Yoji Nishida

Effect of lipoproteins on cultured human mesangial cells

It was recently reported that low-density lipoprotein (LDL) promotes mesangial cell proliferation, and oxidized LDL is cytotoxic for mesangial cells. However, there have been few studies about the effects of other lipoproteins on mesangial cells. Accordingly, we investigated the effect of various lipoproteins on cultured human mesangial cells using 3H-thymidine (3H-TdR) incorporation and cell counting assays. We also investigated the levels of several cytokines in mesangial cell culture supernatants after stimulation by the lipoproteins. Addition of very-low-density lipoprotein (VLDL) at concentrations up to 100 micrograms/mL, intermediate-density lipoprotein (IDL) at up to 50 micrograms/mL, and LDL at up to 50 micrograms/mL induced the proliferation of cultured human mesangial cells, whereas cell growth was inhibited at higher concentrations. Oxidized LDL caused a concentration-dependent decrease of 3H-TdR incorporation. High-density lipoprotein (HDL) had no proliferative effective effect at any concentration. Exposure to VLDL, IDL, LDL, or a high concentration of HDL enhanced the secretion of interleukin-6, platelet-derived growth factor, and transforming growth factor-beta by mesangial cells, whereas tumor necrosis factor-alpha secretion was stimulated by oxidized LDL. These finding indicate that triglyceride (TG)-rich lipoproteins (VLDL and IDL) promote mesangial cell proliferation as well as LDL, whereas oxidized LDL has the reverse effect. These effects of lipoproteins may be related to modulation of various cytokines. Accordingly, TG-rich lipoproteins, LDL, and oxidized LDL may be involved in mesangial cell proliferation and injury in patients with mesangial proliferative glomerulonephritis.

Effect of pH and Glucose on Cultured Human Peritoneal Mesothelial Cells

OBJECTIVE We investigated the effects of various pH and glucose concentrations on the growth of human peritoneal mesothelial cells and on coagulation and fibrinolytic factors. MATERIALS AND METHODS Cells were cultured at various pH values in Hams F-12 medium containing 1.0% foetal calf serum and supplemented with D-glucose or D-mannitol at various concentrations. After 4-48 h, cell proliferation and 3H-thymidine incorporation were determined. Coagulation and fibrinolytic factors were measured after 48 h. RESULTS Glucose caused concentration-dependent inhibition of cell growth at all pH values, but the deleterious effect of low pH on cell proliferation was faster and stronger than that of high glucose. At a similar osmolality, mannitol caused less inhibition of cell proliferation than glucose. There was a glucose concentration-dependent increase of thrombin-antithrombin III complex production at all pH values. At pH 5.2, tissue-type plasminogen activator production was far lower than at higher pH values, and production of the plasminogen activator inhibitor showed a glucose concentration-dependent increase. At pH 6.5 or 7.3, however, the plasminogen activator inhibitor production decreased and tissue-type plasminogen activator production increased in a glucose concentration-dependent manner. CONCLUSIONS Low pH and/or high glucose culture medium had an inhibitory effect on peritoneal mesothelial cells, with the effect of high glucose being partially related to hyperosmolality. These cells may modulate peritoneal coagulant and fibrinolytic activity, with the balance between coagulation and fibrinolysis being disturbed by low pH and/or high glucose.

Remnant-Like Particle Cholesterol May Indicate Atherogenic Risk in Patients on Chronic Hemodialysis

Recently, involvement of remnant-like particle cholesterol (RLP-C) in atherosclerosis was reported, but this parameter has not been adequately investigated in hemodialysis (HD) patients. The present study investigated the relationship between the RLP-C level and total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), lipid peroxides (malone dialdehyde, MDA), apolipoprotein (Apo) A-I, and ApoB. In addition, the fractions of very low density lipoprotein (VLDL), intermediate density lipoprotein (IDL), LDL, and HDL in serum lipoproteins were determined by disk polyacrylamide gel electrophoresis. The relationship between the RLP-C level and three atherogenic indices was also studied. The RLP-C level in HD patients (8.2 +/- 6.7 mg/dl) was significantly higher than that in normal controls (2.7 +/- 1.3 mg/dl). The RLP-C level showed a significant positive correlation with the levels of TC, TG, LDL-C, MDA, ApoB, VLDL(%), and IDL(%), as well as a negative correlation with HDL(%). However, there was no correlation with age or the duration of HD. RLP-C also showed significant positive correlations with the (TC -HDL-C)/HDL-C ratio and the (VLDL + LDL)/HDL ratio, as well as a negative correlation with the ApoA-I/ApoB ratio. These results suggest that RLP-C may be a potential indicator of atherogenic risk in HD patients.

Lipid-lowering therapy and coagulation/fibrinolysis parameters in patients on peritoneal dialysis.

Patients on continuous ambulatory peritoneal dialysis (CAPD) often have abnormalities of lipid metabolism or coagulation and fibrinolysis, these patients may thus be more susceptible to atherosclerosis than those on hemodialysis. It has been reported that hypercoagulability and hyperfibrinolysis are correlated with abnormalities of lipid metabolism. Therefore, we investigated the effect of a decrease in lipids on the coagulation and fibrinolysis system in CAPD patients with hyperlipidemia who received lipid-lowering therapy. The patients included 5 men and 13 women, with a mean age of 52.5 years. Pravastatin sodium (10 mg/day) and ethyl icosapentate (1800 mg/day) were administered concomitantly for 8 weeks. Lipid levels and coagulation/fibrinolysis parameters were measured before and after therapy. The patients were divided into two groups depending on their response to therapy: responders showed a decrease in total cholesterol or triglycerides by at least 20% and non-responders showed less improvement. In the responders, the levels of protein C, tissue plasminogen activator/plasminogen activator inhibitor-I complex, factor XIII, α2-plasmin inhibitor, and D-dimer were significantly lower after therapy than before therapy. Protein C, factor XIII, and α2-plasmin inhibitor were also significantly decreased after therapy in non-responders, but the extent of the decrease was smaller. The plasminogen level was significantly increased after therapy in non-responders. These findings suggest that a decrease in lipid levels and/or some other action by lipid-lowering agents may correct abnormalities of coagulation and fibrinolysis in CAPD patients. (Int J Artif Organs 2000; 23: 27–32)

Apolipoprotein E Polymorphism in IgA Nephropathy

Background/Aim: To clarify the role of the apolipoprotein E (Apo E) phenotype in IgA nephropathy, we investigated its relationship with histological damage and clinical factors. Methods: The subjects were 104 consecutive patients (41 men and 63 women) with IgA nephropathy. The Apo E phenotype was identified by plasma isoelectric focusing and immunoblotting, and the frequencies of Apo E alleles were calculated. Results: The frequencies of the phenotypes and the alleles were as follows: 2/2 = 0, 2/3 = 0.086, 3/3 = 0.654, 2/4 = 0.010, 4/3 = 0.211, 4/4 = 0.010, 3/5 = 0.029, Ε2 = 0.048, Ε3 = 0.817, Ε4 = 0.120, and others = 0.015. There were no significant differences between the IgA nephropathy patients and healthy individuals in the frequencies of Apo E phenotypes and the alleles. However, the Apo E2 phenotype was significantly more common among patients with severe histological damage than in those with mild damage. The serum triglyceride levels were significantly elevated, and the Apo E2 phenotype was significantly more prevalent in patients with severe histological damage as compared with those with mild damage. Conclusion: The Apo E2 phenotype appears to be associated with the severity of histological damage in IgA nephropathy.

Advanced Glycation End-Products Reduce the Viability of Human Peritoneal Mesothelial Cells

Accessible online at: http://BioMedNet.com/karger Dear Sir, Advanced glycation end-products (AGEs) are produced by nonenzymatic glycation of proteins through the Maillard reaction. The accumulation of AGEs is considered to be one of the causes of aging. It has been reported recently that AGEs promote the development of vascular complications in diabetes mellitus and are involved with the development of glomerulosclerosis in patients with diabetic nephropathy [1]. It has also been reported that the level of serum AGEs is increased in patients who are treated with long-term continuous ambulatory peritoneal dialysis (CAPD) [2]. Patients who are treated with CAPD suffer from problems related to peritoneal dysfunction. Dobbie [3] reported that this peritoneal dysfunction is caused by peritonitis, or longterm use of dialysate in environments of high concentrations of glucose and low pH. Degenhardt et al. [2] reported that many of these patients have a metabolic abnormality, such as an abnormality in lipid metabolism due to the absorption of glucose from the dialysate, and that renal dysfunction causes an increase in the level of serum AGEs. Peritoneal dysfunction may be caused by the serum AGEs becoming trapped in the peritoneal tissues during the process of dialysis, or by proteins in the peritoneal tissues being glycated by the high concentrations of glucose. All of these studies suggest that patients who are treated with CAPD are placed under conditions which cause the accumulation of AGEs in their peritoneal tissues. In fact, Nakayama et al. [4] have shown through immunohistological studies that AGEs accumulate Fig. 1. [3H]-thymidine incorporation of human peritoneal mesothelial cells were incubated with AGEs for 24 h. AGEs were recognized by anticarboxymethyl monoclonal antibody in this study. All experiments were done in triplicate. Data are expressed as mean B SD. Statistical analysis was done using ANOVA (* p ! 0.05, ** p ! 0.01). ✽✽

PARENT AND CHILD CASES OF IGA NEPHROPATHY ASSOCIATED WITH VON RECKLINGHAUSEN'S DISEASE

Yoshihiko Taniguchi, MD, Second Department of Internal Medicine, Hiroshima University School of Medicine, 1-2-3 Kasumi, Minami-Ku, Hirsohima City 734 (Japan) Table 1. Serological typing for HLA-A, -B, -C, -DR, and -DQ antigens Dear Sir, We present parent and child cases of IgA nephropathy associated with von Recklinghausen’s disease. Case 1: In April 1987, a 41-year-old woman was referred to our department because of episodes of proteinuria and occult hematuria concomitant with febrile upper respiratory tract infections. A renal biopsy done at this time revealed IgA nephropathy, moderate degree. In 1988, she was diagnosed as having von Recklinghausen’s disease at the Dermatology Department of our hospital. In 1995, her renal function deteriorated gradually, so she was admitted for a second renal biopsy. Physical examination revealed multiple soft, small tumoral masses, which were pathologically diagnosed as being fibro-mas, along with café-au-lait spots and diffuse freckles. Her extremities were also slightly edematous. Abnormal laboratory findings were: urinary protein 2+, occult hematuria 3+, urinary protein excretion 0.8 g/day, BUN 19 mg/dl, serum creatinine 0.89 mg/dl, uric acid 6.0 mg/dl, creatinine clearance 58.5 ml/min, and serum ß2microglobulin 2.79 μg/ml. Her serum IgA level was normal. Microscopic examination of her renal biopsy tissues revealed sclerotic lesions such as global sclerosis or adhesions of Bowman’s capsule, and marked tubulointerstitial lesions were found. Immunofluorescent findings revealed IgA and C3 mesangial deposits. Electron microscopic examination showed slight dense deposits in the mesangial areas. Case 2: A 24-year-old man, the son of case 1 ‚ was referred to our hospital in January 1989 because of episodes of proteinuria and occult hematuria concomitant with upper respiratory tract infections. He was also diagnosed as having von Recklinghausen’s disease at the Dermatology Department of our hospital in 19 8 9. He was admitted to our hospital in September

INTERMEDIATE-DENSITY LIPOPROTEIN IS A DNA SYNTHESIS STIMULATION FACTOR IN CULTURED HUMAN MESANGIAL CELLS

Noriaki Yorioka, MD, 2nd Department of Internal Medicine, Hiroshima University School of Medicine, 1-2-3 Kasumi, Minami-ku, Hiroshima City 734 (Japan) Dear Sir, Based on the hypothesis of Moorhead et al. [1], abnormalities of the lipid metabolism are now considered aggravating factors for glomerulonephritis. Low-density lipoprotein (LDL), a cholesterol-rich lipoprotein, attracted attention, initially, and many reports appeared on LDL as a proliferation factor in cultured mesangial cells [2-4]. The presence of LDL receptors and scavenger receptors in mesangial cells has been proved [3, 4], and the uptake of LDL by mesangial cells has been confirmed using an isotopebinding method and the fluorescent antibody technique [3, 5, 6]. It is also known that mesangial cells, with incorporated LDL, secrete various chemical mediators and alter the mesangial microen-vironment [7]. For example, there are reports on the expression of messenger RNA of growth factors and cytokines such as platelet-derived growth factor [2] and macro-phage chemoattractant protein 1 [8], extracellular matrix such as fibronectin [8] and type IV collagen [9], and eicosanoids such as PG-E2 [4] from mesangial cells when stimulated with LDL or oxidized LDL. A cyto-toxic effect of oxidized LDL on mesangial cells and the mechanism of progression to glomerulosclerosis due to this cytotoxicity have been proposed [7, 10]. However, no reports have appeared, as yet, on the action of the triglyceride-rich intermediate-density lipoprotein (IDL) on the mesangial cells. Therefore, we observed the effects on DNA synthesis in mesangial cells stimulated by IDL. The method involved isolation and culture of human mesangial cells as previously 1,400 g 1,200 o 1,000 600 400 200 5 10 50 100 500 1,000 IDL (μg/ml)

CAPD CATHETER RUPTURE WITHOUT DETERIORATION

Quality assurance of platelet concentrates should include regular determinations on sampled units of platelet concentrate volume, platelet count, pH value and an indicator of maintenance of platelet discoid shape. In regard to the latter, recent investigations suggest that the visual assessment of platelet swirling may provide meaningful and reproducible information with limited staff training and efforts. Other laboratory assays provide useful data that may prove beneficial particulary when new procedures and products are examined. In addition to laboratory tests, it is of utmost importance to regularly monitor the effectiveness of platelet support therapy at clinical level. This can be done using a number of indicators including the proportion of patients who show febrile, allergic and septic reactions, who become and remain refractory to random-donor platelet support, who develop and/or die of hemorrhage not prevented or corrected by platelet support. (Int J Artif Organs 1998; 21 S-6: 95-7)

FATAL HEPATIC FAILURE CAUSED BY MILIARY TUBERCULOSIS IN A HEMODIALYSIS PATIENT : CASE REPORT

Five blood banks of Regione Lazio implemented a multicomponent collection program using apheresis technology. The automated collection of blood components included: red blood cell concentrate and fresh plasma (RBCP), plasma and platelet concentrate (P-PLT), red blood cell and platelet concentrates (RBC-PLT). 334 voluntary blood donors and 30 patients as autologous donorswere involved. Apheresis collection of RBCp, P PLT, RBC PLT yielded a standardized product (adequate volume, low residual leucocyte counts, adeguate hematocrit, low platelet contamination) was well tolerated by donors, was performed without technical problems. We conclude that multicomponent collection is a new feasible alternative to conventional whole blood collection. (tnt J Artif Organs 1998; 21 S-6: 23-5)