Intravenous iron therapy without rhEPO substantially reduced NT-proBNP and inflammatory status in anemic patients with CHF and moderate CRF. This situation was associated with an improvement in LVEF, NYHA functional class, exercise capacity, renal function, and better quality of life.
Before the introduction of erythropoiesis-stimulating agents (ESAs) in 1989, repeated transfusions given to patients with end-stage renal disease caused iron overload, and the need for supplemental iron was rare. However, with the widespread introduction of ESAs, it was recognized that supplemental iron was necessary to optimize hemoglobin response and allow reduction of the ESA dose for economic reasons and recent concerns about ESA safety. Iron supplementation was also found to be more efficacious via intravenous compared to oral administration, and the use of intravenous iron has escalated in recent years. The safety of various iron compounds has been of theoretical concern due to their potential to induce iron overload, oxidative stress, hypersensitivity reactions, and a permissive environment for infectious processes. Therefore, an expert group was convened to assess the benefits and risks of parenteral iron, and to provide strategies for its optimal use while mitigating the risk for acute reactions and other adverse effects.
Abstract-Oxidative stress is involved in both the pathogenesis and complications of diabetes. ACE inhibitors can slow the progression of cardiac and renal impairments related to diabetes. The effect of enalapril treatment on oxidative stress and tissue injury was studied in hearts, kidneys, and livers from streptozotocin-induced diabetic rats. Twenty-four rats were divided into the following groups: streptozotocin (65 mg/kg, single intraperitoneal dose), streptozotocinϩenalapril (20 mg enalapril/L drinking water), and control (intraperitoneal saline). Seven months after streptozotocin injection, organs were studied by light microscopy and collagen III immunolabeling. Tissue lesions and collagen labeling were graded by a semiquantitative score (0 to 4). Total glutathione content, glutathione redox status (reduced/oxidized glutathione), antioxidant enzyme activities, protein-associated sulfhydryls, thiobarbituric acid-reactive substances, and fluorescent chromolipids were determined in tissue homogenates. Glycemia was higher in both the streptozotocin and streptozotocinϩenalapril groups relative to the control group. In the streptozotocin group, creatinine clearance and body weight were lower, and systolic blood pressure and urinary albumin excretion were higher than in the streptozotocinϩenalapril and control groups. Heart, kidney, and liver lesion/labeling scores were significantly higher in the streptozotocin group compared with the streptozotocinϩenalapril and control groups. Kidney and liver total glutathione was lower in the streptozotocin group relative to the control group (PϽ0.05). Enalapril treatment significantly attenuated the reduction of total glutathione. In the heart, kidney, and liver, both glutathione and proteins were relatively more oxidized in the streptozotocin group relative to the control group (PϽ0.05). Protein and glutathione oxidation were attenuated in the streptozotocinϩenalapril group in the 3 tissues studied (PϽ0.05). Enalapril treatment attenuated the oxidation of lipids in the heart and kidney (PϽ0.05). Tissue fibrosis scores were inversely correlated with (1) both total glutathione and reduced/oxidized glutathione in heart, kidney, and liver and (2) glutathione reductase activity in the kidney. These results suggest that in streptozotocin-induced diabetic rats, the protective action of enalapril might be mediated, at least in part, by its effect on tissue oxidant/antioxidant status.
Inserra. Renal mitochondrial dysfunction in spontaneously hypertensive rats is attenuated by losartan but not by amlodipine. Am J Physiol Regul Integr Comp Physiol 290: R1616 -R1625, 2006. First published January 12, 2006 doi:10.1152/ajpregu.00615.2005.-Mitochondrial dysfunction is associated with cardiovascular damage; however, data on a possible association with kidney damage are scarce. Here, we aimed at investigating whether 1) kidney impairment is related to mitochondrial dysfunction; and 2) ANG II blockade, compared with Ca 2ϩ channel blockade, can reverse potential mitochondrial changes in hypertension. Eight-week-old male spontaneously hypertensive rats (SHR) received water containing losartan (40 mg ⅐ kg Ϫ1 ⅐ day Ϫ1 , SHRϩLos), amlodipine (3 mg ⅐ kg Ϫ1 ⅐ day Ϫ1 , SHRϩAmlo), or no additions (SHR) for 6 mo. Wistar-Kyoto rats (WKY) were normotensive controls. Glomerular and tubulointerstitial damage, systolic blood pressure, and proteinuria were higher, and creatinine clearance was lower in SHR vs. SHRϩLos and WKY. In SHRϩAmlo, blood pressure was similar to WKY, kidney function was similar to SHR, and renal lesions were lower than in SHR, but higher than in SHRϩLos. In kidney mitochondria from SHR and SHRϩAmlo, membrane potential, nitric oxide synthase, manganese-superoxide dismutase and cytochrome oxidase activities, and uncoupling protein-2 content were lower than in SHRϩLos and WKY. In SHR and SHRϩAmlo, mitochondrial H 2O2 production was higher than in SHRϩLos and WKY. Renal glutathione content was lower in SHRϩAmlo relative to SHR, SHRϩLos, and WKY. In SHR and SHRϩAmlo, glutathione was relatively more oxidized than in SHRϩLos and WKY. Tubulointerstitial ␣-smooth muscle actin labeling was inversely related to manganese-superoxide dismutase activity and uncoupling protein-2 content. These findings suggest that oxidant stress is associated with renal mitochondrial dysfunction in SHR. The mitochondrial-antioxidant actions of losartan may be an additional or alternative way to explain some of the beneficial effects of AT 1-receptor antagonists. kidney disease; nitric oxide; mitochondria; oxidative stress; hypertension ARTERIAL HYPERTENSION IS ONE of the main causes of end-stage renal failure and is also an important risk factor for the progression of glomerular and tubulointerstitial diseases to chronic renal failure (31).The pathogenesis of renal damage from hypertension is incompletely understood. A possible explanation is an increased production of oxidants in the vasculature (2, 30) and the kidney (56), a well-documented finding in experimental and clinical hypertension. However, the pathways that lead from oxidant-induced damage to cellular function decay are poorly identified.Mitochondria are energy producing organelles that also conduct other key cellular tasks. They are involved in the regulation of tissue oxygen gradients (54), the modulation of apoptosis (9), and H 2 O 2 signaling (6). Hence, mitochondrial damage may lead to the impairment of various aspects of tissue functioning.Hypertension is...
Iron sucrose (Venofer; reference) has a good safety record and is prescribed in patients with anaemia and chronic kidney disease worldwide, but various iron sucrose similar (ISS) preparations are now utilized in clinical practice. This study evaluates possible differences between iron sucrose and ISS preparations on haemodynamic and oxidative stress markers in normal rats. 60 male and 60 female Sprague Dawley rats were divided into four groups and assigned to receive commercially available ISS test 1, ISS test 2, reference or isotonic saline solution (control). A single i.v. dose of iron (40 mg/kg) or saline (equivalent volume) was administered after 24 h and every 7 days for 4 weeks. Blood samples were collected for biological assessment of haemoglobin (Hb), serum iron and percentage transferrin saturation (TSAT), and urine samples were collected to investigate creatinine clearance and proteinuria. Animals were sacrificed after receiving an i.v. dose on days 1, 7 and 28, and kidney, liver, and heart homogenates were then collected to determine antioxidant enzyme levels. Tissues were processed using Prussian blue and immmunohistochemistry techniques to identify iron deposits, tissue ferritin and pro-inflammatory markers. Systolic blood pressure was significantly reduced in the ISS groups relative to the reference and control groups after 24 h and on days 7, 14 and 21 (p < 0.05). Creatinine clearance was reduced (p < 0.01) and proteinuria marked (p < 0.01) in the ISS groups at 24 h and on days 7 and 28 relative to the reference and control groups which did not differ throughout the study. Liver enzymes were also increased in the ISS groups at 24 h and on days 7 and 28. Both ISS test 1 and ISS test 2 groups presented a significant increase in catalase, thiobarbituric reactive species, Cu, Zn-superoxide dismutase (CuZnSOD) and glutathione peroxidase activity, and a decrease in glutathione levels (p < 0.01) in the liver, heart and kidney at 24 h and on day 7 relative to the reference and control groups. Serum iron and percentage TSAT were elevated in all groups (except control) (p < 0.01) but no differences in Hb concentration were observed between them. Finally, levels of the proinflammatory markers TNF-alpha and IL6 were significantly elevated in the ISS groups (liver, heart and kidney) compared with the reference and control groups on day 28 (p < 0.01). These findings suggest significant differences between the reference and ISS test 1/ISS test 2 regarding oxidative stress and the inflammatory responses of liver, heart and kidneys in normal rats. A possible explanation for these observations could be the stability of the iron complex.
One of the most difficult management issues in lupus nephritis (LN) is the optimal duration of maintenance immunosuppression after patients are in clinical remission. Most patients receive immunosuppression for years, based mainly on expert opinion. Prospective data are unavailable. Complicating this issue are data that patients in clinical remission can still have histologically active LN; however, the implications of this are unknown. To study this, the Lupus Flares and Histological Renal Activity at the end of Treatment study (ClinicalTrial.gov, NCT02313974) was designed to examine whether residual histologic activity predisposes to LN flares in class III and IV LN. Patients in complete clinical remission for at least 12 months who had received at least 36 months of immunosuppression were eligible. Patients consented to a second kidney biopsy, were tapered off maintenance immunosuppression and were then followed prospectively for LN flares over 24 months. Forty-four patients were enrolled, and 36 completed the study. LN flares occurred in 11 patients, and ten of these had residual histologic activity on the second biopsy. All patients with an NIH activity index over two flared. The activity index and duration of systemic lupus erythematosus at the second biopsy were independent predictors of flare. A predictive equation based on these variables discriminated between flare and no flare with a sensitivity of 100%, specificity of 88%, and a misclassification rate of 8.3%. Thus, a repeat kidney biopsy may be useful in managing maintenance immunosuppression in LN, and patients in histologic remission may be candidates for withdrawal of therapy.
The kidney is an important source of angiotensin-converting enzyme (ACE) in many species, including humans. However, the specific effects of local ACE on renal function and, by extension, BP control are not completely understood. We previously showed that mice lacking renal ACE, are resistant to the hypertension induced by angiotensin II infusion. Here, we examined the responses of these mice to the low-systemic angiotensin II hypertensive model of nitric oxide synthesis inhibition with L-NAME. In contrast to wild-type mice, mice without renal ACE did not develop hypertension, had lower renal angiotensin II levels, and enhanced natriuresis in response to L-NAME. During L-NAME treatment, the absence of renal ACE was associated with blunted GFR responses; greater reductions in abundance of proximal tubule Na + /H + exchanger 3, Na + /Pi co-transporter 2, phosphorylated Na + /K + /Cl 2 cotransporter, and phosphorylated Na + /Cl 2 cotransporter; and greater reductions in abundance and processing of the g isoform of the epithelial Na + channel. In summary, the presence of ACE in renal tissue facilitates angiotensin II accumulation, GFR reductions, and changes in the expression levels and post-translational modification of sodium transporters that are obligatory for sodium retention and hypertension in response to nitric oxide synthesis inhibition.
Objective: Non‐alcoholic steatohepatitis (NASH), which is a common liver disease in industrialized countries, is associated with obesity, hypertension, and type‐2 diabetes (metabolic syndrome). Since angiotensin II (ANG II) has been suggested to play an important role in liver inflammation and fibrosis, the purpose of this study was to investigate whether therapy against renin‐angiotensin system (RAS) may provide some beneficial effect in liver of an animal model of metabolic syndrome. Methods and Procedures: For 6 months, obese Zucker rats (OZRs) were treated as follows: OZR‐group, OZR + Perindopril (P) group, OZR + Irbesartan (IRB) group, OZR + Amlodipine (AML) group, and lean Zucker rats (LZRs) group as a control. Livers were evaluated by immunohistochemistry techniques using corresponding antibodies. Results: All treated groups showed a similar reduction in blood pressure compared to untreated OZR. Therapy either with IRB or P improves insulin sensitivity and reduces hepatic enzyme level with respect to untreated OZR. Conversely, AML failed to modify both parameters. Untreated OZR displayed higher hepatic ANG II levels and steatosis together with a marked increase in tumor necrosis factor‐α (TNF‐α), interleukin‐6 (IL‐6) and transforming growth factor‐β1 (TGF‐β1) level compared to LZR. Following RAS inhibition either by P or IRB, a significant reduction (P < 0.01) in the immunostaining of TNF‐α, IL‐6 and TGF‐β1 compared to untreated OZR was observed. Discussion: These results indicate that ANG II expression is increased in the liver of these animals with steatohepatitis. Furthermore, RAS control by either angiotensin‐converting enzyme inhibition or AT1 receptor blockade seems to provide a beneficial modulation concerning the inflammatory response to liver injury in this model. Consequently, blockade of RAS could be a new approach to prevent or to treat patients with NASH.
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