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Background/Objectives: Comprehensive conservative management (CCM) is a viable treatment option for elderly patients with end-stage kidney disease (ESKD). However, it involves a significant change in dietary habits, such as adopting a low-protein diet. Therefore, it is crucial to understand its impact on the patient's quality of life (QoL), particularly when compared to hemodialysis (HD). The study aims to evaluate the differences in the QoL between patients undergoing CCM and HD. Methods: The study included 50 patients over 75 with ESKD, with 25 patients in the CCM group and 25 in the HD group. The CCM group followed a personalized low-protein diet, while the HD group did not have protein restrictions. Various parameters were assessed, including demographic data, urine output, blood tests, comorbidity index, Visual Analog Scale (VAS), and hospitalization. The SF-12 questionnaire assessed the QoL, and the Physical Composite Score (PCS) and Mental Composite Score (MCS) were calculated. Results: The study revealed no age and comorbidity index differences between CCM and HD patients. In contrast, CCM patients reported significantly better physical and mental well-being than HD patients. In univariate analysis, CCM (B 0.24, p = 0.001), protein intake (B −0.004, p = 0.008), hospitalization (B −0.18, p = 0.024), urine output (B 0.25, p = 0.001), and VAS (B −0.26, p < 0.001) influenced the PCS. At the same time, only the type of treatment (B = 0.15, p = 0.048), urine output (B 0.18, p = 0.02), and VAS (B −0.14, p = 0.048) influence the MCS. In contrast, in multivariate analysis, only CCM contributed to an improved PCS (B 0.19, p = 0.003) and MCS (B 0.16, p = 0.03), while a higher VAS worsened the PCS (B −0.24, p < 0.001) and MCS (B −0.157, p = 0.0024). Conclusions: In elderly patients with similar basal conditions, health-related QoL perception is better in CCM than in HD patients. [ABSTRACT FROM AUTHOR]

Managing mineral bone disease (MBD) could reduce cardiovascular risk and improve the survival of dialysis patients. Our study focuses on the impact of calcium bath exposure in dialysis patients by comparing peritoneal dialysis patients (PD, intervention group) and hemodialysis patients (HD, control group). We assessed various factors, including calcium, phosphorus, magnesium, PTH, vitamin D 25-OH, C-terminal telopeptide (CTX), and FGF-23 levels, as well as the calcium bath six hours before the blood sample and the length of daily calcium exposure. We enrolled 40 PD and 31 HD patients with a mean age of 68.7 ± 13.6 years. Our cohort had median PTH and FGF-23 levels of 194 ng/L (Interquartile range [IQR] 130-316) and 1296 pg/mL (IQR 396-2698), respectively. We identified the length of exposure to a 1.25 mmol/L calcium bath, phosphate levels, and CTX as independent predictors of PTH (OR 0.279, p = 0.011; OR 0.277, p = 0.012; OR 0.11, p = 0.01, respectively). In contrast, independent predictors of FGF-23 were phosphate levels (OR 0.48, p < 0.001) and serum calcium levels (OR 0.25, p = 0.015), which were affected by the calcium bath. These findings suggest that managing dialysate calcium baths impacts phosphaturic hormones and could be a critical factor in optimizing CKD-MBD treatment in PD patients, sparking a new avenue of research and potential interventions. [ABSTRACT FROM AUTHOR]

Dent disease (DD1) is a rare tubulopathy caused by mutations in the CLCN5 gene. Glomerulosclerosis was recently reported in DD1 patients and ClC-5 protein was shown to be expressed in human podocytes. Nephrin and actin cytoskeleton play a key role for podocyte functions and podocyte endocytosis seems to be crucial for slit diaphragm regulation. The aim of this study was to analyze whether ClC-5 loss in podocytes might be a direct consequence of the glomerular damage in DD1 patients. Three DD1 kidney biopsies presenting focal global glomerulosclerosis and four control biopsies were analyzed by immunofluorescence (IF) for nephrin and podocalyxin, and by immunohistochemistry (IHC) for ClC-5. ClC-5 resulted as down-regulated in DD1 vs. control (CTRL) biopsies in both tubular and glomerular compartments (p < 0.01). A significant down-regulation of nephrin (p < 0.01) in DD1 vs. CTRL was demonstrated. CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats/Caspase9) gene editing of CLCN5 in conditionally immortalized human podocytes was used to obtain clones with the stop codon mutation p.(R34Efs*14). We showed that ClC-5 and nephrin expression, analyzed by quantitative Reverse Transcription/Polymerase Chain Reaction (qRT/PCR) and In-Cell Western (ICW), was significantly downregulated in mutant clones compared to the wild type ones. In addition, F-actin staining with fluorescent phalloidin revealed actin derangements. Our results indicate that ClC-5 loss might alter podocyte function either through cytoskeleton disorganization or through impairment of nephrin recycling. [ABSTRACT FROM AUTHOR]

Abstract Background Understanding how mesenchymal cells arise from epithelial cells could have a strong impact in unveiling mechanisms of epithelial cell plasticity underlying kidney regeneration and repair. In primary human tubular epithelial cells (HUTEC) under different TGFβ1 concentrations we had observed epithelial-to-mesenchymal transition (EMT) but not epithelial-myofibroblast transdifferentiation. We hypothesized that the process triggered by TGFβ1 could be a dedifferentiation event. The purpose of this study is to comprehensively delineate genetic programs associated with TGFβ1-driven EMT in our in vitro model using gene expression profile on large-scale oligonucleotide microarrays. Results In HUTEC under TGFβ1 stimulus, 977 genes were found differentially expressed. Thirty genes were identified whose expression depended directly on TGFβ1 concentration. By mapping the differentially expressed genes in the Human Interactome Map using Cytoscape software, we identified a single scale-free network consisting of 2630 interacting proteins and containing 449 differentially expressed proteins. We identified 27 hub proteins in the interactome with more than 29 edges incident on them and encoded by differentially expressed genes. The Gene Ontology analysis showed an excess of up-regulated proteins involved in biological processes, such as "morphogenesis", "cell fate determination" and "regulation of development", and the most up-regulated genes belonged to these categories. In addition, 267 genes were mapped to the KEGG pathways and 14 pathways with more than nine differentially expressed genes were identified. In our model, Smad signaling was not the TGFβ1 action effector; instead, the engagement of RAS/MAPK signaling pathway seems mainly to regulate genes involved in the cell cycle and proliferation/apoptosis. Conclusion Our present findings support the hypothesis that context-dependent EMT generated in our model by TGFβ1 might be the outcome of a dedifferentiation. In fact: 1) the principal biological categories involved in the process concern morphogenesis and development; 2) the most up-regulated genes belong to these categories; and, finally, 3) some intracellular pathways are involved, whose engagement during kidney development and nephrogenesis is well known. These long-term effects of TGFβ1 in HUTEC involve genes that are highly interconnected, thereby generating a scale-free network that we named the "TGFβ1 interactome", whose hubs represent proteins that may have a crucial role for HUTEC in response to TGFβ1.

Dent disease is a rare genetic proximal tubulopathy which is under-recognized. Its phenotypic heterogeneity has led to several different classifications of the same disorder, but it is now widely accepted that the triad of symptoms low-molecular-weight proteinuria, hypercalciuria and nephrocalcinosis/nephrolithiasis are pathognomonic of Dent disease. Although mutations on the CLCN5 and OCRL genes are known to cause Dent disease, no such mutations are found in about 25–35% of cases, making diagnosis more challenging. This review outlines current knowledge regarding Dent disease from another perspective. Starting from the history of Dent disease, and reviewing the clinical details of patients with and without a genetic characterization, we discuss the phenotypic and genetic heterogeneity that typifies this disease. We focus particularly on all those confounding clinical signs and symptoms that can lead to a misdiagnosis. We also try to shed light on a concealed aspect of Dent disease. Although it is a proximal tubulopathy, its misdiagnosis may lead to patients undergoing kidney biopsy. In fact, some individuals with Dent disease have high-grade proteinuria, with or without hematuria, as in the clinical setting of glomerulopathy, or chronic kidney disease of uncertain origin. Although glomerular damage is frequently documented in Dent disease patients' biopsies, there is currently no reliable evidence of renal biopsy being of either diagnostic or prognostic value. We review published histopathology reports of tubular and glomerular damage in these patients, and discuss current knowledge regarding the role of CLCN5 and OCRL genes in glomerular function. [ABSTRACT FROM AUTHOR]

ClC-5, the electrogenic chloride/proton exchanger strongly expressed in renal proximal tubules, belongs to the endocytic macromolecular complex responsible for albumin and low-molecular-weight protein uptake. ClC-5 was found to be overexpressed in glomeruli of glomerulonephritis and in cultured human podocytes under albumin overload. The transcriptional regulation of human ClC-5 is not fully understood. Three functional promoters of various strengths and 11 different 5' untranslated region (5'UTR) isoforms of CLCN5 messenger RNA (mRNA) were detected in the human kidney (variants 1-11). The aim of this study was to investigate the expression pattern of CLCN5 5'UTR variants and the CLCN5 common translated region in glomerulonephritis. The 5'UTR ends and the translated region of CLCN5 mRNA were analyzed using quantitative relative real-time PCR or quantitative comparative endpoint PCR with GAPDH as housekeeping gene in 8 normal kidneys and 12 renal biopsies from patients with glomerulonephritis. The expression profile for all variants in normal and glomerulonephritis biopsies was similar, and variant 3 and alternative variant 4 were the most abundantly expressed in both sets. In glomerulonephritis biopsies, isoforms under the control of a weak promoter (variants 4, 6 and 7) showed an increased expression leading to an increase in the CLCN5 translated region, underscoring their importance in kidney pathophysiology. Since weak promoters can be turned on by different stimuli, these data support the hypothesis that proteinuria could be one of the stimuli capable of starting a signaling pathway that induces an increase in CLCN5 transcription. [ABSTRACT FROM AUTHOR]

Dent disease (DD), an X-linked renal tubulopathy, is mainly caused by loss-of-function mutations in CLCN5 (DD1) and OCRL genes. CLCN5 encodes the ClC-5 antiporter that in proximal tubules (PT) participates in the receptor-mediated endocytosis of low molecular weight proteins. Few studies have analyzed the PT expression of ClC-5 and of megalin and cubilin receptors in DD1 kidney biopsies. About 25% of DD cases lack mutations in either CLCN5 or OCRL genes (DD3), and no other disease genes have been discovered so far. Sanger sequencing was used for CLCN5 gene analysis in 158 unrelated males clinically suspected of having DD. The tubular expression of ClC-5, megalin, and cubilin was assessed by immunolabeling in 10 DD1 kidney biopsies. Whole exome sequencing (WES) was performed in eight DD3 patients. Twenty-three novel CLCN5 mutations were identified. ClC-5, megalin, and cubilin were significantly lower in DD1 than in control biopsies. The tubular expression of ClC-5 when detected was irrespective of the type of mutation. In four DD3 patients, WES revealed 12 potentially pathogenic variants in three novel genes (SLC17A1, SLC9A3, and PDZK1), and in three genes known to be associated with monogenic forms of renal proximal tubulopathies (SLC3A, LRP2, and CUBN). The supposed third Dent disease-causing gene was not discovered. [ABSTRACT FROM AUTHOR]

Nephrocalcinosis involves the deposition of microscopic crystals in the tubular lumen or interstitium. While the clinical, biochemical, and genetic aspects of the diseases causing nephrocalcinosis have been elucidated, little is known about the cellular events in this calcification process.We previously reported a phenomenon involving the spontaneous formation of Ca2PO4 nodules in primary papillary renal cells from a patient with medullary nephrocalcinosis harboring a rare glial cell-derived neurotrophic factor (GDNF) gene variant. We also demonstrated that cultivating GDNF-silenced human kidney-2 (HK-2) cells in osteogenic conditions for 15 days triggered Ca2PO4 deposits. Given the reportedly close relationship between cell death and pathological calcification, aim of the present study was to investigate whether apoptosis is involved in the calcification of GDNF-silenced HK-2 cells under osteogenic conditions. Silenced and control cells were cultured in standard and osteogenic medium for 1, 5, and 15 days, and any Ca2PO4 deposition was identified by means of von Kossa staining and environmental SEM (ESEM) analyses. Based on the results of annexin V and propidium iodide (PI) analysis, and terminal deoxynucleotidyl transferase dUTP-biotin nick end labeling (TUNEL) assay, the silenced cells in the osteogenic medium showed a significant increase in the percentage of cells in the late phase of apoptosis and an increased Ca2PO4 deposition at 15 days. The results of quantitative real-time PCR (qRT-PCR) of BAX and BCL2, and in-cell Western analysis of caspases indicated that the cell death process was independent of caspase-3, -6, -7, and -9 activation, however. Using this model, we provide evidence of caspase-independent cell death triggering the calcification process in GDNF-silenced HK-2 cells. [ABSTRACT FROM AUTHOR]

The need of renal biopsy in patients with CKD of unknown origin, even without significant proteinuria, becomes therefore crucial for LCCD diagnosis. Light Chain Deposition Disease (LCDD) with low proteinuria is rare and represents a diagnostic challenge. [Extracted from the article]

Dent's disease is an X-linked renal tubulopathy caused by mutations mainly affecting the CLCN5 gene. Defects in the OCRL gene, which is usually mutated in patients with Lowe syndrome, have been shown to lead to a Dent-like phenotype called Dent disease 2. However, about 20% of patients with Dent's disease carry no CLCN5/OCRL mutations. The disease's genetic heterogeneity is accompanied by interfamilial and intrafamilial phenotypic heterogeneity. We report on a case of Dent's disease with a very unusual phenotype (dysmorphic features, ocular abnormalities, growth delay, rickets, mild mental retardation) in which a digenic inheritance was discovered. Two different, novel disease-causing mutations were detected, both inherited from the patient's healthy mother, that is a truncating mutation in the CLCN5 gene (A249fs*20) and a donor splice-site alteration in the OCRL gene (c.388+3A>G). The mRNA analysis of the patient's leukocytes revealed an aberrantly spliced OCRL mRNA caused by in-frame exon 6 skipping, leading to a shorter protein, but keeping intact the central inositol 5-phosphatase domain and the C-terminal side of the ASH-RhoGAP domain. Only wild-type mRNA was observed in the mother's leukocytes due to a completely skewed X inactivation. Our results are the first to reveal the effect of an epistatic second modifier in Dent's disease too, which can modulate its expressivity. We surmise that the severe Dent disease 2 phenotype of our patient might be due to an addictive interaction of the mutations at two different genes. [ABSTRACT FROM AUTHOR]

Dent disease is a rare X-linked renal tubulopathy due to CLCN5 and OCRL (DD2) mutations. OCRL mutations also cause Lowe syndrome (LS) involving the eyes, brain and kidney. DD2 is frequently described as a mild form of LS because some patients may present with extra-renal symptoms (ESs). Since DD2 is a rare disease and there are a low number of reported cases, it is still unclear whether it has a clinical picture distinct from LS. We retrospectively analyzed the phenotype and genotype of our cohort of 35 DD2 males and reviewed all published DD2 cases. We analyzed the distribution of mutations along the OCRL gene and evaluated the type and frequency of ES according to the type of mutation and localization in OCRL protein domains. The frequency of patients with at least one ES was 39%. Muscle findings are the most common ES (52%), while ocular findings are less common (11%). Analysis of the distribution of mutations revealed (1) truncating mutations map in the PH and linker domain, while missense mutations map in the 5-phosphatase domain, and only occasionally in the ASH-RhoGAP module; (2) five OCRL mutations cause both DD2 and LS phenotypes; (3) codon 318 is a DD2 mutational hot spot; (4) a correlation was found between the presence of ES and the position of the mutations along OCRL domains. DD2 is distinct from LS. The mutation site and the mutation type largely determine the DD2 phenotype. [ABSTRACT FROM AUTHOR]

Apoptotic cell death is usually a response to the cell's microenvironment. In the kidney, apoptosis contributes to parenchymal cell loss in the course of acute and chronic renal injury, but does not trigger an inflammatory response. What distinguishes necrosis from apoptosis is the rupture of the plasma membrane, so necrotic cell death is accompanied by the release of unprocessed intracellular content, including cellular organelles, which are highly immunogenic proteins. The relative contribution of apoptosis and necrosis to injury varies, depending on the severity of the insult. Regulated cell death may result from immunologically silent apoptosis or from immunogenic necrosis. Recent advances have enhanced the most revolutionary concept of regulated necrosis. Several modalities of regulated necrosis have been described, such as necroptosis, ferroptosis, pyroptosis, and mitochondrial permeability transition-dependent regulated necrosis. We review the different modalities of apoptosis, necrosis, and regulated necrosis in kidney injury, focusing particularly on evidence implicating cell death in ectopic renal calcification. We also review the evidence for the role of cell death in kidney injury, which may pave the way for new therapeutic opportunities. [ABSTRACT FROM AUTHOR]

Background Anti-pentraxin 3 (PTX3) antibodies were associated with the absence of lupus glomerulonephritis in humans. Aim To explore the effects of anti-PTX3 antibodies in New Zealand Black/White (NZB/NZW F1) mice and their inherent mechanisms of action. Materials and methods 30 NZB/NZW F1 mice were subdivided into 3 groups of 10 mice each and subcutaneously injected with PTX3, alum and PBS (group 1), alum and PBS (group 2) or PBS alone (group 3), 3 times 3 weeks apart, before development of renal disease. Mice were followed until natural death. Histological analysis and immunohistochemistry were performed on harvested kidneys. Effects of anti-PTX3 antibodies on C1q binding to immobilized PTX3-anti-PTX3 immune complexes were evaluated in vitro using human SLE sera. Qualitative characterization of human IgG anti-PTX3 was performed. Results Only group 1 mice developed anti-PTX3 antibodies. Anti-dsDNA and anti-C1q antibodies appeared significantly later and at lower levels in group 1 mice vs. controls (p < 0.0001). Proteinuria-free and overall survival were significantly increased in group 1 mice vs. controls (p < 0.05 and p = 0.03, respectively). Histopathological analysis showed that glomerular and tubular PTX3 staining and renal lesions were increased in controls compared with immunized mice. Addition of human SLE sera positive for anti-PTX3 antibodies to C1q and fixed PTX3 interfered with C1q binding to PTX3-anti-PTX3 immune complexes. Qualitative characterization of human IgG anti-PTX3 showed an increased proportion of IgG4. Conclusions Anti-PTX3 antibodies delay lupus-like nephritis and prolong survival of NZB/NZW F1 mice. In vitro observations suggest anti-PTX3 antibodies may dampen complement activation via their Fc fragment, likely hindering renal inflammation. [ABSTRACT FROM AUTHOR]