Cause Of End-stage Kidney Disease Research Articles

Effect of altitude on mortality of end-stage renal disease patients on hemodialysis in Peru.

BackgroundIn Latin America, the prevalence of end-stage kidney disease (ESKD) has risen tremendously during the last decade. Previous studies have suggested that receiving dialysis at high altitude confers mortality benefits; however, this effect has not been demonstrated at >2000 m above sea level (masl) or in developing countries.MethodsThis historical cohort study analyzed medical records from six Peruvian hemodialysis (HD) centers located at altitudes ranging from 44 to 3827 masl. Adult ESKD patients who started maintenance HD between 2000 and 2010 were included. Patients were classified into two strata based on the elevation above sea level of their city of residence: low altitude (<2000 masl) and high altitude (≥2000 masl). Death from any cause was collected from national registries and Cox proportional hazards models were built.ResultsA total of 720 patients were enrolled and 163 (22.6%) resided at high altitude. The low-altitude group was significantly younger, more likely to have diabetes or glomerulonephritis as the cause of ESKD and higher hemoglobin. The all-cause mortality rate was 84.3 per 1000 person-years. In the unadjusted Cox model, no mortality difference was found between the high- and low-altitude groups {hazard ratio [HR] 1.20 [95% confidence interval (CI) 0.89–1.62]}. After multivariable adjustment, receiving HD at high altitude was not significantly associated with higher mortality, but those with diabetes as the cause of ESKD had significantly higher mortality [HR 2.50 (95% CI 1.36–4.59)].ConclusionsIn Peru, patients receiving HD at high altitudes do not have mortality benefits.

Noncoding RNAs in Diabetic Nephropathy: Pathogenesis, Biomarkers, and Therapy.

The correlation between diabetes and systematic well-being on human life has long established. As a common complication of diabetes, the prevalence of diabetic nephropathy (DN) has been increasing globally. DN is known to be a major cause of end-stage kidney disease (ESKD). Till now, the molecular mechanisms for DN have not been fully explored and the effective therapies are still lacking. Noncoding RNAs are a class of RNAs produced by genome transcription that cannot be translated into proteins. It has been documented that ncRNAs participate in the pathogenesis of DN by regulating inflammation, apoptosis, autophagy, cell proliferation, and other pathological processes. In this review, the pathological roles and diagnostic and therapeutic potential of three types of ncRNAs (microRNA, long noncoding RNA, and circular RNA) in the progression of DN are summarized and illustrated.

Significance of SGLT2 inhibitors: lessons from renal clinical outcomes in patients with type 2 diabetes and basic researches.

Diabetic kidney disease (DKD), a microvascular complication of diabetes, has been the leading cause of end-stage kidney disease (ESKD). Accordingly, patients with type 2 diabetes mellitus (T2DM) develop renal damage due to multiple metabolic and cardiorenal disease-related risk factors, including hyperglycemia, hypertension, dyslipidemia, hyperuricemia, and overnutrition/obesity. Despite multifactorial management including the administration of renin-angiotensin system inhibitors, patients often do not experience sufficient suppression of DKD progression and, thus, remain at risk for ESKD. Recent studies on cardiovascular outcomes among patients with T2DM have clearly shown that sodium-glucose cotransporter 2 (SGLT2) inhibitors, such as empagliflozin, canagliflozin, and dapagliflozin, have cardiorenal protective effects apart from their glucose-lowering effects. In particular, SGLT2 inhibitors have been found to improve renal outcomes, including ESKD, by slowing renal function decline and reducing urinary albumin excretion through their class effect. The proposed mechanisms for the renoprotective effects of SGLT2 inhibitors include the action of tubulo-glomerular feedback system and attenuation of hypoxia and metabolic stress in proximal tubular cells mediated through the inhibition of excessive glucose and sodium reabsorption, increased erythropoiesis, or increased ketone body production.

P0408KIDNEY TRANSPLANTATION OUTCOMES IN PATIENTS WITH IGA NEPHROPATHY IN THE MODERN ERA OF IMMUNOSUPPRESSION: A CASE CONTROL STUDY

Abstract Background and Aims Advances in immunosuppressants, used for kidney transplantation (KTx) have significantly improved outcomes in this field. We aimed to compare the long-term results of KTx in recipients with IgAN, as cause of end stage kidney disease (ESKD), with those of patients, with non-glomerular causes of renal failure, during the modern era of immunosuppression for KTx. Method This is a retrospective, case control study, in which were included patients who received a KTx after 2000. Patients were eligible to be included, if they had IgAN in a native kidney biopsy specimen and follow up longer than 1 year after KTx. IgAN patients were compared to a control-group of patients with non-glomerular primary causes of ESKD matched for age, gender, date of KTx and donor source. Graft biopsies were performed by clinical indication. Patients with ABO incompatible KTx, preemptive KTx, re-KTx, PRA&amp;gt;50%, major surgical complications during the 1st post-KTx month or non-compliance were excluded from the analysis of outcome. Primary outcomes of interest included graft function, patient and graft survival at end of follow up. The rate of IgAN recurrence in the graft and its impact in renal function and survival were also recorded. Computed GFR was calculated using the Modification of Diet in Renal Disease formula. Results A total of 102 KTx recipients with biopsy-proven IgAN, were compared to 204 controls with non-glomerular causes of ESKD. The mean age of patients with IgAN was 43.2(±10.15) years and 68(66.7%) were men. The mean time in dialysis was 50.2(±48.7) months and 59(57.8%) of them received a graft from a living donor. The mean cold ischemia time was 17.5(±6.7) hours, while 22(21.6%) of patients experienced delayed graft function. 97.05% of patients received induction therapy with an anti-CD25 inhibitor and 99.3% were maintained with a triple immunosuppressive regimen consisted of a mycophenolate mofetil formulation, a calcineurin inhibitor and glucocorticoids. The mean serum creatinine and eGFR at end of follow up were significantly lower for the IgAN group (p=0.001 and p=0.02 respectfully) with no difference in the frequency of acute rejection. However, graft and patient survival were not different even after controlling for follow up longer than one decade. During a mean follow up time of 120.8(±49.1) months, IgAN recurrence in the graft was documented in 23(22.5%) patients. The mean time to recurrence was 47.8(41.8) months, with a mean serum creatinine 1.83(±0.52) mg/dl and eGFR of 43.45(±18.4) ml/min/1.73m2 at the end of follow up. Within the IgAN group, although graft function was significantly lower in patients with disease recurrence, compared with that of patients without recurrence (p=0.003), graft loss remained not different between these two subgroups (p=0.49). Conclusion In the newer era of immunosuppression, long-term outcomes of KTx in patients with IgAN, as primary disease, appear significantly improved, and although graft function was significantly lower in patients with IgAN at the end of follow up, graft and patient survival was not different, compared to patients with non-glomerular causes of ESKD. Recurrence of IgAN in the graft was documented in 22.5% of patients and was associated with significantly lower eGFR at end of follow up compared to patients without recurrence but it did not impact graft survival in this time period.

P1713A CASE OF DEVASTATING BARIATRIC SURGERY-RELATED ACUTE OXALATE NEPHROPATHY FIRST DIAGNOSED AFTER KIDNEY TRANSPLANTATION

Abstract Background and Aims Despite the obvious efficacy in achieving weight loss, traditional malabsorptive procedures (intestinal by-pass) used for the treatment of obesity, may be associated with enteric oxaluria. Enteric oxaluria, by causing calcium-oxalate stones and nephrocalcinosis, represents an under-recognized cause of end-stage kidney disease in patients with history of intestinal by-pass. Herein, we describe a patient with a long-standing history of intestinal by-pass who developed a devastating acute oxalate nephropathy first diagnosed after kidney transplantation. Method A white female aged 50, who started hemodialysis one year earlier because of tubule-interstitial nephritis on a kidney biopsy, and who had history of recurrent kidney stones (calcium oxalate), underwent urgent deceased-donor kidney transplantation because of exhausted vascular access for hemodialysis (tunneled CVC right giugular vein as the last resort). She had received intestinal by-pass surgery 20 yrs earlier, and had a pacemaker implantation in the left sublavian vein for AV block two years earlier. She was highly sensitized because of blood transfusions at the time of surgery. Results After transplantation, graft function had immediate recovery, serum creatinine decreasing to 2.0mg/dL (117 mmol/L) on post-operative day (POD) 3. Shortly after, serum creatinine started rising until it reached 4.0mg/dL (354mmol/L) on POD 5. Three graft biopsies (performed on POD 6, 9 and 15 post-transplant) revealed acute oxalate nephropathy ( Figure1-2 large oxalate crystals on fresh unfixed core of kidney tissue analyzed under bright field microscope using polarized light) with no sign of rejection. Serial monitoring of Luminex SAB did not reveal circulating anti-HLA donor specific antibodies. Fundus examination revealed two tiny mono-lateral retinal oxalate deposits, whereas bone biopsy did not reveal oxalate accumulation. Plasma oxalate levels were 43 mmol/L on POD 10 were urinary oxalate excretion was 29mg /day on POD 14. The patient slowly progressed to end-stage kidney disease 2-month post-transplantation despite daily high flux dialysis since POD 7, fat-free and oxalate-free diet, oral potassium and high dose pyridoxine supplements. Conclusion Patients on chronic dialysis with a previous history of bariatric surgery via intestinal by-pass may have oxalate nephropathy caused by enteric oxaluria as unknown primary renal disease. The disease may recur shortly after transplantation despite the adoption of prompt aggressive treatment for oxalate removal.

P0967ENHANCING PODOCYTE REGENERATION WITH BROMOINDIRUBIN-3´-OXIME (BIO) AS A POTENTIAL TERAPEUTIC TARGET IN DIABETIC KIDNEY DISEASE

Abstract Background and Aims Diabetic nephropathy (DN) is a leading cause of end-stage kidney disease. RAS and SGLT2 inhibitors are well established in reducing the progression of DN in early stages but true tissue regeneration is not achieved. BIO, a glucose synthase kinase 3 inhibitor (GSK3β), improves outcomes in non-diabetic kidney injury by enhancing podocyte regeneration from local podocyte progenitors. We hypothesized that treating podocytes in hyperglycemic conditions with BIO could revert the oxidative stress damage typically seen in DN. Method To study the effect of BIO on podocytes, we isolated glomeruli from wildtype mice by perfusing them with magnetic beads and stimulated the purified glomeruli for 24 hours with or without 10µM BIO in presence or absence of 30mM glucose. The response to the stimuli was assessed by characterizing the overall gene expression via RT-qPCR. Additionally, differentiated murine podocytes (K5P5) and murine glomerular endothelial cells (GEnCs) were stimulated under the same conditions with the same subsequent readouts to differentiate the response of podocytes from that of the endothelial compartment. To understand, if BIO could represent a potential new therapeutic option under the aspect of pharmacological safety, we uninephrectomized male BKS-Lepr-/- mice, fed them with a salt-free chow to induce DN. To mimic the human condition more closely we treated the mice with and without BIO, but in presence of the human standard of care therapy (SOC; metformin, ramipril, empagliflozin), which could potentially identify adverse pharmacological interactions. After 16 weeks kidney, heart, pancreas, sciatic nerve, liver, blood, skeletal muscle and adipose tissue were collected for histopathological and gene expression analysis. Results While glucose exposure induced a strong reduction of nephrin gene expression in whole glomeruli, BIO reverted the effect, indicating a protective effect on podocytes (30 mM glucose: 0.447, ci 0.224 – 0.724; 30 mM glucose+BIO: 1.837, ci 1.205 – 2.505, p-value=0.029, Fig.A). Similar results were found in differentiated murine podocytes, in which BIO treatment significantly increased podocin gene expression after 7 days of culture (0.920, ci 0.820 – 1.34, 3.561 ci 1.756 – 7.909, p-value=0.029), also here suggesting a protective effect of BIO on glucose-induced podocyte (Fig.B). In contrast, BIO showed no effect on endothelial cell-specific markers in murine GEnCs, indicating a podocyte-specific effect of BIO. A comparable effect of BIO on podocytes was observed in vivo, as well. Diabetic mice treated with SOC and BIO showed borderline increased renal podocin gene expression levels (2.177 ci 0.830 – 2.739) compared to SOC alone (1.188 ci 0.378 – 2.194 ,p-value = 0.064), but did not modify markers of inflammation, such as IL-6, or fibrosis, such as fibronectin (Fig.C). The extended safety analysis of non-renal organs did not reveal any safety concern of the SOC/BIO combination in comparison to SOC alone in any of the analyzed tissues. Conclusion The current study revealed that BIO has protective effects on podocytes in vitro and might as well have renoprotective effects in DN in vivo by enhancing podocyte regeneration without showing any safety-related issues.

P0719SRC KINASES AGGRAVATE DIABETIC KIDNEY INJURY THROUGH ACTIVATION OF ENDOPLASMIC RETICULUM STRESS

Abstract Background and Aims Diabetic kidney disease (DKD) is the major cause of end-stage kidney disease which is characterized by prominent kidney fibrosis. Src family kinases (SFKs), a family of proto-oncogenes, has been acknowledged to mediate the development of kidney fibrosis. While, several studies in liver and skeletal muscle suggested the role of Src kinases in activating endoplasmic reticulum (ER) stress. The present study aimed to investigate the mechanism of Src kinases-ER stress in mediating the progression of DKD. Method Type 1 diabetes was induced by a single 60 mg/kg i.p injection of streptozotocin (STZ) in 7-week-old male, Sprague-Dawley rats. Diabetic rats received 8-week-treatment of either KF-1607 (30 mg/kg/day), a pharmacological inhibitor of SFKs, or losartan (1 mg/kg/day), a standard treatment for patients with DKD. Results Among SFKs, Fyn and Lyn kinases were particularly increased in the diabetic kidney. Inhibition of Src kinases by KF-1607 improved kidney function and inhibited tubular injury, presented by decreased serum creatinine, albuminuria, and urinary KIM-1 excretion. Pathological changes in the kidney, such as enhanced glomerular volume, tuft area, and fractional mesangial area, were ameliorated in KF-treated rats. Highly-accumulated collagen network as well as increased TGF-β and α-SMA mRNA levels in the diabetic kidney were also significantly reduced in response to KF treatment. Furthermore, it consistently attenuated kidney inflammation and oxidative stress. The renoprotective effects of KF were interestingly similar to those of losartan. We showed increases in protein levels of phosphorylated IRE-1α, ATF6, GRP78 as well as CHOP indicating an exacerbated ER stress in the diabetic kidney. These ER stress markers were significantly decreased in KF treated mice. Conclusion Altogether, Src kinases through activation of ER stress aggravates kidney injury in STZ-induced diabetic rats.

Effect of Guanxin Danshen Formulation on diabetic kidney disease in db/db mice through regulation of Nrf2 pathway

Diabetic kidney disease(DKD) has become a primary cause of end-stage kidney disease, without any effective treatment available. In this study, we assessed the protective effect of Guanxin Danshen Formulation(GXDSF) on diabetic nephropathy in db/db mice. The db/m and db/db mice were randomly divided into 4 groups: control group, model group, metformin group, and GXDSF group. After 8 weeks' treatment with GXDSF, metformin or normal saline, the mice were sacrificed, and the blood and kidney tissues were collected for the further analysis. Compared with the model group, TG, TCH and LDL levels significantly decreased in the GXDSF group. The results from HE and PAS staining showed that db/db mice exhibited abnormal kidney tissues with increased glomerular volume, basement-membrane thickening and mesangial cell proliferation, which could be significantly alleviated by GXDSF treatment. GXDSF treatment also reduced serum creatinine and BUN. Meanwhile, GXDSF treatment markedly elevated GSH-PX levels, while reduced LDH and MDA levels in the kidney tissues. Western blot assay showed that GXDSF evidently up-regulated protein levels of ERα and p-Akt, and subsequently promoted HO-1 expression mediated by Nrf2. These data collectively indicated that GXDSF protects db/db mice against DN by regulating ERα and Nrf2-mediated HO-1 expression.

Clinical and genetic spectra of autosomal dominant tubulointerstitial kidney disease due to mutations in UMOD and MUC1

Autosomal dominant tubulointerstitial kidney disease (ADTKD) is an increasingly recognized cause of end-stage kidney disease, primarily due to mutations in UMOD and MUC1. The lack of clinical recognition and the small size of cohorts have slowed the understanding of disease ontology and development of diagnostic algorithms. We analyzed two registries from Europe and the United States to define genetic and clinical characteristics of ADTKD-UMOD and ADTKD-MUC1 and develop a practical score to guide genetic testing. Our study encompassed 726 patients from 585 families with a presumptive diagnosis of ADTKD along with clinical, biochemical, genetic and radiologic data. Collectively, 106 different UMOD mutations were detected in 216/562 (38.4%) of families with ADTKD (303 patients), and 4 different MUC1 mutations in 72/205 (35.1%) of the families that are UMOD-negative (83 patients). The median kidney survival was significantly shorter in patients with ADTKD-MUC1 compared to ADTKD-UMOD (46 vs. 54 years, respectively), whereas the median gout-free survival was dramatically reduced in patients with ADTKD-UMOD compared to ADTKD-MUC1 (30 vs. 67 years, respectively). In contrast to patients with ADTKD-UMOD, patients with ADTKD-MUC1 had normal urinary excretion of uromodulin and distribution of uromodulin in tubular cells. A diagnostic algorithm based on a simple score coupled with urinary uromodulin measurements separated patients with ADTKD-UMOD from those with ADTKD-MUC1 with a sensitivity of 94.1%, a specificity of 74.3% and a positive predictive value of 84.2% for a UMOD mutation. Thus, ADTKD-UMOD is more frequently diagnosed than ADTKD-MUC1, ADTKD subtypes present with distinct clinical features, and a simple score coupled with urine uromodulin measurements may help prioritizing genetic testing.

A common glomerular transcriptomic signature distinguishes diabetic kidney disease from other kidney diseases in humans and mice

BackgroundCurrent uncertainties about the similarity between human diseases and their experimental models are hampering the development of new therapies. This is especially the case for diabetic kidney disease (DKD), the most common cause of end-stage kidney disease. To better understand the nature of the commonality between humans and their mouse models, we posed the question: in diabetic kidney disease are transcriptional profiles primarily disease-specific or species-specific? MethodsWe performed a meta-comparison of the glomerular transcriptomic characteristics of 133 human and 66 mouse samples including five human kidney diseases and five mouse models, validating expression patterns of a central node by immunohistochemistry. FindingsPrincipal component analysis controlled for mouse background, revealed that gene expression changes in glomeruli from humans with DKD are more similar to those of diabetic mice than they are to other human glomerular diseases. This similarity enabled the construction of a discriminatory classifier that distinguishes diabetic glomeruli from other glomerular phenotypes regardless of their species of origin. To identify where the commonality between mice and humans with diabetes lies, networks of maximally perturbed protein interactions were examined, identifying a central role for the epidermal growth factor receptor (EGFR). By immunohistochemical staining, we found EGFR to be approximately doubled in its glomerular expression in both humans and mice. InterpretationThese findings indicate that diabetic mouse models do mimic some of the features of human kidney disease, at least with respect to their glomerular transcriptomic signatures, and they identify EGFR as being a central player in this inter-species overlap.

Incidence of ESKD Among Native Hawaiians and Pacific Islanders Living in the 50 US States and Pacific Island Territories

Native Hawaiians and Pacific Islanders (NHPI) have been reported to have the highest rates of incident end-stage kidney disease (ESKD) compared with other races in the United States. However, these estimates were likely biased upward due to the exclusion of nearly half the NHPI population that reports multiple races in the US Census. We sought to estimate the incidence rate of ESKD, including individuals reporting multiple races, and describe the clinical characteristics of incident cases by race and location. Health care database study. US residents of the 50 states and 3 Pacific Island territories of the United States whose ESKD was recorded in the US Renal Data System (USRDS) between 2007 and 2016, as well as US residents recorded in the 2010 Census. Age, sex, race, body mass index, primary cause of ESKD, comorbid conditions, estimated glomerular filtration rate, pre-ESKD nephrology care, and hemoglobin A1c level among ESKD cases. Initiation of maintenance dialysis or transplantation for kidney failure. Crude ESKD incidence rates (cases/person-years) were estimated using both single- and multiple-race reporting. Even after inclusion of multirace reporting, NHPI had the highest ESKD incidence rate among all races in the 50 states (921 [95% CI, 904-938] per million population per year)-2.7 times greater than whites and 1.2 times greater than blacks. Also using multirace reporting, the NHPI ESKD incident rate in the US territories was 941 (95% CI, 895-987) per million population per year. Diabetes was listed as the primary cause of ESKD most frequently for NHPI and American Indians/Alaska Natives. Sensitivity analysis adjusting for age and sex demonstrated greater differences in rates between NHPI and other races. Diabetes was the primary cause of ESKD in 60% of incident NHPI cases. Patients with ESKD living in the territories had received less pre-ESKD nephrology care than had patients living in the 50 states. Different methods of race classification in the USRDS versus the US Census. NHPI living in the 50 US states and Pacific territories had the highest rates of ESKD incidence compared with other races. Further research and efforts are required to understand the reasons for and define how best to address this racial disparity.

IGF-1 and HGF Preconditioning of Bone Marrow Mesenchymal Stem Cells Reduced Proteinuria in Rat Focal Segmental Glomerulosclerosis Model

Background & Aim Focal Segmental Glomerulosclerosis (FSGS) is one of the leading causes of end-stage kidney disease requiring renal replacement therapy for survival. It is characterized by massive proteinuria that results in hypoalbuminemia, edema and hyperlipidemia. and is known as irreversible kidney disease that steroid-based drugs only slow down the progression. The use of Mesenchymal stem cells (MSCs) has been successful in the treatment of glomerular diseases. The biggest challenge of the MSC application is its engraftment into the site of injury and its loss due to the poor microenvironment. Preconditioning of MSCs by particular growth factors such as insulin-like growth factor-1 (IGF-1) and hepatocyte growth factor (HGF) increases their migration, immunomodulation and survival. IGF-1 and HGF have been proposed as promising therapeutic agents in recent years and are especially preferred in renal diseases with their renotrophic and nephroprotective effects. Therefore we aimed to test the effect of IGF-1 and HGF-preconditioned MSCs in a rat model of FSGS. Methods, Results & Conclusion Preconditioning of MSCs was performed by 10 ng/ml IGF-1 and 20 ng/ml HGF and designated as iMSCs. Rat (Sprague-Dawley) FSGS model was technically induced by a single-dose intraperitoneal administration of Puromycin Aminonucleoside (PAN) (150 mg/kg). There were PBS, MSC and iMSC treatment groups (n=6/gr77). The occurrence of FSGS was assessed by biochemistry (i.e. elevated urinary protein/creatinine (P/C) ratio), immunohistochemistry (i.e. decreased glomerular SYNPO protein level) and electron microscopy (i.e. presence of podocyte effacement). We applied 2 × 105 MSC or preconditioned MSC intravenously on the day of 4 following PAN administration. The effect of treatment was assessed by urinary P/C ratios in 24-hour urine which was collected on the treatment day of 9. iMSC treatment significantly decreased proteinuria (p As a result of our study, we demonstrated that iMSCs can partially reverse the glomerular damage and reduce proteinuria with regenerating glomerular filtering apparatus in the PAN model of FSGS and therefore may offer a new therapeutic strategy for human FSGS.

Associations between diabetes and sex with peritoneal dialysis technique and patient survival: Results from the Australia and New Zealand Dialysis and Transplant Registry cohort study.

A differential association between mortality and cause of end-stage kidney disease in patients with type 2 diabetes mellitus (T2DM) has been shown. Sex-specific differences in diabetes-related complications have been described. It is unclear whether sex affects the associations between diabetes and peritoneal dialysis (PD) technique and patient survival. Using the Australia and New Zealand Dialysis and Transplant Registry, we examined a two-way interaction between sex and diabetes status (no diabetes, T2DM and non-diabetic nephropathy [T2DM + non-DN] and T2DM and diabetic nephropathy [T2DM + DN]) for PD technique failure (including death), all-cause mortality and cause-specific mortality in incident adult PD patients between 1996 and 2016 using adjusted Cox regression. Mediation analysis was conducted to determine whether peritonitis was a mediator in these associations. In 8279 PD patients, those with T2DM + DN had the greatest risks in technique failure, all-cause mortality and cause-specific mortality followed by patients with T2DM + non-DN, then patients without diabetes. Sex modified the association with diabetes status in technique failure (pinteraction = 0.001) and cardiac mortality (pinteraction = 0.008). In women with T2DM + DN, the adjusted hazard ratio (HR) for technique failure was 1.45 (1.30-1.62) and was higher than men with T2DM + DN (1.17 [1.08-1.28]; referent: no diabetes). In women with T2DM + DN, the adjusted HR for cardiac mortality was 2.12 (1.73-2.61) and was also higher than men with T2DM + DN (1.66 [1.43-1.95]). Less than 10 % of the effect between diabetes and PD technique failure or mortality was mediated by peritonitis. PD patients with diabetic nephropathy had increased risk of PD technique failure and mortality, with the magnitude of these risks greater in women.

CREDENCE: Significant Victory for Diabetic Kidney Disease

Diabetic kidney disease (DKD), the most common cause of end-stage kidney disease (ESKD), has significant morbidity and mortality, particularly from cardiovascular complications. The CREDENCE (canagliflozin and renal events in diabetes with established nephropathy clinical evaluation) trial reported by Perkovic and collaborators has led to an emergence of a new class of therapeutic agents for slowing DKD progression.

An updated overview of diabetic nephropathy: Diagnosis, prognosis, treatment goals and latest guidelines.

Diabetic nephropathy (DN) is a major healthcare challenge. It occurs in up to 50% of those living with diabetes, is a major cause of end-stage kidney disease (ESKD) that requires treatment with dialysis or renal transplantation, and is associated with significantly increased cardiovascular morbidity and mortality. DN is a clinical syndrome characterized by persistent albuminuria and a progressive decline in renal function, but it is increasingly recognized that the presentation and clinical course of kidney disease in diabetes is heterogeneous. The term diabetic kidney disease (DKD) is now commonly used to encompass the spectrum of people with diabetes who have either albuminuria or reductions in renal function. In this article, the clinical presentation and approach to diagnosis of DKD will be discussed, as will its prognosis. The general principles of management of DKD will also be reviewed with reference to current international guidelines.

Inflammation-like changes in the urothelium of Lifr-deficient mice and LIFR-haploinsufficient humans with urinary tract anomalies.

Congenital anomalies of the kidney and urinary tract (CAKUT) are the most common cause of end-stage kidney disease in children. While the genetic aberrations underlying CAKUT pathogenesis are increasingly being elucidated, their consequences on a cellular and molecular level commonly remain unclear. Recently, we reported rare heterozygous deleterious LIFR variants in 3.3% of CAKUT patients, including a novel de novo frameshift variant, identified by whole-exome sequencing, in a patient with severe bilateral CAKUT. We also demonstrated CAKUT phenotypes in Lifr-/- and Lifr+/- mice, including a narrowed ureteric lumen due to muscular hypertrophy and a thickened urothelium. Here, we show that both in the ureter and bladder of Lifr-/- and Lifr+/- embryos, differentiation of the three urothelial cell types (basal, intermediate and superficial cells) occurs normally but that the turnover of superficial cells is elevated due to increased proliferation, enhanced differentiation from their progenitor cells (intermediate cells) and, importantly, shedding into the ureteric lumen. Microarray-based analysis of genome-wide transcriptional changes in Lifr-/- versus Lifr+/+ ureters identified gene networks associated with an antimicrobial inflammatory response. Finally, in a reverse phenotyping effort, significantly more superficial cells were detected in the urine of CAKUT patients with versus without LIFR variants indicating conserved LIFR-dependent urinary tract changes in the murine and human context. Our data suggest that LIFR signaling is required in the epithelium of the urinary tract to suppress an antimicrobial response under homeostatic conditions and that genetically induced inflammation-like changes underlie CAKUT pathogenesis in Lifr deficiency and LIFR haploinsufficiency.

The positive effect of selective prostaglandin E2 receptor EP2 and EP4 blockade on cystogenesis in vitro is counteracted by increased kidney inflammation in vivo

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a major cause of end-stage kidney disease in man. The central role of cyclic adenosine monophosphate (cAMP) in ADPKD pathogenesis has been confirmed by numerous studies including positive clinical trial data. Here, we investigated the potential role of another major regulator of renal cAMP, prostaglandin E2 (PGE2), in modifying disease progression in ADPKD models using selective receptor modulators to all four PGE2 receptor subtypes (EP1-4). In 3D-culture model systems utilizing dog (MDCK) and patient-derived (UCL93, OX161-C1) kidney cell lines, PGE2 strikingly promoted cystogenesis and inhibited tubulogenesis by stimulating proliferation while reducing apoptosis. The effect of PGE2 on tubulogenesis and cystogenesis in 3D-culture was mimicked or abolished by selective EP2 and EP4 agonists or antagonists but not those specific to EP1 or EP3. In a Pkd1 mouse model (Pkd1nl/nl), kidney PGE2 and COX-2 expression were increased by two-fold at the peak of disease (week four). However, Pkd1nl/nl mice treated with selective EP2 (PF-04418948) or EP4 (ONO-AE3-208) antagonists from birth for three weeks had more severe cystic disease and fibrosis associated with increased cell proliferation and macrophage infiltration. A similar effect was observed for the EP4 antagonist ONO-AE3-208 in a second Pkd1 model (Pax8rtTA-TetO-Cre-Pkd1f/f). Thus, despite the positive effects of slowing cyst growth invitro, the more complex effects of inhibiting EP2 or EP4 invivo resulted in a worse outcome, possibly related to unexpected pro-inflammatory effects.

Smad4 promotes diabetic nephropathy by modulating glycolysis and OXPHOS.

Diabetic nephropathy (DN) is the leading cause of end-stage kidney disease. TGF-β1/Smad3 signalling plays a major pathological role in DN; however, the contribution of Smad4 has not been examined. Smad4 depletion in the kidney using anti-Smad4 locked nucleic acid halted progressive podocyte damage and glomerulosclerosis in mouse type 2 DN, suggesting a pathogenic role of Smad4 in podocytes. Smad4 is upregulated in human and mouse podocytes during DN. Conditional Smad4 deletion in podocytes protects mice from type 2 DN, independent of obesity. Mechanistically, hyperglycaemia induces Smad4 localization to mitochondria in podocytes, resulting in reduced glycolysis and oxidative phosphorylation and increased production of reactive oxygen species. This operates, in part, via direct binding of Smad4 to the glycolytic enzyme PKM2 and reducing the active tetrameric form of PKM2. In addition, Smad4 interacts with ATPIF1, causing a reduction in ATPIF1 degradation. In conclusion, we have discovered a mitochondrial mechanism by which Smad4 causes diabetic podocyte injury.

The Australian Calciphylaxis Registry: reporting clinical features and outcomes of patients with calciphylaxis.

Calciphylaxis is a rare disease, predominantly affecting patients with chronic kidney disease (CKD) and associated with significant morbidity and mortality due to progressive cutaneous calcification, necrotic ulceration and infection. Clinical registries have been established to better understand the risk factors, optimal treatments and disease outcomes of calciphylaxis. We established a prospective, Internet-based clinical registry for the online notification of calciphylaxis cases in Australia. Seven institutions participated, with data recorded on patient characteristics, biochemical parameters, treatments and disease outcomes. Between 2014 and 2019, 47 cases of calciphylaxis were registered. The mean patient age was 66 ± 11 years and body mass index was 35 ± 9 kg/m2, with a higher proportion of females (51%). Eighty-seven percent of patients had end-stage kidney disease (ESKD), with 61% on hemodialysis or hemodiafiltration, with a median dialysis vintage of 4.8 [interquartile range (IQR) 1.7-7.4)] years. Five patients had CKD not requiring dialysis and two were kidney transplant recipients. Diabetes was present in 76% of patients and the cause of ESKD in 60%; 34% received vitamin K antagonists (VKAs) before diagnosis. The median parathyroid hormone level at diagnosis was 32 (IQR 14-50) pmol/L. The most common site of calciphylaxis was the lower limbs (63%), with 19% of patients having more than one area involved. Ten patients (22%) had a resolution of calciphylaxis and 25 died, with 50% mortality at a median of 1.6 (IQR 0.2-2.5) years from diagnosis. The Australian Calciphylaxis Registry highlights risk factors for calciphylaxis, including diabetes, obesity and VKA use. Resolution of calciphylaxis is uncommon despite multimodal therapy and mortality from calciphylaxis in the first year following diagnosis remains high.

SGLT2 inhibitors to prevent diabetic kidney disease

Up to 40% of patients with type 2 diabetes develop diabetic kidney disease, presenting with increased albuminuria (urinary albumin-to-creatinine ratio [UACR]), decreased glomerular filtration rate (GFR), or both. Unfortunately, there is no reliable method to predict who will eventually develop diabetic kidney disease and by the time increased albuminuria or reduction in GFR are detected, the burden of renal and cardiovascular risk is already high. Despite standard recommended care, including optimal control of blood pressure, glucose, and lipids, and use of renin–angiotensin system (RAS) blockade, residual risk of progression remains high in people with type 2 diabetes, and diabetic kidney disease is currently the leading cause of end-stage kidney disease (ESKD) worldwide.