Background Diabetic nephropathy (DN) is the most common cause of end-stage renal disease, affecting ∼30% of the rapidly growing diabetic population, and strongly associated with cardiovascular risk. Despite this, the molecular mechanisms of disease remain unknown. Methods RNA sequencing (RNAseq) was performed on paired, micro-dissected glomerular and tubulointerstitial tissue from patients diagnosed with DN [n = 19, 15 males, median (range) age: 61 (30–85) years, chronic kidney disease stages 1–4] and living kidney donors [n = 20, 12 males, median (range) age: 56 (30–70) years]. Results Principal component analysis showed a clear separation between glomeruli and tubulointerstitium transcriptomes. Differential expression analysis identified 1550 and 4530 differentially expressed genes, respectively (adjusted P < 0.01). Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses highlighted activation of inflammation and extracellular matrix (ECM) organization pathways in glomeruli, and immune and apoptosis pathways in tubulointerstitium of DN patients. Specific gene modules were associated with renal function in weighted gene co-expression network analysis. Increased messengerRNA (mRNA) expression of renal damage markers lipocalin 2 (LCN) and hepatitis A virus cellular receptor1 (HAVCR1) in the tubulointerstitial fraction was observed alongside higher urinary concentrations of the corresponding proteins neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) in DN patients. Conclusions Here we present the first RNAseq experiment performed on paired glomerular and tubulointerstitial samples from DN patients. We show that prominent disease-specific changes occur in both compartments, including relevant cellular processes such as reorganization of ECM and inflammation (glomeruli) as well as apoptosis (tubulointerstitium). The results emphasize the potential of utilizing high-throughput transcriptomics to decipher disease pathways and treatment targets in this high-risk patient population.

Renal glomeruli are the primary target of injury in diabetic nephropathy (DN), and the glomerular podocyte has a key role in disease progression. To identify potential novel therapeutic targets for DN, we performed high-throughput molecular profiling of G protein-coupled receptors (GPCRs) using human glomeruli. We identified an orphan GPCR, Gprc5a, as a highly podocyte-specific gene, the expression of which was significantly downregulated in glomeruli of patients with DN compared with those without DN. Inactivation of Gprc5a in mice resulted in thickening of the glomerular basement membrane and activation of mesangial cells, which are two hallmark features of DN in humans. Compared with wild-type mice, Gprc5a-deficient animals demonstrated increased albuminuria and more severe histologic changes after induction of diabetes with streptozotocin. Mechanistically, Gprc5a modulated TGF- signaling and activation of the EGF receptor in cultured podocytes. Gprc5a has an important role in the pathogenesis of DN, and further study of the podocyte-specific signaling activity of this protein is warranted.

Aim To study tactics of outpatient physicians in choosing the treatment when the previous double antihypertensive therapy (AHT) fails and to analyze the effectivity of an amlodipine/indapamide/perindopril arginine triple combination (TC).Material and methods The program included 1252 patients with arterial hypertension (AH); the TC group consisted of 992 (79.23 %) patients (38.3 % males; age, 61.6 [55.0; 67.9]); the control group included 260 (20.77 %) patients (37.7 % males; age, 60.6 [53.3; 67.4]). The main inclusion criteria were essential AH, age 18-79 years, insufficient response to previous AHT (clinical systolic blood pressure (SBP) >140–179 mm Hg). The study duration was three months. The following parameters were evaluated: dynamics of clinical and ambulatory BP (BP self-monitoring (BPSM); frequency of achieving the first goal of <140 / 90 mm Hg and the goal of <130 / 80 mm Hg); and changes in glomerular filtration rate (GFR) and quality of life (QoL). Responses to TC were analyzed in groups with different ranges of increased baseline SBP in patients with AH and diabetes mellitus (DM)/impaired glucose tolerance (IGT), overweight or obesity, and chronic kidney disease (CKD, reduced estimated GFR (eGFR <60 ml/min/1.73 m2). Safety was evaluated based on records of adverse events (AEs).Results The TC group had a more severe condition at baseline by clinical parameters and history and had higher baseline BP, which made difficult the intergroup comparison. Nevertheless at three months, the decrease in clinical SBP was more pronounced in the TC group (from 162.1  to 126.8 mm Hg, Δ=35.7  mm Hg) than in the control group (from 157.8 to 128.4  mm Hg, Δ=29.4  mm Hg). 87.8% of patients in the TC group and 81.9 % (р=0.012) in the control group achieved the first BP goal of <140 / 90 mm Hg; 34.3% and 28.2% of patients, respectively, achieved the BP goal of <130 / 80 mm Hg (р=0.055). The more effective SBP control in the TC group was associated with a pronounced BP decrease with higher BP values at baseline, which was also confirmed by an analysis in subgroups with SBP 140–160, 160–180, and >180 mm Hg. The TC treatment was associated with a pronounced antihypertensive effect with respect of BPSM values, improved QoL, and renal function. Significant decreases in BP and achievement of BP goals by a vast majority of patients receiving TC were also observed in subgroups with DM or IGT, overweight and/or obesity, and CKD. AEs were observed during the treatment only in 8 patients (0.64 %), which confirmed good tolerability and high safety of the therapy.Conclusion The study results demonstrated a therapeutic effect of the amlodipine/indapamide/perindopril arginine fixed-dose combination (Triplixam®). This effect was evident as control of clinical BP with any baseline BP level, including different ranges of increased SBP, in AH combined with DM, IGT, obesity, and CKD, which offers advantages over a subjective choice of AHT. TC improved BPSM values, QoL indexes, provided nephroprotection, and was well tolerated.

Background: Inflammation and oxidative stress play important roles in the pathogenesis and progression of chronic kidney disease (CKD) and in its complications, in particular cardiovascular disease, a major cause of death among patients undergoing dialysis treatment. We recently described that Glutaredoxin1 (Grx), an intracellular antioxidant, catalyzes oxidoreductase reactions also extracellularly, and that serum Grx levels correlate to disease severity in type 2 diabetes. Aim: In the current study we assess Grx as a potential clinical marker of oxidative stress in CKD. Methods: We examined Grx activity in 25 patients with different stages of chronic kidney failure, 19 control subjects, and 36 patients at initiation of dialysis and after 2 years of dialysis. Results: We found that Grx activity was significantly higher in CKD patients compared to control subjects, indicating an oxidized extracellular environment in CKD. Grx levels correlated to interleukin-6 and pentosidine, but not to age or GFR. In dialysis patients with Grx sampling before dialysis start and after 2 years of dialysis, Grx levels increased more in hemodialysis (HD) patients than in peritoneal dialysis patients, indicating an increased oxidative stress imbalance in HD patients. Patients who experienced a stroke or myocardial infarction at any time had a significantly higher increase in Grx during the 2 years of dialysis, compared to patients without stroke or myocardial infarction, indicating a possible association between high Grx levels and a cardiovascular event. Conclusion: Our pilot study indicates that Grx may be a useful marker for assessing the degree of oxidative stress in CKD, however this needs further investigation in a larger prospective patient cohort.

Background Immunoglobulin A nephropathy (IgAN) and its systemic variant IgA vasculitis (IgAV) damage the glomeruli, resulting in proteinuria, hematuria and kidney impairment. Dendrin is a podocyte-specific protein suggested to be involved in the pathogenesis of IgAN. Upon cell injury, dendrin translocates from the slit diaphragm to the nucleus, where it is suggested to induce apoptosis and cytoskeletal changes, resulting in proteinuria and accelerated disease progression in mice. Here we investigated gene and protein expression of dendrin in relation to clinical and histopathological findings to further elucidate its role in IgAN/IgAV. Methods Glomerular gene expression was measured using microarray on 30 IgAN/IgAV patients, 5 patients with membranous nephropathy (MN) and 20 deceased kidney donors. Dendrin was spatially evaluated on kidney tissue sections by immunofluorescence (IF) staining (IgAN patients, n = 4; nephrectomized kidneys, n = 3) and semi-quantified by immunogold electron microscopy (IgAN/IgAV patients, n = 21; MN, n = 5; living kidney donors, n = 6). Histopathological grading was performed according to the Oxford and Banff classifications. Clinical data were collected at the time of biopsy and follow-up. Results Dendrin mRNA levels were higher (P = .01) in IgAN patients compared with MN patients and controls and most prominently in patients with preserved kidney function and fewer chronic histopathological changes. Whereas IF staining did not differ between groups, immunoelectron microscopy revealed that a higher relative nuclear dendrin concentration in IgAN patients was associated with a slower annual progression rate and milder histopathological changes. Conclusion Dendrin messenger RNA levels and relative nuclear protein concentrations are increased and associated with a more benign phenotype and progression in IgAN/IgAV patients.

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BACKGROUND AND AIMS As the most common glomerulonephritis globally, mainly affecting younger adults and one of the most common causes of kidney failure [1], IgA Nephropathy (IgAN) poses an immense impact both on the individual and on the societal level. Here, we aimed to gain further molecular insight into the high interindividual variability of the clinical picture and disease progression by linking transcriptional profiling of IgAN-kidneys to clinical and histopathological data. METHOD Kidney biopsies from patients with histopathologically verified IgAN/IgA vasculitis (n = 84) (IgAV) [57 males, median (range) age of 39 (4–89) years] and 11 living donors (LD) [six males, median (range) age of 37 (30–65) years] were manually microdissected into glomerular and tubulointerstitial fractions. RNA was extracted with RNeasy lipid tissue mini kit (Qiagen, Valencia, CA, US) and evaluated using the Bioanalyzer 2100 (Agilent, Santa Clara, CA, US). mRNA purification, conversion to cDNA, fragmentation and double-stranded cDNA synthesis, amplification and clean-up were performed using Illumina Stranded mRNA prep ligation protocol (Illumina Inc). Paired-end RNA sequencing was performed in three different batches (Illumina Novaseq 6000). Data pre-processing was done using Trim Galore (v.0.6.4). Reads were aligned to the Ensembl GRCh38 reference genome using STAR (v2.6.1d). Gene counts were obtained using featureCounts (v1.5.1). Quality control was made using MultiQC (v.1.7). Comparisons between groups were performed using Bioconductor package DESeq2 (v1.22.2) and gene set enrichment analysis using Bioconductor package fgsea. The biopsies were evaluated by experienced renal pathologists using the Oxford classification [2] and the Banff classifications [3]. Clinical data at time of biopsy and 5-year follow-up was retrieved from patients’ files. Co-morbidity- and mortality data was extracted from the Swedish renal registry up to 19 years after the biopsy. RESULTS Principal Component Analysis showed clear separation between diseased and LD kidney transcriptomes, as well as between glomerular and tubulointerstitial fractions. Top upregulated genes in glomeruli were associated with complement activation and fibrosis. In tubulointerstium, top genes were related to the immune system, including chemokines. Gene ontology enrichment analysis highlighted immune response and complement activation in both compartments. Additionally, cell membrane and mitochondrial activity were enriched in tubulointerstium. Linking bioinformatic results to clinical data at the time of biopsy, progress over time as well as to histopathological data in accordance with the Oxford classification system [2] is ongoing. CONCLUSION This is, to our knowledge, the most comprehensive RNA sequencing performed on paired glomerular and tubulointerstitial tissue from patients with IgAN/IgAV. Initial bioinformatical analyses highlights biologically relevant processes involving different parts of the immune system. Our project has the potential to identify molecular processes associated with rapid disease progression and specific histopathological characteristics. This enables identification of patients with a more aggressive disease and individualized treatment depending on molecular profile, which would improve kidney survival and quality of life for patients suffering from IgAN/IgAV.