The rate of renal disease progression varies widely among patients with autosomal dominant polycystic kidney disease (ADPKD), necessitating optimal patient selection for enrollment into clinical trials. Patients from the Mayo Clinic Translational PKD Center with ADPKD (n=590) with computed tomography/magnetic resonance images and three or more eGFR measurements over $6 months were classified radiologically as typical (n=538) or atypical (n=52). Total kidney volume (TKV) was measured using stereology (TKVs) and ellipsoid equation (TKVe). Typical patients were randomly partitioned into development and internal validation sets and subclassified according to height-adjusted TKV (HtTKV) ranges for age (1A-1E, in increasing order). Consortium for Radiologic Imaging Study of PKD (CRISP) participants (n=173) were used for external validation. TKVe correlated strongly with TKVs, without systematic underestimation or overestimation. A longitudinal mixed regression model to predict eGFR decline showed that log 2 HtTKV and age significantly interacted with time in typical patients, but not in atypical patients. When 1A-1E classifications were used instead of log 2 HtTKV, eGFR slopes were significantly different among subclasses and, except for 1A, different from those in healthy kidney donors. The equation derived from the development set predicted eGFR in both validation sets. The frequency of ESRD at 10 years increased from subclass 1A (2.4%) to 1E (66.9%) in the Mayo cohort and from 1C (2.2%) to 1E (22.3%) in the younger CRISP cohort. Class and subclass designations were stable. An easily applied classification of ADPKD based on HtTKV and age should optimize patient selection for enrollment into clinical trials and for treatment when one becomes available.

Background and objectives: It was postulated that in patients with membranous nephropathy (MN), four weekly doses of Rituximab (RTX) would result in more effective B cell depletion, a higher remission rate, and maintaining the same safety profile compared with patients treated with RTX dosed at 1 g every 2 weeks. This hypothesis was supported by previous pharmacokinetic (PK) analysis showing that RTX levels in the two-dose regimen were 50% lower compared with nonproteinuric patients, which could potentially result in undertreatment.Design Conclusions: Four doses of RTX resulted in more effective B cell depletion, but proteinuria reduction was similar to RTX at 1 g every 2 weeks. Baseline quantification of lymphocyte subpopulations did not predict response to RTX therapy.

Autosomal dominant polycystic kidney disease (ADPKD) often results in ESRD but with a highly variable course. Mutations to PKD1 or PKD2 cause ADPKD; both loci have high levels of allelic heterogeneity. We evaluated genotype-phenotype correlations in 1119 patients (945 families) from the HALT Progression of PKD Study and the Consortium of Radiologic Imaging Study of PKD Study. The population was defined as: 77.7% PKD1, 14.7% PKD2, and 7.6% with no mutation detected (NMD). Phenotypic end points were sex, eGFR, height-adjusted total kidney volume (htTKV), and liver cyst volume. Analysis of the eGFR and htTKV measures showed that the PKD1 group had more severe disease than the PKD2 group, whereas the NMD group had a PKD2-like phenotype. In both the PKD1 and PKD2 populations, men had more severe renal disease, but women had larger liver cyst volumes. Compared with nontruncating PKD1 mutations, truncating PKD1 mutations associated with lower eGFR, but the mutation groups were not differentiated by htTKV. PKD1 nontruncating mutations were evaluated for conservation and chemical change and subdivided into strong (mutation strength group 2 [MSG2]) and weak (MSG3) mutation groups. Analysis of eGFR and htTKV measures showed that patients with MSG3 but not MSG2 mutations had significantly milder disease than patients with truncating cases (MSG1), an association especially evident in extreme decile populations. Overall, we have quantified the contribution of genic and PKD1 allelic effects and sex to the ADPKD phenotype. Intrafamilial correlation analysis showed that other factors shared by families influence htTKV, with these additional genetic/environmental factors significantly affecting the ADPKD phenotype.

Chronic kidney disease (CKD) remains a worldwide public health problem associated with serious complications and increased mortality rates. Accumulating evidence indicates that elevated intracellular levels of reactive oxygen species (ROS) play a major role in the pathogenesis of CKD. Increased intracellular levels of ROS can lead to oxidation of lipids, DNA, and proteins, contributing to cellular damage. On the other hand, ROS are also important secondary messengers in cellular signaling. Consequently, normal kidney cell function relies on the “right” amount of ROS. Mitochondria and NADPH oxidases represent major sources of ROS in the kidney, but renal antioxidant systems, such as superoxide dismutase, catalase, or glutathione peroxidase counterbalance ROS-mediated injury. This review discusses the main sources of ROS and antioxidant systems in the kidney, and redox signaling pathways leading to inflammation and fibrosis, which result in abnormal kidney function and CKD progression. We further discuss the important role of the nuclear factor erythroid 2-related factor 2 (Nrf2) in regulating antioxidant responses, and other mechanisms of redox signaling.

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SummaryBackground and objectives Autosomal dominant polycystic kidney disease (ADPKD) patients have an increased risk for intracranial aneurysms (IAs). The importance of screening for unruptured IAs (UIAs) depends on their risks for growth and rupture.Design, setting, participants, & measurements ADPKD patients with UIAs found by presymptomatic screening with magnetic resonance angiography (MRA) during 1989 to 2009 were followed initially at 6 months and annually, and less frequently after demonstration of stability.Results Forty-five saccular aneurysms were detected in 38 patients from 36 families. Most were small (median diameter 3.5 mm) and in the anterior circulation (84%). Median age at diagnosis was 49 years. During cumulative imaging follow-up of 243 years, one de novo UIA was detected and increased in size from 2 to 4.4 mm over 144 months and two UIAs grew from 4.5 to 5.9 mm and 4.7 to 6.2 mm after 69 and 184 months, respectively. Seven patients did not have imaging follow-up. No change was detected in the remaining 28 patients. During cumulative clinical follow-up of 316 years, no aneurysm ruptured. Five patients died from unrelated causes and two were lost to follow-up after 8 and 120 months. Three patients underwent surgical clipping. ConclusionsMost UIAs detected by presymptomatic screening in ADPKD patients are small and in the anterior circulation. Growth and rupture risks are not higher than those of UIAs in the general population. These data support very selective screening for UIAs in ADPKD patients, and widespread screening is not indicated.

Autosomal dominant polycystic kidney disease (ADPKD) is a common cause of ESRD. Affected individuals inherit a defective copy of either PKD1 or PKD2, which encode polycystin-1 (PC1) or polycystin-2 (PC2), respectively. PC1 and PC2 are secreted on urinary exosome-like vesicles (ELVs) (100-nm diameter vesicles), in which PC1 is present in a cleaved form and may be complexed with PC2. Here, label-free quantitative proteomic studies of urine ELVs in an initial discovery cohort (13 individuals with PKD1 mutations and 18 normal controls) revealed that of 2008 ELV proteins, 9 (0.32%) were expressed at significantly different levels in samples from individuals with PKD1 mutations compared to controls (P,0.03). In samples from individuals with PKD1 mutations, levels of PC1 and PC2 were reduced to 54% (P,0.02) and 53% (P,0.001), respectively. Transmembrane protein 2 (TMEM2), a protein with homology to fibrocystin, was 2.1-fold higher in individuals with PKD1 mutations (P,0.03). The PC1/TMEM2 ratio correlated inversely with height-adjusted total kidney volume in the discovery cohort, and the ratio of PC1/TMEM2 or PC2/TMEM2 could be used to distinguish individuals with PKD1 mutations from controls in a confirmation cohort. In summary, results of this study suggest that a test measuring the urine exosomal PC1/TMEM2 or PC2/TMEM2 ratio may have utility in diagnosis and monitoring of polycystic kidney disease. Future studies will focus on increasing sample size and confirming these studies. The data were deposited in the ProteomeXchange (identifier PXD001075).

Over 2 years, OctLAR significantly reduced the rate of increase in TLV and possibly the rate of increase in TKV.