losartan-potassium and Glomerulosclerosis--Focal-Segmental

Rituximab, a monoclonal antibody directed against the CD20 molecule found on pre-B cells and mature B cells (but not on plasma cells), was introduced in the late 1990s for the treatment of non-Hodgkin's lymphoma. Recently, this antibody has been used to treat autoimmune diseases, especially those associated with a prominent humoral component and with potentially pathogenic autoantibodies. Small cohort studies have indicated that rituximab could have an important role in the management of these disorders. Rituximab has also been utilized in the transplant setting, to diminish levels of alloreactive antibodies in highly sensitized patients, to manage ABO-incompatible transplants, and to treat rejection associated with B cells and antibodies. The exact mechanism by which rituximab exerts its effects in autoimmunity and transplantation remains unclear, as specific autoantibody or alloantibody levels often seem not to diminish in parallel with clinical improvement. A role for rituximab in depleting B cells and compromising their antigen-presenting function seems likely; rituximab might also inhibit T-cell activation. A synergistic effect has been noted in vitro following administration of corticosteroids to B-cell lines, with accentuation of B-cell cytotoxicity; this observation might be relevant to certain studies, as some regimens have utilized both agents simultaneously. This article reviews the current use of rituximab in renal disease and transplantation, and includes discussion of the drug's potential role in novel therapeutic protocols.

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Murine-Derived; Autoimmune Diseases; Autoimmunity; B-Lymphocytes; Erythropoietin; Glomerulonephritis, Membranous; Glomerulosclerosis, Focal Segmental; Graft Rejection; Humans; Immunologic Factors; Kidney Diseases; Kidney Transplantation; Lupus Erythematosus, Systemic; Lymphoproliferative Disorders; Recombinant Proteins; Red-Cell Aplasia, Pure; Rituximab; Vasculitis

Low birthweight infants have a reduced number of nephrons and are at high risk of chronic kidney disease. Preterm birth and/or intrauterine growth restriction (IUGR) may also affect peritubular capillary development, as has been shown in other organs.. We report two patients with a history of preterm birth and extremely low birthweight who showed polycythemia and renal capillary rarefaction. Patient 1 and 2, born at 25 weeks of gestation with a birthweight of 728 and 466 g, showed mild proteinuria at age 8 and 6 years, respectively. In addition to increasing proteinuria, hemoglobin levels became elevated towards adolescence and their serum erythropoietin (EPO) was high despite polycythemia. Light microscopic examination of renal biopsy specimens showed glomerular hypertrophy, focal segmental glomerulosclerosis, and only mild tubulointerstitial fibrosis. A decrease in the immunohistochemical staining of CD31 and CD34 endothelial cells in renal biopsy specimens was consistent with peritubular capillary rarefaction.. Since kidney function was almost normal and fibrosis was not severe, we consider that the capillary rarefaction and polycythemia associated with elevated EPO levels were largely attributable to preterm birth and/or IUGR.

Topics: Adolescent; Angiotensin II Type 1 Receptor Blockers; Antigens, CD34; Apgar Score; Biopsy; Child; Endothelial Cells; Erythropoietin; Female; Fibrosis; Glomerulosclerosis, Focal Segmental; Hemoglobins; Humans; Infant, Extremely Premature; Infant, Newborn; Infant, Premature, Diseases; Infant, Very Low Birth Weight; Kidney Glomerulus; Kidney Tubules; Male; Microvascular Rarefaction; Nephrons; Platelet Endothelial Cell Adhesion Molecule-1; Polycythemia; Pregnancy; Premature Birth; Proteinuria; Valsartan

Glomerulonephritis (GN) develops via accumulation of extracellular matrix through macrophage recruitment in glomeruli. It is unclear whether epoetin beta pegol (continuous erythropoietin receptor activator, CERA), a long-acting erythropoiesis-stimulating agent, exerts a renoprotective effect by preventing glomerulosclerosis. We examined the renoprotective effect of CERA in rats with Thy-1 glomerulonephritis (Thy-1-GN), an animal model for mesangial proliferative glomerulonephritis.. Thy-1-GN was induced in F344 rats by injection of anti-Thy1.1 antibody. CERA (25 µg/kg) was intravenously administered 4 h before anti-Thy1.1 antibody injection. After 6 days, blood and urine was collected for biochemical analysis and kidneys harvested for analysis of histopathology and mRNA expression.. In Thy-1-GN rats, CERA suppressed increased urinary total protein, urea nitrogen, and N-acetyl-β-(D)-glucosaminidase. CERA significantly prevented glomerulosclerosis and expression of α-smooth muscle actin, collagen-1, and fibronectin. Increased macrophage infiltration and up-regulated monocyte chemotactic protein-1 were significantly suppressed by CERA. Furthermore, CERA also suppressed up-regulation of arginase-1, a marker of M2 macrophages. Arginase-1 expression levels strongly correlated with levels of collagen-1 and fibronectin mRNA.. These results suggest that CERA has potential to protect kidney function through the prevention of glomerulosclerosis, accompanied by prevention of M2 macrophage recruitment.

Topics: Acetylglucosaminidase; Actins; Animals; Arginase; Blood Urea Nitrogen; Cell Movement; Chemokine CCL2; Collagen Type I; Disease Models, Animal; Erythropoietin; Fibronectins; Glomerulonephritis; Glomerulosclerosis, Focal Segmental; Isoantibodies; Ki-67 Antigen; Macrophages; Male; Polyethylene Glycols; Proteinuria; Rats; Rats, Inbred F344; RNA, Messenger; Tumor Necrosis Factor-alpha

Detachment or apoptosis of podocytes leads to proteinuria and glomerulosclerosis. There are no current interventions for diabetic or non-diabetic glomerular diseases specifically preventing podocyte apoptosis. Binding of erythropoiesis stimulating proteins (ESPs) to receptors on non-hematopoietic cells has been shown to have anti-apoptotic effects in vitro, in vivo, and in preliminary human studies. Recently, erythropoietin receptors were identified on podocytes; therefore, we tested effects of darbepoetin alfa in preventing podocyte apoptosis. Cultured immortalized mouse podocytes were treated with low-dose ultraviolet-C (uv-C) irradiation to induce apoptosis in the absence or presence of darbepoetin alfa. Apoptosis was quantified by Hoechst staining and by caspase 3 cleavage assessed by Western blots. Pretreatment with darbepoetin alfa significantly reduced podocyte apoptosis with this effect involving intact Janus family protein kinase-2 (JAK2) and AKT signaling pathways. Additionally, darbepoetin alfa was found protective against transforming growth factor-beta1 but not puromycin aminonucleoside induced apoptosis. Mice with anti-glomerular antibody induced glomerulonephritis had significantly less proteinuria, glomerulosclerosis, and podocyte apoptosis when treated with darbepoetin alfa. Our studies show that treatment of progressive renal diseases characterized by podocyte apoptosis with ESPs may be beneficial in slowing progression of chronic kidney disease.

Topics: Animals; Antibodies; Apoptosis; Autoantibodies; Cell Proliferation; Cells, Cultured; Darbepoetin alfa; Disease Models, Animal; Disease Progression; Erythropoietin; Glomerulonephritis; Glomerulosclerosis, Focal Segmental; Janus Kinase 2; Mice; Podocytes; Protective Agents; Proteinuria; Proto-Oncogene Proteins c-akt; Puromycin Aminonucleoside; Receptors, Erythropoietin; Signal Transduction; Transforming Growth Factor beta1; Ultraviolet Rays

We previously demonstrated that chronic hypoxia has pivotal roles in the progression of tubulointerstitial injury from the early stage of the uninephrectomized Thy1 nephritis model. We have also shown that pretreatment of cobalt confers renoprotection in the ischemia/reperfusion (I/R) injury, in association with the up-regulation of hypoxia-inducible factor (HIF)-regulated genes. Here, we tested the hypothesis that cobalt administration not only attenuates acute ischemic insult, but also ameliorates tubulointerstitial injury secondary to chronic hypoxia.. We applied sustained cobalt treatment to the uninephrectomized Thy1 nephritis model at 3 to 5 weeks, when tubular hypoxia appeared. Histologic evaluation, including glomerular and peritubular capillary networks, was made at 8 weeks. HIF activation was confirmed by real-time polymerase chain reaction (PCR) analyses for HIF-regulated genes, such as erythropoietin (EPO), vascular endothelial growth factor (VEGF), and heme oxygenase 1 (HO-1). Up-regulation of HIF-1alpha and HIF-regulated genes was also verified by Western blotting analysis. To elucidate responsible mechanisms of cobalt in the amelioration of tubuloniterstitial injury, terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL) staining was conducted at 5 weeks. A combination therapy with angiotensin receptor blocker (ARB), olmesartan, was also challenged.. Although the intervention did not change glomerular structural damage or urinary protein excretion rate, tubulointerstitial injury was improved in cobalt-treated animals when compared with the vehicle-treated group. The amelioration was associated with the parallel up-regulation of renoprotective, HIF-regulated gene expression. TUNEL staining revealed that the number of apoptotic cells was reduced in the cortex by cobalt administration, suggesting that renoprotection was achieved partly through its antiapoptotic properties. Furthermore, it was demonstrated that cobalt treatment exerts additional renoprotective effects with the ARB treatment in this model.. Maneuvers to activate HIF in the ischemic tubulointerstitium will be a new direction to future therapeutic strategies.

Topics: Animals; Antibodies; Antimutagenic Agents; Apoptosis; Capillaries; Cobalt; Erythropoietin; Gene Expression Regulation; Glomerulonephritis; Glomerulosclerosis, Focal Segmental; Heme Oxygenase-1; Hypoxia; Hypoxia-Inducible Factor 1; In Situ Nick-End Labeling; Isoantibodies; Kidney Tubules; Male; Nephrectomy; Rats; Rats, Sprague-Dawley; Renin-Angiotensin System; Reperfusion Injury; Vascular Endothelial Growth Factor A

Topics: Adult; Cardiovascular Diseases; Decision Making; Disease Progression; Epoetin Alfa; Erythropoietin; Female; Glomerulosclerosis, Focal Segmental; Hematinics; Humans; Kidney Failure, Chronic; Kidney Transplantation; Morbidity; Neoplasms; Pregnancy; Pregnancy Complications; Recombinant Proteins; Renal Dialysis; Renal Replacement Therapy; Risk Assessment; Uremia

The hematopoietic cytokine erythropoietin has cytoprotective effects in endothelial cells in vitro that are mediated through direct activation of the pro-survival Akt tyrosine kinase signaling pathway. We tested the hypothesis that low-dose therapy with the long-acting recombinant human erythropoietin analogue darbepoetin alpha protects vascular endothelium in vivo in a classic remnant kidney rat model characterized by severe endothelial damage, progressive vascular sclerosis, and ischemia-induced tissue fibrosis.. Using a parallel group study design, we randomly assigned animals after 5/6 nephrectomy to treatment with either saline (n=36) or 0.1 microg/kg body wt darbepoetin (n=24) subcutaneously once weekly. We monitored hematocrit, blood pressure, and serum creatinine regularly and obtained renal tissue 6 weeks after nephrectomy for morphological and immunohistochemical analysis. Darbepoetin-treated animals had significantly improved survival compared with saline-treated controls (63% versus 33%; P<0.05), although hematocrit levels were similar in both groups. Darbepoetin treatment ameliorated endothelial damage; attenuated the composite tissue injury score (saline 1.9+/-0.4; darbepoetin 0.4+/-0.2; P<0.001), which included vascular sclerosis, glomerulosclerosis, and tubulointerstitial damage; and preserved renal function. We found persistent activation of the pro-survival Akt signaling pathway in endothelial and epithelial glomerular cells in darbepoetin-treated animals, accompanied by a significant reduction of apoptotic cell death in renal tissue.. Low-dose darbepoetin treatment confers vascular and tissue protection that is associated with persistent stimulation of the pro-survival Akt signaling pathway. The use of recombinant human erythropoietin or analogues may have utility in preventing ischemia-related progressive vascular injury and organ failure.

Topics: Animals; Apoptosis; Darbepoetin alfa; Disease Models, Animal; Disease Progression; Drug Evaluation, Preclinical; Endothelium, Vascular; Erythropoietin; Glomerulosclerosis, Focal Segmental; Hematocrit; Hematopoietic Stem Cell Mobilization; Hypertension, Renal; Ischemia; Kidney; Life Tables; Male; Multiple Organ Failure; Nephrectomy; Nephritis, Interstitial; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Random Allocation; Rats; Rats, Sprague-Dawley; Signal Transduction

Two anephric patients in the course of one year erythropoietin therapy improved their anemic status without changes in Mean Arterial Blood Pressure. The discordant time course behaviour of hematocrit and blood pressure points to the importance of residual renal tissue for blood pressure to develop during erythropoietin therapy in the renoprival status.

Topics: Adult; Anemia; Blood Pressure; Combined Modality Therapy; Erythropoietin; Female; Glomerulosclerosis, Focal Segmental; Hematocrit; Humans; Hypertension; Kidney; Male; Nephrectomy; Polycystic Kidney Diseases; Renal Dialysis; Time Factors

A 23-year-old-man had true erythrocytosis and the nephrotic syndrome. A renal biopsy specimen showed focal sclerosing glomerulonephritis and nephrosclerosis. Both serum and urinary erythropoietin levels were increased, and plasma renin activity was in the high normal range. The association of erythrocytosis and glomerulonephritis with the nephrotic syndrome is reviewed, and the uniqueness of this association is proposed. Finally, a dissociation between these hormones was demonstrated using water immersion to the peck as a suppressive maneuver.

Topics: Adult; Biopsy; Erythropoietin; Glomerulosclerosis, Focal Segmental; Humans; Immersion; Kidney; Male; Microscopy, Electron; Nephrotic Syndrome; Polycythemia; Renin