive strains. However, its therapeutic usage is significantly hampered by the potential for acute kidney injury (AKI); specifically, the nephrotoxic effects it can exert. In controlled experimental studies, the intraperitoneal (i.p.) administration of VAN at a dose of 400 mg/kg/day over a consecutive seven-day period has been shown to induce considerable AKI in rats. In addressing this concern, vitamin C (VC), recognized traditionally for its antioxidant properties, has been utilized to mitigate various forms of organ damage and inflammatory responses, primarily by diminishing oxidative stress and attenuating inflammation. Concurrently, tadalafil (TAD), a phosphodiesterase type-5 inhibitor commonly associated with the treatment of erectile dysfunction, is also noted for its beneficial anti-inflammatory and antioxidant effects, alongside vasodilatory properties. Aim: This study was designed in order to investigate the protective capabilities of TAD or VC against the VAN-induced nephrotoxic effects in a rat model of AKI. Methodology: A total of 24 male albino Wistar rats were allocated into four distinct groups for the purpose of comparative analysis. Following treatment, both kidney and blood samples were obtained for further evaluation. The study randomized the rats into four categories: group 1 served as the control group, group 2 received VAN at a dosage of 400 mg/kg (via an i.p. injection on a daily basis), group 3 was administered VAN (400 mg/kg; i.p., daily) in conjunction with TAD at a dose of 5 mg/kg daily, and group 4 was given VAN (400 mg/kg; i.p., daily) alongside VC at a dosage of 200 mg/kg daily. Results: Evaluations included the measurement of renal function indicators such as the serum levels of urea, of creatinine, and the creatinine clearance. Additionally, the analysis involved the assessment of antioxidant markers in renal tissue homogenates, including malondialdehyde (MDA), glutathione, and superoxide dismutase. To further elucidate the inflammatory response, indices such as the levels of the tumor necrosis factor-alpha, the interleukins (IL)-1β and IL-6, and the nuclear factor-κB were evaluated within the renal tissue homogenate samples of the studied rats. The administration of VAN resulted in a marked elevation of renal biomarkers and inflammatory indices, alongside a significant reduction in antioxidant levels, with an exception for MDA (which exhibited increased levels); these changes reached statistical significance (p<0.05) when measured against the control group. In contrast, the supplementation with TAD or VC was effective in significantly lowering the serum levels of both renal and inflammatory indicators when compared to the group treated solely with VAN. Furthermore, antioxidant measurements improved, alongside a reduction in MDA levels, thereby demonstrating significant differences (p<0.05). Conclusion: The findings of this study reveal that both TAD and VC provide a degree of renal protection against the VAN-induced damage by enhancing kidney function markers and, concurrently, lessening oxidative stress and inflammatory responses associated with nephrotoxicity.

Dexmedetomidine ameliorates acute kidney injury by regulating mitochondrial dynamics via the α2-AR/SIRT1/PGC-1α pathway activation in rats

BackgroundSepsis-associated acute kidney injury (AKI) is a serious complication of systemic infection with high morbidity and mortality in patients. However, no effective drugs are available for AKI treatment. Dexmedetomidine (DEX) is an alpha 2 adrenal receptor agonist with antioxidant and anti-apoptotic effects. This study aimed to investigate the therapeutic effects of DEX on sepsis-associated AKI and to elucidate the role of mitochondrial dynamics during this process.MethodsA lipopolysaccharide (LPS)-induced AKI rat model and an NRK-52E cell model were used in the study. This study investigated the effects of DEX on sepsis-associated AKI and the molecular mechanisms using histologic assessment, biochemical analyses, ultrastructural observation, western blotting, immunofluorescence, immunohistochemistry, qRT-PCR, flow cytometry, and si-mRNA transfection.ResultsIn rats, the results showed that administration of DEX protected kidney structure and function from LPS-induced septic AKI. In addition, we found that DEX upregulated the α2-AR/SIRT1/PGC-1α pathway, protected mitochondrial structure and function, and decreased oxidative stress and apoptosis compared to the LPS group. In NRK-52E cells, DEX regulated the mitochondrial dynamic balance by preventing intracellular Ca2+ overloading and activating CaMKII.ConclusionsDEX ameliorated septic AKI by reducing oxidative stress and apoptosis in addition to modulating mitochondrial dynamics via upregulation of the α2-AR/SIRT1/PGC-1α pathway. This is a confirmatory study about DEX pre-treatment to ameliorate septic AKI. Our research reveals a novel mechanistic molecular pathway by which DEX provides nephroprotection.

Protection Effect of Soy Isoflavones (Genistein and Daidzein) on Hematologic Parameters in Acute Kidney Injury

Background: Acute kidney injury (AKI) is a severe, high-morbidity condition with limited effective preventative and therapeutic strategies despite advancements in understanding and treatment. Specific Background: Rhabdomyolysis-induced acute kidney injury (AKI) presents significant challenges in renal research, but soy isoflavones, particularly GN and DZ, have shown potential in mitigating oxidative stress and inflammation. Knowledge Gap: Soy isoflavones, while potentially providing renal protection, their impact on renal and hematologic parameters in glycerol-induced AKI models has not been thoroughly studied. Aims: The study evaluated the effectiveness of soy isoflavones in regulating renal and hematologic parameters in a glycerol-induced AKI rat model, assessing their potential as therapeutic agents. Results: The study involving adult female Wistar rats showed that pretreatment with glycerol or dihydroxystilbene significantly reduced urinary β2-microglobulin, albumin, BUN, and serum creatinine levels in the AKI-induced group, reversing hematological changes. Novelty: The study explores the protective effects of soy isoflavones on renal function and hematologic parameters in AKI, highlighting GN's superior efficacy over DZ. Implications: Soy isoflavones, particularly GN, may be potential preventive or therapeutic strategies for AKI caused by rhabdomyolysis, warranting further research for clinical applications. Highlights: GN and DZ reduce kidney damage in glycerol-induced AKI. GN is more effective than DZ in kidney and blood parameters. Soy isoflavones could treat or prevent AKI. Keywords: Acute kidney injury, soy isoflavones, glycerol-induced AKI, renal protection, hematologic parameters

Hollow mesoporous Prussian blue nanoenzymes as Rapamycin carrier for targeted treatment of ischemia/reperfusion-induced acute kidney injury through pro-mitophagy and oxidative stress alleviation

The kidney’s abundant mitochondrial content and substantial oxygen requirements make it particularly vulnerable to a series of detrimental events following ischemia/reperfusion (I/R). These events encompass oxidative stress, mitochondrial impairment, depletion of adenosine triphosphate (ATP), and inflammation, cumulatively leading to acute kidney injury (AKI). Currently, no approved therapy beyond supportive care is available for AKI. While numerous studies have focused on neutralizing pre-existing reactive oxygen species (ROS) to mitigate AKI, insufficient attention has been paid to addressing the root causes of ROS. Here, we prepared Rapamycin (Rapa)-loaded hollow mesoporous Prussian blue nanoparticles (HMPB-Rapa) and grafted injured renal-targeted hyaluronic acid (HA) onto HMPB-Rapa (HA-HMPB-Rapa), which effectively scavenge pre-existing ROS and the source (massive damaged mitochondria) through the dual function of HMPB carrier and Rapa, thus preventing the further burst of ROS. In the I/R-induced AKI rat model, a single-dose of HA-HMPB-Rapa 6 h after I/R injury effectively inhibited oxidative stress and inflammation, protected renal cells from apoptotic damage, as well as ultimately restored renal function, and attenuated pathological changes. Mechanistically, HA-HMPB-Rapa cleared damaged mitochondria by activating the pro-mitophagy signaling pathway (PINK-1/Parkin-P62-LC3), cutting off the conduction in the intrinsic apoptotic pathway mediated by the Bax-Cyt-c-Cleaved Casp-3 signaling axis, and reduced the expression of renal tubular marker kidney injury molecule-1. HA-HMPB-Rapa represents an exciting new avenue for the treatment of diseases related to I/R-induced injury.

#604 Oral administration of UNI-494 ameliorates acute kidney injury in a rat model of delayed graft function

Abstract Background and Aims There are no FDA approved drugs for the treatment of acute kidney injury (AKI), which affects 10-15% of hospitalized patients and often results in renal transplantation or lifelong dialysis. UNI-494 is a novel nicotinamide ester derivative and selective mitochondrial ATP-sensitive potassium channel activator that may be beneficial for several disease states, including AKI. We present results from a study evaluating the in vivo efficacy of oral (PO) UNI-494 in the unilateral renal ischemia-reperfusion (I/R) rat model of AKI, which is a well-established model of delayed graft function (DGF) (Cavaille-Coll, 2013). Method Rats were anesthetized, the right kidney was removed, and I/R was induced in three groups of rats by clamping the renal vessels in the left kidney for 30 minutes; a fourth group had no surgery (sham group) without clamping the renal vessels. 50 mg/kg or 100 mg/kg UNI-494 were administered PO 30 minutes prior to I/R. One I/R group and the sham group were not treated. After 24 hours of reperfusion in metabolic cages, blood samples were collected for serum creatinine (sCr), and urinary samples were collected for albumin-creatinine ratio (ACR) and the tubular injury marker neutrophil gelatinase-associated lipocalin (NGAL). The clamped left kidney was collected and processed for histology for tubular injury scores. Results In this study, I/R induced significant increases of sCr, ACR, NGAL, and proximal convoluted tubular injury scores in the vehicle treated I/R group vs No I/R sham group. A single PO dose of UNI-494 at 50 mg/kg/PO or 100 mg/kg/PO reduced the kidney functional markers sCr and ACR, the tubular injury marker (NGAL), and proximal tubular injury scores (all p < 0.001, Fig. 1). Conclusion The results indicate that UNI-494 dose dependently prevented AKI markers and proximal tubular injury in a rat model of AKI and therefore is a potential candidate for the prevention of DGF and other AKI clinical conditions.

Unlocking renal Restoration: Mesaconine from Aconitum plants restore mitochondrial function to halt cell apoptosis in acute kidney injury

Acute kidney injury (AKI) is characterized by a sudden decline in renal function. Traditional Chinese medicine has employed Fuzi for kidney diseases; however, concerns about neurotoxicity and cardiotoxicity have constrained its clinical use. This study explored mesaconine, derived from processed Fuzi, as a promising low-toxicity alternative for AKI treatment. In this study, we assessed the protective effects of mesaconine in gentamicin (GM)-induced NRK-52E cells and AKI rat models in vitro and in vivo, respectively. Mesaconine promotes the proliferation of damaged NRK-52E cells and down-regulates intracellular transforming growth factor β1 (TGF-β1) and kidney injury molecule 1 (KIM-1) to promote renal cell repair. Concurrently, mesaconine restored mitochondrial morphology and permeability transition pores, reversed the decrease in mitochondrial membrane potential, mitigated mitochondrial dysfunction, decreased ATP production, inhibited inflammatory factor release, and reduced early apoptosis rates. In vivo, GM-induced AKI rat models exhibited elevated AKI biomarkers, in which mesaconine was effectively reduced, indicating improved renal function. Mesaconine enhanced superoxide dismutase activity, reduced malondialdehyde content, alleviated inflammatory infiltrate, mitigated tubular and glomerular lesions, and downregulated NF-κB (nuclear factor-κb) p65 expression, leading to decreased tumor necrosis factor-α (TNF-α) and IL-1β (interleukin-1β) levels in GM-induced AKI animals. Furthermore, mesaconine inhibited the expression of renal pro-apoptotic proteins (Bax, cytochrome c, cleaved-caspase 9, and cleaved-caspase 3) and induced the release of the anti-apoptotic protein bcl-2, further suppressing apoptosis. This study highlighted the therapeutic potential of mesaconine in GM-induced AKI. Its multifaceted mechanisms, including the restoration of mitochondrial dysfunction, anti-inflammatory and antioxidant effects, and apoptosis mitigation, make mesaconine a promising candidate for further exploration in AKI management.

Clinical-grade human skin-derived ABCB5+ mesenchymal stromal cells exert anti-apoptotic and anti-inflammatory effects in vitro and modulate mRNA expression in a cisplatin-induced kidney injury murine model.

Acute kidney injury (AKI) is characterized by a rapid reduction in renal function and glomerular filtration rate (GFR). The broadly used anti-cancer chemotherapeutic agent cisplatin often induces AKI as an adverse drug side effect. Therapies targeted at the reversal of AKI and its potential progression to chronic kidney disease or end-stage renal disease are currently insufficiently effective. Mesenchymal stromal cells (MSCs) possess diverse immunomodulatory properties that confer upon them significant therapeutic potential for the treatment of diverse inflammatory disorders. Human dermal MSCs expressing ATP-Binding Cassette member B5 (ABCB5) have shown therapeutic efficacy in clinical trials in chronic skin wounds or recessive dystrophic epidermolysis bullosa. In preclinical studies, ABCB5+ MSCs have also shown to reverse metabolic reprogramming in polycystic kidney cells, suggesting a capacity for this cell subset to improve also organ function in kidney diseases. Here, we aimed to explore the therapeutic capacity of ABCB5+ MSCs to improve renal function in a preclinical rat model of cisplatin-induced AKI. First, the anti-apoptotic and immunomodulatory capacity was compared against research-grade adipose stromal cells (ASCs). Then, cross-species immunomodulatory capacity was checked, testing first inhibition of mitogen-driven peripheral blood mononuclear cells and then modulation of macrophage function. Finally, therapeutic efficacy was evaluated in a cisplatin AKI model. First, ABCB5+ MSCs suppressed cisplatin-induced apoptosis of human conditionally-immortalized proximal tubular epithelial cells in vitro, most likely by reducing oxidative stress. Second, ABCB5+ MSCs inhibited the proliferation of either human or rat peripheral blood mononuclear cells, in the human system via the Indoleamine/kynurenine axis and in the murine context via nitric oxide/nitrite. Third, ABCB5+ MSCs decreased TNF-α secretion after lipopolysaccharide stimulation and modulated phagocytosis and in both human and rat macrophages, involving prostaglandin E2 and TGF-β1, respectively. Fourth, clinical-grade ABCB5+ MSCs grafted intravenously and intraperitoneally to a cisplatin-induced AKI murine model exerted modulatory effects on mRNA expression patterns toward an anti-inflammatory and pro-regenerative state despite an apparent lack of amelioration of renal damage at physiologic, metabolic, and histologic levels. Our results demonstrate anti-inflammatory and pro-regenerative effects of clinical grade ABCB5+ MSCs in vitro and in vivo and suggest potential therapeutic utility of this cell population for treatment or prevention of cisplatin chemotherapy-induced tissue toxicity.

N-Acetylcysteine Improves Renal Function and Reduces Tissue Malondialdehyde Levels in Glycerol-Induced Acute Kidney Injury

Introduction: The etiology of myoglobinuric acute kidney injury involves oxidative injury brought on by the Fenton reaction and myoglobin redox cycle. Renal tubules may be harmed, and lipid peroxidation compounds with vasoconstrictor characteristics may be produced. N-acetylcysteine (NAC) is an antioxidant shown to improve renal microcirculation and have protective effects in various models of renal damage. The aim of the study was to demonstrate the protective impact of NAC in glycerol-induced rats by measuring tissue malondialdehyde (MDA) level and renal function test (RFT), and to determine the correlation between the protective effect and NAC dose.Methods: This study measured tissue malondialdehyde (MDA) and renal function to examine any protective effect of NAC in a glycerol-induced rat model and to determine whether the effect was dose-related. Five groups of male Wistar rats were used: 1) saline control group, (2) glycerol (50%, 8mL/kg, i.m) plus saline i.v group, 3) glycerol plus NAC (100 mg/kg)-treated group, 4) glycerol plus NAC (200 mg/kg)-treated group, 5) glycerol plus NAC (400 mg/kg)-treated group. At 24 hrs, after glycerol injection, rats were sacrificed, cardiac blood was taken for renal function measurement, and renal tissues were removed for thiobarbituric acid MDA level assessment.Results: Our study revealed that glycerol administration significantly amplified renal tissue MDA, serum creatinine, and BUN (blood urea nitrogen) levels. However, NAC administration dampened the MDA increment and renal function deterioration (p<0.05). Moreover, tissue MDA, BUN, and serum creatinine levels were significantly correlated to NAC dose (r=0.485; r=0.491; rs=0.544, respectively; all p<0.05), indicating that NAC protection declines by dose increments.Conclusion: In this glycerol-induced acute kidney injury rat model, the administration of intravenous NAC 100 mg/kg reduced lipid peroxidation and improved renal function. Nevertheless, the protective effect was diminished in higher doses.

Polylactic acid nanoparticles loaded with losartan potassium regulate the expression of ET-1 in acute kidney injury

This study explored specific mechanism of action for polylactic acid-loaded nanoparticles loaded with losartan potassium to regulate the expression of ET-1 in acute kidney injury. Preparation and identification of Polylactic acid nanoparticles (PLA-NP) loaded with losartan potassium (PLA-NP-LP) were herein performed. After establishment of acute kidney injury rat models, the rats were assigned into model group, PLA-NP group, losartan potassium group, PLA-NP-LP group, NF-kB agonist group, NF-kB inhibitor group, NF-kB agonist and inhibitor group respectively. After one week of intervention, rat kidney tissues were taken for Hematoxylin and Eosin (H&E) staining and Real-time Polymerase Chain Reaction (PCR) and Western blot were used to measure the levels of NF-kB and ET-1, along with analysis of levels of creatinine and blood urea nitrogen by an automatic biochemical analyzer. PLA-NP-LP nanoparticles was successfully prepared with good shape. The levels of creatinine and urea nitrogen, renal tubular dilation and epithelial edema in the PLA-NP-LP group were lowest (vs. model group and losartan Potassium group), with P < 0.05. PLA-NP-LP inhibited the expression of ET-1 and NF-kB, P < 0.05. The ET-1 expression level for rats in the NF-kB agonist combined with PLA-NP-LP group was higher (vs. PLA-NP-LP group). Moreover, the level of ET-1 decreased (P < 0.05). PLA-NP-LP can improve renal function of rats with acute kidney injury, reduce renal tubular epithelial edema, and downregulate ET-1 in the rat kidney, by inhibiting the expression of NF-kB.

Soluble thrombomodulin alleviates Diquat-induced acute kidney injury by inhibiting the HMGB1/IκBα/NF-κB signalling pathway.

Our research aimed to investigate whether soluble thrombomodulin (sTM) relieved Diquat (DQ)-induced acute kidney injury (AKI) via HMGB1/IκBα/NF-κB signaling pathways. An AKI rat model was constructed using DQ. Pathological changes in renal tissue were detected by HE and Masson staining. Gene expression was determined using qRT-PCR, IHC, and western blotting. Cell activity and apoptosis were analysed using CCK-8 and Flow cytometry, respectively. An abnormal kidney structure was observed in DQ rats. The levels of blood urea nitrogen (BUN), creatinine (CRE), uric acid (UA), oxidative stress, and inflammatory responses in the DQ group increased on the 7th day but decreased on the 14th day, compared with the control group. Additionally, HMGB1, sTM, and NF-kappaB (NF-κB) expression had increased in the DQ group compared with the control group, while the IκKα and IκB-α levels had decreased. In addition, sTM relieved the damaging effects of diquat on renal tubular epithelial cell viability, apoptosis, and the inflammatory response. The levels of HMGB1, TM, and NF-κB mRNA and protein were significantly decreased in the DQ+sTM group compared with the DQ group. These findings indicated that sTM could relieve Diquat-induced AKI through HMGB1/IκBα/NF-κB signaling pathways, which provides a treatment strategy for Diquat-induced AKI.

Proteomics analyses of acute kidney injury biomarkers in a rat exertional heat stroke model.

The frequency of exertional heat stroke (EHS) increases with the gradual elevation of global temperatures during summer. Acute kidney injury (AKI) is a common complication of EHS, and its occurrence often indicates the worsening of a patient's condition or a poor prognosis. In this study, a rat model of AKI caused by EHS was established, and the reliability of the model was evaluated by HE staining and biochemical assays. The expression of kidney tissue proteins in the EHS rats was analyzed using label-free liquid chromatography-tandem mass spectrometry. A total of 3,129 differentially expressed proteins (DEPs) were obtained, and 10 key proteins were finally identified, which included three upregulated proteins (Ahsg, Bpgm, and Litaf) and seven downregulated proteins (medium-chain acyl-CoA synthetase 2 (Acsm2), Hadha, Keg1, Sh3glb1, Eif3d, Ambp, and Ddah2). The qPCR technique was used to validate these 10 potential biomarkers in rat kidney and urine. In addition, Acsm2 and Ahsg were double-validated by Western blotting. Overall, this study identified 10 reliable biomarkers that may provide potential targets for the treatment of AKI caused by EHS.

Alpha-Mangostin ameliorates acute kidney injury via modifying levels of circulating TNF-α and IL-6 in glycerol-induced rhabdomyolysis animal model.

Alpha mangostin (AM), isolated from G. mangostana, showed beneficial effects in several disorders due to its antioxidant and anti-inflammatory properties. Acute kidney injury (AKI) due to different etiologies can develop into severe complications, resulting in high mortality rates. In this work, AM is tested for its ability to alleviate AKI in glycerol-induced AKI rat model, where 30 Male Sprague-Dawley rats were assigned to a healthy group, glycerol-treated group and AM-treated group. Glycerol- and AM groups received a single dose of glycerol (per IM, 50% glycerol in saline, 8 ml/kg), whereas control group was injected with saline. AM treatment (a single daily dose, per IP, 175mg/kg) was accomplished for three days. Animals were executed to collect blood samples and kidney tissue for biochemical and histological examination. It was found that glycerol induced increase in serum creatinine, blood urea nitrogen (BUN), lipid peroxidation, serum magnesium, TNF-α and IL-6. It also induced renal edema and hypocalcemia along with histopathological renal damage. AM treatment improved renal histological features and alleviated increase in serum creatinine, BUN, serum magnesium, TNF-α and IL-6 levels, as well as renal edema and lipid peroxidation but did not affect serum calcium levels. This suggests AM as a potential therapeutic agent for treating AKI mainly via its antioxidant and anti-inflammatory properties.

Identification of AGXT2, SHMT1, and ACO2 as important biomarkers of acute kidney injury by WGCNA.

Acute kidney injury (AKI) is a serious and frequently observed disease associated with high morbidity and mortality. Weighted gene co-expression network analysis (WGCNA) is a research method that converts the relationship between tens of thousands of genes and phenotypes into the association between several gene sets and phenotypes. We screened potential target genes related to AKI through WGCNA to provide a reference for the diagnosis and treatment of AKI. Key biomolecules of AKI were investigated based on transcriptome analysis. RNA sequencing data from 39 kidney biopsy specimens of AKI patients and 9 normal subjects were downloaded from the GEO database. By WGCNA, the top 20% of mRNAs with the largest variance in the data matrix were used to construct a gene co-expression network with a p-value < 0.01 as a screening condition, showing that the blue module was most closely associated with AKI. Thirty-two candidate biomarker genes were screened according to the threshold values of |MM|≥0.86 and |GS|≥0.4, and PPI and enrichment analyses were performed. The top three genes with the most connected nodes, alanine-glyoxylate aminotransferase 2(AGXT2), serine hydroxymethyltransferase 1(SHMT1) and aconitase 2(ACO2), were selected as the central genes based on the PPI network. A rat AKI model was constructed, and the mRNA and protein expression levels of the central genes in the model and control groups were verified by PCR and immunohistochemistry experiments. The results showed that the relative mRNA expression and protein levels of AGXT2, SHMT1 and ACO2 showed a decrease in the model group. In conclusion, we inferred that there is a close association between AGXT2, SHMT1 and ACO2 genes and the development of AKI, and the down-regulation of their expression levels may induce AKI.

Human bone marrow mesenchymal stem cell-derived extracellular vesicles reduce inflammation and pyroptosis in acute kidney injury via miR-223-3p/HDAC2/SNRK.

Bone marrow mesenchymal stem cell (BMSC)-derived extracellular vesicles (EVs) have been demonstrated as a potential therapeutic agent in acute kidney injury (AKI). However, little is known about the mechanisms of action of BMSC-derived EVs in AKI. Based on this, our research was designed to investigate the mechanism behind BMSC-derived EVs controlling inflammation and pyroptosis during AKI. Peripheral blood from AKI patients was used for detection of microRNA (miR)-223-3p, HDAC2, and SNRK expression. An AKI rat model was established, and HK-2 cell injury was induced by lipopolysaccharide (LPS) to establish a cellular model. Co-culture with BMSC-derived EVs and/or gain- and loss-of-function assays were conducted in LPS-treated HK-2 to evaluate the functions of BMSCs-EVs, miR-223-3p, HDAC2, and SNRK. AKI rats were simultaneously injected with EVs and short hairpin RNAs targeting SNRK. The interactions among miR-223-3p, HDAC2, and SNRK were evaluated by RIP, ChIP, and dual-luciferase gene reporter assays. Patients with AKI had low miR-223-3p and SNRK expression and high HDAC2 expression in peripheral blood. Mechanistically, miR-223-3p targeted HDAC2 to accelerate SNRK transcription. In LPS-treated HK-2 cells, BMSCs-EVs overexpressing miR-223-3p increased cell viability and diminished cell apoptosis, KIM-1, LDH, IL-1β, IL-6, TNF-α, NLRP3, ASC, cleaved caspase-1, and IL-18 expression, and GSDMD cleavage, which was nullified by HDAC2 overexpression or SNRK silencing. In AKI rats, BMSCs-EV-shuttled miR-223-3p reduced CRE and BUN levels, apoptosis, inflammation, and pyroptosis, which was abrogated by SNRK silencing. Conclusively, BMSC-derived EV-encapsulated miR-223-3p mitigated AKI-induced inflammation and pyroptosis by targeting HDAC2 and promoting SNRK transcription.

1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic Acid Acetoxymethyl Ester Loaded Reactive Oxygen Species Responsive Hyaluronic Acid-Bilirubin Nanoparticles for Acute Kidney Injury Therapy via Alleviating Calcium Overload Mediated Endoplasmic Reticulum Stress.

Calcium overload is one of the early determinants of the core cellular events that contribute to the pathogenesis of acute kidney injury (AKI), which include oxidative stress, ATP depletion, calcium overload, and inflammatory response with self-amplifying and interactive feedback loops that ultimately lead to cellular injury and renal failure. Excluding adjuvant therapy, there are currently no approved pharmacotherapies for the treatment of AKI. Using an adipic dihydride linker, we modified the hyaluronic acid polymer chain with a potent antioxidant, bilirubin, to produce an amphiphilic conjugate. Subsequently, we developed a kidney-targeted and reactive oxygen species (ROS)-responsive drug delivery system based on the flash nanocomplexation method to deliver a well-known intracellular calcium chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester (BAPTA-AM, BA), with the goal of rescuing renal cell damage via rapidly scavenging of intracellularly overloaded Ca2+. In the ischemia-reperfusion (I/R) induced AKI rat model, a single dose of as-prepared formulation (BA 100 μg·kg-1) 6 h post-reperfusion significantly reduced renal function indicators by more than 60% within 12 h, significantly alleviated tissular pathological changes, ameliorated tissular oxidative damage, significantly inhibited apoptosis of renal tubular cells and the expression of renal tubular marker kidney injury molecule 1, etc., thus greatly reducing the risk of kidney failure. Mechanistically, the treatment with BA-loaded NPs significantly inhibited the activation of the ER stress cascade response (IRE1-TRAF2-JNK, ATF4-CHOP, and ATF6 axis) and regulated the downstream apoptosis-related pathway while also reducing the inflammatory response. The BA-loaded NPs hold great promise as a potential therapy for I/R injury-related diseases.

Assessment of Urinary Exosomal NHE3 as a Biomarker of Acute Kidney Injury.

The diagnosis of acute kidney injury (AKI) traditionally depends on the serum creatinine (Scr) and urine output, which lack sufficient sensitivity and specificity. Using urinary exosomes as a biomarker has unique advantages. To assess whether urinary exosomal Na+/H+ exchanger isoform 3 (NHE3) protein could serve as a biomarker of AKI, we constructed four AKI rat models: cisplatin (7.5 mg/kg) injected intraperitoneally (IP), furosemide (20 mg/kg, IP) with a low-NaCl (0.03%) diet, a low-NaCl (0.03%) diet with candesartan (1 mg/kg, IP) and bilateral ischemia and reperfusion (I/R) injury for 40 min. Additionally, we assessed six sepsis-associated AKI patients and six healthy volunteers. Urinary exosomes were extracted by ultracentrifugation, and the NHE3 protein abundance was tested by immunoblotting for all the AKI rats and human subjects. The isolated cup-shaped particles with an average diameter of 70 nm and enrichment in CD63 were identified as exosomes. NHE3 abundance was six times higher in exosomes than in the whole urine. In cisplatin-induced AKI rats, urinary exosomal NHE3 was increased on day 2, one day earlier than the increases in Scr and blood urea nitrogen (BUN). In additional rats, urinary exosomal NHE3 decreased along with the decline in Scr after EPO pretreatment. In volume-depletion AKI induced by furosemide injection with a low-NaCl diet, the urinary exosomal NHE3 expression was higher than that in the control. Under a low-NaCl diet with candesartan-related AKI, the urinary exosomal NHE3 was elevated on day 5, earlier than Scr. In I/R-injury AKI, the urinary exosomal NHE3 was also raised compared with that in the control. In humans, the urinary exosomal NHE3 level was also elevated in sepsis-associated AKI patients in comparison with that in the healthy volunteers. The urinary exosomal NHE3 was increased in multiple AKI; it may be used as a diagnostic biomarker of AKI.

Sufentanil promotes autophagy and improves ischemia-reperfusion-induced acute kidney injury via up-regulating microRNA-145.

Sufentanil has a good protective effect on myocardial and liver injury caused by ischemia reperfusion (IR), but its protective effect on kidney is still unclear. This study aims to investigate whether sufentanil can prevent IR-induced acute kidney injury (AKI) and to determine whether its efficacy is related to miR-145-mediated autophagy. A total of 40 rats were randomly divided into 5 groups (n=8 in each group): A sham group, an IR group, a sufentanil group, a sufentanil+miR-145 inhibitor control group (an anti-NC group) and a sufentanil+miR-145 inhibitor group (an anti-miR-145 group). Except for the sham group, the other groups established a rat AKI model induced by IR. The sufentanil group, the sufentanil+anti-NC group, and the sufentanil+anti-miR-145 were injected with sufentanil (1 μg/kg) through femoral vein 30 min before ischemia. The sufentanil+anti-NC group and the sufentanil+anti-miR-145 group were injected with miR-145 inhibitor control or anti-miR-145 (80 mg/kg) through the tail vein before sufentanil pretreatment. The structure and function of kidneys harvested from the rats were evaluated, and the protein levels of autophagy-related proteins, oxidative stress levels, and apoptosis levels were measured. Compared with the IR group, the renal structure and function were improved in the sufentanil group. The levels of blood urea nitrogen (BUN), creatinine (Cr), urinary kidney injury molecule 1 (KIM-1), neutrophil gelatinase related lipid transporter (NGAL), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6 and ROS were significantly decreased (all P<0.05). In addition, compared with the IR group, the levels of Beclin-1 and LC3 in renal tissues in the sufentanil group were significantly increased (both P<0.05), and the apoptosis in renal tissues was significantly reduced (P<0.05). Compared with the sufentanil+anti-NC group, the levels of BUN, Cr, KIM-1, NGAL, TNF-α, IL-1β, IL-6 and ROS in the sufentanil+anti-miR-145 group were significantly increased (all P<0.05), the levels of Beclin-1 and LC3 in renal tissues were significantly decreased (both P<0.05), and the apoptosis in renal tissues was significantly increased (P<0.05). Sufentanil can prevent the AKI induced by IR, which is related to the up-regulation of miR-145-mediated autophagy.

The Amomum tsao-ko Essential Oils Inhibited Inflammation and Apoptosis through p38/JNK MAPK Signaling Pathway and Alleviated Gentamicin-Induced Acute Kidney Injury

The clinical application of gentamicin may lead to acute kidney injury (AKI), and the nephrotoxicity of gentamicin is related to the pathological mechanism of several oxidative and inflammatory cytokines. Plant-derived essential oils have good anti-inflammatory and antioxidant properties. This study aimed to clarify the protective effect of Amomum tsao-ko essential oils (AOs) on gentamicin-induced AKI in rats and its possible mechanism. The rat AKI model was induced by intraperitoneal injection of gentamicin. After 14 days of oral AO treatment, the renal function and pathological changes of the kidney tissues were evaluated, and the level of kidney tissue oxidative stress was detected. The content of inflammatory cytokines was measured by ELISA. The expression of ERK1/2, JNK1/2, p38, NF-κB, caspase-3, and Bax/Bcl-2 proteins were estimated by Western blot analysis. The results showed that taking AO reduced the contents of serum urea and creatinine in AKI rats and improve the pathological changes and oxidative stress of the kidney tissue in rats. At the same time, AO reduced inflammation and apoptosis during AKI by regulating the MAPK pathway. The data show that AO has a protective effect on the kidneys and may be a potential drug for treating kidney injury.

Juniperus communis extract ameliorates lipopolysaccharide-induced acute kidney injury through the adenosine monophosphate-activated protein kinase pathway.

Septic shock can aggravate organ dysfunction and even lead to death. Juniperus communis (JCo) extract has been experimentally demonstrated to have anti‐inflammatory and antioxidant effects. We investigated the anti‐inflammatory and antioxidant mechanism of JCo extract in vivo and in vitro. In a lipopolysaccharide (LPS)‐induced acute kidney injury rat model, JCo extract improved animal survival, reduced kidney injury scores, suppressed kidney injury molecule‐1, and preserved E‐cadherin expression from LPS damage, as demonstrated by the immunohistochemistry examinations of the rat kidneys. In LPS‐stimulated NRK‐52E cells, JCo extract inhibited nuclear factor‐κB (NF‐κB) and increased adenosine monophosphate–activated protein kinase (AMPK) expression, prompting the activation of the antioxidant nuclear factor erythroid 2–related factor‐2/heme oxygenase‐1 pathway against oxidative stress. JCo extract ameliorated LPS‐induced acute kidney injury by suppressing NF‐κB signaling and stimulating the release of tumor necrosis factor‐α and interleukin‐1β through the AMPK pathway.

Head-to-head comparison of two SGLT-2 inhibitors on AKI outcomes in a rat ischemia-reperfusion model

The CREDENCE trial testing canagliflozin and the EMPA-REG OUTCOME trial testing empagliflozin suggest different effects on acute kidney injury (AKI). AKI diagnosis was mainly made based on changes of serum creatinine (sCr) although this also reflect mode of action of SGLT-2 inhibitors. We analyzed both compounds in a rat AKI model. The renal ischemia-reperfusion injury (I/R) model was used. Four groups were analyzed: sham, I/R+placebo, I/R+canagliflozin (30 mg/kg/day), I/R+ empagliflozin (10 mg/kg/day). Glucose excretion was comparable in both treatment groups indicating comparable SGLT-2 inhibition. Comparing GFR surrogate markers after I/R (sCr and blood urea nitrogen (BUN)), sCr peaked 24 h after I/R, BUN after 48 h, respectively, in the placebo treated I/R group. At all investigated time points after I/R sCr and BUN was higher in the I/R + canagliflozin group as compared to placebo treated rats, whereas the empagliflozin group did not differ from the placebo group. I/R led to tubular dilatation and necrosis. Empagliflozin was able to reduce that finding whereas canagliflozin had no effect. Treatment with empagliflozin also resulted in a significant reduction in an improved inflammatory score (p = 0.006). Renal expression of kidney injury molecule-1 (KIM-1) increased after I/R and empagliflozin but not canagliflozin significantly alleviated KIM-1 expression. I/R reduced urinary miR-26a excretion. Empagliflozin but not canagliflozin was able to restore normal levels of urinary miR-26a. This study in an AKI model confirmed safety data in the EMPA-REG OUTCOME trial suggesting that empagliflozin might reduce AKI risk. The empagliflozin effects on KIM-1 and miR-26a might indicate beneficial regulation of inflammation. These data should stimulate clinical studies with AKI risk as primary endpoint.