Takao Kuramoto

Expression of intercellular adhesion molecule-1 and infiltration of lymphocytes in glomeruli of patients with IgA nephropathy

Using immunofluorescence, we studied 19 patients with IgA nephropathy to determine whether the expression of intercellular adhesion molecule (ICAM)-1 in glomeruli might reflect the disease activity. The relationship between the expression of ICAM-1 and the infiltration of lymphocytes, monocytes and polymorphonuclear leukocytes (PMN) in glomeruli of IgA nephropathy cases was examined. The expression of ICAM-1 in patients in the advanced stage was significantly higher than that in patients in the mild stage. In double immunofluorescence, the distribution of ICAM-1 expression in glomeruli was different from that of IgA deposition in patients in both stages. Glomeruli which showed increases of ICAM-1 expression had marked infiltration of lymphocytes (OKT4+, OKT8+ T cells), and monocytes (OKM1+ cells). Increase of urinary protein and decreases in renal function were observed in patients in the advanced stage. It appears that the expression of ICAM-1 is closely linked to glomerular cell proliferation, and infiltration of lymphocytes and monocytes in patients with IgA nephropathy. However, the expression of ICAM-1 in glomeruli might not be correlated with IgA-dominant immune complexes in this disease.

Significance of urinary type IV collagen in patients with diabetic nephropathy using a highly sensitive one‐step sandwich enzyme immunoassay

Urinary concentrations of type IV collagen in patients with diabetic nephropathy were measured by a highly sensitive, one‐step sandwich enzyme immunoassay. Samples from 298 patients with non‐insulin‐dependent diabetes mellitus (NIDDM) and 80 healthy controls were examined. In diabetic patients with macroalbuminuria or renal insufficiency, the concentrations of urinary type IV collagen were significantly higher than those of diabetic patients with normoalbuminuria or healthy controls (P < 0.001). Urinary type IV collagen concentration in diabetic patients with microalbuminuria was significantly higher than that in diabetic patients with normoalbuminuria or that in healthy controls (P < 0.001). In contrast, there were no significant changes in the concentration of serum type IV collagen between microalbuminuric patients and normoalbuminuric patients. The area under the receiver operating characteristic (ROD) curve for the urinary type IV collagen concentration was equivalent to that of urinary albumin. It was concluded that urinary type IV collagen concentration determined using this method might be a useful marker for the early detection of diabetic nephropathy. J. Clin. Lab. Anal. 11:110–116.

Measurement of soluble thrombomodulin in sera from various clinical stages of diabetic nephropathy

The levels of soluble thrombomodulin (TM) in serum samples were measured by one‐step sandwich enzyme immunoassay. The aim of the present study was to determine if levels of soluble TM in sera might correlate with disease activity in patients with diabetic nephropathy. Three hundred and twenty patients with diabetic nephropathy were examined. Patients with diabetic retinopathy were excluded from the present study.

IgA Deposits Might Not Influence the Production of Extracellular Matrix in Glomeruli of ddY Mice, a Spontaneous Animal Model for IgA Nephropathy

Immunofluorescence studies were carried out to determine whether the expression of extracellular matrix (ECM) in glomeruli of ddY mice, a model for IgA nephropathy (Bergers disease), is influenced by treatment with a rat monoclonal antibody to murine CD4 molecules (mAb CD4). This mAb CD4 showed a selective decrease in the number of CD4+ T cells in the peripheral blood of ddY mice as described previously. The ddY mice were initially treated with intravenous injections, followed by weekly intraperitoneal injections of mAb CD4. In immunofluorescence, the mean intensity of IgA deposits in the renal glomerular mesangial areas and capillary walls of the treated ddY mice was significantly lower than that in saline-treated control mice at comparable ages. There was no significant difference in the distribution or intensity of ECM components, i.e. type IV collagen, fibronectin and heparan sulfate proteoglycan, in glomeruli between the mAB CD4-treated and the control ddY mice. In light microscopy, mesangial expansion in the treated ddY mice was milder than that found in the saline control mice. No significant differences in the average number of intraglomerular cells, levels of serum IgA and urinary protein between the treated and control ddY mice were observed. Thus, it appears that although CD4+ T cells modulate the amounts of glomerular IgA deposits, other factors may be involved in the expression of ECM in glomeruli of IgA nephropathy in ddY mice.

Detection of Glycosylated Protein in Renal Tissues and Dermal Vascular Vessels in the Microalbuminuric Stage of Diabetic Nephropathy Using the Nitro Blue Tetrazolium Reaction

Detection of glycosylated protein in renal and dermal tissues was performed in patients in the microalbuminuric stage of diabetic nephropathy using the nitro blue tetrazolium (NBT) reaction. The intensity of NBT staining in glomeruli and dermal vascular vessels was marked in the microalbuminuric stage as well as in the overtly proteinuric stage. The NBT staining in the renal and dermal vascular walls in both stages was significantly stronger than in the samples of control autopsy patients. It appeared that nonenzymatic glycosylation in various tissues, i.e. kidneys and dermal vascular vessels, had already progressed in the microalbuminuric stage in patients with diabetic nephropathy.

Effect of low-protein diet on glomerular changes in ddY mice: a spontaneous animal model of IgA nephropathy.

Yasuhiko Tomino, MD, Division of Nephrology, Department of Medicine, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo 113 (Japan) Dear Sir, Long-term dietary protein restriction is generally considered to reduce the levels of urinary protein and ameliorate the glomerular injuries in patients with various glomeru-lonephritides. We usually start dietary protein restriction after the definite diagnosis, although restriction from an early stage might show a good prognosis in such diseases. The authors reported that the ddY mouse strain can serve as a spontaneous animal model for IgA nephropathy [1, 2]. Marked depositions of IgA and C3 in glo-meruli and glomerular mesangial expansion were observed in the ddY mice after 40 weeks of age [1]. We attempted to compare the glomerular changes between the low-protein and the high-protein diets in ddY mice. Twenty ddY mice were fed a standard diet containing 22% protein until 40 weeks of age. These ddY mice were divided into two diet groups, i.e. low protein (6%) and high protein (50%). ddY mice of both groups were sacrificed at 70 weeks of age. Urinary protein was measured every 2 weeks according to the method of Knight et al. [3]. Renal sections stained with hematoxylin and eosin, and periodic acid-Schiff were examined by light microscopy. Renal cryostat sections were stained with FITClabelled goat anti-mouse IgA, IgG, IgM and C3 antisera at room temperature for 45 min. Type IV and I collagens, ñbronectin and laminin were also stained. The sections were examined using a Fig. 1. a Glomerular enlargement and mesangial expansion were observed in the high-protein diet ddY mouse. PAS. × 400. b These light-microscopic findings were improved in the lowprotein diet mouse. PAS. × 400. c Glomerular deposition of IgA was marked in the high-protein diet ddY mouse. × 400. d The intensity of glomerular IgA deposition was decreased in the lowprotein diet mouse. × 400. KAIIGER E-Mail karger@karger.ch Fax+ 41 61 306 12 34

Effect of Acarbose on Blood Glucose and Proteinuria in Patients with Diabetic Nephropathy

Accessible online at: www.karger.com/journals/nef Dear Sir, A study of the effect of Acarbose on decreases in the levels of fasting blood glucose and urinary protein excretion in patients with diabetic nephropathy is described. The importance of strict control of hyperglycemia in diabetes mellitus is now well accepted. Acarbose (·-glucosidase inhibitor), a complex oligosaccharide, is a potent competitive inhibitor of sucrase and decreases postprandial hyperglycemia when administered with food [1, 2]. Lee [3] reported that glomerular mesangial thickening and mesangial immunoglobulin deposition were significantly reduced in ab/ab mice receiving highdose Acarbose (40 mg/100 g food). We recently determined the levels of fasting blood glucose, glycohemoglobin A1c (HbA1c) and urinary protein excretion after treatment with Acarbose (Glucobay®) for 24 months in diabetic patients with or without nephropathy. Non-insulin-dependent diabetes mellitus type 2 was diagnosed according to the criteria of the 75-gram oral glucose tolerance test of the Japanese Diabetic Research Council [4]. Blood and urine samples were obtained from 33 diabetic patients with or without nephropathy in our outpatient clinic. Thirteen patients who showed more than 300 mg of urinary albumin per gram creatinine (Cr) were included in this study. Levels of fasting glucose and HbA1c in the peripheral blood were measured by ordinary laboratory examination before and 24 months after initiation of the treatment. Oral doses of 150–300 mg/day of Acarbose (Glucobay) were administered for 24 months. Levels of fasting glucose 24 months after initiation of treatment with Acarbose (152 B 44 mg/dl; mean B SD) were significantly lower than those before treatment (212 B 96 mg/dl; p ! 0.001). The levels of HbA1c 24 months after initiation of treatment (7.7 B 0.9%) were also significantly lower than those before treatment (9.8 B 2.6%; p ! 0.001). The mean levels of urinary protein excretion 24 months after initiation (400 mg/g Cr) were lower than those before the treatment (540 mg/g Cr), but the difference was not statistically significant. It appears that mild glycemic control, rather than strict control, might not improve proteinuria in patients with diabetic nephropathy. It is necessary to decrease markedly the levels of blood glucose to improve proteinuria and vice versa. References

Significance of Levels of Circulating IgA-Class Immune Complex in Discriminant Analysis of Patients with IgA Nephropathy before Renal Biopsy

Discriminant analysis of clinical markers including circulating IgA-class immune complex (IgA-CIC) before renal biopsy in patients with IgA nephropathy is described. Fifty-six patients with IgA nephropathy (IgA nephropathy group) and 54 patients with other primary chronic glomerulonephritis (non-IgA nephropathy group) were examined. Discriminant analysis was applied to separate these two groups by using 21 clinical markers including levels of IgA-CIC. The levels of IgA-CIC in sera were measured by a solid-phase anti-C3 Facb enzyme immunoassay (EIA). Among these clinical markers, the levels of serum IgA, IgA-CIC and creatinine, and the degree of microhematuria in the IgA nephropathy group were significantly higher than those in the non-IgA nephropathy group. Contributions of IgA and IgA-CIC to the classification were very high and both had almost the same effect. The correct classification rate was 80.00% using five clinical markers: serum IgA, microhematuria, IgA-CIC, serum creatinine, and blood urea nitrogen. It was shown that the levels of serum IgA and IgA-CIC were major markers for the clinical diagnosis of patients with IgA nephropathy. It was concluded that discriminant analysis before renal biopsy was useful for the diagnosis of IgA nephropathy.