Activation of HMGB1-TLR4 Pathway and Inflammasome Contribute to Enhanced Inflammatory Response in Extended Criteria and Kidneys With KDPI ≥85.

BACKGROUND: Metrics for evaluating low-quality kidneys have failed to predict outcomes or reduce the kidney refusal and discard rates. Kidneys from extended-criteria donors (ECDs) and kidneys with ≥85% kidney donor profile indexes (KDPIs) might have different sensitivities to the proinflammatory milieu generated by brain death. We aimed to identify gene expression profile differences in innate immunity pathways between low-quality and ideal kidneys. METHODS: Preimplantation kidney biopsies from ECD (n = 41) and standard-criteria donor (n = 39) were evaluated for real-time quantitative polymerase chain reaction gene expression using the TaqMan Gene Expression Array Plates system for genes Toll-like receptor-4 (TLR4), high-mobility group box 1, nuclear factor kappa beta, myeloid differentiation primary response 88, interferon (IFN)-γ, interleukin (IL)1-ß, tumor necrosis factor alpha, caspase-1 (CASP1), intercellular adhesion molecule 1, IL-10, heme oxygenase 1 hypoxia-inducible factor 1 (HIF-1), monocyte chemotactic protein 1, transforming growth factor beta 1, TIR-domain containing adapter inducing interferon-ß (TRIF), TRIF-related adaptor molecule, interferon regulatory factor 3 (IRF-3), receptor-interacting protein 1, IFNß-1, and nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin protein 3 complex. Gene expression was also evaluated in kidneys with KDPI ≥85. RESULTS: ECD biopsies showed significantly higher expression of IL-10, TLR4, high-mobility group box 1, IFN-γ, TRIF-related adapter molecule, IRF-3, HIF-1, nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin protein 3 complex, CASP1, and IL-1ß (P < 0.05) compared with standard-criteria donor biopsies. IRF-3, HIF-1, and CASP1 were exclusively upregulated in ECD kidneys. Compared with kidneys with KDPIs <85%, kidneys with KDPIs ≥85% had very similar gene transcripts as those observed in ECD kidneys, except that tumor necrosis factor alpha and monocyte chemotactic protein 1 expression was only elevated in kidneys with KDPIs ≥85%. Significant positive correlations were found between the different genes upregulated and the increase in KDPIs. CONCLUSIONS: Our results showed that TLR4 and inflammasome pathways are enhanced in low-quality kidneys and suggest that blocking of some targets might improve transplant outcomes and reduce discard rates.

Preimplantation Kidney Biopsies of Extended Criteria Donors Have a Heavier Inflammatory Burden Than Kidneys From Standard Criteria Donors.

BACKGROUND: Donors after brain death develop a systemic proinflammatory state that may predispose the kidneys to injury after transplantation. Because it is not known whether this inflammatory environment similarly affects the kidneys from expanded criteria donor (ECD) and standard criteria donors (SCD), we sought to evaluate differences in the gene expression of inflammatory cytokines in preimplantation biopsies (PIBx) from ECD and SCD kidneys. METHODS: Cytokines gene expression was measured in 80 PIBx (SCD, 52; ECD, 28) and associated with donor variables. RESULTS: Normal histology and chronic histological lesions were not different between both types of kidneys. ECD kidneys showed significant increase in the transcripts of MCP-1, RANTES, TGF-ß1, and IL-10 when compared with SCD. Kidneys presenting normal histology had similar inflammatory profile except by a higher expression of RANTES observed in ECD (P = 0.04). Interstitial fibrosis and tubular atrophy (interstitial fibrosis and tubular atrophy ≥ 1) were associated with higher expression of TGF-ß1, RANTES, and IL-10 in ECD compared with SCD kidneys. Cold ischemia time of 24 hours or longer was significantly associated with upregulation of FOXP3, MCP-1, RANTES, and IL10, whereas longer duration of donor hospitalization significantly increased gene expression of all markers. High FOXP3 expression was also associated with lower level of serum creatinine at 1 year. Donor age was not associated with any of the transcripts studied. CONCLUSIONS: PIBx of ECD exhibit a higher gene expression of inflammatory cytokines when compared with SCD kidneys. This molecular profile may be a specific ECD kidney response to brain death and may help to predict the posttransplant outcomes of ECD recipients.

Loxosceles gaucho venom-induced acute kidney injury--in vivo and in vitro studies.

BACKGROUND: Accidents caused by Loxosceles spider may cause severe systemic reactions, including acute kidney injury (AKI). There are few experimental studies assessing Loxosceles venom effects on kidney function in vivo. METHODOLOGY/PRINCIPAL FINDINGS: In order to test Loxosceles gaucho venom (LV) nephrotoxicity and to assess some of the possible mechanisms of renal injury, rats were studied up to 60 minutes after LV 0.24 mg/kg or saline IV injection (control). LV caused a sharp and significant drop in glomerular filtration rate, renal blood flow and urinary output and increased renal vascular resistance, without changing blood pressure. Venom infusion increased significantly serum creatine kinase and aspartate aminotransferase. In the LV group renal histology analysis found acute epithelial tubular cells degenerative changes, presence of cell debris and detached epithelial cells in tubular lumen without glomerular or vascular changes. Immunohistochemistry disclosed renal deposition of myoglobin and hemoglobin. LV did not cause injury to a suspension of fresh proximal tubules isolated from rats. CONCLUSIONS/SIGNIFICANCE: Loxosceles gaucho venom injection caused early AKI, which occurred without blood pressure variation. Changes in glomerular function occurred likely due to renal vasoconstriction and rhabdomyolysis. Direct nephrotoxicity could not be demonstrated in vitro. The development of a consistent model of Loxosceles venom-induced AKI and a better understanding of the mechanisms involved in the renal injury may allow more efficient ways to prevent or attenuate the systemic injury after Loxosceles bite.

Loxosceles gaucho Venom-Induced Acute Kidney Injury In Vivo and In Vitro Studies

Accidents caused by Loxosceles spider may cause severe systemic reactions, including acute kidney injury(AKI). There are few experimental studies assessing Loxosceles venom effects on kidney function in vivo.In order to test Loxosceles gaucho venom (LV) nephrotoxicity and to assess some of the possible mechanisms of renal injury, rats were studied up to 60 minutes after LV 0.24 mg/kg or saline IV injection (control). LV caused a sharp and significant drop in glomerular filtration rate, renal blood flow and urinary output and increased renal vascular resistance, without changing blood pressure. Venom infusion increased significantly serum creatine kinase and aspartate aminotransferase. In the LV group renal histology analysis found acute epithelial tubular cells degenerative changes, presence of cell debris and detached epithelial cells in tubular lumen without glomerular or vascular changes.Immunohistochemistry disclosed renal deposition of myoglobin and hemoglobin. LV did not cause injury to a suspension of fresh proximal tubules isolated from rats.

Mechanisms of bee venom-induced acute renal failure.

The spread of Africanized bees in the American continent has increased the number of severe envenomation after swarm attacks. Acute renal failure (ARF) is one of the major hazards in surviving patients. To assess the mechanisms of bee venom-induced ARF, rats were evaluated before, up to 70 min and 24h after 0.5mg/kg of venom injection. Control rats received saline. Bee venom caused an early and significant reduction in glomerular filtration rate (GFR, inulin clearance, 0.84+/-0.05 to 0.40+/-0.08 ml/min/100g, p<0.0001) and renal blood flow (RBF, laser Doppler flowmetry), which was more severe in the cortical (-72%) than in the medullary area (-48%), without systemic blood pressure decrease. Creatine phosphokinase, lactic dehydrogenase (LDH) and serum glutamic oxaloacetic transaminase increased significantly, pointing to rhabdomyolysis, whereas serum glutamic pyruvic transaminase and hematocrit remained stable. Twenty-four hours after venom, RBF recovered but GFR remained significantly impaired. Renal histology showed acute tubular injury and a massive tubular deposition of myoglobin. Venom was added to isolated rat proximal tubules (PT) suspension subjected to normoxia and hypoxia/reoxygenation (H/R) for direct nephrotoxicity evaluation. After 60 min of incubation, 0.1, 2 and 10 microg of venom induced significant increases in LDH release: 47%, 64% and 86%, respectively, vs. 21% in control PT while 2 microg of venom enhanced H/R injury (85% vs. 55%, p<0.01). These results indicate that vasoconstriction, direct nephrotoxicity and rhabdomyolysis are important mechanisms in the installation of bee venom-induced ARF that may occur even without hemolysis or hypotension.