Long-term donors versus non-donor men: Iron metabolism and the atherosclerotic process

Clonal hematopoiesis in frequent whole blood donors

Healthy volunteer donors are committed to contributing key medical resources. Repeated, regular donation of whole blood represents a specific trigger of hematopoietic stress. Hematopoietic stem cells (HSCs) are known to respond to environmental triggers by altering their differentiation and/or proliferative behavior. This can manifest in long-term changes in the clonal dynamics of HSCs, such as the age-associated expansion of HSCs carrying somatic mutations in genes associated with hematologic cancers-that is, clonal hematopoiesis (CH). A recent study revealed a higher prevalence of CH in frequent donors driven by low-risk mutations in genes encoding for epigenetic modifiers, with DNMT3A and TET2 being the most common. No difference in the prevalence of known preleukemic driver mutations was detected between the cohorts, underscoring the safety of repetitive blood donations. Functional analyses suggest a link between the presence of selected DNMT3A mutations found in the frequent donor group and the responsiveness of the cells to the molecular mediator of bleeding stress, erythropoietin (EPO), but not inflammation. These findings define EPO as one of the environmental factors that provide a fitness advantage to specific mutant HSCs. Analyzing CH prevalence and characteristics in other donor cohorts will be important to comprehensively assess the health risks associated with the different types of donation.

Non-Transferrin-Bound Iron in the Spotlight: Novel Mechanistic Insights into the Vasculotoxic and Atherosclerotic Effect of Iron

Significance: While atherosclerosis is an almost inevitable consequence of aging, food preferences, lack of exercise, and other aspects of the lifestyle in many countries, the identification of new risk factors is of increasing importance to tackle a disease, which has become a major health burden for billions of people. Iron has long been suspected to promote the development of atherosclerosis, but data have been conflicting, and the contribution of iron is still debated controversially. Recent Advances: Several experimental and clinical studies have been recently published about this longstanding controversial problem, highlighting the critical need to unravel the complexity behind this topic. Critical Issues: The aim of the current review is to provide an overview of the current knowledge about the proatherosclerotic impact of iron, and discuss the emerging role of non-transferrin-bound iron (NTBI) as driver of vasculotoxicity and atherosclerosis. Finally, I will provide detailed mechanistic insights on the cellular processes and molecular pathways underlying iron-exacerbated atherosclerosis. Overall, this review highlights a complex framework where NTBI acts at multiple levels in atherosclerosis by altering the serum and vascular microenvironment in a proatherogenic and proinflammatory manner, affecting the functionality and survival of vascular cells, promoting foam cell formation and inducing angiogenesis, calcification, and plaque destabilization. Future Directions: The use of additional iron markers (e.g., NTBI) may help adequately predict predisposition to cardiovascular disease. Clinical studies are needed in the aging population to address the atherogenic role of iron fluctuations within physiological limits and the therapeutic value of iron restriction approaches. Antioxid. Redox Signal. 35, 387-414.

New insights into the role of iron in inflammation and atherosclerosis

Iron is fundamental for life-essential processes. However, it can also cause oxidative damage, which is thought to trigger numerous pathologies, including cardiovascular diseases. The role of iron in the pathogenesis of atherosclerosis is still not completely understood. Macrophages are both key players in the handling of iron throughout the body and in the onset, progression and destabilization of atherosclerotic plaques. Iron itself might impact atherosclerosis through its effects on macrophages. However, while targeting iron metabolism within macrophages may have some beneficial effects on preventing atherosclerotic plaque progression there may also be negative consequences. Thus, the prevailing view of iron being capable of accelerating the progression of coronary disease through lipid peroxidation may not fully take into account the multi-faceted role of iron in pathogenesis of atherosclerosis. In this review, we will summarize the current understanding of iron metabolism in the context of the complex interplay between iron, inflammation, and atherosclerosis.

The alteration of ferritin and transferrin saturation under body mass index and blood pressure in first-time and regular male blood donors in Taiwan

Iron status, body mass index (BMI) and blood pressure (BP) are all important health indicators. In this study, ferritin and transferrin saturation levels and their correlations with BMI and BP were investigated in first-time and regular male blood donors in Taiwan. Serum ferritin and transferrin saturation values represented iron status of blood donors. Serum ferritin, serum iron, and total iron binding capacity (TIBC) were determined by chemiluminescent immunoassay sandwich method, timed-endpoint method, and turbidimetric method, respectively. Transferrin saturation was calculated as 100× serum iron/TIBC. Statistical analyses included 2-sample t test, chi-square test, Pearson correlation coefficient, and multiple linear regression. Comparisons of ferritin and transferrin saturation mean values with BMI, age, systolic blood pressure (SBP), diastolic blood pressure (DBP), and occupation were conducted. A total of 111 first-time donors and 1249 regular blood donors participated in this study. The ferritin and transferrin saturation mean values of regular male blood donors were lower than those of first-time male blood donors, but remained within the safe range. BMI was positively correlated with serum log ferritin, but not with transferrin saturation value in first-time and regular blood donors. First-time donors with BMI ≥24 kg/m and aged more than 40 years demonstrated 1.37-fold higher serum ferritin on average. Among regular donors, significant effects of BMI ≥24 kg/m and age >40 years were observed with 1.25- and 1.18-fold higher serum ferritin levels, respectively. First-time donors with SBP ≥120/DBP ≥80, ≥120/<80, and <120/≥80 mm Hg had on average 1.65-, 1.54-, and 2.59-fold higher serum ferritin levels than those with normal BP. Ferritin level was higher in BMI ≥24 kg/m subgroup than in BMI <24 kg/m subgroup among first time and regular male donors, but no difference was found in transferrin saturation values.Abnormal SBP/DBP was associated with increased ferritin level only in first-time male blood donors.