Altered Renal Function Research Articles

Preventive and healing effect of high dosing grape seed flour on CKD patients of various stages and aetiologies

ABSTRACT Introduction Chronic kidney disease (CKD) is a worldwide public health concern characterised by a progressive alteration of renal function, and obesity, diabetes and hypertension are major risk factors. Oxidative stress is commonly observed in CKD patients resulting from an imbalance between overproduction of reactive oxygen species (ROS) and impairment of defense mechanisms. Therefore, strategies that alleviate oxidative stress may have major clinical implications towards improving vascular health and reducing the burden of CKD. Also, CKD worsens the quality of life of patients, therefore it is fundamental to implement new therapeutic strategies aimed at slowing down its progression. Materials and methods This interventional study is a randomised placebo-controlled clinical trial consisting at the daily oral supplementation with high dosing grape seed flour (GSF ≈ 1 g/kg) for experimental (n = 30) or starch for placebo (n = 10) to patients suffering from CKD of various stages and aetiologies. Blood and urine samples were collected at baseline and after a six-month-long supplementation period to follow up the disease evolution through the determination of renal function biomarkers, as well as antioxidant, anti-inflammatory and blood parameters. Results Supplementation with high dosing GSF was safe and well tolerated during the entire period of investigation. GSF clearly improved the main renal function biomarkers as GFR, proteinuria, blood pressure, oxidative stress and inflammation as well as the overall patient welfare as indicated by several blood parameters. Conclusion Most importantly high dosing GSF specifically halted and even reversed the progression of diabetic nephropathy a major cause of CKD and end stage renal disease.

Effects of maternal fructose intake on the offspring's kidneys.

Fructose overload is associated with cardiovascular and metabolic disorders. During pregnancy, these alterations may affect the maternal environment and predispose offspring to diseases. Aims: To evaluate the renal morphology and function of offspring of dams that received fructose overload during pregnancy and lactation. Methods: Female Wistar rats were divided into the control (C) and fructose (F) groups. C received food and water ad libitum, and F received food and d-fructose solution (20%) ad libitum. The d-fructose offer started 1 week before mating and continued during pregnancy and lactation. The progeny were designated as control (C) or fructose (F); after weaning, half of the F received water to drink (FW), and half received d-fructose (FF). Blood pressure (BP) and renal function were evaluated. The expression of sodium transporters (NHE3-exchanger, NKCC2 and NCC-cotransporters, and ENaC channels) and markers of renal dysfunction, including ED1 (macrophage), eNOS, 8OHdG (oxidative stress), renin, and ACE 1 and 2, were evaluated. CEUA-UNIFESP: 2757270117. The FF group presented with reduced glomerular filtration rate and urinary osmolarity, increased BP, proteinuria, glomerular hypertrophy, macrophage infiltration, and increased expression of transporters (NHE3, NCC, and ENaC), 8OHdG, renin, and ACE1. The FW group did not show increased BP and renal functional alterations; however, it presented glomerular hypertrophy, macrophage infiltration, and increased expression of the transporters (NHE3, NKCC2, NCC, and ENaC), renin, and ACE1. These data suggest that fructose overload during fetal development alters renal development, resulting in the increased expression of renin, ACE1, and sodium transporters, thus predisposing to hypertension and renal dysfunction.

Heterozygous expression of Cre recombinase in podocytes has no impact on the anti-glomerular basement membrane glomerulonephritis model in C57BL/6J mice.

A recent article described a thickening of the glomerular basement membrane (GBM) along with changes in the expression of key components of the extracellular matrix in 6‐month‐old NPHS2‐Cre transgenic mice, which express the Cre recombinase specifically in podocytes. This transgenic line has been widely used to characterize the implication of candidate genes in glomerular diseases in younger mice. Using a different mouse strain (C57BL/6J) than the previous report (129S6/SvEvTac), we sought to characterize 3‐ and 6‐month‐old NPHS2‐Cre +/− mice in control and pathological conditions. At baseline, there was no difference in renal function and histology between control and NPHS2‐Cre +/− mice. Notably, GBM thickness evaluated by transmission electron microscopy was similar between the two groups. We then induced an immune‐mediated severe glomerular insult, the anti‐glomerular basement membrane glomerulonephritis model (anti‐GBM‐GN) in 3‐month‐old control and NPHS2‐Cre +/− mice. NPHS2‐Cre +/− mice exhibited the same alterations in renal function and structure as control mice. In summary, our study strongly suggests that NPHS2‐Cre +/− transgenic mice on a C57BL/6J background can be safely used for podocyte‐specific gene inactivation in control conditions and in the anti‐GBM‐GN model.

Impact of therapeutic drug monitoring of antibiotics in the management of infective endocarditis.

Treatment of infective endocarditis (IE) is based on high doses of antibiotics with a prolonged duration. Therapeutic drug monitoring (TDM) allows antibiotic prescription optimization and leads to a personalized medicine, but no study evaluates its interest in the management of IE. We conducted a retrospective, bicentric, descriptive study, from January 2007 to December 2019. We included patients cared for IE, defined according to Duke's criteria, for whom a TDM was requested. Clinical and microbiological data were collected after patients' charts review. We considered a trough or steady-state concentration target of 20 to 50mg/L. We included 322IE episodes, corresponding to 306 patients, with 78.6% (253/326) were considered definite according to Duke's criteria. Native valves were involved in 60.5% (185/306) with aortic valve in 46.6% (150/322) and mitral in 36.3% (117/322). Echocardiography was positive in 76.7% (247/322) of cases. After TDM, a dosage modification was performed in 51.5% (166/322) (decrease in 84.3% (140/166)). After initial dosage, 46.3% (82/177) and 92.8% (52/56) were considered overdosed, when amoxicillin and cloxacillin were used, respectively. The length of hospital stay was higher for patient overdosed (25days versus 20days (p = 0.04)), and altered creatinine clearance was associated with overdosage (p = 0.01). Our study suggests that the use of current guidelines probably leads to unnecessarily high concentrations in most patients. TDM benefits predominate in patients with altered renal function, but probably limit adverse effects related to overdosing in most patients.

SGLT2-inhibitors are effective and safe in the elderly: The SOLD study

Background and aimsSodium-glucose co-transporter-2 inhibitors (SGLT2i) may have important benefits for the elderly with type 2 diabetes (T2D), however some safety concerns still limit their use in patients over 70 years of age. The SOLD study (SGLT2i in Older Diabetic patients) is a multicenter study, aimed to evaluate the effectiveness and safety of SGLT2i in the older diabetic patients in a real-life setting. Materials and methodsWe analyzed a population of 739 adults (mean age 75.4 ± 3.9 years, M/F 420/319) with T2D, which started a SGLT2i-based treatment after the age of 70, with at least one year of follow-up. Data were collected at baseline, at 6 and 12 months of follow-up. ResultsSGLT2i (37.5% Empagliflozin, 35.7% Dapagliflozin, 26.1% Canagliflozin, 0.7% Ertugliflozin) were an add-on therapy to Metformin in 88.6%, to basal insulin in 36.1% and to other antidiabetic drugs in 29.6% of cases. 565 subjects completed the follow up, while 174 (23.5%) discontinued treatment due to adverse events which were SGLT2i related. A statistically significant reduction of glycated hemoglobin (baseline vs 12 months: 7.8 ± 1.1 vs 7.1 ± 0.8%, p < 0.001) and body mass index values (baseline vs 12 months: 29.2 ± 4.7 vs 28.1 ± 4.5 kg/m2, p < 0.001) were evident during follow-up. Overall, estimated glomerular filtration rate remained stable over time, with significant reduction of urinary albumin excretion. In the subgroup of patients which were ≥ 80 years, a significant improvement in glycated hemoglobin values without renal function alterations was evident. Overall discontinuation rate during the follow-up period was different across age groups, being urinary tract infections and worsening of renal function the most common cause. ConclusionSGLT2i are well-tolerated and safe in the elderly and appear as an effective therapeutic option, though some caution is also suggested, especially in more fragile subjects.

Preterm Birth, Kidney Function and Cardiovascular Disease in Children and Adolescents.

Over recent decades, there has been a global increase in preterm birth rate, which constitutes about 11% of total births worldwide. The present review aims to summarize the current knowledge on the long-term consequences of prematurity on renal and cardiovascular development and function. Recent literature supports that prematurity, intrauterine growth restriction or low birth weight (LBW) may have an adverse impact on the development of multiple organ systems, predisposing to chronic diseases in childhood and adulthood, such as arterial hypertension and chronic kidney disease. According to human autopsy and epidemiological studies, children born preterm have a lower nephron number, decreased kidney size and, in some cases, affected renal function. The origin of hypertension in children and adults born preterm seems to be multifactorial as a result of alterations in renal, cardiac and vascular development and function. The majority of the studies report increased systolic and diastolic blood pressure (BP) in individuals born preterm compared to full term. The early prevention and detection of chronic non-communicable diseases, which start from childhood and track until adulthood in children with a history of prematurity or LBW, are important.

Acute and sub-acute oral toxicity assessment of 5-hydroxy-1,4-naphthoquinone in mice

5-hydroxy-1,4-naphthoquinone (5NQ) or juglone is a bioactive molecule found in walnuts and has shown therapeutic effects in various disease models. Limited information is available regarding the toxicity of 5NQ, thereby limiting the clinical development of this drug. In the present study, oral acute (50, 300 and 2000 mg/kg) and sub-acute toxicity (5, 15 and 50 mg/kg) was assessed in mice to evaluate the safety of 5NQ. The acute toxicity study identified 118 mg/kg as the point-of-departure dose (POD) for single oral administration of 5NQ using benchmark dose modeling (BMD). Repeated administration of 5NQ at doses of 15 and 50 mg/kg/day caused reduction in food consumption and body weight of mice along with alterations in liver and renal function. Histopathological assessment revealed significant damage to hepatic and renal tissues at all doses in the acute toxicity study, and at higher doses of 15 and 50 mg/kg in the sub-acute toxicity study. We observed dose dependent mortality in sub-acute toxicity study and the no observed adverse effect level (NOAEL) was established as < 5 mg/kg/day. Modeling the survival response in sub-acute toxicity study identified 1.74 mg/kg/day as the POD for repeated administration of 5NQ. Serum levels of aspartate aminotransferase (AST) were most sensitive to 5NQ administration with a lower limit of BMD interval (BMDL) of 1.1 × 10−3 mg/kg/day. The benchmark doses reported in the study can be further used to determine a reference dose of 5NQ for human risk assessment.

Change of renal function after short-term use of cardioprotective agents in patients with type 2 diabetes is not accurately assessed by the change of estimated glomerular filtration rate: an observational study

BackgroundAfter initiating cardioprotective agents, a fall of estimated glomerular filtration rate (eGFR) has been reported in several studies. Our goal was to evaluate the accuracy of change of Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) eGFR in patients with type 2 diabetes (T2D) after short-term pharmacological intervention with angiotensin-converting enzyme inhibitor, angiotensin-receptor blocker, gliptin or sodium-glucose cotransporter-2 inhibitor.MethodsWe analyzed 190 patients with T2D in the early stage of the disease, having no overt renal impairment by CKD-EPI equation. In each patient, we measured GFR (mGFR) by applying the constant infusion input clearance technique with sinistrin (Inutest; Fresenius, Linz, Austria) at baseline and after short-term (4–12 weeks) pharmacological intervention with cardioprotective agents (ramipril, telmisartan, linagliptin, metformin, empagliflozin) that potentially lead to an alteration of renal function. Simultaneously, a standardized analysis of serum creatinine was performed and eGFR was estimated by the CKD-EPI equation.ResultsAverage mGFR was 111 ± 20 ml/min/1.73m2, whereas eGFR was lower with 93 ± 13 ml/min/1.73m2. The ratio eGFR/mGFR in relation to mGFR was almost curvilinear, showing an underestimation of renal function by eGFR in the upper normal range. At baseline only 80 patients (42%) lay within ± 10% of mGFR and the concordance correlation coefficient (CCC) was extremely low (− 0.07). After short-term pharmacological intervention changes in eGFR and mGFR correlated with each other (r = 0.286, p < 0.001). For example, for a given mGFR of 111 ml/min/1.73m2, a change of mGFR by ± 10% corresponded to ± 11 ml/min/1.73m2, but the confidence interval of eGFR was 25 ml/min/1.73m2. The CCC was low (0.22).ConclusionThe agreement between eGFR by CKD-EPI and mGFR is modest and the change of renal function after short-term pharmacological intervention is not accurately and precisely reflected by the change of eGFR in patients with T2D in the early stage of their disease.

Safety and Efficacy of Stereotactic Ablative Radiation Therapy for Renal Cell Cancer: 24-Month Results of the RSR1 Phase 1 Dose Escalation Study

PurposeStereotactic body radiation therapy (SBRT) has become a new therapeutic option for primary renal cell carcinoma. However, treatment doses lack consistency in the literature. The primary objective of this study was to determine the maximum tolerated dose for renal cancer SBRT. Methods and MaterialsThis phase 1 multicentric dose-escalation study assessed 4 dose levels: 8 Gy × 4, 8 Gy × 5, 10 Gy × 4, and 12 Gy × 4. The primary objective of this study was to determine the maximal tolerated dose, defined by the occurrence of dose-limiting toxicity was defined as any acute side effect of grade ≥4 based on the Common Terminology Criteria for Averse Events, version 4.0. ResultsFrom October 2010 to September 2017, 13 patients were enrolled. The median follow-up was 23 months. There was no dose-limiting toxicity in our study, and the highest dose was reached successfully. No acute or late toxic effects above grade 2 were seen. There was no significant alteration of renal function after treatment. At 24 months, 2 patients had partial response and the others had stable disease. ConclusionsAfter 24 months of follow-up, no dose-limiting toxicity was seen at any of the prescribed dose levels in our study. The findings suggest that our last dose level of 48 Gy in 4 12-Gy fractions can be considered safe and can be used in further studies.

Cytotoxicity, acute and sub-chronic toxicities of the fruit extract of Tetrapleura tetraptera (Schumm. & Thonn.) Taub. (Fabaceae)

BackgroundTetrapleura tetraptera is a medicinal spice traditionally used to treat cancer, diabetes, and several other ailments. This study analyzed the cytotoxicity of the dichloromethane methanol extract of T. tetraptera fruits (TTF) and its constituents. The toxicity profile of the TTF extract was also evaluated in rats.MethodsThe Cytotoxicity of this extract was evaluated using the resazurin reduction assay (RRA). Acute and sub-chronic toxicity studies were performed according to the protocol described by the Organisation for Economic Cooperation, and Development (OECD). Hematological, serum, and urine biochemical parameters, as well as histological sections of the liver and kidney, were also evaluated based on standard methods.ResultsThe TTF extract, compound 5, and the reference drug doxorubicin were active in all 9 tested cancer cell lines. The recorded IC50 ranged from 18.32 μM (against B16-F1 murine melanoma cells) to 36.18 μM (against SKMel-505 BRAF wildtype melanoma cells) for TTF, from 10.02 μM (towards MaMel-80a BRAF-V600E homozygous mutant melanoma cells) to 31.73 μM (against SKMel-28 BRAF-V600E homozygous mutant melanoma cells) for compound 5, and from 0.22 μM (against B16-F1 cells) to 9.39 μM (against SKMel-505 cells) for doxorubicin. The study of acute toxicity test showed that the lethal dose (LD50) of this extract was greater than 5000 mg/kg body weight. In the sub-chronic toxicity studies, variations were observed in some biochemical parameters, especially at higher doses.ConclusionTTF and its most active compound (5) are found to be potential cytotoxic agents, meanwhile, TTF was safe when given a single oral dose of 5000 mg/kg. However, caution is necessary in case of prolonged oral administration due to potential alterations of renal function at high doses (> 1000 mg/kg).

Reflux nephropathy and scarring nephropathy: So close and yet so different

ObjectivesReflux nephropathy is a radiologic condition commonly used to express the existence of renal morphological lesions in patients who have or had vesicoureteral reflux (VUR). This morphological concept is used based on the image data collected, without conducting basic complementary renal function studies. The present study was designed to demonstrate that patients with active VUR present different functional renal alterations from those shown by patients with disappeared VUR. MethodsLongitudinal descriptive retrospective analysis including 89 children (46M, 43F) with VUR diagnosis through a standard voiding cystourethrogram (VCUG). The basic renal function tests collected were the maximum urinary osmolality (UOsm) and the urinary albumin/creatinine and NAG/creatinine ratios. The data collected corresponded to two moments, when VUR was diagnosed and when it had already disappeared. ResultsQuantitative differences were verified in the three functional parameters when comparing those corresponding to both moments of the study. In the qualitative analysis, in relation to the intensity of the VUR, differences were observed in UOsm at diagnosis and in the albumin/creatinine ratio once the VUR had cured. At this last moment, a significant increase in the albumin/creatinine ratio was observed in patients with loss of renal parenchyma in relation to those without residual morphological lesions. ConclusionsConcentrating ability defect is the most frequent finding in children with active reflux (true reflux nephropathy), whereas the most frequent functional disturbance found, once VUR has cured, is an increase in urinary albumin excretion, related to parenchymal damage. The term dysplastic-scarring nephropathy, could be more appropriate for patients with residual morphological lesions and impaired renal function, once VUR is cured.

Pathophysiology and system biology of rat c-BSA induced immune complex glomerulonephritis and pathway comparison with human gene sequencing data

Immune-complex glomerulonephritis (ICGN) is a major cause of nephrotic syndrome in adults and children. Cationic BSA (c-BSA) intravenous injection could produce significant albuminuria within a short time, and is a suitable in vivo experimental animal model to investigate the pathophysiology of ICGN and for drug screening, but lack of thorough study to clarify its dynamic pathophysiological alteration so far, as well as detailed changes in mRNA and LncRNA levels. The purpose of this study is to investigate the dynamic alteration in renal function, lipid metabolism and histopathology during the progress of c-BSA induced ICGN. RNA sequencing was used to identified differentially expressed mRNA and LncRNA in kidney cortex of ICGN. Results demonstrated that c-BSA induced ICGN model could completely exhibit clinical features of immune-mediated nephrotic syndrome with gradual declining renal function, and increased albuminuria and deteriorated histopathological injuries. The correlation analysis suggested that complement activation was the most key element in mediating of ICGN. RNA sequencing using rat kidney tissues combined with Gene Expression Omnibus (GEO) data of human glomerulonephritis showed the most enriched KEGG pathways in ICGN were Toll-like receptor signaling pathway, B cell receptor and Focal adhesion. The differential lncRNAs in ICGN rats were also screened, and the lncRNA-mRNA co-expression network was constructed to clarify lncRNA role in molecular mechanism of ICGN progression. Their human homogenous lncRNAs were also identified, such as ST3GAL5-AS1 and DIO3OS, which provide the potential lncRNA targets to treat ICGN. All the differential LncRNAs in ICGN kidneys caused by MMF were also identified and provided another possible pharmacological mechanism of MMF through lncRNA regulation. In summary, the current study firstly described the dynamic physiological changes of c-BSA induced ICGN, identified most key KEGG pathways, and provided lncRNA-mRNA regulatory network in ICGN.

MO281: Development of an Experimental Model of Haemodynamic Frailty Predisposing to Acute Kidney Injury

Abstract BACKGROUND AND AIMS Frailty is a pre-morbid condition characterized by physiological decline and reduced physiological reserve leading to increased vulnerability to disease, especially common among older adults. Tissue and organ function is underpinned by effective haemodynamic regulation coping with everyday acute challenges and stressors. Impairment of the haemodynamic response may lead to tissue hypoperfusion and subsequent adverse events, such as acute kidney injury (AKI) and others. ‘Haemodynamic frailty’ defines a clinically silent condition characterized by a compromised haemodynamic reserve and impaired adaptive response to supervening circumstances (i.e. stressors such as drugs). Yet, frailty also offers a window of opportunity for disease prevention and health maintenance. Dehydration, hypertension and some drugs are important causes of haemodynamic frailty [1]. In this work, we aimed to develop a pre-clinical model of haemodynamic frailty, based on dehydration and hypertension, predisposing to AKI. METHOD Three-month old male spontaneously hypertensive (SHR) rats were divided into four groups: (1) Control (CT): rats with ad libitum access to drinking water, receiving saline solution (0.9% NaCl, i.p.). (2) Cisplatin (CDDP): rats with ad libitum access to drinking water, receiving a sub nephrotoxic dose of cisplatin (2.5 mg/kg, i.p.). (3) Water deprivation (WD): rats with no access to drinking water during 48 h, receiving saline solution (0.9% NaCl, i.p.). (4) Water deprivation + cisplatin (WD + CDDP): rats with no access to drinking water during the 48 h previous to the cisplatin administration (2.5 mg/kg, i.p.). The dose of cisplatin had proved to be sub-nephrotoxic for normal rats in our previous studies [2]. 24-hour urine and tail vein blood samples were collected at basal state (B), 2 days after water deprivation (D0), and 4 days after cisplatin administration (D4, day of maximum kidney damage). Urine samples were analysed for volume (urinary flow), specific gravity, osmolality, and proteinuria (Bradford method). Haematocrit was calculated from blood samples and plasma was used to determine osmolality, concentration of creatinine (Jaffe reaction) and urea (Jung method). RESULTS SHR rats with 48 hours of water deprivation showed a 10% weight loss, increases in haematocrit and plasma osmolality and a highly concentrated urine (with elevated levels of urine specific gravity and osmolality), which indicates a moderate to severe state of dehydration. No alterations in renal function were observed after water deprivation. Administration of cisplatin triggered significant increases in plasma creatinine, plasma urea and proteinuria, indicative of AKI, only in rats previously deprived of water for 48 h. All the parameters studied remained normal in cisplatin-treated rats without water restriction. Our results suggest that our experimental animal model, based on a combination of hypertension and dehydration, reproduces a state of haemodynamic frailty in which rats become predisposed to undergoing renal failure following exposure to stressors (e.g. a sub-nephrotoxic dose of cisplatin) that are harmless to haemodynamically competent rats. CONCLUSION To our knowledge, this is the first experimental model of haemodynamic frailty predisposing to AKI. This model will allow us to further study mechanisms and biomarkers useful for diagnosis and stratification of haemodynamic frailty in order to develop strategies to prevent undesired health outcomes, including renal damage.

MO116: Vitamin C Nephrotoxicity in a COVID-19 Patient: A Case Report

BACKGROUND AND AIMSDuring the time of the COVID-19 pandemic, multiple treatment options have been investigated, even though their efficacy and secondary effects remain insufficiently known.We report the case of a vitamin C induced oxalate nephropathy in a COVID-19 patient with preexisting chronic kidney disease (CKD) resulting in irreversible acute renal failure.Vitamin C, also known as ascorbic acid, has been used as an anti-inflammatory therapy for COVID-19, but review of the literature shows similar cases of acute kidney injury (AKI), raising concern.METHODWe report the case of a 73-year-old Caucasian woman admitted for hyperthermia and digestive disorders. She had recently started a first-line chemotherapy for multiple myeloma with partial response. She also displayed preexisting stage 4 CKD (eGFR 18.50 mL/min/1.73 m² using CKD-EPI) of unknown aetiology.She was tested positive for SARS-CoV2 by nasopharyngeal swab and soon transferred to the intensive care unit. She received intravenous corticosteroids using dexamethasone 6 g/24 h for 10 days and a piperacillin + tazobactam probabilistic antibiotherapy. She also received high doses (15 g/24 h) of vitamin C for three consecutive days. No monoclonal antibodies were prescribed due to a previous vaccination with a positive serology upon admission.Although the patient recovered from respiratory tract infection, her kidney function progressively deteriorated with serum creatinine levels rising up to 8.06 g/dL, leading to her admission in our nephrology department. The patient was initially treated with high doses of diuretics for anasarca and an abdominal CT excluded urinary tract obstruction with normal kidney size and aspect. Urinary analysis showed protein to creatinine (p/c) ratio of 1348 g/g, and presence of urinary light chains. Her monoclonal spike was measured at 2.3 g/L and her kappa/lambda fraction was 1.74.Intermittent haemodialysis was initiated, and a kidney biopsy was performed.RESULTSHistology revealed hundreds of intratubular calcium oxalate crystals, with severe and diffuse acute tubular necrosis and interstitial edema. There was no amyloidosis, no sign of active glomerular disease and no interstitial fibrosis. Immunofluorescence (IgA, IgG, IgM, C1Q, C3, kappa and lambda) was negative. We concluded to oxalate nephropathy.After a 2-month follow-up, the patient remains dialysis dependent.Vitamin C is a precursor of oxalate and has been shown to cause secondary oxaluria, particularly with high-dose regimens in patients with altered renal function. Given the histological findings evocative of acute oxalate nephropathy, the accountability of high doses of vitamin C should be considered.No other cause of hyperoxaluria was identified in our patient beside broad spectrum antibiotic use, which could decrease intestinal bacterial oxalate degradation. In particular, there was no malabsorptionThe limitation of our report is the unknown cause of preexisting CKD; therefore, we cannot rule out preexisting hyperoxaluria. Also, no dosage of serum vitamin C and oxalate levels were performed during follow-up. Finally, our patient had other possible causes AKI, such as recent SARS-CoV2 infection, or linked to multiple myeloma, but these were considered unlikely given the proper haematological response to treatment and non-evocative biopsy.The rationale for vitamin C use in COVID-19 is based on in vitro studies showing its antioxidant, anti-inflammatory, anticoagulant and immune modulatory properties. There lack large clinical studies, and the literature shows conflicting results. Multiple cases of acute oxalate nephropathy were described.CONCLUSIONVitamin C is an anti-inflammatory treatment used in COVID-19 that can lead to secondary hyperoxaluria with significant and irreversible AKI. Due to the severity of AKI in patients with preexisting CKD, we believe renal function should be considered before using high doses of vitamin C.Larger controlled trials are needed both to establish the clinical benefit of vitamin C and further describe its potential nephrotoxicity.

MO273: Water Restriction and Age Increase the Risk of Triple Whammy-Induced Acute Kidney Injury

Abstract BACKGROUND AND AIMS Hypertension has a high prevalence in adult population and represents an important cause of premature death worldwide. Its treatment often consists of the combination of several antihypertensive drugs, including angiotensin-converting-enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB) and diuretics. Hypertensive patients eventually receive analgesic treatments linked to other pathologies. The combination of antihypertensive treatments (ACEi/ARB and diuretics) with non-steroidal anti-inflammatory drugs (NSAIDs) may generate an acute kidney injury (AKI) due to a reduction in the glomerular filtration rate. According to different studies, the incidence of AKI following this triple therapy or Triple Whammy (TW) ranges from &amp;lt; 1% to up to 22%. This suggests that additional factors determine the renal impact of the TW. Because the incidence of TW-induced AKI is higher among older adults, and because the prevalence of dehydration is especially elevated among them, the aim of our study was to model in rats the influence of water restriction and ageing on the renal effect of the TW. METHOD Male Spontaneously Hypertensive Rats (SHR) of 3 and 7 months of age were divided in four experimental groups: control group (CT), control group with 60%–70% water restriction of basal intake (i.e. 15 mL/day) (CT-WR), TW group (TW), and TW group with 60%–70% water restriction of basal intake (i.e. 15 mL/day) (TW-WR). Both TW groups received antihypertensive treatment with Trandolapril in drinking water and Furosemide i.p. for 4 days, and then a triple therapy for 2 days with Trandolapril and Ibuprofen in drinking water and Furosemide i.p. Urine and blood samples were collected at basal state (B), after 4 days of the combined treatment of Trandolapril + Furosemide (day 4) and two days after adding ibuprofen treatment (day 6). Blood pressure was measured on B and day 4, and the kidneys were removed at the end of the experiment. We analyzed the hydration status (water balance), the renal function (plasma creatinine and urea determination) and renal histological alterations (hematoxylin–eosin staining). RESULTS Antihypertensive treatment decreased systolic blood pressure in the TW and TW-WR groups, and did not induce any effects in CT and CT-WR groups. Water balance was lower in CT-WR, TW and TW-WR groups than in CT group, which may indicate partial dehydration, being this balance negative in TW-WR group. No differences in creatinine and plasma urea levels were found on day 6 between 3- and 7-months-old rats in TW group. An experimental AKI was observed in rats treated with TW and water restriction, characterized by increased creatinine and plasma urea; this experimental AKI was more severe in 7-month-old rats. CT and CT-WR groups showed normal renal function. There were no histological alterations in any of the experimental groups. CONCLUSION Water restriction is an important risk factor in the development of AKI in TW therapy, and although age differences do not have a relevant effect on their own, the combination of age and water restriction increases the risk.

Inhibition of Na+/H+ exchanger‐3 (NHE3) results in hyperphosphatemia without major alterations in Ca2+ homeostasis

Pharmacological and genetic inhibition of renal Na+/H+ exchanger‐3 (NHE3) may lower blood pressure in hypertensive mouse models, but potential side effects are not well‐characterized. NHE3 is proposed to play a major role in renal Ca2+ reabsorption, which is regulated by the parathyroid hormone (PTH). Furthermore, PTH also regulates phosphate (Pi) balance. Therefore, the aims of this study were to examine the effects of NHE3 inhibition on Pi and Ca2+ homeostasis. Mice with NHE3 deletion in the kidney tubule (NHE3loxloxPax8) were used to assess chronic effects, whereas mice administered the NHE3 inhibitor S3226 were used to examine acute effects. NHE3loxloxPax8 mice had increased plasma Pi and PTH levels that coincided with reduced abundances of the Na+‐Pi cotransporters (NaPi) ‐2a and ‐2c, but urinary Pi excretion was normal. Feeding mice a low Pi diet reduced PTH and increased both NaPi‐2a and ‐2c protein abundances in NHE3loxloxPax8 and control mice, but NaPi‐2c levels remained lower in NHE3loxloxPax8 mice. NHE3loxloxPax8mice were normocalcemic with normal urinary Ca2+ excretion, but had greater furosemide‐induced calciuresis, suggesting increased Na+‐K+‐Cl‐ cotransporter (NKCC2) activity. NHE3loxloxPax8 mice had reduced calciuresis subsequent to a thiazide diuretic. Treatment of wild‐type mice with the NHE3 inhibitor S3226 reduced creatinine clearance, increased plasma Pi and fibroblast growth factor 23 (FGF‐23) and reduced the abundances of NaPi‐2a and ‐2c. Plasma Ca2+ was not significantly altered by S3226 whereas urine Ca2+ excretion was transiently reduced. Collectively, inhibition of NHE3 results in hyperphosphatemia without major alterations in Ca2+ homeostasis. Data suggest that NHE3 inhibitors may constitute significant health risks due to alterations in renal function and Pi homeostasis.

Optimal Dose of Cefoperazone-Sulbactam for Acute Bacterial Infection in Patients with Chronic Kidney Disease.

The optimal dosage of cefoperazone-sulbactam for patients with chronic kidney disease (CKD) remains unclear. This study aimed to investigate two treatment strategies of cefoperazone-sulbactam–2 g/2 g twice daily and adjusted dose according to renal function for patients with CKD. A total of 155 patients with CKD received cefoperazone-sulbactam either at a dose of 2 g/2 g twice daily (study group) or adjusted according to renal function (control group) for the treatment of acute bacterial infection. The primary outcome was the clinical response rate at day 14 and the secondary outcomes included treatment failure and all-cause death. The study group had a higher clinical response rate (80.0% vs. 65.0%) and a lower treatment failure rate (4.0% vs. 23.8%) as compared with the control group. Further multivariable analysis showed that compared with the control group, the study group had a higher clinical response rate (adjusted OR = 4.02; 95% CI, 1.49–10.81) and lower treatment failure rate (adjusted OR = 0.06; 95% CI, 0.01–0.28). In addition, no significant difference in all-cause mortality was observed between the study and the control group (adjusted OR = 1.95; 95% CI, 0.57–6.66). Finally, no significant difference was observed between the study and the control group in the risk of the adverse events (AEs)–diarrhea (p = 0.326), eosinophilia (p = 1.000), prolonged PT (p = 0.674), alteration in renal function (p = 0.938) and leukopenia (n = 0.938). In conclusion, cefoperazone-sulbactam at a dose of 2 g/2 g twice daily could achieve better clinical efficacy than the reduced dosage regimen. Additionally, this dosage did not increase the risk of AE compared to the reduced dose. Therefore, cefoperazone-sulbactam at a dose of 2 g/2 g twice daily is an effective and safe regimen for acute bacterial infection in patients with CKD.

Early Biomarkers of Altered Renal Function and Orthostatic Intolerance During 10-day Bedrest.

Exposure to actual or simulated microgravity results in alterations of renal function, fluid redistribution, and bone loss, which is coupled to a rise of urinary calcium excretion. We provided evidence that high calcium delivery to the collecting duct reduces local Aquaporin 2 (AQP2)-mediated water reabsorption under vasopressin action, thus limiting the maximal urinary concentration to reduce calcium saturation. To investigate early renal adaptation into simulated microgravity, we investigated the effects of 10 days of strict bedrest in 10 healthy volunteers. We report here that 10 days of inactivity are associated with a transient, significant decrease (day 5) in vasopressin (copeptin) paralleled by a decrease in AQP2 excretion, consistent with an increased central volume to the heart, resulting in reduced water reabsorption. Moreover, bedrest caused a significant increase in calciuria secondary to bone demineralization paralleled by a decrease in PTH. Urinary osteopontin, a glycoprotein exerting a protective effect on stone formation, was significantly reduced during bedrest. Moreover, a significant increase in adrenomedullin (day 5), a peptide with vasodepressor properties, was observed at day 5, which may contribute to the known reduced orthostatic capacity post-bedrest. We conclude that renal function is altered in simulated microgravity and is associated with an early increase in the risk of stone formation and reduced orthostatic capacity post-bedrest within a few days of inactivity.

A rat model of acute kidney injury caused by multiple subcutaneous injections of Asian giant hornet (Vespa mandarina Smith) venom

A model of acute kidney injury (AKI) caused by multiple subcutaneous injections of Asian giant hornet (Vespa mandarina Smith) venom was developed in male Wistar rats. The rats were injected subcutaneously at multiple sites in the dorsal region with a total venom dose of 5 mg/kg. Blood samples were obtained 8, 24 and 48 h after venom injection for the quantification of various biochemical parameters and assessment of renal function. Wasp venom caused significant increases in all biochemical parameters (aspartate aminotransferase, creatine kinase, free hemoglobin, lactate dehydrogenase, myoglobin, and plasma creatinine) within 8 h of venom administration, as well as marked alterations in renal function (a decrease in glomerular filtration rate leading to oliguria). The biochemical parameters showed varying degrees of recovery but remained elevated to varying degrees after 48 h, whereas the glomerular filtration rate showed no recovery during this period. The histopathological alterations consisted primarily of acute tubular necrosis, with tubular epithelial cell sloughing and loss of tubule brush border. This profile of biochemical and functional alterations was similar to that seen in human envenomations by this species, suggesting that this animal model may be useful for understanding the pathophysiology of AKI caused by this wasp venom.

Role of prognostic scores in the evolution of renal involvement in patients with multiple myeloma after bone marrow transplantation

Introduction: Treatment of multiple myeloma (MM) with chemotherapy and autologous bone marrow transplantation (BMT) commonly results in renal dysfunction associated with early mortality. Prognostic scores for MM are assessed by either Durie and Salmon (DS) or International Staging System (ISS) methods. Few studies have examined the relationship between these scores and renal damage after BMT. Aims: To evaluate DS and ISS prognostic scores as they relate to renal function and mortality in MM patients who have undergone BMT. Methods: Retrospective, observational cohort of 95 MM patients who underwent BMT between 2012 and 2014. Renal function was assessed using data on proteinuria, serum creatinine, and estimated glomerular filtration rate from the time of hospital admission to 6 months post-BMT. Results: Neither score was significantly associated with death or proteinuria, but patients in DS stage IIIB were 12.8 times more likely to experience renal dysfunction than those in DS stage I–II. Both DS and ISS scores reflected a progressive increase in the chance of renal functional impairment with increased disease staging. Conclusions: The prognostic methods studied were useful in the initial recognition of renal dysfunction and after 6 months post BMT, the DS score was still able to predict the reduction of eGFR. Patients in the advanced stages of MM were associated with altered renal function, and these results could help to establish early treatment strategies to reduce the risk of renal damage.