Kidney Injury Molecule-1 Research Articles

Comparison of the Impact of VRP-034 and Polymyxin B upon Markers of Kidney Injury in Human Proximal Tubule Monolayers In Vitro.

In this study, we assessed the impact of commercially available polymyxin B against VRP-034 (novel formulation of polymyxin B) using a validated in vitro human renal model, aProximateTM. Freshly isolated primary proximal tubule cells (PTCs) were cultured in Transwell plates and treated with various concentrations of the formulations for up to 48 h. The functional expression of megalin-cubilin receptors in PTC monolayers was validated using FITC-conjugated albumin uptake assays. Polymyxin B and VRP-034 were evaluated at six concentrations (0.3, 1, 3, 10, 30, and 60 µM), and nephrotoxicity was assessed through measurements of transepithelial electrical resistance (TEER), intracellular adenosine triphosphate (ATP) levels, lactate dehydrogenase (LDH) release, and novel injury biomarkers [kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), and clusterin]. Additionally, histological analysis using annexin V apoptosis staining was performed. Our results indicated a significant decrease in TEER with polymyxin B at concentrations ≥10 μM compared to VRP-034. Toxic effects were observed from ATP and LDH release only at concentrations ≥30 μM for both formulations. Furthermore, injury biomarker release was higher with polymyxin B compared to VRP-034, particularly at concentrations ≥10 µM. Histologically, polymyxin B-treated PTCs showed increased apoptosis compared to VRP-034-treated cells. Overall, VRP-034 demonstrated improved tolerance in the aProximateTM model compared to polymyxin B, suggesting its potential as a safer alternative for renal protection.

Urinary beta-2 microglobulin increases whereas TIMP-2 and IGFBP7 decline after unilateral nephrectomy in healthy kidney donors

Early kidney injury may be detected by urinary markers, such as beta-2 microglobulin (B2M), tissue inhibitor of metalloproteinases-2 (TIMP-2), insulin-like growth factor-binding protein 7 (IGFBP7), kidney injury molecule-1 (KIM-1) and/or neutrophil gelatinase-associated lipocalin (NGAL). Of these biomarkers information on pathophysiology and reference ranges in both healthy and diseased populations are scarce. Differences in urinary levels of B2M, TIMP-2, IGFBP7, KIM-1 and NGAL were compared 24 h before and after nephrectomy in 38 living kidney donors from the REnal Protection Against Ischaemia–Reperfusion in transplantation study. Linear regression was used to assess the relation between baseline biomarker concentration and kidney function 1 year after nephrectomy. Median levels of urinary creatinine and creatinine standardized B2M, TIMP-2, IGFBP7, KIM-1, NGAL, and albumin 24 h before nephrectomy in donors were 9.4 mmol/L, 14 μg/mmol, 16 pmol/mmol, 99 pmol/mmol, 63 ng/mmol, 1390 ng/mmol and 0.7 mg/mmol, with median differences 24 h after nephrectomy of − 0.9, + 1906, − 7.1, − 38.3, − 6.9, + 2378 and + 1.2, respectively. The change of donor eGFR after 12 months per SD increment at baseline of B2M, TIMP-2, IGFBP7, KIM-1 and NGAL was: − 1.1, − 2.3, − 0.7, − 1.6 and − 2.8, respectively. Urinary TIMP-2 and IGFBP7 excretion halved after nephrectomy, similar to urinary creatinine, suggesting these markers predominantly reflect glomerular filtration. B2M and NGAL excretion increased significantly, similar to albumin, indicating decreased proximal tubular reabsorption following nephrectomy. KIM-1 did not change considerably after nephrectomy. Even though none of these biomarkers showed a strong relation with long-term donor eGFR, these results provide valuable insight into the pathophysiology of these urinary biomarkers.

Punicalagin Ameliorating Renal Cell Tumors Against N-Diethylnitrosamine-initiated Iron Nitrilotriacetate-induced Carcinogenesis

Background Renal cell carcinoma, the most prominent kind of adult kidney cancer, lacks early warning symptoms, leading to metastases at the time of diagnosis. Renal cell carcinoma begins with N-diethylnitrosamine (DEN) and is accelerated by ferric nitrilotriacetate (Fe-NTA), which may be a good research model for renal cell carcinoma. Purpose This study was designed to unveil the protective potential of punicalagin against renal cell tumors induced by Fe-NTA in male mice. Methods Renal cancer initiation was achieved through a single intraperitoneal injection of DEN (200 mg/kg body weight (b.wt.)), followed by promotion using Fe-NTA (9 mg Fe/kg b.wt. intraperitoneally) administered twice weekly over 16 weeks. Simultaneously, mice were subjected to punicalagin (10 mg/kg b.wt.) for an uninterrupted 16-week duration. The chemopreventive efficacy of punicalagin was assessed by evaluating antioxidant activities, oxidative stress markers, renal function parameters, histopathological examinations, and immunohistochemical analyses. Results Results showed a significant reduction in DEN and Fe-NTA-mediated lipid peroxidation, concurrent with the amelioration of renal function, as reflected by diminished levels of blood urea nitrogen, creatinine, and kidney injury molecule-1 in punicalagin-treated mice. Furthermore, punicalagin restored the renal antioxidant parameters like superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione in DEN and Fe-NTA-treated mice. Further, it was observed that punicalagin reduces the expression of 8-hydroxy-2′-deoxyguanosine (levels and 4-hydroxy-2-nonenal-modified protein adducts within the kidney tissue. Conclusion These findings were further substantiated by histological examinations. Our current findings indicate that punicalagin might be a potential contender for preventing renal cancer, likely due to its capacity to reduce oxidative stress in laboratory animals.

Circulating kidney injury molecule-1 (KIM-1) biomarker analysis in IMmotion010: A randomized phase 3 study of adjuvant (adj) atezolizumab (atezo) vs placebo (pbo) in patients (pts) with renal cell carcinoma (RCC) at increased risk of recurrence after resection.

4506 Background: In IMmotion010, adj atezo did not prolong investigator-assessed disease-free survival (DFS; primary endpoint) vs pbo after resection in pts with RCC (HR: 0.93, 95% CI: 0.75, 1.15; P=0.50; Pal Lancet 2023). This exploratory analysis of circulating protein biomarkers was performed to identify high-risk pts with minimal residual disease (MRD) who may show differential benefit from treatment (tx) with atezo. Methods: Pts with RCC with clear-cell or sarcomatoid component and increased recurrence risk post nephrectomy were randomized 1:1 to atezo 1200 mg or pbo IV q3w for 16 cycles or 1 year. A retrospective proteomics analysis was done with an affinity-based proximity extension assay (PEA) panel of ≈3000 analytes to identify circulating proteins with differential abundance patterns in matched serum samples (baseline vs at recurrence). A high sensitivity electrochemiluminescence (ECL) assay was then used to evaluate levels of KIM-1, a membrane glycoprotein overexpressed in clear-cell and papillary RCC, in all available baseline and post-tx serum samples. Outcomes in pts with KIM-1 high (≥86 pg/mL) vs low status at baseline were analyzed. Results: In pts with matched PEA samples (n=73), circulating KIM-1 was identified as the most significantly enriched protein at recurrence vs baseline. Of 778 pts enrolled in IMmotion010, 752 (97%) had baseline KIM-1 data (high: 300 [40%]; low: 452 [60%]). KIM-1–high status was associated with reduced DFS, and pts with KIM-1 high had better DFS with atezo vs pbo (Table). Longitudinal analysis of matched samples showed that in KIM-1–high pts, 9% (12/138) and 26% (36/141) of pts had a ≥30% increase from baseline in KIM-1 levels at Cycle 4 Day 1 with atezo vs pbo, compared with 16% (34/213) and 12% (25/207) in KIM-1-low pts, respectively. A ≥30% KIM-1 increase was associated with worse DFS in both KIM-1–high (atezo HR: 1.68, 95% CI: 0.77, 3.69; pbo HR: 3.53, 95% CI: 2.24, 5.58) and KIM-1–low (atezo HR: 3.56, 95% CI 2.21, 5.75; pbo HR: 3.22, 95% CI: 1.81, 5.70) subgroups. In pts with matched ECL samples (n=103), median KIM-1 levels were higher ( P<0.001) at recurrence (172 pg/mL) than at baseline (79 pg/mL). Conclusions: In IMmotion010, high baseline serum KIM-1 levels were associated with poorer prognosis but improved clinical outcomes with atezo vs pbo. Increased post-tx KIM-1 was associated with worse DFS. These data suggest that circulating KIM-1 may be a non-invasive marker of MRD and disease recurrence and be associated with benefit from atezo in adj RCC. Further investigation of KIM-1 in adj RCC is warranted. Clinical trial information: NCT03024996 . [Table: see text]

Biomarkers in acute kidney injury and cirrhosis

The use of biomarkers for managing acute kidney injury (AKI) is still not routinely used in clinical practice due to the lack of robust evidence on their impact on patient outcomes. In cirrhotic patients’ serum creatinine (sCr) limitations are more pronounced, as malnutrition, altered volume status, and muscle mass loss are more frequently encountered. This can make the diagnosis of AKI challenging, and therefore, additional markers may be necessary for a more accurate evaluation. This review will discuss the renal biomarkers of filtration and injury in patients with cirrhosis, focusing on their possible clinical application. A combined evaluation of a panel of biomarkers could provide a comprehensive assessment of kidney function and help distinguish between hepatorenal syndrome and chronic kidney disease in situations involving liver or combined liver and kidney transplantation. We will demonstrate that some biomarkers have more evidence of their utility in cirrhotic patients, such as cystatin C for filtration. In contrast, others require further studies, such as proenkephalin, which is only used in liver transplantation and appears superior to cystatin C as the inflammatory state does not influence it in cirrhotic patients. Interleukin-18 (IL-18) as a biomarker of injury in renal dysfunction in cirrhotic patients is still unclear despite extensive analysis in various scenarios, including liver diseases. On the other hand, the utility of neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) is well established in renal dysfunction and evaluating other outcomes.

Diagnostic efficacy of urinary neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 for early detection of acute kidney injury in dogs with leptospirosis or babesiosis.

This study evaluates the diagnostic efficacy of urinary biomarkers, Neutrophil Gelatinase-Associated Lipocalin (uNGAL), and Kidney Injury Molecule-1 (uKIM-1), in identifying Acute Kidney Injury (AKI) in dogs affected with leptospirosis or babesiosis. Acute kidney injury was diagnosed based on the increase in serum creatinine levels above 0.3mg/dL within 48h and dogs were categorized according to AKI grades based on International Renal Interest Society guidelines. Traditional biomarkers (serum creatinine and blood urea nitrogen) and novel biomarkers like urinary NGAL and urinary KIM-1 levels were measured and compared to concentrations obtained in control dogs. Statistical analysis assessed significant differences (P < 0.01) across AKI grades, specifically noting elevated urinary NGAL and KIM-1 in IRIS grade I AKI (P < 0.001). The study highlights the diagnostic significance of urinary NGAL and KIM-1 as early indicators of renal damage, particularly valuable in non-azotemic AKI cases, offering promising markers for early AKI diagnosis in veterinary clinical settings. These biomarkers demonstrate clinical utility and underscore their potential for improving AKI management in veterinary medicine. Further validation studies involving larger cohorts and diverse etiologies of AKI are needed to confirm the diagnostic accuracy and clinical utility of urinary NGAL and KIM-1 in veterinary practice.

Elevated Serum KIM-1 in Sepsis Correlates with Kidney Dysfunction and the Severity of Multi-Organ Critical Illness.

The kidney injury molecule (KIM)-1 is shed from proximal tubular cells in acute kidney injury (AKI), relaying tubular epithelial proliferation. Additionally, KIM-1 portends complex immunoregulation and is elevated after exposure to lipopolysaccharides. It thus may represent a biomarker in critical illness, sepsis, and sepsis-associated AKI (SA-AKI). To characterise and compare KIM-1 in these settings, we analysed KIM-1 serum concentrations in 192 critically ill patients admitted to the intensive care unit. Irrespective of kidney dysfunction, KIM-1 serum levels were significantly higher in patients with sepsis compared with other critical illnesses (191.6 vs. 132.2 pg/mL, p = 0.019) and were highest in patients with urogenital sepsis, followed by liver failure. Furthermore, KIM-1 levels were significantly elevated in critically ill patients who developed AKI within 48 h (273.3 vs. 125.8 pg/mL, p = 0.026) or later received renal replacement therapy (RRT) (299.7 vs. 146.3 pg/mL, p < 0.001). KIM-1 correlated with markers of renal function, inflammatory parameters, hematopoietic function, and cholangiocellular injury. Among subcomponents of the SOFA score, KIM-1 was elevated in patients with hyperbilirubinaemia (>2 mg/dL, p < 0.001) and thrombocytopenia (<150/nL, p = 0.018). In univariate and multivariate regression analyses, KIM-1 predicted sepsis, the need for RRT, and multi-organ dysfunction (MOD, SOFA > 12 and APACHE II ≥ 20) on the day of admission, adjusting for relevant comorbidities, bilirubin, and platelet count. Additionally, KIM-1 in multivariate regression was able to predict sepsis in patients without prior (CKD) or present (AKI) kidney injury. Our study suggests that next to its established role as a biomarker in kidney dysfunction, KIM-1 is associated with sepsis, biliary injury, and critical illness severity. It thus may offer aid for risk stratification in these patients.

Investigation of reno-protective efficacy of thymoquinone in a unilateral hydronephrosis model

ABSTRACT We aimed to evaluate the effects of the antioxidant thymoquinone on treated and untreated kidneys on histological and oxidative parameters as well as Kidney Injury Molecule (KIM-1) levels in an experimental unilateral ureteropelvic junction obstruction (UPJO) with resultant hydronephrosis (HN) model. In adherence to the Animal research: reporting of in vivo exepriments guidelines, 34 male Wistar rats were randomly divided into four groups which were named accordingly: “CO” (corn oil), “TQ” (thymoquinone and corn oil), “HNCO” (UPJO-HN and corn oil), “HNTQ” (UPJO-HN, thymoquinone and corn oil). Histologically, pelvic epithelial damage, glomerular shrinkage and sclerosis, tubular damage, interstitial edema-inflammation-fibrosis (IEIF), and vascular congestion were assessed. Biochemically, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione reductase (GR) and KIM-1 levels were assessed. Macroscopic HN developed in all obstructed kidneys. Ipsilateral obstructed kidneys deteriorated in all histological parameters. Thymoquinone attenuated glomerular shrinkage and sclerosis alterations but increased vascular congestion. Contralateral non-obstructed kidneys also showed histological deterioration. Thymoquinone had beneficial effects in terms of IEIF presence in contralateral kidneys but it increased vascular congestion. MDA and SOD results were inconclusive. UPJO caused decreased GR levels in the ipsilateral kidneys but not in the contralateral ones. This effect was not ameliorated by thymoquinone treatment. KIM-1 levels were increased in ipsilateral obstructed kidneys with a lower level in HNTQ group than in HNCO. KIM-1 level of the ipsilateral HNTQ group was higher than in both non-obstructed ipsilateral kidney groups. The effect of thymoquinone in ameliorating bilaterally observed histological alterations was limited and controversial. Oxidative damage detected by GR measurements was not prevented by thymoquinone. Thymoquinone partially decreased the damage as evidenced by reduced KIM-1 levels in thymoquinone-treated obstructed kidneys.

#2158 Circulating kidney injury molecule-1 a valuable marker of mortality in hemodialysis patients?

Abstract Background and Aims The importance of finding reliable biomarkers of mortality in CKD, and especially in patients treated with hemodialysis has become evident. Plasma KIM-1 has been mentioned as a marker of cardiovascular morbidity.. The aim of this study is to assess the level of plasma Kidney Injury Molecule- 1 (KIM-1) as a marker of mortality in patients treated with hemodialysis. Method We conducted a single-center study that included 63 CKD G5D patients (hemodialysis for 1-5 years) followed up for 48 months and a control group consisting of 52 patients diagnosed with CKD stages G1-G5, without HfrEF. All patients have been assessed at baseline, regarding cardiovascular disease (medical history, echocardiography and ECG). Circulating plasma KIM-1 levels were determined with single molecule counting immunoassay technology using the Enzyme-linked immunosorbent assay, we performed using standard methods blood biochemistry, and markers of inflammation (CRP, IL-6) and markers of anemia (complete blood count, serum ferritin, transferrin saturation- TSAT). Results Mean plasma KIM1 levels were 403.8 +/-546.8pg/ml) in the group of patients treated with hemodialysis, and was statistically significantly higher compared to the level in the control group (217.48 +/-267.10 pg/ml). In the group of patients treated with hemodialysis plasma KIM-1 levels showed a statistically significant correlation with inflammation (mean CRP- R=0.28, p=0.02 and IL6- R=0.36, p=0.005) and with anemia (hematocrit- R= -0.5, p=-0,0316; hemoglobin - R= -0.5, p=0.02 We found out using ANOVA that patients which presented left ventricular hypertrophy on echocardiography (37 out of 62) had significantly lower mean levels of plasma KIM-1 (155,51 vs 432,12 pg/ml; p=0,026). The group of patients with vascular calcifications on echocardiography (48 out of 62) had lower levels of serum KIM1 (210.01 vs 462.58 pg/ml, p=0.04). After 24 months of follow up we found a mortality rate of 22.23%, while after 48 months the mortality rate was of 50.73%. Using a Cox proportion-hazards regression analysis of predicting factors of mortality we found that regarding the relationship between plasma levels of KIM-1 and mortality there is a significantly decreased survival in patients with low KIM-1&amp;lt;81.98 pg/ml (p&amp;lt;0.001), with a cut-off point for plasma KIM-1 levels= 81.98 pg/ml. Conclusion Plasma KIM-1 levels were significantly higher in patients treated with hemodialysis compared to the control group (ND CKD patients). However, surprisingly, low levels of plasma KIM1 were associated with some cardiovascular changes and also to an increased risk of mortality (at 4 years, not after few months).

#1554 The association between gut-derived metabolites and biomarkers of renal and cerebro-vascular damage in type 2 diabetes mellitus patients

Abstract Background and Aims Due to its numerous complications, type 2 diabetes mellitus (T2DM) has a major impact on the global economic burden and overall mortality. This condition modifies the metabolic microenvironment in targeted organs, such as the kidney and the brain, by its hyperglycemic nature. Gut microbiota seems to have significant interference with the renal-cerebral axis, especially in a dysbiosis state. The aim of the study was to quantify gut derived metabolites by metabolomic techniques and to evaluate their association with markers of endothelial, podocyte and proximal tubule damage and with cerebro-vascular hemodynamic indices. Method The metabolomic profiling was realized on serum and urine samples originated from 90 T2DM patients, divided into three subgroups, such as the following: 30 normal to mildly-, 30 moderately-, and 30 severely increased albuminuria, respectively, and 20 healthy subjects. The samples were examined by using untargeted and targeted ultra-high performance liquid chromatography coupled with electrospray-ionization quadroupole time-of-flight mass spectrometry (UHPLC-QTOF-ESI+-MS), in order to obtain the metabolic profile. The markers of renal damage such as synaptopodin (SP), podocalyxin (PD), N-acetyl-β-D-glucosaminidase (NAG), kidney injury molecule 1 (KIM-1), monocyte chemotactic protein 1 (MCP-1), and intercellular adhesion molecule 1 (ICAM-1) were assessed by ELISA technique. The hemodynamic cerebro-vascular indices were obtained by high resolution Doppler ultrasound of common carotid arteries (CCAs), internal carotid arteries (ICAs), and middle cerebral arteries (MCAs), bilaterally. The correlations between the metabolites, the markers of renal damage, and neurosonological indices were realized by univariable and multivariable linear regression analyses. Results UHPLC-QTOF-ESI+-MS targeted analysis and subsequent statistical assessments revealed a subset of metabolites with a specific pattern for the normal to mildly increased albuminuria subgroup. The metabolites identified as significant were, in serum: arginine (sArg), hippuric acid (sHA), indoxyl sulfate (sIS), butenoylcarnitine (sBCA), sorbitol (sSorb); and in urine, arginine (uArg), butenoylcarnitine (uBCA), indoxyl sulfate (uIS) and p-cresyl sulfate (uPCS). The univariable linear regression analysis revealed that sArg correlated positively with the breath-holding index (BHI) and negatively with intima media thickness (IMT) in ACI, MCP-1 and ICAM-1; sIS, sSorb, and sBCA correlated inversely with these parametes. The multivariable linear regression analysis displayed the specific correlations between metabolites, markers of endothelial dysfunction, and neurosonological indices, such as follows: sArg correlated with IMT and ICAM-1; sIS followed a predictive pattern along with resistance index (RI) in ACIs and ICAM-1; sBCA correlated with IMT and MCP-1 and sSorb correlated with ICAM-1 and BHI. The urine metabolites were correlated with markers of podocyte and proximal tubule dysfunction: uIS and uBCA were correlated with PD and urinary albumin to-creatinin ratio (uACR), and uPCR correlated with KIM-1 and uACR. Conclusion This study revealed a set of metabolites potentially derived from the intestinal microflora which may act as biomarkers for the early detection of both CMA and DKD in T2DM patients. SArg, sIS and, sBCA are indicators of renal endothelial dysfunction. Moreover, sArg and sIS reflect incipient common and internal carotid artery atherosclerosis, suggesting vascular remodeling at these levels. SSorb correlated with BHI, indicating blood-brain barrier dysfunction and CMA development. In urine, uBCA and uIS are indicators of podocytopathy, whereas uPCS is associated with proximal tubule damage in incipient DKD.

#1323 Kidney health in children with X-linked hypophosphatemia: lessons from the prospective multicenter study in Germany and Switzerland

Abstract Background and Aims X-linked hypophosphatemia (XLH) is the most common genetic cause of hypophosphatemia. Mutations in the PHEX gene cause elevated circulating levels of fibroblast growth factor 23 (FGF23), phosphaturia, rickets and osteomalacia. Conventional treatment with phosphate salts and active vitamin D is associated with nephrocalcinosis and preclinical studies in mice have shown that a chronic high phosphate load causes proximal tubular injury and fibrosis. There is no detailed analysis on kidney health in XLH patients yet. Method We conduct a prospective observational multicenter study in Germany and Switzerland to evaluate kidney health in pediatric XLH patients. Patients receive conventional therapy or burosumab, a fully humanized anti-FGF23 antibody. Clinical and biochemical data, blood and urine samples are collected annually. Results To date, 137 patients (80 girls, mean age 10.5 years) from 40 centers are included. 22% of patients have been treated conventionally for 7.5 years, 78% of patients have received burosumab for 2.3 years with 3.7 years of conventional therapy beforehand. Children with XLH show increased systolic blood pressure and body mass index (BMI), and overweight (BMI &amp;gt;90th percentile) and hypertension (systolic blood pressure &amp;gt;95th percentile) were each found in 20% of patients. A reduced eGFR (&amp;lt;90 ml/min/1.73 m2) and/or nephrocalcinosis was noted in 7% and 28% of patients, respectively. Microalbuminuria is twice as prevalent in children with XLH as in healthy children (14% vs 7%). Urinary lithogenic substances (calcium, oxalate, glycolate) are increased in 1.8-22.8%, and citrate is decreased in 12.3% of XLH patients. Tubular injury markers neutrophil gelatinase-associated lipocalin (NGAL) and Dickkopf-3 (DKK3) are elevated in urine of children with XLH, Chitinase 3-like 1 (CHl3L1) is comparable to children with chronic kidney disease, while kidney injury molecule-1 (Kim-1), indicating proximal tubule cell injury, is within a normal range. The renal inflammation marker monocyte chemoattractant protein-1 (MCP-1) is elevated in children with XLH, and epidermal growth factor (EGF), a marker of tubular cell repair, is decreased compared to healthy adults. Conclusion Pediatric XLH patients on conventional or burosumab therapy show enhanced systolic blood pressure slightly associated with elevated BMI, and significant renal comorbidity, i.e. reduced eGFR, nephrocalcinosis, increased urinary lithogenic substances, elevated urinary markers of glomerular and tubular injury and inflammation. The impact of conventional versus burosumab treatment are still being investigated.

Zn2+ improves sepsis-induced acute kidney injury by upregulating SIRT7-mediated Parkin acetylation.

Zn2+ levels are reported to be correlated with kidney function. We explored the significance of Zn2+ in sepsis-induced acute kidney injury (SI-AKI) through the regulation of sirtuin 7 (SIRT7) activity. The sepsis rat model was established by cecal ligation and perforation (CLP) and intraperitoneally injected with ZnSO4 or SIRT7 inhibitor 97491 (SIRT7i), with renal tubular injury assessed by hematoxylin and eosin staining. In vitro, human renal tubular epithelial cells (HK-2) were induced with lipopolysaccharide to obtain a renal injury cell model, followed by ZnSO4 or SIRT7i and autophagy inhibitor (3-methyladenine) treatment. Interleukin (IL)-1β, IL-18, reactive oxygen species (ROS), Parkin acetylation level, kidney injury molecule-1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL) expression levels were determined. The renal tubule injury, inflammation condition, and pyroptosis-related and autophagy-related protein levels were assessed. The pyroptosis in kidney tissues and autophagosome formation were observed by transmission electron microscopy. Zn2+ alleviated renal injury in CLP rats and inhibited pyroptosis and its related protein levels by inhibiting SIRT7 activity in septic rat renal tissues. In vitro, Zn2+ increased HK-2 cell viability and reduced KIM-1, NGAL, IL-1β, IL-18, NLRP3 inflammasome, cleaved caspase-1, gasdermin D-N levels, and pyroptotic cell number. Zn2+ increased autophagosome number and LC3BII/LC3BI ratio and decreased TOM20, TIM23, P62, and mitochondrial ROS levels. Zn2+ increased Parkin acetylation by repressing SIRT7 activity. Inhibiting mitophagy partially averted Zn2+-inhibited NLRP3 inflammasome activation and apoptosis in HK-2 cells. Zn2+ upregulated Parkin acetylation by repressing SIRT7 activity to promote mitophagy and inhibit NLRP3 inflammasome activation and pyroptosis, thus improving SI-AKI.NEW & NOTEWORTHY Zn2+ upregulated Parkin acetylation by repressing sirtuin 7 activity to promote mitophagy and inhibit NLRP3 inflammasome activation and pyroptosis, thus improving sepsis-induced acute kidney injury.

#57 Tubular biomarkers in proteinuric kidney diseases

Abstract Background and Aims Proteinuria is not only a biomarker of chronic kidney disease (CKD) and a risk predictor of adverse outcomes but also a driver of kidney disease progression. The excessive filtration of plasma proteins through the glomerular filtration barrier exerts a toxic effect on tubular cells which ultimately leads to fibrosis and end-stage kidney disease (ESKD. The aim of this study was to assess the levels of various tubular biomarkers in both serum and urine in patients with biopsied glomerular and proteinuric kidney diseases, and correlate them with renal histology and kidney outcomes. Method A retrospective study and observational study was conducted at a single center from January 2016 to December 2021. Serum and urine samples were collected on the same day of renal biopsy and were correlated with histological data from a cohort of 156 patients with proteinuric kidney diseases. Kidney outcomes were registered during a median follow-up period of 26 months and defined as a decrease in eGFR ≥ 40% from baseline or the development of end-stage kidney disease. The following urinary markers, adjusted to urine creatinine, were analyzed: β2-mcg (beta 2 microglobulin), α1-mcg (alpha 1 microglobulin), NGAL (Neutrophil Gelatinase-Associated Lipocalin), uKIM-1 (Kidney Injury Molecule-1), MCP-1 (Monocyte Chemoattractant Protein-1), uDKK-3 (urinary Dickkopf-3), and uUMOD (uromodulin). Serum markers sKIM-1 and uUMOD were also collected. Results Regarding the etiology of proteinuric kidney disease, the majority corresponded to glomerular disease (68.6%) followed by diabetic kidney disease (12.8%). Higher levels of proteinuria were associated with increased values of β2-mcg and α1-mcg levels and low levels of uUMOD and sUMOD. A significant correlation between the extent of interstitial fibrosis and specific biomarkers was observed: uDKK3 (rho = 0.804, p &amp;lt; 0.001), sKIM-1 (rho = 0.472, p &amp;lt; 0.001), sUMOD (rho = −0.370, p &amp;lt; 0.001), uUMOD (rho = −0.317, p &amp;lt; 0.001), MCP-1 (rho = 0.374, p &amp;lt; 0.001), uKIM-1 (rho = 0.368, p &amp;lt; 0.001), and β2-mcg (rho = 0.392, p &amp;lt; 0.001). Multivariate regression analysis identified uDKK3 as an independent predictor of interstitial fibrosis (Beta 0.728, p &amp;lt; 0.001) adjusted for age, serum creatinine and proteinuria. Elevated levels of MCP-1 and uKIM-1 were associated with a higher risk of significant cortical interstitial inflammation &amp;gt;10% in the logistic regression analysis adjusted for eGFR, proteinuria, and microhematuria: MCP-1 OR = 5.14, 95% CI (2.27−11.62), p &amp;lt; 0.001 and uKIM-1 OR = 1.64, 95% CI (1.05−2.58), p = 0.031. Patients with higher tertiles of β2mcg, MCP1, uDKK3, and KIM1s, and lower tertiles of uUMOD and sUMOD experienced a significantly reduced renal event-free survival in the analysis of Kaplan-Meier model (Fig.). Moreover, of all the evaluated markers, uDKK3 was identified as the best predictor of renal events [HR = 1.03, 95% CI (1.01−1.06), p = 0.008], independently of age, baseline eGFR, proteinuria, and the extent of interstitial fibrosis at the time of renal biopsy. Conclusion Tubular biomarkers may offer prognostic value in proteinuric kidney diseases, particularly uDKK3, exhibiting a notable correlation with interstitial fibrosis and serving as a potential predictor of CKD progression.

#1868 Dapagliflozin reduces urinary kidney injury biomarkers in chronic kidney disease irrespective of albuminuria level

Abstract Background and Aims The beneficial effects of Sodium-Glucose Cotransporter 2(SGLT2) inhibitor in patients with chronic kidney disease (CKD) with low albuminuria levels have not been established. In this study, we aimed to compare the effects of dapagliflozin on kidney injury biomarkers in patients with CKD stratified by albuminuria level. Method We prospectively enrolled healthy volunteers (HVs) (n = 20) and patients with CKD (n = 54) with and without diabetes mellitus (DM). Patients with CKD were divided into two subgroups by age- and sex-matched according to urinary albumin-creatinine ratio (uACR) levels (&amp;lt;300 mg/g and ≥300 mg/g). The CKD group received dapagliflozin 10 mg per day. Urine samples were collected before treatment and after 3 months and 6 months of dapagliflozin. Urinary kidney injury molecule-1 (KIM-1), interleukin-1β (IL-1β), and mitochondrial DNA nicotinamide adenine dinucleotide dehydrogenase subunit-1 (mtND1) copy number were measured. Results The estimated glomerular filtration rate (eGFR) of patients with CKD was lower than that of HVs (p &amp;lt; 0.001). During the study period, eGFR decreased and uACR did not change in the CKD group. Kidney injury markers were significantly elevated in patients with CKD compared with those in HVs. Dapagliflozin reduced urinary KIM-1, IL-1β and mtDNA copy number in patients with CKD after 6 months of treatment. In further, the levels of urinary KIM-1 and IL-1β, patients with CKD decreased after 6 months of dapagliflozin treatment regardless of albuminuria level. Conclusion In this study, dapagliflozin reduced urinary kidney injury biomarkers in patients with CKD, regardless of albuminuria level. These findings suggest that SGLT2i may also attenuate the progression of low albuminuric CKD.

Myeloid-specific ferritin light chain deletion does not exacerbate sepsis-associated AKI.

Sepsis-associated acute kidney injury (SA-AKI) is a key contributor to the life-threatening sequelae attributed to sepsis. Mechanistically, SA-AKI is a consequence of unabated myeloid cell activation and oxidative stress that induces tubular injury. Iron mediates inflammatory pathways directly and through regulating the expression of myeloid-derived ferritin, an iron storage protein comprising ferritin light (FtL) and ferritin heavy chain (FtH) subunits. Previous work revealed that myeloid FtH deletion leads to a compensatory increase in intracellular and circulating FtL and is associated with amelioration of SA-AKI. We designed this study to test the hypothesis that loss of myeloid FtL and subsequently, circulating FtL will exacerbate the sepsis-induced inflammatory response and worsen SA-AKI. We generated a novel myeloid-specific FtL knockout mouse (FtLLysM-/-) and induced sepsis via cecal ligation and puncture or lipopolysaccharide endotoxemia. As expected, serum ferritin levels were significantly lower in the knockout mice, suggesting that myeloid cells dominantly contribute to circulating ferritin. Interestingly, although sepsis induction led to a marked production of pro- and anti-inflammatory cytokines, there was no statistical difference between the genotypes. There was a similar loss of kidney function, as evidenced by a rise in serum creatinine and cystatin C and renal injury identified by expression of kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin. Finally, RNA sequencing revealed upregulation of pathways for cell cycle arrest and autophagy postsepsis, but no significant differences were observed between genotypes, including in key genes associated with ferroptosis, an iron-mediated form of cell death. The loss of FtL did not impact sepsis-mediated activation of NF-κB or HIF-1a signaling, key inflammatory pathways associated with dysregulated host response. Taken together, while FtL overexpression was shown to be protective against sepsis, the loss of FtL did not influence sepsis pathogenesis.NEW & NOTEWORTHY Hyperferritinemia in sepsis is often associated with a proinflammatory phenotype and poor prognosis. We previously showed the myeloid deletion of FtH results in a compensatory increase in FtL and is associated with reduced circulating cytokines and decreased rates of SA-AKI in animal sepsis models. Here, we show that myeloid deletion of FtL does not impact the severity of SA-AKI following CLP or LPS, suggesting that FtH plays the predominant role in propagating myeloid-induced proinflammatory pathways.

#976 Empagliflozin limits AKI incidence and severity following cardiac surgery: an open-label phase IV randomized pilot study

Abstract Background and Aims Cardiac surgery-associated acute kidney injury (CSA-AKI) is a frequent complication of cardiac surgery assisted by cardiopulmonary bypass (CPB). Currently, no effective preventative strategies exist to reduce the incidence of acute kidney injury (AKI). Sodium-glucose transport protein 2 (SGLT2) inhibitors are effective in reducing the incidence of AKI in studies conducted in patients with chronic kidney disease. Therefore, we hypothesized that perioperative SGLT2 inhibition could reduce the incidence of CSA-AKI. Method In this open-label phase IV, randomized, parallel-group, balanced (1:1), pilot study, adult patients undergoing elective cardiac surgery with CPB were randomized to receive 10 mg empagliflozin per os once daily three days before surgery until two days after surgery, or standard care. The primary outcome was AKI incidence according to the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Other outcomes included hypoxia-inducible factor 1 alpha (HIF1A) and urinary Kidney Injury Molecule (KIM-1), urinary neutrophil gelatinase associated lipocalin (NGAL) and metabolic parameters such as plasma ketone and glucose concentrations. Results Between March 2022 and April 2023, 60 patients were randomized to empagliflozin (n = 29) or control (n = 31). All patients who underwent cardiac surgery with CPB were included in the intention-to-treat analysis (n = 25; empagliflozin group, n = 30; control group). SGLT2 inhibition significantly reduced the incidence of all stages of AKI (20% vs 66.7%; absolute difference 46%, 95% CI .13 to .63, P &amp;lt; .001). This decline in AKI incidence was reflected in the kidney biomarkers. SGLT2 inhibition also significantly reduced the number of patients with postoperative hyperglycemia (28% vs 60%; absolute difference 32%, 95% CI −56.8 to −7.2, P = .029). We observed no differences in the incidence of neither ketoacidosis nor hypoglycemic events. Conclusion Perioperative SGLT2 inhibition, compared with standard of care, demonstrated a significant reduction in AKI incidence rates. These findings merit validation in a larger placebo-controlled trial which is currently ongoing. Supplementary figures:

Urine Epidermal Growth Factor and Kidney Function Decline in Middle-Aged Adults

The diagnosis and prognostication of chronic kidney disease (CKD) largely rely on glomerular measures that may not reflect tubular damage. We investigated the associations of urine kidney tubule biomarkers with estimated glomerular filtration rate (eGFR) change among middle-aged adults, when chronic diseases typically emerge. An observational cohort study. A total of 1,145 participants of the Coronary Artery Risk Development in Young Adults (CARDIA) study without CKD, hypertension, or cardiovascular disease at the year 20 visit. Seven different biomarkers of tubular health: urine epidermal growth factor (EGF), alpha-1-microglobulin (α1m), interleukin-18, kidney injury molecule-1, monocyte chemoattractant protein-1, uromodulin, and chitinase-3-like protein1. Ten-year eGFR change and incident reduced eGFR (new onset of eGFR<60mL/min/1.73m2). We examined associations of tubular health biomarkers with 10-year eGFR change and incident reduced eGFR with linear mixed models and interval-censored proportional hazards regression models, respectively. Both minimally and fully adjusted models were controlled for urine creatinine levels. The mean age of participants was 44.8±3.7 years, with 39% African American and 56% female. The average 10-year change in eGFR was -18.6mL/min/1.73m2 (95% CI, -19.4 to -17.8). In contrast to the other tubular biomarkers, which showed conflicting results, EGF demonstrated strong, consistent associations with both kidney outcomes. Each 1-standard deviation (SD) higher EGF was associated with a 2.37mL/min/1.73m2 (95% CI, 0.64-4.10) smaller 10-year decrease in eGFR and a 42% (95% CI, 4%-64%) lower risk of incident reduced eGFR in the fully adjusted model. Observational design, measurements of eGFR were done only at 5-year intervals during follow-up. In middle-aged, community-dwelling adults without hypertension, cardiovascular disease or CKD, higher urine EGF concentrations are associated with slower eGFR decline, whereas other kidney tubule biomarkers lacked a consistent association with kidney function decline.

The Influence of Tacrolimus Exposure and Metabolism on the Outcomes of Kidney Transplants.

Tacrolimus (TAC) has a narrow therapeutic window and patient-specific pharmacokinetic variability. In our study, we analyzed the association between TAC exposure, metabolism, and kidney graft outcomes (function, rejection, and histological lesions). TAC trough (C0), coefficient of variation (TAC CV), concentration/dose ratio (C/D), and biomarkers related to kidney injury molecule-1 (KIM-1) and neutrophil gelatinase lipocalin (NGAL) were analyzed. We examined 174 patients who were subjected to a triple immunosuppressive regimen and underwent kidney transplantation between 2017 and 2022. Surveillance biopsies were performed at the time of kidney implantation and at three and twelve months after transplantation. We classified patients based on their Tac C/D ratios, classifying them as fast (C/D ratio < 1.05 ng/mL × 1/mg) or slow (C/D ratio ≥ 1.05 ng/mL × 1/mg) metabolizers. TAC exposure/metabolism did not significantly correlate with interstitial fibrosis/tubular atrophy (IF/TA) progression during the first year after kidney transplantation. TAC CV third tertile was associated with a higher chronicity score at one-year biopsy. TAC C/D ratio at three months and Tac C0 at six months were associated with rejection during the first year after transplantation. A fast TAC metabolism at six months was associated with reduced kidney graft function one year (OR: 2.141, 95% CI: 1.044-4.389, p = 0.038) and two years after transplantation (OR: 4.654, 95% CI: 1.197-18.097, p = 0.026), and TAC CV was associated with reduced eGFR at three years. uNGAL correlated with IF/TA and chronicity scores at three months and negatively correlated with TAC C0 and C/D at three months and one year. Conclusion: Calculating the C/D ratio at three and six months after transplantation may help to identify patients at risk of suffering acute rejection and deterioration of graft function.

Sildenafil and furosemide nanoparticles as a novel pharmacological treatment for acute renal failure in rats

Hospitalized patients often develop acute renal failure (ARF), which causes severe morbidity and death. This research investigates the potential renoprotective benefits of sildenafil and furosemide in glycerol-induced ARF, and measures kidney function metrics in response to nanoparticle versions of these medications. Inducing ARF is commonly done by injecting 50% glycerol intramuscularly. Rats underwent a 24-h period of dehydration and starvation before slaughter for renal function testing. We investigated urine analysis, markers of oxidative stress, histology of kidney tissue, immunohistochemistry analysis of caspase-3 and interleukin-1 beta (IL-1 β), kidney injury molecule-1 (KIM-1), and neutrophil gelatinase–associated lipocalin (NGAL), which are specific indicators of kidney tissue damage. The results of our study showed that the combination of sildenafil and furosemide, using both traditional and nanoparticle formulations, had a greater protective effect on the kidneys compared to using either drug alone. The recovery of renal tissue indicators, serum markers, and urine markers, which are indicative of organ damage, provides evidence of improvement. This was also indicated by the reduction in KIM-1 and NGAL tubular expression. The immunohistochemistry tests showed that the combination therapy, especially with the nanoforms, greatly improved the damaged cellular changes in the kidneys, as shown by higher levels of caspase-3 and IL-1β. According to the findings, a glycerol-induced rat model demonstrates that sildenafil and furosemide, either alone or in combination, in conventional or nanoparticulate forms, improve ARF dysfunction. The synergistic nanoparticulate compositions show remarkable effectiveness. This observation highlights the possible therapeutic implications for ARF treatment.

Determinants of serious health outcome-free status in middle-aged and older people with dysglycaemia: Exploratory analysis of the ORIGIN trial.

To assess clinical and biochemical measurements that can identify people with dysglycaemia (i.e. diabetes or pre-diabetes) who remain free of serious outcomes during follow-up. We conducted exploratory analyses using data from the Outcomes Reduction with an Initial Glargine Intervention (ORIGIN) study to identify independent determinants of outcome-free status in 12 537 middle-aged and older adults with prediabetes and early type 2 diabetes from 40 countries. Serious outcome-free status was defined as the absence of major cardiovascular outcomes, kidney or retinal outcomes, peripheral artery disease, dementia, cancer, any hospitalization, or death during follow-up. In total, 3328 (26.6%) participants remained free of serious outcomes during a median follow-up of 6.2 years (IQR 5.8, 6.7). Independent clinical determinants of outcome-free status included younger age, female sex, non-White ethnicity, shorter diabetes duration, absence of previous cardiovascular disease, current or former smokers, higher grip strength, Mini-Mental State Examination score, and ankle-brachial index, lower body mass index and kidney disease index, and non-use of renin-angiotensin system drugs and beta-blockers. In a subset of 8401 people with baseline measurements of 238 biomarkers, growth differentiation factor 15, kidney injury molecule-1, N-terminal pro-brain natriuretic peptide, uromodulin, C-reactive protein, factor VII and ferritin were independent determinants. The combination of clinical determinants and biomarkers best identified participants who remained outcome-free (C-statistics 0.71, 95% confidence interval 0.70-0.73; net reclassification improvement 0.55, 95% confidence interval 0.48-0.58). A set of routinely measured clinical characteristics and seven protein biomarkers identify middle-aged and older people with prediabetes or early type 2 diabetes as least likely to experience serious outcomes during follow-up.