Association of Circulatory Iron Deficiency With an Enlarged Heart in Patients With End-Stage Kidney Disease.

OBJECTIVES: High prevalence of iron deficiency (ID) and cardiomyopathy have been observed in patients with end-stage kidney disease (ESKD). Our objective was to clarify associations between ID and cardiac remodeling in patients with ESKD. DESIGN AND METHODS: A cross-sectional study was conducted using 1974 Japanese patients with ESKD at the initiation of maintenance dialysis. Levels of hemoglobin (Hb), iron status, and cardiac enlargement as assessed by the cardiothoracic ratio (CTR) were determined immediately before the first hemodialysis session. Circulatory ID was defined as transferrin saturation (TSAT) < 20%, and stored ID was defined as ferritin level <100 ng/dL. RESULTS: The mean age was 67 years. Median CTR was 54.0%. The prevalence of circulatory and stored ID was found to be 38% and 34%, respectively. CTR was higher in patients with circulatory ID than in those without. Even in ESKD patients without overhydration, significant negative association was observed between TSAT and CTR. Higher odds ratios in parallel with higher CTR categories compared with the reference category of CTR <45% were found in patients with TSAT <20% on multinomial analysis, but ferritin did not show any significant associations. The odds ratio for CTR >54% showed an upward trend in patients with TSAT <20% (odds ratio: 1.3) and <10% (odds ratio: 1.6) compared with the reference, even after adjusting for confounding variables such as Hb and ferritin. However, that phenomenon was eliminated by adding usage of an iron agent. CONCLUSIONS: Circulatory ID is closely associated with an enlarged heart independent of ferritin and Hb. Iron supplementation in the predialysis phase of chronic kidney disease may prevent cardiac remodeling independent of Hb level in patients chronic kidney disease.

Possible prevention of uremic nausea by vitamin D receptor activators in non-dialysis patients with stage 5 chronic kidney disease.

BACKGROUND: Nausea is a major uremic symptom and a frequent indication for starting dialysis. However, preventive medication for uremic nausea has not yet been identified. Vitamin D receptor activators (VDRAs) may prevent uremic nausea via their pleiotropic actions. The objective of this study was to explore whether VDRA administration during the predialysis period is associated with a reduced prevalence of uremic nausea just prior to beginning dialysis. METHODS: A multicenter, retrospective, cross-sectional study was performed to identify a medication to prevent uremic nausea. Patients with stage 5 CKD who were followed-up over 3 months were included. The primary outcomes examined were the prevalence of uremic nausea, congestive heart failure (CHF), and intractable edema at dialysis commencement. The predictor variable was VDRA use during the predialysis period. RESULTS: One thousand five hundred and thirty six patients who had just begun dialysis in nine Japanese facilities between January 2006 and October 2013 were included. Two hundred and thirty (15.0%) patients had commenced dialysis because of uremic nausea, and three hundred and ninety two (25.5%) patients had been using VDRAs before initiating dialysis. Logistic regression analysis showed that, among the medications examined in this study, only VDRA use was independently associated with a lower frequency of uremic nausea (OR 0.512, 95% CI 0.347-0.738, P = 0.0003). On the other hand, CHF and intractable edema were not associated with VDRA administration. CONCLUSION: Use of VDRAs during the predialysis period was the only factor associated with a lower prevalence of uremic nausea, suggesting that VDRAs may prevent uremic nausea in patients with advanced CKD.

Electron Microscopy and X-ray Analysis of Cr-Containing Precipitates Synthesized by Newly Isolated Actinobacterium, Flexivirga alba ST13(T.).

Chromium(Cr) precipitate synthesized by Cr(VI)-reducing bacterium Flexivirga alba ST13(T) was examined using transmission electron microscopy (TEM) and the energy dispersive X-ray (EDX). The strain showed altered-morphology after exposing to Cr(VI) in minimal medium. The resultant precipitate included bacterial pellet and needle-like structure which was similar to the structure made from Cr(OH)3 precipitate. Cr was observed in bacterial cells using TEM-EDX. Bacteria with high electron density showed the precipitation of Ca in addition to Cr. The isolated strain would be useful to precipitate Cr from Cr(VI)-containing environment.

Influence of renin-angiotensin system on serum parathyroid hormone levels in uremic patients.

INTRODUCTION: The aim of this study was to investigate the factors influencing serum parathyroid (PTH) levels, including medications for treating chronic kidney disease-mineral and bone metabolism disorder (CKD-MBD) in patients with end-stage renal disease. METHODS: We enrolled 1,076 patients in nine Japanese facilities who had begun hemodialysis (HD) due to ESRD. We investigated the relationships between intact PTH (iPTH) levels and clinical parameters and medications just prior to beginning HD. RESULTS: Significant decreases in serum iPTH levels were seen in males, in the presence of diabetes mellitus (DM), and with administration of renin-angiotensin system inhibitors (RASIs). Significant correlations were found between serum calcium and iPTH levels. In the patients administered RASIs, there was a significant decrease in serum iPTH levels with DM, male gender, and administration of active vitamin D sterols (VDs) compared with those not administered RASIs, although serum-corrected calcium levels were not different. Multiple regression analysis found gender, age, presence of DM, and serum calcium and phosphate levels to be significant contributing factors. In addition, administration of angiotensin II receptor blockers (ARBs) may also be a contributing factor to iPTH levels at the beginning HD (p = 0.050). CONCLUSIONS: In this study, serum iPTH levels were related to administration of ARBs besides gender, age, the presence of DM and serum calcium levels. Our study suggests that the RA system involve serum iPTH levels in uremic patients.

Fibroblast growth factor 23 production in bone is directly regulated by 1{alpha},25-dihydroxyvitamin D, but not PTH.

Fibroblast growth factor 23 (FGF23), which is primarily produced by osteocytes in bone, regulates renal phosphate excretion and 1α,25-dihydroxyvitamin D [1,25(OH)(2)D(3)] metabolism. Patients with chronic kidney disease (CKD) have increased levels of circulating serum FGF23, but the direct effect on circulating FGF23 levels in renal insufficiency is still unclear. To identify the major regulator of FGF23 synthesis in renal insufficiency, we compared the effect of parathyroid hormone (PTH) and 1,25(OH)(2)D(3) on FGF23 synthesis in the calvariae of normal rats with that of uremic rats in vitro. 1,25(OH)(2)D(3) treatment significantly increased the FGF23 concentration in the medium from both groups, but the degree of increase in the uremic group was markedly higher than in the control group. A significant increase in FGF23 mRNA expression occurred as early as 4 h after treatment and reached the maximum within 8 h in the uremic group, whereas in the normal group a significant increase in FGF23 mRNA expression was observed only at 8 h. In addition, the expression of vitamin D receptor (VDR) mRNA in the calvariae of uremic rats was markedly higher than in normal rats. However, in neither group did PTH treatment affect the medium FGF23 concentration or the FGF23 mRNA levels. These results suggest that FGF23 synthesis in bone is regulated by 1,25(OH)(2)D(3) directly, not by PTH, and that increased VDR mRNA expression induced the relatively swift and strong response in the uremic group.

Reduced expression of perlecan in the aorta of secondary hyperparathyroidism model rats with medial calcification.

BACKGROUND: Vascular calcification is an important complication that worsens the prognosis for dialysis patients, although its detailed molecular mechanisms are still unknown. METHODS: We produced a rat model for vascular calcification with hyperphosphatasemia and hyperparathyroidism, performing a 5/6 nephrectomy and providing a high-phosphorus, low-calcium diet for eight weeks. We examined mRNA obtained from the calcified aortae using microarray analysis, and searched for alterations in gene expression specifically in the calcified lesions. RESULTS: Medial calcification was demonstrated in the abdominal aorta of 12 out of 42 hyperparathyroidism rats. In the aortae of hyperparathyroid rats with vascular calcification, the genes for heparan sulfate proteoglycans, including perlecan, were found to be down-regulated using microarray analysis and real time PCR. Immunohistochemistry also demonstrated reduced production of perlecan in the aortae of hyperparathyroid rats. DISCUSSION: Perlecan is a major component of the vascular wall basement membrane and may play a role in protecting vascular smooth muscle cells from inflammatory cells and various toxins. It has also been reported that heparan sulfate chains may inhibit osteogenesis. Our findings indicate that perlecan may protect vascular smooth muscle cells from various factors that promote vascular calcification. CONCLUSIONS: It may be that reduced expression of perlecan in the calcified aortae of hyperparathyroid rats is a risk factor for vascular calcification.

Tolvaptan, a selective oral vasopressin V2 receptor antagonist, ameliorates podocyte injury in puromycin aminonucleoside nephrotic rats.

BACKGROUND: Proteinuria caused by glomerular disease is characterized by podocyte injury. Vasopressin V2 receptor antagonists are effective in reducing albuminuria, although their actions on glomerular podocytes have not been explored. The objective of this study was to evaluate the effects of tolvaptan, a selective oral V2 receptor antagonist, on podocytes in a puromycin aminonucleoside (PAN)-induced nephrosis rat model. METHODS: Rats were allocated to a control, PAN nephrosis, or tolvaptan-treated PAN nephrosis group (n = 9 per group). Urinary protein excretion and serum levels of total protein, albumin, creatinine, and total cholesterol were measured on day 10. The influence of tolvaptan on podocytes was examined in renal tissues by immunofluorescence and electron microscopy. RESULTS: PAN induced massive proteinuria and serum creatinine elevation on day 10, both of which were significantly ameliorated by tolvaptan. Immunofluorescence studies of the podocyte-associated proteins nephrin and podocin revealed granular staining patterns in PAN nephrosis rats. In tolvaptan-treated rats, nephrin and podocin expressions retained their normal linear pattern. Electron microscopy showed foot process effacement was ameliorated in tolvaptan-treated rats. CONCLUSIONS: Tolvaptan is protective against podocyte damage and proteinuria in PAN nephrosis. This study indicates that tolvaptan exerts a renoprotective effect by affecting podocyte morphology and probably function in PAN nephrosis. Tolvaptan is a promising pharmacological tool in the treatment of renal edema.

Mechanism of phosphate-induced calcification in rat aortic tissue culture: possible involvement of Pit-1 and apoptosis.

BACKGROUND: Hyperphosphataemia is a known contributing factor in the progression of vascular calcification in dialysis patients. The cellular mechanisms underlying phosphate-induced calcification are still unclear despite intense study, so in this study, we investigated the possible involvement of the type III sodium-dependent phosphate cotransporter, Pit-1, in an aortic tissue culture model. METHODS: Aortic segments from 9-week-old male Sprague-Dawley rats were incubated in serum-supplemented medium for 10 days. The phosphate concentration of the medium was elevated to induce calcification, which was assessed by histology and calcium content. Phosphonoformic acid (PFA) was used to inhibit phosphate uptake. The involvement of apoptosis was examined using the terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate (dUTP) nick-end labelling (TUNEL) assay, caspase 3 activation, and inhibition of apoptosis using a general caspase inhibitor. Phenotypic changes in vascular smooth muscle cells (VSMC) were assessed using expression of osteochondrogenic differentiation markers. RESULTS: Medial vascular calcification was induced in aortas cultured in a high phosphate medium. PFA decreased the rates of calcification and apoptosis of VSMC in the media, concomitant with calcification. Caspase inhibitor reduced calcification. No phenotypic transition of VSMC was seen in this model. CONCLUSIONS: These results indicate that phosphate uptake through the type III sodium-dependent phosphate cotransporter, Pit-1, leads to induction of apoptosis and subsequent calcification of VSMC.

Conjugal transformation and transposon and chemical mutagenesis of gram-negative selenate-respiring Citrobacter sp. strain JSA.

Conjugal mating between selenate-reducing Citrobacter sp. strain JSA and Escherichia coli S17-1 bearing pSUP2021 allowed transposon mutagenesis and chromosomal transformation. Kanamycin-resistant transconjugants were obtained successfully by this method from a freshwater selenate-respiring Citrobacter sp. strain JSA. The maximum frequency of kanamycin-resistant Tn5 transconjugants was 3.6 x 10(-6) per recipient of this strain. Of these transconjugants, eight strains of selenate reduction-deficient transconjugants living by nitrate reduction were obtained in the strain JSA. Moreover, the same phenotype of deficient mutant was created by chemical mutagenesis with ethylmethanesulfonate. The results strongly indicate that selenate reducing anaerobic respiration was independent of nitrate reduction in the Citrobacter sp. isolate strain JSA.

Regulation of fibroblast growth factor 23 production in bone in uremic rats.

BACKGROUND: Fibroblast growth factor 23 (FGF23) regulates renal phosphate reabsorption and 1alpha,25-dihydroxyvitamin D [1,25(OH)(2)D(3)] metabolism. Patients with chronic kidney disease (CKD) have increased levels of circulating FGF23, but the direct regulation of this elevation of FGF23 is incompletely understood. METHOD: We measured plasma parameters in uremic rats fed a high-phosphorus diet and then performed parathyroidectomy (PTX) to determine its effect. We also investigated FGF23 mRNA expression in various tissues to identify the major source of circulating FGF23. RESULT: The uremic rats displayed dramatic changes in plasma FGF23 levels, consistent with increased expression of FGF23 in bone. Elevated FGF23 was associated with phosphate and parathyroid hormone (PTH). After PTX, the elevated FGF23 had decreased, consistent with decreased expression of FGF23 in bone. Significant decreases in plasma FGF23 were associated with PTH and 1,25(OH)(2)D(3), but not phosphate. CONCLUSION: Elevated plasma FGF23 levels in uremic rats reflect the increased expression of FGF23 in bone. The expression of FGF23 in bone may be regulated by a PTH-1,25(OH)(2)D(3) axis-dependent pathway and another PTH-dependent and 1,25(OH)(2)D(3)-independent pathway in uremic rats. The pathway may be decided by the degree of renal dysfunction.

Highly concentrated calcitriol and its analogues induce apoptosis of parathyroid cells and regression of the hyperplastic gland--study in rats.

BACKGROUND: Controlling hyperplasia of the parathyroid gland (PTG) is important in the management of secondary hyperparathyroidism (SHPT). Regression of the hyperplastic PTG requires a decrease in the number of parathyroid cells (PTCs), so the present study investigated cell death caused by toxic agents or by clinically usable vitamin D metabolites. METHODS: The PTGs of Sprague-Dawley rats, which had been 5/6-nephrectomized and fed a high-phosphate diet for 12 weeks, were treated with two consecutive direct injections (DI) of calcitriol, maxacalcitol, paricalcitol, doxercalciferol or phosphate-buffered saline containing either 0.01% or 90% ethanol (0.01-ET or 90-ET, respectively). Laboratory data, including serum levels of intact parathyroid hormone (intact-PTH), were obtained before and after the treatments. The PTGs were excised 24 h after the final injection and evaluated for PTC apoptosis using light and electron microscopy, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling (TUNEL) method and DNA electrophoresis. RESULTS: Treatment with any of the vitamin D metabolites and 90-ET significantly decreased the serum intact-PTH level, but only the latter significantly decreased the serum Ca level. Either treatment markedly increased the number of TUNEL-positive PTCs, but not in PTG treated with 0.01-ET. In PTGs treated with DI of any vitamin D metabolites was there ladder formation on DNA electrophoresis, as well as the characteristic morphological features of apoptosis in both the light and electron microscopic studies. CONCLUSIONS: DI of vitamin D metabolites may be effective in controlling not only the PTH level, but also PTG hyperplasia, in advanced SHPT by, at least in part, apoptosis-induced cell death. Our study was performed in rats.

Rapid and onsite BOD sensing system using luminous bacterial cells-immobilized chip.

A BOD monitoring system based on a bio-chip which immobilized luminous bacterium in micrometer-order holes were arrayed and fabricated by micro-machine techniques, was developed. The acrylic chip (3 cmx3 cm) comprises nine micro-holes (diameter: 700 microm or 1 mm, depth: 100 microm) arranged in a three by three array. Cells of the marine luminous bacterium, Photobacterium phosphoreum IFO 13896, which was grown at 15 degrees C for 15 h, were immobilized with 3% or 15% sodium alginate gel. BOD standard solutions or actual sample solution (approximately 10 microl) was fallen onto the cell-arrayed chip, and then the chip was incubated at 25 degrees C for 25 min. After incubation, bioluminescence from the each hole was gray-scaled and measured by a chemi-imager or newly developed onsite-type-monitoring system using a digital camera and a mobile-type personal computer. BOD values less than 16 ppm could detect by the chip, in particular, linear relationship at the concentrations between 0 and 16 ppm could be observed when luminous cells were immobilized with 3% sodium alginate gel. Steady bioluminescence was observed on the chip in the presence of BOD standard solution (GGA solution) which contained mineral elements. Furthermore, simultaneous detection of BOD values in various samples could be employed in the single chip. These results showed that the monitoring system with bio-chip could achieve high-through-put and onsite BOD detection. Our newly developed onsite-type BOD detection system which was used a digital camera and a (mobile) laptop computer was applied to measure and detect organic pollution due to biodegradable substances in wastewater treatment system. The same performance as the chemi-imager system was obtained for data of bioluminescence. The obtained BOD values showed a similar correlation with that of the conventional method for BOD determination (BOD5). These results suggested for successful achievement of high-though-put and onsite detection of BOD in practical.

[Phosphate binder up to date].

It has become clear that hyperphosphatemia is the major risk factor on the patients' survival undergoing regular renal replacement therapy. One of the mechanism of this impact on survival is ectopic calcification like vascular calcification. The standard therapy for hyperphosphatemia is phosphate removal by renal replacement therapy. However, since the amount of phosphate removal with today's hemodialysis procedure is not enough, the phosphate binder as depressant of phosphate absorption is still essential. Aluminum compound had been prohibited from 1992 due to serious adverse effect like aluminum encephalopathy and osteomalacia.Calcium carbonate and sevelamer hydrochloride are common phosphate binder. The combination therapy of both phosphate binders is recommended to avoid involvement in adverse effects of the both drugs. Lanthanum carbonate is developing compound as a new and powerful phosphate binder. It is expected as a new non-calcium and non-aluminum phosphate binder with powerful phosphate binding effect. However, the adverse effect of the Lanthanum carbonate is still obscure. Further investigation is acquired.

Damage to and recovery of coastlines polluted with C-heavy oil spilled from the Nakhodka.

The damage to and recovery of the Japanese coastline from Suzu, Ishikawa Prefecture to Mikuni, Fukui Prefecture was investigated visually over three years after a C-heavy oil spill from the Russian tanker "Nakhodka" in the Japan Sea on January 2, 1997. The beached C-heavy oil tended to remain for a long time on coasts of bedrock and boulder/cobble/pebble but it was removed rapidly from coasts of gravel/sand and man-made structures such as concrete tetrapods. On the coasts of the latter type, wave energy appeared to be the main force removing the oil. One year after the spill, C-heavy oil tended to remain strongly on the sheltered coasts of bedrock and boulder/cobble/pebble. Even on coasts of this type, the contamination was remarkably absent by 2 years after the spill. The concentration levels of polycyclic aromatic hydrocarbons (PAHs) in oil lumps, sand and seawater were monitored during 3 years following the spill. The concentrations of PAHs having 2 or 3 rings decreased more quickly than did those of PAHs having 4 or more rings, suggesting that volatilization was the main cause of the decrease. On the other hand, the concentrations of PAHs having 4 to 6 rings did not start to decrease until 7 months after the spill. The main cause of the decrease seemed to be photolysis. The concentration of BaP in seawater off the polluted coasts was high 1 month after the spill and then decreased. Three years after the spill, the level fell to the sub ng/L level, which was as low as the level in seawater along unpolluted clean coasts in Japan. The concentration of BaP in greenling was higher than the normal level only during the first two months after the spill. These results suggest that the coastlines in Ishikawa and Fukui Prefectures that were polluted with C-heavy oil recovered in 3 years.

[Enhanced expression of EGFR, TGF-alpha, EGF in hyperplastic parathyroid glands in established stage of renal failure in rats].

It was reported that the parathyroid gland hyperplasia correlated with enhanced co-expression of TGF-alpha and its receptor EGFR at early stages of renal failure. This time, we investigated the time course for EGFR and its ligands, TGF-alpha, and EFG expression, and the influence of high-phosphorus (P) diet to EGFR and EGF expression, and the effect of EGFR-tyrosine kinase inhibitor (Gefitinib, [IRESSA; AstraZeneca]; TKI) in rat PTGs with established stage of renal failure. The levels of EGFR, EGF, TGF-alpha mRNA in rat PTGs were increased for the time periods. The serum intact PTH levels, and EGFR, EGFmRNA in rat PTGs were suppressed in normal-P diet group. Nuclei positive cells for PCNA in TKI group were suppressed. The levels of p21mRNA were increased in TKI group. These results suggested that the enhanced expression of EGFR, TGF-alpha and EGF participate in the cell proliferation of hyperplastic PTGs in established stage of renal failure.

Possible prevention of dialysis-requiring congestive heart failure by angiotensin-II receptor blockers in non-dialysis Japanese patients with Stage 5 chronic kidney disease.

BACKGROUND: Preventive medications for dialysis-requiring congestive heart failure (CHF) in non-dialysis Japanese patients with Stage 5 chronic kidney disease (CKD) are unknown. Our aim was to explore which CKD medication was associated with a reduced prevalence of dialysis-requiring CHF in non-dialysis Japanese patients with Stage 5 CKD. METHODS: The present multicenter, retrospective, cross-sectional study examined the association between CKD medications and the prevalence of dialysis-requiring CHF in non-dialysis Japanese patients with Stage 5 CKD. RESULTS: There were 1536 Japanese Stage 5 CKD patients who satisfied our inclusion criteria. We had 309 (20.1%) patients whom had developed dialysis-requiring CHF and 940 patients (60.8%) whom had been using angiotensin-II receptor blockers (ARBs) before initiating dialysis. In our multivariate analysis, only ARB use was significantly associated with a lower risk of CHF (Odds ratio (OR): 0.680, 95% confidence interval (CI): 0.516-0.897; p = 0.0064), of the CKD treatments examined in this study. CONCLUSIONS: We found that ARB use during the pre-dialysis period is associated with a lower prevalence of CHF in the non-dialysis Japanese patients with Stage 5 CKD, suggesting a possible prevention of dialysis-requiring CHF by ARBs, in non-dialysis Japanese patients with Stage 5 CKD.

Effects of Cyclophosphamide Pulse Therapy on the Clinical and Histopathological Findings, Particularly Crescent Formation, in a Patient with Adult-onset Steroid-refractory Henoch-Schönlein Purpura Nephritis.

A 29-year-old woman was diagnosed with Henoch-Schönlein purpura nephritis (HSPN) based on the presence of purpura and histopathological findings showing crescent formation, mesangial proliferation and IgA deposition in the glomerular mesangium. She was treated with high-dose steroids; however, the nephritic syndrome persisted. Therefore, we diagnosed her with steroid-resistant HSPN and decided to add treatment with cyclosphamide pulse therapy. After one year of treatment, the histopathological findings, including crescent formation and IgA deposition, improved, as confirmed on a renal biopsy, and the patient fulfilled the criteria for complete remission. Cyclophosphamide pulse therapy may be considered an effective treatment for intractable HSPN.

A rapid BOD sensing system using luminescent recombinants of Escherichia coli.

A biochemical oxygen demand (BOD) sensing system based on bacterial luminescence from recombinant Escherichia coli containing lux A-E genes from Vibrio fischeri has been developed. It was possible to use frozen cells of luminescent recombinants of E. coli as the bacterial reagents for measurement. Steady bioluminescence was observed during the incubation time between 90 and 150 min in the presence of a sole carbon source such as glucose, acetate, L-glutamate and BOD standard solution (GGA solution). This disposable bacterial reagent was applied to measure and detect organic pollution due to biodegradable substances in various wastewaters. The obtained values of this study showed a similar correlation with that of the conventional method for BOD determination (BOD5). Bacterial luminescence that was visualized with an imaging system using a charge coupled device (CCD) camera and a photomulti-counter demonstrated that this method could also be used for multi-sample detection of organic pollution due to biodegradable substances by using a microtiter plate. These results suggested for successful achievement of high-though-put detection of BOD in practical.

[K/DOQI clinical practice guidelines for bone metabolism and disease in CKD].

K/DOQI (Kidney Disease Outcome Quality Initiative) Clinical Practice Guidelines for Bone Metabolism and Disease in Chronic Kidney Disease were published last year. The Work Group screened enormous amount of articles and made up of sixteen guidelines for Bone metabolism and disease in Chronic Kidney Disease. This review provides brief an overview of guidelines with strong emphasis on vitamin D.