Cardiovascular Manifestations of Hemochromatosis: A Review of Pathophysiology, Mechanisms, and Treatment Options

Thalassemia and iron overload cardiomyopathy: Pathophysiological insights, clinical implications, and management strategies

Thalassemia is a hereditary blood disorder characterized by reduced hemoglobin production, leading to chronic anemia. A major complication of thalassemia is iron overload, primarily due to regular blood transfusions and increased gastrointestinal iron absorption, which can lead to iron overload cardiomyopathy, a significant cause of morbidity and mortality in thalassemia patients. This review aims to provide an in-depth analysis of the pathophysiological mechanisms underlying iron overload cardiomyopathy in thalassemia, examining how excessive iron accumulation disrupts cardiac function through oxidative stress, cellular damage, and altered calcium homeostasis. Clinical manifestations, including fatigue, arrhythmias, and heart failure, are discussed alongside diagnostic strategies such as echocardiography and cardiac MRI for early detection and monitoring. Management approaches focusing on iron chelation therapy, lifestyle modifications, and advanced interventions like gene therapy are explored. The review also highlights the importance of early diagnosis, regular monitoring, and patient adherence to therapy to prevent the progression of cardiomyopathy. Recent advances in treatment and future research directions, including personalized medicine, and gene editing technologies, are presented. Addressing the challenges in managing iron overload in thalassemia patients is crucial for improving outcomes and enhancing quality of life.

Cardiotoxicity of Iron and Zinc and Their Association with the Mitochondrial Unfolded Protein Response in Humans

This study was designed to examine the association between myocardial concentrations of the trace elements Cu, Fe, Mn, Mo, and Zn and the expression of mitochondrial unfolded protein response (UPRmt) elements and the age of patients who received heart transplantation or a left-ventricular assist device (ageHTx/LVAD). Inductively coupled plasma mass spectrometry was used to determine the concentration of Cu, Fe, Mn, Mo, and Zn in the myocardium of control subjects and patients undergoing heart transplantation or left-ventricular assist device (LVAD) implantation. We used ELISA to quantify the expression of UPRmt proteins and 4-Hydroxynonenal (4-HNE), which served as a marker of oxidative-stress-induced lipid peroxidation. Concentrations of Cu, Mn, Mo, and Zn were similar in the control and heart failure (HF) myocardium, while Fe showed a significant decrease in the HF group compared to the control. A higher cumulative concentration of Fe and Zn in the myocardium was associated with reduced ageHTx/LVAD, which was not observed for other combinations of trace elements or their individual effects. The trace elements Cu, Mn, and Zn showed positive correlations with several UPRmt proteins, while Fe had a negative correlation with UPRmt effector protease YME1L. None of the trace elements correlated with 4-HNE in the myocardium. The concentrations of the trace elements Mn and Zn were significantly higher in the myocardium of patients with dilated cardiomyopathy than in patients with ischemic cardiomyopathy. A higher cumulative concentration of Fe and Zn in the myocardium was associated with a younger age at which patients received heart transplantation or LVAD, potentially suggesting an acceleration of HF. A positive correlation between myocardial Cu, Mn, and Zn and the expression of UPRmt proteins and a negative correlation between myocardial Fe and YME1L expression suggest that these trace elements exerted their actions on the human heart by interacting with the UPRmt. An altered generation of oxidative stress was not an underlying mechanism of the observed changes.

Maternal hemoglobin and iron status in early pregnancy and childhood cardiac outcomes

BACKGROUND & AIMS

Dysregulation of iron homeostasis is associated with cardiac alterations in a sex-dependent manner in adults. It is unknown whether iron status during pregnancy has long-term impact on cardiovascular health, and if this association is influenced by sex. Therefore, this study aimed to evaluate sex-specific association between maternal iron status during early pregnancy and cardiac outcomes in children aged 10 years.

METHODS

In a population-based cohort study among 1972 mother-child pairs, hemoglobin and ferritin were measured in early pregnancy (<18 weeks) and categorized into anemia (hemoglobin<11 g/dL), elevated hemoglobin (hemoglobin≥13.2 g/dL), iron deficiency (ferritin<15 μg/L), and iron overload (ferritin>150 μg/L). At 10 years of age, cardiac MRI was performed to measure right and left cardiac outcomes of function (ventricular end-diastolic volume (RVEDV and LVEDV) and ejection fraction (RVEF and LVEF)), and structure (left ventricular mass (LVM), and left ventricular mass-to-volume ratio (LMVR)). Results are presented for boys and girls separately and models were adjusted for confounders and multiple testing.

RESULTS

In boys, one standard deviation score (SDS) increase in maternal hemoglobin was associated with lower RVEDV and LVEDV (difference (95%CI) -0.10 (-0.17, -0.03) SDS and -0.09 (-0.16, -0.03) SDS, respectively). In boys, maternal anemia, as compared to normal hemoglobin levels, was associated with higher LVEDV (difference 0.34 (0.10, 0.59) SDS). No associations were observed for other cardiac outcomes and for ferritin in boys. No associations were observed in girls.

CONCLUSION

In boys, dysregulated iron status during early pregnancy might permanently alter cardiovascular RVEDV and LVEDV function. Underlying mechanisms need further study.

Elevated plasma hepcidin concentrations are associated with an increased risk of mortality and nonfatal cardiovascular events in patients with type 2 diabetes: a prospective study

BACKGROUND

The effect of plasma hepcidin concentrations on the long-term risk of developing adverse cardiovascular outcomes in people with type 2 diabetes mellitus (T2DM) is unclear.

METHODS

We followed for a median of 55.6 months 213 outpatients with established T2DM (45.5% women, mean age 69 ± 10 years; BMI 28.7 ± 4.7 kg/m2; median diabetes duration 11 years). Baseline plasma ferritin and hepcidin concentrations were measured with an electrochemiluminescence immunoassay and mass spectrometry-based assay, respectively. The primary study outcome was a composite of all-cause mortality or incident nonfatal cardiovascular events (inclusive of myocardial infarction, permanent atrial fibrillation, ischemic stroke, or new hospitalization for heart failure).

RESULTS

42 patients developed the primary composite outcome over a median follow-up of 55.6 months. After stratifying patients by baseline hepcidin tertiles [1st tertile: median hepcidin 1.04 (IQR 0.50-1.95) nmol/L, 2nd tertile: 3.81 (IQR 3.01-4-42) nmol/L and 3rd tertile: 7.72 (IQR 6.37-10.4) nmol/L], the risk of developing the primary composite outcome in patients in the 3rd tertile was double that of patients in the 1st and 2nd tertile combined (unadjusted hazard ratio [HR] 2.32, 95%CI 1.27-4.26; p = 0.007). This risk was not attenuated after adjustment for age, sex, adiposity measures, smoking, hypertension, statin use, antiplatelet medication use, plasma hs-C-reactive protein and ferritin concentrations (adjusted HR 2.53, 95%CI 1.27-5.03; p = 0.008).

CONCLUSIONS

In outpatients with T2DM, higher baseline hepcidin concentrations were strongly associated with an increased long-term risk of overall mortality or nonfatal cardiovascular events, even after adjustment for established cardiovascular risk factors, plasma ferritin concentrations, medication use, and other potential confounders.

Redox homeostasis in cardiac fibrosis: Focus on metal ion metabolism

Cardiac fibrosis is a major public health problem worldwide, with high morbidity and mortality, affecting almost all patients with heart disease worldwide. It is characterized by fibroblast activation, abnormal proliferation, excessive deposition, and abnormal distribution of extracellular matrix (ECM) proteins. The maladaptive process of cardiac fibrosis is complex and often involves multiple mechanisms. With the increasing research on cardiac fibrosis, redox has been recognized as an important part of cardiac remodeling, and an imbalance in redox homeostasis can adversely affect the function and structure of the heart. The metabolism of metal ions is essential for life, and abnormal metabolism of metal ions in cells can impair a variety of biochemical processes, especially redox. However, current research on metal ion metabolism is still very limited. This review comprehensively examines the effects of metal ion (iron, copper, calcium, and zinc) metabolism-mediated redox homeostasis on cardiac fibrosis, outlines possible therapeutic interventions, and addresses ongoing challenges in this rapidly evolving field.

The Importance and Essentiality of Natural and Synthetic Chelators in Medicine: Increased Prospects for the Effective Treatment of Iron Overload and Iron Deficiency

The supply and control of iron is essential for all cells and vital for many physiological processes. All functions and activities of iron are expressed in conjunction with iron-binding molecules. For example, natural chelators such as transferrin and chelator-iron complexes such as haem play major roles in iron metabolism and human physiology. Similarly, the mainstay treatments of the most common diseases of iron metabolism, namely iron deficiency anaemia and iron overload, involve many iron-chelator complexes and the iron-chelating drugs deferiprone (L1), deferoxamine (DF) and deferasirox. Endogenous chelators such as citric acid and glutathione and exogenous chelators such as ascorbic acid also play important roles in iron metabolism and iron homeostasis. Recent advances in the treatment of iron deficiency anaemia with effective iron complexes such as the ferric iron tri-maltol complex (feraccru or accrufer) and the effective treatment of transfusional iron overload using L1 and L1/DF combinations have decreased associated mortality and morbidity and also improved the quality of life of millions of patients. Many other chelating drugs such as ciclopirox, dexrazoxane and EDTA are used daily by millions of patients in other diseases. Similarly, many other drugs or their metabolites with iron-chelation capacity such as hydroxyurea, tetracyclines, anthracyclines and aspirin, as well as dietary molecules such as gallic acid, caffeic acid, quercetin, ellagic acid, maltol and many other phytochelators, are known to interact with iron and affect iron metabolism and related diseases. Different interactions are also observed in the presence of essential, xenobiotic, diagnostic and theranostic metal ions competing with iron. Clinical trials using L1 in Parkinson's, Alzheimer's and other neurodegenerative diseases, as well as HIV and other infections, cancer, diabetic nephropathy and anaemia of inflammation, highlight the importance of chelation therapy in many other clinical conditions. The proposed use of iron chelators for modulating ferroptosis signifies a new era in the design of new therapeutic chelation strategies in many other diseases. The introduction of artificial intelligence guidance for optimal chelation therapeutic outcomes in personalised medicine is expected to increase further the impact of chelation in medicine, as well as the survival and quality of life of millions of patients with iron metabolic disorders and also other diseases.