Neutrophil-independent mechanisms of caspase-1- and IL-18-mediated ischemic acute tubular necrosis in mice

Complete Genome Sequence and Probiotic Properties of Pediococcus acidilactici CLP03 Isolated from Healthy Felis catus

Probiotics are available from various sources, including the gastrointestinal tract of healthy animals. In this study, Pediococcus acidilactici was isolated for the first time from Felis catus and evaluated for its functionality. The findings revealed that P. acidilactici CLP03 exhibited inhibitory properties against pathogenic bacteria (E. coli, Salmonella, S. aureus, P. aeruginosa, and L. monocytogenes). Then, survival of strains exposed to pH 2.5, 0.3% bile salts, 0.5% bile salts, and gastrointestinal fluids was 63.97%, 98.84%, 87.95%, and 52.45%, respectively. Also, P. acidilactici CLP03 demonstrated high hydrophobicity (69.63-82.03%) and self-aggregation (73.51-81.44%), negative for hemolytic, and was susceptible to clindamycin. Finally, the scavenging rates of DPPH, ABTS, and O2- were 53.55%, 54.81%, and 85.13%, respectively, which demonstrated that the strain CLP03 has good oxidation resistance. All these characteristics contribute to the survival, colonization, and functionality of the strain in the gastrointestinal tract, indicating their excellent probiotic potential. On the other hand, animal experiments (KM mice, randomly assigned to four groups) showed that the gavage of CLP03 had no toxic effects on mice, increased the serum SOD content, and decreased the MDA and BUN contents, which revealed gavage of CLP03 significantly increased the antioxidant capacity of mice in vivo. In addition, complete genome annotation showed that P. acidilactici CLP03 had 1976 CDS genes, and the numbers of CRISPR, gene islands, and phages were 8, 3, and 6, respectively. In conclusion, P. acidilactici CLP03 could be a candidate functional cat probiotic to enhance animal health and welfare.

Overview of Antibiotic-Induced Nephrotoxicity

Drug-induced nephrotoxicity accounts for up to 60% of cases of acute kidney injury (AKI) in hospitalized patients and is associated with increased morbidity and mortality in both adults and children. Antibiotics are one of the most common causes of drug-induced nephrotoxicity. Mechanisms of antibiotic-induced nephrotoxicity include glomerular injury, tubular injury or dysfunction, distal tubular obstruction from casts, and acute interstitial nephritis (AIN) mediated by a type IV (delayed-type) hypersensitivity response. Clinical manifestations of antibiotic-induced nephrotoxicity include acute tubular necrosis (ATN), AIN, and Fanconi syndrome. Given the potential nephrotoxic effects of antibiotics on critically ill patients, the use of novel biomarkers can provide information to optimize dosing and duration of treatment and can help prevent nephrotoxicity when traditional markers, such as creatinine, are unreliable. Use of novel kidney specific biomarkers, such as cystatin C and urinary kidney injury molecule-1 (KIM-1), may result in earlier detection of AKI, dose adjustment, or discontinuation of antibiotic and development of nonnephrotoxic antibiotics.

Vagus nerve stimulation attenuates acute kidney injury induced by hepatic ischemia/reperfusion injury in rats

Hepatic ischemia/reperfusion (I/R) injury, caused by limited blood supply and subsequent blood supply, is a causative factor resulting in morbidity and mortality during liver transplantation and liver resection. Hepatic I/R injury frequently contributes to remote organ injury, such as kidney, lung, and heart. It has been demonstrated that vagus nerve stimulation (VNS) is effective in remote organ injury after I/R injury. Here, our aim is to investigate the potential action of VNS on hepatic I/R injury-induced acute kidney injury (AKI) and explore its underlying mechanisms. To test this hypothesis, male Sprague-Dawley rats were randomly assigned into three experimental groups: Sham group (sham operation, n = 6); I/R group (hepatic I/R with sham VNS, n = 6); and VNS group (hepatic I/R with VNS, n = 6). VNS was performed during the entire hepatic I/R process. Our results showed that throughout the hepatic I/R process, VNS significantly regulated the expression levels of various iconic factors and greatly enhanced the protein expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and hemeoxygenase-1 (HO-1) in the kidneys. These findings suggested that VNS may ameliorate hepatic I/R injury-induced AKI by suppressing inflammation, oxidative stress, and apoptosis probably through activating the Nrf2/HO-1 signaling pathway.

The value of urinary interleukin-18 in predicting acute kidney injury: a systematic review and meta-analysis

Aims

The aim of this study was to systematically review relevant studies to evaluate the value of urinary interleukin-18 (uIL-18) in predicting acute kidney injury (AKI).

Methods

A comprehensive search of PubMed, Medline, Embase, and Cochrane Library was conducted for literature published up to 1 August 2022. Quality Assessment Tool for Diagnostic Accuracy Studies-2 (QUADAS-2) was applied to assess the literature quality. Then, relevant data were extracted from each eligible study and a random-effects regression model was utilized to pool sensitivity, specificity, and construct summary receiver operating characteristic (SROC) and area under curve (AUC).

Results

Twenty-six studies with 7183 patients were enrolled and relevant information was extracted. The estimated sensitivity and specificity of uIL-18 in the diagnosis of AKI were 0.64 (95% confidence interval (CI): 0.54–0.73) and 0.77 (95%CI: 0.71–0.83), respectively. The pooled diagnostic odds ratio (DOR) was 6.08 (95%CI: 3.63–10.18), and the AUC of uIL-18 in predicting AKI was 0.78 (95%CI: 0.74–0.81). Subgroup analysis showed that uIL-18 in pediatric patients was more effective in predicting AKI than in adults (DOR: 7.33 versus 5.75; AUC: 0.81 versus 0.77).

Conclusions

Urinary IL-18 could be a relatively good biomarker with moderate predictive value for AKI, especially in pediatric patients. However, further research and clinical settings are still needed to validate our findings.

Vagus Nerve Stimulation Attenuates Acute Kidney Injury Induced by Hepatic Ischemia/Reperfusion Injury by Suppressing Inflammation, Oxidative Stress, and Apoptosis in Rats.. [DOI: 10.21203/rs.3.rs-1937916/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Hepatic ischemia reperfusion (I/R) injury, caused by limited blood supply and subsequent blood supply, is a causative factor resulting in morbidity and mortality during liver transplantation (LT) and liver resection. Hepatic I/R injury frequently contributes to remote organ injury, such as kidney, lung, and heart. It has been demonstrated that vagus nerve stimulation (VNS) is effective in remote organ injury after ischemia reperfusion injury. Here, our aim is to investigate the potential action of VNS on hepatic I/R injury-induced acute kidney injury (AKI) and explore its underlying mechanisms. To test this hypothesis, male Sprague-Dawley rats were randomly assigned into three experimental groups: Sham group (sham operation, n=6); I/R group (hepatic I/R with sham VNS, n=6); and VNS group (hepatic I/R with VNS, n=6). VNS was performed during the entire hepatic I/R process. Our results showed that throughout the hepatic I/R process, VNS significantly reduced inflammation, oxidative stress, and apoptosis, and greatly enhanced the protein expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and hemeoxygenase-1 (HO-1) in the kidneys. These findings suggest that VNS may ameliorate hepatic I/R injury-induced AKI by suppressing inflammation, oxidative stress, and apoptosis probably through activating the Nrf2/HO-1 signaling pathway.

Circulating LIGHT (TNFSF14) and Interleukin-18 Levels in Sepsis-Induced Multi-Organ Injuries

The novel therapeutic target cytokine LIGHT (TNFSF14) was recently shown to play a major role in COVID-19-induced acute respiratory distress syndrome (ARDS). This study aims to investigate the associations of plasma LIGHT and another potentially targetable cytokine, interleukin-18 (IL-18), with ARDS, acute hypoxic respiratory failure (AHRF), or acute kidney injury (AKI), caused by non-COVID-19 viral or bacterial sepsis. A total of 280 subjects diagnosed with sepsis, including 91 cases with sepsis triggered by viral infections, were investigated in this cohort study. Day 0 plasma LIGHT and IL-18, as well as 59 other biomarkers (cytokines, chemokines, and acute-phase reactants) were measured by sensitive bead immunoassay and associated with symptom severity. We observed significantly increased LIGHT level in both bacterial sepsis patients (p = 1.80 × 10⁻⁵) and patients with sepsis from viral infections (p = 1.78 × 10⁻³). In bacterial sepsis, increased LIGHT level was associated with ARDS, AKI, and higher Apache III scores, findings also supported by correlations of LIGHT with other biomarkers of organ failure. IL-18 levels were highly variable across individuals and consistently correlated with Apache III scores, mortality, and AKI in both bacterial and viral sepsis. There was no correlation between LIGHT and IL-18. For the first time, we demonstrate independent effects of LIGHT and IL-18 in septic organ failure. The association of plasma LIGHT with AHRF suggests that targeting the pathway warrants exploration, and ongoing trials may soon elucidate whether this is beneficial. Given the large variance of plasma IL-18 among septic subjects, targeting this pathway requires precise application.

Calorie Restriction Protects against Contrast-Induced Nephropathy via SIRT1/GPX4 Activation

Calorie restriction (CR) extends lifespan and increases resistance to multiple forms of stress, including renal ischemia-reperfusion (I/R) injury. However, whether CR has protective effects on contrast-induced nephropathy (CIN) remains to be determined. In this study, we evaluated the therapeutic effects of CR on CIN and investigated the potential mechanisms. CIN was induced by the intravenous injection of iodinated contrast medium (CM) iopromide (1.8 g/kg) into Sprague Dawley rats with normal food intake or 40% reduced food intake, 4 weeks prior to iopromide administration. We found that CR was protective of CIN, assessed by renal structure and function. CM increased apoptosis, reactive oxygen species (ROS), and inflammation in the renal outer medulla, which were decreased by CR. The silent information regulator 1 (SIRT1) participated in the protective effect of CR on CIN, by upregulating glutathione peroxidase 4 (GPX4), a regulator of ferroptosis, because this protective effect was reversed by EX527, a specific SIRT1 antagonist. Our study showed that CR protected CIN via SIRT1/GPX4 activation. CR may be used to mitigate CIN.

hnRNPK knockdown alleviates NLRP3 inflammasome priming by repressing FLIP expression in Raw264.7 macrophages

Objectives: Inflammation is an important predisposing and progressive factor in chronic kidney disease (CKD). Heterogeneous nuclear ribonucleoprotein K (hnRNPK) is associated with many fundamental cellular processes, but in chronic inflammatory pathologies remains unclear.

Methods: An in vitro peripheral inflammation model was established using lipopolysaccharide (LPS)-stimulated mouse RAW264.7 macrophages, followed by inflammasome activation by ATP treatment. Knockdown of hnRNPK by sihnRNPK and FLICE-like inhibitory protein (FLIP) by siFLIP transfection were achieved in Raw264.7 macrophages. ELISA was used to determine the expression of IL-1β, IL-18 and TNF-α. Real time PCR was applied to detect the mRNA levels of hnRNPK, NOD-like receptors family pyrin domain-containing 3 (NLRP3), FLIP, Caspase-1, IL-1β and IL-18. Western blot and immunofluorescence were performed to detect relevant protein expressions. Co-immunoprecipitation (Co-IP) was used to assess the interaction of hnRNPK with FLIP.

Results: Results showed that LPS plus ATP activated NLRP3 inflammasome, which evidenced by the up-regulation of TNF-α, IL-1β and IL-18. Notably, hnRNPK and FLIP were significantly up-regulated in activated NLRP3 inflammasome of macrophages. HnRNPK or FLIP knockdown significantly suppressed the activation of NLRP3 inflammasome, as reflected by down-regulation of Caspase-1, IL-1β and IL-18. Importantly, hnRNPK could directly bind to FLIP in activated NLRP3 inflammasome.

Discussion: Our findings suggest that hnRNPK could promote the activation of NLRP3 inflammasome by directly binding FLIP, which might provide potential new therapeutic targets for CKD.

Chess Not Checkers: Complexities Within the Myeloid Response to the Acute Kidney Injury Syndrome

Immune dysregulation in acute kidney injury (AKI) is an area of intense interest which promises to enhance our understanding of the disease and how to manage it. Macrophages are a heterogeneous and dynamic population of immune cells that carry out multiple functions in tissue, ranging from maintenance to inflammation. As key sentinels of their environment and the major immune population in the uninjured kidney, macrophages are poised to play an important role in the establishment and pathogenesis of AKI. These cells have a profound capacity to orchestrate downstream immune responses and likely participate in skewing the kidney environment toward either pathogenic inflammation or injury resolution. A clear understanding of macrophage and myeloid cell dynamics in the development of AKI will provide valuable insight into disease pathogenesis and options for intervention. This review considers evidence in the literature that speaks to the role and regulation of macrophages and myeloid cells in AKI. We also highlight barriers or knowledge gaps that need to be addressed as the field advances.

CB1 receptor antagonist rimonabant protects against chronic intermittent hypoxia-induced renal injury in rats

BACKGROUND

Obstructive sleep apnoea (OSA) induced chronic kidney disease is mainly caused by chronic intermittent hypoxia (CIH). Our study investigate the mechanism underlying CIH-induced renal damage and whether the cannabinoid receptor 1 (CB1R) antagonist rimonabant (Ri) alleviates CIH-induced renal injury.

METHODS

Male Sprague-Dawley rats were randomly divided into five groups: one normal control (NC) group, two chronic intermittent hypoxia (CIH) groups, and two CIH + Ri groups. Rats in the NC groups were exposed to room air, while the CIH groups were exposed to a CIH environment for 4 weeks (4w CIH group) and 6 weeks (6w CIH group), respectively. Additionally, rats in the CIH + Ri groups were administered 1.5 mg/kg/day Ri for 4 weeks (4w CIH + Ri group) and 6 weeks (6w CIH + Ri group), respectively. Following this, the rats were euthanized and kidneys were excised for downstream analysis. In the renal tissues, the morphological alterations were examined via haematoxylin eosin (HE) staining and periodic acid schiff (PAS) staining, CB1R, Fis1, Mfn1, and p66Shc expression was assessed through western blot and immunohistochemistry, and the mitochondrial ultrastructural changes in kidney sections were assessed by electron microscopy.

RESULTS

CB1R expression in the 4w and 6w CIH groups was significantly elevated, and further increased with prolonged hypoxia; however, Ri prevented the increase in CIH-induced CB1R expression. Fis1 and p66Shc expression in the CIH groups were increased, but Mfn1 expression decreased. Ri decreased Fis1 and p66Shc expression and increased Mfn1 expression. Renal damage in the 4w or 6w CIH + Ri group was evidently improved compared with that in the 4w or 6w CIH group. CB1R expression was positively correlated with Fis1 and p66Shc and negatively correlated with Mfn1. Meanwhile, electron microscopy showed that the percentage of fragmented mitochondria in the tubular cells in each group was consistent with the trend of CB1R expression.

CONCLUSION

CIH causes endocannabinoid disorders and induces abnormal mitochondrial dynamics, resulting in renal injury. Treatment with CB1R antagonists reduces CIH-induced renal damage by inhibiting dysregulated renal mitochondrial dynamics.

The Role of Endothelins, IL-18, and NGAL in Kidney Hypothermic Machine Perfusion

Ischemia-reperfusion injury (IRI) occurring after renal transplantation is a complex biochemical process that can be monitored by specific biomarkers. The roles of those are not yet fully elucidated. The aim of this study was to analyze the concentrations of endothelins (ET-1, ET-2, and ET-3), interleukin-18 (IL-18), and neutrophil gelatinase-associated lipocalin (NGAL) during the reperfusion of human kidneys grafted from brain dead donors and later transplanted. The study group (n = 44) was analyzed according to the method of kidney storage: Group 1 underwent hypothermic machine perfusion (HMP) in the LifePort perfusion pump (n = 22), and Group 2 underwent static cold storage (SCS) (n = 22). The analysis of kidney function was performed daily during the first seven days after transplantation. The kidneys in Group 1 were characterized by higher absolute concentrations of ET-1, IL-18, and NGAL, as well as a lower concentration of ET-2 (p = 0.017) and ET-3. The relative increase of ET-1 (p = 0.033), ET-2, and ET-3 during reperfusion was lower in this group, while the relative decrease of NGAL was higher. Group 1 was also characterized by significant decrease of IL-18 (p = 0.026) and a tendency for better kidney function based on the higher total diuresis, higher glomerular filtration rate (GFR), higher potassium level, lower serum creatinine, and lower urea concentration during the seven-day postoperative observation period. The long-term beneficial impact of hypothermic machine perfusion on the outcome of transplanted kidneys may rely on the early modified proceedings and intensity of ischemia-reperfusion injury reflected by the dynamics of the concentrations of examined biomarkers.

The combination of G-CSF and AMD3100 mobilizes bone marrow-derived stem cells to protect against cisplatin-induced acute kidney injury in mice

BACKGROUND

Several studies have confirmed that mobilizing bone marrow-derived stem cells (BMSCs) ameliorates renal function loss following cisplatin-induced acute kidney injury (AKI). The aim of this study was to explore whether the combination of granulocyte-colony stimulating factor (G-CSF) and plerixafor (AMD3100) exerts beneficial effects on renal function recovery in a model of cisplatin-induced nephrotoxicity.

METHODS

C57BL/6J mice received intraperitoneal injections of G-CSF (200 μg/kg/day) for 5 consecutive days. On the day of the last injection, the mice received a single subcutaneous dose of AMD3100 (5 mg/kg) 1 h before cisplatin 20 mg/kg injection. Ninety-six hours after cisplatin injection, the mice were euthanized, and blood and tissue samples were collected to assess renal function and tissue damage. Cell mobilization was assessed by flow cytometry (FCM).

RESULTS

Mice pretreated with G-CSF/AMD3100 exhibited longer survival and lower serum creatinine and blood urea nitrogen (BUN) levels than mice treated with only G-CSF or saline. Combinatorial G-CSF/AMD3100 treatment attenuated tissue injury and cell death, enhanced cell regeneration, and mobilized a higher number of stem cells in the peripheral blood than G-CSF or saline treatment. Furthermore, the mRNA expression of proinflammatory factors was lower, whereas that of anti-inflammatory factors was higher, in the G-CSF/AMD3100 group than in the G-CSF or saline group (all P < 0.05).

CONCLUSIONS

These results suggest that combinatorial G-CSF/AMD3100 therapy mobilizes BMSCs to accelerate improvements in renal functions and prevent cisplatin-induced renal tubular injury. This combinatorial therapy may represent a new therapeutic option for the treatment of AKI and should be further investigated in the future.

A pilot study evaluating GSK1070806 inhibition of interleukin-18 in renal transplant delayed graft function

INTRODUCTION

Delayed graft function (DGF) following renal transplantation is a manifestation of acute kidney injury (AKI) leading to poor long-term outcome. Current treatments have limited effectiveness in preventing DGF. Interleukin-18 (IL18), a biomarker of AKI, induces interferon-γ expression and immune activation. GSK1070806, an anti-IL18 monoclonal antibody, neutralizes activated (mature) IL18 released from damaged cells following inflammasome activation. This phase IIa, single-arm trial assessed the effect of a single dose of GSK1070806 on DGF occurrence post donation after circulatory death (DCD) kidney transplantation.

METHODS

The 3 mg/kg intravenous dose was selected based on prior studies and physiologically based pharmacokinetic (PBPK) modeling, indicating the high likelihood of a rapid and high level of IL18 target engagement when administered prior to kidney allograft reperfusion. Utilization of a Bayesian sequential design with a background standard-of-care DGF rate of 50% based on literature, and confirmed via extensive registry data analyses, enabled a statistical efficacy assessment with a minimal sample size. The primary endpoint was DGF frequency, defined as dialysis requirement ≤7 days post transplantation (except for hyperkalemia). Secondary endpoints included safety, pharmacokinetics and pharmacodynamic biomarkers.

RESULTS

GSK1070806 administration was associated with IL18-GSK1070806 complex detection and increased total serum IL18 levels due to IL18 half-life prolongation induced by GSK1070806 binding. Interferon-γ-induced chemokine levels declined or remained unchanged in most patients. Although the study was concluded prior to the Bayesian-defined stopping point, 4/7 enrolled patients (57%) had DGF, exceeding the 50% standard-of-care rate, and an additional two patients, although not reaching the protocol-defined DGF definition, demonstrated poor graft function. Six of seven patients experienced serious adverse events (SAEs), including two treatment-related SAEs.

CONCLUSION

Overall, using a Bayesian design and extensive PBPK dose modeling with only a small sample size, it was deemed unlikely that GSK1070806 would be efficacious in preventing DGF in the enrolled DCD transplant population.

TRIAL REGISTRATION

NCT02723786.

Comparative study of gavage and intraperitoneal administration of gamma-oryzanol in alleviation/attenuation in a rat animal model of renal ischemia/reperfusion-induced injury

OBJECTIVES

Ischemia/reperfusion (I/R) is the leading cause of acute kidney injury. This study aimed to elucidate the reno-protective effect of gamma-oryzanol (GO) by comparing gavage and intraperitoneal (IP) administration methods on renal I/R injury in a rat model.

MATERIALS AND METHODS

Rats were divided into four groups including (group 1) sham, (group 2) I/R-control, (group 3) I/R+GO gavage-treated, and (group 4) I/R+ GO IP-treated. A single dose of GO was administrated to groups 3 and 4 (100 mg/kg body weight), 60 min before induction of I/R. After anesthesia, I/R was created by 45 min of ischemia, followed by 6 hr of reperfusion. Then, blood and tissue samples were subjected to evaluation of renal function, anti-oxidant capacity, inflammation, apoptotic proteins, and IKB/NF-kB pathway.

RESULTS

The two GO administration methods showed improvement of renal function along with attenuation of histological abnormalities. An increase in antioxidant capacity along with a decrease in pro-inflammatory markers, decline in the expression levels of BAX, Bax/Bcl-2, and caspase-3, and up-regulation of Bcl-2 expression were recorded. Moreover, a significant decrease in NF-Kb, p-IKBα, and MMP-2/9 with an increase in IKBα levels were also observed. Overall, in a comparative evaluation between the two gavage and IP administration methods, we did not find any differences in all examined parameters, except IL-6 which had a better result via gavage.

CONCLUSION

A single dose of GO administration has a reno-protective effect against renal I/R injury. Gavage and IP administration exhibit similar efficiency in alleviation of I/R injury.

An In-vivo Study into the Effects of Schisandrin B in the Liver, Spleen, Kidney, and Brain of Acute Thioacetamide-intoxicated Mice

Currently, there are no effective treatments for liver diseases. Treatment usually involves controlling complications and supportive care. As liver injuries also affect other organs such as the spleen, kidney, and brain due to their anatomical and physiological relationships, finding an effective treatment is urgently needed. This research aimed to evaluate the therapeutic effect of Schisandrin B (Sch B) in the liver and other organs in thioacetamide (TAA)-intoxicated mice. In this study, mice were exposed to a single intraperitoneal injection of 200 mg/kg TAA to induce hepatitis. Following Sch B (20 mg/kg/day, 28 consecutive days) treatment, biochemistry analysis and histopathological examination of different organs were performed, in addition to western blotting and flow cytometry to evaluate the involvement of inflammasomes and apoptotic proteins. Our results showed that administration of Sch B protected against TAA-induced damages, and it disparately affected inflammasome activation and apoptosis in different organs. Furthermore, Sch B treatment improved organ function, as indicated by the improvement of serum biochemical parameters. Collectively, our findings reveal a beneficial effect of Sch B on different organ damages in mice intoxicated with TAA.

Gm614 Protects Germinal Center B Cells From Death by Suppressing Caspase-1 Transcription in Lupus-Prone Mice

Only a few signaling pathways have been reported in germinal center (GC) B-cell proliferation and death. In this study, we showed that a novel uncharacterized Gm614 protein is highly expressed in GC B cells from lupus-prone mice. Critically, ablation of this GC B-cell-specific Gm614 promoted GC B-cell death and mitigation of autoimmune symptoms, whereas overexpression protected GC B cells from death and exacerbated autoimmune symptoms. We demonstrated that mechanistically, nuclear-localized Gm614 reduced caspase-1 expression in GC B cells by binding with caspase-1 promoter to suppress its activation. Our results suggest that Gm614 protects GC B cells from death by suppressing caspase-1 transcription in autoimmune diseases. This may provide some hints for targeting the cell proliferation involved in autoimmune diseases.

Investigation of the Effects and Mechanisms of Dendrobium loddigesii Rolfe Extract on the Treatment of Gout

Objective

Gout is a chronic disease that causes inflammatory arthritis, which is closely related to urate accumulation induced by a disorder of uric acid metabolism and the consequent deposition of monosodium urate crystals. Dendrobium loddigesii Rolfe is an herbal medicine that has been used in some traditional Chinese medicine formulae in the treatment of gout. This study aimed to explore and verify the antigout activity of Dendrobium loddigesii extract (DLE) on alleviating the hyperuricaemia of mice and the acute gouty arthritis of rats.

Methods

An animal model of hyperuricaemia was established using potassium oxonate (PO). We analysed the expression of uric acid transporter mRNA in the kidney in the hyperuricaemic mice after treatment with DLE. Simultaneously, a monosodium urate crystal-induced acute gouty arthritis rat model was used to evaluate the effects of DLE, according to the level of ankle swelling, as well as the protein levels of inflammatory receptors and cytokines, as assayed by WB and ELISA.

Results

DLE alleviated hyperuricaemia in mice and inhibited acute gouty arthritis in rats (P < 0.05). Meanwhile, DLE regulated the levels of uric acid transporters mRNA transcripts, including mouse organic anion transporter 1 (mOAT1), organic anion transporter 3 (mOAT3), urate transporter 1 (mURAT1), and glucose transporter 9 (mGLUT9) in the kidney (P < 0.05), suggesting that DLE promoted uric acid metabolism. Furthermore, DLE significantly suppressed the protein levels of TLRs, MyD88, and NF-κB in the ankle joint's synovium (P < 0.05), and the serum levels of IL-1β, IL-6, and TNF-α were also reduced, which demonstrated the anti-inflammatory effects of DLE.

Conclusion

DLE alleviates hyperuricaemia by regulating the transcription level of uric acid transporters in the kidney. It also inhibits acute gouty arthritis by inhibiting the pathway of TLRs/MyD88/NF-κB in the ankle joint's synovium. The findings of the present study imply that DLE alleviates gout by promoting uric acid metabolism and inhibiting inflammation related to the TLRs/MyD88/NF-κB pathway.

Assessing the health of the nephron in acute kidney injury: biomarkers of kidney function and injury

PURPOSE OF REVIEW

Serum creatinine and urine output continue to be the mainstays of diagnosis of acute kidney injury, though both of these measures have significant limitations, especially in acutely hospitalized patients. Biomarkers in both blood and urine have been studied extensively in the research setting and are on the verge of clinical practice to improve diagnosis of AKI.

RECENT FINDINGS

Blood and urine biomarkers can be localized to specific areas or functions within the nephron. Biomarkers can help to characterize glomerular or tubular function; glomerular, tubular, or interstitial injury; inflammation; or repair. Further, biomarkers can improve diagnosis of AKI in various clinical settings including acute interstitial nephritis, acute tubular injury, and hepatorenal syndrome, and cardiorenal syndrome.

SUMMARY

Biomarkers are becoming more prevalent in both research and getting close to clinical use. Both blood and urine biomarkers can help to localize impairment in nephron health by either location or function within the nephron and among various causes of AKI.

Kinin B1 receptor: a potential therapeutic target in sepsis-induced vascular hyperpermeability

Background

In sepsis, the endothelial barrier becomes incompetent, with the leaking of plasma into interstitial tissues. VE-cadherin, an adherens junction protein, is the gatekeeper of endothelial cohesion. Kinins, released during sepsis, induce vascular leakage and vasodilation. They act via two G-protein coupled receptors: B1 (B1R) and B2 (B2R). B1R is inducible in the presence of pro-inflammatory cytokines, endotoxins or after tissue injury. It acts at a later stage of sepsis and elicits a sustained inflammatory response. The aim of our study was to investigate the relationships between B1R and VE-cadherin destabilization in vivo in a later phase of sepsis.

Methods

Experimental, prospective study in a university research laboratory. We used a polymicrobial model of septic shock by cecal ligation and puncture in C57BL6 male mice or C57BL6 male mice that received a specific B1R antagonist (R-954). We studied the influence of B1R on sepsis-induced vascular permeability 30 h after surgery for several organs, and VE-cadherin expression in the lung and kidneys by injecting R-954 just before surgery. The 96-h survival was determined in mice without treatment or in animals receiving R-954 as a “prophylactic” regimen (a subcutaneous injection of 200 µg/kg, prior to CLP and 24 h after CLP), or as a “curative” regimen (injection of 100 µg/kg at H6, H24 and H48 post-surgery).

Results

B1R inactivation helps to maintain MAP above 65 mmHg but induces different permeability profiles depending on whether or not organ perfusion is autoregulated. In our model, VE-cadherin was destabilized in vivo during septic shock. At a late stage of sepsis, the B1R blockade reduced the VE-cadherin disruption by limiting eNOS activation. The survival rate for mice that received R-954 after sepsis induction was higher than in animals that received an antagonist as a prophylactic treatment.

Conclusions

B1R antagonizing reduced mortality in our model of murine septic shock by limiting the vascular permeability induced by VE-cadherin destabilization through maintenance of the macrohemodynamics, consequently limiting organ dysfunctions.

"Point of no return" in unilateral renal ischemia reperfusion injury in mice

Background

In the past years evidence has been growing about the interconnection of chronic kidney disease and acute kidney injury. The underlying pathophysiological mechanisms remain unclear. We hypothesized, that a threshold ischemia time in unilateral ischemia/reperfusion injury sets an extent of ischemic tubule necrosis, which as “point of no return” leads to progressive injury. This progress is temporarily associated by increased markers of inflammation and results in fibrosis and atrophy of the ischemic kidney.

Methods

Acute tubule necrosis was induced by unilateral ischemia/reperfusion injury in male C57BL/6 N mice with different ischemia times (15, 25, 35, and 45 min). At multiple time points between 15 min and 5 weeks we assessed gene expression of markers for injury, inflammation, and fibrosis, histologically the injury of tubules, cell death (TUNEL), macrophages, neutrophil influx and kidney atrophy.

Results

Unilateral ischemia for 15 and 25 min induced upregulation of markers for injury after reperfusion for 24 h but no upregulation after 5 weeks. None of the markers for inflammation or fibrosis were upregulated after ischemia for 15 and 25 min at 24 h or 5 weeks on a gene expression level, except for Il-6. Ischemia for 35 and 45 min consistently induced upregulation of markers for inflammation, injury, and partially of fibrosis (Tgf-β1 and Col1a1) at 24 h and 5 weeks. The threshold ischemia time for persistent injury of 35 min induced a temporal association of markers for inflammation and injury with peaks between 6 h and 7 d along the course of 10 d. This ischemia time also induced persistent cell death (TUNEL) throughout observation for 5 weeks with a peak at 6 h and progressing kidney atrophy beginning 7 d after ischemia.

Conclusions

This study confirms the evidence of a threshold extent of ischemic injury in which markers of injury, inflammation and fibrosis do not decline to baseline but remain upregulated assessed in long term outcome (5 weeks). Excess of this threshold as “point of no return” leads to persistent cell death and progressing atrophy and is characterized by a temporal association of markers for inflammation and injury.

Time-dependent effects of histone deacetylase inhibition in sepsis-associated acute kidney injury

BACKGROUND

Sepsis, a dysregulated host response to infection with results in organ dysfunction, has been a major challenge to the development of effective therapeutics. Sepsis-associated acute kidney injury (S-AKI) results in a 3-5-fold increase in the risk of hospital mortality compared to sepsis alone. The development of therapies to reverse S-AKI could therefore significantly affect sepsis outcomes. However, the translation of therapies from preclinical studies into humans requires model systems that recapitulate clinical scenarios and the development of renal fibrosis indicative of the transition from acute to chronic kidney disease.

RESULTS

Here we characterized a murine model of S-AKI induced by abdominal sepsis developing into a chronic phenotype. We applied a small molecule histone deacetylase-8 inhibitor, UPHD186, and found that early treatment, beginning at 48 h post-sepsis, worsened renal outcome accompanied by decreasing mononuclear cell infiltration in the kidney, skewing cells into a pro-inflammatory phenotype, and increased pro-fibrotic gene expression, while delayed treatment, beginning at 96 h post-sepsis, after the acute inflammation in the kidney had subsided, resulted in improved survival and kidney histology presumably through promoting proliferation and inhibiting fibrosis.

CONCLUSIONS

These findings not only present a clinically relevant S-AKI model, but also introduce a timing dimension into S-AKI therapeutic interventions that delayed treatment with UPHD186 may enhance renal histologic repair. Our results provide novel insights into successful repair of kidney injury and sepsis therapy.

Inflammatory Targets in Diabetic Nephropathy

One of the most frequent complications in patients with diabetes mellitus is diabetic nephropathy (DN). At present, it constitutes the first cause of end stage renal disease, and the main cause of cardiovascular morbidity and mortality in these patients. Therefore, it is clear that new strategies are required to delay the development and the progression of this pathology. This new approach should look beyond the control of traditional risk factors such as hyperglycemia and hypertension. Currently, inflammation has been recognized as one of the underlying processes involved in the development and progression of kidney disease in the diabetic population. Understanding the cascade of signals and mechanisms that trigger this maladaptive immune response, which eventually leads to the development of DN, is crucial. This knowledge will allow the identification of new targets and facilitate the design of innovative therapeutic strategies. In this review, we focus on the pathogenesis of proinflammatory molecules and mechanisms related to the development and progression of DN, and discuss the potential utility of new strategies based on agents that target inflammation.

Apoptosis and autophagy in polycystic kidney disease (PKD)

Apoptosis in the cystic epithelium is observed in most rodent models of polycystic kidney disease (PKD) and in human autosomal dominant PKD (ADPKD). Apoptosis inhibition decreases cyst growth, whereas induction of apoptosis in the kidney of Bcl-2 deficient mice increases proliferation of the tubular epithelium and subsequent cyst formation. However, alternative evidence indicates that both induction of apoptosis as well as increased overall rates of apoptosis are associated with decreased cyst growth. Autophagic flux is suppressed in cell, zebra fish and mouse models of PKD and suppressed autophagy is known to be associated with increased apoptosis. There may be a link between apoptosis and autophagy in PKD. The mammalian target of rapamycin (mTOR), B-cell lymphoma 2 (Bcl-2) and caspase pathways that are known to be dysregulated in PKD, are also known to regulate both autophagy and apoptosis. Induction of autophagy in cell and zebrafish models of PKD results in suppression of apoptosis and reduced cyst growth supporting the hypothesis autophagy induction may have a therapeutic role in decreasing cyst growth, perhaps by decreasing apoptosis and proliferation in PKD. Future research is needed to evaluate the effects of direct autophagy inducers on apoptosis in rodent PKD models, as well as the cause and effect relationship between autophagy, apoptosis and cyst growth in PKD.

Dendritic Cells as Sensors, Mediators, and Regulators of Ischemic Injury

Dendritic cells (DCs) are highly specialized, bone marrow (BM)-derived antigen-processing and -presenting cells crucial to the induction, integration and regulation of innate, and adaptive immunity. They are stimulated by damage-associated molecular patterns (DAMPS) via pattern recognition receptors to promote inflammation and initiate immune responses. In addition to residing within the parenchyma of all organs as part of the heterogeneous mononuclear phagocyte system, DCs are an abundant component of the inflammatory cell infiltrate that appears in response to ischemia reperfusion injury (IRI). They can play disparate roles in the pathogenesis of IRI since their selective depletion has been found to be protective, deleterious, or of no benefit in mouse models of IRI. In addition, administration of DC generated and manipulated ex vivo can protect organs from IRI by suppressing inflammatory cytokine production, limiting the capacity of DCs to activate NKT cells, or enhancing regulatory T cell function. Few studies however have investigated specific signal transduction mechanisms underlying DC function and how these affect IRI. Here, we address current knowledge of the role of DCs in regulation of IRI, current gaps in understanding and prospects for innovative therapeutic intervention at the biological and pharmacological levels.

CPUY192018, a potent inhibitor of the Keap1-Nrf2 protein-protein interaction, alleviates renal inflammation in mice by restricting oxidative stress and NF-κB activation

The Keap1-Nrf2-ARE pathway regulates the constitutive and inducible transcription of various genes that encode detoxification enzymes, antioxidant proteins and anti-inflammatory proteins and has pivotal roles in the defence against cellular oxidative stress. In this study, we investigated the therapeutic potential of CPUY192018, a potent small-molecule inhibitor of the Keap1-Nrf2 protein-protein interaction (PPI), in renal inflammation. In human proximal tubular epithelial HK-2 cells, CPUY192018 treatment significantly increased Nrf2 protein level and Nrf2 nuclear translocation, which enhanced Nrf2-ARE transcription capacity and the downstream protein content in a Nrf2 dependent manner. In lipopolysaccharide (LPS)-challenged human HK-2 cells, CPUY192018 exhibited cytoprotective effects by enhancing the Nrf2-ARE regulated antioxidant system and diminished the LPS-induced inflammatory response by hindering the ROS-mediated activation of the NF-κB pathway. In the LPS-induced mouse model of chronic renal inflammation, by activating Nrf2, CPUY192018 treatment balanced renal oxidative stress and suppressed inflammatory responses. Hence, administration of CPUY192018 reduced kidney damage and ameliorated pathological alterations of the glomerulus. Taken together, our study suggested that small-molecule Keap1-Nrf2 PPI inhibitors can activate the Nrf2-based cytoprotective system and protect the kidney from inflammatory injury, raising a potential application of Keap1-Nrf2 PPI inhibitors in the treatment of inflammatory kidney disorders.

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CPUY192018 activated Nrf2-ARE pathway to protect against LPS-induced renal inflammation both in cells and in vivo.

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CPUY192018 also inhibited NF-κB involved inflammatory response both in cells and kidney.

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The development of Keap1-Nrf2 PPI inhibitors may create treatment options for kidney diseases with reduced off-target effects.

Ischaemia reperfusion injury: mechanisms of progression to chronic graft dysfunction

The increasing use of extended criteria organs to meet the demand for kidney transplantation raises an important question of how the severity of early ischaemic injury influences long-term outcomes. Significant acute ischaemic kidney injury is associated with delayed graft function, increased immune-associated events and, ultimately, earlier deterioration of graft function. A comprehensive understanding of immediate molecular events that ensue post-ischaemia and their potential long-term consequences are key to the discovery of novel therapeutic targets. Acute ischaemic injury primarily affects tubular structure and function. Depending on the severity and persistence of the insult, this may resolve completely, leading to restoration of normal function, or be sustained, resulting in persistent renal impairment and progressive functional loss. Long-term effects of acute renal ischaemia are mediated by several mechanisms including hypoxia, HIF-1 activation, endothelial dysfunction leading to vascular rarefaction, sustained pro-inflammatory stimuli involving innate and adaptive immune responses, failure of tubular cells to recover and epigenetic changes. This review describes the biological relevance and interaction of these mechanisms based on currently available evidence.

Gcm1 is involved in cell proliferation and fibrosis during kidney regeneration after ischemia-reperfusion injury

In acute kidney injury (AKI), the S3 segment of the proximal tubule is particularly damaged, as it is most vulnerable to ischemia. However, this region is also involved in renal tubular regeneration. To deeply understand the mechanism of the repair process after ischemic injury in AKI, we focused on glial cells missing 1 (Gcm1), which is one of the genes expressed in the S3 segment. Gcm1 is essential for the development of the placenta, and Gcm1 knockout (KO) is embryonically lethal. Thus, the function of Gcm1 in the kidney has not been analyzed yet. We analyzed the function of Gcm1 in the kidney by specifically knocking out Gcm1 in the kidney. We created an ischemia-reperfusion injury (IRI) model to observe the repair process after AKI. We found that Gcm1 expression was transiently increased during the recovery phase of IRI. In Gcm1 conditional KO mice, during the recovery phase of IRI, tubular cell proliferation reduced and transforming growth factor-β1 expression was downregulated resulting in a reduction in fibrosis. In vitro, Gcm1 overexpression promoted cell proliferation and upregulated TGF-β1 expression. These findings indicate that Gcm1 is involved in the mechanisms of fibrosis and cell proliferation after ischemic injury of the kidney.

Biomarkers of Drug-Induced Kidney Toxicity

Blood urea nitrogen and serum creatinine are imperfect markers of kidney function because they are influenced by many renal and nonrenal factors independent of kidney function. A biomarker that is released directly into the blood or urine by the kidney in response to injury may be a better early marker of drug-induced kidney toxicity than blood urea nitrogen and serum creatinine. Urine albumin and urine protein, as well as urinary markers kidney injury molecule-1 (KIM-1), β2-microglobulin (B2M), cystatin C, clusterin, and trefoil factor-3 (TFF-3) have been accepted by the Food and Drug Administration and European Medicines Agency as highly sensitive and specific urinary biomarkers to monitor drug-induced kidney injury in preclinical studies and on a case-by-case basis in clinical trials. Other biomarkers of drug-induced kidney toxicity that have been detected in the urine of rodents or patients include IL-18, neutrophil gelatinase-associated lipocalin, netrin-1, liver-type fatty acid-binding protein (L-FABP), urinary exosomes, and TIMP2 (insulin-like growth factor-binding protein 7)/IGFBP7 (insulin-like growth factor-binding protein 7), also known as NephroCheck, the first Food and Drug Administration-approved biomarker testing platform to detect acute kidney injury in patients. In the future, a combined use of functional and damage markers may advance the field of biomarkers of drug-induced kidney toxicity. Earlier detection of drug-induced kidney toxicity with a kidney-specific biomarker may result in the avoidance of nephrotoxic agents in clinical studies and may allow for earlier intervention to repair damaged kidneys.

Interleukin-18 in Health and Disease

Interleukin (IL)-18 was originally discovered as a factor that enhanced IFN-γ production from anti-CD3-stimulated Th1 cells, especially in the presence of IL-12. Upon stimulation with Ag plus IL-12, naïve T cells develop into IL-18 receptor (IL-18R) expressing Th1 cells, which increase IFN-γ production in response to IL-18 stimulation. Therefore, IL-12 is a commitment factor that induces the development of Th1 cells. In contrast, IL-18 is a proinflammatory cytokine that facilitates type 1 responses. However, IL-18 without IL-12 but with IL-2, stimulates NK cells, CD4⁺ NKT cells, and established Th1 cells, to produce IL-3, IL-9, and IL-13. Furthermore, together with IL-3, IL-18 stimulates mast cells and basophils to produce IL-4, IL-13, and chemical mediators such as histamine. Therefore, IL-18 is a cytokine that stimulates various cell types and has pleiotropic functions. IL-18 is a member of the IL-1 family of cytokines. IL-18 demonstrates a unique function by binding to a specific receptor expressed on various types of cells. In this review article, we will focus on the unique features of IL-18 in health and disease in experimental animals and humans.

Metformin ameliorated methotrexate-induced hepatorenal toxicity in rats in addition to its antitumor activity: two birds with one stone

Methotrexate (MTX) is a drug used in treatment of various malignancies. Unfortunately, it leads to life-threatening complications including hepatorenal toxicity. Previous studies revealed the protective effects of metformin (MET) on hepatorenal toxicity in other models in addition to its anticancer effects. The current study investigates the effect of MET on MTX-induced hepatorenal toxicity and the possible mechanisms involved in this toxicity which can be overwhelmed by MET. Thirty male rats were divided into 3 groups: normal control, MTX treated and MET/MTX treated. After 7 days, MTX induced hepatorenal toxicity as proved by histological examinations and biochemical analysis of liver and kidney functions. Also, it led to significant increase in hepatic and renal malondialdehyde levels, significant decrease in hepatic and renal total antioxidant capacity levels and Na+/K+-ATPase activities and significant up regulation of mRNA expressions of nuclear factor kappa-light-chain-enhancer of activated B cells, cyclooxygenase-2 and caspase 3 compared with the control group. While, MET could significantly reduce hepatorenal toxicity and counteract the effects of MTX on all measured parameters. In conclusion, MET can be an effective adjuvant to MTX chemotherapy that could ameliorate its hepatorenal toxicity through antioxidant, anti-inflammatory and anti-apoptotic mechanisms.

Hypoxic Preconditioned Mesenchymal Stromal Cell Therapy in a Rat Model of Renal Ischemia-reperfusion Injury: Development of Optimal Protocol to Potentiate Therapeutic Efficacy

Although previous and ongoing clinical studies have used stromal cells during renal ischemia-reperfusion injury (IRI), there is little consensus regarding the optimal protocol. We aimed to optimize the protocol for hypoxic preconditioned human bone marrow-derived mesenchymal stromal cell (HP-hBMSC) therapy in a rat model of renal IRI. We determined the optimal injection route (renal arterial, renal parenchymal, and tail venous injection), dose (low-dose: 1×10⁶, moderate-dose: 2×10⁶, and high-dose: 4×10⁶), and injection period (pre-, concurrent-, and post-IRI). During optimal injection route study, renal arterial injections significantly reduced the decreasing glomerular filtration rate (GFR), as compared to GFRs for the IRI control group, 2 and 4 days after IRI. Therapeutic effects and histological recoveries were the greatest in the group receiving renal arterial injections. During the dose finding study, high-dose injections significantly reduced the decreasing GFR, as compared to GFRs for the IRI control group, 3 days after IRI. Therapeutic effects and histological recoveries were the greatest in the high-dose injection group. While determining the optimal injection timing study, concurrent-IRI injection reduced elevated serum creatinine levels, as compared to those of the IRI control group, 1 day after IRI. Pre-IRI injection significantly reduced the decreasing GFR, as compared with GFRs for the IRI control group, 1 day after IRI. Therapeutic effects and histological recoveries were the greatest in the concurrent-IRI group. In conclusion, the concurrent-IRI administration of a high dose of HP-hBMSC via the renal artery leads to an optimal recovery of renal function after renal IRI.

Tempol Protects Against Acute Renal Injury by Regulating PI3K/Akt/mTOR and GSK3β Signaling Cascades and Afferent Arteriolar Activity

BACKGROUND/AIMS

Free radical scavenger tempol is a protective antioxidant against ischemic injury. Tubular epithelial apoptosis is one of the main changes in the renal ischemia/reperfusion (I/R) injury. Meanwhile some proteins related with apoptosis and inflammation are also involved in renal I/R injury. We tested the hypothesis that tempol protects against renal I/R injury by activating protein kinase B/mammalian target of rapamycin (PKB, Akt/mTOR) and glycogen synthase kinase 3β (GSK3β) pathways as well as the coordinating apoptosis and inflammation related proteins.

METHODS

The right renal pedicle of C57Bl/6 mouse was clamped for 30 minutes and the left kidney was removed in the study. The renal injury was assessed with serum parameters by an automatic chemistry analyzer. Renal expressions of Akt/mTOR and GSK3β pathways were measured by western blot in I/R mice treated with saline or tempol (50mg/kg) and compared with sham-operated mice.

RESULTS

The levels of blood urea nitrogen (BUN), creatinine and superoxide anion (O2.-) increased, and superoxide dismutase (SOD) and catalase (CAT) decreased significantly after renal I/R injury. However, tempol treatment prevented the changes. Besides, I/R injury reduced renal expression of p-Akt, p-GSK3β, p-mTOR, Bcl2 and increased NF-κB, p-JNK and p53 in kidney, tempol significantly normalized these changes. In addition, renal I/R injury reduced the response of afferent arteriole to Angiotensin II (Ang II), while tempol treatment improved the activity of afferent arteriole.

CONCLUSION

Tempol attenuates renal I/R injury. The protective mechanisms seem to relate with activation of PI3K/Akt/mTOR and GSK3β pathways, inhibition of cellular damage markers and inflammation factors, as well as improvement of afferent arteriolar activity.

The anti-caspase inhibitor Q-VD-OPH prevents AIDS disease progression in SIV-infected rhesus macaques

Apoptosis has been proposed as a key mechanism responsible for CD4+ T cell depletion and immune dysfunction during HIV infection. We demonstrated that Q-VD-OPH, a caspase inhibitor, inhibits spontaneous and activation-induced death of T cells from SIV-infected rhesus macaques (RMs). When administered during the acute phase of infection, Q-VD-OPH was associated with (a) reduced levels of T cell death, (b) preservation of CD4+/CD8+ T cell ratio in lymphoid organs and in the gut, (c) maintenance of memory CD4+ T cells, and (d) increased specific CD4+ T cell response associated with the expression of cytotoxic molecules. Although therapy was limited to the acute phase of infection, Q-VD-OPH-treated RMs showed lower levels of both viral load and cell-associated SIV DNA as compared with control SIV-infected RMs throughout the chronic phase of infection, and prevented the development of AIDS. Overall, our data demonstrate that Q-VD-OPH injection in SIV-infected RMs may represent an adjunctive therapeutic agent to control HIV infection and delaying disease progression to AIDS.

First-stage palliation strategy for univentricular heart disease may impact risk for acute kidney injury

OBJECTIVE

Norwood palliation for patients with single ventricle heart disease is associated with a significant risk for acute kidney injury, which portends a worse prognosis. We sought to investigate the impact of hybrid stage I palliation (Hybrid) on acute kidney injury risk.

DESIGN

This study is a single-centre prospective case-control study of seven consecutive neonates with single ventricle undergoing Hybrid palliation. Levels of serum creatinine and four novel urinary biomarkers, namely neutrophil gelatinase-associated lipocalin, interleukin-18, liver fatty acid-binding protein, and kidney injury molecule-1, were obtained before and after palliation. Acute kidney injury was defined as a ⩾50% increase in serum creatinine within 48 hours after the procedure. Data were compared with a contemporary cohort of 12 neonates with single ventricle who underwent Norwood palliation.

RESULTS

Patients who underwent Hybrid were more likely to be high-risk candidates (86 versus 25%, p=0.01) compared with those who underwent Norwood. Despite similar preoperative serum creatinine levels, there was a trend towards higher levels of postoperative peak serum creatinine (0.7 [0.63, 0.94] versus 0.56 [0.47, 0.74], p=0.06) and rate of acute kidney injury (67 versus 29%, p=0.17) in the Norwood cohort. Preoperative neutrophil gelatinase-associated lipocalin (58.4 [11, 86.3] versus 6.3 [5, 16.2], p=0.07) and interleukin-18 (30.6 [9.6, 167.2] versus 6.3 [6.3, 16.4], p=0.03) levels were higher in the Hybrid cohort. Nevertheless, longitudinal mixed-effect models demonstrated Hybrid palliation to be a protective factor against increased postoperative levels of neutrophil gelatinase-associated lipocalin (estimate -1.8 [-3.0, -9.0], p<0.001) and liver fatty acid-binding protein (-49.3 [-89.7, -8.8], p=0.018).

CONCLUSIONS

In this single-centre case-control study, postoperative acute kidney injury risk did not differ significantly by single ventricle stage I treatment strategy; however, postoperative elevation in novel urinary biomarkers, consistent with subclinical kidney injury, was encountered in the Norwood cohort but not in the Hybrid cohort.

Urinary biomarkers of cell cycle arrest are delayed predictors of acute kidney injury after pediatric cardiopulmonary bypass

BACKGROUND

Several novel biomarkers that predict acute kidney injury (AKI) have recently been proposed. We have evaluated the sequential patterns of biomarker elevation after pediatric cardiopulmonary bypass (CPB) and determined their diagnostic accuracy.

METHODS

We measured the ability of neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18), liver type fatty-acid binding protein (L-FABP), kidney injury molecule-1 (KIM-1), tissue inhibitor of metalloproteinase-2 (TIMP-2), and insulin-like growth factor binding protein 7 (IGFBP7), to predict AKI (≥50% increase in serum creatinine from baseline). Areas under the receiver-operator characteristic curves (AUCs) were calculated for each biomarker and for various biomarker combinations at multiple time points after CPB.

RESULTS

Of 150 patients examined, AKI had developed in 50 patients by 24 h after CPB, with an elevated NGAL concentration first noted at 2 h post-CPB, increases in IL-18, L-FABP, and the product of TIMP-2 and IGFBP7 first noted at 6 h, and an elevated KIM-1 level noted at 12 h. At each time point, urine NGAL remained the marker with the highest predictive ability (AUC > 0.9). The addition of any other biomarker did not increase the predictive accuracy of NGAL alone at 2 and 6 h. At 12 h, when compared to NGAL alone, the combination of NGAL, IL-18, and TIMP2 improved the AUC for AKI prediction (from 0.938 to 0.973).

CONCLUSIONS

While urine NGAL remains a superior stand-alone test at the 2 and 6 h time points after pediatric CPB, a panel of carefully selected biomarkers may prove optimal at later time points.

Effects of different storage solutions on renal ischemia tolerance after kidney transplantation in mice

storage is the most prevalent method for graft preservation in kidney transplantation (KTX). The protective effects of various preservation solutions have been studied extensively in both clinical trials and experimental animal models. However, a paucity of studies have examined the effect of different preservation solutions on graft function in mouse KTX; in addition, the tolerance of the transplanted grafts to further insult has not been evaluated, which was the objective of the present study. We performed mouse KTX in three groups, with the donor kidneys preserved in different solutions for 60 min: saline, mouse serum, and University of Wisconsin (UW) solution. The graft functions were assessed by kidney injury markers and glomerular filtration rate (GFR). The grafts that were preserved in UW solution exhibited better functions, reflected by 50 and 70% lower plasma creatinine levels as well as 30 and 55% higher plasma creatinine levels in GFR than serum and saline groups, respectively, during the first week after transplants. To examine the graft function in response to additional insult, we induced ischemia-reperfusion injury (IRI) by clamping the renal pedicle for 18 min at 4 wk after KTX. We found that the grafts preserved in UW solution exhibited ~30 and 20% less injury assessed by kidney injury markers and histology than in other two preservation solutions. Taken together, our results demonstrated that UW solution exhibited a better protective effect in transplanted renal grafts in mice. UW solution is recommended for use in mouse KTX for reducing confounding factors such as IRI during surgery.

The level of urinary IL-18 in acute kidney injury after cardiopulmonary bypass

This study investigated the diagnostic value of urinary interleukin-18 (uIL-18) in acute kidney injury (AKI) after cardiopulmonary bypass (CPB) in clinical practice. A total of 103 patients who underwent CPB were divided into the AKI group and non-AKI group according to the diagnostic criteria of AKI, and we collected the urine samples before and at 2, 4, 6, 8 and 12 h after CPB and the blood samples before and at 12, 24, 48 and 72 h after CPB for detection of the levels of uIL-18 and urinary neutrophil gelatinase-associated lipocalin (uNGAL) in urine samples and the levels of serum creatinine (Scr) in blood samples, respectively. With the results of detection, we measured the sensitivity and specificity of uIL-18 and uNGAL levels at 2 h after CPB in early diagnosis of AKI using the receiver operating characteristic (ROC) curve and area under curve (AUC). There were a total of 22 patients (21.4%) with AKI. From 12 h after CPB, the level of Scr in the AKI group was significantly elevated, and this increasing trend lasted for 60 h; comparisons with the levels before CPB and in non-AKI group showed that the differences had statistical significance (P<0.05). In AKI group, uIL-18 attained the peak level at 2 h after CPB, and the high level lasted for 10 h; comparisons with the levels before CPB and in non-AKI group showed that the differences had statistical significance (P<0.05); 2 h after CPB, the AUC was 90.48, and when the critical value was set as 1.6 µg/l, the sensitivity and specificity was 90.91 and 91.36%, respectively. Although there was a significant elevation in uNGAL level at 2 h after CPB in the AKI group, the level was dramatically decreased as soon as the peak level was attained at 4 h, and the high level only lasted for 8 h; difference between the level at 2 h after CPB and the level before CPB as well as that in the non-AKI group had statistical significance (P<0.05); at 2 h after CPB, the AUC was 83.25, and when the critical value was set as 100 µg/l, the sensitivity and specificity was, respectively 90.91 and 93.83%. The results indicated that after CPB, the level of uIL-18 shows a more promising diagnostic value in clinical practice than Scr and uNGAL in early diagnosis of AKI.

Urine biomarkers of acute kidney injury in noncritically ill, hospitalized children treated with chemotherapy

BACKGROUND

Cisplatin (Cis), carboplatin (Carb), and ifosfamide (Ifos) are common nephrotoxic chemotherapies. Biomarkers of tubular injury may allow for early acute kidney injury (AKI) diagnosis.

PROCEDURE

We performed a two-center (Canada, United States) pilot study to prospectively measure serum creatinine (SCr), urine neutrophil gelatinase-associated lipocalin (NGAL), and interleukin-18 (IL-18) in children receiving Cis/Carb (27 episodes), Ifos (30 episodes), and in 15 hospitalized, nonchemotherapy patients. We defined AKI using the Kidney Disease Improving Global Outcomes (KDIGO) definition. We compared postchemotherapy infusion NGAL and IL-18 concentrations (immediate postdose to 3 days later) to pre-infusion concentrations. We calculated area under the receiver operating characteristic curve (AUC) for postinfusion biomarkers to discriminate for AKI.

RESULTS

Prechemotherapy infusion NGAL and IL-18 concentrations were not higher than nonchemotherapy control concentrations. Increasing chemotherapy dose was associated with increasing postinfusion (0-4 hr after infusion) NGAL (P < 0.05). Post-Ifos, immediate postdose, and daily postdose NGAL and IL-18 were significantly higher than pre-infusion biomarker concentrations (P < 0.05), during AKI episodes. NGAL and IL-18 did not rise significantly after Cis-Carb infusion, relative to predose concentrations (P > 0.05). NGAL and IL-18 measured immediately after Ifos infusion discriminated for AKI with AUCs is 0.80 (standard error = 0.13) and 0.73 (standard error = 0.16), respectively. NGAL and IL-18 were not diagnostic of Cis-Carb-associated AKI. When AUCs were adjusted for age, all biomarker AUCs (Cis-Carb and Ifos) improved.

CONCLUSION

Urine NGAL and IL-18 show promise as early AKI diagnostic tests in children treated with ifosfamide and may have a potential role in drug toxicity monitoring.

Effect of curcumin on glycerol-induced acute kidney injury in rats

The aim of this study was to investigate the protective role and underlying mechanisms of curcumin on glycerol-induced acute kidney injury (AKI) in rats. Glycerol (10 ml/kg BW, 50% v/v in sterile saline, i.m.) was used to induce AKI, followed by curcumin (200 mg/kg/day, p.o.) administration for 3 days. To confirm renal damage and the effects of curcumin on AKI, serum BUN, Scr, and CK as well as renal SOD, MDA, GSH-Px were measured. Additionally, morphological changes were identified by H&E staining and transmission electron microscopy. The expression of several factors including chemotactic factor MCP-1, proinflammatory cytokines including TNF-α and IL-6, as well as the kidney injury markers, as Kim-1 and Lipocalin-2 were also assessed using q-PCR. Finally, cell apoptosis in renal tissue was detected using in situ TUNEL apoptosis fluorescence staining and expression of proteins associated with apoptotic, oxidative stress and lipid oxidative related signaling pathways were detected using immunohistochemical staining and western blot. The results showed that curcumin exerts renoprotective effects by inhibiting oxidative stress in rhabdomyolysis-induced AKI through regulation of the AMPK and Nrf2/HO-1 signaling pathways, and also ameliorated RM-associated renal injury and cell apoptosis by activating the PI3K/Akt pathway.

Urine Interleukin 18 and Lipocalin 2 Are Biomarkers of Acute Tubular Necrosis in Patients With Cirrhosis: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Acute kidney injury (AKI) is a common complication in patients with cirrhosis that increases mortality. The most common causes of AKI in these patients are prerenal azotemia, acute tubular necrosis (ATN), and hepatorenal syndrome; it is important to determine the etiology of AKI to select the proper treatment and predict patient outcome. Urine biomarkers could be used to differentiate between patients with ATN and functional causes of AKI. We performed a systematic review and meta-analysis of published studies to determine whether urine levels of interleukin (IL)18 and lipocalin 2 or neutrophil gelatinase-associated lipocalin (NGAL) are associated with the development of ATN in patients with cirrhosis.

METHODS

We searched MEDLINE, Scopus, ISI Web of Knowledge, and conference abstracts through December 31, 2015, for studies that assessed urine biomarkers for detection of acute kidney injury in patients with cirrhosis or reported an association between urine biomarkers and all-cause mortality in these patients. We included only biomarkers assessed in 3 or more independent studies, searching for terms that included urine biomarkers, cirrhosis, NGAL, and IL18. We calculated the pooled sensitivities and specificities for detection and calculated the area under the receiver operating characteristic curve (AUC) values using a bivariate logistic mixed-effects model. We used the χ² test to assess heterogeneity among studies.

RESULTS

We analyzed data from 8 prospective studies, comprising 1129 patients with cirrhosis. We found urine levels of the markers discriminated between patients with ATN and other types of kidney impairments, with AUC values of 0.88 for IL18 (95% confidence interval [CI], 0.79-0.97) and 0.89 for NGAL (95% CI, 0.84-0.94). Urine levels of IL18 identified patients who would die in the hospital or within 90 days (short-term mortality) with an AUC value of 0.76 (95% CI, 0.68-0.85); NGAL identified these patients with the same AUC (0.76; 95% CI, 0.71-0.82).

CONCLUSIONS

In a systematic review and meta-analysis, we found that urine levels of IL18 and NGAL from patients with cirrhosis discriminate between those with ATN and other types of kidney impairments, with AUC values of 0.88 and 0.89, respectively. Urine levels of IL18 and NGAL identified patients with short-term mortality with an AUC value of 0.76. These biomarkers might be used to determine prognosis and select treatments for patients with cirrhosis.

Biomarkers for Early Acute Kidney Injury Diagnosis and Severity Prediction: A Pilot Multicenter Canadian Study of Children Admitted to the ICU

OBJECTIVE

Acute kidney injury occurs early in PICU admission and increases risks for poor outcomes. We evaluated the feasibility of a multicenter acute kidney injury biomarker urine collection protocol and measured diagnostic characteristics of urine neutrophil gelatinase-associated lipocalin, interleukin-18, and liver fatty acid binding protein to predict acute kidney injury and prolonged acute kidney injury.

DESIGN

Prospective observational pilot cohort study.

SETTING

Four Canadian tertiary healthcare PICUs.

PATIENTS

Eighty-one children 1 month to 18 years old. Exclusion criteria were as follows: cardiac surgery, baseline severe kidney disease, and inadequate urine or serum for PICU days 1-3.

INTERVENTIONS

PICUs performed standardized urine collection protocol to obtain early PICU admission urine samples, with deferred consent.

MEASUREMENTS AND MAIN RESULTS

Study barriers and facilitators were recorded. Acute kidney injury was defined based on Kidney Disease: Improving Global Outcomes serum creatinine criteria (acute kidney injuryserum creatinine) and by serum creatinine and urine output criteria (acute kidney injuryserum creatinine+urine output) Prolonged acute kidney injury was defined as acute kidney injury duration of 48 hours or more. PICU days 1-3 neutrophil gelatinase-associated lipocalin, interleukin-18, and liver fatty acid binding protein were evaluated for acute kidney injury prediction (area under the curve). Biomarkers on the first day of acute kidney injury attainment (day 1 acute kidney injury) were evaluated for predicting prolonged acute kidney injury. Eighty-two to 95% of subjects had urine collected from PICU days 1-3. Acute kidney injuryserum creatinine developed in 16 subjects (20%); acute kidney injuryserum creatinine+urine output developed in 38 (47%). On PICU day 1, interleukin-18 predicted acute kidney injuryserum creatinine with area under the curve=0.82, but neutrophil gelatinase-associated lipocalin and liver fatty acid binding protein predicted acute kidney injuryserum creatinine with area under the curve of less than or equal to 0.69; on PICU day 2, area under the curve was higher (not shown). Interleukin-18 and liver fatty acid binding protein on day 1 acute kidney injury predicted prolonged acute kidney injuryserum creatinine (area under the curve=0.74 and 0.83, respectively). When acute kidney injuryserum creatinine+urine output was used to define acute kidney injury, biomarker area under the curves were globally lower.

CONCLUSIONS

Protocol urine collection to procure early admission samples is feasible. Individual biomarker acute kidney injury prediction performance is highly variable and modest. Larger studies should evaluate utility and cost effectiveness of using early acute kidney injury biomarkers.

Brief Report: Cumulative Tenofovir Disoproxil Fumarate Exposure is Associated With Biomarkers of Tubular Injury and Fibrosis in HIV-Infected Men

Tenofovir disoproxil fumarate (TDF) can cause kidney damage, but current clinical tests are insensitive for detecting toxicity. Among 884 HIV-infected men enrolled in the Multicenter AIDS Cohort Study, we measured urine biomarkers specific for tubular damage (interleukin-18, kidney injury molecule-1, procollagen type III N-terminal propeptide) and albuminuria. In adjusted analyses, each year of TDF exposure was independently associated with 3.3% higher interleukin-18 (95% CI: 0.8% to 5.8%), 3.4% higher kidney injury molecule-1 (1.1% to 5.7%), and 3.1% higher procollagen type III N-terminal propeptide (0.8% to 5.5%), but not with albuminuria (2.8%; -0.6% to 6.2%). Biomarkers of tubular damage may be more sensitive than albuminuria for detecting toxicity from TDF and other medications.

Perspective on Clinical Application of Biomarkers in AKI

Several biomarkers of renal injury have been identified but the utility of these biomarkers is largely confined to research studies, whereas widespread clinical applicability is limited. This is partly because the use of serum creatinine as the comparator has several limitations and restricts the full interpretation of biomarker performance. To highlight the potential for clinical application of biomarkers, the most pertinent biomarker data are summarized here, using clinically relevant scenarios in which biomarkers could assist with diagnostic and management dilemmas. The paradigms proposed in this review aim to enhance the clinical diagnosis, management, and prognosis of AKI through the combined use of available clinical markers and novel inflammatory, injury, and repair biomarkers.

Antithrombin III Protects Against Contrast-Induced Nephropathy

We previously reported that insufficiency of antithrombin III (ATIII), the major anti-coagulation molecule in vivo, exacerbated renal ischemia-reperfusion injury in animal models and possibly humans. In the present study, we investigated the relationship between ATIII level and contrast induced nephropathy (CIN) in patients and examined therapeutic effect of ATIII on CIN in Sprague-Dawley rats. Patients with low ATIII activity presented a higher incidence of acute kidney injury (AKI) following coronary angiography. ATIII (500 μg/kg) was intravenously injected before or after the induction of AKI in rats. Our data demonstrated ATIII significantly attenuated the elevation of serum creatinine, blood urea nitrogen, and renal histological injury. The beneficial effects of ATIII were accompanied by diminished renal inflammatory response, oxidative stress, cell apoptosis and improved renal blood flow in rats. In conclusion, ATIII appears to attenuate CIN through inhibiting inflammation, oxidative stress, apoptosis and improving renal blood flow. ATIII administration may represent a promising strategy for the prevention and treatment of contrast-induced AKI.

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Patients with low ATIII activity presented a higher incidence of acute kidney injury following coronary angiography.

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ATIII supplementation attenuated renal injury in animal models of contrast induced nephropathy.

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ATIII exerted renoprotective effect by inhibiting inflammation, oxidative stress, apoptosis and improving renal blood flow.

Antithrombin III (ATIII), a potent anti-coagulation molecule in vivo, has been reported that it can exert reno-protective effects in ischemia-reperfusion model. Nevertheless, whether exogenous ATIII administration can protect against contrast induced nephropathy (CIN) in animal models remains unclear. This study revealed that ATIII administration has therapeutic effects against CIN in Sprague-Dawley Rats. Furthermore, the reno-protection conferred by ATIII might be mediated by inhibition of inflammation, oxidative stress, apoptosis and improving renal blood flow. ATIII supplementation represents a promising prophylactic and treatment strategies for contrast induced AKI.

Serum Levels of Tumor Necrosis Factor-α and Interleukins in Children with Congenital Heart Disease

Background: Levels of anti-inflammatory cytokines in blood have a positive relationship with congenital heart disease (CHD). We sought to assess the difference in serum cytokines levels between children with and without CHD.  Methods: We recruited 60 patients with CHD and 30 healthy children, from 2013 to 2014. Patients with primary pulmonary hypertension; metabolic diseases; renal, endocrine, and chronic inflammatory diseases; fever; infection in the preceding 3 weeks; and malnutrition were excluded. Participants' demographic data were measured, and their cardiac diseases were diagnosed via echocardiography. Serum levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-18 were measured via ELISA. Results: Mean age of the participants was 4.28 ± 3.44, 3.12 ± 3.87, and 3.30 ± 3.61 years in the cyanotic, acyanotic, and control groups, respectively (p value = 0.414). Mean values of TNF-α (p value < 0.001), IL-6 (p value < 0.001), IL-18 (p value = 0.030), right ventricular pressure (p value < 0.001), and pulmonary pressure (p value = 0.015) were higher in the case group, while the BMI was higher in the controls (p value < 0.001). Mean values of TNF-α (p value < 0.001), IL-6 (p value < 0.001), and right ventricular pressure (p value < 0.001) were significantly higher in the cyanotic children, whereas the BMI was higher in the controls (p value < 0.001). Levels of TNF-α and IL-6 had significant correlations with right ventricular pressure.   Conclusion: The present study showed a differed serum cytokines levels between children with and without CHD.

Implications of dynamic changes in miR-192 expression in ischemic acute kidney injury

Purpose

Ischemia–reperfusion injury (IRI) is a major cause of acute kidney injury (AKI) with poor outcomes. While many important functions of microRNAs (miRNAs) have been identified in various diseases, few studies reported miRNAs in acute kidney IRI, especially the dynamic changes in their expression and their implications during disease progression.

Methods

The expression of miR-192, a specific kidney-enriched miRNA, was assessed in both the plasma and kidney of IRI rats at different time points after kidney injury and compared to renal function and kidney histological changes. The results were validated in the plasma of the selected patients with AKI after cardiac surgery compared with those matched patients without AKI. The performance characteristics of miR-192 were summarized using area under the receiver operator characteristic (ROC) curves (AUC-ROC).

Results

MiRNA profiling in plasma led to the identification of 42 differentially expressed miRNAs in the IRI group compared to the sham group. MiR-192 was kidney-enriched and chosen for further validation. Real-time PCR showed that miR-192 levels increased by fourfold in the plasma and decreased by about 40% in the kidney of IRI rats. Plasma miR-192 expression started increasing at 3 h and peaked at 12 h, while kidney miR-192 expression started decreasing at 6 h and remained at a low level for 7 days after reperfusion. Plasma miR-192 level in patients with AKI increased at the time of ICU admission, was stable for 2 h and decreased after 24 h. AUC-ROC was 0.673 (95% CI: 0.540–0.806, p = 0.014).

Conclusions

Plasma miR-192 expression was induced in a time-dependent manner after IRI in rats and patients with AKI after cardiac surgery, comparably to the kidney injury development and recovery process, and may be useful for the detection of AKI.

Suppression of NLRP3 Inflammasome Activation Ameliorates Chronic Kidney Disease-Induced Cardiac Fibrosis and Diastolic Dysfunction

Cardiac fibrosis is a common finding in patients with chronic kidney disease. Here, we investigate the cardio-renal effects of theracurmin, a novel formulation of the polyphenolic compound curcumin, in a rat model of chronic kidney disease. Briefly, Sprague-Dawley rats were randomized to undergo sham or subtotal nephrectomy (SNx) surgery. At 3 weeks post surgery, SNx animals were further randomized to received theracurmin via once daily oral gavage or vehicle for 5 consecutive weeks. At 8 weeks post surgery, cardiac function was assessed via echocardiography and pressure volume loop analysis, followed by LV and renal tissue collection for analysis. SNx animals developed key hallmarks of renal injury including hypertension, proteinuria, elevated blood urea nitrogen, and glomerulosclerosis. Renal injury in SNx animals was also associated with significant diastolic dysfunction, macrophage infiltration, and cardiac NLRP3 inflammasome activation. Treatment of SNx animals with theracurmin improved structural and functional manifestations of cardiac injury associated with renal failure and also attenuated cardiac NLRP3 inflammasome activation and mature IL-1β release. Taken together, our findings suggest a significant role for the NLRP3 inflammasome in renal injury-induced cardiac dysfunction and presents inflammasome attenuation as a unique strategy to prevent adverse cardiac remodeling in the setting of chronic kidney disease.

A new mouse model of hemorrhagic shock-induced acute kidney injury

Current animal models of hemorrhagic shock-induced acute kidney injury (HS-induced AKI) require extensive surgical procedures and constant monitoring of hemodynamic parameters. Application of these HS-induced AKI models in mice to produce consistent kidney injury is challenging. In the present study, we developed a simple and highly reproducible mouse model of HS-induced AKI by combining moderate bleeding and renal pedicle clamping, which was abbreviated as HS-AKI. HS was induced by retroorbital bleeding of 0.4 ml blood in C57BL/6 mice. Mice were left in HS stage for 30 min, followed by renal pedicle clamping for 18 min at 36.8-37.0°C. Mean arterial pressure (MAP) and heart rate were monitored with preimplanted radio transmitters throughout the experiment. The acute response in renal blood flow (RBF) triggered by HS was measured with transonic flow probe. Mice received sham operation; bleeding alone and renal pedicle clamping alone served as respective controls. MAP was reduced from 77 ± 4 to 35 ± 3 mmHg after bleeding. RBF was reduced by 65% in the HS period. Plasma creatinine and kidney injury molecule-1 levels were increased by more than 22-fold 24 h after reperfusion. GFR was declined by 78% of baseline 3 days after reperfusion. Histological examination revealed a moderate-to-severe acute tubular damage, mostly at the cortex-medulla junction area, followed by the medullar and cortex regions. HS alone did not induce significant kidney injury, but synergistically enhanced pedicle clamping-induced AKI. This is a well-controlled, simple, and reliable mouse model of HS-AKI.

Paternal High Fat Diet in Rats Leads to Renal Accumulation of Lipid and Tubular Changes in Adult Offspring

Along with diabetes and obesity, chronic kidney disease (CKD) is increasing across the globe. Although some data support an effect of maternal obesity on offspring kidney, the impact of paternal obesity is unknown; thus, we have studied the effect of paternal obesity prior to conception. Male Sprague Dawley rats were fed chow diet or high fat diet (HFD) for 13-14 weeks before mating with chow-fed females. Male offspring were weaned onto chow and killed at 27 weeks for renal gene expression and histology. Fathers on HFD were 30% heavier than Controls at mating. At 27 weeks of age offspring of obese fathers weighed 10% less; kidney triglyceride content was significantly increased (5.35 ± 0.84 vs. 2.99 ± 0.47 μg/mg, p < 0.05, n = 8 litters per group. Histological analysis of the kidney demonstrated signs of tubule damage, with significantly greater loss of brush border, and increased cell sloughing in offspring of obese compared to Control fathers. Acat1, involved in entry of fatty acid for beta-oxidation, was significantly upregulated, possibly to counteract increased triglyceride storage. However other genes involved in lipid metabolism, inflammation and kidney injury showed no changes. Paternal obesity was associated with renal triglyceride accumulation and histological changes in tubules, suggesting a mild renal insult in offspring, who may be at risk of developing CKD.

Of Inflammasomes and Alarmins: IL-1β and IL-1α in Kidney Disease

Kidney injury implies danger signaling and a response by the immune system. The inflammasome is a central danger recognition platform that triggers local and systemic inflammation. In immune cells, inflammasome activation causes the release of mature IL-1β and of the alarmin IL-1α Dying cells release IL-1α also, independently of the inflammasome. Both IL-1α and IL-1β ligate the same IL-1 receptor (IL-1R) that is present on nearly all cells inside and outside the kidney, further amplifying cytokine and chemokine release. Thus, the inflammasome-IL-1α/IL-β-IL-1R system is a central element of kidney inflammation and the systemic consequences. Seminal discoveries of recent years have expanded this central paradigm of inflammation. This review gives an overview of arising concepts of inflammasome and IL-1α/β regulation in renal cells and in experimental kidney disease models. There is a pipeline of compounds that can interfere with the inflammasome-IL-1α/IL-β-IL-1R system, ranging from recently described small molecule inhibitors of NLRP3, a component of the inflammasome complex, to regulatory agency-approved IL-1-neutralizing biologic drugs. Based on strong theoretic and experimental rationale, the potential therapeutic benefits of using such compounds to block the inflammasome-IL-1α/IL-β-IL-1R system in kidney disease should be further explored.