Renal anemia of inflammation: the name is self-explanatory

Anemia of Chronic Kidney Disease-A Narrative Review of Its Pathophysiology, Diagnosis, and Management

Anemia is one of the most common chronic kidney disease (CKD) complications. It negatively affects patients' quality of life and clinical outcomes. The pathophysiology of anemia in CKD involves the interplay of various factors such as erythropoietin (EPO) deficiency, iron dysregulation, chronic inflammation, bone marrow dysfunction, and nutritional deficiencies. Despite recent advances in understanding this condition, anemia still remains a serious clinical challenge in population of patients with CKD. Several guidelines have been published with the aim to systematize the diagnostic approach and treatment of anemia; however, due to emerging data, many recommendations vary between publications. Recent studies indicate a potential of novel biomarkers to evaluate anemia and related conditions such as iron deficiency, which is often present in CKD patients. Our article aims to summarize the pathophysiology of anemia in CKD, as well as the diagnosis and management of this condition, including novel therapeutic approaches such as hypoxia-inducible factor-prolyl hydroxylase inhibitors (HIF-PHI). Understanding these complex subjects is crucial for a targeted approach to diagnose and treat patients with anemia in CKD effectively.

Quantitative systems pharmacology model of erythropoiesis to simulate therapies targeting anemia due to chronic kidney disease

Anemia induced by chronic kidney disease (CKD) has multiple underlying mechanistic causes and generally worsens as CKD progresses. Erythropoietin (EPO) is a key endogenous protein which increases the number of erythrocyte progenitors that mature into red blood cells that carry hemoglobin (Hb). Recombinant human erythropoietin (rHuEPO) in its native and re-engineered forms is used as a therapeutic to alleviate CKD-induced anemia by stimulating erythropoiesis. However, due to safety risks associated with erythropoiesis-stimulating agents (ESAs), a new class of drugs, prolyl hydroxylase inhibitors (PHIs), has been developed. Instead of administering exogenous EPO, PHIs facilitate the accumulation of HIF-α, which results in the increased production of endogenous EPO. Clinical trials for ESAs and PHIs generally involve balancing decisions related to safety and efficacy by carefully evaluating the criteria for patient selection and adaptive trial design. To enable such decisions, we developed a quantitative systems pharmacology (QSP) model of erythropoiesis which captures key aspects of physiology and its disruption in CKD. Furthermore, CKD virtual populations of varying severities were developed, calibrated, and validated against public data. Such a model can be used to simulate alternative trial protocols while designing phase 3 clinical trials, as well as an asset for reverse translation in understanding emerging clinical data.

The association of hepcidin, reticulocyte hemoglobin equivalent and anemia-related indicators on anemia in chronic kidney disease

Hepcidin is an essential regulator of iron homeostasis in chronic kidney disease (CKD) anemia, reticulocyte hemoglobin equivalent (RET-He) can be used to evaluate the availability of iron for erythropoiesis. Previous research has found that hepcidin indirectly regulates RET-He. This study aimed to investigate the association of hepcidin, RET-He and anemia-related indicators on anemia in chronic kidney disease. A total of 230 individuals were recruited, including 40 CKD3-4 patients, 70 CKD5 patients without renal replacement therapy, 50 peritoneal dialysis patients, and 70 hemodialysis patients. The serum levels of hemoglobin (Hb), reticulocyte, RET-He, serum iron, serum creatinine, serum ferritin, total iron binding capacity, hepcidin-25, high sensitivity C-reactive protein, transferrin, erythropoietin, intrinsic factor antibody, soluble transferrin receptor and interleukins-6 (IL-6) were measured. Hepcidin-25 was positively associated with IL-6, and negatively with total iron binding capacity, intrinsic factor antibody, and transferrin. Reticulocyte Hb equivalent was associated positively with Hb, serum ferritin, serum iron, transferrin saturation, and negatively with serum creatinine, reticulocyte, IL-6, STfR. Hepcidin-25 was not associated with RET-He, while IL-6 was independently associated with hepcidin-25 and RET-He, suggesting that hepcidin has no effffect on the iron dynamics of reticulocytes in CKD, may be related to IL-6, indicate a likelihood of a threshold for stimulation of hepcidin-25 expression by IL-6 in order to indirectly regulates RET-He.

Hypoxia-inducible factor signaling in vascular calcification in chronic kidney disease patients

Chronic kidney disease (CKD) affects approximately 15% of the adult population in high-income countries and is associated with significant comorbidities, including increased vascular calcifications which is associated with a higher risk for cardiovascular events. Even though the underlying pathophysiology is unclear, hypoxia-inducible factor (HIF) signaling appears to play a central role in inflammation, angiogenesis, fibrosis, cellular proliferation, apoptosis and vascular calcifications which is influenced by multiple variables such as iron deficiency anemia, serum phosphorus and calcium levels, fibroblast growth factor-23 (FGF-23) and Klotho. Along with the growing understanding of the pathology, potential therapeutic alternatives have emerged including HIF stabilizers and SGLT-2 inhibitors. The aim of this review is to discuss the role of HIF signaling in the pathophysiology of vascular calcification in CKD patients and to identify potential therapeutic approaches.

The role of iron in chronic inflammatory diseases: from mechanisms to treatment options in anemia of inflammation

Anemia of inflammation (AI) is a highly prevalent comorbidity in patients affected by chronic inflammatory disorders, such as chronic kidney disease, inflammatory bowel disease, or cancer, that negatively affect disease outcome and quality of life. The pathophysiology of AI is multifactorial, with inflammatory hypoferremia and iron-restricted erythropoiesis playing a major role in the context of disease-specific factors. Here, we review the recent progress in our understanding of the molecular mechanisms contributing to iron dysregulation in AI, the impact of hypoferremia and anemia on the course of the underlying disease, and (novel) therapeutic strategies applied to treat AI.

Exploring the lived experience of renal cachexia for individuals with end-stage renal disease and the interrelated experience of their carers: Study protocol

Renal cachexia is an important consideration in the person-centred care that is needed in end-stage renal disease (ESRD). However, given that clinical guidelines relating to renal cachexia are largely absent, this is an unmet care need. To inform guidelines and future renal service planning, there is an urgency to understand individuals’ experiences of renal cachexia and the interrelated experiences of the carers in their lives. We report here the protocol for an interpretative phenomenological study which will explore this lived experience. A purposive sampling strategy will recruit individuals living with ESRD who have cachexia and their carers. A maximum of 30 participants (15 per group) dependent on saturation will be recruited across two nephrology directorates, within two healthcare trusts in the United Kingdom. Individuals with renal cachexia undergoing haemodialysis will be recruited via clinical gatekeepers and their carers will subsequently be invited to participate in the study. Participants will be offered the opportunity to have a face-to-face, virtual or telephone interview. Interviews will be audio-recorded, transcribed verbatim and analysed using interpretative phenomenological analysis. NVivo, will be used for data management. Ethical approval for this study was granted by the Office for Research Ethics Committees Northern Ireland (REC Reference: 22/NI/0107). Scientific evidence tends to focus on measurable psychological, social and quality of life outcomes but there is limited research providing in-depth meaning and understanding of the views of individuals with renal disease who are experiencing renal cachexia. This information is urgently needed to better prepare healthcare providers and in turn support individuals with ESRD and their carers. This study will help healthcare providers understand what challenges individuals with ESRD, and their carers face in relation to cachexia and aims to inform future clinical practice guidelines and develop supportive interventions which recognise and respond to the needs of this population.

Tetramethylpyrazine nitrone activates hypoxia-inducible factor and regulates iron homeostasis to improve renal anemia

Renal anemia is one of the most common complications of chronic kidney disease and diabetic kidney disease. Despite the progress made in recent years, there is still an urgent unmet clinical need for renal anemia treatment. In this research, we investigated the efficacy and mechanism of action of the novel tetramethylpyrazine nitrone (TBN). Animal models of anemia including the streptozotocin (STZ)-induced spontaneously hypertensive rats (SHR) and the cisplatin (CDDP)-induced C57BL/6J mice are established to study the TBN's effects on expression of hypoxia-inducible factor and erythropoietin. To explore the mechanism of TBN's therapeutic effect on renal anemia, cobalt chloride (CoCl2) is used in Hep3B/HepG2 cells to simulate a hypoxic environment. TBN is found to increase the expression of hypoxia-inducible factor HIF-1α and HIF-2α under hypoxic conditions and reverse the reduction of HIFs expression caused by saccharate ferric oxide (SFO). TBN also positively regulates the AMPK pathway. TBN stimulates nuclear transcription and translation of erythropoietin by enhancing the stability of HIF-1α expression. TBN has a significant regulatory effect on several major biomarkers of iron homeostasis, including ferritin, ferroportin (FPN), and divalent metal transporter-1 (DMT1). In conclusion, TBN regulates the AMPK/mTOR/4E-BP1/HIFs pathway, and activates the hypoxia-inducible factor and regulates iron homeostasis to improve renal anemia.

Association between Body Mass Index and Renal Outcomes Modified by Chronic Kidney Disease and Anemia: The Obesity Paradox for Renal Outcomes

Obesity-related nephropathy is associated with renal function progression. However, some studies have associated a high body mass index (BMI) with improved renal outcomes—this is referred to as the obesity paradox for renal outcomes, especially in relation to advanced chronic kidney disease (CKD). Central obesity can explain the obesity paradox in all-cause mortality. However, whether obesity or central obesity is associated with renal outcomes (renal replacement therapy or a 50% decline in the estimated glomerular filtration rate) in patients with advanced CKD remains unclear. Our study included 3605 Asian patients with CKD stages 1−5 divided into six groups according to their BMI (between 15 and 35 kg/m2). Through linear regression, BMI was positively associated with hemoglobin and albumin at CKD stages 4 and 5. In the competing risk Cox regression model, a high BMI (27.5−35 kg/m2) was associated with renal outcomes at CKD stages 1−3, but not stages 4 and 5. A high BMI was associated with renal outcomes in patients with hemoglobin ≥11 g/dL, but not <11 g/dL. A high waist-to-hip ratio was not associated with renal outcomes. We conclude that the CKD stage and anemia may explain the obesity paradox in renal outcomes in patients with CKD.

Efficacy and safety of darbepoetin alfa injection replacing epoetin alfa injection for the treatment of renal anemia in Chinese hemodialysis patients: A randomized, open‐label, parallel‐group, noninferiority phase III trial

Background

This study was to explore the clinical efficacy and safety of darbepoetin alfa injection replacing epoetin alfa injection (recombinant human erythropoietin injection, rHuEPO) for the treatment of anemia associated with chronic kidney failure in Chinese patients undergoing hemodialysis.

Method

This study was a multicenter, randomized, open‐label, intergroup parallel control phase III noninferiority trial from April 19, 2013 to September 9, 2014 at 25 sites. In this study, the members of the darbepoetin alfa group underwent intravenous administration once per week or once every two weeks. The members of the control drug epoetin alfa group underwent intravenous administration two or three times per week. All subjects underwent epoetin alfa administration during the 8‐week baseline period. After that, subjects were randomly assigned to the darbepoetin alfa group or epoetin alfa group. The noninferiority in the changes of the average Hb concentrations from the baseline to the end of the evaluation period (noninferiority threshold: −1.0 g/dl) was tested between the two treatments. The time‐dependent hemoglobin (Hb) concentration and the maintenance rate of the target Hb concentration (the proportion of subjects with Hb concentrations between 10.0 and 12.0 g/dl) were also evaluated. Iron metabolism, including changes in the serum iron, total iron‐binding capacity, ferritin, transferrin saturation, and comparisons of the dose adjustments between the two groups during the treatment period were analyzed further. Adverse events (AEs) were also observed and compared, and the safety was analyzed between the two treatment groups. The conversion rate switching from epoetin alfa to darbepoetin alfa was also discussed. SAS® software version 9.2 was used to perform all statistical analyses. Descriptive statistics were used for all efficacy, safety, and demographic variable analyses, including for the primary efficacy indicators.

Results

Four hundred and sixty‐six patients were enrolled in this study, and ultimately 384 cases were analyzed for safety, including 267 cases in the darbepoetin alfa group and 117 cases in the epoetin alfa group. There were 211 cases in the per‐protocol set, including 152 cases in the darbepoetin alfa group and 59 cases in the epoetin alfa group. The changes in the average Hb concentrations from the baseline to the end of the evaluation period were −0.07 and −0.15 g/dl in the darbepoetin alfa group and epoetin alfa group respectively. The difference between the two groups was 0.08 g/dl (95% confidence interval [CI]: −0.22 to 0.39), and the lower limit of the 95% CI was −0.22 > −1.0 g/dl. The average Hb concentrations of the two groups were 10.88–11.43 g/dl (darbepoetin alfa) and 10.91–11.38 g/dl (epoetin alfa) during the study period of Weeks 0–28, with the maintenance rates of the target Hb concentration ranging within 71%–87% and 78%–95% in the darbepoetin alfa group and epoetin alfa group respectively. During the period of comparison between the two groups, the incidence of AEs in the darbepoetin alfa group was 61.42%, while in the epoetin alfa group it was 56.41%. All of the adverse events and reactions in the study were those commonly associated with hemodialysis.

Conclusion

The overall efficacy and safety of darbepoetin alfa for the treatment of Chinese renal anemia patients undergoing hemodialysis are consistent with those of epoetin alfa.

Efficacy and safety of darbepoetin alfa are good for Chinese renal anemia patients.

Efficacy and safety of darbepoetin alfa are consistent with those of epoetin alfa.

Darbepoetin alfa is convenient in clinical use due to the low frequency of dose adjustment.

Iron Overload in Chronic Kidney Disease: Less Ferritin, More T2*MRI

To date, there is no consensus on the most reliable marker of iron status in patients with chronic kidney disease (CKD). Serum ferritin is used routinely, although it may be a misleading marker for iron overload. The success of T2^* MRI in monitoring iron overload in patients with hemoglobinopathies can be beneficial to monitoring patients with CKD.

A Prospective, Self-Controlled Pilot Study of the Efficacy of Roxadustat for Erythropoietin Hyporesponsiveness in Patients Requiring Chronic Ambulatory Peritoneal Dialysis

OBJECTIVES

The present study aimed to explore the efficacy and safety of roxadustat in patients with renal anemia and erythropoietin (EPO) hyporesponsive who are receiving continuous ambulatory peritoneal dialysis (CAPD).

METHODS

This is a single center, before and after treatment, self-controlled study; 55 CAPD patients with renal anemia and EPO hyporesponsiveness were enrolled. The main follow-up parameters included routine blood, liver and kidney function, electrolyte, blood lipid, high-sensitivity C-reactive protein, and iron tests. Serum samples were used to determine interleukin-6 and tumor necrosis factor-α levels via enzyme linked immunosorbent assay. The Modified Quantitative Subjective Global Assessment Score and Malnutrition-Inflammation Score before and after treatment, and adverse events during treatment were recorded. The follow-up observation time was 12 weeks. Preliminary data 12-24 weeks before the enrollment as well as post-follow-up data at 36 weeks were also collected.

RESULTS

Fifty patients completed the 12-week follow-up. The hemoglobin levels were 8.0 ± 1.2 g/dL at baseline and 11.2 ± 2.0 g/dL after 12 weeks of roxadustat treatment. The hemoglobin increases at all measured time points and was statistically significant compared with the baseline value (P < .05). The overall hemoglobin response rate (hemoglobin increase ≥ 1.0 g/dL) was 80%, and 50% of the patients reached the hemoglobin target (hemoglobin ≥ 11.0 g/dL) at 12 weeks. Transferrin was higher at 12 weeks (2.2 ± 0.5 g/L) than at baseline (1.7 ± 0.5 g/L) (P < .05), while serum ferritin levels slightly decreased compared with the baseline value (P > .05). The median high-sensitivity C-reactive protein level and other inflammation-related indicators, such as white blood cell counts, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, interleukin-6, and tumor necrosis factor-α, were not significantly different from their baseline values. Nutrition-related biochemical indices such as albumin, creatinine, and blood lipids were also not significantly changed. The Modified Quantitative Subjective Global Assessment Score and Malnutrition-Inflammation Score were slightly lower at 12 weeks than at baseline. No serious adverse events were observed during the follow-up period. Post-follow-up data revealed a maintained hemoglobin level in patients who remained on roxadustat treatment while those switched back to EPO treatment after 12 weeks resulted in a decreased hemoglobin at 36 weeks.

CONCLUSIONS

In patients with EPO hyporesponsiveness on CAPD, roxadustat can efficiently and safely improve anemia and nutritional status without promoting inflammation.

Efficacy and Safety of Molidustat for Anemia in ESA-Naive Nondialysis Patients: A Randomized, Phase 3 Trial

INTRODUCTION

Molidustat is an oral hypoxia-inducible factor prolyl hydroxylase inhibitor that predominantly induces renal production of erythropoietin (EPO). Molidustat was evaluated for the treatment of anemia associated with chronic kidney disease (CKD) in the "Molidustat Once Daily Improves Renal Anemia by Inducing EPO" (MIYABI) program, which comprises 5 phase 3 clinical trials. The present MIYABI Non-Dialysis Correction (ND-C) study investigated the efficacy and safety of molidustat in Japanese patients with renal anemia who were not undergoing dialysis and were not receiving erythropoiesis-stimulating agent (ESA) treatment.

METHODS

This was a 52-week, randomized (1:1), open-label, active-control, parallel-group, multicenter, phase 3 study in Japanese patients with renal anemia associated with CKD (stages 3-5). Molidustat or the ESA darbepoetin alfa (hereinafter referred to as darbepoetin) were initiated at 25 mg once daily or 30 μg every 2 weeks, respectively, and doses were regularly titrated to correct and to maintain hemoglobin (Hb) levels in the target range of ≥11.0 g/dL and <13.0 g/dL. The primary efficacy outcome was the mean Hb level and its change from baseline during the evaluation period (weeks 30-36). The safety outcomes included evaluation of all adverse events.

RESULTS

In total, 162 patients were randomized to receive molidustat (n = 82) or darbepoetin (n = 80). Baseline characteristics were generally well balanced between treatment groups. The mean (standard deviation) Hb levels at baseline were 9.84 (0.64) g/dL for molidustat and 10.00 (0.61) g/dL for darbepoetin. The mean (95% confidence interval [CI]) for mean Hb levels during the evaluation period for molidustat (11.28 [11.07, 11.50] g/dL) and darbepoetin (11.70 [11.50, 11.90] g/dL) was within the target range. Based on a noninferiority margin of 1.0 g/dL, molidustat was noninferior to darbepoetin in the change in mean Hb level during the evaluation period from baseline; the least-squares mean (95% CI) difference (molidustat-darbepoetin) was -0.38 (-0.67, -0.08) g/dL. The proportion of patients who reported at least 1 treatment-emergent adverse event (TEAE) was 93.9% for molidustat and 93.7% for darbepoetin. Most TEAEs were mild (54.9% for molidustat and 63.3% for darbepoetin) or moderate (22.0% for molidustat and 22.8% for darbepoetin) in intensity. There were 3 deaths in the molidustat group and 1 in the darbepoetin group.

DISCUSSION/CONCLUSION

In the MIYABI ND-C study, molidustat appeared to be an efficacious and generally well-tolerated alternative to darbepoetin for the treatment of renal anemia in Japanese patients who were not undergoing dialysis and were not receiving ESA treatment.

Prolyl Hydroxylase Inhibitors: a New Opportunity in Renal and Myocardial Protection

Hypoxia, via the activity of hypoxia-inducible factors (HIFs), plays a crucial role in fibrosis, inflammation, and oxidative injury, processes which are associated with progression of cardiovascular and kidney diseases. HIFs are key transcription heterodimers consisting of regulatory α-subunits (HIF-1α, HIF-2α, HIF-3α) and a constitutive β-subunit (HIF-β). The stability of HIFs is regulated by the prolyl hydroxylases (PHDs). Specific PHD inhibitors (PHD-i) are being investigated as a therapeutic approach to modulate the cellular signaling pathways and harness the native protective adaptive responses to hypoxia. Selective inhibition of PHD leads to the stabilization of the HIFs, which is the transcriptional gatekeeper of a multitude of genes involved in angiogenesis, energy metabolism, apoptosis, inflammation, and fibrosis. PHD-i downregulate hepcidin, improve iron absorption, and increase the endogenous production of erythropoietin. Furthermore, this pharmacological group has also been proven to ameliorate ischemic injuries in several organs, opening a new and promising field in cardiovascular research.. In this review, we present the basic and clinical potential of PHD-i treatment in different scenarios, such as ischemic heart disease, cardiac hypertrophy and heart failure, and their interplay with other pharmacological agents with proven cardiovascular benefits, such as sodium-glucose cotransporter 2 (SGLT2) inhibitors.

Effect of sodium-glucose cotransporter 2 inhibitors on hemoglobin and hematocrit levels in type 2 diabetes: a systematic review and meta-analysis

BACKGROUND

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) improve outcomes of patients with type 2 diabetes at high cardiovascular risk and chronic kidney disease. Recent studies showed an increase in hemoglobin and hematocrit after SGLT2i treatment.

MATERIALS AND METHODS

We did a systematic review and meta-analysis of randomized, double-blind, placebo-controlled studies of SGLT2i in patients with type 2 diabetes. We searched through PubMed/Medline, Web of Science, Embase (Elsevier), and the Cochrane Central Register of Controlled Trials (Wiley) from January 2010 to January 2021.

RESULTS

We included seventeen randomized, double-blind, placebo-controlled studies. The total number of evaluated patients was 14,748. The treatment arm consisted of canagliflozin, dapagliflozin, empagliflozin and ipragliflozin. SGLT2i therapy significantly increased hemoglobin levels when compared to placebo (MD 5.60 g/L, 95% CI 3.73-7.47 g/L, P < 0.00001, considerable heterogeneity-I² = 94%). Each SGLT2i also led to a significant increase in the hematocrit level when compared to placebo (MD 1.32%, 95% CI 1.21-1.44, P < 0.00001, considerable heterogeneity-I² = 99%).

CONCLUSIONS

SGLT2i led to significant increases in hemoglobin and hematocrit levels when compared to placebo. In addition to their cardiovascular effect, SGLT2i also increases hemoglobin and hematocrit levels.

Mean corpuscular hemoglobin concentration: an anemia parameter predicting cardiovascular disease in incident dialysis patients

BACKGROUND

Hemoglobin levels usually decline before dialysis initiation. The influence of overhydration on anemia progression and iron sequestration is poorly documented. Furthermore, clinical implications of anemia at dialysis initiation remain to be elucidated.

METHODS

This multicenter retrospective cohort study enrolled incident dialysis patients. The patients were stratified by tertiles of overhydration rate (OH-R) defined by (BW - DW)/DW*100 (BW: body weight just before dialysis initiation, DW: dry weight). Time courses (6 months before, to 1 month after, dialysis initiation) of hemoglobin, C-reactive protein (CRP), and iron sequestration index (ISI) were examined using mixed effects models. We used Cox models to identify anemia parameters predicting subsequent cardiovascular disease (CVD).

RESULTS

Among the 905 enrolled patients, hemoglobin levels gradually decreased before dialysis initiation and rapidly increased thereafter. An inverse V-shaped time course was observed for CRP and ISI with an increase during dialysis initiation. Patients with a higher OH-R showed lower hemoglobin levels along with higher CRP and ISI levels before dialysis initiation. Mean corpuscular hemoglobin concentration (MCHC) was more stable before dialysis initiation than were mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH). Low MCHC (< 32 g/dL) was independently associated with the incidence of nonatherosclerotic CVD. Patients with low MCHC tended to have increased left ventricular wall thickness and left atrial diameter.

CONCLUSIONS

Progression of anemia before dialysis among overhydrated patients may mainly occur through hemodilution and iron sequestration partly induced by inflammation. Low MCHC reflects left atrial overload and left ventricular hypertrophy and hence may predict nonatherosclerotic CVD.

Multifaceted Sexual Dysfunction in Dialyzing Men and Women: Pathophysiology, Diagnostics, and Therapeutics

Patient survival continues to increase with the growing quality of dialysis and management of chronic kidney disease (CKD). As such, chronic therapy must include considerations of quality of life (QOL), and this includes the disproportionate prevalence of sexual dysfunction (SD) in this patient population. This review aims to describe the pathophysiological and the psychosocial causes of SD with regard to renal replacement therapy, particularly hemo- and peritoneal dialysis. The differences in its manifestation in men and women are compared, including hormonal imbalances—and therefore fertility, libido, and sexual satisfaction—the experience of depression and anxiety, and QOL. The impact of comorbidities and the iatrogenic causes of SD are described. This review also presents validated scales for screening and diagnosis of SD in CKD patients and outlines novel therapies and strategies for the effective management of SD. Increased prevalence of CKD invariably increases the number of patients with SD, and it is crucial for health care professional teams to become familiar with the clinical tools used to manage this sensitive and under-quantified field. As a known predictor of QOL, sexual function should become a point of focus in the pursuit of patient-centered care, particularly as we seek to achieve as “normal” a life as possible for individuals who receive dialysis.

Effect of Moderate Hepatic Impairment on the Pharmacokinetics of Vadadustat, an Oral Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitor

Vadadustat is a hypoxia-inducible factor prolyl hydroxylase inhibitor in development for the treatment of anemia of chronic kidney disease. This phase 1, open-label, parallel-group, single-dose study evaluated the pharmacokinetics of 450-mg vadadustat in adults with moderate hepatic impairment (Child-Pugh class B) vs those with normal hepatic function. Primary end points were area under the plasma concentration-time curve (AUC) from dosing to last concentration and to infinity, as well as maximum concentration (C_max ); additional pharmacokinetic parameters included time to C_max (T_max ) and half-life. Safety and tolerability were also assessed. All enrolled participants (n = 16) completed the study. Demographics were similar in both groups (overall, 100% White; 62.5% female; mean age, 59.2 years). Vadadustat plasma exposure was higher in the moderate hepatic impairment group, whereas maximum concentration was similar between groups. Point estimates of the hepatic impairment : normal geometric mean ratios (90% confidence interval) for AUC from dosing to last concentration, AUC from dosing to infinity, and C_max were 1.05 (0.82-1.35), 1.06 (0.82-1.36), and 1.02 (0.79-1.32), respectively. Mean elimination half-life was 5.8 and 7.8 hours in the normal and hepatic impairment groups, respectively. Treatment-emergent adverse events were mostly mild in severity, and vadadustat was generally well tolerated. In conclusion, moderate hepatic impairment did not significantly impact vadadustat systemic exposure, and mild hepatic impairment is unlikely to alter vadadustat exposure.

Effect of Probiotic, Prebiotic, and Synbiotic Supplementation on Cardiometabolic and Oxidative Stress Parameters in Patients With Chronic Kidney Disease: A Systematic Review and Meta-analysis

PURPOSE

Chronic kidney disease (CKD) is a major health problem worldwide. Evidence supporting the use of probiotic, prebiotic, and synbiotic supplementation in the management of CKD is mixed, although some studies suggest they may be useful. A systematic review and meta-analysis was performed to evaluate the effectiveness of probiotic, prebiotic, and synbiotic supplementation for improving cardiometabolic and oxidative stress parameters in patients with CKD.

METHODS

A comprehensive key word search was performed in EMBASE, Medline, Scopus, Cochrane Central, and Web of Science until April 2020. Randomized controlled trials investigating the effectiveness of probiotic, synbiotic, and prebiotic supplementation for the management of adults with CKD were included. Primary outcomes were measures of cardiometabolic parameters such as cholesterol and fasting blood glucose. Secondary outcomes were measures of oxidative stress (eg, malondialdehyde levels) and body mass index. Random effects meta-analyses were used to estimate mean treatment effects. Results are reported as standardized mean differences (SMDs) and 95% CIs.

FINDINGS

Fourteen articles were included. In patients with CKD, probiotic, prebiotic, and synbiotic supplementation significantly reduced total cholesterol (SMD, -0.25; 95% CI, -0.46 to -0.04; I² = 00.0%), fasting blood glucose (SMD, -0.41; 95% CI, -0.65 to -0.17; I² = 00.0%), homeostatic model assessment of insulin resistance (SMD, -0.63; 95% CI, -0.95 to -0.30; I² = 43.3%), insulin levels (SMD, -0.49; 95% CI, -0.90 to -0.08; I² = 65.2%), high-sensitivity C-reactive protein levels (SMD, -0.52; 95% CI, -0.81 to -0.22; I² = 52.7%), and malondialdehyde levels (SMD, -0.79; 95% CI, -1.22 to -0.37; I² = 69.8%) compared with control interventions. Supplementation significantly increased the quantitative insulin sensitivity check index (SMD, 0.78; 95% CI, 0.51 to 1.05; I² = 00.0%), total antioxidant capacity (SMD, 0.42; 95% CI, 0.18 to 0.66; I² = 00.0%), and glutathione levels (SMD, 0.52; 95% CI, 0.19 to 0.86; I² = 37.0%).

IMPLICATIONS

Probiotic, prebiotic, and synbiotic supplementation seems to be a promising intervention for improving cardiometabolic and oxidative stress parameters in patients with CKD.

Iron Therapy in Chronic Kidney Disease: Days of Future Past

Anemia affects millions of patients with chronic kidney disease (CKD) and prompt iron supplementation can lead to reductions in the required dose of erythropoiesis-stimulating agents, thereby reducing medical costs. Oral and intravenous (IV) traditional iron preparations are considered far from ideal, primarily due to gastrointestinal intolerability and the potential risk of infusion reactions, respectively. Fortunately, the emergence of novel iron replacement therapies has engendered a paradigm shift in the treatment of iron deficiency anemia in patients with CKD. For example, oral ferric citrate is an efficacious and safe phosphate binder that increases iron stores to maintain hemoglobin levels. Additional benefits include reductions in fibroblast growth factor 23 levels and the activation of 1,25 dihydroxyvitamin D. The new-generation IV iron preparations ferumoxytol, iron isomaltoside 1000, and ferric carboxymaltose are characterized by a reduced risk of infusion reactions and are clinically well tolerated as a rapid high-dose infusion. In patients undergoing hemodialysis (HD), ferric pyrophosphate citrate (FPC) administered through dialysate enables the replacement of ongoing uremic and HD-related iron loss. FPC transports iron directly to transferrin, bypassing the reticuloendothelial system and avoiding iron sequestration. Moreover, this paper summarizes recent advancements of hypoxia-inducible factor prolyl hydroxylase inhibitors and future perspectives in renal anemia management.

The potential role of Na-K-ATPase and its signaling in the development of anemia in chronic kidney disease

Chronic kidney disease (CKD) is one of the most prominent diseases affecting our population today. According to the Factsheet published by Centers for Disease Control and Prevention (CDC), it effects approximately 15% of the total population in the United States in some way, shape, or form. Within the myriad of symptomatology associated with CKD, one of the most prevalent factors in terms of affecting quality of life is anemia. Anemia of CKD cannot be completely attributed to one mechanism or cause, but rather has a multifactorial origin in the pathophysiology of CKD. While briefly summarizing well-documented risk factors, this review, as a hypothesis, aims to explore the possible role of Na-K-ATPase and its signaling function [especially recent identified reactive oxygen species (ROS) amplification function] in the interwoven mechanisms of development of the anemia of CKD.

Diabetes mellitus in chronic kidney disease: Biomarkers beyond HbA1c to estimate glycemic control and diabetes-dependent morbidity and mortality

Diabetes mellitus (DM) is the leading cause of chronic kidney disease (CKD). Optimal glycemic control contributes to improved outcomes in patients with DM, particularly for microvascular damage, but blood glucose levels are too variable to provide an accurate assessment and instead markers averaging long-term glycemic load are used. The most established glycemic biomarker of long-term glycemic control is HbA1c. Nevertheless, HbA1c has pitfalls that limit its accuracy to estimate glycemic control, including the presence of altered red blood cell survival, hemoglobin glycation and suboptimal performance of HbA1c assays. Alternative methods to evaluate glycemic control in patients with DM include glycated albumin, fructosamine, 1-5 anhydroglucitol, continuous glucose measurement, self-monitoring of blood glucose and random blood glucose concentration measurements. Accordingly, our aim was to review the advantages and pitfalls of these methods in the context of CKD.

A role for tubular Na+/H+ exchanger NHE3 in the natriuretic effect of the SGLT2 inhibitor empagliflozin

Inhibitors of proximal tubular Na⁺-glucose cotransporter 2 (SGLT2) are natriuretic, and they lower blood pressure. There are reports that the activities of SGLT2 and Na⁺-H⁺ exchanger 3 (NHE3) are coordinated. If so, then part of the natriuretic response to an SGLT2 inhibitor is mediated by suppressing NHE3. To examine this further, we compared the effects of an SGLT2 inhibitor, empagliflozin, on urine composition and systolic blood pressure (SBP) in nondiabetic mice with tubule-specific NHE3 knockdown (NHE3-ko) and wild-type (WT) littermates. A single dose of empagliflozin, titrated to cause minimal glucosuria, increased urinary excretion of Na⁺ and bicarbonate and raised urine pH in WT mice but not in NHE3-ko mice. Chronic empagliflozin treatment tended to lower SBP despite higher renal renin mRNA expression and lowered the ratio of SBP to renin mRNA, indicating volume loss. This effect of empagliflozin depended on tubular NHE3. In diabetic Akita mice, chronic empagliflozin enhanced phosphorylation of NHE3 (S552/S605), changes previously linked to lesser NHE3-mediated reabsorption. Chronic empagliflozin also increased expression of genes involved with renal gluconeogenesis, bicarbonate regeneration, and ammonium formation. While this could reflect compensatory responses to acidification of proximal tubular cells resulting from reduced NHE3 activity, these effects were at least in part independent of tubular NHE3 and potentially indicated metabolic adaptations to urinary glucose loss. Moreover, empagliflozin increased luminal α-ketoglutarate, which may serve to stimulate compensatory distal NaCl reabsorption, while cogenerated and excreted ammonium balances urine losses of this "potential bicarbonate." The data implicate NHE3 as a determinant of the natriuretic effect of empagliflozin.

Complications of metabolic acidosis and alkalinizing therapy in chronic kidney disease patients: a clinician-directed organ-specific primer

Chronic kidney disease is prevalent, affecting more than one in ten adults. In this population, metabolic acidosis is considered a key underlying pathophysiological feature, tying together bone mineral disorders, sarcopenia, insulin resistance, vascular calcification, pro-inflammatory and pro-thrombotic states. This review aims to address the paucity of literature on alkalinizing agents, a promising treatment option that has known adverse effects.

Iron Deficiency in Chronic Kidney Disease: Updates on Pathophysiology, Diagnosis, and Treatment

Anemia is a complication that affects a majority of individuals with advanced CKD. Although relative deficiency of erythropoietin production is the major driver of anemia in CKD, iron deficiency stands out among the mechanisms contributing to the impaired erythropoiesis in the setting of reduced kidney function. Iron deficiency plays a significant role in anemia in CKD. This may be due to a true paucity of iron stores (absolute iron deficiency) or a relative (functional) deficiency which prevents the use of available iron stores. Several risk factors contribute to absolute and functional iron deficiency in CKD, including blood losses, impaired iron absorption, and chronic inflammation. The traditional biomarkers used for the diagnosis of iron-deficiency anemia (IDA) in patients with CKD have limitations, leading to persistent challenges in the detection and monitoring of IDA in these patients. Here, we review the pathophysiology and available diagnostic tests for IDA in CKD, we discuss the literature that has informed the current practice guidelines for the treatment of IDA in CKD, and we summarize the available oral and intravenous (IV) iron formulations for the treatment of IDA in CKD. Two important issues are addressed, including the potential risks of a more liberal approach to iron supplementation as well as the potential risks and benefits of IV versus oral iron supplementation in patients with CKD.

The Influence of Inflammation on Anemia in CKD Patients

Anemia is frequently observed in the course of chronic kidney disease (CKD) and it is associated with diminishing the quality of a patient’s life. It also enhances morbidity and mortality and hastens the CKD progression rate. Patients with CKD frequently suffer from a chronic inflammatory state which is related to a vast range of underlying factors. The results of studies have demonstrated that persistent inflammation may contribute to the variability in Hb levels and hyporesponsiveness to erythropoietin stimulating agents (ESA), which are frequently observed in CKD patients. The understanding of the impact of inflammatory cytokines on erythropoietin production and hepcidin synthesis will enable one to unravel the net of interactions of multiple factors involved in the pathogenesis of the anemia of chronic disease. It seems that anti-cytokine and anti-oxidative treatment strategies may be the future of pharmacological interventions aiming at the treatment of inflammation-associated hyporesponsiveness to ESA. The discovery of new therapeutic approaches towards the treatment of anemia in CKD patients has become highly awaited. The treatment of anemia with erythropoietin (EPO) was associated with great benefits for some patients but not all.

Treatment of Renal Anemia with Roxadustat: Advantages and Achievement

Background

Although renal anemia has attracted widespread attention, a large proportion of chronic kidney disease (CKD) patients with anemia still do not meet the hemoglobin (Hb) targets. The discovery of prolyl hydroxylase domain (PHD) enzymes as regulators of hypoxia-inducible factor (HIF)-dependent erythropoiesis has led to the development of novel therapeutic agents for renal anemia. Roxadustat, the first small-molecule HIF-PHD inhibitor, has completed the phase 3 trials. There are currently more than 15 phase 3 clinical trials worldwide assessing the efficacy and safety of roxadustat in CKD patients with anemia. This review will summarize recent findings of roxadustat in the treatment of renal anemia.

Summary

Although the administration of erythropoiesis-stimulating agents (ESAs) and iron supplementation are a well-established and highly effective therapeutic approach for renal anemia, there are several safety concerns. Current findings from phase 2 and 3 trials suggest that roxadustat is clinically effective and well tolerated. On the one hand, roxadustat could increase endogenous erythropoietin (EPO) levels within or near physiological range in a titratable manner by inducing HIF pathway activation transiently. On the other hand, roxadustat also improves iron metabolism by decreasing serum hepcidin and increasing intestinal iron absorption, which is beneficial to functional iron deficiency and absolute iron deficiency. More importantly, the erythropoietic response of roxadustat is independent of baseline inflammatory state of CKD patients. Thus, the discovery of roxadustat will revolutionize the treatment strategy for renal anemia.

Key Messages

Roxadustat is an emerging and promising therapeutic approach against anemia in CKD patients, which differs from those of conventional ESAs. Roxadustat corrects anemia of CKD patients through multiple pathways, beyond elevating EPO levels within physiological range, and also by handling iron metabolism (particularly decreasing the hepcidin levels). Furthermore, the Hb response of roxadustat is independent of the inflammatory microenvironment.

A journey from microenvironment to macroenvironment: the role of metaflammation and epigenetic changes in cardiorenal disease

Chronic non-communicable diseases have become a pandemic public problem in the 21st century, causing enormous burden on the economy, health and quality of life of societies. The role of a chronic inflammatory state in the pathogenesis of chronic disease has been more comprehensively recognized by recent findings. The new paradigm ‘metaflammation’ focuses on metabolism-induced (high fat or fructose-based diet or excessive calorie intake) chronic inflammation. There is a close correlation between the increased incidence of chronic kidney disease (CKD) and chronic heart failure with both increased inflammatory marker levels and western-type diet. In this review we describe the concept of metaflammation, its role in the development of CKD and chronic heart disease, the molecular and signalling pathways involved and the therapeutic consequences.

Effects of vadadustat on hemoglobin concentrations in patients receiving hemodialysis previously treated with erythropoiesis-stimulating agents

Background

Vadadustat, an inhibitor of hypoxia-inducible factor prolyl-4-hydroxylase domain dioxygenases, is an oral investigational agent in development for the treatment of anemia secondary to chronic kidney disease.

Methods

In this open-label Phase 2 trial, vadadustat was evaluated in 94 subjects receiving hemodialysis, previously maintained on epoetin alfa. Subjects were sequentially assigned to one of three vadadustat dose cohorts by starting dose: 300 mg once daily (QD), 450 mg QD or 450 mg thrice weekly (TIW). The primary endpoint was mean hemoglobin (Hb) change from pre-baseline average to midtrial (Weeks 7-8) and end-of-trial (Weeks 15-16) and was analyzed using available data (no imputation).

Results

Overall, 80, 73 and 68% of subjects in the 300 mg QD, 450 mg QD, and 450 mg TIW dose cohorts respectively, completed the study. For all dose cohorts no statistically significant mean change in Hb from pre-baseline average was observed, and mean Hb concentrations-analyzed using available data-remained stable at mid- and end-of-trial. There was one subject with an Hb excursion >13 g/dL. Overall, 83% of subjects experienced an adverse event (AE); the proportion of subjects who experienced at least one AE was similar among the three dose cohorts. The most frequently reported AEs were nausea (11.7%), diarrhea (10.6%) and vomiting (9.6%). No deaths occurred during the study. No serious AEs were attributed to vadadustat.

Conclusions

Vadadustat maintained mean Hb concentrations in subjects on hemodialysis previously receiving epoetin. These data support further investigation of vadadustat to assess its long-term safety and efficacy in subjects on hemodialysis.

Towards cardiovascular risks in children with chronic kidney disease: a prospective cohort study

Background: Children with chronic kidney disease (CKD) are at substantially high risk of morbidity and mortality from cardiovascular disease (CVD). Although this issue has been extensively studied in adults, little is known whether similar associations exist in the paediatric population. We therefore aimed to evaluate the cardiac structure and function in children with CKD, and investigate the factors that contribute to the development of CVD. Methods: A prospective cohort was established following 40 children with CKD treated in the nephrology unit at a high-volume, tertiary, teaching hospital and compared to age- and gender-matched controls of the same number.  We reviewed the patients’ medical records, assessed growth parameters, measured blood pressure, took blood samples, and performed echocardiography. Results: More than half of the CKD patients are hypertensive (N = 22; 55%) and were found to have a higher proportion of increased left ventricular mass index (LVMI) (75.5%; P = 0.001). In contrast, we did not find any significant association between CKD and both valvular calcification & left ventricular (LV) fractional shortening (FS) in children (P = 0.314). Furthermore, high LVMI is found to be correlated well with the following: anaemia, hypertension, CKD duration > one year, hyperparathyroidism, estimated glomerular filtration rate (eGFR) < 15ml/minute/1.73 m2 and death (P < 0.05). Conclusions: Despite the fact that LV systolic function is preserved and valvular calcification is usually absent, left ventricular hypertrophy (LVH) is common in children with CKD. Hypertension, anaemia, hyperparathyroidism, as well as the severity and duration of renal impairment, are amongst the additional risk factors that predispose to LVH. We contribute this study to the growing information of the review articles regarding the association between CKD and CVD in paediatrics.

Relationship of serum haemojuvelin and hepcidin levels with iron level and erythropoietin requirement in prevalent hepatitis C virus positive haemodialysis patients

AIM

Iron overload is frequently reported in haemodialysis (HD) patients particularly those with chronic hepatitis C virus (HCV) infection. Soluble haemojuvelin (sHJV) has recently emerged as one of the significant regulators of iron homeostasis and hepcidin expression. The aim of the present study was to evaluate the potential associations of sHJV and hepcidin with inflammation, iron parameters and erythropoietin requirement in prevalent HD patients with HCV.

METHODS

Serum sHJV and hepcidin were measured in 60 prevalent HD patients with [group I (n = 30)] and without [group II (n = 30)] HCV, and controls (n = 30) by enzyme-linked immunosorbent assay. Parameters related to anaemia, iron metabolism, inflammation, sHJV and hepcidin were measured.

RESULTS

Serum hepcidin in HCV positive versus negative groups was 89.40 ± 46.08 ng/mL and 224.1 ± 72.36 ng/mL, P = 0.000, respectively, while sHJV was 245 ± 1.338 ng/mL and 254 ± 0.762 ng/mL, P = 0.147, respectively in positive versus negative patients. In group I, hepcidin correlated with serum ferritin (r = -0.512 P = 0.005) and transferrin saturation (TSAT%) (r = 0.572, P = 0.000) and sHJV correlated with ferritin (r = 0.40, P 0.000), TSAT% (r = 0.450, P = 0.002) and a significant correlation also existed between sHJV and hepcidin (r = -0.259, P = 0.045). In the regression analysis, ferritin and TSAT% were able to predict sHJV; (standardized β = 0.52, P 0.001) and (standardized β = 0.48, P 0.010). Ferritin and sHJV were also able to predict hepcidin (standardized β = 0.627, P = 0.006) and (standardized β = 0.300, P = 0.007) in group I.

CONCLUSION

Soluble haemojuvelin levels seem to be associated with iron overload parameters and hepcidin levels in HCV positive HD patients.

The role of hypoxia-inducible factor stabilizers in the treatment of anemia in patients with chronic kidney disease

INTRODUCTION

The purpose of this study was to analyze the effects of hypoxia-inducible factor (HIF) stabilizers on anemia in non-dialysis-dependent (NDD) and dialysis-dependent (DD) chronic kidney disease (CKD) patients.

METHODS

Published studies were extracted from PubMed, China Biological Medicine Database (CBM), Wanfang database, and Cochrane Library on March 10, 2018, and relevant studies were pooled and included in a meta-analysis. Data on hemoglobin (Hb), ferritin, and hepcidin levels, total iron-binding capacity (TIBC), and incidence of adverse events (AEs) were extracted and pooled using Review Manager Version 5.3.

RESULTS

Data from nine selected studies were extracted. Meta-analysis of the included studies showed that HIF stabilizers reduced ferritin and hepcidin levels and increased Hb level and TIBC in NDD-CKD patients. However, HIF stabilizers only increased TIBC, and did not affect ferritin, hepcidin, and Hb levels in DD-CKD patients. Furthermore, no notable differences in AEs and severe AEs between NDD-CKD and DD-CKD patients were detected.

CONCLUSION

HIF stabilizers are effective for the treatment of anemia in NDD-CKD patients and safe for short-term use.

The smell of renal protection against chronic kidney disease: Hydrogen sulfide offers a potential stinky remedy

Chronic kidney disease (CKD) is a common global health challenge characterized by irreversible pathological processes that reduce kidney function and culminates in development of end-stage renal disease. It is associated with increased morbidity and mortality in addition to increased caregiver burden and higher financial cost. A central player in CKD pathogenesis and progression is renal hypoxia. Renal hypoxia stimulates induction of oxidative and endoplasmic reticulum stress, inflammation and tubulointerstitial fibrosis, which in turn, promote cellular susceptibility and further aggravate hypoxia, thus forming a pathological vicious cycle in CKD progression. Although the importance of CKD is widely appreciated, including improvements in the quality of existing therapies such as dialysis and transplantation, new therapeutic options are limited, as there is still increased morbidity, mortality and poor quality of life among CKD patients. Growing evidence indicates that hydrogen sulfide (H₂S), a small gaseous signaling molecule with an obnoxious smell, accumulates in the renal medulla under hypoxic conditions, and functions as an oxygen sensor that restores oxygen balance and increases medullary flow. Moreover, plasma H₂S level has been recently reported to be markedly reduced in CKD patients and animal models. Also, H₂S has been established to possess potent antioxidant, anti-inflammatory, and anti-fibrotic properties in several experimental models of kidney diseases, suggesting that its supplementation could protect against CKD and retard its progression. The purpose of this review is to discuss current clinical and experimental developments regarding CKD, its pathophysiology, and potential cellular and molecular mechanisms of protection by H₂S in experimental models of CKD.

The effects of probiotic supplement on hemoglobin in chronic renal failure patients under hemodialysis: A randomized clinical trial

Background:

Chronic inflammation is one of the causes of anemia in chronic renal failure patients under hemodialysis. Probiotics probably establish a balance between pro- and anti-inflammatory cytokines. The study was conducted to determine the effects of probiotic supplementation on hemoglobin (Hb) in hemodialysis patients.

Materials and Methods:

A parallel clinical trial was conducted in which patients were randomly allocated into two groups. The intervention group (n = 18) was given a 500 mg probiotic supplement (a capsule) every day whereas the control group (n = 18) received placebo (a capsule), both for 3 months. Hb levels and C-reactive protein (CRP) levels were measured for three periods. The data were analyzed in SPSS-16 using statistical tests including the t-test and repeated-measures ANOVA.

Results:

In the probiotic supplementation group, the mean Hb was 9.22 ± 1.04 mg/dl before the intervention and reached 10.85 ± 1.177 mg/dl afterward, while in the placebo group, the mean Hb level was 9.38 ± 0.97 mg/dl before the intervention and reached 10.03 ± 1.97 mg/dl afterward (P > 0.05). During the study, the placebo caused to increase of Hb temporary, but in longer term, the effect of probiotic was more manifested. Hb levels increased in both groups although the change was not statistically significant (P > 0.05). The findings showed no significant differences between the two groups in either the pre- or post-intervention CRP levels (P = 0.239).

Conclusion:

Probiotic supplementation decreased Hb fluctuations in hemodialysis patients but did not result in a significant increase in Hb levels. Similar studies are therefore recommended to be conducted with a prolonged duration of the study or an increased probiotic dose with larger sample size to complete the results of the present study.

Mean Corpuscular Volume and Mortality in Patients with CKD

BACKGROUND AND OBJECTIVES

Mean corpuscular volume is the measure of the average size of the circulatory erythrocyte, and it is principally used as an index for the differential diagnosis of anemia. Recently, mean corpuscular volume has been associated with mortality in many clinical settings. However, the association of mean corpuscular volume with mortality in patients with CKD has not been fully addressed.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a retrospective observational cohort study of 1439 patients with stages 3-5 CKD and baseline mean corpuscular volume values from 2004 to 2012 in a medical center. The study cohort was divided into the high-mean corpuscular volume group and the low-mean corpuscular volume group by the median value (90.8 fl) of mean corpuscular volume. The baseline patient information included demographic data, laboratory parameters, medications, and comorbid conditions. The independent association of mean corpuscular volume with mortality was examined using multivariate Cox regression analysis.

RESULTS

Of the 1439 participants, 234 patients (16.2%) died during a median follow-up of 1.9 years (interquartile range, 1.1-3.8 years). The crude overall mortality rate was significantly higher in the high-mean corpuscular volume group (high-mean corpuscular volume group, 22.7%; low-mean corpuscular volume group, 9.7%; P<0.001). In the fully adjusted models, the high-mean corpuscular volume group was associated with higher risks of all-cause mortality (hazard ratio, 2.19; 95% confidence interval, 1.62 to 2.96; P<0.001), cardiovascular mortality (hazard ratio, 3.57; 95% confidence interval, 1.80 to 7.06; P<0.001), and infection-related mortality (hazard ratio, 2.22; 95% confidence interval, 1.41 to 3.49; P=0.001) compared with the low-mean corpuscular volume group.

CONCLUSIONS

In patients with stages 3-5 CKD, mean corpuscular volume was associated with all-cause mortality, cardiovascular disease mortality, and infection-associated mortality, independent of other factors. The underlying pathophysiologic mechanisms warrant additional investigation.

[The role of renal anemia and cardiovascular disease in the progression of chronic glomerulonephritis]

AIM

To study the rate of chronic glomerulonephritis progression when added by anemia and cardiovascular disease (CVD).

SUBJECTS AND METHODS

231 patients (133 men and 98 women) with predialysis chronic glomerulonephritis (CGN) were examined. The patients' mean age of was 35.8±11.8 years; the disease duration was 1 to 17 years. The disease onset was the date when urinalysis showed evidence of persistent proteinuria and (or) hematuria. Besides, the time when anemia developed and the clinical and instrumental signs of CVD appeared was taken as the initial reference point; the time when end-stage renal failure was diagnosed was taken to be the endpoint. Red blood cell counts with the inclusion of its indices, hemoglobin concentration, hematocrit values, daily proteinuria values, and glomerular filtration rate were analyzed. The biochemical parameters included the concentrations of electrolytes, creatinine, fibrinogen, iron, cholesterol, total protein and C-reactive protein (CRP). Electrocardiography and echocardiography, bicycle ergometry and 24-hour ECG monitoring were used to detect CVD.

RESULTS

The presence of anemia and CVD in patients with predialysis CGN versus those without anemia and CVD was associated with an increase in the concentrations of CRP [36.2 and 12.6%; respectively; (p<0.05)], creatinine [123.0 (83.2-217.0) and 86.5 (72.0-128.5) µmol/L; (p<0.05)] and a decrease in GFR [65.4 (30.8-95.5) and 92.7 (64.5-122.3) ml/min; (p<0.05)]. The 8-year survival of patients with CGN concurrent with CVD was noted to be 58% whereas the renal survival in patients with CGN + CVD + anemia was shorter and the 6-year survival in this case was as high as 52%.

CONCLUSION

Anemia and CVD in patients with CGN serve as additional independent factors for the progression of the underlying disease. The concurrence of CGN, anemia, and CVD substantially reduces the predialysis period.

Thyroid function and cardiovascular events in chronic kidney disease patients

BACKGROUND AND AIMS

Abnormalities of thyroid function are commonly seen in chronic kidney disease (CKD) patients. They are associated with adverse clinical conditions such as atherosclerosis, endothelial dysfunction, inflammation and abnormal blood pressure variability. We investigated the association between thyroid disorders and endothelial function, assessed by flow-mediated dilatation (FMD) and carotid intima-media thickness (CIMT), and cardiovascular events (CVE) in CKD patients.

MATERIALS AND METHODS

This observational cohort study included 305 CKD (stages 1-5) patients. Routine biochemistry, including free T3, free T4 and thyroid stimulating hormone, fibroblast growth factor-23 (FGF-23) and FMD, CIMT were measured. We divided patients into four groups according to thyroid hormone status: euthyroidism, subclinical hyperthyroidism, subclinical hypothyroidism, and euthyroid sick syndrome. Fatal and composite CVE were recorded for a median 29 months.

RESULTS

Patients with subclinical hypothyroidism had a higher prevalence of hypertension and diabetes and also were more likely to have higher values of systolic CIMT, phosphorus, intact parathormone (iPTH), FGF-23, homeostasis model assessment-insulin resistance and lower levels of FMD than euthyroid patients. In the unadjusted survival analysis, subclinical hypothyroidism and euthyroid sick syndrome were associated with an increased risk for the outcome as compared with euthyroidism [hazard ratio 30.63 (95 % confidence interval 12.27-76.48) and 12.17 (3.70-39.98), respectively]. The effects of subclinical hypothyroidism and euthyroid sick syndrome were maintained even in fully adjusted models.

CONCLUSION

We demonstrated that subclinical hypothyroidism and euthyroid sick syndrome are associated with increased CVE in CKD patients. Further studies are needed to explore these issues.

Preoperative and Intraoperative Factors for Early Failure of Native Arteriovenous Fistulas

The aim of the study was to assess the potential predictive factors for early arteriovenous fistula (AVF) failure following the fistula first initiative. We retrospectively reviewed the data of 159 end-stage renal disease (ESRD) patients who underwent AVF creation. The preoperative factors such as demographic, comorbidity condition, laboratory parameters and medication, and intraoperative or surgical-related factors were assessed. In multivariate logistic regression analysis, significant predictive factors of early AVF failure were female gender (odds ratio (95% confidence interval): 2.63 (1.19-5.81); P = 0.017), higher body mass index (P = 0.038), and lower hemoglobin level (P = 0.048), while adjusting for preoperative factors or all factors. For adjusting of intraoperative factors, reduced venous diameter (P = 0.056) tended to be associated with early AVF failure. In conclusion, female gender, higher body mass index and lower hemoglobin level predicted the occurrence of early AVF failure in ESRD patients.

Kidney Dysfunction and Markers of Inflammation in the Multicenter AIDS Cohort Study

BACKGROUND

Human immunodeficiency virus (HIV)-infected individuals are at higher risk for chronic kidney disease than HIV-uninfected individuals. We investigated whether the inflammation present in treated HIV infection contributes to kidney dysfunction among HIV-infected men receiving highly active antiretroviral therapy.

METHODS

The glomerular filtration rate (GFR) was directly measured (using iohexol) along with 12 markers of inflammation in Multicenter AIDS Cohort Study participants. Exploratory factor analysis was used to identify inflammatory processes related to kidney dysfunction. The estimated levels of these inflammatory processes were used in adjusted logistic regression analyses evaluating cross-sectional associations with kidney function outcomes.

RESULTS

There were 434 HIV-infected men receiving highly active antiretroviral therapy and 200 HIV-uninfected men. HIV-infected men were younger (median age, 51 vs 53 years) and had higher urine protein-creatinine ratios (median, 98 vs 66 mg/g) but comparable GFRs (median, 109 vs 106 mL/min|1.73 m(2)). We found an inflammatory process dominated by markers: soluble tumor necrosis factor receptor 2, soluble interleukin 2 receptor α, soluble gp130, soluble CD27, and soluble CD14. An increase of 1 standard deviation in that inflammatory process was associated with significantly greater odds of GFR ≤90 mL/min/1.73 m(2) (odds ratio, 2.0) and urine protein >200 mg/g (odds ratio, 2.3).

CONCLUSIONS

Higher circulating levels of immune activation markers among treated HIV-infected men may partially explain their higher burden of kidney dysfunction compared with uninfected men.

Effect of erythropoietin on primed leucocyte expression profile

Resistance to erythropoietin (EPO) affects a significant number of anaemic patients with end-stage renal disease. Previous reports suggest that inflammation is one of the major independent predictors of EPO resistance, and the effects of EPO treatment on inflammatory mediators are not well established. The aim of this study was to investigate EPO-induced modification to gene expression in primary cultured leucocytes. Microarray experiments were performed on primed ex vivo peripheral blood mononuclear cells (PBMCs) and treated with human EPO-α. Data suggested that EPO-α modulated genes involved in cell movement and interaction in primed PBMCs. Of note, EPO-α exerts anti-inflammatory effects inhibiting the expression of pro-inflammatory cytokine IL-8 and its receptor CXCR2; by contrast, EPO-α increases expression of genes relating to promotion of inflammation encoding for IL-1β and CCL8, and induces de novo synthesis of IL-1α, CXCL1 and CXCL5 in primed cells. The reduction in MAPK p38-α activity is involved in modulating both IL-1β and IL-8 expression. Unlike the induction of MAPK, Erk1/2 activity leads to upregulation of IL-1β, but does not affect IL-8 expression and release. Furthermore, EPO-α treatment of primed cells induces the activation of caspase-1 upstream higher secretion of IL-1β, and this process is not dependent on caspase-8 activation. In conclusion, our findings highlight new potential molecules involved in EPO resistance and confirm the anti-inflammatory role for EPO, but also suggest a plausible in vivo scenario in which the positive correlation found between EPO resistance and elevated levels of some pro-inflammatory mediators is due to treatment with EPO itself.

Does erythropoietin cause hemoglobin variability--is it 'normal'?

Hemoglobin variability (Hb-var) in patients with chronic kidney disease has been stipulated to be a result of exogenous treatment with erythropoiesis stimulating agents (ESA) and has been related to mortality in dialysis patients. We hypothesized the existence of Hb-var independent of ESA administration and compared it to that in healthy adults using data from the Scripps-Kaiser and NHANES III databases. We studied the Hb-var in 1571 peritoneal dialysis patients which included 116 patients not requiring treatment with erythropoietin. We systematically studied the differences between the groups that needed ESA therapy and those who did not. White race and male sex were significant predictors of need for erythropoietin therapy. We found peritoneal dialysis patients to exhibit significantly increased Hb-var independent of treatment with exogenous erythropoietin (0.99 gm/dL vs. 1.17 gm/dL, p-value<0.001). We found age to be a significant determinant of Hb-var in the ESA treated group. Hb-var in younger patients (<30 years) was increased by 50% compared to young healthy adults. The Hb-var in elderly (>60 years) peritoneal dialysis patients was similar to that seen in healthy elders, suggesting similarity with anemia of aging. We conclude that exogenous ESA administration does not explain Hb-var entirely but may enhance it. Intrinsic factors affecting erythropoiesis including age may be the major determinants of Hb-var.

Interleukin-6 directly impairs the erythroid development of human TF-1 erythroleukemic cells

Anemia of inflammation or chronic disease is a highly prevalent form of anemia. The inflammatory cytokine interleukin-6 (IL-6) negatively correlates with hemoglobin concentration in many disease states. The IL-6-hepcidin antimicrobial peptide axis promotes iron-restricted anemia; however the full role of IL-6 in anemia of inflammation is not well-defined. We previously reported that chronic inflammation had a negative impact on maturation of erythroid progenitors in a mouse model. We hypothesized that IL-6 may be responsible for impaired erythropoiesis, independent of iron restriction. To test the hypothesis we utilized the human erythroleukemia TF-1 cell line to model erythroid maturation and exposed them to varying doses of IL-6 over six days. At 10 ng/ml, IL-6 significantly repressed erythropoietin-dependent TF-1 erythroid maturation. While IL-6 did not decrease the expression of genes associated with hemoglobin synthesis, we observed impaired hemoglobin synthesis as demonstrated by decreased benzidine staining. We also observed that IL-6 down regulated expression of the gene SLC4a1 which is expressed late in erythropoiesis. Those findings suggested that IL-6-dependent inhibition of hemoglobin synthesis might occur. We investigated the impact of IL-6 on mitochondria. IL-6 decreased the mitochondrial membrane potential at all treatment doses, and significantly decreased mitochondrial mass at the highest dose. Our studies indicate that IL-6 may impair mitochondrial function in maturing erythroid cells resulting in impaired hemoglobin production and erythroid maturation. Our findings may indicate a novel pathway of action for IL-6 in the anemia of inflammation, and draw attention to the potential for new therapeutic targets that affect late erythroid development.

Approaches to inverse-probability-of-treatment--weighted estimation with concurrent treatments

OBJECTIVES

In a setting with two concurrent treatments, inverse-probability-of-treatment weights can be used to estimate the joint treatment effects or the marginal effect of one treatment while taking the other to be a confounder. We explore these two approaches in a study of intravenous iron use in hemodialysis patients treated concurrently with epoetin alfa (EPO).

STUDY DESIGN AND SETTING

We linked US Renal Data System data with electronic health records (2004-2008) from a large dialysis provider. Using a retrospective cohort design with 776,203 records from 117,050 regular hemodialysis patients, we examined a composite outcome: mortality, myocardial infarction, or stroke.

RESULTS

With EPO as a joint treatment, inverse-probability-of-treatment weights were unstable, confidence intervals for treatment effects were wide, covariate balance was unsatisfactory, and the treatment and outcome models were sensitive to omission of the baseline EPO covariate. By handling EPO exposure as a confounder instead of a joint treatment, we derived stable weights and balanced treatment groups on measured covariates.

CONCLUSIONS

In settings with concurrent treatments, if only one treatment is of interest, then including the other in the treatment model as a confounder may result in more stable treatment effect estimates. Otherwise, extreme weights may necessitate additional analysis steps.

Carbamylation of serum albumin and erythropoietin resistance in end stage kidney disease

BACKGROUND AND OBJECTIVES

The mechanisms underlying erythropoietin resistance are not fully understood. Carbamylation is a post-translational protein modification that can alter the function of proteins, such as erythropoietin. The hypothesis of this study is that carbamylation burden is independently associated with erythropoietin resistance.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a nonconcurrent prospective cohort study of incident hemodialysis patients in the United States, carbamylated albumin, a surrogate of overall carbamylation burden, in 158 individuals at day 90 of dialysis initiation and erythropoietin resistance index (defined as average weekly erythropoietin dose [U] per kg body weight per hemoglobin [g/dl]) over the subsequent 90 days were measured. Linear regression was used to describe the relationship between carbamylated albumin and erythropoietin resistance index. Logistic regression characterized the relationship between erythropoietin resistance index, 1-year mortality, and carbamylation.

RESULTS

The median percent carbamylated albumin was 0.77% (interquartile range=0.58%-0.93%). Median erythropoietin resistance index was 18.7 units/kg per gram per deciliter (interquartile range=8.1-35.6 units/kg per gram per deciliter). Multivariable adjusted analysis showed that the highest quartile of carbamylated albumin was associated with a 72% higher erythropoietin resistance index compared with the lowest carbamylation quartile (P=0.01). Increasing erythropoietin resistance index was associated with a higher risk of death (odds ratio per unit increase in log-erythropoietin resistance index, 1.69; 95% confidence interval, 1.06 to 2.70). However, the association between erythropoietin resistance index and mortality was no longer statistically significant when carbamylation was included in the analysis (odds ratio, 1.44; 95% confidence interval, 0.87 to 2.37), with carbamylation showing the dominant association with death (odds ratio for high versus low carbamylation quartile, 4.53; 95% confidence interval, 1.20 to 17.10).

CONCLUSION

Carbamylation was associated with higher erythropoietin resistance index in incident dialysis patients and a better predictor of mortality than erythropoietin resistance index.

Anaemia management with C.E.R.A. in routine clinical practice: OCEANE (Cohorte Mircera patients non-dialyses), a national, multicenter, longitudinal, observational prospective study, in patients with chronic kidney disease not on dialysis

OBJECTIVE

The aim of this study was to describe the management of anaemia with a continuous erythropoietin receptor activator (C.E.R.A., methoxy polyethylene glycol epoetin-β), in patients with chronic kidney disease (CKD) not on dialysis, naïve or non-naïve to treatment with erythropoiesis-stimulating agents (ESAs) at inclusion.

DESIGN

National, multicentre, longitudinal, observational prospective study.

SETTING

133 nephrologists practicing in France selected patients during their routine follow-up visits. The study was non-interventional.

PARTICIPANTS

They were adult CKD patients not on dialysis or kidney transplant patients, naïve or not to ESA treatment: 524 patients not on dialysis (48% ESA-naïve) and 92 kidney transplant patients (24% ESA-naïve) were included and followed up every 3 months during 1 year.

OUTCOME MEASURES

The two main endpoints were the percentage of patients who achieved target haemoglobin (Hb) levels as per European Medicines Agency guidelines (10-12 g/dl) around 6 months of treatment and modalities of treatment.

RESULTS

Approximately one in two patients had an Hb level within 10-12 g/dl at baseline, and around 6 and 12 months of treatment. Ninety per cent of ESA-naïve patients achieved at least +1 g/dl increase over baseline Hb levels or had Hb within 10-12 g/dl around 6 and 12 months. The Hb level remained at approximately 11.5 g/dl during the 12 months of follow-up. Around 6 months: almost all patients were receiving a once-monthly subcutaneous dose of C.E.R.A. (patients not on dialysis: 95±54 µg; kidney transplant patients: 121±70 µg); approximately half the patients did not require a change in C.E.R.A. dose. Adverse effects related to C.E.R.A. were observed in less than 5% of patients and led to modification or discontinuation of treatment in 2%.

CONCLUSIONS

The efficacy and safety of C.E.R.A. in CKD patients not on dialysis, with or without kidney transplantation, were confirmed in routine clinical practice.