Aims/hypothesis. Inflammation and fibrosis are pathological mechanisms that are partially regulated by cell signalling through the p38 mitogen-activated protein kinase (MAPK) pathway. Elements of the diabetic milieu such as high glucose and advanced glycation endproducts induce activation of this pathway in renal cells. Therefore, we examined whether p38 MAPK signalling is associated with the development of human and experimental diabetic nephropathy. Methods. Immunostaining identified phosphorylated (active) p38 MAPK in human biopsies with no abnormality (n=6) and with Type 2 diabetic nephropathy (n=12). Changes in kidney levels of phosphorylated p38 were assessed by immunostaining and western blotting in mice with streptozotocin-induced Type 1 diabetes that had been killed after 0.5, 2, 3, 4 and 8 months, and in Type 2 diabetic db/db mice at 2, 4, 6 and 8 months of age. Results. Phosphorylated p38 was detected in some intrinsic cells in normal human kidney, including podocytes, cortical tubules and occasional interstitial cells. Greater numbers of these phosphorylated p38+ cells were observed in diabetic patients, and phosphorylated p38 was identified in accumulating interstitial macrophages and myofibroblasts. A similar pattern of p38 activation was observed in both mouse models of diabetes. In mice, kidney levels of phosphorylated p38 increased (2-6 fold) following the onset of Type 1 and Type 2 diabetes. In both mouse models, interstitial phosphorylated p38+ cells were associated with hyperglycaemia, increased HbA 1 c levels and albuminuria. Further assessment of streptozotocin-induced diabetic nephropathy showed that interstitial phosphorylated p38+ cells correlated with interstitial fibrosis (myofibroblasts, collagen). Conclusions/interpretation. Increased p38 MAPK signalling is a feature of human and experimental diabetic nephropathy. Time course studies in mouse models suggest that phosphorylation of p38 plays a pathological role, particularly in the development of interstitial fibrosis.

The aquaporin (AQP)-9 gene was recently isolated from human and rat liver cDNA libraries as a member of the water channel family for water and neutral solutes. Although the expression of AQP9 mRNA has been demonstrated in several organs including the liver and testis by Northern blot analysis, the cellular and subcellular localization of the AQP9 protein remains unclear. In the present light and electron microscopic immunohistochemical study, the localization of the AQP9 immunoreactivity was examined in fifteen kinds of rat organs using an antibody against rat AQP9 synthetic peptide. The antibody immunostained a major band of approximately 33 kDa in the liver by Western blot analysis. Immunoreactivity for AQP9 was found exclusively in the liver and testis among the organs examined. In the liver, positive staining appeared selectively along the space of Disse. Immunoelectron microscopy confirmed the localization of AQP9 on the surface of hepatocyte microvilli facing the space of Disse. In the testis, the plasma membrane of Leydig cells located between seminiferous tubules was conspicuously immunoreactive to the antibody. Intense mRNA expression was detected in the liver and testis but not in other organs by ribonuclease protection assay. These findings suggest a specific role for AQP9 in the transport of water and non-charged solutes in hepatocytes and Leydig cells.

These results indicate that Mo/Mphi play an important role in the induction of crescentic anti-GBM GN and glomerular injury.

Introduction: Anemia is the most common finding in chronic kidney disease patients. Iron supplements are commonly prescribed for these patients with or without erythropoietin therapy by means of oral and intravenous iron. Both oral and intravenous irons have their own advantage and disadvantage, and the efficacy is also different. The objective of the study is to analyze the efficacy of oral and intravenous iron in chronic kidney disease patients on erythropoietin therapy, an erythropoiesis stimulating agents for increment of haemoglobin. Methods: This is a prospective study comparing intravenous iron to oral iron in chronic kidney disease patients who underwent maintenance hemodialysis at different centers and visited Kathmandu Medical College Teaching Hospital from April 2010 to April 2011. Patients having a haemoglobin level of < 11 g/dl, transferrin saturation (TSAT) < 25%, ferritin < 300ng/ml and who were on erythropoietin therapy were allocated alternately into two groups to receive oral iron (iron fumarate) or IV iron (iv sucrose). Haemoglobin was measured after 30 days of therapy. Results: A significant increase in haemoglobin levels was observed in both groups. But the mean haemoglobin increment was more in the IV iron group than in the oral iron group. Sixty percent 60% of patients in the IV iron group had an increase in the haemoglobin level of more than 1gm/dl while only 20% of the oral iron group had this increase. Conclusions: Intravenous iron therapy is more effective in raising the hemoglobin level in hemodialysis dependent chronic kidney disease patients. Keywords: anemia; chronic kidney disease; iron.

Anti-glomerular basement membrane (GBM) nephritis in Sprague-Dawley (SD) rats was characterized by development of marked glomerular sclerosis and tubulointerstitial fibrosis. To elucidate sequential change of the glomerular sclerosis and tubulointerstitial fibrosis, accumulation and mRNA expression of extracellular matrix (ECM) components and transforming growth factor (TGF)-beta were examined in the glomerulus and cortex during the disease course by histology, immunostaining and ribonuclease protection assay. Mild proliferative and degenerative lesions appeared in the glomeruli by day 15 after anti-GBM antibody binding to GBM and progressed to glomerular sclerotic lesion thereafter. Conversely, interstitial change was first recognized by infiltration of mononuclear cells after day 20, followed by marked accumulation of ECM and tubular degeneration. The interstitial fibrosis was induced without apparent binding of anti-GBM antibody to tubular basement membrane. Accumulation of fibronectin, collagen type I and type IV was noted in the interstitium by immunofluorescence microscopy in association with enhanced expression of mRNA for these ECM components and their regulatory molecules such as matrix metalloproteinase (MMP2), tissue inhibitor of metalloproteinase (TIMP)-1 and TGF-beta1 both in glomeruli and cortex. The glomerular expression of these mRNA increased apparently by day 15 and reached a plateau or a peak at day 20. The expression of the same mRNA increased gradually from day 15 to day 29 in the cortex. These observations show that interstitial fibrosis follows glomerular sclerosis after anti-GBM antibody injection in SD rats, suggesting that at least a part of the mechanism for ECM accumulation in the glomerulus and interstitium is essentially the same in terms of composition of ECM and expression of its regulatory molecules.