The influence of Erythropoietin on platelet activation, thrombin generation and FVII/active FVII in patients with AMI

Cardiovascular safety of current and emerging drugs to treat anaemia in chronic kidney disease: a safety review

INTRODUCTION

Erythropoiesis-stimulating agents (ESAs) are the standard of treatment for anemia in chronic kidney disease. Hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHI) are small molecules that stimulate endogenous erythropoietin synthesis.

AREAS COVERED

The cardiovascular safety of ESAs and HIF-PHIs. We performed a PubMed search using several key words, including anemia, chronic kidney disease, safety, erythropoiesis stimulating agents, HIF-PH inhibitors.

EXPERT OPINION

ESAs are well-tolerated drugs with a long history of use; there are safety concerns, especially when targeting high hemoglobin levels. HIF-PHIs have comparable efficacy to ESAs in correcting anemia. Contrary to expectations, randomized phase 3 clinical trials have shown that overall HIF-PHIs were non-inferior to ESA or placebo with respect to the risk of cardiovascular endpoints. In addition, some phase 3 trials raised potential safety concerns regarding cardiovascular and thrombotic events, particularly in non-dialysis patients.Today, HIF-PHIs represent an additional treatment option for anemia in patients with chronic kidney disease. This has made the management of anemia in CKD more complex and heterogeneous. A better understanding of the mechanisms causing hypo-responsiveness to ESAs, combined with an individualized approach that balances ESAs, HIF-PHIs and iron doses, could increase the benefits while reducing the risks.

Are There Any Cardioprotective Effects or Safety Concerns of Erythropoietin in Patients With Myocardial Infarction? A Systematic Review

Myocardial infarction (MI) is a global cause of morbidity and mortality. MI is the outcome of a chronic process termed atherosclerosis, a buildup of fatty and other substances called plaques inside the coronary vessels, causing hardening and thickening of the arterial wall. Erythropoietin (EPO) is a pleiotropic cytokine released mainly by the kidneys in adults. Besides its well-known erythropoietic functions, EPO possesses anti-apoptotic, mitogenic, and angiogenic effects. This review aims to analyze the strength of any therapeutic or protective value of EPO on the heart and safety concerns regarding its administration in MI individuals.

This systematic review was performed based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Four databases (PubMed, PubMed Central, Google Scholar, and Sciences Direct) were employed to search for articles published in the last 10 years. Focused studies were relevant articles in the English language, trials, reviews, meta-analyses, and studies with a control group. Following the quality assessment process, nine studies were eligible and hence were included in the review consisting of six randomized controlled trials and three systematic reviews and meta-analyses. Contrary to preclinical studies, EPO administration did not significantly have notable effects on mortality, major adverse cardiovascular events, or infarction size reduction. Significant left ventricle ejection fraction amelioration was not appreciated either. However, EPO seems to reduce the incidence of post-MI arrhythmias.

Cyclic thrombocytopenia related to erythropoietin-dependent anti-platelet anti-GPIV/IIIb antibody in hemodialysis

We describe herein the case of a 65-year-old patient on chronic hemodialysis with a medical history of idiopathic thrombocytopenia who experienced numerous episodes of severe thrombocytopenia with no specific diagnosis. Further analysis of the evolution of the platelet count showed that cyclic thrombocytopenia occurred after each injection of recombinant erythropoietin (rHu-EPO). Exploration of the involved mechanisms revealed the presence of a rHu-EPO-dependent anti-GPIV/IIIb antibody associated with a significant increase in GPIV/IIIb expression on her platelets after the addition of rHu-EPO. EPO was discontinued and the patient was treated with roxadustat with favorable results on her hemoglobin and platelet counts.

Management of Perioperative Iron Deficiency in Cardiac Surgery: A Modified RAND Delphi Study

BACKGROUND

Over the last decade, preoperative anemia has become recognized as a clinical condition in need of management. Although the etiology of preoperative anemia can be multifactorial, two-thirds of anemic elective surgical patients have iron deficiency anemia. At the same time, one-third of non-anemic elective surgical patients are also iron deficient.

METHODS

Modified-RAND Delphi methodology was employed to identify areas of consensus among an expert panel regarding the management of iron deficiency in patients undergoing cardiac surgery. A list of statements was sent to panel members to respond to using a five-point Likert Scale. All panel members subsequently attended a face-to-face meeting. The initial survey was presented and discussed, and panel members responded to each statement on the Likert scale again. Based on the second survey, the panel came to a consensus on recommendations.

RESULTS

The panel recommended all patients undergoing cardiac surgery be evaluated for iron deficiency, whether or not anemia is present. Evaluation should include iron studies and reticulocyte hemoglobin content. If iron deficiency is present, with or without anemia, patients should receive parenteral iron. Erythropoietin stimulating agents may be appropriate for some patients.

CONCLUSIONS

Consensus of an expert panel resulted in a standardized approach to diagnosing and managing iron deficiency in patients undergoing cardiac surgery.

Erythropoietin therapy after out-of-hospital cardiac arrest: A systematic review and meta-analysis

AIM

To assess safety and efficacy of early erythropoietin (Epo) administration in patients with out-of-hospital cardiac arrest (OHCA).

METHODS

A systematic literature search was performed using PubMed, MEDLINE, EMBASE, EBSCO, CINAHL, Web of Science and Cochrane databases, of all studies published from the inception through October 10, 2016. Inclusion criteria included: (1) Adult humans with OHCA and successful sustained return of spontaneous circulation; and (2) studies including mortality/brain death, acute thrombotic events as their end points. Primary efficacy outcome was “brain death or Cerebral Performance Category (CPC) score of 5”. Secondary outcomes were “CPC score 1, and 2-4”, “overall thrombotic events” and “acute coronary stent thrombosis”.

RESULTS

We analyzed a total of 606 participants (n = 276 received Epo and n = 330 with standard of care alone) who experienced OHCA enrolled in 3 clinical trials. No significant difference was observed between the Epo and no Epo group in brain death or CPC score 5 (OR = 0.77; 95%CI: 0.42-1.39), CPC score 1 (OR = 1.16, 95%CI: 0.82-1.64), and CPC score 2-4 (OR = 0.77, 95%CI: 0.44-1.36). Epo group was associated with increased thrombotic complications (OR = 2.41, 95%CI: 1.26-4.62) and acute coronary stent thrombosis (OR = 8.16, 95%CI: 1.39-47.99). No publication bias was observed.

CONCLUSION

Our study demonstrates no improvement in neurological outcomes and increased incidence of thrombotic events and acute coronary stent thrombosis in OHCA patients who were treated with Epo in addition to standard therapy.

Immune Activation of Platelets in Response to Serial Phlebotomy in Pigtailed Macaques (Macaca nemestrina)

Serial phlebotomy is a common sampling practice for repeated-measures studies in biomedical research. In NHP, the effect of serial blood collection on RBC parameters has been characterized, but the effects on platelet parameters and other aspects of the hemogram have not been well studied. We sought to characterize the circulating platelet phenotype throughout the course of 7 serial phlebotomies spanning 30 d in pigtailed macaques (Macaca nemestrina). Phlebotomy was performed on 23 animals at days 0, 2, 4, 7, 10, 21, and 30 to quantify the circulating platelet count and markers of both hemostatic and immune platelet activation. Platelet immune activation was characterized by increases in surface MHC class I and II expression and increases in circulating platelet-leukocyte aggregates. These changes occurred in the absence of increases in the prohemostatic markers P-selectin and CD40L and without evidence of adverse clinical effects. Mild increases in platelet count, mean platelet volume, and immune activation occurred early in the study. After day 21, mean platelet volume and other hematologic parameters returned to baseline while changes in platelet count and immune activation were greater than during the first 10 d of the study. These data demonstrate that serial phlebotomy in NHP has delayed effects on platelet parameters, which may be a source of clinically silent, immunologic and physiologic variability within repeated measures studies. The impact of these effects on research aims should be considered when designing protocols requiring serial phlebotomy in NHP.

Red Blood Cell Function and Dysfunction: Redox Regulation, Nitric Oxide Metabolism, Anemia

SIGNIFICANCE

Recent clinical evidence identified anemia to be correlated with severe complications of cardiovascular disease (CVD) such as bleeding, thromboembolic events, stroke, hypertension, arrhythmias, and inflammation, particularly in elderly patients. The underlying mechanisms of these complications are largely unidentified. Recent Advances: Previously, red blood cells (RBCs) were considered exclusively as transporters of oxygen and nutrients to the tissues. More recent experimental evidence indicates that RBCs are important interorgan communication systems with additional functions, including participation in control of systemic nitric oxide metabolism, redox regulation, blood rheology, and viscosity. In this article, we aim to revise and discuss the potential impact of these noncanonical functions of RBCs and their dysfunction in the cardiovascular system and in anemia.

CRITICAL ISSUES

The mechanistic links between changes of RBC functional properties and cardiovascular complications related to anemia have not been untangled so far.

FUTURE DIRECTIONS

To allow a better understanding of the complications associated with anemia in CVD, basic and translational science studies should be focused on identifying the role of noncanonical functions of RBCs in the cardiovascular system and on defining intrinsic and/or systemic dysfunction of RBCs in anemia and its relationship to CVD both in animal models and clinical settings. Antioxid. Redox Signal. 26, 718-742.

Low-dose erythropoietin treatment is not associated with clinical benefits in severely anaemic Jehovah's Witnesses: a plea for a change

BACKGROUND

Jehovah's Witnesses who refuse blood transfusion have high mortality. Erythropoietin (EPO) has been used as an alternative to blood transfusion. The optimal dosing of EPO in anaemic Jehovah's Witnesses is unknown. The aim of our study was to evaluate the clinical benefits of treatment with a low dose (<600 IU/kg/week) of epoietin beta (EPO-β).

MATERIALS AND METHODS

This was an observational study, retrospectively considering a 10-year period during which 3,529 adult Jehovah's Witnesses with a total of 10,786 hospital admissions were identified from databases of four major public hospitals in New Zealand. Patients with severe symptomatic anaemia (haemoglobin <80 g/L) who were unable to tolerate physical activity were included in the study. Patients treated without EPO were assigned to the conventional therapy group and those treated with EPO to the EPO treatment group.

RESULTS

Ninety-one Jehovah's Witnesses met the eligibility criteria. Propensity score matching yielded a total of 57 patients. Patients treated with conventional therapy and those treated with EPO had similar durations of severe anaemia (average difference 6.25 days, 95% confidence interval [CI]: -3.77-16.27 days; p=0.221). The mortality rate among Jehovah's Witnesses treated with conventional therapy was 4.68 per year (95% CI: 2.23-9.82), while that in those treated with EPO was 2.77 per year (95% CI: 0.89-8.60). Treatment with EPO was associated with a mortality ratio of 0.59 (95% CI: 0.1-2.6; p=0.236). Both groups of patients had similar in-hospital survival (p=0.703).

DISCUSSION

Treatment with low-dose EPO-β was not associated with either shorter duration of severe anaemia or a reduction in mortality.

Embolic Stroke due to a Common Carotid Artery Thrombus in a Young Patient with Severe Iron-Deficiency Anemia without Thrombocytosis

This case report describes a 41-year-old previously healthy male who presented with stuttering transient ischemic symptoms and radiographic evidence of a left common carotid artery thrombus as well as acute and subacute ischemic infarcts in the left middle cerebral artery territory. An exhaustive stroke work-up did not provide a plausible etiology for his symptoms. His complete blood count and iron studies, however, revealed evidence of severe iron-deficiency anemia without reactive thrombocytosis. His stool guaiac test was positive. He was discharged home on oral antithrombotic agents and aggressive iron replacement therapy with a plan for repeat vascular imaging in 3 months and a colonoscopy. This case report suggests that severe iron-deficiency anemia with or without reactive thrombocytosis should be viewed as a possible hematologic condition associated with thrombotic tendencies and a risk factor for ischemic stroke, especially in young adults. Aggressive iron supplementation and short-term antithrombotic therapy with follow-up vascular imaging are a reasonable treatment for these patients.