Mechanisms of anemia in CKD

Association of Increased Serum Leptin with Ameliorated Anemia and Malnutrition in Stage 5 Chronic Kidney Disease Patients after Parathyroidectomy

Leptin is an adipokine that regulates various metabolism, but its association with secondary hyperparathyroidism (SHPT), a clinical manifestation of chronic kidney disease-mineral and bone disorder (CKD-MBD), remains obscure. Parathyroidectomy (PTX) is recommended for severe SHPT patients. Here, the associations between circulating leptin and clinical characteristics in CKD patients were investigated. Effects of PTX on leptin production were analyzed in vivo and in vitro. Controls and CKD patients had approximate serum leptin levels in that a larger proportion of CKD patients with body mass index (BMI) <23 kg/m². Serum leptin was related to anemia, albumin, and bone metabolism disorders in CKD patients. Lower intact parathyroid hormone (PTH) was related with higher leptin in PTX patients group. Severe SHPT inhibited uremia-enhanced leptin production in 3T3-L1 adipocytes, which was attenuated after PTX. High levels of PTH were found to reduce Akt phosphorylation and leptin production in vitro but high levels of calcium and phosphorus were not. Successful PTX was found to improve anemia and malnutrition in severe SHPT patients, and this was correlated with increased circulating leptin levels via up-regulated Akt signaling in adipocytes. These findings indicated the therapeutic potential of leptin and related target pathway for improving survival and quality of life in CKD.

[Blood count results from hypertensive patients seen in laboratory of CHU-HJRB Antananarivo in 2013]

INTRODUCTION

The blood count is a routine laboratory test prescribed to patients suffering from high blood pressure. This study aims to describe the results of blood count from hypertensive patients and to identify conditions associated.

METHODS

This retrospective and descriptive study concerns the period from the 1st of December 2012 to 31 th of December 2013 in the laboratory of University Hospital Center CHU-HJRB of Antananarivo. All records of results from hypertensive patients who requested blood count have been exploited.

RESULTS

Among 151 hypertensive patients, 91 (60.3%) had pathological blood counts. Of these, 64 (70.4%) showed one type of abnormality and 27 (29.6%) had multiple abnormalities. The anaemia (33.91%), the leukocytosis (33.04%), the polycythemia (10.43%) and the leukopenia (9.57%) are the most frequent. Among the multiple abnormalities, anaemia associated with leukocytosis is the most observed (29.6%). The microcytosis anaemia (41%) and the neutrophil polymorphonuclear leukocytosis are the most dominant (47.4%). Patients in nephrology (90%) and in endocrinology (81.3%) are the most concerned (p = 0,008). Hypertensive under 20 years old (100%) and women (61.5%) are the most affected (p > 0, 05). The seizures (100%), the edema of the lower limbs (100%) and diabetes (70%) are the signs and pathology most encountered.

CONCLUSION

The blood count should be prescribed for all hypertensive patients to identify the affections that will be treated simultaneously with the high blood pressure. Thus, hypertensive patients will have a good follow-up and their life expectancy will be improved.

A look at risk factors of proteinuria in subjects without impaired renal filtration function in a general population in Owerri, Nigeria

Introduction

Proteinuria is a common marker of kidney damage. This study aimed at determining predictors of proteinuria in subjects without impaired renal filtration function in Owerri, Nigeria.

Methods

This was a cross-sectional study involving 136 subjects, consecutively drawn from Federal Medical Centre (FMC), Owerri, Nigeria. Relevant investigations were performed, including 24-hour urine protein (24HUP). Correlation and multivariate linear regression analysis were used to determine the association and strength of variables to predict proteinuria. Proteinuria was defined as 24HUP ≥0.300g and impaired renal filtration function as creatinine clearance (ClCr) <90mls/min. P<0.05 was taken as statistically significant.

Results

Mean age of subjects was 38.58 ±11.79 years. Female/male ratio was 3:1. High 24-hour urine volume (24HUV) (p<0.001), high spot urine protein/creatinine ratio (SUPCR) (p<0.001), high 24-hour urine protein/creatinine ratio (24HUPCR) (p<0.001), high 24-hour urine protein/osmolality ratio (24HUPOR) (p<0.001), low 24-hour urine creatinine/osmolality ratio (24HUCOR) (p<0.001), and low spot urine protein/osmolality ratio (SUPOR) (p<0.001), predicted proteinuria in this study.

Conclusion

The risk factors of proteinuria in subjects without impaired renal filtration function in Owerri, Nigeria, included 24HUV, SUPCR, 24HUPCR, 24HUPOR, 24HUCOR and SUPOR. Further research should explore the relationship between urine creatinine and urine osmolality, and how this relationship may affect progression of kidney damage, with or without impaired renal filtration function.

Association of Serum Erythropoietin With Cardiovascular Events, Kidney Function Decline, and Mortality: The Health Aging and Body Composition Study

BACKGROUND

Studies suggest that in patients with heart failure (HF), high serum erythropoietin is associated with risk of recurrent HF and mortality. Trials of erythropoietin-stimulating agents in persons with kidney disease have also suggested an increased incidence of adverse clinical events. No large studies of which we are aware have evaluated the association of endogenous erythropoietin levels with clinical outcomes in the community-living older adults.

METHODS AND RESULTS

Erythropoietin concentration was measured in 2488 participants aged 70-79 years in the Health, Aging and Body Composition Study. Associations of erythropoietin with incident HF, coronary heart disease, stroke, mortality, and ≥ 30% decline in estimated glomerular filtration rate were examined using Cox proportional hazards and logistic regression over 10.7 years of follow-up. Mean (SD) age was 75 (3) years and median (quartile 1, quartile 3) erythropoietin was 12.3 (9.0, 17.2) mIU/mL. There were 503 incident HF events, and each doubling of serum erythropoietin was associated with a 25% increased risk of incident HF 1.25 (95% confidence interval 1.13, 1.48) after adjusting for demographics, prevalent cardiovascular disease, cardiovascular disease risk factors, kidney function, and serum hemoglobin. There was no interaction of serum erythropoietin with chronic kidney disease or anemia (P > 0.50). There were 330 incident coronary heart disease events, 161 strokes, 1112 deaths, and 698 outcomes of ≥ 30% decline in estimated glomerular filtration rate. Serum erythropoietin was not significantly associated with these outcomes.

CONCLUSIONS

Higher levels of endogenous erythropoietin are associated with incident HF in older adults. Studies need to elucidate the mechanisms through which endogenous erythropoietin levels associate with specific outcomes.

High Ferritin Level and Malnutrition Predict High Risk of Infection-Related Hospitalization in Incident Dialysis Patients: A Japanese Prospective Cohort Study

AIMS

The aim of the study was to clarify the relationship between serum ferritin and infectious risks.

METHODS

We evaluated all hospital admissions due to infections, clinical biomarkers and nutrition status in 129 incident Japanese dialysis patients during a median follow-up of 38 months.

RESULTS

Kaplan-Meier analysis revealed that the period without infections requiring hospitalization was significantly shorter in ferritin > median (82.0 ng/ml) group than in the ferritin < median group (log-rank test 4.44, p = 0.035). High ferritin was associated with significantly increased relative risk of hospitalization for infection (Cox hazard model 1.52, 95% CI 1.06-2.17). The number of hospitalization days was gradually longer in patients with high ferritin levels and malnutrition.

CONCLUSION

Although serum ferritin levels were low, and doses of iron administered to dialysis patients in Japan are generally lower than in Western countries, an elevated ferritin level was associated with increased risk of infection, particularly in patients with poor nutritional status.

Four-Week Studies of Oral Hypoxia-Inducible Factor-Prolyl Hydroxylase Inhibitor GSK1278863 for Treatment of Anemia

Hypoxia-inducible factor prolyl hydroxylase inhibitors stabilize levels of hypoxia-inducible factor that upregulate transcription of multiple genes associated with the response to hypoxia, including production of erythropoietin. We conducted two phase 2a studies to explore the relationship between the dose of the hypoxia-inducible factor-prolyl hydroxylase inhibitor GSK1278863 and hemoglobin response in patients with anemia of CKD (baseline hemoglobin 8.5-11.0 g/dl) not undergoing dialysis and not receiving recombinant human erythropoietin (nondialysis study) and in patients with anemia of CKD (baseline hemoglobin 9.5-12.0 g/dl) on hemodialysis and being treated with stable doses of recombinant human erythropoietin (hemodialysis study). Participants were randomized 1:1:1:1 to a once-daily oral dose of GSK1278863 (0.5 mg, 2 mg, or 5 mg) or control (placebo for the nondialysis study; continuing on recombinant human erythropoietin for the hemodialysis study) for 4 weeks, with a 2-week follow-up. In the nondialysis study, GSK1278863 produced dose-dependent effects on hemoglobin, with the highest dose resulting in a mean increase of 1 g/dl at week 4. In the hemodialysis study, treatment with GSK1278863 in the 5-mg arm maintained mean hemoglobin concentrations after the switch from recombinant human erythropoietin, whereas mean hemoglobin decreased in the lower-dose arms. In both studies, the effects on hemoglobin occurred with elevations in endogenous erythropoietin within the range usually observed in the respective populations and markedly lower than those in the recombinant human erythropoietin control arm in the hemodialysis study, and without clinically significant elevations in plasma vascular endothelial growth factor concentrations. GSK1278863 was generally safe and well tolerated at the doses and duration studied. GSK1278863 may prove an effective alternative for managing anemia of CKD.

Red blood cell abnormalities and the pathogenesis of anemia in end-stage renal disease

Anemia is the most common hematologic complication in end-stage renal disease (ESRD). It is ascribed to decreased erythropoietin production, shortened red blood cell (RBC) lifespan, and inflammation. Uremic toxins severely affect RBC lifespan; however, the implicated molecular pathways are poorly understood. Moreover, current management of anemia in ESRD is controversial due to the "anemia paradox" phenomenon, which underlines the need for a more individualized approach to therapy. RBCs imprint the adverse effects of uremic, inflammatory, and oxidative stresses in a context of structural and functional deterioration that is associated with RBC removal signaling and morbidity risk. RBCs circulate in hostile plasma by raising elegant homeostatic defenses. Variability in primary defect, co-morbidity, and therapeutic approaches add complexity to the pathophysiological background of the anemic ESRD patient. Several blood components have been suggested as biomarkers of anemia-related morbidity and mortality risk in ESRD. However, a holistic view of blood cell and plasma modifications through integrated omics approaches and high-throughput studies might assist the development of new diagnostic tests and therapies that will target the underlying pathophysiologic processes of ESRD anemia.

Management of anemia in patients with diabetic kidney disease: A consensus statement

This consensus statement focuses on the window of opportunity, which exists while treating patients with diabetic kidney disease and anemia.

Predictor of cardiovascular risks in end stage renal failure patients on maintenance dialysis

Objective:

Cardiovascular disease (CVD) is the main cause of morbidity and premature mortality in end stage renal failure patients (ESRD) receiving dialysis. The aim of our study was to evaluate the impact of various risk factors in this group of high CVD risk patients in local population.

Methods:

We carried out a cross-sectional retrospective study in a single hospital. A total of 136 ESRF patients, consisted of 43 haemodialysis (HD) and 93 continuous ambulatory peritoneal dialysis (CAPD) patients, were recruited and followed up for 36 months duration. Midweek clinical and laboratory data were collected. The occurrence of existing and new CVD events was recorded.

Results:

Multiple Logistic Regression showed pre-existing cardiovascular event (odds ratio, 4.124; 95% confidence interval [CI], 0.990 to 17.187), elevated total cholesterol level (odds ratio, 0.550; 95% CI, 0.315 to 0.963), elevated serum phosphate level (odds ratio, 5.862; 95% CI, 1.041 to 33.024) and elevated random blood glucose level (odds ratio, 1.193; 95% CI, 1.012 to 1.406) were significantly associated with occurrence of CVD events.

Conclusions:

History of cardiovascular event before the initiation of dialysis, elevated level of serum phosphate and random blood glucose levels are the risk factors of CVD whereas paradoxically a high total cholesterol level has CVD protective effect towards the ESRF patients.

Increased Synthesis of Liver Erythropoietin with CKD

Anemia of CKD seems to be related to impaired production of renal erythropoietin (Epo). The glycosylation pattern of Epo depends on the synthesizing cell and thus, can indicate its origin. We hypothesized that synthesis of Epo from nonkidney cells increases to compensate for insufficient renal Epo production during CKD. We determined plasma Epo levels and Epo glycosylation patterns in 33 patients with CKD before undergoing dialysis and nine patients with CKD undergoing dialysis. We compared these values with values obtained in healthy volunteers and other controls. Although patients with CKD before undergoing dialysis had median (interquartile range) Epo levels higher than those of healthy controls (13.8 IU/L; interquartile range, 10.0-20.7 IU/L versus 8.4 IU/L; interquartile range, 7.6-9.0 IU/L; P<0.01), these patients were moderately anemic (mean±SD; hemoglobin =118±17 g/L). Detected as the percentage of migrated isoforms (PMI), Epo glycosylation in patients with CKD before undergoing dialysis (PMI=36.1±11.7%) differed from that in healthy controls (PMI=9.2±3.8%; P<0.01) but not from that in umbilical cord plasma (PMI=53.9±10.6%; P>0.05), which contains mainly liver-derived Epo. Furthermore, glycosylation modification correlated with eGFR loss. These results suggest that patients with CKD maintain persistent Epo synthesis despite declining renal function, and this maintenance may result in part from increased liver Epo synthesis.

Inflammation and functional iron deficiency regulate fibroblast growth factor 23 production

Circulating levels of fibroblast growth factor 23 (FGF23) are elevated in patients with chronic kidney disease (CKD), but the mechanisms are poorly understood. Here we tested whether inflammation and iron deficiency regulate FGF23. In wild-type mice, acute inflammation induced by single injections of heat-killed Brucella abortus or interleukin-1β (IL-1β) decreased serum iron within 6 h, and was accompanied by significant increases in osseous Fgf23 mRNA expression and serum levels of C-terminal FGF23, but no changes in intact FGF23. Chronic inflammation induced by repeated bacteria or IL-1β injections decreased serum iron, increased osseous Fgf23 mRNA, and serum C-terminal FGF23, but modestly increased biologically active, intact FGF23 serum levels. Chronic iron deficiency mimicked chronic inflammation. Increased osseous FGF23 cleavage rather than a prolonged half-life of C-terminal FGF23 fragments accounted for the elevated C-terminal FGF23 but near-normal intact FGF23 levels in inflammation. IL-1β injection increased Fgf23 mRNA and C-terminal FGF23 levels similarly in wildtype and Col4a3(ko) mice with CKD but markedly increased intact FGF23 levels only in the CKD mice. Inflammation increased Fgf23 transcription by activating Hif1α signaling. Thus, inflammation and iron deficiency stimulate FGF23 production. Simultaneous upregulation of FGF23 cleavage in osteocytes maintains near-normal levels of biologically active, intact circulating FGF23, whereas downregulated or impaired FGF23 cleavage may contribute to elevated intact serum FGF23 in CKD.

International Comparisons to Assess Effects of Payment and Regulatory Changes in the United States on Anemia Practice in Patients on Hemodialysis: The Dialysis Outcomes and Practice Patterns Study

For years, erythropoiesis-stimulating agent (ESA) use among patients on dialysis was much higher in the United States than in Europe or Japan. Sweeping changes to dialysis reimbursement and regulatory policies for ESA in the United States in 2011 were expected to reduce ESA use and hemoglobin levels. We used the Dialysis Outcomes and Practice Patterns Study (DOPPS) data from 7129 patients in 223 in-center hemodialysis facilities (average per month) to estimate and compare time trends in ESA dose and hemoglobin levels among patients on hemodialysis in the United States, Germany, Italy, Spain, the United Kingdom, and Japan. From 2010 to 2013, substantial declines in ESA use and hemoglobin levels occurred in the United States but not in other DOPPS countries. Between August of 2010 and April of 2013, mean weekly ESA dose in the United States decreased 40.4% for black patients and 38.0% for nonblack patients; mean hemoglobin decreased from 11.5 g/dl in black patients and 11.4 g/dl in nonblack patients to 10.6 g/dl in both groups. In 2010 and 2013, adjusted weekly ESA doses per kilogram were 41% and 11% lower, respectively, in patients in Europe and 60% and 18% lower, respectively, in patients in Japan than in nonblack patients in the United States. Adjusted hemoglobin levels in 2010 and 2013 were 0.07 g/dl lower and 0.56 g/dl higher, respectively, in patients in Europe and 0.93 and 0.01 g/dl lower, respectively, in patients in Japan than in nonblack patients in the United States. In conclusion, ESA dosing reductions in the United States likely reflect efforts in response to changes in reimbursement policy and regulatory guidance.

Laboratory Profiles of Patients on Hemodialysis - A Retrospective One Year Study in a Rural Tertiary Care Hospital

INTRODUCTION

The global prevalence of chronic kidney disease (CKD) is estimated to be 8-16%. Studies have shown that the increased mortality in patients with CKD is due to anemia that leads to cardiovascular disease (CVD), also known as "Cardio renal anemia syndrome". The present study was undertaken to look into the laboratory profiles of end stage renal disease (ESRD) patients.

AIM

To study the laboratory profiles of End stage renal disease (ESRD) patients coming for hemodialysis.

MATERIALS AND METHODS

The study was a retrospective, cross- sectional study done by collecting data from the medical case records of all patients during a period of one year from January 1(st) 2014 to December 31(st) 2014. Records of a total of 140 patients who underwent hemodialysis during this period were taken. The laboratory profiles that was recorded included haemoglobin, serum sodium, potassium, chloride, fasting glucose, calcium and phosphorus.

RESULTS

The mean age of the subjects was 53.5±14.5 yrs. All the patients had moderate anaemia. There was a significant difference in the mean systolic and diastolic blood pressure, serum creatinine and serum urea values between males and females. The mean serum calcium levels were low.

CONCLUSION

The present study is the first such study in this rural area and shows evidence of a relatively young population with ESRD having moderate anaemia and hypertension. There is evidence of hypocalcaemia and serum phosphorus is on the higher end of the normal range. These findings are usually associated with a higher risk of mortality. With the explosion of diabetes and hypertension in India, chronic kidney disease should be diagnosed and managed as early as possible if not prevented.

How the Target Hemoglobin of Renal Anemia Should Be

Renal anemia is caused by the deficiency of endogenous erythropoietin (Epo) due to renal dysfunction. We think that it is possible to slow the progression of chronic kidney disease (CKD) in case we initiate Epo early in pre-dialysis patients, especially in the non-diabetic population. Erythropoiesis stimulating agent (ESA) treatments targeting mild anemia (10-12 g/dl) can decrease the risk of occurrence of cardiovascular disease (CVD) in patients with hypertension, diabetes mellitus and congestive heart failure. As the large randomized controlled trials such as Cardiovascular Risk Reduction by Early Anemia Treatment with Epoetin Beta, Correction of Hemoglobin and Outcomes in Renal Insufficiency and Trial to Reduce Cardiovascular Events with Aranesp Thearpy in the Western countries suggested, we do not recommend high doses of ESA to achieve the target hemoglobin (Hb) level. The target Hb of >13 g/dl might lead to increase in the risk of CVD although maintaining a high Hb of >12 g/dl without ESA is not harmful for CKD patients. It is desirable to determine the target Hb in dialysis patients depending on their ages. Renal anemia should be monitored constantly to start ESA and iron replacement therapy at an appropriate time, while avoiding their excess in order to minimize the occurrence of CVD and other complications. Taken all the international guidelines and our clinical experiences together, we should consider administration of ESA when the Hb level becomes <11 g/dl in pre-dialysis patients and <10 g/dl in dialysis patients.

Effects of carnitine on oxidative stress response to intravenous iron administration to patients with CKD: impact of haptoglobin phenotype

BACKGROUND

Anemia is a common disorder in CKD patients. It is largely attributed to decreased erythropoietin (EPO) production and iron deficiency. Therefore, besides EPO, therapy includes iron replenishment. However, the latter induces oxidative stress. Haptoglobin (Hp) protein is the main line of defense against the oxidative effects of Hemoglobin/Iron. There are 3 genotypes: 1-1, 2-1 and 2-2. Hp 2-2 protein is inferior to Hp 1-1 as antioxidant. So far, there is no evidence whether haptoglobin phenotype affects iron-induced oxidative stress in CKD patients. Therefore, the present study examines the influence of carnitine treatment on the intravenous iron administration (IVIR)-induced oxidative stress in CKD patients, and whether Hp phenotype affects this response.

METHODS

TRIAL REGISTRATION

Current Controlled Trials ISRCTN5700858. This study included 26 anemic (Hb = 10.23 ± 0.28) CKD patients (stages 3-4) that were given a weekly IVIR (Sodium ferric gluconate, [125 mg/100 ml] for 8 weeks, and during weeks 5-8 also received Carnitine (20 mg/kg, IV) prior to IVIR. Weekly blood samples were drawn before and after each IVIR for Hp phenotype, C-reactive protein (CRP), advanced oxidative protein products (AOPP), neutrophil gelatinase-associated lipocalin (NGAL), besides complete blood count and biochemical analyses.

RESULTS

Eight percent of CKD patients were Hp1-1, 19 % Hp2-1, and 73 % Hp2-2. IVIR for 4 weeks did not increase hemoglobin levels, yet worsened the oxidative burden as was evident by elevated plasma levels of AOPP. The highest increase in AOPP was observed in Hp2-2 patients. Simultaneous administration of Carnitine with IVIR abolished the IVIR-induced oxidative stress as evident by preventing the elevations in AOPP and NGAL, preferentially in patients with Hp2-2 phenotype.

CONCLUSIONS

This study demonstrates that Hp2-2 is a significant risk factor for IVIR-induced oxidative stress in CKD patients. Our finding, that co-administration of Carnitine with IVIR preferentially attenuates the adverse consequences of IVIR, suggests a role for Carnitine therapy in these patients.

Pentoxifylline for Anemia in Chronic Kidney Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Pentoxifylline (PTX) is a promising therapeutic approach for reducing inflammation and improving anemia associated to various systemic disorders. However, whether this agent may be helpful for anemia management also in CKD patients is still object of debate.

STUDY DESIGN

Systematic review and meta-analysis.

POPULATION

Adults with CKD (any KDOQI stage, including ESKD patients on regular dialysis) and anemia (Hb<13 g/dL in men or < 12 g/dL in women).

SEARCH STRATEGY AND SOURCES

Cochrane CENTRAL, EMBASE, Ovid-MEDLINE and PubMed were searched for studies providing data on the effects of PTX on anemia parameters in CKD patients without design or follow-up restriction.

INTERVENTION

PTX derivatives at any dose regimen.

OUTCOMES

Hemoglobin, hematocrit, ESAs dosage and resistance (ERI), iron indexes (ferritin, serum iron, TIBC, transferrin and serum hepcidin) and adverse events.

RESULTS

We retrieved 11 studies (377 patients) including seven randomized controlled trials (all comparing PTX to placebo or standard therapy) one retrospective case-control study and three prospective uncontrolled studies. Overall, PTX increased hemoglobin in three uncontrolled studies but such improvement was not confirmed in a meta-analysis of seven studies (299 patients) (MD 0.12 g/dL, 95% CI -0.22 to 0.47). Similarly, there were no conclusive effects of PTX on hematocrit, ESAs dose, ferritin and TSAT in pooled analyses. Data on serum iron, ERI, TIBC and hepcidin were based on single studies. No evidence of increased rate of adverse events was also noticed.

LIMITATIONS

Small sample size and limited number of studies. High heterogeneity among studies with respect to CKD and anemia severity, duration of intervention and responsiveness/current therapy with iron or ESAs.

CONCLUSIONS

There is currently no conclusive evidence supporting the utility of pentoxifylline for improving anemia control in CKD patients. Future trials designed on hard, patient-centered outcomes with larger sample size and longer follow-up are advocated.

Ferric pyrophosphate citrate (Triferic™) administration via the dialysate maintains hemoglobin and iron balance in chronic hemodialysis patients

Background

Administration of ferric pyrophosphate citrate (FPC, Triferic™) via hemodialysate may allow replacement of ongoing uremic and hemodialysis-related iron losses. FPC donates iron directly to transferrin, bypassing the reticuloendothelial system and avoiding iron sequestration.

Methods

Two identical Phase 3, randomized, placebo-controlled trials (CRUISE 1 and 2) were conducted in 599 iron-replete chronic hemodialysis patients. Patients were dialyzed with dialysate containing 2 µM FPC-iron or standard dialysate (placebo) for up to 48 weeks. Oral or intravenous iron supplementation was prohibited, and doses of erythropoiesis-stimulating agents were held constant. The primary efficacy end point was the change in hemoglobin (Hgb) concentration from baseline to end of treatment (EoT). Secondary end points included reticulocyte hemoglobin content (CHr) and serum ferritin.

Results

In both trials, Hgb concentration was maintained from baseline to EoT in the FPC group but decreased by 0.4 g/dL in the placebo group (P < 0.001, combined results; 95% confidence interval [CI] 0.2–0.6). Placebo treatment resulted in significantly larger mean decreases from baseline in CHr (−0.9 pg versus −0.4 pg, P < 0.001) and serum ferritin (−133.1 µg/L versus −69.7 µg/L, P < 0.001) than FPC treatment. The proportions of patients with adverse and serious adverse events were similar in both treatment groups.

Conclusions

FPC delivered via dialysate during hemodialysis replaces iron losses, maintains Hgb concentrations, does not increase iron stores and exhibits a safety profile similar to placebo. FPC administered by hemodialysis via dialysate represents a paradigm shift in delivering maintenance iron therapy to hemodialysis patients.

Ferric pyrophosphate citrate administered via dialysate reduces erythropoiesis-stimulating agent use and maintains hemoglobin in hemodialysis patients

Ferric pyrophosphate citrate (FPC) is a water-soluble iron salt administered via dialysate to supply iron directly to transferrin. The PRIME study tested whether treatment with FPC could reduce prescribed erythropoiesis-stimulating agent (ESA) use and maintain hemoglobin in hemodialysis patients. This 9-month, randomized, placebo-controlled, double-blind, multicenter clinical study included 103 patients undergoing hemodialysis 3-4 times weekly. The FPC group received dialysate containing 2 μmol/l of iron. The placebo group received standard dialysate. A blinded central anemia management group facilitated ESA dose adjustments. Intravenous iron was administered according to the approved indication when ferritin levels fell below 200 μg/l. The primary end point was the percentage change from baseline in prescribed ESA dose at end of treatment. Secondary end points included intravenous iron use and safety. At the end of treatment, there was a significant 35% reduction in prescribed ESA dose in FPC-treated patients compared with placebo. The FPC patients used 51% less intravenous iron than placebo. Adverse and serious adverse events were similar in both groups. Thus, FPC delivered via dialysate significantly reduces the prescribed ESA dose and the amount of intravenous iron needed to maintain hemoglobin in chronic hemodialysis patients.

What is the Role of HbA1c in Diabetic Hemodialysis Patients?

The definition of a good glycemic control in patients with diabetes mellitus on hemodialysis is far from settled. In the general population, hemoglobin A1c is highly correlated with the average glycemia of the last 8-12 weeks. However, in hemodialysis patients, the correlation of hbA1c with glycemia is weaker as it also reflects changes in hemoglobin characteristics and red blood cells half-life. As expected, studies show that the association between HbA1c and outcomes in these patients differ from the general population. Therefore, the value of HbA1c in the treatment of hemodialysis patients has been questioned. Guidelines are generally cautious in their recommendations about possible targets of HbA1c in this population. Indeed, the risk of not treating hyperglycemia should be weighed against the particularly high risk of precipitating hypoglycemia in dialysis patients. In this review, a critical analysis of the current role of HbA1c in the care of hemodialysis patients is presented.

Defining, Treating, and Understanding Chronic Kidney Disease--A Complex Disorder

Chronic kidney disease (CKD) is prevalent in more than 20 million people in the United States. The majority of care provided to patients with this disease comes from primary care physicians, although it is often poorly understood. After an extensive literature review, it is clear that it can be difficult to classify and there are many barriers to care. Risk factors for both incident CKD and disease progression include hypertension, poor glycemic control, sociodemographic factors, acute kidney injury, metabolic acidosis, and possibly hyperuricemia and dietary factors. Treatment of patients with CKD should focus on mitigating risk factors, as well as common comorbidities such as cardiovascular disease, anemia, and bone mineral disease. Novel therapies such as pirfenidone, pentoxifylline, and endothelin-1 antagonists are being investigated with promising results.

Diagnostic utility of immunochemical fecal occult blood tests to detect lower gastrointestinal lesions in patients with chronic kidney disease

PURPOSE

The immunochemical fecal occult blood test (iFOBT) is a useful method to screen for lower gastrointestinal (GI) bleeding-related lesions. However, few studies have investigated the diagnostic utility of iFOBT in chronic kidney disease (CKD).

METHODS

We included 691 patients with nondialysis-dependent CKD stages 2-5 or those receiving dialysis. Bleeding-related lower GI lesions were identified by colonoscopy, and the diagnostic utility of iFOBT was evaluated.

RESULTS

Bleeding-related lower GI lesions were found in 9.2% of 491 patients with CKD stage 2, 17.8% of 107 patients with CKD stage 3/4, and 25.8% of 93 patients with CKD stage 5/dialysis (p < 0.001). Compared with CKD stage 2, CKD stage 5/dialysis was independently associated with a 2.80-fold risk for bleeding-related lesions (p = 0.019). The iFOBT was positive in 92 (13.3%) patients and the area under the receiver operating curve (AUC) for a bleeding-related lesion was 0.64 (p < 0.001). The sensitivity of iFOBT increased as the CKD stage worsened (20.0 vs 52.6 vs 58.3%; p = 0.002). However, the specificity to detect bleeding-related lesions decreased with the severity of CKD stage (94.6 vs. 78.4 vs. 76.8%; p < 0.001). The AUC of iFOBT to detect adenoma or carcinoma was 0.54 (p = 0.046), and a similar pattern of sensitivity and specificity was observed between different CKD stages.

CONCLUSIONS

The prevalence of bleeding-related lower GI lesions and the sensitivity of iFOBT to detect these GI lesions increased in advanced CKD. However, iFOBT should be used cautiously in these patients because its specificity decreased.

Hypoxia Signaling Cascade for Erythropoietin Production in Hepatocytes

Erythropoietin (Epo) is produced in the kidney and liver in a hypoxia-inducible manner via the activation of hypoxia-inducible transcription factors (HIFs) to maintain oxygen homeostasis. Accelerating Epo production in hepatocytes is one plausible therapeutic strategy for treating anemia caused by kidney diseases. To elucidate the regulatory mechanisms of hepatic Epo production, we analyzed mouse lines harboring liver-specific deletions of genes encoding HIF-prolyl-hydroxylase isoforms (PHD1, PHD2, and PHD3) that mediate the inactivation of HIF1α and HIF2α under normal oxygen conditions. The loss of all PHD isoforms results in both polycythemia, which is caused by Epo overproduction, and fatty livers. We found that deleting any combination of two PHD isoforms induces polycythemia without steatosis complications, whereas the deletion of a single isoform induces no apparent phenotype. Polycythemia is prevented by the loss of either HIF2α or the hepatocyte-specific Epo gene enhancer (EpoHE). Chromatin analyses show that the histones around EpoHE dissociate from the nucleosome structure after HIF2α activation. HIF2α also induces the expression of HIF3α, which is involved in the attenuation of Epo production. These results demonstrate that the total amount of PHD activity is more important than the specific function of each isoform for hepatic Epo expression regulated by a PHD-HIF2α-EpoHE cascade in vivo.

Hemoglobin discriminates stages of chronic kidney disease in elderly patients

The prevalence of chronic kidney disease (CKD) increases with age, and anemia is known to affect the outcome of subjects with CKD. However, little is known with regard to the associations between metabolic complications and stages of CKD among elderly patients. Thus, the aim of the present study was to investigate the prevalence of CKD in elderly Chinese patients, as well as the associations between stages of CKD and clinically important complications of anemia. In total, 2,258 individuals with CKD, divided into younger (n=989) and elderly (n=1,269) groups, were enrolled in the study between June 2009 and December 2011. The glomerular filtration rate (GFR) was assessed using a 99mTc-DTPA renal dynamic imaging method (modified Gate's method). The levels of serum creatinine (SCr) and hemoglobin (Hb), and the hematocrit (HCT) were measured simultaneously per manufacturer's instructions. In the elderly group, the levels of SCr and proportional ratios were higher, while the GFR, Hb level, HCT and proportional ratios were lower when compared with the values in the younger group. Statistically significant differences were observed in the Hb concentrations when comparing individuals classified with different stages of CKD in the younger and elderly groups. In the younger group, there was no significant difference in the Hb concentrations between the stage 3a and 3b CKD patients. However, in the elderly group, the Hb concentrations were significantly higher in patients classified with stage 3a CKD when compared with those with stage 3b, whose GFR cutoff point was <60 ml/min/1.73 m². In conclusion, the results indicated that Hb levels may be used to discriminate stages of CKD in elderly patients; thus, Hb may be used as a biomarker to assess the severity of CKD.

Longitudinal changes in hematocrit in hypertensive chronic kidney disease: results from the African-American Study of Kidney Disease and Hypertension (AASK)

BACKGROUND

Anemia is common in chronic kidney disease (CKD) and associated with poor outcomes. In cross-sectional studies, lower estimated glomerular filtration rate (eGFR) has been associated with increased risk for anemia. The aim of this study was to determine how hematocrit changes as eGFR declines and what factors impact this longitudinal association.

METHODS

We followed 1094 African-Americans with hypertensive nephropathy who participated in the African-American Study of Kidney Disease and Hypertension. Mixed effects models were used to determine longitudinal change in hematocrit as a function of eGFR. Interaction terms were used to assess for differential effects of age, gender, baseline eGFR, baseline proteinuria, malnutrition and inflammation on eGFR-associated declines in hematocrit. In sensitivity analyses, models were run using iGFR (by renal clearance of I(125) iothalamate) in place of eGFR.

RESULTS

At baseline, mean hematocrit was 39% and 441 (40%) individuals had anemia. The longitudinal relationship between eGFR and hematocrit differed by baseline eGFR and was steeper when baseline eGFR was <45 mL/min/1.73 m(2). For example, the absolute decline in hematocrit per 10 mL/min/1.73 m(2) decline in longitudinal eGFR was -3.7, -1.3 and -0.5% for baseline eGFR values of 20, 40 and 60 mL/min/1.73 m(2), respectively (P < 0.001 comparing the longitudinal association between baseline eGFR = 40 or 60 versus baseline eGFR = 20 mL/min/1.73 m(2)). Similarly, male sex, younger age (<65 years) and higher baseline proteinuria (protein-to-creatinine ratio >0.22) were associated with greater hematocrit declines per unit decrease in longitudinal eGFR compared with female sex, older age and low baseline proteinuria, respectively (P-interaction <0.05 for each comparison). The longitudinal eGFR-hematocrit association did not differ by body mass index, serum albumin or C-reactive protein.

CONCLUSIONS

Men, younger individuals and those with low baseline eGFR (<45 mL/min/1.73 m(2)) or baseline proteinuria are particularly at risk for eGFR-related declines in hematocrit.

Hepcidin levels in chronic hemodialysis patients: a critical evaluation

Altered systemic iron metabolism is a key element of uremia, and functional iron deficiency mainly related to subclinical inflammation makes it difficult to maintain proper control of anemia in chronic hemodialysis patients (CHD). In the last decade, the hepatic hormone hepcidin has been progressively recognized as the master regulator of circulating iron levels through the modulation of cellular iron fluxes in response to iron stores, as well as to erythroid and inflammatory stimuli. Hepcidin is cleared by the kidney and progression of renal disease has been associated to increased serum hepcidin levels. This, in turn, reduces iron availability for erythropoiesis, suggesting anti-hepcidin strategies for improving anemia control. Moreover, hepcidin has been recently implicated in the pathogenesis of long-term complications of dialysis, like accelerated atherosclerosis. Initial studies almost invariably reported a sustained increase of serum hepcidin in chronic hemodialysis patients. Noteworthy, such studies included relatively few patients and controls that were poorly matched for major determinants of serum hepcidin at population level, i.e., age and gender. More recent data based on accurately matched larger series challenge the view that hepcidin is intrinsically increased in hemodialysis patients, showing a marked inter- and intra-individual variability of hormone levels. Here we take a critical look to the data published so far on hepcidin levels in CHD, analyze the reasons underlying the discrepancies in available studies and the hepcidin variability in CHD, and point out the need for further studies in large series of well-characterized CHD patients and controls.

Anaemia in chronic obstructive pulmonary disease: an insight into its prevalence and pathophysiology

Chronic obstructive pulmonary disease (COPD) is a major health problem, with increasing morbidity and mortality. There is a growing literature regarding the extra-pulmonary manifestations of COPD, which can have a significant impact on symptom burden and disease progression. Anaemia is one of the more recently identified co-morbidities, with a prevalence that varies between 4.9% and 38% depending on patient characteristics and the diagnostic criteria used. Systemic inflammation seems to be an important factor for its establishment and repeated bursts of inflammatory mediators during COPD exacerbations could further inhibit erythropoiesis. However, renal impairment, malnutrition, low testosterone levels, growth hormone level abnormalities, oxygen supplementation, theophylline treatment, inhibition of angiotensin-converting enzyme and aging itself are additional factors that could be associated with the development of anaemia. The present review evaluates the published literature on the prevalence and significance of anaemia in COPD. Moreover, it attempts to elucidate the reasons for the high variability reported and investigates the complex pathophysiology underlying the development of anaemia in these patients.

Biosimilar ESAs: a comparative review

BACKGROUND

The management of anaemia in patients with chronic kidney disease has been transformed by development of erythropoiesis-stimulating agents (ESAs). Following expiry of the patent of the originator epoetin alfa in Europe, a number of biosimilar ESAs have been licensed for use in the nephrology setting. Biosimilars are biological medicines that are approved via stringently defined regulatory pathways on the basis that they have demonstrated comparable safety, efficacy and quality to their reference product.

OBJECTIVES

As nurses have a pivotal role in patient care, not only administering medications but also educating patients about their treatment options, it is important that nurses understand the differences between biosimilar medicines and their reference products and appreciate the stringent regulatory requirements for approval of biosimilars.

METHODS

In this review, we use epoetin zeta as a case study to highlight practical considerations of using biosimilar ESAs in the management of patients with kidney disease.

RESULTS AND CONCLUSION

Biosimilar products, such as epoetin zeta, may offer a range of features to patients, nurses and physicians, such as greater flexibility over dose and route of administration, in addition to greater access to biological medicines through cost savings.

APPLICATION TO PRACTICE

Renal nurses play a significant role in the management of patients with kidney disease and anaemia, not only having an important role in the delivery of medicine but also in the education of patients. This review discusses some of the practical aspects associated with the use of biosimilar medicines to assist nurses in making informed decisions over their use.

Intravenous iron administration is associated with reduced platelet counts in patients with chronic kidney disease

WHAT IS KNOWN AND OBJECTIVE

In the management of anaemia associated with chronic kidney disease (CKD), optimal use of intravenous (i.v.) iron has a central role. It minimizes reliance on erythropoiesis-stimulating agents (ESAs) and may be beneficial in reducing overall cardiovascular risks through its effects on platelet counts (PLT). We have examined the effects of i.v. iron on PLT in patients with CKD.

METHODS

Two hundred and three patients with CKD, referred to a single teaching hospital in UK for i.v. iron therapy, received low molecular-weight iron dextran at a median dose of 1000 milligrams given over a median time of 2 h and 40 min. PLT at baseline were compared with the measurements taken during a 4-month follow-up period post-infusion.

RESULTS

PLT were checked at various points following i.v. iron treatment. Compared with baseline, mean reduction in PLT ranged between 10.1 and 23.6 (×10(9) /L) during consecutive 15-days intervals post-treatment. At the reference point of 90-days post-infusion, the drop in PLT was statistically significant (P < 0.001).

WHAT IS NEW AND CONCLUSION

Low molecular-weight iron dextran in patients with CKD leads to reduction in PLT. This reduction appears soon after treatment and is maximal after 3 months. Prospective data are required to confirm these findings and examine whether this translates to a reduction in thrombotic episodes.

Recent advances in the management of hemodialysis patients: a focus on cardiovascular disease

The number of patients requiring chronic hemodialysis is rapidly growing worldwide. Hemodialysis both greatly reduces quality of life and is associated with extremely high mortality rates. Management of care of patients requiring chronic hemodialysis is complex, and randomized controlled trials aimed at reducing primary outcomes of cardiovascular disease events, mortality, or both in this population have largely been unsuccessful. Topics of major concern in the management of maintenance hemodialysis patients as related to these outcomes include the overall cardiovascular disease burden, blood pressure control, anemia, abnormalities in mineral metabolism, and inflammation. The focus of this review is a discussion of these topics on the basis of current recommendations from major organizations, expert opinion, and the available randomized controlled trials to date. These issues are further complicated by sometimes conflicting observational and randomized controlled trial data. Overall, treatment options for reducing these endpoints in maintenance hemodialysis patients are limited, and future randomized controlled trials are essential to continuing to advance care in this population, with the goal of ultimately improving hard outcomes. Such trials should consider new therapies to better target these factors, additional risk factors that have not been well tested to date, and therapies with new targets, including inflammation.

Anemia in Adenine-Induced Chronic Renal Failure and the Influence of Treatment With Gum Acacia Thereon

Anemia frequently complicates chronic kidney disease (CKD). We investigated here the effect of adenine-induced CKD in rats on erythrocyte count (EC), hematocrit (PCV) and hemoglobin (Hb) concentration, as well as on the activity of L-γ-glutamyl transferase (GGT) and the concentrations of iron (Fe), transferrin (Tf), ferritin (F), total iron binding capacity (TIBC) / unsaturated iron binding capacity (UIBC) and hepcidin (Hp) in serum and erythropoietin (Epo) in renal tissue. Renal damage was assessed histopathologically, and also by measuring the serum concentrations of the uremic toxin indoxyl sulfate (IS), creatinine, and urea, and by creatinine clearance. We also assessed the influence of concomitant treatment with gum acacia (GA) on the above analytes. Adenine feeding induced CKD, accompanied by significant decreases (P<0.05) in EC, PCV, and Hb, and in the serum concentrations of Fe, Tf, TIBC, UIBC and Epo. It also increased Hp and F levels. GA significantly ameliorated these changes in rats with CKD. A general improvement in the renal status of rats with CKD after GA is shown due to its anti-inflammatory and anti-oxidant actions, and reduction of the uremic toxin IS, which is known to suppress Epo production, and this may be a reason for its ameliorative actions on the indices of anemia studied.

Kidney pericytes: roles in regeneration and fibrosis

Renal pericytes have been neglected for many years, but recently they have become an intensively studied cell population in renal biology and pathophysiology. Pericytes are stromal cells that support vasculature, and a subset of pericytes are mesenchymal stem cells. In kidney, pericytes have been reported to play critical roles in angiogenesis, regulation of renal medullary and cortical blood flow, and serve as progenitors of interstitial myofibroblasts in renal fibrogenesis. They interact with endothelial cells through distinct signaling pathways and their activation and detachment from capillaries after acute or chronic kidney injury may be critical for driving chronic kidney disease progression. By contrast, during kidney homeostasis it is likely that pericytes serve as a local stem cell population that replenishes differentiated interstitial and vascular cells lost during aging. This review describes both the regenerative properties of pericytes as well as involvement in pathophysiologic conditions such as fibrogenesis.

Hepcidin as a predictive factor and therapeutic target in erythropoiesis-stimulating agent treatment for anemia of chronic disease in rats

Anemia of chronic disease is a multifactorial disorder, resulting mainly from inflammation-driven reticuloendothelial iron retention, impaired erythropoiesis, and reduced biological activity of erythropoietin. Erythropoiesis-stimulating agents have been used for the treatment of anemia of chronic disease, although with varying response rates and potential adverse effects. Serum concentrations of hepcidin, a key regulator of iron homeostasis, are increased in patients with anemia of chronic disease and linked to the pathogenesis of this disease, because hepcidin blocks cellular iron egress, thus limiting availability of iron for erythropoiesis. We tested whether serum hepcidin levels can predict and affect the therapeutic efficacy of erythropoiesis-stimulating agent treatment using a well-established rat model of anemia of chronic disease. We found that high pre-treatment hepcidin levels correlated with an impaired hematologic response to an erythropoiesis-stimulating agent in rats with anemia of chronic disease. Combined treatment with an erythropoiesis-stimulating agent and an inhibitor of hepcidin expression, LDN-193189, significantly reduced serum hepcidin levels, mobilized iron from tissue stores, increased serum iron levels and improved hemoglobin levels more effectively than did the erythropoiesis-stimulating agent or LDN-193189 monotherapy. In parallel, both the erythropoiesis-stimulating agent and erythropoiesis-stimulating agent/LDN-193189 combined reduced the expression of cytokines known to inhibit erythropoiesis. We conclude that serum hepcidin levels can predict the hematologic responsiveness to erythropoiesis-stimulating agent therapy in anemia of chronic disease. Pharmacological inhibition of hepcidin formation improves the erythropoiesis-stimulating agent's therapeutic efficacy, which may favor a reduction of erythropoiesis-stimulating agent dosages, costs and side effects.

Glomerular filtration rate in the elderly and in the oldest old: correlation with frailty and mortality

The equations for estimating kidney function have become very popular in the last decade. However, the clinical and prognostic meaning of these measures may be very different in older populations. Two cohorts of people aged 65-89 years (older sample) and 90 or more (oldest old sample) were used to investigate the prognostic significance of estimated glomerular filtration rate (eGFR). Additionally, we also investigated whether combining frailty and eGFR may improve the accuracy of frailty in predicting mortality. We found that lower eGFR values were significantly more frequent among frail subjects in both groups. eGFR < 30 was associated with increased risk for all-cause mortality either in subjects aged 65-89 years (HR = 3.71, 95% CI = 1.23-11.2) or in those aged 90 or more (HR = 1.53, 95% CI = 1.05-2.23). In the latter group, a not significant trend for increasing mortality was also observed among people with eGFR > 60 (HR = 1.28, 95% CI = 0.72-2.26). In addition, the oldest old subjects with eGFR > 60 and eGFR < 30 had the lowest hand-grip strength and ADL values. Combining eGFR and frailty status significantly improved the accuracy of frailty in predicting mortality only in the older sample. In conclusion, a U-shaped relationship exists between eGFR and mortality in the oldest old, but not in older individuals. Our findings suggest that eGFR needs to be adjusted for muscle mass/physical performance when estimating kidney function in people aged 90 or more. Nevertheless, in subjects aged 65-89 years, eGFR may improve the accuracy of frailty status in predicting prognosis, thus suggesting that eGFR may represent an additional dimension of frailty syndrome.

Effect of oral ferric citrate on serum phosphorus in hemodialysis patients: multicenter, randomized, double-blind, placebo-controlled study

BACKGROUND

Hyperphosphatemia is a common complication in dialysis patients that can be treated by oral phosphate binders. We investigated the efficacy and safety of oral ferric citrate as a phosphate binder for Taiwanese patients with end stage renal disease and with hyperphosphatemia who were undergoing hemodialysis.

METHODS

This was a prospective, double-blind, placebo-controlled, randomized trial carried out in 5 hospitals in Taiwan. Ferric citrate (4 or 6 g/day) or placebo was administered for 56 days. Serum calcium, phosphorous levels, calcium × phosphorus product, serum ferritin level, transferrin saturation, and adverse events were recorded.

RESULTS

A total of 166 patients completed the trial. The placebo group had relatively constant serum data. Serum phosphorus declined significantly in the 6 g/day group (p < 0.05 for 4 and 8 weeks) and the 4 g/day group (p < 0.05 for 4 and 8 weeks). There were similar changes in the calcium × phosphorus product. The serum ferritin level increased significantly in the 6 g/day group (p < 0.05) and the 4 g/day group (p < 0.05). There were similar changes in transferrin saturation. Most adverse events were mild to moderate and were comparable among the three groups.

CONCLUSIONS

A 56-day treatment with ferric citrate effectively controlled hyperphosphatemia and was well tolerated in maintenance hemodialysis patients. There were also moderate increases in serum ferritin and transferrin saturation.

Effect of systemic inflammation on level of ferritin seminal in chronic renal male patient undergoing hemodialysis

Background

Most hemodialysis patients present with chronic systemic inflammation characterized by the elevation of serum C-reactive protein (CRP) levels and/or the production of proinflammatory interleukins by the immune system in response to the hemodialysis process. Plasma ferritin(PF) is one of the parameters used to correct anemia. An PF level of >500 ng/mL is not recommended for correction of anemia because of the uncertainty of whether these levels are elevated because of anemia or a mere reaction to inflammation. we aimed to study the effects of inflammation on seminal ferritin (SF) levels and hypothesized that SF is not affected because of the testicular immune privilege.

Methods

A prospective prevalence study was conducted at the Department of Hemodialysis of the University Hospital of Brasília (HuB) between June 2010 and July 2011. The sample included 60 chronic renal patients undergoing hemodialysis and 20 control subjects from the health promotion general outpatient clinic. All participants were males aged 18–60 years. Inflammation was assessed through serum CRP levels, and the testicular condition was determined by measuring sex hormone levels. In the patient group, inflammation was considered to be present when CRP was >5 mg/L (n = 27) and absent when CRP was ≤5 mg/L (n = 33). Control group (n = 20) CRP was ≤1 mg/L. Blood and semen were collected via arm venoclysis and after voluntary masturbation, respectively. CRP was measured by turbidimetry; PF, SF, and sex hormone levels by immunochemoluminescence. Statistical significance was set at p < 0.05.

Results

There was no significant difference in mean SF levels among patients with inflammation (295.34 ± 145.39 ng/mL), those without inflammation (324.42 ± 145.51 mg/mL), and controls (335.70 ± 075.90 ng/mL; p = 0.49). There was no correlation between mean SF and PF levels in the patients with and without inflammation). All participants were eugonadal with mean serum FSH, LH, and testosterone levels of 3.76 ± 2.17 mUI/mL, 7.00 ± 3.53 mUI/mL, and 454.18 ± 173.08 ng/dL, respectively.

Conclusion

Systemic inflammation did not significantly alter SF levels in eugonadal hemodialysis patients.

Estimating glomerular filtration rate in older people

We aimed at reviewing age-related changes in kidney structure and function, methods for estimating kidney function, and impact of reduced kidney function on geriatric outcomes, as well as the reliability and applicability of equations for estimating glomerular filtration rate (eGFR) in older patients. CKD is associated with different comorbidities and adverse outcomes such as disability and premature death in older populations. Creatinine clearance and other methods for estimating kidney function are not easy to apply in older subjects. Thus, an accurate and reliable method for calculating eGFR would be highly desirable for early detection and management of CKD in this vulnerable population. Equations based on serum creatinine, age, race, and gender have been widely used. However, these equations have their own limitations, and no equation seems better than the other ones in older people. New equations specifically developed for use in older populations, especially those based on serum cystatin C, hold promises. However, further studies are needed to definitely accept them as the reference method to estimate kidney function in older patients in the clinical setting.

Anemia and iron deficiency in COPD patients: prevalence and the effects of correction of the anemia with erythropoiesis stimulating agents and intravenous iron

BACKGROUND

Little is known about iron deficiency (ID) and anemia in Chronic Obstructive Pulmonary Disease (COPD). The purposes of this study were: (i) To study the prevalence and treatment of anemia and ID in patients hospitalized with an exacerbation of COPD. (ii) to study the hematological responses and degree of dyspnea before and after correction of anemia with subcutaneous Erythropoiesis Stimulating Agents (ESAs) and intravenous (IV) iron therapy, in ambulatory anemic patients with both COPD and chronic kidney disease.

METHODS

(i) We examined the hospital records of all patients with an acute exacerbation of COPD (AECOPD) to assess the investigation, prevalence, and treatment of anemia and ID. (ii) We treated 12 anemic COPD outpatients with the combination of ESAs and IV-iron, given once weekly for 5 weeks. One week later we measured the hematological response and the severity of dyspnea by Visual Analogue Scale (VAS).

RESULTS

(i) Anemia and iron deficiency in hospitalized COPD patients: Of 107 consecutive patients hospitalized with an AECOPD, 47 (43.9%) were found to be anemic on admission. Two (3.3%) of the 60 non-anemic patients and 18 (38.3%) of the 47 anemic patients had serum iron, percent transferrin saturation (%Tsat) and serum ferritin measured. All 18 (100%) anemic patients had ID, yet none had oral or IV iron subscribed before or during hospitalization, or at discharge. (ii) Intervention outpatient study: ID was found in 11 (91.7%) of the 12 anemic ambulatory patients. Hemoglobin (Hb), Hematocrit (Hct) and the VAS scale scores increased significantly with the ESAs and IV-iron treatment. There was a highly significant correlation between the ∆Hb and ∆VAS; rs = 0.71 p = 0.009 and between the ∆Hct and ∆VAS; rs = 0.8 p = 0.0014.

CONCLUSIONS

ID is common in COPD patients but is rarely looked for or treated. Yet correction of the ID in COPD patients with ESAs and IV iron can improve the anemia, the ID, and may improve the dyspnea.

Renal Cell Protection of Erythropoietin beyond Correcting The Anemia in Chronic Kidney Disease Patients

Currently many patients with chronic renal failure have profited from the use of erythropoietin to correct anemia (1,2). In chronic kidney disease, anemia is believed to be a surrogate index for tissue hypoxia that continues preexisting renal tissue injury (1-3). Erythropoietin is an essential glycoprotein that accelerates red blood cell maturation from erythroid progenitors and facilitates erythropoiesis. It is a 30.4 kD glycoprotein and class I cytokine containing 165 amino acids (3,4). Approximately 90% of systemic erythropoietin in adults is produced by peritubular interstitial fibroblasts in the renal cortex and outer medulla of the kidney (3-5). A feedback mechanism involving oxygen delivery to the tissues seems to regulate erythropoietin production. Hypoxia-inducible factor regulates transcription of the erythropoietin gene in the kidney, which determines erythropoietin synthesis (3-5). Erythropoietin is an essential glycoprotein that accelerates red blood cell maturation from erythroid progenitors and mediates erythropoiesis in the bone marrow (4-6). Kidney fibrosis is the last common pathway in chronic renal failure irrespective of the initial etiology (5,6). Constant inflammatory cell infiltration and pericyte-myofibroblast transition lead to renal fibrosis and insufficiency which result in decreased production of erythropoietin (4-7). Thus far, therapeutic efforts to treat patients with chronic renal failure by administering erythropoietin have been made only to correct anemia and putative hypoxic tissue damage. The introduction of recombinant human erythropoietin has marked a significant advance in the management of anemia associated with chronic renal failure (6-9). With an increasing number of patients with chronic renal failure receiving erythropoietin treatment, emerging evidence suggests that erythropoietin not only has an erythropoietic function, but also has renoprotective potential. In fact, in recent years, the additional non-erythropoietic tissue/ organ protective efficacy of erythropoietin has become evident, especially in the kidneys (5-12). Various investigations have shown the kidney protective property of erythropoietin in acute kidney injury. In a study to evaluate the ameliorative effects of erythropoietin on renal tubular cells, we studied 40 male rats. We found that erythropoietin was able to prevent the increase in serum creatinine and blood urea nitrogen. Furthermore, co-administration of gentamicin and erythropoietin effectively reduced kidney tissue damage compared to the control group. However, the protective properties of erythropoietin were also evident in our study. When the drug was applied after gentamicin- induced tubular damage we were able to show that the drug was still effective after tissue injury onset. This indicates that erythropoietin may have curative effects in addition to its preventive properties (13). Thus, erythropoietin is a promising kidney protective agent to prevent, ameliorate or attenuate tubular damage induced by gentamicin or other nephrotoxic agents that act in a similar manner to this drug (14-17). Recent studies have elucidated the cellular mechanism involved in kidney erythropoietin production and the consequent events that lead to kidney fibrosis, showing that they are closely related to each other (18-20). In contrast to previous findings, fibroblasts originating from damaged renal tubular epithelial cells do not have an important role in kidney fibrosis, but renal erythropoietin- producing cells, stemming from neural crests, have been shown to trans-differentiate into myofibroblasts after long-term exposure to inflammatory situations related to kidney fibrosis. In fact, almost all myofibroblasts expressing α-smooth muscle actin originate from renal erythropoietin-producing cells, which are naturally peritubular interstitial fibroblastic cells expressing neural cell marker genes but not α-smooth muscle actin. Macrophages and myofibroblasts are responsible for fibrosis in the renal tissue. Macrophages could be differentiated to phenotype M1 (classically activated) or M2 (wound healing) according to the distinctive cytokine production and behavior that follows different routes of activation (6,8,21,22). While erythropoietin can disengage macrophages by stopping the activity of NF-κB, it is possible that one of the mechanisms explaining the antifibrotic effects of erythropoietin in chronic kidney disease is in vivo macrophage regulation (20-25). These important findings stipulate the missing link in chronic renal failure between anemia and kidney fibrosis (6,8,21,22). In patients with chronic kidney disease, anemia due to reduced erythropoietin production eventually appears (1,4,5). Recombinant human erythropoietin has been used for more than 20 years in chronic kidney disease to recompense for reduced endogenous erythropoietin production (1,4,5,25). Recent investigations have pointed out that erythropoietin administration improves kidney functions in chronic kidney disease either directly or indirectly (17-24). The therapeutic benefits of erythropoietin beyond the correction of anemia are still questioned. However, it is notable that various pieces of evidence simply reflect the pleiotropic effects of erythropoietinon on the central nervous, cardiovascular system and on the kidney (18,20,25). In brief, clinical evidence shows the kidney protective potential of erythropoietin in patients with chronic renal failure, however, additional clinical investigations are crucial to outline when to start erythropoietin treatment and what is the optimal erythropoietin dosage for slowing disease progression in patients with chronic renal failure. The application of erythropoietin treatment for renoprotection may need to be earlier than that for erythropoiesis, while it is possible that the erythropoietin attenuation of renal fibrosis through macrophage regulation and endothelial cell protection operates through other unidentified mechanisms. While agents restoring the initial function of renal erythropoietin-producing cells could delay kidney fibrosis, further laboratory studies are necessary to clarify the cellular target of erythropoietin in the kidney and for developing a novel erythropoietin derivative or mimetic for kidney protection.

Clinical impact of hospital-acquired anemia in association with acute kidney injury and chronic kidney disease in patients with acute myocardial infarction

Background

Hospital-acquired anemia (HAA) is common in patients with acute myocardial infarction (AMI) and is an independent indicator of long-term mortality in these patients. However, limited information exists regarding the development and prognostic impact of HAA associated with acute kidney injury (AKI) and chronic kidney disease (CKD) in AMI patients.

Methods and Results

We retrospectively analyzed 2,289 patients with AMI, and excluded those with anemia at admission. The study population included 1,368 patients, of whom 800 (58.5%) developed HAA. Age, Hgb level at admission, Length of hospital stay, documented in-hospital bleeding and use of glycoprotein IIb/IIIa inhibitor, presence of CKD and occurrence of AKI were significantly associated with the development of HAA. HAA was significantly associated with higher 3-year mortality (4.8% and 11.4% for non-HAA and HAA patients, respectively; P < 0.001). After adjustment for multivariable confounders, the risk for long-term mortality was increased in HAA patients with AKI and/or CKD but not in HAA patients without AKI and/or CKD, compared to non-HAA patients (HAA patients without AKI and CKD, hazard ratio [HR]: 1.34, 95% confidence interval [CI]: 0.70–2.56; HAA patients with either AKI or CKD, HR: 2.80, 95% CI: 1.37–5.73; HAA patients with AKI and CKD, HR: 3.25, 95% CI: 1.28–8.24; compared with the non-HAA group).

Conclusion

AKI and CKD were strongly associated with the development of HAA in AMI patients. HAA, when accompanied by AKI or CKD, is an independent risk predictor for long-term mortality in AMI patients.

Feline CKD: New horizons - where do we go from here?

PRACTICAL RELEVANCE

Chronic kidney disease (CKD) is common in humans as well as in cats, and is a significant human health problem. In feline medicine, despite recent research and improvements in our understanding of the condition, management remains limited by late diagnosis and an inadequate ability to prevent progression of disease. Investigation of future treatments that both delay the progression of CKD and manage clinical signs, and that are also easy and cost effective to administer, is desirable. To this end, we may learn from our colleagues in the medical profession.

AUDIENCE

CKD is commonly encountered in general practice and so all practitioners dealing with cats will benefit from understanding future treatment possibilities and interventions in the management of CKD.

EVIDENCE BASE

Large-scale medical studies have been performed to provide an evidence base for treatment decisions in human CKD. Several studies in cats have looked at various aspects of treatment and prognosis, but large-scale studies are needed to assess the benefits of treatments such as angiotensin-converting enzyme inhibitors and angiotensin receptor blockers.

CLINICAL CHALLENGES

Providing treatment that is effective, easy to administer and not cost-prohibitive is the challenge currently faced by clinicians in the management of feline CKD.

The A736V TMPRSS6 polymorphism influences hepcidin and iron metabolism in chronic hemodialysis patients: TMPRSS6 and hepcidin in hemodialysis

BACKGROUND

Aim of this study was to evaluate whether the A736V TMPRSS6 polymorphism, a major genetic determinant of iron metabolism in healthy subjects, influences serum levels of hepcidin, the hormone regulating iron metabolism, and erythropoiesis in chronic hemodialysis (CHD).

METHODS

To this end, we considered 199 CHD patients from Northern Italy (157 with hepcidin evaluation), and 188 healthy controls without iron deficiency, matched for age and gender. Genetic polymorphisms were evaluated by allele specific polymerase chain reaction assays, and hepcidin quantified by mass spectrometry.

RESULTS

Serum hepcidin levels were not different between the whole CHD population and controls (median 7.1, interquartile range (IQR) 0.55-17.1 vs. 7.4, 4.5-17.9 nM, respectively), but were higher in the CHD subgroup after exclusion of subjects with relative iron deficiency (p = 0.04). In CHD patients, the A736V TMPRSS6 polymorphism influenced serum hepcidin levels in individuals positive for mutations in the HFE gene of hereditary hemochromatosis (p < 0.0001). In particular, the TMPRSS6 736 V variant was associated with higher hepcidin levels (p = 0.017). At multivariate analysis, HFE and A736V TMPRSS6 genotypes predicted serum hepcidin independently of ferritin and C reactive protein (p = 0.048). In patients without acute inflammation and overt iron deficiency (C reactive protein <1 mg/dl and ferritin >30 ng/ml; n = 86), hepcidin was associated with lower mean corpuscular volume (p = 0.002), suggesting that it contributed to iron-restricted erythropoiesis. In line with previous results, in patients without acute inflammation and severe iron deficiency the "high hepcidin" 736 V TMPRSS6 variant was associated with higher erythropoietin maintenance dose (p = 0.016), independently of subclinical inflammation (p = 0.02).

CONCLUSIONS

The A736V TMPRSS6 genotype influences hepcidin levels, erythropoiesis, and anemia management in CHD patients. Evaluation of the effect of TMPRSS6 genotype on clinical outcomes in prospective studies in CHD may be useful to predict the outcomes of hepcidin manipulation, and to guide treatment personalization by optimizing anemia management.

Regulation of erythropoiesis by hypoxia-inducible factors

A classic physiologic response to systemic hypoxia is the increase in red blood cell production. Hypoxia-inducible factors (HIFs) orchestrate this response by inducing cell-type specific gene expression changes that result in increased erythropoietin (EPO) production in kidney and liver, in enhanced iron uptake and utilization and in adjustments of the bone marrow microenvironment that facilitate erythroid progenitor maturation and proliferation. In particular HIF-2 has emerged as the transcription factor that regulates EPO synthesis in the kidney and liver and plays a critical role in the regulation of intestinal iron uptake. Its key function in the hypoxic regulation of erythropoiesis is underscored by genetic studies in human populations that live at high-altitude and by mutational analysis of patients with familial erythrocytosis. This review provides a perspective on recent insights into HIF-controlled erythropoiesis and iron metabolism, and examines cell types that have EPO-producing capability. Furthermore, the review summarizes clinical syndromes associated with mutations in the O(2)-sensing pathway and the genetic changes that occur in high altitude natives. The therapeutic potential of pharmacologic HIF activation for the treatment of anemia is discussed.