Renal Filtration Research Articles

Perfluorooctanoic acid (PFOA) exposure induces renal filtration and reabsorption disorders via down-regulation of aquaporins

Perfluorooctanoic acid (PFOA) exposure is associated with kidney dysfunction, however the exact mechanisms by which PFOA induces nephrotoxicity and the specific involvement of aquaporins (AQPs) in kidney tissue remains unclear. In this study, adult male Sprague-Dawley (SD) rats were exposed to PFOA by oral gavage for 28 days and compared with controls. Body weight, water intake and urine volume were recorded daily. At the end of the experiment, blood and kidney samples were collected, and serum urea, creatine and uric acid levels were assessed. The renal expression levels of water channel proteins AQP1, AQP3, AQP2 and p-AQP2 (Ser256) were observed by immunohistochemical staining, and the corresponding transcription levels were detected by Western blot and qRT-PCR. The results showed that PFOA exposure inhibited weight gain and increased water intake, urine volume, kidney weight and renal visceral index. PASM staining and transmission electron microscopy revealed pathological thickening of the glomerular capsule and basement membrane. Serum urea levels were increased, while serum creatine levels were decreased compared to controls. Additionally, the expression levels of AQP1, AQP3, AQP2 and p-AQP2 in kidney tissues were decreased, and the phosphorylation of AQP2 at Ser256 was inhibited. In conclusion, we demonstrate that PFOA exposure can damage the renal filtration barrier and reduce the expression level of AQPs in renal tissues, leading to renal filtration and reabsorption disorders.

The GLP-1-mediated gut-kidney cross talk in humans: mechanistic insight.

Incretin-based therapy is an antidiabetic and antiobesity approach mimicking glucagon-like peptide-1 (GLP-1) with additional end-organ protection. This review solely focuses on randomized, controlled mechanistic human studies, investigating the renal effects of GLP-1. There is no consensus about the localization of GLP-1 receptors (GLP-1Rs) in human kidneys. Rodent and primate data suggest GLP-1R distribution in smooth muscle cells in the preglomerular vasculature. Native GLP-1 and GLP-1R agonists elicit renal effects. Independently of renal plasma flow and glomerular filtration rate, GLP-1 has a natriuretic effect but only during volume expansion. This is associated with high renal extraction of GLP-1, suppression of angiotensin II, and increased medullary as well as cortical perfusion. These observations may potentially indicate that impaired GLP-1 sensing could establish a connection between salt sensitivity and insulin resistance. It is concluded that a functional GLP-1 kidney axis exists in humans, which may play a role in renoprotection.

Тубулоинтерстициальный нефрит с увеитом: серия клинических наблюдений

Tubulointerstitial nephritis and uveitis syndrome (TINU) is a rare autoimmune disease that develops predominantly in young people and is characterized by variable clinical manifestations and an uncertain prognosis. A single-center retrospective observational study included 3 pediatric patients (a girl and two boys) with clinically and morphologically confirmed TINU. Age of onset, clinical symptoms, gender-age-height-standardized blood pressure (BP), proteinuria (g/l), excretion level of β2-microglobulin, glucose, phosphorus in urine, blood pH and bicarbonate levels, Bedside Schwartz equation estimated glomerular filtration rate (eGFR, ml/min/1.73 m2, norm≥90 ml/min/1.73 m2), ophthalmoscopy data and the therapy were analyzed at the time of disease manifestation and during the follow-up. The duration of follow-up ranged from 3 to 7 years. The disease debuted at the age of 10 to 14 y/o with severe symptoms of intoxication, inflammatory activity, acute kidney damage (eGFR=22 to 35 ml/min/1.73 m2) and the development of Fanconi syndrome. Anterior uveitis had manifested in 1 to 5 months after the kidney disease. The TINU diagnosis was established after 6 to 9 months from the onset of the disease. All children received systemic steroid therapy coupled with the local treatment for uveitis. A significant decrease in blood creatinine levels and urine β2-microglobulin excretion with partial restoration of renal filtration function was noted by the sixth month of the therapy. All children developed chronic kidney disease (CKD) stages 2 to 3 over time. Stable remission of uveitis was achieved in 2 children after 3 to 10 months of treatment without complications; and in one patient a subacute uveitis led to the secondary changes in the cornea and decreased visual acuity. Conclusion: children with TINU have a high risk of developing CKD as a result of acute kidney disease; uveitis is characterized by a chronic course and, in the absence of remission, can lead to the development of ophthalmological complications.

Folic acid antioxidant supplementation to binge drinking adolescent rats improves hydric-saline balance and blood pressure, but fails to increase renal NO availability and glomerular filtration rate.

Binge drinking (BD) is an especially pro-oxidant pattern of alcohol consumption, particularly widespread in the adolescent population. In the kidneys, it affects the glomerular filtration rate (GFR), leading to high blood pressure. BD exposure also disrupts folic acid (FA) homeostasis and its antioxidant properties. The aim of this study is to test a FA supplementation as an effective therapy against the oxidative, nitrosative, and apoptotic damage as well as the renal function alteration occurred after BD in adolescence. Four groups of adolescent rats were used: control, BD (exposed to intraperitoneal alcohol), control FA-supplemented group and BD FA-supplemented group. Dietary FA content in control groups was 2 ppm, and 8 ppm in supplemented groups. BD provoked an oxidative imbalance in the kidneys by dysregulating antioxidant enzymes and increasing the enzyme NADPH oxidase 4 (NOX4), which led to an increase in caspase-9. BD also altered the renal nitrosative status affecting the expression of the three nitric oxide (NO) synthase (NOS) isoforms, leading to a decrease in NO levels. Functionally, BD produced a hydric-electrolytic imbalance, a low GFR and an increase in blood pressure. FA supplementation to BD adolescent rats improved the oxidative, nitrosative, and apoptotic balance, recovering the hydric-electrolytic equilibrium and blood pressure. However, neither NO levels nor GFR were recovered, showing in this study for the first time that NO availability in the kidneys plays a crucial role in GFR regulation that the antioxidant effects of FA cannot repair.

2529. Population pharmacokinetic models for cefepime and enmetazobactam derived from pooled Phase 1 to Phase 3 clinical studies

Abstract Background The investigational β-lactam/β-lactamase inhibitor combination of cefepime (FEP)/enmetazobactam (ENM) met criteria for non-inferiority and superiority compared to piperacillin/tazobactam in a phase 3 clinical trial of adult patients with complicated urinary tract infections (cUTI)/acute pyelonephritis (AP). In this study, a population pharmacokinetic (PK) model is presented that describes FEP and ENM plasma PK in adult cUTI/AP patients. Methods Plasma PK samples were analyzed from participants receiving FEP (n=588) and ENM (n=649) in three phase 1 (n=132), and single phase 2 (n=43) and phase 3 (n=488) clinical trials. Population PK parameters were assessed and the relationship between different covariates and model parameters were investigated. The effect of infection on disposition was assessed by testing disease covariates on fixed and random effects for all PK parameters. Results A two-compartment model with linear clearance of FEP (5.95 L/h) and ENM (7.68 L/h) from the central compartment best described the PK of both compounds. Common covariates for both compounds were de-indexed estimated glomerular filtration rate (eGFR), age, and body weight while ENM PK covariates also included cUTI infection and sex. Simulations showed that the only covariate requiring dose adjustment was renal function. The final model simultaneously described FEP and ENM plasma PK, which enabled estimates of the correlation of the random effects between PK parameters. Clearances and volumes of distribution (Vd) were strongly correlated within individuals between the two compounds (correlation coefficients >0.9). Variability was higher in cUTI patients although differences in mean ENM or FEP exposures between healthy subjects and cUTI patients were negligible. The total Vd was 16.9 L for FEP and 20.6 L for ENM. Clearance of both agents was found to depend on de-indexed eGFR (covariate coefficients ≥0.83), suggesting that renal filtration is the predominant clearance mechanism. The terminal elimination half-life was 2.2 h for FEP and 2.0 h for ENM. Final population PK model population parameter estimates for cefepime and enmetazobactam determined from the pooled phase 1 to phase 3 clinical studies Conclusion The population PK models for FEP and ENM predict exposures in cUTI patients, including subjects with renal impairment. These models support Monte-Carlo simulations and target attainment estimations in adult cUTI/AP patients. Disclosures Adam Belley, PhD, Allecra Therapeutics SAS: Advisor/Consultant Patrick Velicitat, MD, Allecra Therapeutics SAS: Salary

Warfarin and bisphosphontes interaction in patients undergoing total knee arthroplasty

BackgroundPatients undergoing knee arthroplasty (TKA) surgery need anticoagulant therapy, mainly warfarin for prevention of venous thromboembolism (VTE). Warfarin is mainly eliminated by renal glomerular filtration where 92 % of warfarin is excreted in urine. Warfarin overdose may lead to significant bleeding and warfarin underdosing may cause VTE and other complications. Thus, international normalized ratio (INR) monitoring is crucial in TKA patients taking warfarin. Great interest has been expressed in bisphosphonate to reduce periprosthetic osteoporosis in patients undergoing total joint arthroplasty. Many human case reports and cohort studies proved bisphosphonates induced impaired renal function. ObjectivesThe main goal of the current study is to examine the pharmacodynamin effect of bisphosphonates on warfarin excretion and clinical effects in patients undergoing TKA surgery. MethodsFifty patients undergoing TKA were recruited in the current study. Twenty five patients were given warfarin and twenty five patients were given warfarin and bisphosphonates starting three days after surgery. INR, major bleeding events and minor bleeding events were followed up in all recruited patients for one month after surgery. Resultswarfarin plus zoledronic acid group had significantly higher percent of post INR greater than 4 (p = 0.022) and significantly higher percent of minor bleeding events (p = 0.041) than warfarin only group. ConclusionConcomitant administration of bisphosphonates may increase warfarin bleeding adverse effects in elderly patient undergoing TKA.

Changes in common carotid artery elasticity in solid organ recipients

Background. Cardiovascular diseases are very common among solid organ recipients. They are associated with worsening transplant outcomes. Arterial vascular wall elasticity is an important prognostic indicator and a risk marker for cardiovascular events. Noninvasive measurement of common carotid artery (CCA) elasticity may be useful in assessing cardiovascular risk in solid organ recipients.Objective: To conduct a comparative analysis of indicators of CCA elasticity in solid organ recipients and to study their relationship with factors that potentially have a negative impact on the risk of adverse events.Materials and methods. The study included 154 patients aged 10 to 75 years, including heart (n = 77), liver (n = 9), and kidney (n = 35) recipients, as well as 33 patients with end-stage heart failure waitlisted for heart transplantation (HT). In all participants, carotid artery ultrasound was performed, pulse wave velocity was measured, and CCA elasticity was calculated.Results. CCA elasticity was found to be strongly inversely correlated with age, body mass index, systolic blood pressure, renal tubular filtration rate, CCA intima media thickness, and aortic pulse wave velocity. In heart recipients, CCA elasticity was significantly lower than in liver and kidney recipients (p = 0,002) and it inversely correlated with the length of time elapsed after transplantation, which is probably associated with cardiac denervation.Conclusion. CCA elasticity calculated via noninvasive ultrasound reflects the degree of adverse effects of pathological factors on the main arteries in solid organ recipients.

Transcriptomic changes in glomeruli in response to a high salt challenge in the Dahl SS rat.

Salt sensitivity impacts a significant portion of the population and is an important contributor to the development of chronic kidney disease. One of the significant early predictors of salt-induced damage is albuminuria, which reflects the deterioration of the renal filtration barrier: the glomerulus. Despite significant research efforts, there is still a gap in knowledge regarding the molecular mechanisms and signaling networks contributing to instigating and/or perpetuating salt-induced glomerular injury. To address this gap, we used 8-wk-old male Dahl salt-sensitive rats fed a normal-salt diet (0.4% NaCl) or challenged with a high-salt diet (4% NaCl) for 3 wk. At the end of the protocol, a pure fraction of renal glomeruli obtained by differential sieving was used for next-generation RNA sequencing and comprehensive semi-automatic transcriptomic data analyses, which revealed 149 differentially expressed genes (107 and 42 genes were downregulated and upregulated, respectively). Furthermore, a combination of predictive gene correlation networks and computational bioinformatic analyses revealed pathways impacted by a high salt dietary challenge, including renal metabolism, mitochondrial function, apoptotic signaling and fibrosis, cell cycle, inflammatory and immune responses, circadian clock, cytoskeletal organization, G protein-coupled receptor signaling, and calcium transport. In conclusion, we report here novel transcriptomic interactions and corresponding predicted pathways affecting glomeruli under salt-induced stress.NEW & NOTEWORTHY Our study demonstrated novel pathways affecting glomeruli under stress induced by dietary salt. Predictive gene correlation networks and bioinformatic semi-automatic analysis revealed changes in the pathways relevant to mitochondrial function, inflammatory, apoptotic/fibrotic processes, and cell calcium transport.

A bimolecular modification strategy for developing long-lasting bone anabolic aptamer

The molecular weight of nucleic acid aptamers (20 kDa) is lower than the cut-off threshold of the renal filtration (30-50 kDa), resulting in a very short half-life, which dramatically limits their druggability. To address this, we utilized HC and DA, two newly designed coupling agents, for synergistic binding to human serum albumin (HSA). Both HC and DA are conjugated to a bone anabolic aptamer (Apc001) against sclerostin to form an Apc001OC conjugate with high binding affinity to HSA. Notably, HC and DA could synergistically facilitate prolonging the half-life of the conjugated Apc001 and promoting its bone anabolic potential. Using the designed blocking peptides, the mechanism studies indicate that the synergistic effect of HC-DA on pharmacokinetics and bone anabolic potential of the conjugated Apc001 is achieved via their synergistic binding to HSA. Moreover, biweekly Apc001OC at 50mg/kg shows comparable bone anabolic potential to the marketed sclerostin antibody given weekly at 25mg/kg. This proposed bimolecular modification strategy could help addressing druggability challenge for aptamers with a short half-life.

IMPACT OF ACUTE EXPERIMENTAL BLOOD LOSS ON DIURESIS AND FILTERING CAPACITY OF KIDNEYS AND EFFICACY OF CORRECTION WITH RINGER’S LACTATE SOLUTION IN COMBINATION WITH 2-ETHYL-6-METHYL-3-HYDROXYPYRIDINE SUCCINATE

Introduction: The kidneys remain one of target organs in acute blood loss of various genesis. Reduced perfusion leads to an increase in renal insufficiency, primarily characterized by decreased urine production and glomerular filtration rate. Timely restoration of lost blood volume deficit stands as a critical objective in addressing hypovolemic shock. Among the first-line therapeutic approaches, the administration of balanced crystalloids in a 1:1 ratio relative to the lost blood volume has demonstrated efficacy; the combined use of antioxidants is regarded as promising. This study aims to investigate the impact of acute experimental blood loss on diuresis and kidney filtration capacity, assess the effectiveness of correction with Ringer's lactate solution in combination with 2-ethyl-6-methyl-3-hydroxypyridine succinate.
 Materials and Methods: In our experiments, we induced acute blood loss equivalent to 2% of the body mass in rats and evaluated kidney function using a water stress method after 1, 3, and 7 days. We measured diuresis, creatinine levels in blood serum and urine, and glomerular filtration rate. To address the effects of blood loss, we administered Ringer's lactate solution separately and in combination with 2-ethyl-6-methyl-3-hydroxypyridine succinate.
 Results: Following the induction of acute blood loss, there was a significant reduction in diuresis and glomerular filtration rate, accompanied by an increase in creatinine levels in both blood serum and urine. These impairments worsened over the course of 1 to 7 days. Comparing the efficacy of infusion therapy with Ringer's lactate solution alone and in combination with 2-ethyl-6-methyl-3-hydroxypyridine succinate after 7 days revealed a significantly more pronounced increase in diuresis, glomerular filtration rate, and a reduction in urine creatinine levels in the combined therapy group. These findings suggest the promising potential of combined therapy in preventing renal dysfunction in the context of acute blood loss.
 Conclusions: Acute blood loss equivalent to 2% of body mass leads to disturbances in diuresis and renal filtration capacity. The administration of Ringer's lactate solution in conjunction with 2-ethyl-6-methyl-3-hydroxypyridine succinate mitigates the effects of acute blood loss and yields a more substantial improvement compared to rats treated with Ringer's lactate solution alone.

Investigating kidney function changes in young adults with COVID-19: Serum creatinine level, glomerular filtration rate, and biochemical profile analysis

The study’s objective was to comprehensively assess kidney function alterations in patients with COVID-19. The study was carried out in Moscow (Russia) in 2021. 100 patients of 19-30 years old (51 females and 49 males) took part in the survey. The study collected participant data on basal urine, serum creatinine, and estimated glomerular filtration rate from medical histories before COVID-19 infection. COVID-19 diagnosis (delta strain) was confirmed by polymerase chain reaction test. Serum creatinine was measured, considering age and race. Micro-albuminuria levels from daily urine samples were established. Laboratory blood tests included quantitative indices of blood-forming elements, hemoglobin levels, and biochemical parameters. Based on the results, the study observed a slight increase in serum creatinine levels after COVID-19 infection, with concentrations of 78.4±6.4 mmol/L before infection and 87.5±7.7 mmol/L after the disease (p≥0.05). The microalbuminuria-creatinine ratio also showed an increase. The glomerular filtration rate in renal glomeruli declined from 93.3±10.1 mL/min/1.73 m<sup>2</sup> before infection to 78.9±8.7 mL/min/1.73 m<sup>2</sup> after the disease (p≥0.05). These findings suggest a trend towards decreased kidney function in young patients with moderate COVID-19 severity. However, normoalbuminuric compared to creatinine was significantly higher than normal after COVID-19. Urine tests indicated a trend of decreased renal glomerular filtration rate. Clinical symptoms included high temperature, weakness, cough, and, in some cases, liquid stools. Laboratory findings revealed significant deviations in hematocrit, neutrophil, and eosinophil concentrations. Parallel tests focusing on cystatin C and beta-2 macroglobulin are recommended to assess kidney function and identify potential dysfunction.

Angiotensin II in liver transplantation (AngLT-1): protocol of a randomised, double-blind, placebo-controlled trial

IntroductionCatecholamine vasopressors such as norepinephrine are the standard drugs used to maintain mean arterial pressure during liver transplantation. At high doses, catecholamines may impair organ perfusion. Angiotensin II is a...

Deletion of Neph1: Important for Renal Filtration but Critically Decisive for Patterning of the Enteric Nervous System

Deletion of Neph1: Important for Renal Filtration but Critically Decisive for Patterning of the Enteric Nervous System

Exploring an Unknown Corner of a Well-Known Topic: HIIE Influence on Renal Health and Filtration in Healthy Individuals Free of Cardiometabolic Diseases.

Aerobic exercise, specifically high-intensity interval exercise (HIIE), and its effects on renal health and filtration (RHF) are not well understood. Several studies support incorporating contemporary biomarkers serum cystatin C (CyC) and urine epidermal growth factor (uEGF) to combat the volatility of serum creatinine (sCr). Using these biomarkers, we examined the acute influences HIIE has on RHF to determine if there is a ceiling effect in healthy populations. The purpose was to determine the influence of an acute bout of HIIE on RHF. Thirty-six participants (n = 22 males; n = 14 females; age 37.6 ± 12.4 years.; BF% 19.2 ± 7.1%; VO2max 41.8 + 7.4 mL/kg/min) completed 30 min of HIIE on a treadmill (80% and 40% of VO2reserve in 3:2 min ratio). Blood and urine samples were obtained under standardized conditions before, 1 h, and 24 h post-exercise. CyC, sCR, uEGF, urine creatinine (uCr), uCr/uEGF ratio, and multiple estimates of glomerular filtration rate (eGFR) Modification of Diet in Renal Disease (MDRD) and CKD-EPI equations were used. The analysis employed paired sample t-tests and repeated measures ANOVAs. CyC, uEGF, uCr, and uCr/uEGF ratio concentrations were not altered between timepoints. sCr increased 1 h post-exercise (p > 0.002) but not at 24 h post-exercise. eGFR decreased in the MDRD and CKD-EPI equations at 1 h (p > 0.012) with no changes at 24 h post-exercise. CyC and sCr/CyC demonstrated no significant changes. CyC and uEGF are not altered by acute HIIE. The results demonstrate a potential ceiling effect in contemporary and traditional biomarkers of RHF, indicating improvements in RHF may be isolated to populations with reduced kidney function.

Effects of Microplastic (MP) Exposure at Environmentally Relevant Doses on the Structure, Function, and Transcriptome of the Kidney in Mice.

As a common emerging environmental pollutant, microplastics (MPs) have been detected in a variety of environmental media and human bodies. The potential toxic effects and mechanisms of MPs need to be revealed urgently. MPs can be deposited in the kidney, and exposure to high doses of MPs can cause nephrotoxicity in experimental animals. In this study, we investigated the effects of exposure to polystyrene microplastics (PS-MPs) at environmentally relevant doses (0.1 and 1 mg/L) on kidney structure, function, and transcriptome in mice. We found that mice exposed to PS-MPs in drinking water for eight weeks had no change in body weight or kidney coefficient. PS-MPs administration decreased the levels of blood urea nitrogen (BUN) in mice, while serum creatinine (CRE) and uric acid (UA) concentrations were unaffected. Through using periodic acid-Schiff (PAS) and Masson staining, we discovered that the glomerular tuft area increased in the PS-MP-treated mice, while the degree of renal fibrosis remained unchanged. Furthermore, renal cortex transcriptomic analysis identified 388 and 303 differentially expressed genes (DEGs) in the 0.1 and 1 mg/L dose groups, respectively. The DEGs were highly enriched in mitochondrial-related terms and pathways of thermogenesis and oxidative phosphorylation. Moreover, protein-protein interaction (PPI) network analysis revealed that cytochrome b-c1 complex subunit 10 (UQCR11) and cytochrome c oxidase subunit 3 (MT-CO3) were important node proteins. These findings suggest that environmental exposure to MPs can cause abnormalities in renal structure and filtration function and that long-term exposure to MPs may be a risk factor for renal disease.

Maternal dexamethasone exposure does not affect glucose tolerance but alters renal haemodynamics in F1 rats in a sex-dependent manner.

Prenatal programming with dexamethasone increases the risk of the development of hyperglycaemia and insulin resistance, leading to diabetes in adulthood. Dexamethasone also causes a decline in renal glomerular filtration in the adult offspring. Sodium-glucose cotransporter-2 (SGLT2) plays a significant role in regulating blood glucose and renal haemodynamics in diabetic patients. However, the role of SGLT2 in dexamethasone-induced programming and the putative sex-dependent effects on the changes named earlier is unknown. Therefore, this study aimed to investigate the impact of maternal dexamethasone treatment on glucose tolerance, insulin sensitivity, renal perfusion and renal function in adult male and female offspring and the possible contribution of SGLT2 to these changes. Pregnant Sprague Dawley rats (F0 ) were treated with either vehicle or dexamethasone (0.2 mg/kg ip) from gestation Day 15 to 20. F1 males and F1 females were randomly selected from each mother at 4 months of age. There was no change in serum Na+ , Na+ excretion rate, glucose tolerance or insulin sensitivity in F1 male or female rats. However, dexamethasone caused significant glomerular hypertrophy and decreases in CSinistrin and CPAH indicating decreased glomerular filtration rate and renal plasma flow, respectively, in dexamethasone-treated F1 male but not female rats. Dexamethasone did not affect SGLT2 mRNA or protein expression in F1 males or females. We conclude that dexamethasone-mediated prenatal programming of glomerular volume, renal function and haemodynamics is sex-dependent, occurring only in adult male offspring.

Unraveling the Effects of Acute Inflammation on Pharmacokinetics: A Model-Based Analysis Focusing on Renal Glomerular Filtration Rate and Cytochrome P450 3A4-Mediated Metabolism.

A physiologically based model incorporating renal and hepatic drug clearance was implemented. Functions correlating IL-6 levels with GFR and in vitro CYP3A4 activity were derived and incorporated into the modeling framework. We then simulated treatment scenarios for hypothetical drugs by varying the IL-6 levels, the contribution of renal and hepatic drug clearance, and protein binding. The relative change in observed area under the concentration-timecurve (AUC) was computed for these scenarios. Inflammation showed opposite effects on drug exposure for drugs eliminated via the liver and kidney, with the effect of inflammation being inversely proportional to the extraction ratio (ER). For renally cleared drugs, the relative decrease in AUC was close to 30% during severe inflammation. For CYP3A4 substrates, the relative increase in AUC could exceed 50% for low-ER drugs. Finally, the impact of inflammation-induced changes in drug clearance is smaller for drugs with a larger unbound fraction. This analysis demonstrates differences in the impact of inflammation on drug clearance for different drug types. The effects of inflammation status on pharmacokinetics may explain the inter-individual variability in pharmacokinetics in critically ill patients. The proposed model-based analysis may be used to further evaluate the effect of inflammation, i.e., by incorporating the effect of inflammation on other drug-metabolizing enzymes or physiological processes.

RGS1 mediates renal interstitial fibrosis through activation of the inflammatory response

Renal interstitial fibrosis (RIF) is considered as a common pathway for all patients with chronic kidney disease (CKD) to progress to end-stage kidney disease (ESRD). The basic pathological manifestation is the increase of matrix component in the tubular interstitium, while the injury of tubular epithelial cells in the renal interstitium and the excessive accumulation of matrix will eventually lead to tubular atrophy and obstruction, loss of effective renal units, and finally impaired renal filtration function. The relevant mechanism of RIF remains unclear. The present study will investigate the function and relevant mechanism of RGS1 in RIF. The RIF-related microarrays GSE22459 and GSE76882 were downloaded and analyzed. Renal parenchymal atrophic calyx tissues were collected from clinical RIF patients. Cellular inflammation, fibrosis and animal RIF models were constructed using Lipopolysaccharide (LPS), TGF-β1 and unilateral ureteral occlusion (UUO). HE and Masson staining were performed to detect morphological alterations of renal tissue samples. qRT-PCR, Western blot and ELISA were carried out to detect the expression of relevant genes/proteins. RGS1 is a gene co-differentially expressed by GSE22459 and GSE76882. RGS1 expression was elevated in renal tissues of RIF patients, cells and animal RIF models. Knockdown of RGS1 inhibited renal cell inflammatory response, fibrosis and renal fibrosis in RIF mice. Overexpression of RGS1 plays the opposite role. Knockdown of RGS1 inhibited the inflammatory response in the RIF cell and mouse model. Targeting RGS1 might be a potential therapeutic strategy for RIF treatment.

Abstract P397: Preservation Of Renal Microvascular Function In Ischemia-reperfusion Induced Kidney Injury In Rats

Proper renal blood flow and glomerular filtration rate are critical for maintaining normal kidney function by precisely adjusting preglomerular microvascular resistance. Renal ischemia-reperfusion (IR) insult markedly increased mRNA expression of the inflammatory chemokine (C-C motif) Ligand 2 (CCL2) in rat kidney tissues. We hypothesized that depletion of macrophages prevented IR-induced renal autoregulatory impairment via reduction of CCL2 in preglomerular microvessels (PGMV). IR was induced in male rats by 60-minute bilateral renal artery occlusion followed by reperfusion. Some IR rats were treated with the selective macrophage inhibitor, Liposome-encapsulated clodronate (LC) following reperfusion and repeated 72 hours post-IR. Afferent arteriolar autoregulatory reactivity was assessed using the in vitro blood-perfused juxtamedullary nephron preparation in sham, IR, and IR+LC rats on day 7. Afferent arterioles from sham-operated rats exhibited pressure-dependent vasoresponsiveness. The baseline arteriolar diameter averaged 13.4 ± 0.5 μm at renal perfusion pressure (RPP) of 100 mmHg. Diameter increased to 117 ± 4% of baseline at RPP of 65 mmHg and decreased to 69 ± 2% at 170 mmHg, respectively. In contrast, afferent arterioles from IR rats only increased to 104 ± 2% and decreased to 91 ± 5% of baseline at 65 and 170 mmHg, respectively (P < 0.05 vs sham), indicating the impaired autoregulatory capacity in IR rats. LC-treated IR rats, however, markedly improved the pressure-dependent vasoresponsiveness. A decrease in RPP to 65 mmHg resulted in a 124 ± 17% increase in the baseline diameter, whereas increasing RPP to 170 mmHg led to a 74 ± 7% decrease in diameter. Additionally, IR markedly increased CCL2 mRNA expression in isolated PGMV by 10-fold 7 days post-IR. IR also elevated NADPH oxidase subunits (gp91 phox , P67 phox , and P47 phox ). Significantly, LC treatment suppressed mRNA expression of CCL2, gp91 phox , P67 phox , and P47 phox in IR-PGMV. In conclusion, depletion of macrophages preserves afferent arteriolar autoregulatory capacity and reduces PGMV CCL2 mRNA expression in IR rats, suggesting a critical role of macrophages in mediating renal microvascular autoregulatory impairment in IR-induced kidney injury via the increase of CCL2 in PGMV.

Drug–drug interaction signals between loop diuretics and teicoplanin during acute kidney injury evaluated using Japanese spontaneous adverse drug event reports

Teicoplanin can cause acute kidney injury, but little is known about the risk of acute kidney injury when teicoplanin is co-administered with loop diuretics (a powerful diuresis), which can alter renal hemodynamics and glomerular filtration rate. We performed a signal detection analysis using a Japanese adverse event database to determine the additive impact of loop diuretics on acute kidney injury associated with teicoplanin. The dataset originated between April 2004 and August 2022. Disproportionality analysis was performed to detect the signals for acute kidney injury (the Standardized MedDRA Query) when co-administered teicoplanin or vancomycin (a positive control) with individual diuretics, including loop diuretics. Multivariate logistic regression analysis was tested to estimate the adjusted reporting odds ratio (aROR) and 95% confidence interval (95% CI). There were 147 and 515 events of acute kidney injury associated with teicoplanin and vancomycin, respectively. A significant positive signal for acute kidney injury when teicoplanin was co-administered with loop diuretics was present (aROR 4.83, 95% CI 3.52–6.61, p < 0.0001). Contrastingly, no significant signals were observed when vancomycin was co-administered with any diuretics. These findings suggest that co-administered loop diuretics may have an unfavorable effect on acute kidney injury while undertaking teicoplanin but not vancomycin.