Search

Abstract Background Although roxadustat has been reported to cause central hypothyroidism, the details of the mechanisms and clinical characteristics of patients who are prone to developing hypothyroidism with roxadustat are uncertain. Case presentation A 53-year-old man with a 3-year history of hemodialysis due to diabetic kidney disease who had been treated with roxadustat, a hypoxia-inducible factor prolyl hydroxylase inhibitor, for 2 years was admitted to the hospital because of worsening gait disturbance and impaired consciousness. He had also acquired pure red cell aplasia associated with T-cell large granular lymphocytic leukemia and received multiple blood transfusions. Because his serum concentration of thyroid hormones was low, we diagnosed him with hypothyroidism, and his consciousness level recovered to normal with thyroid hormone replacement therapy. Computed tomography revealed a high-intensity atrophic thyroid gland, and magnetic resonance imaging showed diffusely reduced T2 and T1 signals of the pituitary anterior gland. These findings confirmed the accumulation of iron in the pituitary and thyroid glands. Combined pituitary stimulation tests with thyrotropin-releasing hormone, luteinizing hormone-releasing hormone, and corticotropin-releasing hormone revealed that the patient had pan-hypopituitarism. After discontinuation of roxadustat, the patient was treated with another hypoxia-inducible factor prolyl hydroxylase inhibitor, vadadustat. One month after switching medication, a stimulation test with thyrotropin-releasing hormone showed normal responses to thyroid-stimulating hormone. The patient was treated with levothyroxine 50 μg daily without any significant symptoms and is currently under follow-up observation as an outpatient. Conclusions We encountered a dialysis patient with roxadustat-induced hypothyroidism associated with transfusion iron overload. To our knowledge, this is the first case to clearly show that roxadustat can impair thyroid-stimulating hormone secretion in repeated thyrotropin-releasing hormone stimulation tests. Because the present patient had received roxadustat for more than 2 years before hypothyroidism became apparent, regular monitoring of the thyroid function may be needed in patients with renal anemia who have been treated with roxadustat, especially those at high risk of thyroid dysfunction.

Abstract Aims/Introduction We evaluated the efficacy of multifactorial intensive treatment (IT) on renal outcomes in patients with type 2 diabetes and advanced‐stage diabetic kidney disease (DKD). Materials and Methods The Diabetic Nephropathy Remission and Regression Team Trial in Japan (DNETT‐Japan) is a multicenter, open‐label, randomized controlled trial with a 5‐year follow‐up period. We randomly assigned 164 patients with advanced‐stage diabetic kidney disease (urinary albumin‐to‐creatinine ratio ≥300 mg/g creatinine, serum creatinine level 1.2–2.5 mg/dL in men and 1.0–2.5 mg/dL in women) to receive either IT or conventional treatment. The primary composite outcome was end‐stage kidney failure, doubling of serum creatinine or death from any cause, which was assessed in the intention‐to‐treat population. Results The IT tended to reduce the risk of primary end‐points as compared with conventional treatment, but the difference between treatment groups did not reach the statistically significant level (hazard ratio 0.69, 95% confidence interval 0.43–1.11; P = 0.13). Meanwhile, the decrease in serum low‐density lipoprotein cholesterol level and the use of statin were significantly associated with the decrease in primary outcome (hazard ratio 1.14; 95% confidence interval 1.05–1.23, P

Abstract Background Pleuroperitoneal leak is an uncommon but significant complication of peritoneal dialysis. Although the exact pathogenesis of pleuroperitoneal communication remains unclear, the pressure gradient between the thorax and abdominal cavity has been thought to play a major role. Case presentation A 48-year-old man with diabetes mellitus and hypertension who had been treated with continuous ambulatory peritoneal dialysis (1.5 L dwells four times a day) for 3 months was admitted because of massive right-sided pleural effusion. He underwent video-assisted thoracoscopic surgery for blebs on the diaphragm. Six weeks after diaphragmatic repair, he resumed peritoneal dialysis (1.5 L dwells four times a day) with once-a-week hemodialysis. Thereafter, pleural effusion was not significant on a chest radiogram. Six months after surgery, his dwell volume increased from 1500 to 2000 ml, and significant right-sided pleural effusion also developed. Conclusion Pleuroperitoneal leak caused by blebs can recur even after surgical treatment, and reducing the dwell volume may be effective for patients with pleuroperitoneal communication.

Glucose-stimulated insulin secretion (GSIS) by pancreatic β cells is biphasic. However, the physiological significance of biphasic GSIS and its relationship to diabetes are not yet fully understood. This study demonstrated that impaired first-phase GSIS follows fasting, leading to increased blood glucose levels and brain glucose distribution in humans. Animal experiments to determine a possible network between the brain and β cells revealed that fasting-dependent hyperactivation of AMP-activated protein kinase in the hypothalamus inhibited first-phase GSIS by stimulating the α-adrenergic pancreatic nerve. Furthermore, abnormal excitability of this brain-β cell neural axis was involved in diabetes-related impairment of first-phase GSIS in diabetic animals. Finally, pancreatic denervation improved first-phase GSIS and glucose tolerance and ameliorated severe diabetes by preventing β cell loss in diabetic animals. These results indicate that impaired first-phase GSIS is critical for brain distribution of dietary glucose after fasting. Furthermore, β cells in individuals with diabetes mistakenly sense that they are under conditions that mimic prolonged fasting. The present study provides additional insight into both β cell physiology and the pathogenesis of β cell dysfunction in type 2 diabetes.

In patients with diabetes, albuminuria is a risk marker of end-stage renal disease and cardiovascular events. An increased renin-angiotensin system activity has been reported to play an important role in the pathological processes in these conditions. We compared the effect of aliskiren, a direct renin inhibitor (DRI), with that of angiotensin receptor blockers (ARBs) on albuminuria and urinary excretion of angiotensinogen, a marker of intrarenal renin-angiotensin system activity.We randomly assigned 237 type 2 diabetic patients with high-normal albuminuria (10 to

Prevention of cardiovascular disease (CVD) is an important therapeutic object of diabetes care. This study assessed whether an index based on plasma free amino acid (PFAA) profiles could predict the onset of CVD in diabetic patients. The baseline concentrations of 31 PFAAs were measured with high-performance liquid chromatography-electrospray ionization-mass spectrometry in 385 Japanese patients with type 2 diabetes registered in 2001 for our prospective observational follow-up study. During 10 years of follow-up, 63 patients developed cardiovascular composite endpoints (myocardial infarction, angina pectoris, worsening of heart failure and stroke). Using the PFAA profiles and clinical information, an index (CVD-AI) consisting of six amino acids to predict the onset of any endpoints was retrospectively constructed. CVD-AI levels were significantly higher in patients who did than did not develop CVD. The area under the receiver-operator characteristic curve of CVD-AI (0.72 [95% confidence interval (CI): 0.64-0.79]) showed equal or slightly better discriminatory capacity than urinary albumin excretion rate (0.69 [95% CI: 0.62-0.77]) on predicting endpoints. A multivariate Cox proportional hazards regression analysis showed that the high level of CVD-AI was identified as an independent risk factor for CVD (adjusted hazard ratio: 2.86 [95% CI: 1.57-5.19]). This predictive effect of CVD-AI was observed even in patients with normoalbuminuria, as well as those with albuminuria. In conclusion, these results suggest that CVD-AI based on PFAA profiles is useful for identifying diabetic patients at risk for CVD regardless of the degree of albuminuria, or for improving the discriminative capability by combining it with albuminuria.

Diabetic nephropathy is a leading cause of end-stage renal disease worldwide. The multipronged drug approach targeting blood pressure and serum levels of glucose, insulin, and lipids fails to fully prevent the onset and progression of diabetic nephropathy. Therefore, a new therapeutic target to combat diabetic nephropathy is required. Autophagy is a catabolic process that degrades damaged proteins and organelles in mammalian cells and plays a critical role in maintaining cellular homeostasis. The accumulation of proteins and organelles damaged by hyperglycemia and other diabetes-related metabolic changes is highly associated with the development of diabetic nephropathy. Recent studies have suggested that autophagy activity is altered in both podocytes and proximal tubular cells under diabetic conditions. Autophagy activity is regulated by both nutrient state and intracellular stresses. Under diabetic conditions, an altered nutritional state due to nutrient excess may interfere with the autophagic response stimulated by intracellular stresses, leading to exacerbation of organelle dysfunction and diabetic nephropathy. In this review, we discuss new findings showing the relationships between autophagy and diabetic nephropathy and suggest the therapeutic potential of autophagy in diabetic nephropathy.

BACKGROUND: Several linkage analyses have mapped a susceptibility locus for diabetic nephropathy to chromosome 18q22-23, and polymorphisms within the carnosine dipeptidase 1 gene (CNDP1), located on 18q22.3, have been shown to be associated with diabetic nephropathy in European subjects with type 2 diabetes. However, the association of this locus with diabetic nephropathy has not been evaluated in the Japanese population. In this study, we examined the association of polymorphisms within the CNDP1/CNDP 2 locus with diabetic nephropathy in Japanese subjects with type 2 diabetes. METHODOLOGY/PRINCIPAL FINDINGS: We genotyped a leucine repeat polymorphism (D18S880) that is within CNDP1 along with 29 single nucleotide polymorphisms (SNPs) in the CNDP1/CNDP2 locus for 2,740 Japanese subjects with type 2 diabetes (1,205 nephropathy cases with overt nephropathy or with end-stage renal disease [ESRD], and 1,535 controls with normoalbuminuria). The association of each polymorphism with diabetic nephropathy was analysed by performing logistic regression analysis. We did not observe any association between D18S880 and diabetic nephropathy in Japanese subjects with type 2 diabetes. None of the 29 SNPs within the CNDP1/CNDP2 locus were associated with diabetic nephropathy, but a subsequent sex-stratified analysis revealed that 1 SNP in CNDP1 was nominally associated with diabetic nephropathy in women (rs12604675-A; p = 0.005, odds ratio [OR] = 1.76, 95% confidence interval [CI], 1.19-2.61). Rs12604675 was associated with overt proteinuria (p = 0.002, OR = 2.18, 95% CI, 1.32-3.60), but not with ESRD in Japanese women with type 2 diabetes. CONCLUSIONS/SIGNIFICANCE: Rs12604675-A in CNDP1 may confer susceptibility to overt proteinuria in Japanese women with type 2 diabetes.

Acetyl coenzyme A carboxylase B gene (ACACB) single nucleotide polymorphism (SNP) rs2268388 is reproducibly associated with type 2 diabetes (T2DM)-associated nephropathy (DN). ACACB knock-out mice are also protected from obesity. This study assessed relationships between rs2268388, body mass index (BMI) and gene expression in multiple populations, with and without T2DM. Among subjects without T2DM, rs2268388 DN risk allele (T) associated with higher BMI in Pima Indian children (n = 2021; p-additive = 0.029) and African Americans (AAs) (n = 177; p-additive = 0.05), with a trend in European Americans (EAs) (n = 512; p-additive = 0.09), but not Germans (n = 858; p-additive = 0.765). Association with BMI was seen in a meta-analysis including all non-T2DM subjects (n = 3568; p-additive = 0.02). Among subjects with T2DM, rs2268388 was not associated with BMI in Japanese (n = 2912) or EAs (n = 1149); however, the T allele associated with higher BMI in the subset with BMI≥30 kg/m(2) (n = 568 EAs; p-additive = 0.049, n = 196 Japanese; p-additive = 0.049). Association with BMI was strengthened in a T2DM meta-analysis that included an additional 756 AAs (p-additive = 0.080) and 48 Hong Kong Chinese (p-additive = 0.81) with BMI≥30 kg/m(2) (n = 1575; p-additive = 0.0033). The effect of rs2268388 on gene expression revealed that the T risk allele associated with higher ACACB messenger levels in adipose tissue (41 EAs and 20 AAs with BMI>30 kg/m(2); p-additive = 0.018) and ACACB protein levels in the liver tissue (mixed model p-additive = 0.03, in 25 EA bariatric surgery patients with BMI>30 kg/m(2) for 75 exams). The T allele also associated with higher hepatic triglyceride levels. These data support a role for ACACB in obesity and potential roles for altered lipid metabolism in susceptibility to DN.

Recent studies have proposed that n-3 polyunsaturated fatty acids (n-3 PUFAs) have direct antioxidant and anti-inflammatory effects in vascular tissue, explaining their cardioprotective effects. However, the molecular mechanisms are not yet fully understood. We tested whether n-3 PUFAs showed antioxidant activity through the activation of nuclear factor erythroid 2-related factor 2 (Nrf2), a master transcriptional factor for antioxidant genes. C57BL/6 or Nrf2(-/-) mice were fed a fish-oil diet for 3 weeks. Fish-oil diet significantly increased the expression of heme oxygenase-1 (HO-1), and endothelium-dependent vasodilation in the aorta of C57BL/6 mice, but not in the Nrf2(-/-) mice. Furthermore, we observed that 4-hydroxy hexenal (4-HHE), an end-product of n-3 PUFA peroxidation, was significantly increased in the aorta of C57BL/6 mice, accompanied by intra-aortic predominant increase in docosahexaenoic acid (DHA) rather than that in eicosapentaenoic acid (EPA). Human umbilical vein endothelial cells were incubated with DHA or EPA. We found that DHA, but not EPA, markedly increased intracellular 4-HHE, and nuclear expression and DNA binding of Nrf2. Both DHA and 4-HHE also increased the expressions of Nrf2 target genes including HO-1, and the siRNA of Nrf2 abolished these effects. Furthermore, DHA prevented oxidant-induced cellular damage or reactive oxygen species production, and these effects were disappeared by an HO-1 inhibitor or the siRNA of Nrf2. Thus, we found protective effects of DHA through Nrf2 activation in vascular tissue, accompanied by intra-vascular increases in 4-HHE, which may explain the mechanism of the cardioprotective effects of DHA.

Saturated fatty acid (SFA)-related lipotoxicity is a pathogenesis of diabetes-related renal proximal tubular epithelial cell (PTEC) damage, closely associated with a progressive decline in renal function. This study was designed to identify a free fatty acid (FFA) metabolism-related enzyme that can protect PTECs from SFA-related lipotoxicity. Among several enzymes involved in FFA metabolism, we identified stearoyl-CoA desaturase-1 (SCD1), whose expression level significantly decreased in the kidneys of high-fat diet (HFD)-induced diabetic mice, compared with non-diabetic mice. SCD1 is an enzyme that desaturates SFAs, converting them to monounsaturated fatty acids (MUFAs), leading to the formation of neutral lipid droplets. In culture, retrovirus-mediated overexpression of SCD1 or MUFA treatment significantly ameliorated SFA-induced apoptosis in PTECs by enhancing intracellular lipid droplet formation. In contrast, siRNA against SCD1 exacerbated the apoptosis. Both overexpression of SCD1 and MUFA treatment reduced SFA-induced apoptosis via reducing endoplasmic reticulum stress in cultured PTECs. Thus, HFD-induced decrease in renal SCD1 expression may play a pathogenic role in lipotoxicity-induced renal injury, and enhancing SCD1-mediated desaturation of SFA and subsequent formation of neutral lipid droplets may become a promising therapeutic target to reduce SFA-induced lipotoxicity. The present study provides a novel insight into lipotoxicity in the pathogenesis of diabetic nephropathy.

A 21-year-old Japanese male with severe hemophilia A was developed end-stage renal failure. He was placed on combination therapy with peritoneal dialysis (PD) and hemodialysis (HD). Eight months later, he developed a hypertensive cerebral hemorrhage. After emergency surgery, he was managed with PD without HD to avoid cerebral edema. One month later, his renal replacement therapy was switched to HD (three times a week) from PD, since a ventriculoperitoneal shunt catheter was placed to treat his hydrocephalus. HD could be performed safety without anticoagulant agents on condition that factor VIII is given after every HD.

Peroxisome proliferator-activated receptors (PPARs) are a nuclear receptor family of ligand-inducible transcription factors, which have three different isoforms: PPARα, δ and γ. It has been demonstrated that PPARα and γ agonists have renoprotective effects in proteinuric kidney diseases; however, the role of PPARδ agonists in kidney diseases remains unclear. Thus, we examined the renoprotective effect of GW501516, a PPARδ agonist, in a protein-overload mouse nephropathy model and identified its molecular mechanism. Mice fed with a control diet or GW501516-containing diet were intraperitoneally injected with free fatty acid (FFA)-bound albumin or PBS(-). In the control group, protein overload caused tubular damages, macrophage infiltration and increased mRNA expression of MCP-1 and TNFα. These effects were prevented by GW501516 treatment. In proteinuric kidney diseases, excess exposure of proximal tubular cells to albumin, FFA bound to albumin or cytokines such as TNFα is detrimental. In vitro studies using cultured proximal tubular cells showed that GW501516 attenuated both TNFα- and FFA (palmitate)-induced, but not albumin-induced, MCP-1 expression via direct inhibition of the TGF-β activated kinase 1 (TAK1)-NFκB pathway, a common downstream signaling pathway to TNFα receptor and toll-like receptor-4. In conclusion, we demonstrate that GW501516 has an anti-inflammatory effect in renal tubular cells and may serve as a therapeutic candidate to attenuate tubulointerstitial lesions in proteinuric kidney diseases.

Diabetic nephropathy is a leading cause of end-stage renal disease, which is increasing in incidence worldwide, despite intensive treatment approaches such as glycemic and blood pressure control in patients with diabetes mellitus. New therapeutic strategies are needed to prevent the onset of diabetic nephropathy. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated nuclear transcription factors that play important roles in lipid and glucose homeostases. These agents might prevent the progression of diabetic nephropathy, since PPAR agonists improve dyslipidemia and insulin resistance. Furthermore, data from murine models suggest that PPAR agonists also have independent renoprotective effects by suppressing inflammation, oxidative stress, lipotoxicity, and activation of the renin-angiotensin system. This review summarizes data from clinical and experimental studies regarding the relationship between PPARs and diabetic nephropathy. The therapeutic potential of PPAR agonists in the treatment of diabetic nephropathy is also discussed.

A 31-year-old woman with retinitis pigmentosa who had been diagnosed with renal failure due to nephrosclerosis related to hypertensive disorders of pregnancy was referred to our hospital to prepare for renal replacement therapy. Ultrasonography and MRI of the kidneys revealed multiple corticomedullary cysts. A renal biopsy showed that the tubules were tortuous and atrophic with segmented tubular basement membrane thickening. These findings indicated that she had Senior-Løken syndrome. A molecular genetic analysis was performed, and homozygous deletion of the gene encoding nephronophthisis-1 was found. Thus, the clinical diagnosis of Senior- Løken syndrome was genetically confirmed. Because her renal function was gradually worsening, she was scheduled to undergo living donor kidney transplantation. Senior- Løken syndrome, which is recognised as a very rare paediatric inherited disease characterised by nephronophthisis and eye problems, can cause adult- onset end- stage renal failure. [ABSTRACT FROM AUTHOR]

Background. O-linked β-N-acetylglucosamine modification (O-GlcNAcylation) is a post-translational modification of intracellular proteins, serving as a nutrient sensor. Growing evidence has demonstrated its physiological and pathological importance in various mammalian tissues. This study examined the physiological role of O-GlcNAcylation in podocyte function and development. Methods. O-GlcNAc transferase (Ogt) is a critical enzyme for O-GlcNAcylation and resides on the X chromosome. To abrogate O-GlcNAcylation in podocytes, we generated congenital and tamoxifen (TM)-inducible podocyte-specific Ogt knockout mice (Podo-Ogty/y/- and TM-Podo-Ogty/y/-, respectively) and analyzed their renal phenotypes. Results. Podo-Ogty/y/- mice showed normal podocyte morphology at birth. However, they developed albuminuria at 8 weeks of age, increasing progressively until age 32 weeks. Glomerular sclerosis, proteinuria-related tubulointerstitial lesions and markedly altered podocyte foot processes, with decreased podocin expression, were observed histologically in 32-week-old Podo-Ogty/y/- mice. Next, we induced adult-onset deletion of the Ogt gene in podocytes by TM injection in 8-week-old TM-Podo-Ogty/y/- mice. In contrast to Podo-Ogty/y/- mice, the induced TM-Podo-Ogty/y/- mice did not develop albuminuria or podocyte damage, suggesting a need for O-GlcNAcylation to form mature foot processes after birth. To test this possibility, 3-week-old Podo-Ogty/y/- mice were treated with Bis-T-23, which stimulates actin-dependent dynamin oligomerization, actin polymerization and subsequent foot process elongation in podocytes. Albuminuria and podocyte damage in 16-week-old Podo-Ogty/y/- mice were prevented by Bis-T-23 treatment. Conclusions. O-GlcNAcylation is necessary for maturation of podocyte foot processes, particularly after birth. Our study provided new insights into podocyte biology and OGlcNAcylation. [ABSTRACT FROM AUTHOR]

Anticoagulants have recently been recognised as a cause of acute kidney injury (AKI). We describe the case of a 75-year-old man with IgA vasculitis and atrial fibrillation treated with rivaroxaban, who presented with macroscopic haematuria and an acute decline in renal function. Two months before referral, he noted palpable purpuric lesions and was diagnosed with IgA vasculitis based on skin biopsy findings; the skin lesion disappeared following treatment with a steroid external preparation. Renal biopsy revealed glomerular haemorrhage and red blood cell casts. Although rivaroxaban was withdrawn, his kidney function worsened and he was started on haemodialysis. His renal function did not recover. To the best of our knowledge, this is the first case of direct oral anticoagulant (DOAC)- related AKI in systemic vasculitis. During DOAC therapy, close monitoring of a patient’s urinalysis results and their renal function may be required for patients with systemic vasculitis to avoid AKI. [ABSTRACT FROM AUTHOR]

Overcoming refractory massive proteinuria remains a clinical and research issue in diabetic nephropathy. This study was designed to investigate the pathogenesis of massive proteinuria in diabetic nephropathy, with a special focus on podocyte autophagy, a system of intracellular degradation that maintains cell and organelle homeostasis, using human tissue samples and animal models. Insufficient podocyte autophagy was observed histologically in patients and rats with diabetes and massive proteinuria accompanied by podocyte loss, but not in those with no or minimal proteinuria. Podocyte-specific autophagy-deficient mice developed podocyte loss and massive proteinuria in a high-fat diet (HFD)-induced diabetic model for inducing minimal proteinuria. Interestingly, huge damaged lysosomes were found in the podocytes of diabetic rats with massive proteinuria and HFD-fed, podocyte-specific autophagy-deficient mice. Furthermore, stimulation of cultured podocytes with sera from patients and rats with diabetes and massive proteinuria impaired autophagy, resulting in lysosome dysfunction and apoptosis. These results suggest that autophagy plays a pivotal role in maintaining lysosome homeostasis in podocytes under diabetic conditions, and that its impairment is involved in the pathogenesis of podocyte loss, leading to massive proteinuria in diabetic nephropathy. These results may contribute to the development of a new therapeutic strategy for advanced diabetic nephropathy. [ABSTRACT FROM AUTHOR]

Diabetic nephropathy is the leading cause of end-stage renal disease worldwide. The multipronged drug approach still fails to fully prevent the onset and progression of diabetic nephropathy. Therefore, a new therapeutic target to improve the prognosis of diabetic nephropathy is urgently required. Nutrient-sensing signals and their related intracellular machinery have evolved to combat prolonged periods of starvation in mammals; and these systems are conserved in the kidney. Recent studies have suggested that the activity of three nutrient-sensing signals, mTORC1, AMPK, and Sirt1, is altered in the diabetic kidney. Furthermore, autophagy activity, which is regulated by the above-mentioned nutrient-sensing signals, is also altered in both podocytes and proximal tubular cells under diabetic conditions. Under diabetic conditions, an altered nutritional state owing to nutrient excess may disturb cellular homeostasis regulated by nutrient-responsible systems, leading to exacerbation of organelle dysfunction and diabetic nephropathy. In this review, we discuss new findings showing relationships between nutrient-sensing signals, autophagy, and diabetic nephropathy and suggest the therapeutic potential of nutrient-sensing signals in diabetic nephropathy. [ABSTRACT FROM AUTHOR]