Characterisation of antibiotic resistance of Salmonella isolated from dog treats in Japan.

Dog treats might be contaminated with Salmonella. In Canada and the USA, outbreaks of human salmonellosis related to exposure to animal-derived dog treats were reported. Consequently, surveillance data on Salmonella contamination of dog treats have been gathered in many countries, but not in Japan. In the current study, we investigated whether dog treats in Japan were contaminated with Salmonella. Overall, 303 dog treats (of which 255 were domestically produced) were randomly collected and the presence of Salmonella investigated. Seven samples were positive for Salmonella enterica subsp. enterica. Among these isolates, three were identified as serovar 4,5,12:i:-; two were serovar Rissen; and two were serovar Thompson. All serovar 4,5,12:i:- and Thompson isolates were resistant to one or more drugs. Two serovar Rissen isolates were fully susceptible to all tested antimicrobial agents. All Salmonella isolates were susceptible to cefotaxime, ciprofloxacin and nalidixic acid. The gene blaTEM was detected in two serovar 4,5,12:i:- isolates. The blaCTX-M and blaCMY genes were not detected in any isolates. This study demonstrated that dog treats in Japan could constitute a potential source of dog and human Salmonella infections, including multidrug-resistant Salmonella isolates.

Prevalence of, and risk factors for, carriage of carbapenem-resistant Enterobacteriaceae among hospitalized patients in Japan.

BACKGROUND: The prevalence of carbapenem-resistant Enterobacteriaceae (CRE) has been reported to be lower in Japan than in many other countries. However, extensive surveillance for CRE carriage has not been performed in Japan. AIM: To investigate the prevalence of CRE carriage in Japan among convalescent patients considered to be at high risk of being CRE carriers using an improved selective culture medium. METHODS: A cross-sectional survey was conducted in 22 acute care hospitals (ACHs) and 21 long-term care hospitals (LTCHs) in northern Osaka from December 2015 to January 2016. Patients who used incontinence aids, an enteral feeding tube or a urinary catheter were enrolled. Faecal specimens were examined using the newly developed M-ECC for imipenemase (IMP)-producing CRE, which is the most prevalent form of CRE in Japan. The positive isolates were analysed by polymerase chain reaction and sequencing. Risk factors associated with carriage were analysed by logistic regression. FINDINGS: Among 1507 patients, 184 (12.2%) carried CRE. The percentage of positive patients was significantly higher in LTCHs (14.9%) than in ACHs (3.6%) (P<0.001). Risk factors for CRE carriage were longer hospital stay [odds ratio (OR) 2.59; 95% confidence interval (CI) 1.87-3.60], enteral feeding (OR 3.03, 95% CI 2.08-4.42) and antibiotic exposure (OR 2.00, 95% CI 1.40-2.87). Among the 233 CRE isolates identified, 223 were IMP producers; the remaining isolates did not produce carbapenemase. CONCLUSIONS: This is the first Japanese report to demonstrate the significant spread of CRE in both ACHs and LTCHs using an improved selective medium. A coordinated regional approach may help to prevent further spread.

Inhibition of macrophage migration inhibitory factor secretion from macrophages by vitamin E.

Macrophage migration inhibitory factor (MIF) was identified in rat peritoneal macrophages by Western blot analysis and its secretion into culture medium by enzyme-linked immunosorbent assay. We investigated the effect of vitamin E on MIF production in macrophages in response to phorbol 12-myristate-13-acetate (PMA), calcium ionophore A23187, and lipopolysaccharide (LPS). Intraperitoneal injections of vitamin E (5 mg per rat) for 6 successive days resulted in a significant increase of alpha-tocopherol content in peritoneal macrophages (478.3+/-90.7 ng/106 cells) compared with the control (1.5+/-0.5 ng/10(6) cells). For the control macrophages, MIF content of the medium (2.5x10(6) cells/18 ml) without stimulation was 2.27+/-0.20 ng/ml after 14 h culture, whereas stimulation with calcium ionophore A23187 (400 nM) and LPS (5.0 microg/ml) induced the elevation of MIF content to 3. 66+/-0.41 and 4.12+/-0.58 ng/ml, respectively. On the other hand, vitamin E-enriched macrophages without stimulation showed less MIF content (0.77+/-0.23 ng/ml) than the control. Similarly, the increase of MIF of vitamin E-treated macrophages was significantly suppressed after stimulation with calcium ionophore A23187 or LPS, compared with the control macrophages. From analysis of intracellular MIF content by Western blot, we found no alteration of intracellular MIF content of vitamin E-macrophages, in contrast to the decreased content of control stimulated-macrophages. Taken together, these results indicate that vitamin E may contribute to the regulation of immune responses through regulation of MIF secretion.

The regional distribution and cellular localization of mRNA encoding rat prostacyclin synthase.

The cloned cDNA for rat prostacyclin synthase was found to contain a 1503-bp open reading frame which encoded a 501-amino acid protein sharing 84.0% identity with the human enzyme. RNA blot analysis revealed that the rat prostacyclin synthase mRNA, as a single species of 2.1 kb, is expressed abundantly in the aorta and uterus. High levels of expression were also observed in the stomach, lung, heart, testis, liver, and skeletal muscle. Low but significant expression was also seen in the brain and kidney. Furthermore, the regional distribution and cellular localization of prostacyclin synthase mRNA were examined by in situ hybridization analysis of rat tissue sections. The definitive signals for the mRNA were localized in smooth muscle cells of the arteries, bronchi and uterus, and in the cells of the fibrous tunic surrounding the seminiferous tubules, which are characterized as smooth muscle cells. Besides smooth muscle cells, signals were also detected in the fibroblasts of the heart myocardium, lung parenchyma cells and kidney inner medulla tubules and interstitial cells.

Abundant expression of thromboxane synthase in rat macrophages.

The cloned cDNA for rat thromboxane (TX) synthase with a size of 1851 bp contained a 1599-bp open reading frame which encoded a 533-amino acid protein sharing 79.7% identity with human TX synthase. RNA blot analysis was carried out with rat cells and tissues. Rat peritoneal macrophages most abundantly expressed mRNA for TX synthase, and its level was not changed by in vivo stimulation of casein. Bone marrow, spleen, lung and thymus also expressed the TX synthase gene. These findings suggest the possibility that TXA2 plays a role in the immune system.

Effect of coffee consumption on bone metabolism.

The effects of coffee on bone metabolism are still controversial, although several studies have suggested that caffeine and/or heavy coffee consumption is associated with a significant increase in risk of fracture, osteoporosis, and periodontal disease. Therefore, we sought to clarify the relationship between coffee consumption and bone metabolism using male Wistar rats. Forty-eight male Wistar rats were assigned to three treatment groups including a control-diet group (control, n = 16, coffee-free diet), a 0.62% coffee-diet group (low caffeine, n = 16, diet supplemented with 6.2 g/kg of the control diet), and a 1.36% coffee-diet group (high caffeine, n = 16, diet supplemented with 13.6 g/kg of the control diet), and animals were maintained on an experimental diet for 140 days. Although caffeine in serum was not detected in rats fed the control diet, low-intake coffee for 140 days led to an increase in caffeine concentration to 0.53 +/- 0.11 microg/mL and high-intake coffee led to an increase of 1.77 +/- 0.22 microg/mL. No significant differences in body weight change, serum and urinary biochemical markers of bone metabolism, and bone histomorphometry were found between the coffee-diet groups and the control-diet group, except that urinary phosphorus excretion after 140 days of both coffee diets was significantly increased compared with controls (p < 0.05). In addition, the coffee diets were not associated with differences in tumor necrosis factor-alpha and interleukin-6, which have been implicated in the pathogenesis of bone loss together with interleukin-1beta. In conclusion, the present study strongly indicates that coffee does not stimulate bone loss in rats.

Selective urinary excretion of phosphatidyl ethanolamine in patients with chronic glomerular diseases.

Urinary phospholipids and lipoproteins in chronic glomerular diseases were analyzed. The subjects used were 26 patients consisting of 14 with chronic glomerulonephritis and 12 with nephrotic syndrome. Nine healthy normals served as controls. Phospholipids were isolated by one-dimensional thin-layer chromatography (TLC) using an internal standard for quantification and partially by two-dimensional TLC and, furthermore, quantified by two different methods to ascertain the kinds of phospholipids. Urinary lipoproteins were isolated by density gradient ultracentrifugation and analyzed by electrophoresis. The urinary excretion of phosphatidyl ethanolamine (PE) was recognized exclusively in the patient group and that of phosphatidyl serine (PS) in most cases with nephrotic syndrome. The daily urinary PE excretion rate was closely correlated to the urinary albumin excretion rate. However, phosphatidyl choline (PC) and sphingomyelin (SPH), which are main phospholipids in serum and red blood cell membranes, in most cases were hardly detected in urine. These observations were confirmed by two-dimensional TLC using valuable spot tests for identification of phospholipids and also by the two different quantification methods. In density gradient ultracentrifugation, urinary lipoproteins did not form such peaks as seen in the profiles of serum lipoproteins. The presence of urinary lipoproteins in two nephrotic patients has been shown, but although the method used was not very sensitive, it was suggested that lipoproteins were hardly excreted into urine as the lipoprotein deficient fraction (LPDF) (d greater than 1.21 g/ml), in which albumin is predominant. PE was found mainly in LPDF of urine, although the amount of PE in urinary lipoproteins was very limited.(ABSTRACT TRUNCATED AT 250 WORDS)

Involvement of MCP-1 and M-CSF in glomerular foam cell formation in ExHC rats.

BACKGROUND: An increase in glomerular macrophages (MO) is considered a potential effector mechanism by which hypercholesterolemia exacerbates glomerular injury. To investigate the mechanism underlying recruitment of MO into glomeruli, the expression of glomerular monocyte chemoattractant protein-1 (MCP-1) and macrophage colony-stimulating factor (M-CSF) mRNA were examined using a lipid-induced glomerular injury rat model. METHODS: Eight-week-old male ExHC rats, a strain susceptible to hyperlipidemia, were divided into the following 4 groups: a control group (C), a high cholesterol diet group (HH), a high cholesterol diet/standard diet group (HN), which were fed a high cholesterol diet for the first 4 weeks and a standard diet for the following 4 weeks, and a probucol-treatment group (PT). Both MCP-1 and M-CSF mRNA expression in glomeruli were analyzed using the RT-PCR method. An additional experimental group (M) fed a high cholesterol diet was administered M-CSF daily for 4 weeks. RESULTS: The expression of MCP-1 mRNA in glomeruli increased accompanied by an increased total serum cholesterol level in HH and HN. However, M-CSF mRNA expression was significantly suppressed at 1 or 2 weeks and gradually increased to almost basal levels. In the PT group, MCP-1 mRNA expression was suppressed. The early suppression of M-CSF mRNA expression was inhibited in PT. Renal histology showed a significant increase in foam cells in glomeruli in HH and HN rats at 4 weeks. HH rats showed increased and expanded foam cells at 8 weeks. In HN rats, however, foam cells decreased significantly after the transfer to a standard diet from a high cholesterol diet. The MCP-1 mRNA expression was suppressed after the transfer. In the PT group, foam cell formation was also suppressed. Foam cells were identified as MO. M-CSF-treatment significantly suppressed foam cell formation in glomeruli when compared with the untreated group levels. CONCLUSION: These findings suggest that hypercholesterolemia stimulated the expression of MCP-1 in glomeruli and attracted the MO into glomeruli. They also suggest that the reduction of hypercholesterolemia after the change in diet or treatment with probucol suppressed glomerular injury by suppressing the glomerular MCP-1 expression. M-CSF may suppress the recruitment of MO into glomeruli and foam cell formation at an early stage of hypercholesterolemia-induced glomerular injury.

Lysophosphatidylcholine induces platelet-derived growth factor gene expression in a human mesangial cell line.

BACKGROUND: Oxidized low-density lipoprotein (oxLDL) has been considered important in the pathogenesis of progressive renal injury. Lysophosphatidylcholine (lysoPC) is a major phospholipid component of oxLDL. On the other hand, platelet-derived growth factor (PDGF) has also been implicated in proliferative disease of the kidney. This study investigated the difference in the potential of PC and lysoPC to induce DNA synthesis and PDGF gene expression in a human glomerular mesangial cell line (HMCL). METHODS: DNA synthesis in HMCL was measured by [3H] thymidine incorporation. The mRNA expression levels of the PDGF A chain and B chain genes were measured using reverse transcription-polymerase chain reaction. RESULTS: LysoPC treatment up-regulated the [3H] thymidine incorporation level in a dose-dependent fashion. The [3H] thymidine incorporation level in HMCL coincubated with lysoPC started to increase after 4 hours of treatment, peaked at 24 hours, and decreased thereafter. The level in HMCL incubated with 100 microM of lysoPC (palmitoyl or stearoyl) increased to 7- or 10-fold of the control at peak time, respectively. However, PC treatment did not increase [3H] thymidine incorporation in HMCL. PC treatment did not induce mRNA expression of either PDGF A or B chain genes. LysoPC did not induce PDGF A chain mRNA expression either. The only B chain mRNA expression was induced by lysoPC. The mRNA expression level in HMCL treated with 50 microM lysoPC for two hours increased to 1.6-fold that of the control. CONCLUSION: LysoPC may induce DNA synthesis in a mesangial cell through the induction of PDGF BB as an autocrine and paracrine growth factor.

Vitamin E treatment of experimental glomerular disease in rats.

BACKGROUND: Kidney mesangial cells (MCs) and vascular smooth muscle cells (VSMCs) are closely related in terms of origin, microscopic anatomy, histochemistry, and contractility. This relationship suggests a similarity between kidney glomerular sclerosis and atherosclerosis. Vitamin E appears beneficial in the prevention and treatment of coronary heart disease and it also inhibits the proliferation of VSMCs in vitro. Thus, we investigated the effect of vitamin E on glomerular sclerosis and MC-proliferative glomerulonephritis (GN) in two rat models of glomerular disease. METHODS: A remnant kidney rat model accelerated with hyperlipidemia was used to examine progressive glomerular sclerosis leading to chronic renal failure. A rat model of MC-proliferative GN was induced by the intravenous administration of absorbed rabbit anti-rat thymocyte serum (ATS). RESULTS: In the remnant kidney rat model, dietary supplementation with vitamin E (500 IU dl-alpha-tocopheryl acetate/kg) and cholesterol (2%) significantly inhibited glomerular sclerosis and macrophage infiltration in glomeruli relative to controls receiving basal and cholesterol-supplemented diets. In the ATS-induced GN model, glomerular cell proliferation (principally MCs) was lower in rats fed diets supplemented with vitamin E (1000 IU dl-alpha-tocopheryl acetate/kg) compared with controls fed the basal diet only. Although the degree of glomerular macrophage infiltration was similar in both groups, fewer proliferative cell nuclear antigen (PCNA)-positive cells were observed in the vitamin E group, suggesting that MC proliferation was suppressed via the inhibition of intracellular transduction. CONCLUSIONS: Supplemental dietary vitamin E suppresses MC proliferation and glomerular sclerosis in models of glomerular disease in rats. This action of vitamin E in experimental nephritis suggests the value of clinical trials testing the potential benefit of vitamin E in chronic GN patients.

Ongoing clinical trials of lipid reduction therapy in patients with renal disease.

BACKGROUND: Lipid abnormalities in renal disease are associated with both a progressive decline in renal function and cardiovascular complications. Whether or not lipid anomalies are causal is not yet clear. Experimental studies have demonstrated that potentially atherogenic lipoproteins, such as low density lipoproteins (LDL), are associated with renal pathophysiological changes that result in progressive glomerular and interstitial damage and an ultimate reduction in renal function. These findings indicate that hyperlipidemia accelerates glomerular and interstitial damage in renal disease. Clinical studies also show that renal function declines more rapidly among patients with primary renal disease or diabetic nephropathy who have hyperlipidemia. However, few reports have demonstrated the effect of hypolipidemic agents on the progression of renal function among patients with renal disease, and those renal patients who were treated with lipid-lowering agents have not been clinically studied under large-scale controlled conditions. In addition, although cardiovascular complications are the most important factors associated with mortality in dialysis patients, randomized, large-scale trials studying the relationship between therapeutic intervention by lipid-lowering agents and prevention of cardiovascular complications have not been implemented. METHODS: We reviewed controlled and uncontrolled reported studies that examined the effects of lipid-lowering therapy in patients with renal disease. RESULTS: Most studies showed that 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors reduce cholesterol-rich apolipoprotein (apo)B-containing lipoproteins with no effects on renal function or proteinuria among patients with progressive renal disease. Small uncontrolled studies show that simvastatin and probucol moderately reduce proteinuria among patients with membranous nephropathy. One small retrospective study showed that long-term vitamin E therapy reduces aortic calcification in dialysis patients. CONCLUSIONS: Prospective, randomized large-scale trials including ongoing clinical trials of lipid reduction therapy and therapeutic interventions such as the use of the combination therapy with hypolipidemic agents and angiotensin converting enzyme (ACE) inhibitors, vitamins, or LDL apheresis are urgently required. Such trials will clarify the effect of treating dyslipidemia on the progression of renal insufficiency and dialysis-related cardiovascular complications.

Evaluation of serum lipid abnormalities in chronic nephritis.

BACKGROUND: In glomerular disease, disorders of lipid metabolism are suspected as factors exacerbating glomerular dysfunction. Although many reports have been published regarding metabolic disorders of lipids in renal disease, including nephrotic syndrome and chronic renal failure, there have been few published reports describing metabolic disorders of lipids in chronic nephritis. Therefore, in patients with IgA nephritis, we evaluated correlations between serum lipid levels and renal function and proteinuria. METHODS: In 191 patients with IgA nephritis, we evaluated the correlations between serum lipid levels and renal function [creatinine clearance (CCr)] and proteinuria (UP). Serum lipids examined included total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoproteins, phospholipids (PL), lipoprotein(a) [Lp(a)], and malondialdehyde (MDA). RESULTS: Significant correlations were observed between serum lipid levels and CCr, UP, and age. There were no abnormalities in the mean values of respective serum lipids examined. Although TC levels increased with age, HDL-C levels were not correlated with age. Hyperlipidemia was observed in 39.8% of subjects. Significant correlations were observed between levels of TC, TG, PL, LDL-C, apoB, apoC-II, and apoC-III and Ccr, UP, and age. Significant correlations were also observed between levels of MDA, apoB/apoA-I, apoE/apoC-III, and Ccr and age, as well as between apoE levels and UP and age. The levels of apoA-I and apoA-I/apoA-II ratio were significantly correlated with UP alone, whereas the apoC-II/apoC-III ratio was significantly correlated with Ccr alone. There were no significant correlations between levels of HDL-C, apoA-II, and Lp(a) and Ccr, UP, and age. CONCLUSIONS: Age, proteinuria, and renal function were related with changes in serum lipid levels in IgA nephritis. There were correlations between proteinuria and levels of apoA, as well as between renal function and apoC levels.

Lysophosphatidylcholine up-regulates IL-1 beta-induced iNOS expression in rat mesangial cells.

BACKGROUND: Nitric oxide (NO), a simple molecule synthesized from L-arginine by NO synthases (NOS), has been identified to play an important role in cell communication, cell defense and cell injury. Several studies have shown that glomeruli from rats with immune-mediated glomerular inflammation have increased production of NO. Recently, it was also reported that inducible NOS (iNOS) is localized in mesangial cells, glomerular epithelial cells and infiltrating cells in the diseased human glomeruli. On the other hand, while oxidized low density lipoprotein (ox-LDL) has been suggested to be related to progression of glomerular disease, the mechanism remains unknown. We investigated the effect of lysophosphatidylcholine (LPC), a modified phospholipid produced during LDL oxidation, on iNOS expression in rat mesangial cells. METHODS AND RESULTS: Treatment of mesangial cells with interleukin-1 beta (IL-1 beta) induced iNOS activity measured as nitrite levels in cell culture supernatants. Treatment with LPC had no effect. In contrast, coincubation with LPC and IL-1 beta resulted in a markedly higher nitrite content compared to that after incubation with IL-1 beta alone. Western blot analysis revealed that LPC caused a significant increase in the formation of iNOS protein in the presence of IL-1 beta. CONCLUSION: These findings suggest that LPC may contribute to progression of glomerular inflammation by augmenting IL-1 beta-induced iNOS expression.

Phospholipase A2 activity in ox-LDL-stimulated mesangial cells and modulation by alpha-tocopherol.

BACKGROUND: Oxidized LDL increases the production of both prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) in rat mesangial cells. These increases were suppressed by antioxidants such as alpha-tocopherol (alpha-Toc) or probucol. METHODS: We investigated the mechanism by which oxidized LDL leads to an increase in PGE2 production using rat mesangial cells in culture. We also examined how alpha-Toc supresses this augmentation, by measuring intracellular Ca2- and phospholipase A2 (PLA2) activity. RESULTS: In rat mesangial cells, oxidized LDL increased PLA2 activity by increasing the intracellular calcium ion content, which resulted in the induction of PGE2 production. On the other hand, pretreatment of cells with alpha-Toc, which resulted in a large uptake of alpha-Toc in cell membranes, markedly suppressed the augmentation of PGE2 production and PLA2 activity by oxidized LDL in a dose dependent manner. However, cytosolic PLA2 partially purified from mesangial cells was not inhibited by alpha-Toc despite an increase of alpha-Toc. CONCLUSION: These results suggest that the augmentation of PLA2 activity in mesangial cells by oxidized LDL in a result of oxidative stresses, and that the antioxidant action of alpha-Toc is responsible for the suppression of augmentation of PLA2 activity observed in mesangial cells exposed to oxidized LDL.

Erythropoietin supplement increases plasma lipoprotein lipase and hepatic triglyceride lipase levels in hemodialysis patients.

BACKGROUND: We reported in previous studies that plasma triglyceride levels, as well as remnant-like particles-cholesterol (RLP-C) and -triglyceride (RLP-TG) levels, were significantly lower in maintenance hemodialysis (HD) patients treated with erythropoietin (EPO) than in HD patients treated without EPO. However, little is known about the mechanisms underlying the improvements in abnormal RLP metabolism in HD patients. This study investigates whether EPO supplement therapy in cases of uremic anemia increases the plasma lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) levels in HD patients. METHODS: Twenty HD patients who had not previously received EPO were divided into two groups according to the stage of HD: 12 at the initial stage, defined as a mean HD duration of 0.35 +/- 0.68 months (range of 0 to 2.47 months), and 8 at the maintenance stage, defined as a mean HD duration of 114.1 +/- 91.9 months (range of 13.0 to 253.9 months). Fasting plasma was collected from the HD patients prior to the start of the EPO supplement therapy and at one month after the therapy. RLP-C levels were determined using a RLP-C JIMRO II kit. Fasting plasma was also collected from the HD patients 10 minutes after an intravenous injection of heparin (30 U/kg body wt). Plasma LPL levels were determined using an enzyme immunoassay, and HTGL levels were determined using a modified version of the Hernell et al method. RESULTS: Plasma RLP-C levels showed a tendency to decrease after the start of the EPO supplement therapy in HD patients at the maintenance stage. Plasma LPL levels were significantly higher in the two groups of HD patients one month after the start of the EPO supplement therapy than in the same patients prior to the start of the EPO supplement therapy. Plasma HTGL levels were significantly higher in HD patients at the maintenance stage one month after the start of the EPO supplement therapy than in HD patients at the maintenance stage prior to the start of the EPO supplement therapy. CONCLUSIONS: The results of this study suggest that the EPO supplement therapy may reduce plasma RLP-C levels by increasing the plasma LPL and HTGL levels in maintenance-stage HD patients.

Factors associated with calcification of the abdominal aorta in hemodialysis patients.

BACKGROUND: Cardiovascular and cerebrovascular injury caused by arteriosclerosis has been the major cause of the death in hemodialysis (HD) patients. We quantitatively analyzed and evaluated the severity of abdominal aortic calcification in HD patients in comparison to risk factors for arteriosclerosis. METHODS: One hundred thirty-seven HD patients were examined. Using image analysis software, areas of the calcified abdominal aorta were quantitatively analyzed on plain computerized tomography images. Other factors such as blood pressure (BP), lipid levels, and calcium (Ca) x phosphorus (Pi) value were also analyzed. RESULTS: Patients with a higher one-year average of systolic BP showed a higher severity of abdominal aortic calcification. That is, the severity of abdominal aortic calcification in patients with a one-year systolic BP average above 160 mm Hg was 31.5 +/- 13.6%, and this severity was significantly higher than that in patients with a one-year systolic BP average of less than 120 mm Hg (8.0 +/- 7.7%, P < 0.01). The severity of abdominal aortic calcification in patients demonstrating risk values of ectopic calcification, that is serum Ca x Pi > or = 60 (mg/dl), on more than 4 of 24 measurements within one year (25.8 +/- 13.6%) was significantly higher than the severity of aortic calcification in patients demonstrating this value less than four times in one year (P < 0.05). There was no correlation between levels of low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride, lipoprotein(a), and severity of abdominal aortic calcification. CONCLUSIONS: Systolic BP levels and the product of serum Ca and Pi were related to the severity of abdominal aortic calcification in HD patients. These observations suggested that BP control, as well as control of serum Ca and Pi levels, was important in preventing the progression of abdominal aortic arteriosclerosis.

Phosphotyrosine of macrophage by low-density lipoproteins from hemodialysis patients.

BACKGROUND: Because of the possible importance of tyrosine phosphorylation in the signal transduction process, we investigated whether an interaction of low-density lipoprotein (LDL) from hemodialysis patients (HD-LDL) and human macrophages induces tyrosine-phosphorylated proteins in the macrophages. METHODS: Human monocyte-derived macrophages were incubated with HD-LDL (100 micrograms/ml) or native LDL (100 micrograms/ml) for 15 minutes at 37 degrees C. Whole cells were lyzed with Tris-HCl buffer containing vanadate and Triton X-100. After centrifugation, lyzed proteins were divided into Triton-soluble and -insoluble fractions. Both fractions (soluble and insoluble) were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and were electroblotted onto a polyvinylidene difluoride (PVDF) membrane. Immunoblotting was performed using an antibody against phosphotyrosine or c-Src. RESULTS: Several proteins in the range 40 to 100 kDa were found to be phosphorylated constitutively in the macrophages and not affected by the addition of HD-LDL. HD-LDL did not induce any tyrosine-phosphorylated proteins either in the soluble or insoluble fractions. Macrophages pretreated with tyrosine kinase inhibitor genestein drastically inhibited tyrosine phosphorylation of these proteins. The nonreceptor tyrosine kinase, c-Src p60, was also strongly tyrosine phosphorylated in the macrophages, and this was not enhanced by the stimulation of HD-LDL. CONCLUSION: These data suggest that tyrosine autophosphorylated proteins may play a role in the early step of signal transduction in the macrophages.

Effect of vitamin E on lipid metabolism and atherosclerosis in ESRD patients.

BACKGROUND: Oxidative stress is enhanced in patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD). Bioincompatibility represents an important source of reactive oxygen species. HD patients exhibit altered anti-oxidative defences and anti-oxidative vitamins such as vitamin E and C are altered in uremia. Frequently, HD patients also suffer from atherosclerotic cardiac disease. We have previously reported that low density lipoprotein (LDL) of HD patients is rich in malondialdehyde (MDA), an end product of lipid peroxidation. MDA rich LDL is thought to be an atherogenic lipoprotein due to its enhancement of macrophage foam cell formation. METHODS: We conducted a controlled study for two years comparing the effects of a vitamin E coated cellulose membrane dialyzer and an ordinary cellulose membrane dialyzer on lipid metabolism and the progress of atherosclerosis. LDL-MDA and oxidized LDL (ox-LDL) were measured in HD patients using these two types of dialyzers. Plasma vitamin E and lipid concentrations were also evaluated. The aortic calcification index (ACI) was evaluated by CT scan to assess the progress of atherosclerosis before and for every year after treatment. RESULTS: Use of a vitamin E coated cellulose membrane dialyzer for six months, one year and two years resulted in a significant reduction in LDL-MDA and ox-LDL compared to the ordinary cellulose membrane dialyzer. Treatment with a vitamin E-coated dialyzer significantly reduced the percentage increase in ACI after 24 months compared to the control. There were no significant changes in plasma vitamin E and lipid concentrations between the two groups. CONCLUSIONS: These results suggest that the oxidative stress could be one of the stimulating factors of abnormal lipid metabolism and atherosclerosis in ESRD patients.

Effect of simvastatin on the lipid profile of hemodialysis patients.

BACKGROUND: Simvastatin, a 3-hydroxy 3-methylglutaryl co-enzyme A (HMG-CoA) reductase inhibitor, is used widely for treatment of hypercholesterolemia. Simvastatin may be a suitable treatment for dyslipidemia in hemodialysis (HD) patients. However, investigation of the side-effects and safety of long-term administration of simvastatin to HD patients has been limited. In this study, we investigated the effects and safety of simvastatin and its effects on lipoprotein metabolism in hypercholesterolemic patients on HD. METHODS: Simvastatin was administered at a dosage of 5 mg/day for 24 weeks to 38 HD patients with high serum total cholesterol (TC) levels (200 mg/dl) or low high-density lipoprotein cholesterol (HDL-C) levels (35 mg/dl). Every four weeks, serum lipids, apolipoprotein, lipoprotein (a) [Lp(a)] and malondialdehyde (MDA) levels were measured. In addition, lipid levels were determined in each lipoprotein fraction separated by ultracentrifugation. RESULTS: After 24 weeks of simvastatin administration, TC significantly decreased by 25.7%, and low-density lipoprotein cholesterol (LDL-C) was significantly decreased by 33.6%. Triglyceride (TG) and HDL-C showed no significant changes. Apolipoprotein (apo) B significantly decreased by 24.5% and apo E by 30.0%. No significant changes were observed in the other apolipoproteins. MDA was also significantly decreased, whereas Lp(a) was not significantly altered. In the lipoprotein fractions, very LDL cholesterol (VLDL-C), intermediate-density lipoprotein cholesterol (IDL-C), LDL1 cholesterol (LDL1-C), and LDL2 cholesterol (LDL2-C) showed significant decreases. No particular side-effects were observed during the 12 months of simvastatin administration. CONCLUSIONS: These results suggest that simvastatin appears to be safe and effective in HD patients with hypercholesterolemia.