Vascular Calcification Is Accelerated by Hyponatremia and Low Osmolality.

BACKGROUND: Hyponatremia, frequently observed in patients with chronic kidney disease, is associated with increased cardiovascular morbidity and mortality. Hyponatremia or low osmolality induces oxidative stress and cell death, both of which accelerate vascular calcification (VC), a critical phenotype in patients with chronic kidney disease. Whether hyponatremia or low osmolality plays a role in the pathogenesis of VC is unknown. METHODS: Human vascular smooth muscle cells (VSMCs) and mouse aortic rings were cultured in various osmotic conditions and calcifying medium supplemented with high calcium and phosphate. The effects of low osmolality on phenotypic change and oxidative stress in the cultured VSMCs were examined. Microarray analysis was conducted to determine the main signaling pathway of osmolality-related VC. The transcellular sodium and calcium ions flux across the VSMCs were visualized by live imaging. Furthermore, the effect of osmolality on calciprotein particles (CPPs) was investigated. Associations between arterial intimal calcification and hyponatremia or low osmolality were examined by a cross-sectional study using human autopsy specimens obtained in the Hisayama Study. RESULTS: Low osmolality exacerbated calcification of the ECM (extracellular matrix) of cultured VSMCs and mouse aortic rings. Oxidative stress and osteogenic differentiation of VSMCs were identified as the underlying mechanisms responsible for low osmolality-induced VC. Microarray analysis showed that low osmolality activated the Rac1 (Ras-related C3 botulinum toxin substrate 1)-Akt (protein kinase B) pathway and reduced NCX1 (Na-Ca exchanger 1) expression. Live imaging showed synchronic calcium ion efflux and sodium ion influx via NCX1 when extracellular sodium ion concentrations were increased. An NCX1 inhibitor promoted calcifying media-induced VC by reducing calcium ion efflux. Furthermore, low osmolality accelerated the generation and maturation steps of CPPs. The cross-sectional study of human autopsy specimens showed that hyponatremia and low osmolality were associated with a greater area of arterial intimal calcification. CONCLUSIONS: Hyponatremia and low osmolality promote VC through multiple cellular processes, including the Rac1-Akt pathway activation.

Formation of clustered DNA damage in vivo upon irradiation with ionizing radiation: Visualization and analysis with atomic force microscopy.

SignificanceDNA damage causes loss of or alterations in genetic information, resulting in cell death or mutations. Ionizing radiations produce local, multiple DNA damage sites called clustered DNA damage. In this study, a complete protocol was established to analyze the damage complexity of clustered DNA damage, wherein damage-containing genomic DNA fragments were selectively concentrated via pulldown, and clustered DNA damage was visualized by atomic force microscopy. It was found that X-rays and Fe ion beams caused clustered DNA damage. Fe ion beams also produced clustered DNA damage with high complexity. Fe ion beam-induced complex DNA double-strand breaks (DSBs) containing one or more base lesion(s) near the DSB end were refractory to repair, implying their lethal effects.

Granzyme K- and amphiregulin-expressing cytotoxic T cells and activated extrafollicular B cells are potential drivers of IgG4-related disease.

BACKGROUND: IgG4-related disease (IgG4-RD), an example of a type I immune disease, is an immune-mediated fibrotic disorder characterized by dysregulated resolution of severe inflammation and wound healing. However, truly dominant or pathognomonic autoantibodies related to IgG4-RD are not identified. OBJECTIVE: We sought to perform single-cell RNA sequencing and T-cell receptor and B-cell receptor sequencing to obtain a comprehensive, unbiased view of tissue-infiltrating T and B cells. METHODS: We performed unbiased single-cell RNA-sequencing analysis for the transcriptome and T-cell receptor sequencing and B-cell receptor sequencing on sorted CD3+ T or CD19+ B cells from affected tissues of patients with IgG4-RD. We also conducted quantitative analyses of CD3+ T-cell and CD19+ B-cell subsets in 68 patients with IgG4-RD and 30 patients with Sjögren syndrome. RESULTS: Almost all clonally expanded T cells in these lesions were either Granzyme K (GZMK)-expressing CD4+ cytotoxic T cells or GZMK+CD8+ T cells. These GZMK-expressing cytotoxic T cells also expressed amphiregulin and TGF-ß but did not express immune checkpoints, and the tissue-infiltrating CD8+ T cells were phenotypically heterogeneous. MKI67+ B cells and IgD-CD27-CD11c-CXCR5- double-negative 3 B cells were clonally expanded and infiltrated affected tissue lesions. GZMK+CD4+ cytotoxic T cells colocalized with MKI67+ B cells in the extrafollicular area from affected tissue sites. CONCLUSIONS: The above-mentioned cells likely participate in T-B collaborative events, suggesting possible avenues for targeted therapies. Our findings were validated using orthogonal approaches, including multicolor immunofluorescence and the use of comparator disease groups, to support the central role of cytotoxic CD4+ and CD8+ T cells expressing GZMK, amphiregulin, and TGF-ß in the pathogenesis of inflammatory fibrotic disorders.

Proprotein Convertase Subtilisin/Kexin 9 (PCSK9) Promotes Macrophage Activation via LDL Receptor-Independent Mechanisms.

BACKGROUND: Activated macrophages contribute to the pathogenesis of vascular disease. Vein graft failure is a major clinical problem with limited therapeutic options. PCSK9 (proprotein convertase subtilisin/kexin 9) increases low-density lipoprotein (LDL)-cholesterol levels via LDL receptor (LDLR) degradation. The role of PCSK9 in macrophage activation and vein graft failure is largely unknown, especially through LDLR-independent mechanisms. This study aimed to explore a novel mechanism of macrophage activation and vein graft disease induced by circulating PCSK9 in an LDLR-independent fashion. METHODS: We used Ldlr-/- mice to examine the LDLR-independent roles of circulating PCSK9 in experimental vein grafts. Adeno-associated virus (AAV) vector encoding a gain-of-function mutant of PCSK9 (rAAV8/D377Y-mPCSK9) induced hepatic PCSK9 overproduction. To explore novel inflammatory targets of PCSK9, we used systems biology in Ldlr-/- mouse macrophages. RESULTS: In Ldlr-/- mice, AAV-PCSK9 increased circulating PCSK9, but did not change serum cholesterol and triglyceride levels. AAV-PCSK9 promoted vein graft lesion development when compared with control AAV. In vivo molecular imaging revealed that AAV-PCSK9 increased macrophage accumulation and matrix metalloproteinase activity associated with decreased fibrillar collagen, a molecular determinant of atherosclerotic plaque stability. AAV-PCSK9 induced mRNA expression of the pro-inflammatory mediators IL-1ß (interleukin-1 beta), TNFα (tumor necrosis factor alpha), and MCP-1 (monocyte chemoattractant protein-1) in peritoneal macrophages underpinned by an in vitro analysis of Ldlr-/- mouse macrophages stimulated with endotoxin-free recombinant PCSK9. A combination of unbiased global transcriptomics and new network-based hyperedge entanglement prediction analysis identified the NF-κB (nuclear factor-kappa B) signaling molecules, lectin-like oxidized LOX-1 (LDL receptor-1), and SDC4 (syndecan-4) as potential PCSK9 targets mediating pro-inflammatory responses in macrophages. CONCLUSIONS: Circulating PCSK9 induces macrophage activation and vein graft lesion development via LDLR-independent mechanisms. PCSK9 may be a potential target for pharmacologic treatment for this unmet medical need.

Factors affecting the sodium-glucose cotransporter 2 inhibitors-related initial decline in glomerular filtration rate and its possible effect on kidney outcome in chronic kidney disease with type 2 diabetes: The Japan Chronic Kidney Disease Database.

AIM: Sodium-glucose cotransporter 2 (SGLT2) inhibitors often cause a transient decrease in glomerular filtration rate (GFR) shortly after the initiation, referred to as the 'initial drop'. However, the clinical significance of this initial drop in real-world practice remains unclear. MATERIALS AND METHODS: Using the nationwide Japan Chronic Kidney Disease Database, we examined factors that affected the initial drop, in patients with chronic kidney disease (CKD) and type 2 diabetes mellitus (T2DM). We also evaluated the effects of the initial drop on a composite kidney outcome (a decline in GFR of ≥50% or progression to end-stage kidney disease). RESULTS: Data from 2053 patients with CKD and T2DM newly prescribed an SGLT2 inhibitor were analysed. The follow-up period after SGLT2 inhibitor administration was 1015 days (interquartile range: 532, 1678). Multivariate linear regression models revealed that the concomitant use of the renin-angiotensin system inhibitors and diuretics, urinary protein levels ≥2+, and changes in GFR before the initiation of the SGLT2 inhibitor were associated with a larger initial GFR decline (ß = -0.609, p = .039; ß = -2.298, p < .001; ß = -0.936, p = .048; ß = -0.079, p < .001, respectively). Patients in the quartile with the largest initial GFR decline experienced a higher incidence of the subsequent composite kidney outcome than those in the other quartiles (p < .001). CONCLUSIONS: The concomitant use of renin-angiotensin system inhibitors and diuretics, higher urine protein levels and pre-treatment GFR changes were associated with a larger initial GFR decline. Of these factors, the use of a diuretic had the largest effect. Furthermore, patients with CKD and T2DM experiencing an excessive initial GFR drop might be at a higher risk of adverse kidney outcomes.

History of fragility fracture is associated with cardiovascular mortality in hemodialysis patients: the Q-Cohort study.

INTRODUCTION: In patients undergoing dialysis, major bone fracture is associated with a high risk of mortality, including death of cardiovascular (CV) origin. In the present study, we aimed to determine whether a history of fragility fracture is a predictor of CV death in patients undergoing hemodialysis with long-term follow-up. MATERIALS AND METHODS: In total, 3499 patients undergoing hemodialysis were analyzed for 10 years. We evaluated the history of fragility fracture in each patient at enrollment. The primary outcome was CV death. A Cox proportional hazard model and a competing risk approach were applied to determine the association between a history of fragility fracture and CV death. RESULTS: A total of 346 patients had a history of fragility fracture at enrollment. During a median follow-up of 8.8 years, 1730 (49.4%) patients died. Among them, 621 patients experienced CV death. Multivariable Cox analyses after adjustment for confounding variables showed that a history of fragility fracture was associated with CV death (hazard ratio, 1.47; 95% confidence interval, 1.16-1.85). In the Fine-Gray regression model, a history of fragility fracture was an independent risk factor for CV death (subdistribution hazard ratio, 1.36; 95% confidence interval, 1.07-1.72). CONCLUSION: In a large cohort of patients undergoing hemodialysis, a history of fragility fracture was an independent predictor of CV death.

Association between glycated albumin and sudden death in patients undergoing hemodialysis.

BACKGROUND: The frequency of sudden death and its risk factors in patients undergoing hemodialysis are unknown. This study was performed to examine the association between glycated albumin (GA) and sudden death in Japanese patients undergoing hemodialysis. METHODS: In total, 260 patients undergoing hemodialysis aged ≥18 years were retrospectively followed for a mean of 4.6 years. The patients' serum GA levels were divided into tertiles, and the patients' sex, age, albumin level, C-reactive protein (CRP) level, and cardiothoracic ratio (CTR) were selected as adjustment factors. A logistic regression model was used to calculate the odds ratio (OR) for the occurrence of sudden death by GA level. RESULTS: Ninety-one patients died during follow-up. Of the 91 deaths, 23 (25.2%) were defined as sudden deaths. Compared with non-sudden death cases, sudden death cases were significantly younger (p = 0.002) and had a higher proportion of men (p = 0.03), a higher proportion of diabetes (p = 0.008), and higher GA levels (p = 0.023). Compared with patients with the lowest GA levels (<15.2%), those with the highest GA levels (≥18.5%) had a sex- and age-adjusted OR for sudden death of 5.40 [95% confidence interval (CI): 1.35-21.85]. After adjusting for the albumin level, CRP level, and CTR in addition to sex and age, the OR for sudden death of patients with the highest GA levels increased to 6.80 (95%CI: 1.64-28.08); the relationship did not change. CONCLUSION: Serum GA levels were significantly associated with sudden death in patients undergoing hemodialysis.

Association of serum magnesium levels with renal prognosis in patients with chronic kidney disease.

BACKGROUND: Magnesium deficiency is associated with various health conditions, but its impact on the progression of chronic kidney disease (CKD) remains unclear. This study aimed to investigate the association between serum magnesium levels and prognosis of renal function in CKD patients. METHODS: This is an analysis of the Japan Chronic Kidney Disease Database Ex　(J-CKD-DB-Ex), which is a multicenter prospective cohort including CKD patients enrolled from January 1, 2014 to December 31, 2020. We included adult outpatients with CKD stage G3 and G4 at the time of initial magnesium measurement. Patients were classified by magnesium levels as low (<1.7 mg/dl), normal (1.7-2.6 mg/dl), or high (>2.6 mg/dl). The primary outcomes were the composite of an eGFR < 15 ml/min/1.73 m2 or a ≥30% reduction in eGFR from the initial measurement, which was defined as CKD progression. We applied the Kaplan-Meier analysis and Cox regression hazard model to examine the association between magnesium levels and CKD progression. RESULTS: The analysis included 9868 outpatients during the follow-up period. The low magnesium group was significantly more likely to reach CKD progression. Cox regression, adjusting for covariates and using the normal magnesium group as the reference, showed that the hazard ratio for the low magnesium group was 1.20 (1.08-1.34). High magnesium was not significantly associated with poor renal outcomes compared with normal magnesium. CONCLUSION: Based on large real-world data, this study demonstrated that low magnesium levels are associated with poorer renal outcomes.

Kidney outcomes associated with haematuria and proteinuria trajectories among patients with IgA nephropathy in real-world clinical practice: The Japan Chronic Kidney Disease Database.

AIM: Among patients with Immunoglobulin A (IgA) nephropathy, we aimed to identify trajectory patterns stratified by the magnitude of haematuria and proteinuria using repeated urine dipstick tests, and assess whether the trajectories were associated with kidney events. METHODS: Using a nationwide multicentre chronic kidney disease (CKD) registry, we analysed data from 889 patients with IgA nephropathy (mean age 49.3 years). The primary outcome was a sustained reduction in eGFR of 50% or more from the index date and thereafter. During follow-up (median 49.0 months), we identified four trajectories (low-stable, moderate-decreasing, moderate-stable, and high-stable) in both urine dipstick haematuria and proteinuria measurements, respectively. RESULTS: In haematuria trajectory analyses, compared to the low-stable group, the adjusted hazard ratios (HRs) (95% confidence interval [CI]) for kidney events were 2.59 (95% CI, 1.48-4.51) for the high-stable, 2.31 (95% CI, 1.19-4.50) for the moderate-stable, and 1.43 (95% CI, (0.72-2.82) for the moderate-decreasing groups, respectively. When each proteinuria trajectory group was subcategorized according to haematuria trajectories, the proteinuria group with high-stable and with modest-stable haematuria trajectories had approximately 2-times higher risk for eGFR reduction ≥50% compared to that with low-stable haematuria trajectory. CONCLUSION: Assessments of both haematuria and proteinuria trajectories using urine dipstick could identify high-risk IgA nephropathy patients.

Mechanisms of Tolerance Induction in Liver Transplantation: Lessons Learned from Fetomaternal Tolerance, Autoimmunity and Tumor Immunity.

Since the first published report of experimental kidney transplantation in dogs in 1902, there were many experimental and clinical trials of organ transplantation, with many sacrifices. After the establishment of the surgical technique and the discovery of immunosuppressive drugs, transplantation became the definitive treatment strategy for patients with terminal organ failure. However, this is not a common therapy method due to the difficulty of solving the fundamental issues behind organ transplantation, including the shortage of donor graft, potential risks of transplant surgery and economic capability. The pre- and post-transplant management of recipients is another critical issue that may affect transplant outcome. Most liver transplant recipients experience post-transplant complications, including infection, acute/chronic rejection, metabolic syndrome and the recurrence of hepatocellular carcinoma. Therefore, the early prediction and diagnosis of these complications may improve overall and disease-free survival. Furthermore, how to induce operational tolerance is the key to achieving the ultimate goal of transplantation. In this review, we focus on liver transplantation, which is known to achieve operational tolerance in some circumstances, and the mechanical similarities and differences between liver transplant immunology and fetomaternal tolerance, autoimmunity or tumor immunity are discussed.

Arginase 2 Promotes Cisplatin-Induced Acute Kidney Injury by the Inflammatory Response of Macrophages.

Acute kidney injury (AKI) is a complex clinical syndrome with a rapid decrease in renal function caused by several different etiologies, including sepsis, ischemia, and the administration of nephrotoxic drugs. Tubular arginase 2 (ARG2), an arginine-metabolic enzyme, is a potential therapeutic target for AKI, but it has not been confirmed under various AKI conditions. The aim of this study was to investigate ARG2 as a therapeutic target for cisplatin-induced AKI. Cisplatin-treated mice with a genetic deficiency in Arg2 had significant amelioration of renal dysfunction, characterized by decreased acute tubular damage and apoptosis. In contrast, cisplatin-induced tubular toxicity was not ameliorated in proximal tubule cells derived from Arg2-deficient mice. Immunohistochemical analysis demonstrated the increased infiltration of ARG2-positive macrophages in kidneys damaged by cisplatin. Importantly, cisplatin-treated Arg2 knockout mice exhibited a significant reduction in kidney inflammation, characterized by the decreased infiltration of inflammatory macrophages and reduced gene expression of interleukin (IL)-6 and IL-1ß. The secretion of IL-6 and IL-1ß induced by lipopolysaccharides was decreased in bone marrow-derived macrophages isolated from Arg2-deficient mice. Furthermore, the lipopolysaccharide-induced elevation of mitochondrial membrane potential and production of reactive oxygen species were reduced in bone marrow-derived macrophages lacking Arg2. These findings indicate that ARG2 promotes the inflammatory responses of macrophages through mitochondrial reactive oxygen species, resulting in the exacerbation of AKI. Therefore, targeting ARG2 in macrophages may constitute a promising therapeutic approach for AKI.

Acrolein produced during acute kidney injury promotes tubular cell death.

Acute kidney injury is an important global health concern as it is associated with high morbidity and mortality. Polyamines, essential for cell growth and proliferation, are known to inhibit cardiovascular disease. However, under conditions of cellular damage, toxic acrolein is produced from polyamines by the enzyme spermine oxidase (SMOX). We used a mouse renal ischemia-reperfusion model and human proximal tubule cells (HK-2) to investigate whether acrolein exacerbates acute kidney injury by renal tubular cell death. Acrolein visualized by acroleinRED was increased in ischemia-reperfusion kidneys, particularly in tubular cells. When HK-2 cells were cultured under 1% oxygen for 24 h, then switched to 21% oxygen for 24 h (hypoxia-reoxygenation), acrolein accumulated and SMOX mRNA and protein levels were increased. Acrolein induced cell death and fibrosis-related TGFB1 mRNA in HK-2 cells. Administration of the acrolein scavenger cysteamine suppressed the acrolein-induced upregulation of TGFB1 mRNA. Cysteamine also inhibited a decrease in the mitochondrial membrane potential observed by MitoTrackerCMXRos, and cell death induced by hypoxia-reoxygenation. The siRNA-mediated knockdown of SMOX also suppressed hypoxia-reoxygenation-induced acrolein accumulation and cell death. Our study suggests that acrolein exacerbates acute kidney injury by promoting tubular cell death during ischemia-reperfusion injury. Treatment to control the accumulation of acrolein might be an effective therapeutic option for renal ischemia-reperfusion injury.

Genome-wide association study of the risk of chronic kidney disease and kidney-related traits in the Japanese population: J-Kidney-Biobank.

Chronic kidney disease (CKD) is a syndrome characterized by a gradual loss of kidney function with decreased estimated glomerular filtration rate (eGFR), which may be accompanied by an increase in the urine albumin-to-creatinine ratio (UACR). Although trans-ethnic genome-wide association studies (GWASs) have been conducted for kidney-related traits, there have been few analyses in the Japanese population, especially for the UACR trait. In this study, we conducted a GWAS to identify loci related to multiple kidney-related traits in Japanese individuals. First, to detect loci associated with CKD, eGFR, and UACR, we performed separate GWASs with the following two datasets: 475 cases of CKD diagnosed at seven university hospitals and 3471 healthy subjects (dataset 1) and 3664 cases of CKD-suspected individuals with eGFR <60 ml/min/1.73 m2 or urinary protein ≥ 1+ and 5952 healthy subjects (dataset 2). Second, we performed a meta-analysis between these two datasets and detected the following associated loci: 10 loci for CKD, 9 loci for eGFR, and 22 loci for UACR. Among the loci detected, 22 have never been reported previously. Half of the significant loci for CKD were shared with those for eGFR, whereas most of the loci associated with UACR were different from those associated with CKD or eGFR. The GWAS of the Japanese population identified novel genetic components that were not previously detected. The results also suggest that the group primarily characterized by increased UACR possessed genetically different features from the group characterized by decreased eGFR.

Cumulative smoking dose is associated with subclinical renal injury: a pathological study in individuals without chronic kidney disease.

BACKGROUND: Epidemiological studies have identified smoking as an independent risk factor for development of chronic kidney disease. However, the early renal pathological lesions have not been clearly elucidated. METHODS: We investigated time-zero biopsy specimens from 547 living kidney donors and evaluated the relationships between smoking and renal histological changes, including arteriolar hyalinization, intimal thickening of small-medium arteries, global glomerulosclerosis, and interstitial fibrosis and tubular atrophy (IF/TA). RESULTS: A total of 199 subjects (36.4%) had smoking history; 92 (16.8%) and 107 (19.6%) subjects had <20 pack-years and ≥20 pack-years of smoking, respectively. Cumulative smoking dose was significantly associated with prevalence of arteriolar hyalinization: the multivariable-adjusted odds ratio (OR) per 20 pack-year increase was 1.50 (95% confidence interval 1.15-1.97). The ORs for smokers with <20 pack-years and ≥20 pack-years versus never-smokers were 1.76 (1.01-3.09) and 2.56 (1.48-4.44), respectively. Smoking was also associated with prevalence of >10% global glomerulosclerosis: the OR per 20 pack-year increase was 1.24 (0.96-1.59). The ORs for smokers with <20 pack-years and ≥20 pack-years versus never-smokers were 1.50 (0.98-2.78) and 2.11 (1.18-3.79), respectively. The ORs for these pathological changes increased significantly depending on cumulative smoking dose. Intimal thickening of small-medium arteries and IF/TA were not associated with smoking status. The prevalence of arteriolar hyalinization remained higher in patients with ≥10 years since smoking cessation than in never-smokers [OR 2.23 (1.03-4.83)]. CONCLUSIONS: Subclinical pathological injury caused by smoking is potentially associated with renal arteriolar hyalinization and glomerular ischaemia.

Determinants of the effectiveness of bezafibrate combined with ursodeoxycholic acid in patients with primary biliary cholangitis.

BACKGROUND AND AIMS: For patients with primary biliary cholangitis (PBC) exhibiting suboptimal responses to ursodeoxycholic acid (UDCA), obeticholic acid (OCA), and bezafibrate (BZF) are currently used and shown to improve long-term outcomes. Nevertheless, we encounter patients who die or undergo liver transplantation (LT) even with combination treatment. In this study, we explored prognostic indicators in patients receiving combination treatment of UDCA and BZF. METHODS: We took advantage of the Japanese PBC registry and enrolled patients who received both UDCA and BZF therapy in 2000 or later. The covariates investigated included baseline covariates as well as treatment covariates. Two main outcomes (all-cause death or LT and liver-related death or LT) were assessed using multivariable-adjusted Cox proportional hazards models. RESULTS: In total, 772 patients were included. The median follow-up was 7.1 years. Using the Cox regression model, bilirubin (hazard ratio [HR] 6.85, 95% confidence interval [CI] 1.73-27.1, p = 0.006), alkaline phosphatase (HR 5.46, 95% CI 1.32-22.6, p = 0.019), and histological stage (HR 4.87, 95% CI 1.16-20.5, p = 0.031) were found associated with LT-free survival. For survival free from liver disease-related death or LT, albumin (HR 7.72, 95% CI 1.48-40.4, p = 0.016) and bilirubin (HR 14.5, 95% CI 2.37-88.5, p = 0.004) were found significantly associated. CONCLUSION: In patients with PBC receiving combination therapy, prognostic variables were similar to those in patients receiving UDCA monotherapy. These results indicate the importance of diagnosing patients with PBC at an earlier stage because of the reduced effectiveness of BZF at advanced stages.

Association between microscopic hematuria and albuminuria in patients with chronic kidney disease caused by diabetes and hypertension: the Fukuoka Kidney disease Registry Study.

BACKGROUND: The association between microscopic hematuria (MH) and albuminuria in patients with chronic kidney disease (CKD) caused by diabetes and hypertension remains unclear. METHODS: The Fukuoka Kidney disease Registry Study is a Japanese multicenter prospective cohort study of 4476 patients with non-dialysis-dependent CKD. In this cohort, we conducted a cross-sectional study in 994 patients with diabetic nephropathy and hypertensive nephrosclerosis. Patients were divided into three groups according to erythrocyte count in urine sediment [T1: < 5/high power field (HPF); T2: 5-9/HPF; T3: ≥ 10/HPF]. Macroalbuminuria was defined as urinary albumin-creatinine ratio > 300 mg/g. Associations between the degree of MH (T1-T3) and the prevalence of macroalbuminuria were analyzed using logistic regression. RESULTS: The prevalence of macroalbuminuria was 50.8%, 50.4%, and 67.4% in T1 (n = 725), T2 (n = 226), and T3 (n = 43), respectively. The multivariable-adjusted odds ratios for the presence of macroalbuminuria were 0.95 [95% confidence interval (CI) 0.65-1.39; P = 0.86] and 2.50 (95% CI 1.15-5.47; P = 0.022) for patients in T2 and T3, respectively, compared with patients in T1. CONCLUSIONS: MH with erythrocytes ≥ 10/HPF was significantly associated with increased prevalence of macroalbuminuria in patients with non-dialysis-dependent CKD caused by diabetes and hypertension.

Association between hyporesponsiveness to erythropoiesis-stimulating agents and risk of brain hemorrhage in patients undergoing hemodialysis: the Q-Cohort Study.

BACKGROUND: Hyporesponsiveness to erythropoiesis-stimulating agents (ESAs) is associated with increased risks of all cause and cardiovascular mortality in patients undergoing hemodialysis (HD). However, the impact of the hematopoietic response to ESAs on the development of stroke, including brain hemorrhage and infarction, remains unclear. METHODS: In total, 2886 patients undergoing maintenance HD registered in the Q-Cohort Study who were treated with ESAs were prospectively followed up for 4 years. The hematopoietic response to ESAs was evaluated by the erythropoietin resistance index (ERI), calculated by dividing the weekly dose of ESA by post-HD weight and hemoglobin (U/kg/week/g/dL). The primary outcomes were the incidences of brain hemorrhage and infarction. Patients were divided into quartiles based on their ERI at baseline (Q1, ≤ 4.1; Q2, 4.2-7.0; Q3, 7.1-11.2; and Q4, ≥ 11.3). The risks of brain hemorrhage and infarction were estimated using Cox proportional hazards models, adjusting for potential confounders. RESULTS: During the 4 year follow-up period, 71 patients developed brain hemorrhage and 116 developed brain infarction. In the multivariable analysis, the incidence of brain hemorrhage in the highest quartile (Q4) was significantly higher than that in the lowest quartile (Q1) (hazard ratio [95% confidence interval], 2.18 [1.08-4.42]). However, the association between the ERI and the incidence of brain infarction was not significant. CONCLUSIONS: A higher ERI was associated with an increased risk of brain hemorrhage, but not brain infarction, in patients undergoing maintenance HD. A high ERI is thus an important risk factor for brain hemorrhage in these patients.

Prevalence of hyponatremia and associated factors in patients with chronic kidney disease: the Fukuoka Kidney Disease Registry (FKR) study.

BACKGROUND: Hyponatremia is a common and important electrolyte disorder. However, the prevalence and factors associated with hyponatremia in patients with chronic kidney disease (CKD) are unknown. METHODS: We studied the factors associated with hyponatremia (< 135 mEq/L) in CKD patients registered in the Fukuoka Kidney Disease Registry (FKR) study using a logistic regression model variable selected using the variable reduction method. RESULTS: We analyzed the baseline characteristics of 4367 participants with CKD (age, 64 ± 16 years; male, 56.1%). Hyponatremia was detected in 2.0% of the patients at baseline, and multivariate logistic analysis showed that the independent factors for hyponatremia were body mass index (odds ratio [OR] 0.91; 95% confidence interval [CI] 0.85-0.97), prescription of benzodiazepine (OR 2.31; 95% CI 1.39-3.86), blood hemoglobin level (OR 0.76; 95% CI 0.65-0.88), and serum C-reactive protein level (OR 1.27; 95% CI 1.04-1.54). CONCLUSION: The cross-sectional analysis using baseline data from the FKR study revealed independent factors associated with hyponatremia in patients with decreased kidney function. Longitudinal analyses of the FKR cohort are needed to evaluate the effects of these factors on the prognosis of hyponatremia in patients with CKD.

Angiotensin II receptor blockers and bone fracture in chronic kidney disease patients: the Fukuoka kidney disease Registry Study.

BACKGROUND: Angiotensin II receptor blockers (ARBs) reportedly reduce the risk of developing bone fractures; however, this association remains unclear among patients with chronic kidney disease (CKD). METHODS: This was a cross-sectional study of 3380 CKD patients enrolled in the Fukuoka Kidney disease Registry Study, a multicenter prospective observational cohort study of non-dialysis-dependent CKD patients. The patients were divided into two groups, those taking ARBs and those who were not. Logistic regression models were used to examine the association between ARBs and bone fracture. RESULTS: Approximately 67.0% of the participants were on ARBs, and 6.3% had a history of bone fracture. The history of bone fracture was significantly lower in patients with prescribed ARB and remained significant even after multivariable adjustment (odds ratio, 0.68; 95% confidence interval, 0.51-0.93). Other antihypertensive drugs, such as thiazide diuretics, which were reportedly helpful in preventing fractures, did not alter the bone fracture history and did not change among ARB users and non-users. CONCLUSIONS: The present study showed that administering ARB was significantly associated with a lower frequency of bone fracture history.

Sex differences in the association between urate metabolism and kidney outcomes in patients with chronic kidney disease.

BACKGROUND: The association between serum uric acid (SUA) concentration and kidney outcomes in patients with chronic kidney disease (CKD) is controversial. Furthermore, there are no reports regarding the association of clearance of uric acid (CUA) with kidney outcomes. We aimed to determine whether SUA or CUA was associated with kidney outcomes in patients with CKD stratified by sex. METHODS: The present prospective study was conducted in 815 patients (523 men and 292 women) with CKD. The participants were divided into quartiles (Q1-Q4) of SUA or CUA for each sex. Endpoints were defined as a composite of doubling of serum creatinine (SCr), end-stage kidney disease (ESKD), or death (outcome 1) and a composite of doubling of SCr or ESKD (outcome 2). RESULTS: During a median follow-up of 2.5 years, outcomes 1 and 2 occurred in 363 and 321 patients, respectively. Multivariable-adjusted Cox analyses showed that in men, the hazard ratios (95% confidence intervals) for outcome 1 of Q1, Q2, and Q3 of CUA were 2.08 (1.18-3.70), 2.03 (1.22-3.39), and 1.85 (1.17-2.95), respectively, compared with Q4. Additionally, there were similar associations between lower CUA quartiles and outcome 2 in men. However, no associations between SUA and either outcome were observed in men. Conversely, in women, neither SUA nor CUA was associated with an outcome. CONCLUSION: In CKD, lower CUA was independently associated with poor kidney outcomes only in men, and in both sexes, there was no association of SUA with kidney outcomes.