[Advances in the treatment of progressive renal dysfunction. 5. Diabetic nephropathy].
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Biomedical subjects
Publications and source records attributed to Kenichi Shikata.
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IgA nephropathy (IgAN) is the most common form of chronic glomerulonephritis with IgA deposits present mainly in the mesangial areas. We performed a 10-year retrospective case-control study of 71 patients with IgAN to evaluate the long-term effects and prognostic factors associated with tonsillectomy. Forty-one patients (19 males and 22 females) underwent tonsillectomy (Group A) and 30 patients (13 males and 17 females) did not (Group B). These patients were followed for more than 10 years after renal biopsy. The average age at initial renal biopsy was 29.78 years in Group A and 33.0 years in Group B. The average follow-up period was 13 years and 3 months in Group A, and 12 years and 7 months in Group B. Glomerular damage demonstrated on renal biopsy was more extensive in Group A than in Group B. Prognosis after 10 years of follow-up was compared between the two groups. The clinical remission rate was 24.4% in Group A and 13.3% in Group B, the stable renal function rate was 82.9% in Group A and 70.0% in Group B, and the renal survival rate was 95.1% in Group A and 73.3% in Group B. The renal survival rate in Group A was significantly higher than that in Group B (p <0.05). Although evaluation of renal pathology based on renal biopsy was useful in predicting the long-term effects of tonsillectomy in IgAN patients, the results of tonsillar provocation tests were not.
BACKGROUND: Since adrenomedullin (AM) elicits vasodilatation by binding to specific AM receptors consisted of calcitonin-receptor-like receptor (CRLR)/receptor-activity-modifying protein 2 (RAMP2) or CRLR/receptor-activity-modifying protein 3 (RAMP3) on endothelial cells and stimulating nitric oxide production, AM possibly involves in glomerular capillary dilatation in early phase of diabetic nephropathy. METHODS: Streptozotocin (STZ)-induced diabetic Sprague-Dawley rats at 4 weeks after the injection were employed for expression studies of AM, RAPM2, and RAMP3. The measurement of AM peptide levels in kidney tissue, plasma, and urine was performed. Human aortic endothelial cells (HAEC) were used to investigate functional link between glucose-induced AM production and nitric oxide release. RESULTS: STZ rats showed glomerular hypertrophy and increased urinary NO2- and NO3- excretion. By Northern blot analyses, AM and RAPM2 mRNAs significantly increased in the kidneys of STZ rats, while RAMP3 mRNA was not altered. In STZ rats, AM peptide was actively secreted into urine (1280 +/- 360 fmol/day vs. control 110 +/- 36 fmol/day). AM peptide was mainly detected on cortical and medullary collecting duct cells in control rat kidneys and AM peptide and mRNA were up-regulated on afferent arterioles and glomeruli of STZ rats. RAMP2 expression was detected on afferent arterioles and not in glomeruli in control rats and it was up-regulated on glomerular endothelial cells in STZ rats. In HAEC culture, d-glucose stimulated AM and nitric oxide production and they were suppressed by addition of AM antisense oligodeoxynucleotides. CONCLUSION: Up-regulated expression of AM and RAMP2 in afferent arterioles and glomeruli may be related to selective dilatation of glomerular capillary in acute phase of type 1 diabetes.
Diabetes has become the most common single cause of end stage renal disease. Nephrotic syndrome is often manifested in the progression of diabetic nephropathy. Diabetic nephropathy has several pathways for development, such as glomerular hyperfiltration, upregulation of protein kinase C, advanced glycation end products, activation of polyol pathway, increased oxidative stress and upregulation of growth factors. Intensive control of blood pressure and the use of angiotensin converting enzyme inhibitor or angiotensin receptor blocker can protect the progression of nephropathy with nephrotic syndrome. However further studies are necessary for the clinical guidline in patients with diabetic nephropathy manifesting with nephrotic syndrome.
Mononuclear cells infiltrating the interstitium are involved in renal tubulointerstitial injury. The unilateral ureteral obstruction (UUO) is an established experimental model of renal interstitial inflammation. In our previous study, we postulated that L-selectin on monocytes is involved in their infiltration into the interstitium by UUO and that a sulfated glycolipid, sulfatide, is the physiological L-selectin ligand in the kidney. Here we tested the above hypothesis using sulfatide- and L-selectin-deficient mice. Sulfatide-deficient mice were generated by gene targeting of the cerebroside sulfotransferase (Cst) gene. Although the L-selectin-IgG chimera protein specifically bound to sulfatide fraction in acidic lipids from wild-type kidney, it did not show such binding in fractions of Cst(-/-) mice kidney, indicating that sulfatide is the major L-selectin-binding glycolipid in the kidney. The distribution of L-selectin ligand in wild-type mice changed after UUO; sulfatide was relocated from the distal tubules to the peritubular capillaries where monocytes infiltrate, suggesting that sulfatide relocated to the endothelium after UUO interacted with L-selectin on monocytes. In contrast, L-selectin ligand was not detected in Cst(-/-) mice irrespective of UUO treatment. Compared with wild-type mice, Cst(-/-) mice showed a considerable reduction in the number of monocytes/macrophages that infiltrated the interstitium after UUO. The number of monocytes/macrophages was also reduced to a similar extent in L-selectin(-/-) mice. Our results suggest that sulfatide is a major L-selectin-binding molecule in the kidney and that the interaction between L-selectin and sulfatide plays a critical role in monocyte infiltration into the kidney interstitium.
Leukocyte infiltration during inflammation is mediated by the sequential actions of adhesion molecules and chemokines. By using a rat ureteral obstruction model, we showed previously that L-selectin plays an important role in leukocyte infiltration into the kidney. Here we report the purification, identification, and characterization of an L-selectin-binding heparan sulfate proteoglycan (HSPG) expressed in the rat kidney. Partial amino acid sequencing and Western blotting analyses showed that the L-selectin-binding HSPG is collagen XVIII, a basement membrane HSPG. The binding of L-selectin to isolated collagen XVIII was specifically inhibited by an anti-L-selectin monoclonal antibody, EDTA, treatment of the collagen XVIII with heparitinase or heparin but not by chemically desulfated heparin. A cell binding assay showed that the L-selectin-collagen XVIII interaction mediates cell adhesion. Interestingly, collagen XVIII also interacted with a chemokine, monocyte chemoattractant protein-1, and presented it to a monocytic cell line, THP-1, which enhanced the alpha(4)beta(1) integrin-mediated binding of the THP-1 cells to vascular cell adhesion molecule-1. Thus, collagen XVIII may provide a link between selectin-mediated cell adhesion and chemokine-induced cellular activation and accelerate the progression of leukocyte infiltration in renal inflammation.
A 50-year-old woman with a 15-year history of type 2 diabetes mellitus was admitted to our hospital due to high fever and a skin lesion with severe pain, swelling and a sensation of heat in the right thigh. Laboratory examination showed elevated C-reactive protein (CRP), thrombocytopenia, nephrotic syndrome and renal dysfunction. Her blood glucose level had been well controlled. Streptococcus agalactiae was detected in both the skin lesion and blood culture, and pathological examination revealed neutrophil infiltration in the fascia and muscle layer. The patient was diagnosed with necrotizing fasciitis, septic shock and disseminated intravascular coagulation. A combination therapy of antibiotics and surgical debridement resulted in the improvement of symptoms as supported by laboratory findings, and the skin lesion also showed improvement. Although group A streptococcus is well known to be implicated in the pathogenesis of necrotizing fasciitis, only S. agalactiae, belonging to group B streptococcus, was isolated from the tissue and blood cultures in this case. Although this organism is not virulent and rarely causes a necrotizing fasciitis, both the superficial fascial layer and underlying muscle were affected in this case. There have been only a few reports of necrotizing fasciitis due to S. agalactiae in patients with diabetes mellitus. Although the blood glucose level was well controlled in our patient, this disease might be caused by other factors, including diminished sense of touch and pain, abnormality of microcirculation and hypogammaglobulinemia due to nephrotic syndrome.
A 45-year-old woman with 20-year history of diabetes mellitus was admitted to our hospital because of high fever and abdominal pain. Radical hysterectomy and bilateral pelvic lymphadenectomy had been performed 4 months before admission for invasive cervical cancer. On admission, elastic hard tumors were palpable in the lower abdomen. Laboratory examination showed positive C-reactive protein (CRP), anemia and renal dysfunction. Computed tomography (CT) revealed several lymphocysts in the pelvis. She was diagnosed with infection of pelvic lymphocysts. Since her mother also had diabetes associated with deafness, we examined mitochondrial DNA in leukocytes and detected an A to G transition at the nucleotide position of 3243 (A3243G mutation). She was diagnosed as maternally inherited diabetes mellitus and deafness (MIDD). Puncture of the cysts followed by administration of antibiotics resulted in marked improvement of symptoms and laboratory findings. This is a rare case of pelvic lymphocyst infection in a patient with a mitochondrial disorder. Although the exact mechanism of infection is not clear, MIDD may represent an unusual risk factor for infection, and further investigation is necessary to assess the influence of mitochondrial dysfunction on the immune system. Pelvic lymphocyst infection should be considered in the differential diagnosis of abdominal pain and fever in patients with MIDD after abdominal surgery.
BACKGROUND: An inflammatory process may be one of the critical factors that contribute to the development of diabetic nephropathy (DN). We reported previously that intercellular adhesion molecule-1 (ICAM-1) is up-regulated and promotes macrophage infiltration in the glomeruli of diabetic rats. 3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) have recently been emphasized to have anti-inflammatory effects; inhibition of leukocyte adhesion and migration, independent of the cholesterol-lowering effect. The present study was designed to test the hypothesis that statins prevent the development of DN by pleiotropic effects. METHODS: Streptozotocin-induced diabetic rats were treated with cerivastatin (0.5 mg/kg body weight) or vehicle for 4 weeks. We analysed glomerular macrophage infiltration and ICAM-1 expression. We also evaluated major regulators of ICAM-1, activation of nuclear factor-kappa B (NF-kappaB) using electrophoretic mobility shift assay, and oxidative stress. RESULTS: Statin treatment reduced urinary albumin excretion (UAE) (2.96+/-0.18 vs 2.38+/-0.06; log(10) UAE, P<0.05), glomerular size (12 150+/-329 vs 9963+/-307 micro m(2), P<0.05), and lowered blood pressure, compared with untreated diabetic rats. Immunohistochemistry revealed that macrophage infiltration and ICAM-1 expression in glomeruli were increased in diabetic rats and were inhibited by statin treatment. Renal NF-kappaB activity, urinary excretion and renal deposition of 8-OHdG were increased in diabetic rats, and reduced by statin treatment. CONCLUSION: Statin treatment prevented glomerular injury, independent of the cholesterol-lowering effects. Our findings suggest that the beneficial effect might be mediated by pleiotropic effects including an anti-inflammatory action through a reduction of oxidative stress, NF-kappaB activation, ICAM-1 expression and macrophage infiltration in the early phase of DN.
Diabetic nephropathy is a leading cause of end-stage renal failure. Several mechanisms, including activation of protein kinase C, advanced glycation end products, and overexpression of transforming growth factor (TGF)-beta, are believed to be involved in the pathogenesis of diabetic nephropathy. However, the significance of inflammatory processes in the pathogenesis of diabetic microvascular complications is poorly understood. Accumulation of macrophages and overexpression of leukocyte adhesion molecules and chemokines are prominent in diabetic human kidney tissues. We previously demonstrated that intercellular adhesion molecule (ICAM)-1 mediates macrophage infiltration into the diabetic kidney. In the present study, to investigate the role of ICAM-1 in diabetic nephropathy, we induced diabetes in ICAM-1-deficient (ICAM-1(-/-)) mice and ICAM-1(+/+) mice with streptozotocin and examined the renal pathology over a period of 6 months. The infiltration of macrophages was markedly suppressed in diabetic ICAM-1(-/-) mice compared with that of ICAM-1(+/+) mice. Urinary albumin excretion, glomerular hypertrophy, and mesangial matrix expansion were significantly lower in diabetic ICAM-1(-/-) mice than in diabetic ICAM-1(+/+) mice. Moreover, expressions of TGF-beta and type IV collagen in glomeruli were also suppressed in diabetic ICAM-1(-/-) mice. These results suggest that ICAM-1 is critically involved in the pathogenesis of diabetic nephropathy.
The initial event in the process of leukocyte infiltration is characterized by leukocyte rolling on the surface of the endothelium, which is mediated by selectins. P- and L-selectin bind to the sulphated sugar chains of their natural ligands, including sulphated glycolipids such as sulphatide. Recently, it has been demonstrated that sulphated glycolipids and sulphated oligosaccharides interfere with selectin binding pathways. This study synthesized sulphated hyaluronic acid (SHA), which is a potential selectin-blocking agent, and examined its therapeutic effect on the experimental progressive mesangial proliferative glomerulonephritis induced by anti-Thy-1 monoclonal antibody (1-22-3 MAb) after unilateral nephrectomy. The selectin-inhibitory effect of SHA in vitro was confirmed. SHA inhibited the binding of P- and L-selectin to sulphatide, which is a glycolipid ligand for P- and L-selectin, at a concentration of 1.5 micro g/ml and 100 micro g/ml. Immunohistochemical examination showed that P-selectin was up-regulated in the glomeruli in the 1-22-3 MAb nephritis model, while the ligands for L-selectin were not detected in the glomerular tufts. A single administration of SHA ameliorated proteinuria and glomerular leukocyte infiltration in 24 h after the injection of anti-Thy-1 MAb. Anti-P-selectin MAb, but not anti-L-selectin MAb, inhibited proteinuria and glomerular leukocyte infiltration. To examine further the therapeutic effect of SHA on chronic glomerulonephritis, SHA was administered daily from day 3 to day 14 in this model. Proteinuria and glomerular leukocyte infiltration were significantly diminished in SHA-treated rats on day 14. These results suggest that SHA ameliorated rat progressive mesangial proliferative glomerulonephritis by inhibiting P-selectin-dependent leukocyte infiltration in glomeruli. Sulphated oligosaccharides may be beneficial for the therapy of mesangial proliferative glomerulonephritis.
Stable prostacyclin analogue, beraprost sodium (BPS) has recently been reported to attenuate glomerular hyperfiltration in diabetic rats, however, the mechanism has been still unknown. We previously reported that overexpression of endothelial cell nitric oxide synthase (ecNOS) in afferent arterioles and glomeruli induce inappropriate dilatation of afferent arterioles and glomerular hyperfiltration through overproduction of nitric oxide in early stage of diabetic nephropathy. In this study, we tested the hypothesis that BPS ameliorates glomerular hyperfiltration through modulating ecNOS expression in diabetic nephropathy. Furthermore, we examined the effects of BPS on the expression of intercellular adhesion molecule-1 (ICAM-1) and macrophage infiltration in diabetic glomeruli, because glomerular hyperfiltration induces the expression of ICAM-1 resulting in macrophage infiltration. Male Sprague-Dawley (SD) rats were administered continuously with BPS for 4 weeks after induction of diabetes by streptozotocin. In diabetic rats, the diameters of afferent arterioles, glomerular volume, creatinine clearance and urinary excretion of albumin and NO2/NO3 were increased as compared with non-diabetic control rats. Treatment with BPS improved these changes. The expression of ecNOS was increased in afferent arterioles and glomeruli in diabetic rats and suppressed by BPS. Prostacyclin receptor was expressed along afferent arterioles. Our results suggest that BPS attenuates glomerular hyperfiltration by modulating ecNOS expression in early stage of diabetic nephropathy. Moreover, BPS may inhibit ICAM-1-dependent infiltration of macrophages in diabetic glomeruli.
A 62-year-old Japanese man presented with high fever, cough, and sputa. Computed tomography (CT) scan of the chest revealed lung infiltrates with air bronchogram of the right middle lobe and mediastinal lymphadenopathy. Bronchoscopic examination was performed, and Mycobacterium avium complex was detected from bronchoalveolar lavage fluid. Although the administration of clarithromycin and levofloxacin improved the patient's symptoms, the lung infiltrates on chest CT scan gradually worsened. Lung biopsy of segments 4 and 8 by video-assisted thorachoscopy revealed angiocentric and angiodestructive massive lymphoplasmocytic infiltrations with multinucleated giant cells, which were compatible with grade II angiocentric immunoproliferative lesions. The patient was found to have deterioration of renal function, and glomerular filtration rate was 32.6 mL/min. His kidneys were enlarged and showed prominent and diffuse uptake of gallium-67 citrate. Percutaneous renal biopsy revealed massive infiltration of CD4+ mononuclear cells, plasma cells, and eosinophils in the interstitium and destruction of normal structure of tubules. Blood vessels were destroyed and replaced by inflammatory cells. The combination chemotherapy achieved a remission, and the patient has remained free of disease at 2 years after onset of the illness. We recommend the imaging of kidneys for diagnosis and following renal biopsy to evaluate the renal involvement of angiocentric immunoproliferative lesions.
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BACKGROUND: Nitric oxide (NO) plays important roles in a variety of pathophysiological processes. It has been reported that inducible NO synthase (iNOS) is upregulated in the glomeruli of patients with glomerulonephritis, although there has been no direct evidence that NO generated by iNOS contributes to the progression of glomerulonephritis. ONO-1714, a novel cyclic amidine analog, is a selective inhibitor of iNOS. To elucidate the role of iNOS in the pathogenesis of experimental crescentic glomerulonephritis, we examined the effect of ONO-1714 given to rats with nephrotoxic serum (NTS) nephritis. METHODS: We induced NTS nephritis in Wistar-Kyoto (WKY) rats. These rats were given ONO-1714 or physiological saline intraperitoneally for 14 days using an osmotic pump after intraperitoneal injection with NTS. RESULTS: Glomerular expression of iNOS and urinary excretion of NO metabolites (nitrite/nitrate) were increased in rats after injection of NTS. As compared with the control group, ONO-1714 significantly reduced proteinuria, crescent formation, glomerular infiltration of macrophages and urinary excretion of nitrite/nitrate. CONCLUSION: The present results suggest that NO radicals generated by iNOS contribute to the progression of experimental crescentic glomerulonephritis in WKY rats. The selective iNOS inhibitor ONO-1714 may be beneficial for the treatment of crescentic glomerulonephritis.