Treatment of anemia in heart failure: potential risks and benefits of intravenous iron therapy in cardiovascular disease

The mussel Mytilus galloprovincialis (Crimea, Black Sea) as a source of essential trace elements in human nutrition

Micronutrients, or essential trace elements, are important components in various metabolic processes inherent to the normal functioning of organism. To date, a substantial part of the world population suffers from a lack of micronutrients in the diet. Mussels are an important and cheap source of nutrients, which can be utilized to mitigate the micronutrient deficiency in the world. In the present work, using inductively coupled plasma mass spectrometry, the contents of the micronutrients Cr, Fe, Cu, Zn, Se, I, and Mo were studied for the first time in soft tissues, shell liquor, and byssus of females and males of the mussel Mytilus galloprovincialis as the promising sources of essential elements in the human diet. Fe, Zn, and I were the most abundant micronutrients in the three body parts. Significant sex-related differences in the body parts were detected only for Fe, which was more abundant in byssus of males, and Zn, which exhibited higher levels in shell liquor of females. Significant tissue-related differences were registered in the contents of all the elements under study. M. galloprovincialis meat was characterized as the optimal source of I and Se for covering the daily human needs. Regardless of sex, byssus turned out to be richer in Fe, I, Cu, Cr, and Mo in comparison with soft tissues, which fact allows recommending this body part for the preparation of dietary supplements to compensate for the deficiency of these micronutrients in the human body.

Investigating binding mechanism of thymoquinone to human transferrin, targeting Alzheimer's disease therapy

Iron deposition in the central nervous system (CNS) is one of the causes of neurodegenerative diseases. Human transferrin (hTf) acts as an iron carrier present in the blood plasma, preventing it from contributing to redox reactions. Plant compounds and their derivatives are frequently being used in preventing or delaying Alzheimer's disease (AD). Thymoquinone (TQ), a natural product has gained popularity because of its broad therapeutic applications. TQ is one of the significant phytoconstituent of Nigella sativa. The binding of TQ to hTf was determined by spectroscopic methods and isothermal titration calorimetry. We have observed that TQ strongly binds to hTf with a binding constant (K) of 0.22 × 10⁶ M^-1 and forming a stable complex. In addition, isothermal titration calorimetry revealed the spontaneous binding of TQ with hTf. Molecular docking analysis showed key residues of the hTf that were involved in the binding to TQ. We further performed a 250 ns molecular dynamics simulation which deciphered the dynamics and stability of the hTf-TQ complex. Structure analysis suggested that the binding of TQ doesn't cause any significant alterations in the hTf structure during the course of simulation and a stable complex is formed. Altogether, we have elucidated the mechanism of binding of TQ with hTf, which can be further implicated in the development of a novel strategy for AD therapy.

Why is Iron Deficiency Recognised as an Important Comorbidity in Heart Failure?

There is an increasing awareness of the prevalence of iron deficiency in patients with heart failure (HF), and its contributory role in the morbidity and mortality of HF. Iron is a trace element necessary for cells due to its capacity to transport oxygen and electrons. The prevalence of iron deficiency increases with the severity of HF. For a long time the influence of iron deficiency was underestimated, especially in terms of worsening of cardiovascular diseases and developing anaemia. In recent years, studies with intravenous iron agents in patients with iron deficiency and HF showed new insights into the improvement of iron therapy. Additionally, experimental studies supporting the understanding of iron metabolism and the resulting pathophysiological pathways of iron have been carried out. The aim of this mini review is to highlight why iron deficiency is recognised as an important comorbidity in HF.

Left ventricular ejection fraction as therapeutic target: is it the ideal marker?

Heart failure (HF) consists the fastest growing clinical cardiac disease. HF patients are categorized on the basis of underlying left ventricular ejection fraction (LVEF) into HF with preserved EF (HFpEF), reduced LVEF (HFrEF), and mid-range LVEF (HFmrEF). While LVEF is the most commonly used surrogate marker of left ventricular (LV) systolic function, the implementation of two-dimensional echocardiography in estimating this parameter imposes certain caveats on current HF classification. Most importantly, LVEF could fluctuate in repeated measurements or even recover after treatment, thus blunting the borders between proposed categories of HF and enabling upward classification of patients. Under this prism, we sought to summarize possible procedures to improve systolic function in patients with HFrEF either naturally or by the means of pharmacologic and non-pharmacologic treatment and devices. Therefore, we reviewed established pharmacotherapy, including beta-blockers, inhibitors of renin-angiotensin-aldosterone axis, statins, and digoxin as well as novel treatments like sacubitril-valsartan, ranolazine, and ivabradine. In addition, we assessed evidence in favor of cardiac resynchronization therapy and exercise training programs. Finally, innovative therapeutic strategies, including stem cells, xanthine oxidase inhibitors, antibiotic regimens, and omega-3 polyunsaturated fatty acids, were also taken into consideration. We concluded that LVEF is subject to changes in HF after intervention and besides the aforementioned HFrEF, HFpEF, and HFmrEF categories, a new entity of HF patients with recovered LVEF should be acknowledged. An improved global and refined LV function assessment by sophisticated imaging modalities and circulating biomarkers is expected to render HF classification more accurate and indicate patients with viable-yet dysfunctional-myocardium and favorable characteristics as the ideal candidates for LVEF recovery by individualized HF therapy.

Iron deficiency in heart failure: a practical guide

Iron is an element necessary for cells due to its capacity of transporting oxygen and electrons. One of the important co-morbidities in heart failure is iron deficiency. Iron has relevant biological functions, for example, the formation of haemoglobin, myoglobin and numerous enzymatic groups. The prevalence of iron deficiency increases with the severity of heart failure. For a long time, the influence of iron deficiency was underestimated especially in terms of worsening of cardiovascular diseases and of developing anaemia. In recent years, studies with intravenous iron agents in patients with iron deficiency and cardiovascular diseases indicated new insights in the improvement of therapy. Experimental studies support the understanding of iron metabolism. Many physicians remain doubtful of the use of intravenous iron due to reports of side effects. The aim of this review is to describe iron metabolism in humans, to highlight the influence of iron deficiency on the course and symptoms of heart failure, discuss diagnostic tools of iron deficiency and provide guidance on the use of intravenous iron.

Anemia, heart failure and evidence-based clinical management

Anemia is a prevalent comorbidity and marker of a poorer prognosis in patients with heart failure (HF). Its clinical relevance, as well as its pathophysiology and the clinical management of these patients are important subjects in the specialized literature. In the present review, we describe the current concepts on the pathophysiology of anemia in HF, its diagnostic criteria, and the recommendations for iron supplementation. Also, we make a critical analysis of the major studies showing evidences on the benefits of this supplementation. The four main components of anemia are addressed: chronic disease, dilutional, "renal" and malabsorption. In patients with HF, the diagnostic criteria are the same as those used in the general population: serum ferritin levels lower than 30 mcg/L in patients without kidney diseases and lower than 100 mcg/L or serum ferritin levels between 100-299 mcg/L with transferring saturation lower than 20% in patients with chronic kidney diseases. Finally, the therapeutic possibilities for anemia in this specific patient population are discussed.

Cardioprotection by Hepc1 in cTnT(R141W) transgenic mice

Hepcidin 1 (Hepc1) is a peptide hormone secreted by the liver in response to iron loading. It is expressed in the heart and is thought to play a role in the regulation of iron homeostasis in an autocrine and paracrine fashion. We have shown that expression of Hepc1 is strongly down-regulated in the heart of the cTnT(R141W) transgenic mouse model of dilated cardiomyopathy (DCM) at 3 months of age. Transgenic mice with heart tissue-specific Hepc1 expression alone or in combination with the cTnT(R141W) mutation were produced to study the effects of Hepc1 on DCM. Transgenic expression of Hepc1 was found to be nonlethal and resulted in decreased mortality in cTnT(R141W) transgenic mice, from 29.6 to 7.4%(n  = 27; P < 0.05), through 7 months of age. Expression of Hepc1 also brought about increases in the left ventricular wall, as well as ejection fraction and fractional shortening. In addition, the expression of Hepc1 inhibited the fibrosis and ultra-structural alterations seen in cTnT(R141W) transgenic mice. Furthermore, transgenic expression of Hepc1 restored the iron level and phosphorylation level of extracellular signal-regulated kinases 1/2 (ERK1/2) in the heart tissues of cTnT(R141W) transgenic mice. It was concluded that transgenic expression of Hepc1 compensated for the loss of Hepc1 expression and the release of iron and brought about a marked improvement in the pathologic phenotype of DCM, in which the ERK1/2 signal pathway might play an important role.

Iron deficiency in community-dwelling US adults with self-reported heart failure in the National Health and Nutrition Examination Survey III: prevalence and associations with anemia and inflammation

BACKGROUND

Iron deficiency has been proposed as a potential therapeutic target in heart failure, but its prevalence and association with anemia and clinical outcomes in community-dwelling adults with heart failure have not been well characterized.

METHODS AND RESULTS

Using data from the Third National Health and Nutrition Examination Survey, we evaluated the associations between iron deficiency, hemoglobin, C-reactive protein (CRP), and all-cause and cardiovascular mortality in 574 adults with self-reported heart failure. Iron deficiency was defined in both absolute and functional terms as a ferritin level <100 μg/L or between 100 and 299 μg/L if the transferrin saturation was <20%. Iron deficiency was present in 61.3% of participants and was associated with reduced mean hemoglobin (13.6 versus 14.2 g/dL, P=0.007) and increased mean CRP (0.95 versus 0.63 mg/dL, P=0.04). Over a median of 6.7 years of follow-up, there were 300 all-cause deaths, 193 of which were from cardiovascular causes. In age- and sex-adjusted Cox proportional hazards models, hemoglobin, CRP, and transferrin saturation but not iron deficiency were significantly associated with all-cause and cardiovascular mortality. In multivariate models, hemoglobin remained an independent predictor of cardiovascular mortality, whereas CRP remained an independent predictor of both all-cause and cardiovascular mortality.

CONCLUSIONS

Iron deficiency is common in heart failure and is associated with decreased hemoglobin and increased CRP. In multivariate analysis, hemoglobin was associated with cardiovascular mortality while CRP was associated with both all-cause and cardiovascular mortality. Iron deficiency was not associated with all-cause or cardiovascular mortality in this cohort.

Cardiorenal syndromes

Cardiorenal syndromes (CRS) have been subclassified as five defined entities which represent clinical circumstances in which both the heart and the kidney are involved in a bidirectional injury and dysfunction via a final common pathway of cell-to-cell death and accelerated apoptosis mediated by oxidative stress. Types 1 and 2 involve acute and chronic cardiovascular disease (CVD) scenarios leading to acute kidney injury or accelerated chronic kidney disease. Types 2 and 3 describe acute and chronic kidney disease leading primarily to heart failure, although it is possible that acute coronary syndromes, stroke, and arrhythmias could be CVD outcomes in these forms of CRS. Finally, CRS type 5 describes a simultaneous insult to both heart and kidneys, such as sepsis, where both organs are injured simultaneously. Both blood and urine biomarkers are reviewed in this paper and offer a considerable opportunity to enhance the understanding of the pathophysiology and known epidemiology of these recently defined syndromes.