MO262THE SINGLE-CELL TRANSCRIPTOMICS OF HUMAN IGA NEPHROPATHY

Background and Aims The exact molecular mechanisms underlying IgA nephropathy (IgAN) remains incompletely defined. Therefore, it is necessary to further elucidate the mechanism of IgA nephropathy and find novel therapeutic targets. Method Single-cell RNA sequencing (scRNA-seq) was applied to kidney biopsies from 4 IgAN and 1 control subjects to define the transcriptomic landscape at the single-cell resolution. Unsupervised clustering analysis of kidney specimens was used to identify distinct cell clusters. Differentially expressed genes and potential signaling pathways involved in IgAN were also identified. Results Our analysis identified 14 cell subsets in kidney biopsies from IgAN patients, and analyzed changing gene expression in distinct renal cell types. We found increased mesangial expression of several novel genes including MALAT1, GADD45B, SOX4 and EDIL3, which were related to proliferation and matrix accumulation and have not been reported in IgAN previously. The overexpressed genes in tubule cells of IgAN were mainly enriched in inflammatory pathways including TNF signaling, IL-17 signaling and NOD-like receptor signaling. Moreover, the receptor-ligand crosstalk analysis revealed potential interactions between mesangial cells and other cells in IgAN. Specifically, IgAN with overt proteinuria displayed elevated genes participating in several signaling pathways which may be involved in pathogenesis of progression of IgAN. Conclusion The comprehensive analysis of kidney biopsy specimen demonstrated different gene expression profile, potential pathologic ligand-receptor crosstalk, signaling pathways in human IgAN. These results offer new insight into pathogenesis and identify new therapeutic targets for patients with IgA nephropathy.

A Partial Picture of the Single-Cell Transcriptomics of Human IgA Nephropathy

The molecular mechanisms underlying renal damage of IgA nephropathy (IgAN) remain incompletely defined. Here, single-cell RNA sequencing (scRNA-seq) was applied to kidney biopsies from IgAN and control subjects to define the transcriptomic landscape at single-cell resolution. We presented a comprehensive scRNA-seq analysis of human renal biopsies from IgAN. We showed for the first time that IgAN mesangial cells displayed increased expression of several novel genes including MALAT1, GADD45B, SOX4, and EDIL3, which were related to cell proliferation and matrix accumulation. The overexpressed genes in tubule cells of IgAN were mainly enriched in inflammatory pathways including TNF signaling, IL-17 signaling, and NOD-like receptor signaling. Furthermore, we compared the results of 4 IgAN patients with the published scRNA-Seq data of healthy kidney tissues of three human donors in order to further validate the findings in our study. The results also verified that the overexpressed genes in tubule cells from IgAN patients were mainly enriched in inflammatory pathways including TNF signaling, IL-17 signaling, and NOD-like receptor signaling. The receptor-ligand crosstalk analysis revealed potential interactions between mesangial cells and other cells in IgAN. IgAN patients with overt proteinuria displayed elevated genes participating in several signaling pathways compared with microproteinuria group. It needs to be mentioned that based on number of mesangial cells and other kidney cells analyzed in this study, the results of our study are preliminary and needs to be confirmed on larger number of cells from larger number of patients and controls in future studies. Therefore, these results offer new insight into pathogenesis and identify new therapeutic targets for IgAN.

Outcome of atypical haemolytic uraemic syndrome relapse after eculizumab withdrawal

Background The introduction of eculizumab has significantly improved the outcome of patients with atypical haemolytic uraemic syndrome (aHUS). Because of the risk of relapse after discontinuation, eculizumab was proposed as life-long therapy. However, data on the outcome of relapse are limited. In the Netherlands, patients with aHUS are treated with a restrictive eculizumab regime and are included in a national observational study (CUREiHUS, Dutch Trial Register NTR5988/NL5833). Methods For this interim safety analysis, we evaluated the outcome of all adult patients with a suspected relapse, defined as the need to intensify eculizumab after tapering or withdrawal of therapy. Results We describe 11 patients who received renewed eculizumab therapy because of suspected relapse. In three patients with aHUS in native kidneys, estimated glomerular filtration rate (eGFR) returned to baseline value and remained stable without overt proteinuria after follow-up. Six out of eight transplanted patients responded to eculizumab therapy with improvement in eGFR. After a median follow-up of 24.6 months, a reduction of eGFR ≥25% was observed in three of these transplanted patients, which was attributed to the aHUS relapse in only one patient. Conclusions This interim analysis suggests that re-treatment with eculizumab after relapse is safe and feasible. We will continue to use our restrictive treatment strategy.

A Case Demonstrating the Pathological Relationship between Granulomatous Vasculitis and Glomerular Lesion in Renal Sarcoidosis

We experienced a rare case of tubulointerstitial angiocentric granulomatous vasculitis with focal segmental glomerulosclerosis (FSGS) and associated sarcoidosis. Our patient was an 18-year-old man who presented with exertional cough and dyspnea. He also had overt proteinuria (3.0 g/24 h), normal renal function (eGFR 95 mL/min/1.73 m²), heart failure, and hypertension. He had no previous episode of hypertension. These manifestations immediately improved after the administration of antihypertensive therapy that contained an angiotensin-converting enzyme inhibitor, calcium antagonists, beta antagonists, and diuretics. However, he, later on, developed renal dysfunction, with worsening of both proteinuria and hypertension. Renal biopsy was performed and showed epithelioid cells that were arranged concentrically around small blood vessels in tubulointerstitial granulomas. In the glomeruli, the segmental sclerotic lesions were classified as a perihilar variant of FSGS. There were no inflammatory changes, such as a mesangial lesion, inflammatory cell infiltration, fibrinoid necrosis, or crescent formation, and no glomerular granuloma. In the tubulointerstitial granulomas, the intimal elastic lamina of the interlobular arteries was reduplicated, and the intimal wall thickness of renal arterioles was remarkable. After receiving oral prednisolone therapy, the overt proteinuria resolved, the eGFR recovered from 39.4 to 60.6 mL/min/1.73 m², and hypertension was managed more easily. Thereafter, he did not experience any recurrence. The concurrent improvement of renal function and proteinuria by steroid treatment suggested a relationship between the glomerular lesions and the tubulointerstitial granulomatous vasculitis with associated sarcoidosis.

Comparison of Effects of ACEIs and ARBs on Albuminuria and Hyperkalemia in Indonesian Hypertensive Type 2 Diabetes Mellitus Patients

Purpose. Due to economic consideration, Indonesia’s formulary restrictions are at odds with the treatment guidelines of the American Diabetes Association (ADA) and the Eighth Joint National Committee (JNC 8). ADA and JNC 8 equally recommend the prescription of an angiotensin-converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) for hypertensive patients with type 2 diabetes mellitus (T2DM) with overt proteinuria (urine albumin to creatinine ratio (UACR) ≥ 300 mg/g creatinine). However, since 1 April 2018, Indonesian formulary restricted telmisartan and valsartan only for T2DM patients with declined renal function as shown by eGFR value. There is no compelling evidence in favor of ACEI over ARB or vice versa except for data supporting the early use of both drugs in patients with overt proteinuria. However, ARB is a choice if ACEI’s side effects, that is, coughing, occurs. Therefore, it necessitates a detailed evaluation of the effects of ACEIs and ARBs on albuminuria and their side effect, hyperkalemia, specific to Indonesian T2DM patients. Methods. This cross-sectional study involved 134 T2DM patients whose treatment was restricted to either ACEIs (n = 57) or ARBs (n = 77) for at least two months before the study during May–October 2018. Patients with known end-stage renal disease and those receiving dialysis were excluded. UACR and blood potassium levels were compared between the two study groups. Also, the risk factors of albuminuria and hyperkalemia were estimated using multivariate analysis. Results. T2DM patients in the ACEI and ARB groups had similar characteristics except for a higher body mass index (p=0.008), lower glomerular filtration rate (p=0.04), and a longer duration of prior treatment (p<0.001) in the ARB group. This study showed no differences between the ACEI and ARB groups in the proportion of cases with albuminuria (p=0.97) and hyperkalemia (p=0.86), even after adjustment for confounders. In addition, uncontrolled diastolic blood pressure was a significant factor associated with albuminuria (OR: 4.897, 95% CI: 1.026–23.366; p=0.046), whereas a female was 70.1% less likely to develop hyperkalemia than a male (OR: 0.299, 95% CI: 0.102–0.877; p=0.028). Conclusion. This cross-sectional study demonstrated that ACEIs and ARBs have a similar effect on albuminuria and hyperkalemia in Indonesian hypertensive T2DM patients, even after correction for potentially confounding variables.

P0713DIFFERENTIAL PREDICTION OF DECLINE IN GFR IN PROTEINURIC VS NON-PROTEINURIC DIABETIC PATIENTS

Background and Aims Diabetes mellitus (DM) is known to cause a progressive loss in renal function in at leaset 2 types of clinical presentation: classical diabetic nephropathy with overt proteinuria and non-proteinuric kidney diseases. The mechanisms of the progression should be multifactorial and are considered different at least in some ways in each patient. Now it is important to predict whether each diabetic patient has progressive renal disease or not, hopefully before overt proteinuria appears. Method A hospital-wide study with all the laboratory data for a period of 4 years and 2 months was conducted. A total of 2,804 non-dialysis patients with an age 18 or more in whom the eGFR slope was calculated over 731 days or more with HbA1c measured at least twice were retrieved. Medians were used for each laboratory datum, including dipstick proteinuria and haematuria (both changed to numeric variables, e.g. 1+ into 1.0), blood cell count, serum chemistry, and HbA1c. Medication class counts were defined as a total number of groups (DPP4, SGLT2, SU, .. ) where insulin was classified into 3 groups (rapid, mixed, and basal); the required prescription period was 3 months or more for each class. Statistical analysis was performed with R 3.6.0 on Ubuntu. For prediction, missing values were imputed by an R package {mice}. Results A total of 2,804 patients (M:F = 1375:1429, age 66.9+-13.6 (18--101, median 68) years) were analyzed whose median HbA1c was 6.14+-0.79 (3.6-11.6, median 5.95)%. This population was further divided into a proteinuric group (the median of dipstick proteinuria of 1+ or more, n=296) and a non-proteinuric group (the median of dipstick proteinuria of +- or less, n=2508). In the multivariate analysis, the proteinuric DM patients had the eGFR slope associated with initial eGFR, proteinuria, uric acid, and the number of classes of the anti-diabetic medications; higher uric acid and less number of DM medication were significantly associated with faster decline in eGFR. The non-proteinuric DM patients had eGFR slope associated with age, initial GFR, uric acid, chloride, and haemoglobin, but not with proteinuria; the patients with higher uric acid with lower haemoglobin had significantly faster decline in eGFR (-1.86 vs -1.34, P = 0.013). Prediction of faster eGFR decline was analyzed with machine learning technologies, ie, {ranger} and {randomForest}, where precision was 68.9%/67.9% (proteinuric group, ranger/randomForest) vs 76.8%/75.9% (non-proteinuric group, ranger/randomForest). Conclusion Propensity to lose kidney function is different in each diabetic patient, which should to be ideally predicted in individual basis.

Urinary angiotensinogen as a surrogate marker predicting the antiproteinuric effects of angiotensin receptor blockers in patients with overt proteinuria: a multicenter prospective study

Background: Although urinary angiotensinogen (AGT) and renin reflect intrarenal renin-angiotensin system activity and are enhanced in proteinuric chronic kidney disease, the clinical value of urinary AGT and renin levels during antiproteinuric treatment has yet to be determined. We investigated the clinical usefulness of initial urinary AGT or renin to determine the antiproteinuric effects of angiotensin receptor blockers (ARBs). Methods: This multicenter, prospective, single-arm study included 205 patients with overt proteinuria (urinary protein/creatinine ratio [uPCR] ≥ 1 mg/mg) enrolled between April 2009 and December 2011. All patients were treated with valsartan. The urinary AGT/creatinine ratio (uAGT/Cr) was measured at the baseline and 24 weeks, and the renin/creatinine ratio (uR/Cr) was measured at the baseline. Fifty-six patients were followed-up for 5 years. Results: The mean age was 47.6 years and 51.2% were male. The mean uPCR was 2.32 mg/mg and the mean eGFR was 63.2 mL/min/1.73m2. Natural logarithms (ln) (uAGT/Cr), ln(uR/Cr), and diabetes mellitus were associated with proteinuria decrement (decrease in uPCR ≥ 1 mg/mg). Ln(uAGT/Cr) was an independent predictor for proteinuria decrement (OR 1.372, 95% CI, 1.068–1.762, P = 0.013). Among the 56 patients followed-up for 5 years, Δln(uAGT/Cr) at 24 weeks was an independent predictor for uPCR < 1 mg/mg at 5 years (OR 0.379, 95% CI, 0.20–0.715, P = 0.003). Conclusions: Our study demonstrates the potential role of both baseline urinary AGT and changes in urinary AGT during the initial 24 weeks as surrogate markers predicting the antiproteinuric effects of ARBs in patients with overt proteinuria.

Urinary angiotensinogen as a surrogate marker predicting the antiproteinuric effects of angiotensin receptor blockers in patients with overt proteinuria: a multicenter prospective study

Background: Although urinary angiotensinogen (AGT) and renin reflect intrarenal renin-angiotensin system activity and are enhanced in proteinuric chronic kidney disease, the clinical value of urinary AGT and renin levels during antiproteinuric treatment has yet to be determined. We investigated the clinical usefulness of initial urinary AGT or renin to determine the antiproteinuric effects of angiotensin receptor blockers (ARBs). Methods: This multicenter, prospective, single-arm study included 205 patients with overt proteinuria (urinary protein/creatinine ratio [uPCR] ≥ 1 mg/mg) enrolled between April 2009 and December 2011. All patients were treated with valsartan. The urinary AGT/creatinine ratio (uAGT/Cr) was measured at the baseline and 24 weeks, and the renin/creatinine ratio (uR/Cr) was measured at the baseline. Fifty-six patients were followed-up for 5 years. Results: The mean age was 47.6 years and 51.2% were male. The mean uPCR was 2.32 mg/mg and the mean eGFR was 63.2 mL/min/1.73m2. Natural logarithms (ln) (uAGT/Cr), ln(uR/Cr), and diabetes mellitus were associated with proteinuria decrement (decrease in uPCR ≥ 1 mg/mg). Ln(uAGT/Cr) was an independent predictor for proteinuria decrement (OR 1.372, 95% CI, 1.068–1.762, P = 0.013). Among the 56 patients followed-up for 5 years, Δln(uAGT/Cr) at 24 weeks was an independent predictor for uPCR < 1 mg/mg at 5 years (OR 0.379, 95% CI, 0.20–0.715, P = 0.003). Conclusions: Our study demonstrates the potential role of both baseline urinary AGT and changes in urinary AGT during the initial 24 weeks as surrogate markers predicting the antiproteinuric effects of ARBs in patients with overt proteinuria.

Urinary angiotensinogen as a surrogate marker predicting the antiproteinuric effects of angiotensin receptor blockers in patients with overt proteinuria

Background: Although urinary angiotensinogen (AGT) and renin reflect intrarenal renin-angiotensin system activity and are enhanced in proteinuric chronic kidney disease, the clinical value of urinary AGT and renin levels during antiproteinuric treatment has yet to be determined. We investigated the clinical usefulness of initial urinary AGT or renin to determine the antiproteinuric effects of angiotensin receptor blockers (ARBs). Methods: This multicenter, prospective, single-arm study included 205 patients with overt proteinuria (urinary protein/creatinine ratio [uPCR] ≥ 1 mg/mg) enrolled between April 2009 and December 2011. All patients were treated with valsartan. The urinary AGT/creatinine ratio (uAGT/Cr) was measured at the baseline and 24 weeks, and the renin/creatinine ratio (uR/Cr) was measured at the baseline. Fifty-six patients were followed-up for 5 years. Results: The mean age was 47.6 years and 51.2% were male. The mean uPCR was 2.32 mg/mg and the mean eGFR was 63.2 mL/min/1.73m 2 . Natural logarithms (ln) (uAGT/Cr), ln(uR/Cr), and diabetes mellitus were associated with proteinuria decrement (decrease in uPCR ≥ 1 mg/mg). Ln(uAGT/Cr) was an independent predictor for proteinuria decrement (OR 1.372, 95% CI, 1.068–1.762, P = 0.013). Among the 56 patients followed-up for 5 years, Δln(uAGT/Cr) at 24 weeks was an independent predictor for uPCR < 1 mg/mg at 5 years (OR 0.379, 95% CI, 0.20–0.715, P = 0.003). Conclusions: Our study demonstrates the potential role of both baseline urinary AGT and changes in urinary AGT during the initial 24 weeks as surrogate markers predicting the antiproteinuric effects of ARBs in patients with overt proteinuria.