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World Journal of Surgical Oncology Jan 2021Multiple myeloma causes different types of renal injury. C3 glomerulonephritis (C3GN) is characterised by an abnormal deposition of complement C3 in the glomeruli due to...
BACKGROUND
Multiple myeloma causes different types of renal injury. C3 glomerulonephritis (C3GN) is characterised by an abnormal deposition of complement C3 in the glomeruli due to abnormal activation of the alternative pathway of the complement system. While the association between C3GN and multiple myeloma has been well established, mild renal injury by C3GN in multiple myeloma patients with high levels of light chain has not been reported.
CASE PRESENTATION
A 55-year-old Chinese man presented with proteinuria. Combined with immunofixation electrophoresis, bone marrow biopsy, and renal biopsy, he was diagnosed with IgA-type multiple myeloma accompanied by C3GN and light chain proximal tubulopathy without crystal deposits. Although he had a higher level of lambda serum-free light chain, the renal injury in this patient was mild. After treatment with four courses of BD, one course of PAD, and autologous stem cell transplantation, he achieved a very good partial hematologic response with stable renal function.
CONCLUSIONS
In multiple myeloma, the light chain reaches a certain level and persists, resulting in C3GN renal impairment. Early diagnosis and early intensive treatment are critical for the prognosis of such patients.
Topics: Glomerulonephritis; Hematopoietic Stem Cell Transplantation; Humans; Male; Middle Aged; Multiple Myeloma; Prognosis; Transplantation, Autologous
PubMed: 33482806
DOI: 10.1186/s12957-021-02135-3 -
World Journal of Hepatology Dec 2020The recommended monitoring tools for evaluating nucleot(s)ide analogue renal toxicity, such as estimated glomerular filtration rate (eGFR) and phosphatemia, are late...
BACKGROUND
The recommended monitoring tools for evaluating nucleot(s)ide analogue renal toxicity, such as estimated glomerular filtration rate (eGFR) and phosphatemia, are late markers of proximal tubulopathy. Multiple early markers are available, but no consensus exists on their use.
AIM
To determine the 24 mo prevalence of subclinical proximal tubulopathy (SPT), as defined with early biomarkers, in treated untreated hepatitis B virus (HBV)-monoinfected patients.
METHODS
A prospective, non-randomized, multicenter study of HBV-monoinfected patients with a low number of renal comorbidities was conducted. The patients were separated into three groups: Naïve, starting entecavir (ETV) treatment, or starting tenofovir disoproxil (TDF) treatment. Data on the early markers of SPT, the eGFR and phosphatemia, were collected quarterly. SPT was defined as a maximal tubular reabsorption of phosphate/eGFR below 0.8 mmoL/L and/or uric acid fractional excretion above 10%. The prevalence and cumulative incidence of SPT at month 24 (M24) were calculated. Quantitative data were analyzed using analyses of variance or Kruskal-Wallis tests, whereas chi-squared or Fisher's exact tests were used to analyze qualitative data. Multivariate analyses were used to adjust for any potential confounding factors.
RESULTS
Of the 196 patients analyzed, 138 (84 naïve, 28 starting ETV, and 26 starting TDF) had no SPT at inclusion. At M24, the prevalence of SPT was not statistically different between naïve and either treated group (21.1% 30.7%, 0.42 and 50.0% 30.7%, = 0.32 for ETV and TDF, respectively); no patient had an eGFR lower than 50 mL/min/1.73 m² or phosphatemia less than 0.48 mmoL/L. In the multivariate analysis, no explanatory variables were identified after adjustment. The cumulative incidence of SPT over 24 mo (25.5%, 13.3%, and 52.9% in the naïve, ETV, and TDF groups, respectively) tended to be higher in the TDF group the naïve group (hazard ratio: 2.283, = 0.05). SPT-free survival at M24 was 57.6%, 68.8%, and 23.5% for the naïve, ETV, and TDF groups, respectively. The median survival time without SPT, evaluated only in the TDF group, was 5.9 mo.
CONCLUSION
The prevalence and incidence of SPT was higher in TDF-treated patients compared to naïve patients. SPT in the naïve population suggests that HBV can induce renal tubular toxicity.
PubMed: 33442458
DOI: 10.4254/wjh.v12.i12.1326 -
American Journal of Physiology. Renal... Feb 2021The various forms of Fanconi renotubular syndromes (FRTS) offer significant challenges for clinicians and present unique opportunities for scientists who study proximal... (Review)
Review
The various forms of Fanconi renotubular syndromes (FRTS) offer significant challenges for clinicians and present unique opportunities for scientists who study proximal tubule physiology. This review will describe the clinical characteristics, genetic underpinnings, and underlying pathophysiology of the major forms of FRST. Although the classic forms of FRTS will be presented (e.g., Dent disease or Lowe syndrome), particular attention will be paid to five of the most recently discovered FRTS subtypes caused by mutations in the genes encoding for L-arginine:glycine amidinotransferase (), solute carrier family 34 (type Ii sodium/phosphate cotransporter), member 1 (), enoyl-CoAhydratase/3-hydroxyacyl CoA dehydrogenase (), hepatocyte nuclear factor 4A (), or NADH dehydrogenase complex I, assembly factor 6 (). We will explore how mutations in these genes revealed unexpected mechanisms that led to compromised proximal tubule functions. We will also describe the inherent challenges associated with gene discovery studies based on findings derived from small, single-family studies by focusing the story of FRTS type 2 (). Finally, we will explain how extensive alternative splicing of HNF4A has resulted in confusion with mutation nomenclature for FRTS type 4.
Topics: Fanconi Syndrome; Gene Expression Regulation; Genetic Predisposition to Disease; Humans; Kidney Tubules, Proximal; Mutation
PubMed: 33283647
DOI: 10.1152/ajprenal.00214.2020 -
PloS One 2020Chronic subclinical hemolysis is frequent in patients implanted with Left Ventricular Assist Device (LVAD) and is associated with adverse outcomes. Consequences of...
BACKGROUND
Chronic subclinical hemolysis is frequent in patients implanted with Left Ventricular Assist Device (LVAD) and is associated with adverse outcomes. Consequences of LVADs-induced subclinical hemolysis on kidney structure and function is currently unknown.
METHODS
Thirty-three patients implanted with a Heartmate II LVAD (Abbott, Inc, Chicago IL) were retrospectively studied. Hemolysis, Acute Kidney Injury (AKI) and the evolution of estimated Glomerular Filtration Rate were analyzed. Proximal Tubulopathy (PT) groups were defined according to proteinuria, normoglycemic glycosuria, and electrolytic disorders. The Receiver Operating Characteristic (ROC) curve was used to analyze threshold of LDH values associated with PT.
RESULTS
Median LDH between PT groups were statistically different, 688 IU/L [642-703] and 356 IU/L [320-494] in the "PT" and "no PT" groups, respectively p = 0.006. To determine PT group, LDH threshold > 600 IU/L was associated with a sensitivity of 85.7% (95% CI, 42.1-99.6) and a specificity of 84.6% (95% CI, 65.1-95.6). The ROC's Area Under Curve was 0.83 (95% CI, 0.68-0.98). In the "PT" group, patients had 4.2 [2.5-5.0] AKI episodes per year of exposure, versus 1.6 [0.4-3.7] in the "no PT" group, p = 0.03. A higher occurrence of AKI was associated with subsequent development of Chronic Kidney Disease (CKD) (p = 0.02) and death (p = 0.05).
CONCLUSIONS
LVADs-induced subclinical hemolysis is associated with proximal tubular functional alterations, which in turn contribute to the occurrence of AKI and subsequent CKD. Owing to renal toxicity of hemolysis, measures to reduce subclinical hemolysis intensity as canula position or pump parameters should be systematically considered, as well as specific nephroprotective therapies.
Topics: Acute Kidney Injury; Aged; Fanconi Syndrome; Female; Heart Failure; Heart-Assist Devices; Hematologic Tests; Hemolysis; Humans; Kidney; Kidney Tubules, Proximal; L-Lactate Dehydrogenase; Male; Middle Aged; Ventricular Dysfunction, Left
PubMed: 33253314
DOI: 10.1371/journal.pone.0242931 -
Clinical Nephrology. Case Studies 2020Dent disease is an inherited proximal renal tubulopathy leading to low molecular weight proteinuria, hypercalciuria with nephrocalcinosis and nephrolithiasis, and...
Dent disease is an inherited proximal renal tubulopathy leading to low molecular weight proteinuria, hypercalciuria with nephrocalcinosis and nephrolithiasis, and progressive renal failure. Two genetic mutations have been identified. The disease usually presents in childhood or early adult life and may be associated with other proximal tubular defects, which can lead to significant morbidity, especially in children. The disorder can extend to interstitial and glomerular cells, which contributes to progression to end-stage kidney disease. The pathophysiologic process remains incompletely understood, and no specific treatment is available. Dent disease is likely under-recognized. It needs to be included in the differential, especially in young males, presenting with recurrent kidney stones, proteinuria, and impaired renal function.
PubMed: 33163328
DOI: 10.5414/CNCS110198 -
Intractable & Rare Diseases Research Nov 2020The oculocerebrorenal syndrome of Lowe is a rare X-linked disease characterized by congenital cataracts, proximal renal tubulopathy, muscular hypotonia and mental...
The oculocerebrorenal syndrome of Lowe is a rare X-linked disease characterized by congenital cataracts, proximal renal tubulopathy, muscular hypotonia and mental impairment. This disease is caused by mutations in the gene encoding membrane bound inositol polyphosphate 5-phosphatase OCRL1. Here, we examined the gene of two Lowe syndrome patients and report two new missense mutations that affect the ASH domain involved in protein-protein interactions. Genomic DNA was extracted from peripheral blood of two non-related patients and their relatives. Exons and flanking intronic regions of were analyzed by direct sequencing. Several bioinformatics tools were used to assess the pathogenicity of the variants. The three-dimensional structure of wild-type and mutant ASH domains was modeled using the online server SWISS-MODEL. Clinical features suggesting the diagnosis of Lowe syndrome were observed in both patients. Genetic analysis revealed two novel missense variants, c.1907T>A (p.V636E) and c.1979A>C (p.H660P) in exon 18 of the gene confirming the clinical diagnosis in both cases. Variant c.1907T>A (p.V636E) was inherited from the patient's mother, while variant c.1979A>C (p.H660P) seems to have originated . Analysis with bioinformatics tools indicated that both variants are pathogenic. Both amino acid changes affect the structure of the OCRL1 ASH domain. In conclusion, the identification of two novel missense mutations located in the OCRL1 ASH domain may shed more light on the functional importance of this domain. We suggest that p.V636E and p.H660P cause Lowe syndrome by disrupting the interaction of OCRL1 with other proteins or by impairing protein stability.
PubMed: 33139981
DOI: 10.5582/irdr.2020.03092 -
American Journal of Physiology. Renal... Dec 2020Pathogenic variants in the gene, encoding the multiligand receptor megalin, cause a rare autosomal recessive syndrome: Donnai-Barrow/Facio-Oculo-Acoustico-Renal...
Pathogenic variants in the gene, encoding the multiligand receptor megalin, cause a rare autosomal recessive syndrome: Donnai-Barrow/Facio-Oculo-Acoustico-Renal (DB/FOAR) syndrome. Because of the rarity of the syndrome, the long-term consequences of the tubulopathy on human renal health have been difficult to ascertain, and the human clinical condition has hitherto been characterized as a benign tubular condition with asymptomatic low-molecular-weight proteinuria. We investigated renal function and morphology in a murine model of DB/FOAR syndrome and in patients with DB/FOAR. We analyzed glomerular filtration rate in mice by FITC-inulin clearance and clinically characterized six families, including nine patients with DB/FOAR and nine family members. Urine samples from patients were analyzed by Western blot analysis and biopsy materials were analyzed by histology. In the mouse model, we used histological methods to assess nephrogenesis and postnatal renal structure and contrast-enhanced magnetic resonance imaging to assess glomerular number. In megalin-deficient mice, we found a lower glomerular filtration rate and an increase in the abundance of injury markers, such as kidney injury molecule-1 and -acetyl-β-d-glucosaminidase. Renal injury was validated in patients, who presented with increased urinary kidney injury molecule-1, classical markers of chronic kidney disease, and glomerular proteinuria early in life. Megalin-deficient mice had normal nephrogenesis, but they had 19% fewer nephrons in early adulthood and an increased fraction of nephrons with disconnected glomerulotubular junction. In conclusion, megalin dysfunction, as present in DB/FOAR syndrome, confers an increased risk of progression into chronic kidney disease.
Topics: Adolescent; Adult; Animals; Child; Child, Preschool; Female; Genetic Predisposition to Disease; Genetic Variation; Humans; Kidney Glomerulus; Low Density Lipoprotein Receptor-Related Protein-2; Male; Mice; Mice, Knockout; Middle Aged; Renal Insufficiency, Chronic; Young Adult
PubMed: 33103447
DOI: 10.1152/ajprenal.00295.2020 -
BMC Nephrology Oct 2020Individuals of African descent are at higher risk of developing kidney disease than their European counterparts, and HIV infection is associated with increased risk of...
BACKGROUND
Individuals of African descent are at higher risk of developing kidney disease than their European counterparts, and HIV infection is associated with increased risk of nephropathy. Despite a safe renal profile in the clinical trials, long-term use of tenofovir disoproxil fumarate (TDF) has been associated with proximal renal tubulopathy although the underlying mechanisms remain undetermined. We aim to establish the prevalence of and risk factors for TDF-induced kidney tubular dysfunction (KTD) among HIV-I and II individuals treated with TDF in south-west Nigeria. Association between TDF-induced KTD and genetic polymorphisms in renal drug transporter genes and the APOL1 (Apolipoprotein L1) gene will be examined.
METHODS
This study has two phases. An initial cross-sectional study will screen 3000 individuals attending the HIV clinics in south-west Nigeria for KTD to determine the prevalence and risk factors. This will be followed by a case-control study of 400 KTD cases and 400 matched controls to evaluate single nucleotide polymorphism (SNP) associations. Data on socio-demographics, risk factors for kidney dysfunction and HIV history will be collected by questionnaire. Blood and urine samples for measurements of severity of HIV disease (CD4 count, viral load) and renal function (creatinine, eGFR, phosphate, uric acid, glucose) will also be collected. Utility of urinary retinol binding protein (RBP) and N-acetyl-beta-D-glucosaminidase (NAG) levels as surrogate markers of KTD will be evaluated. Genomic DNA will be extracted from whole blood and SNP analyses performed using the rhAMP SNP genotyping assays. Statistical analysis including univariate and multivariate logistic regression analyses will be performed to identify factors associated with KTD.
DISCUSSION
In spite of TDF being the most commonly used antiretroviral agent and a key component of many HIV treatment regimens, it has potential detrimental effects on the kidneys. This study will establish the burden and risk factors for TDF-induced KTD in Nigerians, and explore associations between KTD and polymorphisms in renal transporter genes as well as APOL1 risk variants. This study may potentially engender an approach for prevention as well as stemming the burden of CKD in sub-Saharan Africa where GDP per capita is low and budgetary allocation for health is inadequate.
Topics: Adult; Anti-HIV Agents; Black People; Case-Control Studies; Cross-Sectional Studies; Female; HIV Seropositivity; HIV-1; HIV-2; Humans; Kidney Diseases; Kidney Tubules; Male; Nigeria; Pharmacogenomic Testing; Polymorphism, Single Nucleotide; Prevalence; Research Design; Risk Factors; Socioeconomic Factors; Tenofovir; Viral Load
PubMed: 33066744
DOI: 10.1186/s12882-020-02082-3 -
Journal of Korean Medical Science Sep 2020Oxidative stress induced by chronic hyperglycemia is recognized as a significant mechanistic contributor to the development of diabetic kidney disease (DKD)....
BACKGROUND
Oxidative stress induced by chronic hyperglycemia is recognized as a significant mechanistic contributor to the development of diabetic kidney disease (DKD). Nonphagocytic nicotinamide adenine dinucleotide phosphate oxidase 4 (Nox4) is a major source of reactive oxygen species (ROS) in many cell types and in the kidney tissue of diabetic animals. We designed this study to explore the therapeutic potential of chloroquine (CQ) and amodiaquine (AQ) for inhibiting mitochondrial Nox4 and diabetic tubular injury.
METHODS
Human renal proximal tubular epithelial cells (hRPTCs) were cultured in high-glucose media (30 mM D-glucose), and diabetes was induced with streptozotocin (STZ, 50 mg/kg i.p. for 5 days) in male C57BL/6J mice. CQ and AQ were administered to the mice via intraperitoneal injection for 14 weeks.
RESULTS
CQ and AQ inhibited mitochondrial Nox4 and increased mitochondrial mass in hRPTCs under high-glucose conditions. Reduced mitochondrial ROS production after treatment with the drugs resulted in decreased endoplasmic reticulum (ER) stress, suppressed inflammatory protein expression and reduced cell apoptosis in hRPTCs under high-glucose conditions. Notably, CQ and AQ treatment diminished Nox4 activation and ER stress in the kidneys of STZ-induced diabetic mice. In addition, we observed attenuated inflammatory protein expression and albuminuria in STZ-induced diabetic mice after CQ and AQ treatment.
CONCLUSION
We substantiated the protective actions of CQ and AQ in diabetic tubulopathy associated with reduced mitochondrial Nox4 activation and ER stress alleviation. Further studies exploring the roles of mitochondrial Nox4 in the pathogenesis of DKD could suggest new therapeutic targets for patients with DKD.
Topics: Amodiaquine; Animals; Apoptosis; Cells, Cultured; Chloroquine; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Endoplasmic Reticulum Stress; Glucose; Humans; Kidney Tubules, Proximal; Male; Mice; Mice, Inbred C57BL; Mitochondria; NADPH Oxidase 4; Reactive Oxygen Species
PubMed: 32924342
DOI: 10.3346/jkms.2020.35.e305 -
Human Genetics Mar 2021Dent disease is a rare genetic proximal tubulopathy which is under-recognized. Its phenotypic heterogeneity has led to several different classifications of the same... (Review)
Review
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.
Topics: Chloride Channels; Dent Disease; Genetic Heterogeneity; Humans; Mutation; Phenotype; Phosphoric Monoester Hydrolases
PubMed: 32860533
DOI: 10.1007/s00439-020-02219-2