Iron and oxidative stress in renal insufficiency

Animal models of kidney iron overload and ferroptosis: a review of the literature

In recent years, it has been identified that excess iron contributes to the development of various pathologies and their complications. Kidney diseases do not escape the toxic effects of iron, and ferroptosis is identified as a pathophysiological mechanism that could be a therapeutic target to avoid damage or progression of kidney disease. Ferroptosis is cell death associated with iron-dependent oxidative stress. To study the effects of iron overload (IOL) in the kidney, numerous animal models have been developed. The methodological differences between these models should reflect the IOL-generating mechanisms associated with human IOL diseases. A careful choice of animal model should be considered for translational purposes.

The Effect of Iron Deficiency Anemia and Different Treatment Methods on DNA Damage: 8-hydroxy-2-deoxyguanosine Level

Ionic iron causes damages at the cellular level by forming free radicals. Reactive oxygen species lead to the formation of oxidative base damages in DNA. Among these forms the most common one and the one which has the best known mutagenity is 8-hydroxy-2′-deoxyguanosine (8-OHdG). We aimed to determine iron deficiency anemia (IDA) and its different forms of treatments; probable oxidative damage on DNA by looking at the level of 8-OHdG. The patients were divided into 4 subgroups: Oral treatment (p.o.) group; Intramuscular treatment (i.m.) group; Intravenous treatment (i.v.) group; Healthy control group. Blood and urine samples were taken from all patients totally 4 times. 8-OHdG levels detected in blood and urine samples were compared with the control group. IDA and the treatment of it affect the level of 8-OHdG. p.o. therapy should be the top priority on children.

Chronic Kidney Disease as Oxidative Stress- and Inflammatory-Mediated Cardiovascular Disease

Generating reactive oxygen species (ROS) is necessary for both physiology and pathology. An imbalance between endogenous oxidants and antioxidants causes oxidative stress, contributing to vascular dysfunction. The ROS-induced activation of transcription factors and proinflammatory genes increases inflammation. This phenomenon is of crucial importance in patients with chronic kidney disease (CKD), because atherosclerosis is one of the critical factors of their cardiovascular disease (CVD) and increased mortality. The effect of ROS disrupts the excretory function of each section of the nephron. It prevents the maintenance of intra-systemic homeostasis and leads to the accumulation of metabolic products. Renal regulatory mechanisms, such as tubular glomerular feedback, myogenic reflex in the supplying arteriole, and the renin-angiotensin-aldosterone system, are also affected. It makes it impossible for the kidney to compensate for water-electrolyte and acid-base disturbances, which progress further in the mechanism of positive feedback, leading to a further intensification of oxidative stress. As a result, the progression of CKD is observed, with a spectrum of complications such as malnutrition, calcium phosphate abnormalities, atherosclerosis, and anemia. This review aimed to show the role of oxidative stress and inflammation in renal impairment, with a particular emphasis on its influence on the most common disturbances that accompany CKD.

Earlier Detection of Glomerular Dysfunction in β-Thalassemia Major Patients

Chronic transfusions program in β-thalassemia patients will inevitably lead to iron overload with a significant morbidity and mortality. Glomerular filtration rate (GFR) is progressively declined in relation to iron overload as well as chronic anemia. Objective is to define levels of Cystatin C in transfusion dependent β-thalassemia major patients as a sensitive marker for detection of earlier glomerular dysfunction in addition to understand the effect of iron overload, chelating therapy and hepatitis infection. A cross sectional study conducted at Al-Basrah Hemoglobinopathy Centre for the period from September 2017 to January 2018 to enroll 75 β-thalassemia major patients. Data collected included duration of the disease, total transfusion requirement, details of chelation therapy and its therapeutic index. In addition to blood urea, serum creatinine and Cystatin C with estimated GFR (eGFR). The mean Cystatin C was 1.075 mg/L where 66.6% of patients had abnormal renal function which is higher proportion than those with renal (42.6%) detected according to serum creatinine level Cystatin C was significantly higher in patients who received desferrioxamine as compared to those received deferasirox (p = 0.007), in accordance with GFR which is significantly higher in patients receiving the latter chelation therapy (p = 0.009). A significant inverse relationship between Cystatin C, and GFR, while positive relationship between ferritin and Cystatin C (p = 0.0001, 0.001 respectively). Cyctatin C is better for detection and monitoring of glomerular dysfunction in B thalassemia major patient which is already not uncommon complications for the disease and iron chelation therapy.

Change in iron metabolism in rats after renal ischemia/reperfusion injury

Previous studies have indicated that hepcidin, which can regulate iron efflux by binding to ferroportin-1 (FPN1) and inducing its internalization and degradation, acts as the critical factor in the regulation of iron metabolism. However, it is unknown whether hepcidin is involved in acute renal ischemia/reperfusion injury (IRI). In this study, an IRI rat model was established via right renal excision and blood interruption for 45 min in the left kidney, and iron metabolism indexes were examined to investigate the change in iron metabolism and to analyze the role of hepcidin during IRI. From 1 to 24 h after renal reperfusion, serum creatinine and blood urea nitrogen were found to be time-dependently increased with different degrees of kidney injury. Regular variations in iron metabolism indexes in the blood and kidneys were observed in renal IRI. Renal iron content, serum iron and serum ferritin increased early after reperfusion and then declined. Hepcidin expression in the liver significantly increased early after reperfusion, and its serum concentration increased beginning at 8 h after reperfusion. The splenic iron content decreased significantly in the early stage after reperfusion and then increased time-dependently with increasing reperfusion time, and the hepatic iron content showed a decrease in the early stage after reperfusion. The early decrease of the splenic iron content and hepatic iron content might indicate their contribution to the increase in serum iron in renal IRI. In addition, the duodenal iron content showed time-dependently decreased since 12 h after reperfusion in the IRI groups compared to the control group. Along with the spleen, the duodenum might contribute to the decrease in serum iron in the later stage after reperfusion. The changes in iron metabolism indexes observed in our study demonstrate an iron metabolism disorder in renal IRI, and hepcidin might be involved in maintaining iron homeostasis in renal IRI. These findings might suggest a self-protection mechanism regulating iron homeostasis in IRI and provide a new perspective on iron metabolism in attenuating renal IRI.

Lower Superoxide Dismutase 2 (SOD2) Protein Content in Mononuclear Cells Is Associated with Better Survival in Patients with Hemodialysis Therapy

Mitochondrial superoxide dismutase 2 (SOD2) converts superoxide anions to hydrogen peroxide and oxygen. Human data on SOD2 protein content in chronic kidney disease (CKD) are sparse and mortality data are lacking. We investigated SOD2 protein content in monocytes from patients with hemodialysis therapy (n = 81), CKD stage 1-5 (n = 120), and healthy controls (n = 13) using in-cell Western assays. SOD2 protein decreased from CKD stage 1 until stage 4 whereas it increased again in stage 5 with and without hemodialysis. SOD2 gene expression, analyzed by quantitative real-time PCR, was not significantly different between the groups. Elevating cellular superoxide production reduced SOD2 protein content. This effect was abolished by the superoxide dismutase mimetic Tempol. Using gelelectrophoresis and Western blot we did not detect nitrotyrosine modifications of SOD2 in CKD. Finally, in patients with CKD stage 5 with hemodialysis therapy higher than median SOD2 protein content was associated with higher all-cause mortality. In conclusion, SOD2 protein content declined in CKD until stage 4 while SOD2 gene expression did not. Increased cellular superoxide anion production might affect SOD2 protein content. In advanced CKD (stage 5) SOD2 protein content increased again, but higher than median SOD2 protein content in these patients did not confer a survival benefit.

Iron Therapy Challenges for the Treatment of Nondialysis CKD Patients

The clinical consequences of untreated, severe anemia in patients with nondialysis CKD can be significant, but disparities exist in the anemia treatment guidelines and position papers issued from working groups and associations across the world. These differ in hemoglobin target and iron levels and their emphasis on various iron markers and other clinical outcomes. Not surprisingly, disparities are observed in anemia treatment strategies among patients with nondialysis CKD across different areas of the world. Over the past decade, the prescription and dosage of both iron therapies and erythropoiesis-stimulating agents have shifted, with notable regional differences observed. Moreover, there is ongoing debate regarding oral versus intravenous administration of iron. Compared with oral iron therapy, which often leads to gastrointestinal adverse events, low patient adherence, and low efficacy, intravenous iron administration has been associated with potential serious adverse events, such as anaphylaxis. New iron-based compounds and drugs currently under development are reviewed to describe their potential benefits in the treatment of anemia in patients with CKD. New oral compounds, including iron-based phosphate binders, heme iron polypeptide, and liposomal iron, show different rates of absorption with possibly different efficacy and improved tolerability. These new potential therapies offer health care providers additional anemia treatment options for their patients with CKD; however, the management of anemia in the CKD population continues to present challenges that require prospective studies to identify the optimal iron therapy for patients.

The progress of inflammation and oxidative stress in patients with chronic kidney disease

BACKGROUND

The variations and their correlation of inflammation and oxidative stress in chronic kidney disease (CKD) have not been thoroughly understood.

MATERIALS AND METHODS

Biomarkers of inflammation and oxidative stress were measured in a cohort of 176 patients with CKD ranging from stage 1 to 5 and 67 healthy controls. Correlation analysis in levels between inflammation and oxidative stress was also performed with estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease (MDRD) formula. Concentrations of serum creatinine (Scr), hs-CRP (hypersensitive C reactive protein) and MDA (malondialdehyde) of these participants were measured again after 12 month follow-up.

RESULTS

In the present study, with the development of CKD, serum levels of hs-CRP, interleukin-6 (IL-6) and MDA were significantly increased, and the serum levels of SOD (superoxide dismutase) and GSH-PX (glutathione peroxidase) were significantly decreased in these participants. eGFR was inversely associated with MDA and positively with SOD and GSH-PX when adjusting for age and hypertension therapy. IL-6 and hs-CRP were positively correlated with MDA, and negatively associated with SOD and GSH-PX. Notably, after 12-month follow-up, the increase in Scr was positively associated with the increase in hs-CRP (p < 0.01) and MDA (p < 0.05), respectively.

CONCLUSIONS

Inflammation and oxidative stress interacted with each other and played pivotal roles in the development of CKD. Variation in eGFR was parallel with the changes of oxidative stress and inflammation when CKD developing.

The relationship between deiodinase activity and inflammatory responses under the stimulation of uremic toxins

Background

It is unclear to what extent uremic toxins participate in inflammatory responses and the activities of deiodinases, as well as the effects of deiodinases on inflammatory cytokines.

Materials and methods

Hepatocellular carcinoma cell lines (HepG2) were transfected with small interfering ribonucleic acid (siRNA) specific for deiodinase type 1 (DIO1) and cultured with or without uremic toxins. The mRNA expression of DIO1, interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α was detected by quantitative real-time PCR. The presence of selenoprotein M (SelM) and DIO1 was assessed by western blotting. Sonicate deiodinase activities in HepG2 cells were measured by a dithiothreitol-stimulated assay. The NF-κB, AP-1 and CREB-1 inflammatory signal pathways were confirmed by EMSA.

Results

After culturing for 24 h, the mRNA expression of DIO1 was significantly decreased by the specific siRNA (reduced by 76%, P = 0.0002). Uremic toxins significantly increased the mRNA expression (P < 0.01) of IL-1β, IL-6 and TNF-α and inhibited DIO1 mRNA expression (P < 0.01) compared with controls. Suppression of DIO1 by siRNA significantly decreased the mRNA expression of IL-1β and IL-6 (P < 0.05) but not TNF-α (P = 0.093). Uremic toxins and specific siRNA synchronously reduced the protein expression of SelM and DIO1.

Conclusions

Uremic toxins activate the expression of inflammatory cytokines. The major findings of this study indicate that the uremic toxins, more than inflammatory cytokines, play direct inhibitory roles in DIO1 enzyme activity, which then provides a negative feedback to the growing accumulation of inflammatory cytokines.

Curcumin induces Nrf2 nuclear translocation and prevents glomerular hypertension, hyperfiltration, oxidant stress, and the decrease in antioxidant enzymes in 5/6 nephrectomized rats

Renal injury resulting from renal ablation induced by 5/6 nephrectomy (5/6NX) is associated with oxidant stress, glomerular hypertension, hyperfiltration, and impaired Nrf2-Keap1 pathway. The purpose of this work was to know if the bifunctional antioxidant curcumin may induce nuclear translocation of Nrf2 and prevents 5/6NX-induced oxidant stress, renal injury, decrease in antioxidant enzymes, and glomerular hypertension and hyperfiltration. Four groups of rats were studied: (1) control, (2) 5/6NX, (3) 5/6NX +CUR, and (4) CUR (n = 8–10). Curcumin was given by gavage to NX5/6 +CUR and CUR groups (60 mg/kg/day) starting seven days before surgery. Rats were studied 30 days after NX5/6 or sham surgery. Curcumin attenuated 5/6NX-induced proteinuria, systemic and glomerular hypertension, hyperfiltration, glomerular sclerosis, interstitial fibrosis, interstitial inflammation, and increase in plasma creatinine and blood urea nitrogen. This protective effect was associated with enhanced nuclear translocation of Nrf2 and with prevention of 5/6NX-induced oxidant stress and decrease in the activity of antioxidant enzymes. It is concluded that the protective effect of curcumin against 5/6NX-induced glomerular and systemic hypertension, hyperfiltration, renal dysfunction, and renal injury was associated with the nuclear translocation of Nrf2 and the prevention of both oxidant stress and the decrease of antioxidant enzymes.

Correlation between Ischaemia-Modified Albumin and Intermediate-Density Lipoprotein in Haemodialysis Patients with End-Stage Renal Disease

This study investigated the association between ischaemia-modified albumin (IMA), a biomarker of cardiac ischaemia, and increases in the levels of intermediate-density lipoprotein (IDL), an atherogenic particle that can cause oxidative stress, in haemodialysis patients with end-stage renal disease (ESRD). Fasting levels of serum IMA and lipids/lipoproteins were analysed in 15 patients and 15 healthy control subjects. There was a close positive correlation between IMA and IDL levels in ESRD patients but no significant correlation between IMA and lipids/lipoproteins in control subjects. This suggests a possible link between the characteristic dyslipo-proteinaemia found in ESRD and levels of IMA and, if confirmed in studies with larger sample sizes, may lead to further studies on the potential of the relationship between IMA and IDL as a biomarker in haemodialysis patients with ESRD.

Sleep pattern in an experimental model of chronic kidney disease

The prevalence of sleep disorders is significantly elevated in chronic kidney disease (CKD) patients. Numerous factors likely contribute to the high prevalence of sleep problems in uremic patients. The objective of this study was to evaluate the long-term sleep pattern changes in uremic rats during disease progression. Sleep recordings of the rats were monitored during light and dark periods that lasted 12 h each. These recordings were performed on days 7, 30, 60, and 90 after CKD induction. Cardiovascular, hormonal, and biochemical changes were evaluated at these same time points in control and uremic rats. CKD progression was reflected by the presence of hypertension and progressive increases in urea, creatinine, and cholesterol levels. We also observed hormonal fluctuations of corticosterone and ACTH, which indicated a potential alteration in the hypothalamic-pituitary-adrenal axis in diseased rats. In addition, rats with CKD demonstrated fragmented sleep with a greater number of arousals and decreased sleep efficiency in the light period during disease progression. In the dark period, there was an initial increase in sleep efficiency in CKD rats, but after 90 days of CKD, these animals slept less compared with the control group. Collectively, these metabolic and cardiovascular changes were associated with the persistent alterations in sleep architecture observed in CKD rats.

Anemia and anemia correction: surrogate markers or causes of morbidity in chronic kidney disease?

Observational studies have shown a strong positive correlation between the severity of anemia and the risk of poor outcomes in patients with chronic kidney disease (CKD). This observation was initially taken to imply that adverse outcomes in CKD are caused by anemia. However, the assumption of causality ignores the possibility that anemia and adverse outcomes might be unrelated and that both are caused by underlying inflammation, oxidative stress and comorbid conditions. Randomized clinical trials of anemia correction have revealed an increased risk of adverse cardiovascular outcomes in patients assigned to normal, rather than subnormal, hemoglobin targets. As a result, correction of anemia is now considered potentially hazardous in patients with CKD. Notably, individuals who did not reach the target hemoglobin level in the clinical trials, despite receiving high doses of erythropoietin and iron, experienced a disproportionately large share of the adverse outcomes. These observations point to overdose of erythropoietin and iron, rather than anemia correction per se, as the likely culprit. This Review explores the reasons for the apparent contradiction between the findings of observational studies and randomized clinical trials of anemia treatment in CKD. I have focused on data from basic and translational studies, which are often overlooked in the design and interpretation of clinical studies and in the formulation of clinical guidelines.

Indoxyl sulfate reduces superoxide scavenging activity in the kidneys of normal and uremic rats

BACKGROUND/AIM

Indoxyl sulfate (IS) is a uremic toxin that accelerates the progression of chronic renal failure (CRF). This study aimed at determining whether IS impairs antioxidative systems (redox status) in the kidney.

METHODS

IS was orally administered to normal and subtotally nephrectomized (three fourths and five sixths) rats (CRF rats) for 2 weeks. By use of in vivo and ex vivo electron spin resonance spectroscopy, the kidney redox status was evaluated using carbamoyl-PROXYL as a radical spin probe in living rats, and the kidney superoxide scavenging activity was measured. Immunohistochemistry of superoxide dismutase (SOD) in the kidney was performed.

RESULTS

Administration of IS increased serum and kidney levels of IS and serum creatinine and decreased creatinine clearance. CRF rats showed reduced spin reduction rate, prolonged half-life of the spin probe, and reduced superoxide scavenging activity and SOD-positive areas in the kidney as compared with normal rats. Administration of IS further reduced radical spin reduction rate, prolonged half-life of the spin probe, and reduced superoxide scavenging activity and SOD-positive areas in the kidneys.

CONCLUSIONS

Administration of IS reduced superoxide scavenging activity in the kidneys of normal and CRF rats. Thus, the nephrotoxicity of IS may be induced by impairing the antioxidative systems in the kidney.

Acute injury with intravenous iron and concerns regarding long-term safety

Intravenous iron is widely used to maintain adequate iron stores and prevent iron deficiency anemia in patients with chronic kidney disease, yet concerns remain about its long-term safety with respect to oxidative stress, kidney injury, and accelerated atherosclerosis, which are the subjects of this review. Three parenteral iron formulations are available for use in the United States: Iron dextran, iron gluconate, and iron sucrose. Iron dextran, especially the high molecular form, has been linked with anaphylactoid and anaphylactic reactions, and its use has been declining. A portion of intravenous iron preparations is redox-active, labile iron available for direct donation to transferrin. In vitro tests show that commonly available intravenous iron formulations have differing capacities to saturate transferrin directly: Iron gluconate > iron sucrose > iron dextran. Intravenous iron treatment produces oxidative stress, as demonstrated by increases in plasma levels of lipid peroxidation products (malondialdehyde), at a point that is much earlier than the time to peak concentration of catalytically active iron, suggesting a direct effect of iron sucrose on oxidative stress. Furthermore, iron sucrose infusion produces endothelial dysfunction that seems to peak earlier than the serum level of free iron. Intravenous iron sucrose infusion also has been shown to produce acute renal injury and inflammation as demonstrated by increased urinary albumin, enzyme (N-acetyl-beta-glucosaminidase), and cytokine (chemokine monocyte chemoattractant protein-1) excretions. Although the long-term dangers of intravenous iron are unproved, these data call for examination of effects of intravenous iron on the potential for long-term harm in patients with chronic kidney disease.

Renoprotective and antihypertensive effects of S-allylcysteine in 5/6 nephrectomized rats

Progressive renal damage and hypertension are associated with oxidative and nitrosative stress. On the other hand, S-allylcysteine (SAC), the most abundant organosulfur compound in aged garlic extract (AG), has antioxidant properties. The effects of SAC and AG on blood pressure, renal damage, and oxidative and nitrosative stress were studied in five-sixths nephrectomized rats treated with SAC (200 mg/kg ip) and AG (1.2 ml/kg ip) every other day for 30 days. Proteinuria and serum creatinine and blood urea nitrogen concentrations were measured on days 0, 5, 10, 15, and 30, and systolic blood pressure was recorded on days 0, 15, and 30. The degree of glomerulosclerosis and tubulointerstitial damage, the immunostaining for inducible nitric oxide synthase, 3-nitrotyrosine, poly(ADP-ribose), and the subunits of NADPH oxidase p22phox and gp91phox, and the activity of SOD were determined on day 30. SAC and AG reduced hypertension, renal damage, and the abundance of inducible nitric oxide synthase, 3-nitrotyrosine, poly(ADP-ribose), p22phox, and gp91phox and increased SOD activity. Our data suggest that the antihypertensive and renoprotective effects of SAC and AG are associated with their antioxidant properties and that they may be used to ameliorate hypertension and delay the progression of renal damage.

HFE gene mutations and oxidative stress influence serum ferritin, associated with vascular damage, in hemodialysis patients

BACKGROUND/AIMS

Hyperferritinemia has been associated with cardiovascular mortality in hemodialysis patients. The aim of this study was to evaluate whether serum ferritin was affected by iron and oxidative status and by genetic factors (HFE mutations and the Ala9Val MnSOD polymorphism), and to assess the association between ferritin and cardiovascular damage evaluated by ecocolor-Doppler.

METHODS

63 hemodialysis patients were tested for HFE and MnSOD genotype by restriction analysis and oxidative status; vascular damage was assessed by measuring intima-media thickness, and by detecting plaques at carotid and femoral arteries.

RESULTS

Ferritin was correlated with transferrin saturation (p = 0.003), decreased iron-specific serum antioxidant activity (p = 0.01), age (p = 0.03), and C282Y and H63D HFE mutations (p = 0.05), but not with the MnSOD polymorphism. Ferritin was associated with advanced vascular damage, as evaluated by the presence of plaques, both at carotid (p = 0.03) and femoral arteries (p = 0.001), the other risk factors being age and low albumin. Low iron-specific antioxidant activity was associated with carotid plaques (p = 0.03).

CONCLUSION

In hemodialysis patients, hyperferritinemia reflects a relative increase in iron availability and a decrease in iron-specific antioxidant activity, is favored by HFE mutations, and represents a risk factor for advanced cardiovascular damage.

Spontaneous leukocyte activation and oxygen-free radical generation in end-stage renal disease

Oxidative stress and inflammation are common features and major mediators of atherosclerosis in end-stage renal disease (ESRD). Available evidence for oxidative stress in ESRD is indirect and based on accumulation of byproducts of interactions of reactive oxygen species (ROS) with various molecules. Inflammation is a major cause of oxidative stress. To explore the direct link between oxidative stress and inflammation in ESRD, we studied leukocyte integrin expression and ROS production in 18 ESRD patients and 18 controls. ESRD patients showed elevated plasma malondialdehyde (MDA) and increased superoxide and hydrogen peroxide (H(2)O(2)) production by granulocytes and monocytes before dialysis. Hemodialysis resulted in a further rise in plasma MDA and H(2)O(2) production by granulocytes and monocytes. Surface expression of Mac-1 (CD11b and CD18) on granulocytes and monocytes was significantly increased (denoting cell activation) in ESRD patients. Granularity of granulocytes was significantly reduced before dialysis and declined further after dialysis. The magnitude of ROS production by granulocytes and monocytes was directly related with CD11b expression as well as plasma ferritin and parathyroid hormone levels and was inversely related to protein catabolic rate. Thus, this study provides direct evidence of spontaneous leukocyte activation and increased ROS generation (hence the link between oxidative stress and inflammation) in ESRD patients.

Subtypes and One-Year Survival of First-Ever Stroke in Chinese Patients: The Nanjing Stroke Registry

BACKGROUND

Morbidity and mortality of stroke have been investigated extensively in Western populations, while data concerning case fatality and cause of death after stroke are very limited in mainland China. This study aimed to analyze the 1-year survival and predictors of case fatality in Chinese patients with first-ever stroke.

METHODS

Subjects are patients registered in the Nanjing Stroke Registry Program. Information concerning cardiovascular risk factors and stroke characteristics were collected, and patients were followed after registration. Ischemic strokes were classified according to TOAST criteria as large-artery atherosclerosis (LAA), cardiac embolism stroke (CES), small-vessel stroke (SVS), or other determined and undetermined causes (UND). One-year case fatality was analyzed by the Kaplan-Meier method, and predictors of case fatality were evaluated by the Cox proportional hazards model.

RESULTS

A total of 752 patients with first-ever stroke were included, of which 142 (18.9%) were identified as intracerebral hemorrhage (ICH), 120 (16.0%) as LAA, 123 (16.4%) as SVS, 160 (21.3%) as CES and 216 (28.7%) as UND. The overall survival rate was 86.4% at the end of the 1-year follow-up. Patients with SVS have the highest survival rate (92.7%), followed by UND (89.4%), CES (88.1%) and LAA (84.2%). Patients with ICH have the lowest survival rate (76.8%). Survival rates of patients with different subtypes of stroke presented a significant difference (chi2 = 19.3, p < 0.001). For patients deceased during the first year after the index stroke, 33.3% of deaths were caused by the first stroke, 18.6% by recurrent stroke, 16.7% by cardiovascular comorbidities, 14.7% by nonvascular conditions and 16.7% died of undetermined causes. Advanced age, hypertension, hyperlipidemia, diabetes mellitus (DM), atrial fibrillation (AF), history of transient ischemic attack and cigarette smoking were associated with an increased risk of death 1 year after stroke.

CONCLUSIONS

The case fatality rate and predictors for mortality of Chinese patients with first-ever stroke are similar to those reported for other populations. The significant influence of cardiovascular disease on the first-year survival rate emphasizes the importance of acute stroke management and control of hypertension, DM, AF and other predictors for decreasing case fatality and improving prognosis.

Proinflammatory effects of iron sucrose in chronic kidney disease

Inflammation is a central component of progressive chronic kidney disease (CKD). Iron promotes oxidative stress and inflammatory response in animals and promotes progressive CKD. Parenteral iron provokes oxidative stress in patients with CKD; however, its potential to provoke an inflammatory response is unknown. In 20 veterans with CKD, 100 mg iron sucrose was administered intravenously over 5 min and urinary excretion rate and plasma concentration of monocyte chemoattractant protein-1 (MCP-1) were measured at timed intervals over 24 h. Patients were then randomized to placebo or N-acetyl cysteine (NAC) 600 mg b.i.d. and the experiment was repeated at 1 week. Iron sucrose markedly increased plasma concentration and urinary excretion rate of MCP-1 at baseline and at 1 week visits (P < 0.0001 for time effect). Urinary excretion peaked at 30 min and plasma concentration at 15 min. Plasma MCP-1 concentration fell from 164 +/- 17.7 to 135 +/- 17.7 pg/ml with NAC, whereas it remained unchanged from 133 +/- 12.5 to 132 +/- 17.7 pg/ml with placebo (P=0.001 for visit x antioxidant drug interaction). There was a reduction in MCP-1 urinary excretion rate from visit 1 to 2. At the baseline visit, the urinary excretion rate averaged 305 +/- 66 pg/min and at the second visit 245 +/- 67 pg/min (mean difference 60 +/- 28 pg/min, P = 0.030). There was no improvement in urinary MCP-1 excretion with NAC. In conclusion, iron sucrose causes rapid and transient generation and/or release of MCP-1 plasma concentration and increases urinary excretion rate, and systemic MCP-1 level but the urinary excretion rate is not abrogated with the antioxidant NAC. These results may have implications for the progression of CKD with parenteral iron.

Role of free radicals in aseptic loosening of hip arthroplasty

Fibrous pseudocapsule around hip implants is an invariable finding at revision operations and is believed to release inflammatory mediators that stimulate bone resorption. Reactive oxygen species have been proposed to be causative factors in various disorders with tissue fibrosis. We were interested in investigating whether aseptic loosening is connected with high oxidative stress, and in showing the underlying mechanism of periprosthetic fibrosis and its role in loosening. Levels of oxidative stress markers reduced (GSH) and oxidized (GSSG) gluthatione and malondialdehyde (MDA) were assayed in 28 loose hips and in 12 stable hips revised for high rate of wear and osteolysis. Collagen in the periprosthetic tissues was measured as hydroxyproline content. Osteolysis and polyethylene wear were graded. Increased oxidative stress measured by low GSH/GSSG ratio as well as by increased MDA level was established in patients compared to controls. Oxidative stress markers intercorrelated significantly. MDA and both GSH and GSSG levels correlated significantly with hydroxyproline level. Levels of GSSG and MDA were higher in hips with greater polyethylene wear. The results suggest that high oxidative stress may play a role in formation of a fibrous membrane observed at revision of loose hips. The fibrous pseudocapsule is probably related to high intraarticular pressure and expansion of the effective joint space. This study may elicit some aspects of the pathogenesis of aseptic hip loosening and aid in future investigations aiming at prevention of this complication.

Therapy Insight: congestive heart failure, chronic kidney disease and anemia, the cardio–renal–anemia syndrome

Congestive heart failure (CHF) and chronic kidney disease (CKD) often progress to end stage even with optimum medical therapy. One factor that is common to both conditions is anemia, which is present in about a third of CHF patients. CHF can cause or worsen both anemia and CKD, and CKD can cause or worsen both anemia and CHF. Thus, a vicious circle exists between these three conditions, with each causing or worsening the other. We have called this condition the cardio-renal-anemia syndrome. Anemia in CHF is associated with increased mortality and hospitalization, reduced cardiac function and evidence of more severe CHF and CKD than in nonanemic patients. Intervention studies in anemic CHF patients have shown that optimum medical treatment of CHF and the correction of the associated anemia with subcutaneous erythropoietin and oral iron or intravenous iron sucrose can improve cardiac function, patients' functional status, renal function and quality of life, and reduce the frequency of hospitalization and the dose of diuretics required.