Renal Content Research Articles

Assessment of Neutrophil Gelatinase Associated Lipocalin in Children with Acute Gastroenteritis and Dehydration to Identify Early Signs of Acute Kidney Injury

Background: Gastroenteritis often correlates with acute kidney injury (AKI) in children who are hospitalized. The primary diagnostic test for acute kidney injury (AKI) in modern times is serum creatinine (SCr), which increases in the presence of AKI and is eliminated by glomerular filtration. SCr is an unsuitable biomarker for renal sickness because it lacks specificity and a slow response to disease severity or treatment changes. NGAL, or neutrophil gelatinase-associated lipocalin, is a molecular weight of 25 kDa protein and forms a covalent bond with neutrophil gelatinase. Elevations in NGAL levels due to kidney injury have important predictive value and may forecast the onset of acute kidney injury (AKI) 24-72 hours before an increase in diagnostic serum creatinine (SCr) values. Aim and objectives: This study aims to determine whether plasma NGAL concentrations in mild, moderate, or severe dehydrated acute gastroenteritis patients may indicate acute kidney damage (AKI). The research will investigate whether acute renal injury and plasma NGAL concentrations are connected. Patients and methods: The cross-sectional design was employed in this study and included 80 patients who attended the pediatric gastrointestinal clinic at Babylon Children's Hospital. Between November 2022 and June 2023, all patients had gastroenteritis symptoms accompanied by different dehydration levels. Results: Patients with severe dehydration had considerable higher level of NGAL than those with mild to moderate dehydration (p<0.001). There was a notable inverse relationship (p = 0.046) between the NGAL level and potassium but a considerable direct link (p<0.001) between the NGAL level and creatinine. However, no significant correlation was seen between the NGAL level and urea (p = 0.404 and 0.062, respectively). The confidence range for the area under the curve (AUC) is 0.940 to 0.981, with a confidence level of 95%. The p-value is less than 0.001. The sensitivity is 88%. An accuracy of 88.4% has been attained. The NGAL cut-off point is 3.9832. Conclusion: An analysis of plasma neutrophil gelatinase-associated lipocalin (NGAL) in individuals with gastroenteritis and varied degrees of dehydration indicated a clear and direct link between the two parameters. Specifically, when dehydration worsened, the average NGAL value increased

In laying hens, chronic heat stress-induced renal fibrosis is potentially promoted by indoxyl sulfate

Indoxyl sulfate (IS), a uremic toxin, is a harmful factor that damages kidneys. Chronic heat stress in laying hens causes renal injury; however, whether IS accumulation is involved in this injury remains unknown. We selected 20 Boris brown laying hens (27 weeks old) and randomly assigned them to two groups (n = 10), one group was exposed to chronic heat stress (32 °C for 4 weeks), whereas the other was maintained at 24 °C. Chronic heat exposure significantly increased plasma and renal IS concentrations (P < 0.05). Exposure to heat also increased renal expression of the aryl hydrocarbon receptor (AhR) and its target genes (CYP1A4 and CYP1B1). Furthermore, chronic heat exposure tended to increase the 2-thiobarbituric acid reactive substances content (P = 0.08) and significantly decreased the antioxidant capacity in the kidney, while increasing the transcription levels of nuclear factor κB and fibrosis-related genes (COLA1A1, αSMA, TGF-β, Smad3, and VCAM-1) and the area of renal fibrosis. Our results indicate that chronic heat exposure induces systemic and renal IS accumulation in laying hens. This accumulated IS may activate the AhR pathway and chronically disrupt the oxidative stress status and antioxidant activity, thus promoting renal fibrosis and dysfunction in laying hens.

Potential roles for eNOS and NrF₂ /HO-1 signaling in the ameliorative effect of lixisenatide on diabetes-induced kidney injury in rats and its amplification by ticagrelor co-administration.

Antioxidant and anti-inflammatory effects of lixisenatide (LX) and ticagrelor (TC) have been previously identified in type 2 diabetes mellitus (T2DM). Diabetic nephropathy is one of the major complications of T2DM. In the current study, we examined the potential protective effects of LX and TC on experimentally induced diabetic nephropathy in T2DM rats and their possible molecular mechanisms. To examine this possibility, rats were fed a high-fat diet (HFD) for 12 weeks, followed by a single injection of 35 mg/kg streptozotocin (STZ) to induce T2DM. 10 μg/kg LX and 25 mg/kg TC were given alone or in combination to T2DM rats for 4 weeks. The kidney examination of T2DM rats showed clear deterioration. T2DM rats exhibited significantly higher body weight, blood glucose, hemostatic model assessment for insulin resistance (HOMA-IR), blood urea nitrogen (BUN), serum creatinine, kidney reactive oxygen species (ROS), nuclear factor-κ B (NF-κ B), and transforming growth factor-β (TGF-β ), and significantly lower serum insulin, urine creatinine, creatinine clearance (CRCL), kidney superoxide dismutase (SOD), glutathione reduced (GSH), nuclear factor erythroid 2 (NrF₂ ), heme oxygenase-1 (HO-1), and endothelial nitric oxide synthase (eNOS) when compared to control rats. Single treatment with LX or TC showed obvious ameliorative effects on kidney complications in T2DM rats, with more ameliorative effects with the combined administration of both drugs. Conclusion: Our investigation found that both LX and TC could significantly ameliorate the development of diabetic nephropathy via stimulating NrF₂ /HO-1 antioxidant pathway in addition to increasing eNOS and decreasing NF-κ B renal tissue concentrations, and these effects were markedly augmented by their combined administration.

Dr. Manuel Martinez-Maldonado: A Pioneer in Renal Therapeutics and Mentor to a Generation of Minority Physician-Scientists.

Dr. Manuel Martinez-Maldonado is a distinguished Puerto Rican internist, nephrologist, physician-scientist, mentor, and prolific writer whose leadership in academic and clinical settings has significantly advanced the fields of nephrology, renal physiology and pharmacology, fluids and electrolyte metabolism, calcium metabolism, hypertension research, and medical education. His research on electrolyte imbalances has led to innovative hypercalcemia treatments, notably furosemide withIV fluid therapy. This is an approach that, combined with pharmacotherapy using calcitonin and bisphosphonates, became the standard practice for managing hypercalcemia until specific therapies became available. His nephrology research team and laboratory in the San Juan VA (Veterans Affairs) Medical Center and the Medical School of the University of Puerto Rico were internationally renowned. Throughout his career, he fostered a culture of mentorship while spearheading superb clinical teaching and research initiatives. His transformative tenures at several institutions, including Baylor College of Medicine; the University of Puerto Rico-Medical Sciences Campus; the VA medical centers in Atlanta, Houston, and San Juan; Emory University; Oregon Health Sciences University; Ponce School of Medicine; and the University of Louisville School of Medicine demonstrate his lasting contributions to medical science and education. His interdisciplinary approach, advocacy for kidney and clinical research, and contributions to understanding the renin-angiotensin system and the role of sodium-potassium-activated adenosine triphosphatase in renal concentration mechanisms illustrate his enduring impact on renal physiology and human health.

Hydrogen sulphide reduces renal ischemia-reperfusion injury by enhancing autophagy and reducing oxidative stress.

Renal ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury. Hydrogen sulphide (H2S) exerts a protective effect in renal IRI. The present study was carried out to investigate the effects of exogenous H2S on renal IRI by regulating autophagy in mice. Mice were randomly assigned to control, IRI and NaHS (an H2S donor, 28, 56 and 100 μmol/kg) groups. Renal IRI was induced by clamping the bilateral renal pedicles with non-traumatic arterial clamp for 45 min and then reperfused for 24 h. Mice were administered intraperitoneally with NaHS 20 min prior to renal ischemia. Sham group mice underwent the same procedures without clamping. Serum and kidney tissues were harvested 24 h after reperfusion for functional, histological, oxidative stress, and autophagic determination. Compared with the control group, the concentrations of serum creatinine (Scr), blood urea nitrogen (BUN), and malondialdehyde (MDA), the protein levels of LC3II/I, Beclin-1 and P62, as well as the number of autophagosomes were significantly increased, but the activity of superoxide dismutase (SOD) was decreased after renal IRI. NaHS pre-treatment dramatically attenuated renal IRI-induced renal dysfunction, histological changes, MDA concentration and p62 expression in a dose-dependent manner. However, NaHS increased the SOD activity and the protein levels of LC3II/I and Beclin-1. These results indicate that exogenous H2S protects the kidney from IRI through enhancement of autophagy and reduction of oxidative stress. Novel H2S donors could be developed in the treatment of renal IRI.

Oral curcumin ameliorates acute murine campylobacteriosis

IntroductionHuman infections with the food-borne enteropathogen Campylobacter jejuni are responsible for increasing incidences of acute campylobacteriosis cases worldwide. Since antibiotic treatment is usually not indicated and the severity of the enteritis directly correlates with the risk of developing serious autoimmune disease later-on, novel antibiotics-independent intervention strategies with non-toxic compounds to ameliorate and even prevent campylobacteriosis are utmost wanted. Given its known pleiotropic health-promoting properties, curcumin constitutes such a promising candidate molecule. In our actual preclinical placebo-controlled intervention trial, we tested the anti-microbial and anti-inflammatory effects of oral curcumin pretreatment during acute experimental campylobacteriosis.MethodsTherefore, secondary abiotic IL-10-/- mice were challenged with synthetic curcumin via the drinking water starting a week prior oral C. jejuni infection. To assess anti-pathogenic, clinical, immune-modulatory, and functional effects of curcumin prophylaxis, gastrointestinal C. jejuni bacteria were cultured, clinical signs and colonic histopathological changes quantitated, pro-inflammatory immune cell responses determined by in situ immunohistochemistry and intestinal, extra-intestinal and systemic pro-inflammatory mediator measurements, and finally, intestinal epithelial barrier function tested by electrophysiological resistance analysis of colonic ex vivo biopsies in the Ussing chamber.Results and discussionWhereas placebo counterparts were suffering from severe enterocolitis characterized by wasting symptoms and bloody diarrhea on day 6 post-infection, curcumin pretreated mice, however, were clinically far less compromised and displayed less severe microscopic inflammatory sequelae such as histopathological changes and epithelial cell apoptosis in the colon. In addition, curcumin pretreatment could mitigate pro-inflammatory innate and adaptive immune responses in the intestinal tract and importantly, rescue colonic epithelial barrier integrity upon C. jejuni infection. Remarkably, the disease-mitigating effects of exogenous curcumin was also observed in organs beyond the infected intestines and strikingly, even systemically given basal hepatic, renal, and serum concentrations of pro-inflammatory mediators measured in curcumin pretreated mice on day 6 post-infection. In conclusion, the anti-Campylobacter and disease-mitigating including anti-inflammatory effects upon oral curcumin application observed here highlight the polyphenolic compound as a promising antibiotics-independent option for the prevention from severe acute campylobacteriosis and its potential post-infectious complications.

Lactate and hydrogen ions play a predominant role in evoking the exercise pressor reflex during ischaemic contractions but not during freely perfused contractions.

We investigated the role played by lactate and hydrogen in evoking the exercise pressor reflex (EPR) in decerebrated rats whose hindlimb muscles were either freely perfused or ischaemic. Production of lactate and hydrogen by the contracting hindlimb muscles was manipulated by knocking out the myophosphorylase gene (pygm). In knockout rats (pygm-/-; n=13) or wild-type rats (pygm+/+; n=13), the EPR was evoked by isometrically contracting the triceps surae muscles. Blood pressure, tension, blood flow, renal sympathetic nerve activity and blood lactate concentrations were measured. Intramuscular metabolites and pH changes induced by the contractions were quantified by 31P-magnetic resonance spectroscopy (n=5). In a subset of pygm-/- rats (n=5), contractions were evoked with prior infusion of lactate (pH 6.0) in an attempt to restore the effect of lactate and hydrogen ions. Contraction of freely perfused muscles increased blood lactate and decreased muscle pH in pygm+/+ rats only. Despite these differences, the reflex pressor and sympathetic responses to freely perfused contraction did not differ between groups (P=0.992). During ischaemia, contraction increased muscle lactate and hydrogen ion production in pygm+/+ rats (P<0.0134), whereas it had no effect in pygm-/- rats (P>0.783). Likewise, ischaemia exaggerated the reflex pressor, and sympathetic responses to contraction in pygm+/+ but not in pygm-/- rats. This exaggeration was restored when a solution of lactate (pH 6.0) was infused prior to the contraction in pygm-/- rats. We conclude that lactate and hydrogen accumulation in contracting myocytes play a key role in evoking the metabolic component of the EPR during ischaemic but not during freely perfused contractions. KEY POINTS: Conflicting results exist about the role played by lactate and hydrogen ions in evoking the exercise pressor reflex. Using CRISP-Cas9, we rendered the myophosphorylase gene non-functional to block the production of lactate and hydrogen ions. The exercise pressor reflex was evoked in decerebrated rats by statically contracting the triceps surae muscles with or without muscle ischaemia. Static contraction elevated the concentration of lactate and hydrogen ions in pygm+/+ but not in pygm-/- rats. Despite these differences, the exercise pressor reflex was not different between groups. Acute muscle ischaemia exaggerated the concentration of lactate and hydrogen ions in pygm+/+ but not in pygm-/- rats. Likewise, acute muscle ischaemia exaggerated the exercise pressor reflex in pygm+/+ but not in pygm-/- rats. We conclude that lactate and hydrogen play a key role in evoking the exercise pressor reflex during ischaemic but not during freely perfused contractions.

Consumption of sucrose in maternal and postnatal stages leads to kidney affectation in adult male rats

High sugar-sweetened beverage intake has been related to human kidney disease and metabolic alterations. We determine the impact of high sucrose intake from pregnancy until early postnatal days and post-weaning on kidneys from adult male offspring rats. Wistar female rats were mated and assigned into two groups: one control drinking tap water (CM) and another drinking 5 % sucrose diluted in water (SM). Two offspring per mother were randomly allocated into two experimental groups at weaning. One had free access to simple water (CO) and the other to 5 % sucrose (SO) for 14 weeks. After treatment, levels of relative aquaporin-2 (AQP2), glomerulosclerosis index (GI), collecting tube area, perirenal fat, blood creatinine, and blood ureic nitrogen concentration (BUN) were determined. Two-way ANOVA followed by Bonferroni post-hoc test was used, considering P ≤ 0.05 as a significant statistical difference. Sucrose consumption during gestation/lactation and interaction increased AQP2 expression in the renal cortex and BUN concentration. In contrast, gestation/lactation consumption increased collecting tube area, post-weaning consumption favored perirenal fat, and finally, gestation/lactation, post-weaning, and the interaction caused glomerulosclerosis. Our results suggest that the consumption of sucrose water during gestation/lactation or post-weaning or combination triggers pathological changes in the kidneys of adult rats.

Harmine alleviated STZ-induced rat diabetic nephropathy: A potential role via regulating AMPK/Nrf2 pathway and deactivating ataxia-telangiectasia mutated (ATM) signaling

Diabetic nephropathy (DN) is a serious kidney disorder driven by diabetes and affects people all over the world. One of the mechanisms promoting NF-κB-induced renal inflammation and injury has been theorized to be ATM signaling. On the other hand, AMPK, which can be activated by the naturally occurring alkaloid harmine (HAR), has been proposed to stop that action. As a result, the goal of this study was to evaluate the therapeutic effectiveness of HAR against streptozotocin (STZ)-induced DN in rats through AMPK-mediated inactivation of ATM pathways. Twenty male Wistar rats were grouped into 4 groups, as follow: CONT, DN, HAR (10 mg/kg), DN + HAR, where HAR was daily administered I.P. once for 2 weeks. The renal AMPK and PGC-1α expressions, as well as Sirt1 levels, were assessed. To ascertain the oxidative reactions, renal Nrf2 expression, HO-1, MDA, and TAC concentrations were measured. As parts of ATM pathways, ATM and p53 expressions, in addition to GSK-3β levels were determined. Renal expression of NEMO, TNF-α, and IL-6 levels were also estimated. Moreover, histopathological and immunohistochemical detection of Bcl-2, Bax, and caspase 3 were reported. Results indicated that HAR intake notably alleviated STZ-induced kidney damage by triggering AMPK and Sirt1, which in turn boosted PGC-1α, improved NRf2/HO-1 axis, and lowered ROS production. As a consequence, HAR blocked the ATM-triggered renal inflammation and minimized caspase-3 expression by repressing the Bax/Bcl2 ratio. Because of its ability to activate AMPK/Nrf2 axis, HAR may represent an emerging avenue for future DN therapy by blocking ATM pathways.

Regulation of renal aquaporin water channels in acute pyelonephritis.

Acute pyelonephritis (APN) is most frequently caused by uropathogenic Escherichia coli (UPEC), which ascends from the bladder to the kidneys during a urinary tract infection. Patients with APN have been reported to have reduced renal concentration capacity under challenged conditions, polyuria, and increased aquaporin-2 (AQP2) excretion in the urine. We have recently shown increased AQP2 accumulation in the plasma membrane in cell cultures exposed to E. coli lysates and in the apical plasma membrane of inner medullary collecting ducts in a 5-day APN mouse model. This study aimed to investigate if AQP2 expression in host cells increases UPEC infection efficiency and to identify specific bacterial components that mediate AQP2 plasma membrane insertion. As the transepithelial water permeability in the collecting duct is codetermined by AQP3 and AQP4, we also investigated whether AQP3 and AQP4 localization is altered in the APN mouse model. We show that AQP2 expression does not increase UPEC infection efficiency and that AQP2 was targeted to the plasma membrane in AQP2-expressing cells in response to the two pathogen-associated molecular patterns (PAMPs), lipopolysaccharide and peptidoglycan. In contrast to AQP2, the subcellular localizations of AQP1, AQP3, and AQP4 were unaffected both in lysate-incubated cell cultures and in the APN mouse model. Our finding demonstrated that cellular exposure to lipopolysaccharide and peptidoglycan can trigger the insertion of AQP2 in the plasma membrane revealing a new regulatory pathway for AQP2 plasma membrane translocation, which may potentially be exploited in intervention strategies.NEW & NOTEWORTHY Acute pyelonephritis (APN) is associated with reduced renal concentration capacity and increased aquaporin-2 (AQP2) excretion. Uropathogenic Escherichia coli (UPEC) mediates changes in the subcellular localization of AQP2 and we show that in vitro, these changes could be elicited by two pathogen-associated molecular patterns (PAMPs), namely, lipopolysaccharide and peptidoglycan. UPEC infection was unaltered by AQP2 expression and the other renal AQPs (AQP1, AQP3, and AQP4) were unaltered in APN.

Galectin-3 and Autophagy in Renal Acute Tubular Necrosis.

Acute kidney injury (AKI) is a public health burden with increasing morbidity and mortality rates and health care costs. Acute tubular necrosis (ATN) is the most common cause of AKI. Cisplatin (CIS) is a platinum-based chemotherapeutic agent used in the treatment of a wide variety of malignancies such as lung, breast, ovary, testis, bladder, cervix, and head and neck cancers. Autophagy plays an important role in AKI. Galectin-3 (Gal-3) is significantly increased in renal tubules in AKI; however, its role in autophagy is not well understood. Male C57B6/J and B6.Cg-Lgals3 <tm 1 Poi>/J Gal-3 knockout (KO) mice were used to induce AKI using a CIS mouse model of ATN. Renal Gal-3 and autophagy proteins' expression were measured using standard histologic, immunofluorescent, and enzyme-linked immunosorbent assay techniques. The data were presented as the mean ± S.E. Statistically significant differences (p < 0.05) were calculated between experimental groups and corresponding control groups by one-way analysis of variance. There was a significant increase in renal concentrations of Gal-3 in the Gal-3 wild-type CIS-treated mice when compared with sham control mice. There were significantly higher concentrations of renal LC3B, ATG13, Ulk-1, Beclin, ATG5, ATG12, ATG9A, and p-AMPK in the CIS-treated Gal-3 KO mice than in the Gal-3 wild-type CIS-treated mice. Further, there were significantly higher concentrations of mTOR, p- NF-κB, beta-catenin, and p62 in the kidneys of the Gal-3 wild-type CIS-treated mice than in the Gal-3 KO CIS-treated mice. Our findings affirm the connection between Gal-3 and autophagy, revealing its central role as a connector with prosurvival signaling proteins. Gal-3 plays a pivotal role in orchestrating cellular responses by interacting with prosurvival signal pathways and engaging with autophagy proteins. Notably, our observations highlight that the absence of Gal-3 can enhance autophagy in CIS-induced ATN.

Sleeve gastrectomy links the attenuation of diabetic kidney disease to the inhibition of renal tubular ferroptosis through down-regulating TGF-β1/Smad3 signaling pathway

PurposeTo investigate how sleeve gastrectomy (SG), a typical operation of bariatric surgery, attenuated symptom, and progression of diabetic kidney disease (DKD).MethodsDKD model was induced by high-fat diet (HFD) combined with streptozocin in Wistar rats. SG was performed, and the group subjected to sham surgery served as control. The animals were euthanized 12 weeks after surgery, followed by sample collection for the subsequent experiment. The HK-2, a renal proximal tubular epithelial cell line derived from human, was utilized to investigate the potential mechanisms.ResultsSG improved metabolic parameters and glucose homeostasis, and could alleviate DKD in terms of renal function indices as well as histological and morphological structures in DM rats, accompanied with a significant reduction in renal tubular injury. Compared with sham group, SG reduced the renal tubular ferroptosis. To further clarify the mechanism involved, in vitro experiments were performed. In the presence of high glucose, renal tubular TGF-β1 secretion was significantly increased in HK-2 cell line, which led to activation of ferroptosis through TGF-β1/Smad3 signaling pathway. Inhibition of TGF-β1 receptor and phosphorylation of Smad3 significantly ameliorated TGF-β1-mediated ferroptosis. In vivo experiments also found that SG improved the hyperglycemic environment, reduced renal TGF-β1 concentrations, and down-regulated the TGF-β1/Smad3 signaling pathway.ConclusionsWith the capacity to lower the glucose, SG could attenuate the ferroptosis by inhibiting TGF-β1/Smad3 signaling pathway in DKD rats, and eventually attenuated DKD.

High-energy SR-XRF Imaging of Cesium and Trace Elements in Mouse Kidneys: Short Communication.

For understanding trace element dynamics in tissues, methods for analyzing elemental distribution and localization without destroying tissue structures and cell arrangements are desired. Synchrotron radiation X-ray fluorescence (SR-XRF) analysis is one of the non-destructive and multi-element simultaneous analyses. The kidney is the major excretion pathway of cesium (Cs) taken into the body, and an understanding of cesium distribution in the kidney would be useful for establishing technology to facilitate the excretion of radioactive Cs from the body due to nuclear disasters. In the present study, the distribution of cesium and trace elements, such as iron (Fe) and zinc (Zn), corresponding to the kidney structure was examined in Cs-administered mice by SR-XRF imaging with high-energy excitation X-rays (40keV). By beam scanning with a 200-µm square beam, clear Cs images corresponding to the renal layer structure were obtained for the renal specimen at the early phase after Cs administration with the mean renal Cs concentration of 24.1 ± 3.2μg/g. Cs was distributed mainly in the medulla and the outer stripe of the outer medulla located in the center area of the kidney. Unlike the Cs distribution, endogenous Fe and Zn tended to be lower in the medulla than in the outer stripe of the outer medulla and the cortex. This method is effective for analyzing Cs distribution because it can simultaneously analyze the distribution of endogenous trace elements.

The protective effects of Vitamin D against Cadmium-induced nephrotoxicity

BackgroundCadmium (Cd) is retained in the kidneys in large amounts thus inducing oxidative damage. Vitamin D (VD) is a potent antioxidant that is postulated to reverse the Cd-induced oxidative effects. AimThe present study aimed at investigating the effect of VD administration on reversing Cd-induced renal toxicity. Material and methodsTwenty-four male rats were assorted into three equal groups: Negative control (NC) group receiving drinking water only, Positive control (PC) group receiving Cadmium chloride (CdCl2) and VD group receiving VD injections in addition to CdCl2. The serum levels of creatinine, urea and 25-OH VD as well as renal tissue concentration of glutathione peroxidase (GPX) and malondialdehyde (MDA) were measured. Tissue sections were examined for signs of renal injury, immunostained for Vitamin D receptor (VDR), Cyp24a1 and Cyp27b1 and the apoptotic index was measured. ResultsCd administration resulted in higher serum levels of creatinine and urea as well as lower serum 25-OH VD level in addition to higher MDA and lower GPX renal concentration. VD supplementation showed improved renal functions, a remarkable improvement in the renal tissue with enhanced expression of VDR and Cyp27b1, lower Cyp24a1 expression and a lower apoptotic index. ConclusionVD administration can ameliorate Cd-induced nephrotoxicity.

Reassessment of the cadmium toxicological reference value for use in human health assessments of foods

The U.S. Food and Drug Administration (FDA) developed an oral toxicological reference value (TRV) for characterizing potential health concerns from dietary exposure to cadmium (Cd). The development of the TRV leveraged the FDA's previously published research including (1) a systematic review for adverse health effects associated with oral Cd exposure and (2) a human physiological based pharmacokinetic (PBPK) model adapted from Kjellstrom and Nordberg (1978) for use in reverse dosimetry applied to the U.S. population. Adverse effects of Cd on the bone and kidney are associated with similar points of departure (PODs) of approximately 0.50 μg Cd/g creatinine for females aged 50–60 based on available epidemiologic data. We also used the upper bound estimate of the renal cortical concentration (50 μg/g Cd) occurring in the U.S. population at 50 years of age as a POD. Based on the output from our reverse dosimetry PBPK Model, a range of 0.21–0.36 μg/kg bw/day was developed for the TRV. The animal data used for the animal TRV derivation (0.63–1.8 μg/kg bw/day) confirms biological plausibility for both the bone and kidney endpoints.

Phytochemical study and Protective Effect of Trigonella foenum-graecum (Fenugreek Seeds) Methanolic Extract Underlying the Mechanism of Action on Diabetic Nephropathy in Experimental Rats

Background: Advanced glycation end products (AGEs) buildup and hyperglycemia both contribute significantly to the onset of diabetic nephropathy. A plant with high flavonoid content, Fenugreek Seeds Extract (FSE), may be able to reduce the activity of oxidative stress in cells and tissues. The purpose of this study was to determine if Fenugreek Seeds Extract (FSE) could prevent kidney damage in diabetic rats caused by the production of AGEs in the renal glomerulus. Objective: The current study aimed to estimate phytochemical screening, in-vitro antioxidant activity, and nephron-protective effect of Trigonella foenum-graecum (Fenugreek Seeds) methanolic extract. Methods: We have demonstrated the phytochemical composition of extract of fenugreek seeds. The antioxidant activity of the extract was determined using DPPH assay. Total of thirty six albino wistar rats were used for diabetic nephropthic activity. Normal control rats and diabetic rats were given low doses of fenugreek seed extract (100 mg/kg), medium doses (200 mg/kg), and high doses (400 mg/kg) by oral gavage for 8 weeks before being put to sacrificed. Adiponectin, renal function markers, pro-inflammatory markers, antioxidative markers, and glucose concentration were all measured. Results: It has been found that FSE treatment significantly prevented in STZ-induced increases in urine production, urinary albumin excretion, and urine albumin-to-creatinine ratio and markedly attenuated STZ-induced renal damages. Levels of aspartate aminotransferase, alanine aminotransferase and serum creatinine, blood urea nitrogen and malondialdehyde of kidney tissue were lower in extract treated groups than in contrast agent treated group, but the decrease in serum MDA was significant in the group given FSE. Serum antioxidant capacity was higher in the FSE contrast agent group than in the contrast agent group. Kidney tissue anti-oxidant capacity was significantly higher in the group given FSE than the contrast agent group. Conclusion: This study demonstrated that an appropriate amount of FSE 200 mg/kg in rats, could prevent diabetic nephropathy by improving antioxidant status and inhibiting inflammation in renal tissue. FSE extract may be effective in treating high-glucose-induced nephropathy.

Physiologically based pharmacokinetic model combined with reverse dose method to study the nephrotoxic tolerance dose of tacrolimus.

Nephrotoxicity is the most common side effect that severely limits the clinical application of tacrolimus (TAC), an immunosuppressive agent used in kidney transplant patients. This study aimed to explore the tolerated dose of nephrotoxicity of TAC in individuals with different CYP3A5 genotypes and liver conditions. We established a human whole-body physiological pharmacokinetic (WB-PBPK) model and validated it using data from previous clinical studies. Following the injection of 1mg/kg TAC into the tail veins of male rats, we developed a rat PBPK model utilizing the drug concentration-time curve obtained by LC-MS/MS. Next, we converted the established rat PBPK model into the human kidney PBPK model. To establish renal concentrations, the BMCL5 of the in vitro CCK-8 toxicity response curve (drug concentration range: 2-80mol/L) was extrapolated. To further investigate the acceptable levels of nephrotoxicity for several distinct CYP3A5 genotypes and varied hepatic function populations, oral dosing regimens were extrapolated utilizing in vitro-in vivo extrapolation (IVIVE). The PBPK model indicated the tolerated doses of nephrotoxicity were 0.14-0.185mg/kg (CYP3A5 expressors) and 0.13-0.155mg/kg (CYP3A5 non-expressors) in normal healthy subjects and 0.07-0.09mg/kg (CYP3A5 expressors) and 0.06-0.08mg/kg (CYP3A5 non-expressors) in patients with mild hepatic insufficiency. Further, patients with moderate hepatic insufficiency tolerated doses of 0.045-0.06mg/kg (CYP3A5 expressors) and 0.04-0.05mg/kg (CYP3A5 non-expressors), while in patients with moderate hepatic insufficiency, doses of 0.028-0.04mg/kg (CYP3A5 expressors) and 0.022-0.03mg/kg (CYP3A5 non-expressors) were tolerated. Overall, our study highlights the combined usage of the PBPK model and the IVIVE approach as a valuable tool for predicting toxicity tolerated doses of a drug in a specific group.

Sotos Syndrome and Nephrocalcinosis, a Rare But Possible Association due to Impact on Contiguous Genes.

One-month old breastfeeding infant, full-term birth, with normal anthropometric measurements at birth is referred to Pediatric Nephrology due to a nephrocalcinosis. The patient presents dysmorphic features and heart disease. A metabolic study is conducted on blood and urine yielding results within normal parameters, except for renal concentration test and acidification test. At 6 months of age, patient presents overgrowth, which along with other clinical signs arouse suspicion of Sotos Syndrome. Molecular genetic testing detects heterozygous deletion in 5q35 between bands q35.2 and q35.3, affecting genes NSD1, SLC34A1 and FGFR4, which is compatible with this syndrome and with nephrocalcinosis as a rare association.

#5849 RENAL RENIN IS UPREGULATED BY THE COMBINATION TREATMENT OF EMPAGLIFLOZIN AND RAS BLOCKADE IN EXPERIMENTAL DIABETIC NEPHROPATHY

Abstract Background and Aims Sodium-glucose cotransporter 2 (SGLT2) inhibitors have proven to delay diabetic nephropathy (DN) progression on top of renin-angiotensin system (RAS) blockade. This protection is mainly attributed to improvement in renal hemodynamics, although direct effects on the kidney cannot be ruled out. The present study aimed to identify renal proteins differentially expressed between vehicle-treated diabetic mice and mice treated with empagliflozin, ramipril, or their combination, that could help explain the protective mechanisms of the drugs. Method Twelve weeks old diabetic db/db mice were given empagliflozin (10 mg/Kg/day), ramipril (8 mg/Kg/day), or the combination of both drugs during 8 weeks. Vehicle-treated db/db and db/m mice were used as controls. Serum glucose, blood pressure, GFR, and albuminuria were measured at baseline and at the end of the study. After 8 weeks, mice were euthanized, and the kidneys and serum were saved. A differential high-throughput proteomic analysis by mass spectrometry using isobaric tandem mass tags (TMT labelling) was performed in kidney cortex. Results Vehicle-treated db/db mice showed increased glycemia during the whole experiment, and empagliflozin reduced blood glucose. Ramipril treatment decreased blood pressure. Vehicle-treated diabetic mice also showed incipient DN with increased mesangial matrix and albuminuria compared to their non-diabetic littermates. All the treatments reduced mesangial matrix expansion and albuminuria. Only 13 proteins were differentially expressed (false discovery rate &amp;lt;5% and Log2FC ≥1 or ≤ −1) when comparing treated mice vs vehicle-treated db/db mice. The differentially expressed proteins were only identified between the mice treated with the combination of empagliflozin and ramipril and the vehicle-treated diabetic mice. Ramipril or empagliflozin alone did not produce significant changes in renal proteins. Kidney renin was evidently increased by the combination therapy with empagliflozin and ramipril, along with the tubular transporter scaffolding protein MAP17. The results were further validated through renin staining and renal renin concentration measurement. Renal renin concentration was increased by ramipril and further increased by the combination therapy with empagliflozin and ramipril when compared to vehicle-treated db/db mice (55 pg/μg (IQR:49–64), 94 pg/μg (IQR:71–102), and 112 pg/μg (IQR 104–116) in the groups treated with vehicle, ramipril and the combination of empagliflozin and ramipril respectively). However, renin serum concentration was similar between mice treated with ramipril and mice treated with the combination. Conclusion The combined therapy of empagliflozin with ramipril upregulated renin in the kidney of a diabetic mouse model. The increase in kidney renin suggests that other mechanisms different from RAS act in the regulation of glomerular hemodynamics and arteriolar tone. Moreover, the increased sodium delivery to the macula densa does not inhibit renal renin secretion.

Vitamin D and calcium co-therapy mitigates pre-established cadmium nephropathy by regulating renal calcium homeostatic molecules and improving anti-oxidative and anti-inflammatory activities in rat

BackgroundCadmium (Cd) is a major environmental pollutant and chronic toxicity could induce nephropathy by increasing renal oxidative stress and inflammation. Although vitamin D (VD) and calcium (Ca) prophylactic treatments attenuated Cd-induced cell injury, none of the prior studies measure their renoprotective effects against pre-established Cd-nephropathy. AimsTo measure the alleviating effects of VD and/or Ca single and dual therapies against pre-established nephrotoxicity induced by chronic Cd toxicity prior to treatment initiation. MethodsForty male adult rats were allocated into: negative controls (NC), positive controls (PC), Ca, VD and VC groups. The study lasted for eight weeks and all animals, except the NC, received CdCl2 in drinking water (44 mg/L) throughout the study. Ca (100 mg/kg) and/or VD (350 IU/kg) were given (five times/week) during the last four weeks to the designated groups. Subsequently, the expression of transforming growth factor-β (TGF-β1), inducible nitric oxide synthase (iNOS), neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), VD synthesising (Cyp27b1) and catabolizing (Cyp24a1) enzymes with VD receptor (VDR) and binding protein (VDBP) was measured in renal tissues. Similarly, renal expression of Ca voltage-dependent channels (CaV1.1/CaV3.1), store-operated channels (RyR1/ITPR1), and binding proteins (CAM/CAMKIIA/S100A1/S100B) were measured. Serum markers of renal function alongside several markers of oxidative stress (MDA/H2O2/GSH/GPx/CAT) and inflammation (IL-6/TNF-α/IL-10) together with renal cell apoptosis and expression of caspase-3 were also measured. ResultsThe PC group exhibited hypovitaminosis D, hypocalcaemia, hypercalciuria, proteinuria, reduced creatinine clearance, and increased renal apoptosis/necrosis with higher caspase-3 expression. Markers of renal tissue damage (TGF-β1/iNOS/NGAL/KIM-1), oxidative stress (MDA/H2O2), and inflammation (TNF-α/IL-1β/IL-6) increased, whilst the antioxidants (GSH/GPx/CAT) and IL-10 decreased, in the PC group. The PC renal tissues also showed abnormal expression of Cyp27b1, Cyp24a1, VDR, and VDBP, alongside Ca-membranous (CaV1.1/CaV3.1) and store-operated channels (RyR1/ITPR1) and cytosolic Ca-binding proteins (CAM/CAMKIIA/S100A1/S100B). Although VD was superior to Ca monotherapy, their combination revealed the best mitigation effects by attenuating serum and renal tissue Cd concentrations, inflammation and oxidative stress, alongside modulating the expression of VD/Ca-molecules. ConclusionsThis study is the first to show improved alleviations against Cd-nephropathy by co-supplementing VD and Ca, possibly by better regulation of Ca-dependent anti-oxidative and anti-inflammatory actions.