Oral alkalinizing supplementation suppressed intrarenal reactive oxidative stress in mild-stage chronic kidney disease: a randomized cohort study.

BACKGROUND: The beneficial effects of oral supplements with alkalinizing agents in patients with chronic kidney disease (CKD) have been limited to the severe stages. We investigated whether two types of supplements, sodium bicarbonate (SB) and potassium citrate/sodium citrate (PCSC), could maintain renal function in patients with mild-stage CKD. METHODS: This was a single-center, open-labeled, randomized cohort trial. Study participants with CKD stages G2, G3a, and G3b were enrolled between March 2013 and January 2019 and randomly assigned by stratification according to age, sex, estimated glomerular filtration rate (eGFR), and diabetes. They were followed up for 6 months (short-term study) for the primary endpoints and extended to 2 years (long-term study) for the secondary endpoints. Supplementary doses were adjusted to achieve an early morning urinary pH of 6.8-7.2. We observed renal dysfunction or new-onset cerebrovascular disease and evaluated urinary surrogate markers for renal injury. RESULTS: Overall, 101 participants were registered and allocated to three groups: standard (n = 32), SB (n = 34), and PCSC (n = 35). Two patients in the standard group attained the primary endpoints (renal stones and overt proteinuria) but were not statistically significant. There was one patient in the standard reduced eGFR during the long-term study (p = 0.042 by ANOVA). SB increased proteinuria (p = 0.0139, baseline vs. 6 months), whereas PCSC significantly reduced proteinuria (p = 0.0061, baseline vs. 1 year, or p = 0.0186, vs. 2 years) and urinary excretion of 8-hydroxy-2'-deoxyguanosine (p = 0.0481, baseline vs. 6 months). CONCLUSION: This study is the first to report supplementation of PCSC reduced intrarenal oxidative stress in patients with mild-stage CKD.

Application of Electrolyzed Hydrogen Water for Management of Chronic Kidney Disease and Dialysis Treatment-Perspective View.

Chronic kidney disease (CKD), which is globally on the rise, has become an urgent challenge from the perspective of public health, given its risk factors such as end-stage renal failure, cardiovascular diseases, and infections. The pathophysiology of CKD, including dialysis patients, is deeply associated with enhanced oxidative stress in both the kidneys and the entire body. Therefore, the introduction of a safe and widely applicable antioxidant therapy is expected as a measure against CKD. Electrolyzed hydrogen water (EHW) generated through the electrolysis of water has been confirmed to possess chemical antioxidant capabilities. In Japan, devices producing this water have become popular for household drinking water. In CKD model experiments conducted to date, drinking EHW has been shown to suppress the progression of kidney damage related to hypertension. Furthermore, clinical studies have reported that systemic oxidative stress in patients undergoing dialysis treatment using EHW is suppressed, leading to a reduction in the incidence of cardiovascular complications. In the future, considering EHW as one of the comprehensive measures against CKD holds significant importance. The medical utility of EHW is believed to be substantial, and further investigation is warranted.

Estimated Glomerular Filtration Rate, Albuminuria, and Adverse Outcomes: An Individual-Participant Data Meta-Analysis.

Importance: Chronic kidney disease (low estimated glomerular filtration rate [eGFR] or albuminuria) affects approximately 14% of adults in the US. Objective: To evaluate associations of lower eGFR based on creatinine alone, lower eGFR based on creatinine combined with cystatin C, and more severe albuminuria with adverse kidney outcomes, cardiovascular outcomes, and other health outcomes. Design, Setting, and Participants: Individual-participant data meta-analysis of 27 503 140 individuals from 114 global cohorts (eGFR based on creatinine alone) and 720 736 individuals from 20 cohorts (eGFR based on creatinine and cystatin C) and 9 067 753 individuals from 114 cohorts (albuminuria) from 1980 to 2021. Exposures: The Chronic Kidney Disease Epidemiology Collaboration 2021 equations for eGFR based on creatinine alone and eGFR based on creatinine and cystatin C; and albuminuria estimated as urine albumin to creatinine ratio (UACR). Main Outcomes and Measures: The risk of kidney failure requiring replacement therapy, all-cause mortality, cardiovascular mortality, acute kidney injury, any hospitalization, coronary heart disease, stroke, heart failure, atrial fibrillation, and peripheral artery disease. The analyses were performed within each cohort and summarized with random-effects meta-analyses. Results: Within the population using eGFR based on creatinine alone (mean age, 54 years [SD, 17 years]; 51% were women; mean follow-up time, 4.8 years [SD, 3.3 years]), the mean eGFR was 90 mL/min/1.73 m2 (SD, 22 mL/min/1.73 m2) and the median UACR was 11 mg/g (IQR, 8-16 mg/g). Within the population using eGFR based on creatinine and cystatin C (mean age, 59 years [SD, 12 years]; 53% were women; mean follow-up time, 10.8 years [SD, 4.1 years]), the mean eGFR was 88 mL/min/1.73 m2 (SD, 22 mL/min/1.73 m2) and the median UACR was 9 mg/g (IQR, 6-18 mg/g). Lower eGFR (whether based on creatinine alone or based on creatinine and cystatin C) and higher UACR were each significantly associated with higher risk for each of the 10 adverse outcomes, including those in the mildest categories of chronic kidney disease. For example, among people with a UACR less than 10 mg/g, an eGFR of 45 to 59 mL/min/1.73 m2 based on creatinine alone was associated with significantly higher hospitalization rates compared with an eGFR of 90 to 104 mL/min/1.73 m2 (adjusted hazard ratio, 1.3 [95% CI, 1.2-1.3]; 161 vs 79 events per 1000 person-years; excess absolute risk, 22 events per 1000 person-years [95% CI, 19-25 events per 1000 person-years]). Conclusions and Relevance: In this retrospective analysis of 114 cohorts, lower eGFR based on creatinine alone, lower eGFR based on creatinine and cystatin C, and more severe UACR were each associated with increased rates of 10 adverse outcomes, including adverse kidney outcomes, cardiovascular diseases, and hospitalizations.

Type II Cryoglobulinemic Membranoproliferative Glomerulonephritis Caused by Mucosa-associated Lymphoid Tissue Lymphoma.

A 67-year-old man complained of lower limb edema with a purpuric skin rash. Laboratory tests revealed proteinuria, elevated serum creatinine levels, and low serum albumin levels. The patient was also positive for cryoglobulin in serum, immunoglobulin (Ig) M gammopathy, hypocomplementemia, and rheumatoid factor. He was negative for anti-hepatitis C virus antibodies. A pathological analysis of the renal tissue revealed membranoproliferative glomerulonephritis, common histological features of cryoglobulinemic vasculitis (CV), and mucosa-associated lymphoid tissue lymphoma invasion. Although hematologic malignancy is a rare cause of type II CV, these clinical findings suggest that mucosa-associated lymphoid tissue lymphoma (MALT) lymphoma may have been the cause in the present case.

Cerebellar haemorrhage triggered by allergic reaction to maintenance haemodialysis in a patient with eosinophilia.

We report a case of eosinophilia and an allergic reaction that caused a cerebellar haemorrhage.An woman in her 80s presented with headache, dyspnoea and vomiting with severe hypotension soon after switching the dialysis membrane, and a CT scan revealed cerebellar haemorrhage. In the subsequent clinical course, the patient developed an allergic reaction to multiple membranes and required corticosteroids to continue haemodialysis (HD). Pre-existing eosinophilia is a risk factor for cerebral infarctions and dialysis membrane allergy, which is a common feature in patients undergoing HD. Membrane switching and corticosteroid therapy must be considered in case of multiple membrane allergies.

Long-term effectiveness of a primary care practice facilitation program for chronic kidney disease management: an extended follow-up of a cluster-randomized FROM-J study.

BACKGROUND: Practice facilitation program by multidisciplinary care for primary care physicians (PCPs) is expected to improve chronic kidney disease (CKD) outcomes, but there is no clear evidence of its long-term effectiveness. We have previously performed a cluster-randomized controlled trial for 3.5 years (the Frontier of Renal Outcome Modifications in Japan (FROM-J) study) with two arms-group A without the program and group B with the program. We aimed to assess the long-term effectiveness of the practice facilitation program on CKD outcomes via an extended 10-year follow-up of the FROM-J study. METHODS: We enrolled patients who were in the FROM-J study. The primary composite endpoint comprised cardiovascular disease (CVD), renal replacement therapy initiation and a 50% decrease in the estimated glomerular filtration rate (eGFR). The secondary endpoints were survival rate, eGFR decline rate and collaboration rate between PCPs and nephrologists. RESULTS: The occurrence of the primary composite endpoint tended to be lower in group B (group A: 27.1% versus group B: 22.1%, P = 0.051). Furthermore, CVD incidence was remarkably lower in group B (group A: 10.5% versus group B: 6.4%, P = 0.001). Although both mortality and the rate of eGFR decline were identical between both groups, the eGFR decline rate was significantly better in group B than in group A only in patients with stage G3a at enrollment (group A: 2.35 ± 3.87 mL/min/1.73 m2/year versus group B: 1.68 ± 2.98 mL/min/1.73 m2/year, P = 0.02). The collaboration rate was higher in group B. CONCLUSIONS: The CKD practice facilitation program for PCPs reliably decreases CVD events and may reduce the progression of cases to end-stage kidney disease.

Marked reduction of proteinuria after removal of a growth hormone-producing pituitary adenoma in a patient with focal segmental glomerulosclerosis: a case report and literature review.

Focal segmental glomerulosclerosis is a rare complication of acromegaly. A 74-year-old man was found to have acromegaly features such as enlargement of the forehead, nose, and hands. Laboratory tests showed a urine protein/creatinine ratio of 3.16 g/gCr and serum creatinine of 1.34 mg/dL. The levels of growth hormone and insulin-like growth factor I were markedly elevated, and the growth hormone level was not suppressed after 75 g oral glucose loading. Magnetic resonance imaging revealed a pituitary tumor with a diameter of 1.2 cm. Renal biopsy confirmed the diagnosis of focal segmental glomerulosclerosis. Transsphenoidal resection of the pituitary tumor led to remission of acromegaly and reduction in proteinuria highlighting the causal link between growth hormone overproduction and proteinuria. Treatment of acromegaly may be effective for acromegaly-associated focal segmental glomerulosclerosis.

Effect of Low-Density Lipoprotein Apheresis on Quality of Life in Patients with Diabetes, Proteinuria, and Hypercholesterolemia.

INTRODUCTION: Treating diabetic nephropathy with low-density lipoprotein (LDL) apheresis reduces proteinuria and improves prognosis. However, its impact on patients' quality of life (QoL) is unclear. This study evaluated the effect of LDL apheresis on QoL in patients with diabetes, proteinuria, and hypercholesterolemia. METHODS: In this nationwide multicenter prospective study, we enrolled 40 patients with diabetes. Inclusion criteria were proteinuria (defined as an albumin/creatinine ratio ≥3 g/g), serum creatinine levels <2 mg/dL, and serum LDL ≥120 mg/dL despite drug treatment. LDL apheresis was performed 6-12 times within 12 weeks. The 36-item Short Form Health Survey (SF-36) was used to analyze QoL. RESULTS: The study enrolled 35 patients (27 men and 8 women; mean age 58.9 ± 11.9 years). A comparison of baseline SF-36 values with those at the end of the course of apheresis found an improvement in the mean physical component summary (37.9 ± 11.4 vs. 40.6 ± 10.5, p = 0.051) and a significant increase in the mean mental component summary (MCS) (49.4 ± 8.4 vs. 52.5 ± 10.9, p = 0.026). A multivariable linear regression analysis revealed a history of coronary heart disease negatively correlated with the MCS increase at the end of the course of apheresis (ß coefficient -6.935, 95% confidence interval, 13.313 to-0.556, p = 0.034). CONCLUSION: Our results suggest that LDL apheresis may improve the mental and physical QoL in patients with diabetes, proteinuria, and hypercholesterolemia.

Hemodialysis Record Sharing: Solution for Work Burden Reduction and Disaster Preparedness.

BACKGROUND: After the Great East Japan Earthquake in 2011, backup systems for clinical information were launched in Japan. The system in Miyagi Prefecture called the Miyagi Medical and Welfare Information Network (MMWIN) is used as a health information exchange network to share clinical information among various medical facilities for patients who have opted in. Hospitals and clinics specializing in chronic renal failure require patients' data and records during hemodialysis to facilitate communication in daily clinical activity and preparedness for disasters. OBJECTIVE: This study aimed to facilitate the sharing of clinical data of patients undergoing hemodialysis among different hemodialysis facilities. METHODS: We introduced a document-sharing system to make hemodialysis reports available on the MMWIN. We also recruited hospitals and clinics to share the hemodialysis reports of their patients and promoted the development of a network between emergency and dialysis clinics. RESULTS: In addition to basic patient information as well as information on diagnosis, prescription, laboratory data, hospitalization, allergy, and image data from different facilities, specific information about hemodialysis is available, as well as a backup of indispensable information in preparation for disasters. As of June 1, 2021, 12 clinics and 10 hospitals of 68 dialysis facilities in Miyagi participated in the MMWIN. The number of patients who underwent hemodialysis in Miyagi increased by more than 40%. CONCLUSIONS: Our backup system successfully developed a network of hemodialysis facilities. We have accumulated data that are beneficial to prevent the fragmentation of patient information and would be helpful in transferring patients efficiently during unpredictable disasters.

Coagulation Influencing Liberation from Respiratory Support in Patients with Coronavirus Disease 2019: A Retrospective, Observational Study.

BACKGROUND: Patients with coronavirus disease 2019 (COVID-19) occasionally develop respiratory failure and coagulopathy. We aimed to determine whether coagulation abnormalities at admission and during the course of hospitalization can predict the liberation from respiratory support in critically ill patients with COVID-19 by combining the results of rotational thromboelastometry (ROTEM) with standard laboratory tests. METHODS: This single-center, retrospective, observational study included 31 consecutive adult patients with COVID-19 who were admitted to the intensive care unit (ICU) and who required respiratory support between April 2021 and August 2021. We divided the patients into two groups according to the liberation from respiratory support and analyzed the differences between the groups. RESULTS: There were 20 patients in the liberation group and 11 in the non-liberation group. There were no significant differences in the overt disseminated intravascular coagulation scores or abnormal counts in the ROTEM parameters at admission between groups, although there was a significant difference in the highest score in the ICU. The Sequential Organ Failure Assessment and sepsis-induced coagulopathy scores were significantly different between both groups at admission and at the time when the highest values were reported during the ICU stay. CONCLUSIONS: High sepsis-induced coagulopathy scores at admission to the ICU were found to be useful predictors of difficulties in the liberation from respiratory support in patients with severe COVID-19. However, increased overt disseminated intravascular coagulation scores and abnormal counts in the ROTEM parameters during the ICU stay were associated with difficulties in the liberation from respiratory support.

Methylglyoxal Induces Inflammation, Metabolic Modulation and Oxidative Stress in Myoblast Cells.

Uremic sarcopenia is a serious clinical problem associated with physical disability and increased morbidity and mortality. Methylglyoxal (MG) is a highly reactive, dicarbonyl uremic toxin that accumulates in the circulatory system in patients with chronic kidney disease (CKD) and is related to the pathology of uremic sarcopenia. The pathophysiology of uremic sarcopenia is multifactorial; however, the details remain unknown. We investigated the mechanisms of MG-induced muscle atrophy using mouse myoblast C2C12 cells, focusing on intracellular metabolism and mitochondrial injury. We found that one of the causative pathological mechanisms of uremic sarcopenia is metabolic flow change to fatty acid synthesis with MG-induced ATP shortage in myoblasts. Evaluation of cell viability revealed that MG showed toxic effects only in myoblast cells, but not in myotube cells. Expression of mRNA or protein analysis revealed that MG induces muscle atrophy, inflammation, fibrosis, and oxidative stress in myoblast cells. Target metabolomics revealed that MG induces metabolic alterations, such as a reduction in tricarboxylic acid cycle metabolites. In addition, MG induces mitochondrial morphological abnormalities in myoblasts. These changes resulted in the reduction of ATP derived from the mitochondria of myoblast cells. Our results indicate that MG is a pathogenic factor in sarcopenia in CKD.

Concomitant pleuritis and pericarditis developing during glucocorticoid therapy: a case report on granulomatosis with polyangiitis.

Granulomatosis with polyangiitis is an anti-neutrophil cytoplasmic antibody-associated vasculitis that manifests in various ways by affecting the small-sized vessels in multiple organs. Acute pleuritis and pericarditis are both rare among the different manifestations of granulomatosis with polyangiitis. The symptoms in each of the organs are often apparent at the time of diagnosis and tend to diminish with treatment. Organ damage and progression of the disease during treatment are uncommon. We encountered a patient with granulomatosis with polyangiitis who, after starting intravenous methylprednisolone pulse therapy, concurrently developed acute pleuritis and pericarditis. The patient was a 47-year-old Japanese man with myalgia in whom kidney dysfunction, proteinase 3-anti-neutrophil cytoplasmic antibody positivity, and a lung mass were detected. Granulomatosis with polyangiitis was diagnosed pathologically from a lung and a kidney biopsy. Acute pleuritis and pericarditis, which developed after the first course of intravenous methylprednisolone pulse therapy, both resolved following the second course. The present report indicates that secondary serositis such as pleuritis and pericarditis can develop in patients with granulomatosis with polyangiitis even during glucocorticoid therapy.

Glomerulonephritis Associated with Infective Endocarditis Showing Serological Positivity for PR3-anti-neutrophil Cytoplasmic Antibody and Anti-glomerular Basement Membrane Antibody.

We herein report a case of crescentic glomerulonephritis (GN) associated with infective endocarditis (IE). A 61-year-old-woman presented with a fever and renal dysfunction and was diagnosed with IE. The patient was positive for proteinase 3-anti-neutrophil cytoplasmic antibody (PR3-ANCA) and anti-glomerular basement membrane (GBM) antibodies. Renal biopsy findings showed crescentic GN with isolated deposition of C3c, a serum conversion product of complement C3. Given these clinical findings, the patient was diagnosed with infective endocardis (IE)-associated GN. Antibiotic therapy was continued without immunosuppressive agents. After the initiation of the antibiotics, the fever resolved, and the renal function gradually recovered. This case highlights the notion that laboratory findings should be carefully evaluated with reference to other findings.

What's New in the Molecular Mechanisms of Diabetic Kidney Disease: Recent Advances.

Diabetic kidney disease (DKD) is the leading cause of chronic kidney disease, including end-stage kidney disease, and increases the risk of cardiovascular mortality. Although the treatment options for DKD, including angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, sodium-glucose cotransporter 2 inhibitors, and mineralocorticoid receptor antagonists, have advanced, their efficacy is still limited. Thus, a deeper understanding of the molecular mechanisms of DKD onset and progression is necessary for the development of new and innovative treatments for DKD. The complex pathogenesis of DKD includes various different pathways, and the mechanisms of DKD can be broadly classified into inflammatory, fibrotic, metabolic, and hemodynamic factors. Here, we summarize the recent findings in basic research, focusing on each factor and recent advances in the treatment of DKD. Collective evidence from basic and clinical research studies is helpful for understanding the definitive mechanisms of DKD and their regulatory systems. Further comprehensive exploration is warranted to advance our knowledge of the pathogenesis of DKD and establish novel treatments and preventive strategies.

A massive natural disaster, the Great East Japan Earthquake, and the incidence of dialysis due to end-stage kidney disease.

BACKGROUND: Disaster-related stress can increase blood pressure and the incidence of cardiovascular diseases. However, the role of massive disasters in the development of end-stage kidney disease (ESKD) remains unknown. We investigated the incidence and different causes of dialysis initiation in patients with chronic kidney disease in a city affected by the Great East Japan Earthquake. METHODS: This was a single-center, retrospective observational study. All patients who initiated or were treated with dialysis at Kesennuma City Hospital between 2007 and 2020 were enrolled. The year of dialysis initiation was retrospectively determined based on the initiation date. The causative renal diseases that led to the need for dialysis initiation were divided into four groups: diabetic nephropathy, hypertensive renal disease, glomerulonephritis, and others. RESULTS: Age at dialysis initiation differed significantly among the four groups (p = 0.0262). There was a significant difference in the numbers of the four groups before and after the Great East Japan Earthquake (p = 0.0193). The age of hypertensive renal disease patients was significantly higher than those of patients with diabetic nephropathy (p = 0.0070) and glomerulonephritis (p = 0.0386) after the disaster. The increasing number of dialysis initiations after the Great East Japan Earthquake appeared to be associated with changes in hypertensive renal diseases; the number peaked after 10 years. CONCLUSIONS: There was an increase in the number of dialysis initiations, especially caused by hypertensive renal diseases, for up to 10 years after the Great East Japan Earthquake.

Development of a delirium predictive model for adult trauma patients in an emergency and critical care center: a retrospective study.

BACKGROUND: Delirium has been shown to prolong the length of intensive care unit stay, hospitalization, and duration of ventilatory control, in addition to increasing the use of sedatives and increasing the medical costs. Although there have been a number of reports referring to risk factors for the development of delirium, no model has been developed to predict delirium in trauma patients at the time of admission. This study aimed to create a scoring system that predicts delirium in trauma patients. METHODS: In this single-center, retrospective, observational study, trauma patients aged 18 years and older requiring hospitalization more than 48 hours were included and divided into the development and validation cohorts. Univariate analysis was performed in the development cohort to identify factors significantly associated with prediction of delirium. The final scoring system for predicting delirium was developed using multivariate analysis and internal validation was performed. RESULTS: Of the 308 patients in the development cohort, 91 developed delirium. Clinical Frailty Score, fibrin/fibrinogen degradation products, low body mass index, lactate level, and Glasgow Coma Scale score were independently associated with the development of delirium. We developed a scoring system using these factors and calculated the delirium predictive score, which had an area under the curve of 0.85. In the validation cohort, 46 of 206 patients developed delirium. The area under the curve for the validation cohort was 0.86, and the calibration plot analysis revealed the scoring system was well calibrated in the validation cohort. DISCUSSION: This scoring system for predicting delirium in trauma patients consists of only five risk factors. Delirium prediction at the time of admission may be useful in clinical practice. LEVEL OF EVIDENCE: Prognostic and epidemiological, level III.

Coagulation, Protease-Activated Receptors, and Diabetic Kidney Disease: Lessons from eNOS-Deficient Mice.

Endothelial nitric oxide synthase (eNOS) dysfunction is known to exacerbate the progression and prognosis of diabetic kidney disease (DKD). One of the mechanisms through which this is achieved is that low eNOS levels are associated with hypercoagulability, which promotes kidney injury. In the extrinsic coagulation cascade, the tissue factor (factor III) and downstream coagulation factors, such as active factor X (FXa), exacerbate inflammation through activation of the protease-activated receptors (PARs). Recently, it has been shown that the lack of or reduced eNOS expression in diabetic mice, as a model of advanced DKD, increases renal tissue factor levels and PAR1 and 2 expression in their kidneys. Furthermore, pharmaceutical inhibition or genetic deletion of coagulation factors or PARs ameliorated inflammation in DKD in mice lacking eNOS. In this review, we summarize the relationship between eNOS, coagulation, and PARs and propose a novel therapeutic option for the management of patients with DKD.

Myeloid cell-derived coagulation tissue factor is associated with renal tubular damage in mice fed an adenine diet.

Patients with chronic kidney disease (CKD) commonly exhibit hypercoagulability. Increased levels of uremic toxins cause thrombogenicity by increasing tissue factor (TF) expression and activating the extrinsic coagulation cascade. TF is induced in monocytes and macrophages under pathological conditions, such as inflammatory diseases. However, the role of monocyte myeloid cell TF in CKD progression remains unclear. We aimed to clarify this issue, and the present study found that patients with CKD had elevated levels of D-dimer, a marker of fibrin degradation, which was associated with decreased estimated glomerular filtration rate and increased serum levels of uremic toxins, such as indoxyl sulfate. In vitro studies showed that several uremic toxins increased cellular TF levels in monocytic THP-1 cells. Mice with TF specifically deleted in myeloid cells were fed an adenine diet to cause uremic kidney injury. Myeloid TF deletion reduced tubular injury and pro-inflammatory gene expression in the kidneys of adenine-induced CKD but did not improve renal function as measured by plasma creatinine or blood urea nitrogen. Collectively, our findings suggest a novel concept of pathogenesis of coagulation-mediated kidney injury, in which elevated TF levels in monocytes under uremic conditions is partly involved in the development of CKD.

Renal Injuries in Primary Aldosteronism: Quantitative Histopathological Analysis of 19 Patients With Primary Adosteronism.

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Genetic Background and Clinicopathologic Features of Adult-onset Nephronophthisis.

INTRODUCTION: Recently, nephronophthisis (NPH) has been considered a monogenic cause of end-stage renal disease (ESRD) in adults. However, adult-onset NPH is difficult to accurately diagnose and has not been reported in a cohort study. In this study, we assessed the genetic background and clinicopathologic features of adult NPH. METHODS: We investigated 18 sporadic adult patients who were suspected as having NPH by renal biopsy. We analyzed 69 genes that cause hereditary cystic kidney disease and compared clinicopathologic findings between patients with and without pathogenic mutations in NPH-causing genes. RESULTS: Seven of 18 patients had pathogenic NPH-causing mutations in NPHP1, NPHP3, NPHP4, or CEP164. Compared with patients without pathogenic mutations, those with pathogenic mutations were significantly younger but did not significantly differ in the classic NPH pathologic findings, such as tubular cysts. On the other hand, the number of tubules with thick tubular basement membrane (TBM) duplication, which was defined as >10-µm thickness, was significantly higher in patients with genetically proven adult NPH than in those without pathogenic mutations. α-Smooth muscle actin (α-SMA)-positive myofibroblasts were detected inside thick TBM duplication. CONCLUSIONS: In adult patients with NPH, thick TBM duplication was the specific finding. Our analysis also suggested that older patients tended to have no pathogenic mutations, even when they were suspected to have NPH by renal biopsy. These findings could be the novel clinical clue for the diagnosis of NPH in adult patients.