Progression To End-stage Kidney Disease Research Articles

Gut Microbiome and Microbiome-Derived Metabolites in Patients with End-Stage Kidney Disease.

The composition of the gut microbiome is altered in patients with chronic kidney disease (CKD). Dysbiosis leads to decreased levels of stool organic acids (OAs) and systemic inflammation, followed by accumulation of uremic toxins (UTs) and the development of end-stage kidney disease (ESKD). We assessed the relationship between the microbiome and UT levels or the development of ESKD by comparing patients undergoing hemodialysis (HD) and those with normal renal function (NRF). This cross-sectional study recruited 41 patients undergoing HD and 38 sex- and age-matched patients with NRF, and gut microbiome, levels of plasma UTs, inflammatory markers, and stool OAs were compared. The indices of beta-diversity differed significantly between patients with NRF and those undergoing HD, and between patients undergoing HD with and without type 2 diabetes. The levels of stool total OA, inflammatory markers, and UTs differed significantly between the patients with NRF and those undergoing HD. The combined main effects of type 2 diabetes and kidney function status were accumulation of indoxyl sulfate and p-cresyl sulfate. The relative abundances of Negativicutes and Megamonas were associated with development of ESKD and with the levels of UTs, even after adjustment for factors associated with the progression of ESKD. The present study indicates that the gut environment differs between patients with NRF and those undergoing HD and between patients undergoing HD with and without type 2 diabetes. Moreover, ESKD patients with diabetes accumulate more UTs derived from the gut microbiome, which might be associated with cardio-renal diseases and poor prognosis.

417-P: Functional Characterization of a Rare, Pathogenic Missense Variant Implicates FRAS1 as a Novel Gene for Risk of Progression to End-Stage Kidney Disease in Diabetes

Progressive renal decline is the central manifestation of diabetic nephropathy (DN) that ultimately leads to end-stage kidney disease (ESKD). Leveraging an innovative family-based approach that integrates electronic medical record data, a unique population-based genealogy resource, and next-generation sequencing, we recently identified a rare missense variant (p.R2516C, allele frequency=0.00002) in FRAS1, which encodes an extracellular matrix protein that regulates epidermal basement membrane adhesion and mediates glomerular integrity, in a family with diabetes and ESKD. While this rare missense variant is predicted to be deleterious (CADD score=32), whether this impacts FRAS1 function is unknown; here, we set out to assess the functional impact of this variant. To do so, we used CRISPR-Cas9 gene editing technology to generate 3 novel HEK293 cell lines (2 FRAS1 knock-in cell lines (a synonymous p.H2520H control cell line and a missense p.R2516C variant cell line) and a FRAS1 knock-out cell line) and performed in vitro cell migration and cell adhesion assays. Relative to the control cell line, both the FRAS1 knock-out cell line and the missense variant cell line displayed significantly inhibited cell migration (p = 1.54X10-13 and p = 5.05X10-5, respectively). Similarly, cell adhesion was significantly inhibited in cells in which FRAS1 was knocked out and in those carrying the p.R2516C variant compared to the control cell line (p = 6.72X10-9 and p = 6.63X10-6, respectively). Together, these data suggest that the FRAS1 p.R2516C variant negatively impacts FRAS1 function and further implicates this gene as having a potential role in the progression of ESKD in individuals with diabetes. Disclosure T.Chen: None. M.B.Neeley: None. J.M.Lazaro-guevara: None. M.Pezzolesi: None. C.A.Simeone: None. A.Rodan: None. W.L.Holland: Research Support; SymbioCellTech, LLC. M.G.Pezzolesi: Research Support; Renalytix. Funding National Institutes of Health (R01DK128641)

#5214 RENAL TOLERABILITY OF SGLT-2 INHIBITORS COMBINING WITH RENIN-ANGIOTENSIN SYSTEM BLOCKERS AND MINERALOCORTICOID RECEPTOR ANTAGONISTS IN CKD

Abstract Background and aims Recently the sodium glucose cotransporter-2 (SGLT-2) inhibitors combining with angiotensin-converting enzyme (ACE) inhibitor or angiotensin-receptor II blocker (ARBs) or angiotensin-receptor neprilysin inhibitor (ARNI)) and mineralocorticoid receptor antagonist (MRA) ((triple therapy (TT)), would help prevent further progression of renal and cardiovascular (CV) endpoints including progression of end-stage kidney disease (ESKD). The degree to which data on TT initiation and discontinuation in cronic kidney disease (CKD) patients can be generalized to patients in real-world practice is unclear. Aims to evaluate renal tolerability to the TT at target doses as well as clinical incidents and dosage adjustments. To analyze the risk factors for TT discontinuation. Method A retrospective cohort study was carried out in patients ≥18 years old with chronic kidney disease (CKD) treated with TT in Rey Juan Carlos Hospital between January 2019 to December 2022. The collected clinical data included age, gender, associated morbidities, serum creatinine (Scr), estimated glomerular filtration rate (eGFR), potassium, sodium levels, dose adjustments before administration of TT and in the first year of follow up. Multivariate logistic models were performed to evaluate the risk factors to dosage adjusted and discontinuation of TT. Results Among 104 patients treated with TT were included. Medium age was 69 years old (range, 37-91). Most of them were men, 78% (81). The main cause to initiate TT was cardiorenal syndrome 59% (61). Before to initiate TT, in 35% patients the treatment was adjusted. The main modification was reduced or discontinuation of diuretics (loop or thiazide) therapy 23% (24/104). In the first year of follow up, in 69 patients (66%) it was necessary dosage adjustments, being the reduced of MRA (spironolactone and eplerenone) the main modification treatment 38% (26/69). The major cause of dose adjustment was developed of acute kidney injury (AKI) in 43 patients (41%). According to KDIGO criteria, 38 patients (88%) reached stage 1; 4 patients (9%) stage 2 and 1 case (2%) stage 3. The independent risk factor associated with dosage adjustment were AKI development (OR: 28.57; 95% CI 6.04-134.4; P = 0.0001) adjusted by sex and age. Despite the dosage adjustment and titers, in 29 patients (28%) TT was discontinued in a median time of 4 months (IQR 2–11) after its initiation. The risk factor associated with TT discontinuation were AKI developed (P = 0,003) and eGFR at the 12 months of follow up (P = 0,01). There were no significant excess risks of symptomatic hypotension, volume depletion, and hyperkalemia after a year of follow up. Conclusions The renal tolerability of use to triple therapy in chronic kidney disease appears to be low. The AKI development was the main risk factor of dosage adjustment and discontinuation of TT. Its necessary to clarify which is the best way to maximizing renal tolerability in this complex groups of patients. The use of early combination therapy requires careful assessment. Its important to find strategies to guide clinicians about the steps and challenges to improving overall use of triple therapy tolerability and dosage adjustment.

Protective Role of Angiotensin II type 2 receptor (AT2R) in High Salt Diet‐Induced Low Molecular Weight Proteinuria and Loss of Megalin in the Kidney

Proteinuria is a cause and a risk factor for tubulointerstitial injury with the progression of end‐stage kidney disease. Proteinuria is a function of the glomerular filtration of protein and the reabsorption of protein from the post‐glomerular filtrate by the endocytic receptors, megalin and cubilin, localized in the renal proximal tubules. We have shown that treatment with the angiotensin‐II type 2 receptor (AT2R) agonist compound 21 (C21) for 2 weeks reduces proteinuria in obese Zucker rats (OZR) fed with high salt diet (HSD). OZR is a salt‐sensitive model but has no effect on blood pressure in the first 3 days of HSD treatment. However, the early cellular and molecular mechanism of proteinuria in response to HSD and the protective effect of AT2R activation is unknown. Therefore, the present study is designed to determine the molecular/cellular mechanism of AT2R‐mediated protection against HSD‐induced proteinuria, independent of glomerular injury in obesity. We hypothesize that AT2R activation prevents the loss of megalin in proximal tubule epithelial cells and thereby decreases the urinary excretion of low molecular weight (LMW) proteins in HSD fed obese rats. Male OZR (11–14 weeks of age) were fed on normal salt diet (NSD) (0.4%) or HSD (4%) for 2 days with and without treatment with C21. The animals were placed in metabolic cages for collecting urine at various time intervals namely 6, 12, 24 and 48 hours. We observed that HSD caused proteinuria at 24 hrs. and was prevented by C21 treatment. Further analysis by gel electrophoresis revealed that proteinuria was based on LMW protein (<60 kDa) excretion in the urine. This observation was confirmed by no change in albuminuria by HSD and C21. Dot blot analysis and confocal immunofluorescence microscopy revealed that megalin and not cubilin, was significantly decreased in HSD treatment group and the remaining megalin was mostly present in the cytosolic compartment with negligible expression on plasma membrane, suggesting megalin recycling impairment. The C21 treatment restored megalin back to the plasma membrane. FcRn is an exclusive receptor for albumin transport, which remained unaltered by HSD and C21. Western blot of nephrin and podocin, indices of glomerular filtration apparatus, remained unchanged suggesting structural integrity of the glomerular filtration assembly. Consistent to this notion, GFR measured by creatinine clearance method remained same in all the three groups. HSD caused a significant increase in the urinary sodium excretion, which was not affected by C21 treatment and the plasma sodium concentration in all the groups remained the same. Overall, the data suggest that acute feeding of HSD causes LMW proteinuria due to reduction as well as cytosolic expression of megalin in proximal tubule and not due to the change in the glomerular filtration. AT2R activation restores megalin expression and prevents proteinuria with a potential of long‐term protection against tubule‐interstitial injury and kidney disease.

Impact of acute kidney injury on long-term adverse outcomes in obstructive uropathy

Obstructive uropathy is known to be associated with acute kidney injury (AKI). This study aimed to investigate the etiologies, clinical characteristics, consequences and also assess the impact of AKI on long-term outcomes. This multicenter, retrospective study of 1683 patients with obstructive uropathy who underwent percutaneous nephrostomy (PCN) analyzed clinical characteristics, outcomes including progression to end-stage kidney disease (ESKD), overall mortality, and the impact of AKI on long-term outcomes. Obstructive uropathy in adults was most commonly caused by malignancy, urolithiasis, and other causes. AKI was present in 78% of the patients and was independently associated with preexisting chronic kidney disease (CKD). Short-term recovery was achieved in 56.78% after the relief of obstruction. ESKD progression rate was 4.4% in urolithiasis and 6.8% in other causes and older age, preexisting CKD, and stage 3 AKI were independent factors of progression. The mortality rate (34%) was highly attributed to malignant obstruction (52%) stage 3 AKI was also an independent predictor of mortality in non-malignant obstruction. AKI is a frequent complication of adult obstructive uropathy. AKI negatively affects long-term kidney outcomes and survival in non-malignant obstructions. A better understanding of the epidemiology and prognostic factors is needed for adult obstructive uropathy.

Klotho deficiency intensifies hypoxia-induced expression of IFN-α/β through upregulation of RIG-I in kidneys.

Hypoxia is a common pathway to the progression of end-stage kidney disease. Retinoic acid-inducible gene I (RIG-I) encodes an RNA helicase that recognizes viruses including SARS-CoV2, which is responsible for the production of interferon (IFN)-α/β to prevent the spread of viral infection. Recently, RIG-I activation was found under hypoxic conditions, and klotho deficiency was shown to intensify the activation of RIG-I in mouse brains. However, the roles of these functions in renal inflammation remain elusive. Here, for in vitro study, the expression of RIG-I and IFN-α/β was examined in normal rat kidney (NRK)-52E cells incubated under hypoxic conditions (1% O2). Next, siRNA targeting RIG-I or scramble siRNA was transfected into NRK52E cells to examine the expression of RIG-I and IFN-α/β under hypoxic conditions. We also investigated the expression levels of RIG-I and IFN-α/β in 33 human kidney biopsy samples diagnosed with IgA nephropathy. For in vivo study, we induced renal hypoxia by clamping the renal artery for 10 min in wild-type mice (WT mice) and Klotho-knockout mice (Kl-/- mice). Incubation under hypoxic conditions increased the expression of RIG-I and IFN-α/β in NRK52E cells. Their upregulation was inhibited in NRK52E cells transfected with siRNA targeting RIG-I. In patients with IgA nephropathy, immunohistochemical staining of renal biopsy samples revealed that the expression of RIG-I was correlated with that of IFN-α/β (r = 0.57, P<0.001, and r = 0.81, P<0.001, respectively). The expression levels of RIG-I and IFN-α/β were upregulated in kidneys of hypoxic WT mice and further upregulation was observed in hypoxic Kl-/- mice. These findings suggest that hypoxia induces the expression of IFN-α/β through the upregulation of RIG-I, and that klotho deficiency intensifies this hypoxia-induced expression in kidneys.

Relationship Between Sleep Quality and Quality of Life in Hemodialysis Patients: A Literature Review

Poor sleep quality can worsen hypertension, type 2 diabetes and obesity, thereby increasing the incidence of cardiovascular disease, as well as accelerating the progression of end-stage kidney disease and reducing survival rates. In hemodialysis patients, many factors affect the patient’s quality of life start from a psychological, physiological, social, and economic perspective can decreased the patient’s quality of life. To know about the relationship between sleep quality and quality of life in hemodialysis patients, this study uses a literature review method, based on the results of an article published within the last 10 years. From 5 journals that met the criteria, it was found that there was relationship between sleep quality and quality of life. There is a significant relationship between sleep quality and quality of life in hemodialysis patients.&#x0D; &#x0D; Keywords: Hemodialysis, Sleep quality, Quality of life.

Association of Infection With Human Papillomavirus and Development of End-Stage Kidney Disease in Taiwan

The association between human papillomavirus (HPV) infection status and the natural process of kidney diseases has been neglected as an area of research. Further studies are needed to clarify factors that may alter the progression of end-stage kidney disease (ESKD). To describe the rates of ESKD among patients with and without HPV infection. In this nationwide, population-based retrospective cohort study, data were collected from the National Health Insurance Research Database of Taiwan. A total of 76 088 individuals with HPV infection were enrolled from January 1, 2000, to December 31, 2012, and compared with a control group of 76 088 individuals who had never been diagnosed with HPV infection (at a 1:1 ratio propensity-score matched by age, sex, index year, and comorbidities) in the context of the risk of developing ESKD. Statistical analysis was performed between November 2019 and July 2020. HPV infection was defined according to the International Classification of Diseases, Ninth Revision, Clinical Modification codes. The main outcome was ESKD, as recorded in the Catastrophic Illness Patients database. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs, with the control group as a reference. Of 152 176 individuals (79 652 [52.3%] women; mean [SD] age, 34.4 [19.1] years), 76 088 individuals (50.0%) had HPV and 463 individuals (0.3%) developed ESKD. Incidence of ESKD was lower in individuals with HPV history than in those without HPV history (3.64 per 10 000 person-years vs 4.80 per 10 000 person-years). In the fully adjusted multivariate Cox proportional hazards regression model, individuals with a history of HPV infection had a significant decrease in risk of ESKD (adjusted HR, 0.72; 95% CI, 0.60-0.87) after adjusting for demographic characteristics, comorbidities, and comedications. In the subgroup analysis, individuals ages 50 to 64 years with HPV infection had a statistically significantly lower risk of ESKD compared with individuals ages 50 to 64 years with no HPV infection (adjusted HR, 0.48; 95% CI, 0.34-0.68; P < .001), while there was no significant reduction in risk for the other age groups (ie, 0-19, 20-49, and 65-100 years). In this study, a history of HPV infection was associated with a lower risk of subsequent ESKD. The mechanism behind this protective association remains uncertain. Future studies are required to clarify the possible biological mechanisms.

P0357VALIDATION OF THE ANCA RENAL RISK SCORE IN A LONDON COHORT: POTENTIAL IMPACT OF TREATMENT ON PREDICTION OUTCOME

Abstract Background and Aims A renal risk score was recently developed to predict the risk of progression to end stage kidney disease (ESKD) in patients with ANCA-associated glomerulonephritis (ANCA-GN). The score defines three risk groups, each with distinct renal survival at 36 months: 68% of high-risk patients reaching ESKD, compared to 26% and 0% in the medium- and low-risk groups, respectively. The majority of patients (101/115) used to define the risk score were treated with IV cyclophosphamide and steroids. At our centre, we employ a combined low-dose IV cyclophosphamide, rituximab and oral corticosteroid induction regimen, with or without plasma exchange (PEX) depending on disease severity, for ANCA-GN. A recent cohort study suggested this combination regimen may lead to better renal survival. We thus hypothesized that choice of remission-induction treatment may affect prediction accuracy of the risk tool. We retrospectively test the validity of the ANCA renal risk score in patients with ANCA-GN treated at our centre. Method All patients with newly diagnosed, biopsy-proven ANCA-GN from 2006-19 were identified from local renal histopathology database. Patients with relapsing ANCA-GN, EGPA, other coexisting GN, or missing data on induction therapy or eventual renal outcome were excluded. ANCA-negative pauci-immune GN was included. Baseline demographics, ANCA serology, initial therapy and parameters in the ANCA risk score (including % normal glomeruli, % tubular atrophy and interstitial fibrosis (TAIF), and estimated glomerular filtration rate were collected. All patients were stratified using the risk tool and Kaplan Meier survival analysis was applied to examine the ESKD prediction. Subgroup analysis was then performed for patients who received the combination regimen of cyclophosphamide and rituximab. Results 178 patients with a median follow up of 44 month were included in the analysis. The median age was 62 years and 82 patients (46%) were female. 94(53%) were MPO-ANCA positive, 66(37%) PR3-ANCA positive, 15 (8%) ANCA-negative, and 3 (2%) were double PR3/MPO-ANCA positive. 148 (83%) patients received the combination regimen, and 45 had concurrent PEX. Total of 37 (21%) patients reached ESKD. 29 (78%) of these, developed ESKD within 36 months of initial diagnosis. Using the risk score, 64(36%), 76(43%) and 38(21%) patients were deemed low-, medium- and high-risk, respectively. Very distinct poor renal survival at 36 months was seen in high-risk group (55% reaching ESKD, p&amp;lt;0.01), but was less apparent between low- (95%) and medium-risk (90%)(p=0.052) (Figure1); In the subgroup of patients treated with combination regimen without concurrent PEX, the high-risk subgroup continues to demonstrate poor renal survival at 36 months (60% ESKD), but renal survival between low- and medium-risk group were comparable (0 and 2% respectively, p=0.57) (Figure 2). Conclusion In our cohort, the ANCA Renal Risk Score reliably predicted rapid ESKD progression at 36-month in high-risk patients, but was less accurate for distinguishing patients with low-and medium-risk. The subgroup analysis suggested combined cyclophosphamide and rituximab therapy may have modified long-term renal outcome especially in the medium-risk cohort, influencing the accuracy of the prediction tool. Large multi-centre cohorts are required to further evaluate the potential impact of treatment on predicting outcome.

302-OR: ADA Presidents’ Select Abstract: The Balance of Vascular Tone in the Afferent (RA) and Efferent (RE) Arterioles Associates with Diabetic Kidney Lesions and Predicts Progression to End Stage Kidney Disease (ESKD) in Type 2 Diabetes (T2D)

The balance of RA and RE, a major determinant of intraglomerular pressure (P&amp;lt;glo), may be important in the initiation and progression of diabetic kidney disease (DKD). Although RA and RE are not directly measurable in humans these parameters can be estimated by the Gomez equation using measures of whole-kidney GFR and renal plasma flow (RPF), mean arterial pressure (MAP), hematocrit, and plasma oncotic pressure. We examined the association of the RA/RE ratio with ESKD incidence in 212 Pima Indians with T2D who underwent measures of GFR (iothalamate) and RPF (p-aminohippurate). RA/RE ratio’s association with kidney structural lesions was also examined in a subset of 111 participants. Of the 212 subjects (29% men; mean age 52 years, diabetes duration 22 years, MAP 92 mmHg, HbA1c 10.1%, GFR 111 ml/min; median ACR 99 mg/g), 57 progressed to ESKD during median follow-up of 18.4 years. Cox regression, adjusting for sex, baseline age, diabetes duration, HbA1c, renin-angiotensin system blocker use and GFR, indicated that each 1 SD increment in the RA/RE ratio conferred higher risk of ESKD (4.19; 95%CI 2.18-8.04). In addition, the correlation between the RA/RE ratio and mesangial fractional volume, a key predictor of DKD progression (R2=15%, P&amp;lt;0.0001), was stronger than the correlation between GFR and mesangial fractional volume (R2=7%, P=0.004). Elevated RA/RE ratio, reflective of low P&amp;lt;glo, strongly associates with incident ESKD, independent of GFR, and with the glomerular structural lesion that best predicts this ESKD progression. These data, directly challenging the hypothesis that intraglomerular hypertension drives DKD, are derived from whole-kidney GFR and RPF, and therefore do not necessarily reflect single-nephron function. Nevertheless, identifying the mechanisms underlying this hemodynamic imbalance and its potential ischemic influences may provide new therapeutic targets. Disclosure P. Saulnier: None. H.C. Looker: None. M. Mauer: None. R.G. Nelson: None. P. Bjornstad: Advisory Panel; Self; XORTX Therapeutics Inc. Consultant; Self; Bayer AG, Boehringer Ingelheim International GmbH, Bristol-Myers Squibb, Novo Nordisk Foundation. Research Support; Self; Horizon Pharma. Funding American Diabetes Association (1-08-CR-42 to R.G.N.); National Institute of Diabetes and Digestive and Kidney Diseases

Dab1 Contributes to Angiotensin II-Induced Apoptosis via p38 Signaling Pathway in Podocytes.

Numerous studies have found that angiotensin II (Ang II) participates in podocyte apoptosis and exacerbates progression of end-stage kidney disease (ESKD). However, its underlying mechanism remains largely unexplored. As a homolog of Drosophila disabled (Dab) protein, Dab1 plays a vital role in cytoskeleton, neuronal migration, and proliferation. In the present study, our data revealed that Ang II-infused rats developed hypertension, proteinuria, and podocyte injury accompanied by Dab1 phosphorylation and increased reelin expression in kidney. Moreover, Ang II induced podocyte apoptosis in vitro. Dab1 phosphorylation and reelin expression in podocytes were increased after exposure to Ang II. Conversely, Dab1 small interfering RNA (siRNA) exerted protective effects on Ang II-induced podocyte apoptosis, resulting in decreased p38 phosphorylation and reelin expression. These results indicated that Dab1 mediated Ang II-induced podocyte apoptosis via p38 signaling pathway.

MicroRNA-498 Inhibition Enhances the Differentiation of Human Adipose-Derived Mesenchymal Stem Cells into Podocyte-Like Cells.

Podocyte depletion is a key event in the progression of end-stage kidney disease (ESKD) resulting in nephrotic proteinuria and renal failure, but the treatment options are limited to dialysis and renal transplantation. So there is an urgent need for renal regenerative therapies. Generation of podocytes from human stem cells is regarded as a promising therapeutic strategy to repair or regenerate the damaged kidneys; however, the reliable induction system remains a challenge. In this study, we established a two-stage induction protocol for podocyte generation from human adipose-derived mesenchymal stem cells (hAD-MSCs). We initially established a condition that induces hAD-MSCs toward intermediate mesoderm cells with activin A and high concentration of retinoic acid (RA). Subsequently, by using the combination of activin A and low concentration of RA and BMP7, we generated podocyte-like cells expressing multiple podocyte-specific markers and able to integrate into a developing nephron of embryonic kidney explant culture and ameliorate proteinuria and kidney injure in adriamycin-treated mice. Furthermore, we identified that miRNA-498 inhibitor has potential to improve the differentiation of hAD-MSCs into podocyte-like cells and established a robust induction protocol. Thereby, our study advocated an efficient method for the induction of kidney podocyte-like (iPod) cells from hAD-MSCs and provided an ideal candidate for regenerative therapies of the kidney.

A Road to Chronic Kidney Disease: Toward Glomerulosclerosis via Dendrin

This commentary highlights the article by Weins etal that describes a potential mechanism to delay the onset and progression of end-stage kidney disease.