Iron Deficiency and Cardiovascular Disease: An Updated Review of the Evidence

Both low and high body iron stores relate to metabolic syndrome in postmenopausal women: Findings from the VIKING Health Study-Shetland (VIKING I)

BACKGROUND

There are conflicting results among studies on the association between serum ferritin (SF) and metabolic syndrome (MetS), and by groups of sex/menopausal status. To date, there are no studies on British populations. The SF-MetS association might be U/J-shaped. We evaluated whether SF was independently associated with MetS (harmonized definition) in people from Shetland, Scotland.

METHODS

We analysed cross-sectional data from the Viking Health Study-Shetland (589 premenopausal women [PreMW], 625 postmenopausal women [PostW] and 832 men). Logistic regressions using two approaches, one with the lowest sex and menopausal status-specific ferritin quartile (Q) as the reference and other using the middle two quartiles combined (2-3) as the reference, were conducted to estimate the SF-MetS association. The shape of the association was verified via cubic spline analyses. The associations were adjusted for age, inflammatory and hepatic injury markers, alcohol intake, smoking and BMI.

RESULTS

Prevalence of MetS was 18.3%. Among PostMW both low and high SF were associated with MetS (fully adjusted odds ratios [95% confidence interval] compared to the middle two quartiles combined were: 1.99 [1.17-3.38] p =.011 for Q1 and 2.10 [1.27-3.49] p =.004 for Q4) This U-shaped pattern was confirmed in the cubic spline analysis in PostMW with a ferritin range of 15-200 ug/L. In men, a positive association between ferritin quartiles with Q1 as the reference, did not remain significant after adjustment for BMI.

CONCLUSION

Extreme quartiles of iron status were positively associated with MetS in PostMW, while no SF-MetS associations were found in men or PreMW. The ferritin-MetS association pattern differs between populations and U/J-shaped associations may exist.

FTO alleviated ferroptosis in septic cardiomyopathy via mediating the m6A modification of BACH1

Sepsis is a global health challenge that results in systemic inflammation, oxidative stress, and multi-organ dysfunction, with the heart being particularly susceptible. This study aimed to elucidate the effect of FTO, a key regulator in m6A methylation in septic cardiomyopathy, and its potential therapeutic implications. Cellular and animal models of septic myocardial injury were established. Moreover, it was revealed that ferroptosis, which is a form of programmed necrosis occurring with iron dependence, was activated within cardiomyocytes during septic conditions. The overexpression of FTO-suppressed ferroptosis alleviated heart inflammation and dysfunction and improved survival rates in vivo. However, the protective effects of FTO were attenuated by the overexpression of BACH1, which is a molecule negatively correlated with FTO. Mechanistically, FTO modulated the m6A modification of BACH1, suggesting a complex interplay in the regulation of cardiomyocyte damage and sepsis. Our findings reveal the potential of targeting the FTO/BACH1 axis and ferroptosis inhibitors as therapeutic strategies for sepsis-induced cardiac injuries.

Knowledge and practices in preventing nutritional anaemia of the urban poor adolescents in Kuala Lumpur, Malaysia

Background: Anaemia has been identified as a major public health problem that affects both developed and developing countries, including Malaysia. To prevent anaemia, knowledge is a key parameter for changing attitudes and practices. Aim: This present study aims to determine the association of knowledge and practices in preventing nutritional anaemia with anaemia status of urban poor adolescents in Kuala Lumpur, Malaysia. Methods: A total of 209 urban poor adolescents (50.7% males and 49.3% females) aged 10 to 17 years old were recruited from eight low-cost flats (People Housing Programme) in Kuala Lumpur, Malaysia. A self-administered questionnaire was used to assess the sociodemographic characteristics, knowledge and practices in preventing nutritional anaemia. Anaemia status from the haemoglobin level concentration was determined using HemoCue® 201  +  hemoglobinometer. Results: The prevalence of anaemia among urban poor adolescents was 58.4%, particularly prevalent among females (p < 0.001) and household size of six and above (p  =  0.036). Only 29.2% and 10.0% of them were found to have good levels of knowledge and practices in preventing nutritional anaemia, respectively. Adolescents with high knowledge level tended to be anaemic as compared to poor knowledge level (AOR(95% CI)  =  2.20 (1.02, 5.61), p < 0.05) after adjusting for sex, household size and monthly household income. Conclusion: Findings showed high prevalence of anaemia and low levels of knowledge and practices of nutritional anaemia prevention among the urban poor adolescents. Nutrition education and intervention are needed to improve the anaemia status of the urban poor adolescents.

Cross-sectional and longitudinal associations of Iron biomarkers and cardiovascular risk factors in pre- and postmenopausal women: leveraging repeated measurements to address natural variability

BACKGROUND

The association between iron biomarkers and cardiovascular disease risk factors (CVD-RFs) remains unclear. We aimed to (1) evaluate the cross-sectional and longitudinal associations between iron biomarkers (serum ferritin, transferrin saturation (TSAT), transferrin) and CVD-RFs among women, and (2) explore if these associations were modified by menopausal status.

METHOD

Cross-sectional and longitudinal analyses including 2542 and 1482 women from CoLaus cohort, respectively. Multiple linear regression and multilevel mixed models were used to analyse the associations between Iron biomarkers and CVD-RFs. Variability of outcomes and iron markers between surveys was accessed using intraclass correlation (ICC).

RESULTS

After multivariable adjustment, elevated serum ferritin levels were associated with increased insulin and glucose levels, while higher transferrin levels were linked to elevated glucose, insulin and total cholesterol, and systolic and diastolic blood pressure (p < 0.05). No association was observed between CVD-RFs and TSAT (p > 0.05). Iron biomarkers demonstrated low reliability across reproductive stages but exhibited stronger associations in the perimenopausal group. In longitudinal analysis, we found association only for transferrin with lower glucose levels [β = - 0.59, 95% CI (- 1.10, - 0.08), p = 0.02] and lower diastolic blood pressure [β = - 7.81, 95% CI (- 15.9, - 0.56), p = 0.04].

CONCLUSION

In cross-sectional analysis, transferrin was associated with several CVD-RFs, and the associations did not change according to menopausal status. Conversely, in the longitudinal analyses, changes in transferrin were associated only with lower glucose and diastolic blood pressure levels. These differences might stem from the substantial longitudinal variation of iron biomarkers, underscoring the need for multiple iron measurements in longitudinal analyses.

The complementary roles of iron and estrogen in menopausal differences in cardiometabolic outcomes

Biological hormonal changes are frequently cited as an explanatory factor of sex and menopause differences in cardiometabolic diseases (CMD) and its associated risk factors. However, iron metabolism which varies between sexes and among women of different reproductive stages could also play a role. Recent evidence suggest that iron may contribute to CMD risk by modulating oxidative stress pathways and inflammatory responses, offering insights into the mechanistic interplay between iron and CMD development. In the current review, we provide a critical appraisal of the existing evidence on sex and menopausal differences in CMD, discuss the pitfall of current estrogen hypothesis as sole explanation, and the emerging role of iron in CMD as complementary pathway. Prior to menopause, body iron stores are lower in females as compared to males, but the increase during and after menopause, is tandem with an increased CMD risk. Importantly, basic science experiments show that an increased iron status is related to the development of type 2 diabetes (T2D), and different cardiovascular diseases (CVD). While epidemiological studies have consistently reported associations between heme iron intake and some iron biomarkers such as ferritin and transferrin saturation with the risk of T2D, the evidence regarding their connection to CVD remains controversial. We delve into the factors contributing to this inconsistency, and the limitation of relying on observational evidence, as it does not necessarily imply causation. In conclusion, we provide recommendations for future studies on evaluating the potential role of iron in elucidating the sex and menopausal differences observed in CMD.

Long-term dietary iron intake and risk of non-fatal cardiovascular diseases in the China Health and Nutrition Survey

AIMS

We aimed to investigate the association of long-term dietary iron intake with the risk of non-fatal cardiovascular diseases (CVDs), myocardial infarction (MI), and stroke in Chinese populations with predominantly plant-based diets by sex.

METHODS AND RESULTS

A total of 17 107 participants (8569 men and 8538 women) aged 18-80 years in the China Health and Nutrition Survey (CHNS) 1989-2015 were included. Dietary intake was assessed repeatedly by three consecutive 24-h dietary recalls. Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). During a median follow-up of 11.1 years, the adjusted HRs (95% CIs) for non-fatal CVDs risk across quintiles of total iron intake in men were 1.00, 0.65 (0.46-0.93), 0.54 (0.37-0.78), 0.66 (0.46-0.94), 0.69 (0.47-1.03), but no significant association in women. Similar associations were found for stroke risk, but not for MI risk. The dose-response curves for the association of total iron and non-heme iron intake with the risk of non-fatal CVDs and stroke followed a reverse J-shape only in men and similar reverse J-shaped association of heme iron intake with non-fatal CVDs and stroke risk in both men and women (P-non-linearity <0.05).

CONCLUSION

Moderate dietary iron intake may protect against non-fatal CVDs and stroke, especially in Chinese men consuming plant-based diets. Both quantity and quality of dietary iron intake should be considered in the prevention of non-fatal CVDs due to differences in dietary patterns among diverse populations.

Vagus nerve stimulation and acetylcholinesterase inhibitor donepezil provide cardioprotection against trastuzumab-induced cardiotoxicity in rats by attenuating mitochondrial dysfunction

Trastuzumab (Trz) is a targeted anticancer drug for human epidermal growth factor receptor 2 (HER2)-positive tumors, as Trz-induced cardiotoxicity (TIC) is commonly observed in Trz-treated patients. Since cardiac autonomic modulation with electrical vagus nerve stimulation (VNS) and acetylcholinesterase (AChE) inhibitors exerts cardioprotection against various heart diseases, the comparative effects of electrical VNS and an AChE inhibitor (donepezil) on cardiac and mitochondrial functions and programmed cell death pathways in TIC are not known. VNS devices were implanted in thirty-two male Wistar rats and were divided into 4 groups: (i) Control-Sham (CSham), (ii) Trz-Sham (TSham), (iii) Trz-VNS (TVNS), and (iv) Trz-donepezil (TDPZ). Rats in the Trz-treated groups were intraperitoneally injected with Trz (4 mg/kg/day) for 7 days, while CSham rats were injected with NSS. VNS devices were activated in the TVNS rats during the 7-day Trz treatment, but not in the sham rats. Rats in the TDPZ group received donepezil orally (5 mg/kg/day) for 7 days. At the end, left ventricular (LV) function and heart rate variability were evaluated, and heart tissue was collected for biochemical and histological analysis. Trz rats showed LV dysfunction and cardiac sympathovagal imbalance. In addition, mitochondrial function and dynamics were impaired in TIC rats. Trz also increased cardiomyocyte death by inducing apoptosis, pyroptosis, and ferroptosis. Electrical VNS and donepezil had similar efficacy in alleviating cardiac mitochondrial dysfunction, dynamic imbalances, and cardiomyocyte death, leading to improved LV function. These findings suggested that parasympathetic activation via either VNS or an AChE inhibitor could be a promising therapeutic intervention against TIC.

Association between latent profile of dietary intake and cardiovascular diseases (CVDs): Results from Fasa Adults Cohort Study (FACS)

Cardiovascular diseases (CVDs) have been among the most significant non-communicable diseases. Dietary risks account for the most cause of CVDs mortalities. Evaluating overall dietary patterns (through the Latent profile of dietary intake) can provide a more accurate prediction regarding the prevalence of CVDs. The present cross-sectional study aimed to investigate the relationship between the latent profile of dietary intake and CVDs prevalence. The population of the Fasa Adults Cohort Study was employed to gather the data (n = 8319). A modified FFQ was employed to assess eating behaviors. Minerals, as well as the energy intake and total fiber, were measured using Nutritionist IV software (version 7.0). To estimate the prevalence of CVDs, accurate records of patients' histories were made. Individuals were clustered according to their dietary intake using latent profile analysis. The mean age was 48.75 ± 9.59 years, and 53.28% (4430) were women. 63.9% of participants with low Socioeconomic Status (SES) were in the low-intake profile (P < 0.001), and high SES increases the odds of being in the high-intake profile (ORhigh/low = 2.87, 95% CI 2.55-3.24). The low-intake group had the lowest amount of physical activity (Met) (P < 0.001). The result of multivariate logistic regression revealed that categorized in the low-intake group significantly increased the development of CVDs (OR = 1.32, 95% CI 1.07-1.63, P = 0.010). The mean micronutrients and total fiber, in individuals with a low intake profile, were significantly lower than other groups (P < 0.001). Overall, we estimated that a low intake of all food groups increases the odds of developing CVDs significantly.

The effect of circulating iron on barrier integrity of primary human endothelial cells

Iron is hypothesized to be one of the contributors to cardiovascular disease and its levels in the circulation may correlate with cardiovascular risk. The aim of this study is to investigate the mechanisms that underlie the effects of iron on the barrier function of primary human endothelium. We used Human Umbilical Vein Endothelial Cells (HUVEC) to investigate the effects of Fe3+ using electric cell-substrate impedance sensing, microscopy, western blot and immunofluorescence microscopy. Exposure to Fe3+ caused EC elongation and upregulation of stress-induced proteins. Analysis of barrier function showed a dose-dependent drop in endothelial integrity, which was accompanied by Reactive Oxygen Species (ROS) production and could partly be prevented by ROS scavengers. Inhibition of contractility by the ROCK inhibitor Y27632, showed even more effective rescue of barrier integrity. Using western blot, we detected an increase in expression of the small GTPase RhoB, an inducer of EC contraction, and a small decrease in VE-cadherin, suggestive for an iron-induced stress response. Co-stimulation by TNFα and iron, used to investigate the role of low-grade inflammation, revealed an additive, negative effect on barrier integrity, concomitant with an upregulation of pro-inflammatory markers ICAM-1 and RhoB. Iron induces a response in HUVEC that leads to endothelial activation and a pro-inflammatory state measured by loss of barrier integrity which can be reversed by ROS scavengers, combined with inhibition of contractility. These data suggest that ROS-mediated damage of the vascular endothelium could contribute to the increased cardiovascular risk which is associated with elevated levels of circulating iron.

Understanding the Interplay between Iron Deficiency and Congestive Heart Failure: A comprehensive review

Iron is an essential micronutrient for abounding physiological processes in the body, and its deficiency can be caused by various factors, such as low iron intake due to economic difficulties or loss of appetite, decreased iron absorption due to gastrointestinal issues, or increased iron loss due to hemorrhages or proteinuria. Iron deficiency is a prevalent issue among heart failure (HF) patients and is a significant contributor to anemia, affecting 30-50% of patients regardless of their gender, ethnicity, or left ventricular ejection fraction. Individuals with HF have high levels of pro-inflammatory cytokines, which can inhibit erythropoiesis by degrading the membrane iron exporter ferroportin, mediated by an increased release of hepcidin. In addition, elevated sympathetic and renin-angiotensin-aldosterone system activity retains salt and water, resulting in high cardiac output HF in people with normal left ventricular function. This review provides an overview of iron deficiency and HF.

Iron status and cardiometabolic risk in children

AIM

We aimed to evaluate associations between serum ferritin and transferrin and variables related to the metabolic syndrome (MetS) in children.

METHODS

Cross-sectional and longitudinal study in prepubertal children(n=832) aged 3-14 years. A subset(n=203) were re-examined after a mean follow-up of 3.7±0.8 years[range 2-6]. Outcomes were MetS and MetS components scores, glycosylated haemoglobin (HbA1c), and their follow-up change.

RESULTS

Children with low ferritin had increased HbA1c Z scores (ANCOVA,P=0.003). Ferritin was inversely associated with glycaemia [fully adjusted β (95% confidence interval): -2.35(-4.36 to -0.34)]. Transferrin was associated with diastolic blood pressure[β: 0.02(0.01-0.04)] and log-HOMA-IR [β:0.001(0.0005-0.002)]. MetS risk score worsened during follow-up in children with the lowest baseline ferritin levels. In contrast, at baseline ferritin was positively associated with all (except glycaemia) the MetS-related variables but adjustments for inflammatory, hepatic function, and body mass markers attenuated those associations(P>0.05).

CONCLUSIONS

Lower iron status was independently associated with glycaemic markers and MetS in children, whereas higher ferritin levels were related to other cardiometabolic risk markers under the influence of inflammation, hepatic injury and body mass. Research is required to study whether this mixed pattern is part of an early risk or would be explained by a normal transition during growth and development.

Association Between Ferritin Levels and Altitude-Dependent Cardiorespiratory Fitness in Mountain Guides

Pühringer, Reinhard, Martina Muckenthaler, and Martin Burtscher. Association between ferritin levels and altitude-dependent cardiorespiratory fitness in mountain guides. High Alt Med Biol. 24:139-143, 2023. Background: Higher ferritin levels may be associated with lower cardiorespiratory fitness (CRF; i.e., maximal oxygen uptake, VO2max) and may represent early markers of cardiovascular risk but may also support high-altitude acclimatization. To evaluate these potential associations, data recordings from a large sample of male mountain guides have been analyzed. Methods: A total of 154 data sets (including anthropometric data, VO2max, blood lipids, hemoglobin, ferritin, and transferrin levels) of regularly physically active and well-acclimatized mountain guides were available for analyses. Participants performed equal incremental cycle ergometer tests to exhaustion at low (600 m) and (∼1 week later) at moderate altitude (2,000 m). Results: Ferritin levels were positively correlated with levels of hemoglobin (r = 0.29, p < 0.01), total cholesterol (r = 0.18, p < 0.05), triglycerides (r = 0.23, p < 0.01), and low-density lipoprotein (r = 0.22, p < 0.01), and negatively with high-density lipoprotein levels (r = -0.16, p < 0.05) and also with baseline (taken at low altitude) VO2max values (r = -0.19, p < 0.05). In contrast, higher ferritin levels were associated with less VO2max decline from low-to-moderate altitude (r = 0.26, p < 0.01). Conclusion: Higher ferritin levels in male mountain guides are weakly associated with lower CRF and higher prevalence of cardiovascular risk factors but with slightly less reduction in VO2max when acutely exposed to moderate altitude. The clinical relevance of these observations needs further investigation.

Role of Mitochondrial Iron Overload in Mediating Cell Death in H9c2 Cells

Iron overload (IO) is associated with cardiovascular diseases, including heart failure. Our study's aim was to examine the mechanism by which IO triggers cell death in H9c2 cells. IO caused accumulation of intracellular and mitochondrial iron as shown by the use of iron-binding fluorescent reporters, FerroOrange and MitoFerroFluor. Expression of cytosolic and mitochondrial isoforms of Ferritin was also induced by IO. IO-induced iron accumulation and cellular ROS was rapid and temporally linked. ROS accumulation was detected in the cytosol and mitochondrial compartments with CellROX, DCF-DA and MitoSOX fluorescent dyes and partly reversed by the general antioxidant N-acetyl cysteine or the mitochondrial antioxidant SkQ1. Antioxidants also reduced the downstream activation of apoptosis and lytic cell death quantified by Caspase 3 cleavage/activation, mitochondrial Cytochrome c release, Annexin V/Propidium iodide staining and LDH release of IO-treated cells. Finally, overexpression of MitoNEET, an outer mitochondrial membrane protein involved in the transfer of Fe-S clusters between mitochondrial and cytosol, was observed to lower iron and ROS accumulation in the mitochondria. These alterations were correlated with reduced IO-induced cell death by apoptosis in MitoNEET-overexpressing cells. In conclusion, IO mediates H9c2 cell death by causing mitochondrial iron accumulation and subsequent general and mitochondrial ROS upregulation.

The role of iron metabolism in chronic diseases related to obesity

Obesity is one of the major public health problems threatening the world, as well as a potential risk factor for chronic metabolic diseases. There is growing evidence that iron metabolism is altered in obese people, however, the highly refined regulation of iron metabolism in obesity and obesity-related complications is still being investigated. Iron accumulation can affect the body’s sensitivity to insulin, Type 2 diabetes, liver disease and cardiovascular disease. This review summarized the changes and potential mechanisms of iron metabolism in several chronic diseases related to obesity, providing new clues for future research.

Association between iron status and incident coronary artery disease: a population based-cohort study

Disorders of iron metabolism has been implicated in cardiovascular disease. However, the association of serum iron stores and coronary artery disease (CAD) remains inconsistent. Here, we investigated the associations of serum iron metabolism with the incidence of CAD, the severity of coronary artery stenosis, metabolic biomarkers, and the risk of major adverse cardiovascular event (MACE). A total of 643 CAD patients and 643 healthy controls were enrolled to assess the associations of serum iron status with the presence of CAD, the severity of CAD, and the risk of MACE. Serum iron metabolism and other metabolic markers were measured in all subjects. All statistical analyses were analyzed using SPSS22.0 software and STATA statistical package. Serum level of iron metabolism markers, including serum iron, unsaturated transferrin iron binding capacity (UIBC), Total iron binding capacity (TIBC) levels, in CAD groups was significantly lower than the control group (P < 0.001). UIBC and TIBC were negatively correlated with ferritin in both sexes. Each unit increase of serum iron and TIBC were found to have a protective role for CAD in women (iron: OR 0.794, 95% CI (0.647-0.973), TIBC: OR 0.891, 95% CI (0.795-0.999), P < 0.05). However, high ferritin level was significant associated the CAD incident in both sexes (OR 1.029, 95% CI (1.002-1.058) in men, OR 1.013, 95% CI (1.0-1.025) in women, P < 0.05). Serum iron metabolism markers exhibited no significant association with the severity of CAD. Increased serum level of iron and TIBC levels were found to have a protective role for CAD in women, but not in men. Elevated serum ferritin is independently and positively associated with CAD in men and women.

Effect of losartan potassium, metformin hydrochloride, and simvastatin on in vitro bioaccessibility of Cu, Fe, Mn, and Zn in oat flour from Brazil

BACKGROUND

The simultaneous administration of drugs with food can compromise the bioaccessibility and absorption of nutrients. The objective of this study was to evaluate the influence of the use of losartan potassium (LP), metformin hydrochloride (MH), and simvastatin (S) on the in vitro bioaccessibility of micronutrients (Cu, Fe, Mn, and Zn) in oat flour from Bahia, Brazil.

METHODS

The experimental procedure consisted of the in vitro extraction of the bioaccessible fraction of Cu, Fe, Mn, and Zn in oat flour-with and without LP (50 mg), MH (500 mg), and S (20 mg)-using the unified bioaccessibility method (UBM), simulating the conditions of the gastrointestinal tract. For decomposition of the samples (oat flour and residue), a digester block with a closed system was used. To determine the total content (flour and residual fraction) and bioaccessible micronutrients, inductively coupled plasma optical emission spectrometry (ICP OES) was used.

RESULTS

The bioaccessible contents (µg g^-1) without the addition of drugs were: Cu 5.86 ± 0.21, Fe 32.80 ± 1.32, Mn 87.90 ± 1.90, and Zn 30.33 ± 2.05, with bioaccessibility ranging from 31.5 % for Fe to 99 % for Mn. The in vitro extraction method was validated by mass balance with recovery values from 89.78 % for Cu to 101.94 % for Mn. The range of bioaccessible contents (µg g^-1) were: Cu (<4.14), Fe (32.10 ± 0.20-54.10 ± 2.03), Mn (81.40 ± 0.93-93.22 ± 0.80), and Zn (<10.80-29.11 ± 2.20). The estimation of the bioaccessibility of Cu, Mn, and Zn in oat flour were compromised in the presence of LP, MH, and S (p < 0.05).

CONCLUSION

Chemical interactions can occur between drugs and micronutrients. Taken together, our results highlight that LP, MH, and S can interfere with the bioaccessibility of Cu, Fe, Mn, and Zn in oat flour in patients who use these drugs, suggesting its rational use in further investigations.

Increased Serum Soluble Transferrin Receptor Levels Were Associated With High Prevalence of Cardiovascular Diseases: Insights From the National Health and Nutrition Examination Survey 2017–2018

Background: Iron deficiency is common in cardiovascular diseases (CVD), e.g., heart failure and coronary heart disease. Soluble transferrin receptor (sTfR) is a promising marker representing unmet cellular iron demands. However, whether higher serum sTfR is associated with increased risk of CVDs needs further investigation.

Methods: In the present cross-sectional study, we analyzed data of 4,867 adult participants of the National Health and Nutrition Examination Survey (NHANES) 2017–2018. Linear regression models were employed to identify possible correlations between sTfR and other characteristics. The association between sTfR and CVDs was assessed with univariable and multivariable logistics regression models.

Results: The prevalence of CVDs was 9.5% among participants, and higher sTfR levels were found in participants with CVDs (p < 0.001). Linear regression models revealed positive associations between sTfR and age, body mass index, systolic blood pressure, glycated hemoglobulin A1c, and insulin resistance (all p < 0.001). In the multivariable logistics regression model, the adjusted odds ratio of sTfR for CVDs was 2.05 (per 1 log₂ mg/L, 95% confidence interval: 1.03∼4.05, p = 0.046). Further subgroup analysis identified the associations of sTfR and CVDs were only significant in participants ≥60 years old, or with hypertension (all p < 0.05).

Conclusion: Our study demonstrated that increased serum sTfR levels were associated with a high prevalence of cardiovascular diseases.

Signaling Integration of Hydrogen Sulfide and Iron on Cellular Functions

Significance: Hydrogen sulfide (H₂S) is an endogenous signaling molecule, regulating numerous physiological functions from vasorelaxation to neuromodulation. Iron is a well-known bioactive metal ion, being the central component of hemoglobin for oxygen transportation and participating in biomolecule degradation, redox balance, and enzymatic actions. The interplay between H₂S and iron metabolisms and functions impacts significantly on the fate and wellness of different types of cells. Recent Advances: Iron level in vivo affects the production of H₂S via nonenzymatic reactions. On the contrary, H₂S quenches excessive iron inside the cells and regulates the redox status of iron. Critical Issues: Abnormal metabolisms of both iron and H₂S are associated with various conditions and diseases such as iron overload, anemia, oxidative stress, and cardiovascular and neurodegenerative diseases. The molecular mechanisms for the interactions between H₂S and iron are unsettled yet. Here we review signaling links of the production, metabolism, and their respective and integrative functions of H₂S and iron in normalcy and diseases. Future Directions: Physiological and pathophysiological importance of H₂S and iron as well as their therapeutic applications should be evaluated jointly, not separately. Future investigation should expand from iron-rich cells and tissues to the others, in which H₂S and iron interaction has not received due attention. Antioxid. Redox Signal. 36, 275-293.

Herceptin induces ferroptosis and mitochondrial dysfunction in H9c2 cells

Ferroptosis has been previously implicated in the pathological progression of cardiomyopathy. Herceptin (trastuzumab), which targets HER2, is commonly applied for the treatment of HER2⁺ breast cancer. However, its clinical use is limited by its cardiotoxicity. Therefore, the present study aimed to investigate if targeting ferroptosis could protect against Herceptin‑induced heart failure in an in vitro model of H9c2 cells after treatment of Herceptin, Herceptin + ferroptosis inhibitor ferrostatin‑1 (Fer‑1) or Herceptin + Deferoxamine. H9c2 cell viability was measured by MTT assay. Reactive oxygen species (ROS) levels were detected by measuring the fluorescence of DCFH‑DA‑A and MitoSOX™ Red. Glutathione (GSH)/oxidized glutathione (GSSG) ratio was measured using the GSH/GSSG Ratio Detection Assay kit. Mitochondrial membrane potential and ATP content were evaluated by JC‑1 staining and bioluminescent assay kits, respectively. Protein expressions of glutathione peroxidase 4, recombinant solute carrier family 7 member 11, mitochondrial optic atrophy1‑1/2, mitofusin, Acyl‑CoA synthetase long chain family member 4, cytochrome c, voltage‑dependent anion‑selective channel, dynamin‑related protein, mitochondrial fission 1 protein and mitochondrial ferritin were evaluated by western blotting. It was found that Herceptin reduced H9c2 cell viability whilst increasing intracellular and mitochondrial ROS levels in a dose‑ and time‑dependent manner. Furthermore, Herceptin decreased glutathione peroxidase (GPX) protein expression and the GSH/ GSSG ratio in H9c2 cells in a dose‑ and time‑dependent manner. The Fer‑1 abolished this Herceptin‑induced reduction in cell viability, GSH/GSSG ratio, mitochondrial membrane potential and ATP content. Fer‑1 also reversed the suppressive effects of Herceptin on the protein expression levels of GPX4, recombinant solute carrier family 7 member 11, mitochondrial optic atrophy1‑1/2 and mitofusin in H9c2 cells. Subsequently, Fer‑1 was found to reverse the Herceptin‑induced increase in mitochondrial ROS and iron levels in H9c2 cells, as well as the increased protein expression levels of Acyl‑CoA synthetase long chain family member 4, cytochrome c, voltage‑dependent anion‑selective channel, dynamin‑related protein, mitochondrial fission 1 protein and mitochondrial ferritin in H9c2 cells. However, compared with deferoxamine, an iron chelator, the effects of Fer‑1 were less effective. Collectively, these findings provided insights into the pathogenic mechanism that underlie Herceptin‑induced cardiomyopathy, which potentially provides a novel therapeutic target for the prevention of cardiotoxicity in HER2⁺ breast cancer treatment.

Certain Associations Between Iron Biomarkers and Total and γ' Fibrinogen and Plasma Clot Properties Are Mediated by Fibrinogen Genotypes

Introduction: Evidence for the relationship between body iron and cardiovascular disease (CVD) is inconsistent and mechanisms involved remain poorly understood. Therefore, we first investigated whether there are linear or non-linear relationships between iron status and total and γ' fibrinogen as well as plasma fibrin clot properties and, second, determined whether there are interactions with iron biomarkers and fibrinogen and FXIII single nucleotide polymorphisms (SNPs) in relation to fibrinogen concentration and functionality. Methods: In this cross-sectional analysis of 2,010 apparently healthy Black South Africans we quantified total and γ' fibrinogen, serum iron, ferritin and transferrin using standardized methods and calculated transferrin saturation (TS). Clot architecture and lysis were explored with a global analytical turbidity assay. The SNPs were determined through an Illumina BeadXpress^® platform. Results: Total, but not %γ', fibrinogen negatively correlated with serum iron concentrations, although both decreased over iron tertiles. %γ' fibrinogen correlated negatively with transferrin and decreased over the transferrin tertiles. A weak negative association between total fibrinogen and TS was detected with fibrinogen decreasing over the TS tertiles and categories based on TS. Lag time correlated positively with transferrin and increased over transferrin tertiles, when adjusting for fibrinogen. Before adjusting for fibrinogen, lag time was shorter in those with adequate iron status based on TS than other iron subcategories. Clot lysis time (CLT) negatively correlated with ferritin and was longer in the first than in the third ferritin tertile. Among iron status categories based on ferritin, only CLT differed and was longer in those with adequate iron than with iron-overload. CLT negatively correlated with TS, albeit weakly, shortened over the TS tertiles and was shorter in those with adequate iron based on TS categories. Interactions were observed between FGB SNPs and some of the markers of iron status investigated, in relation to the clot properties with the most prominent associations detected in homozygous carriers of the variant alleles for whom increased iron status was more beneficial than for those harboring the wild-type alleles. Iron modulated the influence of the SNPs so that for the majority iron was beneficial in respect of clot properties, but even more so for a minority group harboring specific variant alleles. Conclusion: This is the first large-scale epidemiological study to relate fibrinogen concentration and functionality to markers of iron status and to take genetic factors into consideration. We have detected a relationship between iron biomarkers and fibrinogen as well as clot characteristics that are influenced by the genetic make-up of an individual.

Comparison of Iron Profile in Patients With and Without Coronary Heart Disease

Introduction Atherosclerosis is considered a major cause of coronary artery disease (CAD). Pathogenesis of atherosclerosis involves the oxidation of low-density lipoprotein (LDL) within the lysosomes of macrophages. Ferritin and iron have pro-oxidant properties, and ferritin is an independent positive determinant of oxidized LDL level. In this study, we will determine the association between ferritin and serum iron levels and CAD. Methods This case-control study was conducted in the cardiology unit of a tertiary care hospital in Pakistan from December 2020 to April 2021. After taking informed consent, 400 patients with a confirmed diagnosis of CAD were enrolled. Another set of 400 patients without a history of CAD were included in the control group. A blood sample of 5 ml was drawn and sent to the laboratory to test for ferritin, serum iron, and total iron-binding capacity (TIBC). Ferritin, serum iron, and iron-binding capacity were compared between the case and control groups.  Results Serum ferritin was significantly higher in patients with CAD compared to patients without CAD (921.21 ± 201.21 ug/L vs. 101.21 ± 92.21 ug/L; p-value: <0.0001). Serum TIBC was significantly lower in patients with CAD compared to patients without CAD (302.12 ± 101.75 umol/L vs. 362.12 ± 82.16 umol/L). Conclusion Patients with raised levels of ferritin should consult a physician to manage their ferritin levels since they are at a greater risk of CAD. Treatment ranges from lifestyle changes to pharmacological therapy, thus reducing the overall risk and normalizing the ferritin levels.

Hepcidin Gene Cloning and Expression Pattern in Turbot (Scophthalmus maximus) after Vibrio. anguillarum Infection

BACKGROUND

Antimicrobial peptides play crucial roles in organisms as the first line of defense against invading pathogens.

OBJECTIVE

To isolate the hepcidin (hepc1) gene from the liver of turbot (Scophthalmus maximus) challenged with Vibrio anguillarum (GenBank accession number: AM113708), characterize it, and assess its expression level in various tissues.

MATERIALS AND METHODS

The DNA sequence of hepcidin from S. maximus was determined from the total RNA extracted and reverse transcribed from this fish. The expression levels of tissue-specific hepcidin transcripts were determined using reverse-transcriptase polymerase chain reactions.

RESULTS

Hepcidin levels increased in the livers, head kidneys and spleens of the fish. The transcriptional increase was especially noticeable in the liver after bacterial infection commencement. The presence of hepcidin and interleukin-beta (IL-1β) in blood leukocytes was compared at the transcription level and hepcidin transcripts were detected earlier than IL-1β transcripts after infection, indicating that hepcidin might serve as the first line of defense to kill bacteria and may also play a more direct and effective role than that of IL-1β during the initial stage of the innate immune response when turbot are exposed to bacteria invasion.

CONCLUSIONS

Hepcidin might serve as the first line of defense to kill bacteria and may also play a more direct and effective role than that of IL-1β during the initial stage of the innate immune response when turbot are exposed to bacteria invasion.

Low serum iron levels and risk of cardiovascular disease in high risk elderly population: Nested case-control study in the PREvención con DIeta MEDiterránea (PREDIMED) trial

BACKGROUND & AIMS

Epidemiological data on iron status and cardiovascular disease (CVD) are still controversial. The aim of this study was to determine whether low serum iron (SI) levels are associated with an increased odds of first CVD event in a population at high cardiovascular risk.

METHODS

Case-control study design nested within the "PREvención con DIeta MEDiterránea" (PREDIMED) trial. A total of 207 participants diagnosed with CVD (myocardial infarction, stroke or cardiovascular death) during follow-up period (2003-2010) were matched by sex, age and intervention group to 436 controls by incidence density sampling. Median time between serum sample collection and subsequent CVD event occurrence was 0.94 years. Inductively coupled plasma mass spectrometry analysis was used to determine SI levels. In-person interviews, medical record reviews, and validated questionnaires were used to assess covariates. Multivariable-adjusted odds ratios (ORs) of CVD were calculated with conditional logistic regression.

RESULTS

Mean SI levels were higher in men than in women (1224.0 μg/L vs. 1093.8 μg/L; p < 0.001). Among women, but not in men, the mean SI concentration was lower in cases than in controls (1008.5 μg/L vs. 1132.9 μg/L; p = 0.030). There was a gradual decrease in the multivariable-adjusted ORs of CVD with increasing SI levels (highest vs. lowest quartile: OR = 0.55, 95% CI: 0.32-0.93; p_trend = 0.020). This inverse relationship was more pronounced among women (highest vs. lowest quartile: OR = 0.15, 95% CI: 0.03-0.69; p_trend = 0.011).

CONCLUSIONS

The present findings are consistent with previously reported inverse associations between SI and CVD. SI levels as an independent marker of short-term cardiovascular risk may be useful for risk assessment in older populations.

TRIAL REGISTRATION

www.controlled-trials.com; International Standard Randomized Controlled Trial Number (ISRCTN): 35,739,639. Registered 5 October 2005. Retrospectively registered.

Validation of a food frequency questionnaire as a tool for assessing dietary intake in cardiovascular disease research and surveillance in Bangladesh

BACKGROUND

Cardiovascular disease (CVD) has emerged as a major public health concern in Bangladesh. Diet is an established risk factor for CVD but a tool to assess dietary intake in Bangladesh is lacking. This study aimed to validate a food frequency questionnaire (FFQ) using the 24-h dietary recall method and corresponding nutritional biological markers among rural and urban populations of Bangladesh.

METHOD

Participants of both genders aged 18-60 years were included in the analysis (total n = 146, rural n = 94 and urban n = 52). Two FFQs of 166 items were administered three-months apart, during which time three 24-h dietary recalls were also completed. Participants were asked to recall their frequency of consumption over the preceding 3 months. Urine and blood samples were collected for comparison between FFQ-estimates of nutrients and their corresponding biomarkers. Methods were compared using unadjusted, energy-adjusted, de-attenuated correlation coefficients, 95% limits of agreement (LOA) and quartile classification.

RESULTS

Fair to moderate agreement for ranking energy, macro and micronutrients into quartiles was observed (weighted k value ranged from 0.22 to 0.58; p < 0.001 for unadjusted data) except for vitamin D (weighted k - 0.05) and zinc (weighted k 0.09). Correlation coefficients of crude energy, macronutrients and common micronutrients including vitamin E, thiamine, riboflavin, niacin, pyridoxine, folate, iron, magnesium, phosphorus, potassium, and sodium were moderately good, ranging from 0.42 to 0.78; p < 0.001 but only fair for vitamin A, β carotene and calcium (0.31 to 0.38; p < 0.001) and poor for vitamin D and zinc (0.02 and 0.16; p = ns, respectively). Energy-adjusted correlations were generally lower except for fat and vitamin E, and in range of - 0.017 (for calcium) to 0.686 (for fat). De-attenuated correlations were higher than unadjusted and energy- adjusted, and significant for all nutrients except for vitamin D (0.017) to 0.801 (for carbohydrate). The Bland Altman tests demonstrated that most of the coefficients were positive which indicated that FFQ provided a greater overestimation at higher intakes. More than one in three participants appeared to overestimate their food consumption based on the ratio of energy intake to basal metabolic rate cut points suggested by Goldberg. Absolute intake of macronutrients was 1.5 times higher and for micronutrients it ranged from 1.07 (sodium) to 26 times (Zinc). FFQ estimates correlated well for sodium (0.32; p < 0.001), and vitamin D (0.20; p = 0.017) with their corresponding biomarkers and iron (0.25; p = 0.003) with serum ferritin for unadjusted data. Folate, iron (with haemoglobin) and total protein showed inverse association; and fat and potassium showed poor correlation with their corresponding biomarkers for unadjusted data. However, folate showed significant positive correlation (0.189; p = 0.025) with biomarker after energy adjustment.

CONCLUSION

Although FFQ showed overestimation for absolute intake in comparison with 24-h recalls, the validation study demonstrated acceptable agreement for ranking dietary intakes from FFQ with 24-h recall methods and some biomarkers and therefore could be considered as a tool to measure dietary intake for research and CVD risk factors surveillance in Bangladesh. The instrument may not be appropriate for monitoring population adherence to recommended intakes because of the overestimation.

Supplemental Vitamins and Minerals for Cardiovascular Disease Prevention and Treatment

PURPOSE OF REVIEW

The objective of this study is to explore the current literature supporting the use oral multivitamins and multi/minerals (OMVMs) for cardiovascular diseases (CVD) treatment and prevention.

RECENT FINDINGS

Data on multivitamins, vitamin C and D, coenzyme Q, calcium, and selenium, has showed no consistent benefit for the prevention of CVD, myocardial infarction, or stroke, nor was there a benefit for all-cause mortality to support their routine supplementation. Folic acid alone and B vitamins with folic acid, B₆ and B₁₂, reduce stroke, whereas niacin and antioxidants are associated with an increased risk of all-cause mortality. Iron deficiency should be avoided and treated if found, but routine supplementation to those without deficiency is not evidence based. Despite the high supplement use by the general public, there is no evidence to support the routine supplementation of oral multivitamins and multi/minerals (OVMN) for CVD prevention or treatment.

Iron hypothesis and coronary artery disease in geriatric patients

Context and aims: Iron is a pro-oxidant factor in the pathogenesis of CAD. The association of body iron status was investigated relative to the occurrence and severity of CAD.Design and methods: The subjects consisted of 110 males and 115 females who were classified as either a CAD case or a control according to the results of coronary angiography.Results: A new parameter, the "serum free iron index," was defined as the ratio of serum iron to UIBC. The level of ferritin showed significant increase [97.2 (67.0-171.2) µg/L vs. 85.6 (52.5-129.4), p = .034], whereas serum total iron, free iron index, transferrin, UIBC and iron saturation were unchanged in CAD patients relative to control group. Among the indices of body iron only serum ferritin had significant association with the likelihood (OR of 1.004 (1.000-1.007), p = .04) and severity of CAD [χ²(3)= 7.99, p = .01], but the correlation was lessened in the presence of classical risk factors. Serum ferritin had also the highest and significant efficiency to predict CAD (AUC = 0.61, p = .020).Conclusions: Serum ferritin as a marker of intracellular iron has significant association with CAD; nevertheless, the correlation is not independent. Since iron deficiency is prevalent in elderly patients, iron hypothesis needs to expand to the both sides of iron deficiency and toxicity.

Transferrin plays a central role in coagulation balance by interacting with clotting factors

Coagulation balance is maintained through fine-tuned interactions among clotting factors, whose physiological concentrations vary substantially. In particular, the concentrations of coagulation proteases (pM to nM) are much lower than their natural inactivator antithrombin (AT, ~ 3 μM), suggesting the existence of other coordinators. In the current study, we found that transferrin (normal plasma concentration ~40 μM) interacts with fibrinogen, thrombin, factor XIIa (FXIIa), and AT with different affinity to maintain coagulation balance. Normally, transferrin is sequestered by binding with fibrinogen (normal plasma concentration ~10 μM) at a molar ratio of 4:1. In atherosclerosis, abnormally up-regulated transferrin interacts with and potentiates thrombin/FXIIa and blocks AT's inactivation effect on coagulation proteases by binding to AT, thus inducing hypercoagulability. In the mouse model, transferrin overexpression aggravated atherosclerosis, whereas transferrin inhibition via shRNA knockdown or treatment with anti-transferrin antibody or designed peptides interfering with transferrin-thrombin/FXIIa interactions alleviated atherosclerosis. Collectively, these findings identify that transferrin is an important clotting regulator and an adjuster in the maintenance of coagulation balance and modifies the coagulation cascade.

Association between serum ferritin and acute coronary heart disease: A population-based cohort study

BACKGROUND AND AIMS

Several studies aiming to determine the association between iron stores and coronary heart disease (CHD) have reported conflicting results. None of them has been performed in a Mediterranean region. Our aim is to assess the association between the level of serum ferritin and the incidence of CHD in a Mediterranean region.

METHODS

We performed a cohort study using a primary health care population database. Primary outcome was incidence of CHD. Subjects aged between 35 and 74 years with serum ferritin (SF) measurements at baseline (January 1, 2006 to December 31, 2008) were included. Cox regression models were used to compute hazard ratios (HRs) and 95%CIs for the associtation between SF and time until CHD outcome.

RESULTS

We include 242,084 subjects with SF levels at baseline. Participants were observed for a median of 8.4 years. During follow-up, 1106 incident cases of CHD were identified. Persons with elevated SF did not have an increased CHD risk at follow-up (adjusted hazard ratio = 0.99; 95%CI 0.94-1.05; p = 0.86 in men, and 0.95; 95%CI 0.81-1.13; p = 0.60 in women).

CONCLUSIONS

Our study, by far the largest, showed that high levels of SF do not confer an increased risk of CHD, and questions its role as a risk factor for this disease.

The Effects of Dietary Polyphenols on Circulating Cardiovascular Disease Biomarkers and Iron Status: A Systematic Review

The prevalence of cardiovascular disease (CVD) is rising worldwide, remaining the major cause of death in developed countries. Polyphenols have been shown to have cardioprotective properties; however, their impact on iron bioavailability and potential impact on other aspects of health is unclear. A systematic review was undertaken to evaluate the current status of the relationship between habitual polyphenol consumption, iron status, and circulating biomarkers of CVD. Following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2009 guidelines, searches were performed across 5 electronic databases (PubMed, Cochrane Library, Scopus, Web of Science, and CINAHL) to identify randomized controlled trials which investigated the effects of polyphenol consumption on inflammatory markers, serum lipid profile, and iron absorption and bioavailability. In total, 1174 records were identified, with only 7 studies meeting the inclusion criteria. The selected studies involved 133 participants and used a variety of foods and supplements, including olive oil and cherries, rich in polyphenols including hydroxytyrosol, quercetin, and resveratrol, as well as catechin enriched drinks. The duration of the studies ranged from between 56 and 145 days, with total polyphenolic content of the food items and supplements ranging from 45 to 1015 mg (per 100 g). Polyphenols did not appear to interfere with iron status, and most studies reported improvements in inflammatory markers and lipid profile. While these results are promising, the limited number of studies and considerable heterogeneity across the interventions support the need for more extensive trials assessing the relationship between polyphenol intake, iron bioavailability, and CVD risk.

Maternal cadmium exposure in the mouse leads to increased heart weight at birth and programs susceptibility to hypertension in adulthood

Cadmium (Cd) is a toxic heavy metal ubiquitous in the environment. Maternal exposure to Cd is associated with fetal growth restriction, trace element deficiencies, and congenital malformations. Cd exposure during adulthood is associated with cardiovascular disease (CVD); however, the effects of maternal Cd exposure on offspring cardiovascular development and disease are not well-understood. Utilizing a mouse model of maternal Cd exposure, we show that offspring born to Cd-exposed mothers have increased heart weights at birth and susceptibility to hypertension during adulthood. Despite inefficient maternal-fetal transfer of Cd, maternal Cd alters fetal levels of essential trace elements including a deficiency in iron, which is required for cardiovascular system development, oxygen homeostasis, and cellular metabolism. RNA-seq on newborn hearts identifies differentially expressed genes associated with maternal Cd exposure that are enriched for functions in CVD, hypertension, enlarged hearts, cellular energy, and hypoxic stress. We propose that a maternal Cd exposure-induced iron deficiency leads to altered cellular metabolic pathways and hypoxic conditions during fetal development; this stress may contribute to increased heart weight at birth and the programming of susceptibility to hypertension in adulthood. These studies will give insights into potential mechanisms through which maternal Cd exposure impacts cardiovascular development and disease.

Ferritin in Kidney and Vascular Related Diseases: Novel Roles for an Old Player

Iron is at the forefront of a number of pivotal biological processes due to its ability to readily accept and donate electrons. However, this property may also catalyze the generation of free radicals with ensuing cellular and tissue toxicity. Accordingly, throughout evolution numerous pathways and proteins have evolved to minimize the potential hazardous effects of iron cations and yet allow for readily available iron cations in a wide variety of fundamental metabolic processes. One of the extensively studied proteins in the context of systemic and cellular iron metabolisms is ferritin. While clinicians utilize serum ferritin to monitor body iron stores and inflammation, it is important to note that the vast majority of ferritin is located intracellularly. Intracellular ferritin is made of two different subunits (heavy and light chain) and plays an imperative role as a safe iron depot. In the past couple of decades our understanding of ferritin biology has remarkably improved. Additionally, a significant body of evidence has emerged describing the significance of the kidney in iron trafficking and homeostasis. Here, we briefly discuss some of the most important findings that relate to the role of iron and ferritin heavy chain in the context of kidney-related diseases and, in particular, vascular calcification, which is a frequent complication of chronic kidney disease.

Iron induces insulin resistance in cardiomyocytes via regulation of oxidative stress

Iron overload is associated with various pathological changes which contribute to heart failure. Here, we examined mechanisms via which iron alters cardiomyocyte insulin sensitivity. Treatment of primary adult and neonatal cardiomyocytes as well as H9c2 cells with iron decreased insulin sensitivity determined via Western blotting or immunofluorescent detection of Akt and p70S6K phosphorylation and glucose uptake. Using CellROX deep red or DCF-DA probes we also observed that iron increased generation of reactive oxygen species (ROS), and that pretreatment with the superoxide dismutase mimetic MnTBAP reduced ROS production and attenuated iron-induced insulin resistance. SKQ1 and allopurinol but not apocynin reduced iron-induced ROS suggesting mitochondria and xanthine oxidase contribute to cellular ROS in response to iron. Western blotting for LC3-I, LC3-II and P62 levels as well as immunofluorescent co-detection of autophagosomes with Cyto-ID and lysosomal cathepsin activity indicated that iron attenuated autophagic flux without altering total expression of Atg7 or beclin-1 and phosphorylation of mTORC1 and ULK1. This conclusion was reinforced via protein accumulation detected using Click-iT HPG labelling after iron treatment. The adiponectin receptor agonist AdipoRon increased autophagic flux and improved insulin sensitivity both alone and in the presence of iron. We created an autophagy-deficient cell model by overexpressing a dominant-negative Atg5 mutant in H9c2 cells and this confirmed that reduced autophagy flux correlated with less insulin sensitivity. In conclusion, our study showed that iron promoted a cascade of ROS production, reduced autophagy and insulin resistance in cardiomyocytes.

Ferritin levels throughout childhood and metabolic syndrome in adolescent stage

BACKGROUND AND AIM

Increased ferritin levels have been widely associated with cardiovascular risk in adults. Whether ferritin levels and their changes during childhood are related to metabolic syndrome (MetS) at adolescence is unknown. We aimed to evaluate these associations using levels of ferritin at 5, 10 and 16 years and their linear increases and patterns of sustained increased levels across childhood.

METHODS AND RESULTS

There were four samples evaluated according to non-missing values for study variables at each stage (5 years: 562; 10 years: 381; and 16 years: 567 children; non-missing values at any stage: 379). MetS risk was evaluated as a continuous Z score. Patterns of sustained increased ferritin (highest tertile) and slope of the change of ferritin per year across the follow-up were calculated. Ferritin levels in the highest versus lowest tertile at five and 16 years were significantly positively associated with MetS risk Z score at adolescence in boys and these associations were unaffected by adjustment for covariates. Having high, compared to low/moderate ferritin level at 2 or more time periods between 5 and 16 years was related to higher Mets Z-score in boys only [e.g. 5-10 years adjusted-beta (95 %CI):0.26 (0.05-0.48),P < 0.05]. In girls, ferritin Z score at 10 and 16 years was positively and independently associated with HOMA-IR Z score. In girls, the slope of ferritin per year in the highest tertile was positively associated with MetS risk Z-score [adjusted-beta (95 %CI):0.21 (0.05-0.38),P < 0.05].

CONCLUSIONS

Ferritin levels throughout childhood are positively related to cardiometabolic risk in adolescence, with associations varying by sex.

More evidence is needed. Iron, incident cognitive decline and dementia: a systematic review

Background

Our aim was to systematically review the relationship between iron and incident cognitive decline or dementia from midlife onwards.

Methods

Systematic review of eligible studies using Medline, Embase and PsycINFO^® for the period from 1 January 1986 to 2 December 2016 (CRD42016023800), where study populations had a mean age of over 50 years and were free of cognitive impairment or dementia at baseline. Two authors independently extracted data according to eligibility criteria and assessed study characteristics, quality and outcomes. Disagreement was resolved by discussion.

Results

A total of 1185 relevant records were identified with 12 full-text articles eligible for review. Six studies were excluded, leaving six texts to be included. Sample size ranged from 90 to 7173, with an average follow up of approximately 11.5 years. Baseline iron measures included brain iron (n = 2), iron-related biomarkers in blood and plasma (n = 2), and iron intake estimates from dietary records (n = 2). Outcomes were dementia incidence (n = 2) and longitudinal outcomes on neuropsychological tests (n = 4). Bias was evident across studies in one or more of the following: recruitment, iron exposure, outcome assessments, potential confounders, missing data or attrition.

Conclusions

Diversity across the small number of identified studies precludes conclusions regarding the role of iron in cognitive decline or dementia. Our review highlights substantial gaps in the evidence base and the need for more comprehensive, higher quality studies in this area.

More than a simple biomarker: the role of NGAL in cardiovascular and renal diseases

Neutrophil gelatinase-associated lipocalin (NGAL) is a small circulating protein that is highly modulated in a wide variety of pathological situations, making it a useful biomarker of various disease states. It is one of the best markers of acute kidney injury, as it is rapidly released after tubular damage. However, a growing body of evidence highlights an important role for NGAL beyond that of a biomarker of renal dysfunction. Indeed, numerous studies have demonstrated a role for NGAL in both cardiovascular and renal diseases. In the present review, we summarize current knowledge concerning the involvement of NGAL in cardiovascular and renal diseases and discuss the various mechanisms underlying its pathological implications.

Trace minerals intake: Risks and benefits for cardiovascular health

Minerals play a major role in regulating cardiovascular function. Imbalances in electrolyte minerals are frequent and potentially hazardous occurrences that may lead to the development of cardiovascular diseases (CVDs). Transition metals, such as iron, zinc, copper and selenium, play a major role in cell metabolism. However, there is controversy over the effects of dietary and supplemental intake of these metals on cardiovascular risk factors and events. Since their pro-oxidant or antioxidant functions can have different effects on cardiovascular health. While deficiency of these trace elements can cause cardiovascular dysfunction, several studies have also shown a positive association between metal serum levels and cardiovascular risk factors and events. Thus, a J- or U-shaped relationship between the transition minerals and cardiovascular events has been proposed. Given the existing controversies, large, well-designed, long-term, randomized clinical trials are required to better examine the effects of trace mineral intake on cardiovascular events and all-cause mortality in the general population. In this review, we discuss the role of dietary and/or supplemental iron, copper, zinc, and selenium on cardiovascular health. We will also clarify their clinical applications, benefits, and harms in CVDs prevention.

Diabetes and Anemia: International Diabetes Federation (IDF) - Southeast Asian Region (SEAR) position statement

Anemia is often associated with diabetes mellitus and is known to intensify the risk of developing diabetes-related microvascular and macrovascular complications. There is paucity in understanding of co-existence of these conditions, especially in Southeast Asian countries. Iron and/or erythropoietin deficiencies are the major causes of anemia in diabetes, and diabetic kidney disease plays a key role. Patients with diabetes need to be screened for anemia along with other risk factors and anemia should be corrected appropriately to improve overall clinical outcomes. This position statement aims to provide a comprehensive overview and an algorithm for appropriate management of anemia in patients with diabetes.

Lower systolic blood pressure at age 7 y in low-birth-weight children who received iron supplements in infancy: results from a randomized controlled trial

Background: Low birth weight (LBW) (≤2500 g) is associated with iron deficiency in infancy and high blood pressure (BP) later in life.Objective: We investigated the effect of iron supplementation that was given to LBW infants on midchildhood BP.Design: The study was a randomized, double-blind, controlled trial that included 285 marginally LBW (2000-2500-g) infants at 2 Swedish centers between May 2004 and November 2007. The infants were randomly assigned to receive a placebo or 1 or 2 mg Fe · kg^-1 · d^-1 from 6 wk to 6 mo of age. In secondary analyses at the age of 7 y, systolic blood pressure (SBP), diastolic blood pressure (DBP), and the prevalence of children with BP within the hypertensive range (>90th percentile) were compared between the groups.Results: BP was analyzed via intention to treat in 189 children (66%). The mean ± SD SBP was 103 ± 8.1, 101 ± 7.5, and 101 ± 7.8 mm Hg in children who had received the placebo (n = 70), 1 mg Fe · kg^-1 · d^-1 (n = 54), or 2 mg Fe · kg^-1 · d^-1 (n = 65), respectively. When the iron-supplemented groups were combined in covariate-adjusted analyses, the mean SBP in LBW children who had received iron supplementation in infancy was 2.2 mm Hg (95% CI: 0.3, 4.2 mm Hg) lower than in those who were unsupplemented (P = 0.026). Multivariate logistic regression showed that iron supplementation in infancy reduced the odds of having an SBP within the hypertensive range at 7 y of age (OR: 0.32; 95% CI: 0.11, 0.96). For DBP, there were no significant differences between the intervention groups.Conclusions: LBW children who receive iron supplementation (1 or 2 mg Fe · kg^-1 · d^-1) in infancy have lower SBP at 7 y. This (to our knowledge) novel observation suggests that the increased risk of hypertension that is observed in children and adults who are born small might be reduced with early micronutrient interventions. This trial was registered at clinicaltrials.gov as NCT00558454.

The role of micronutrients in the response to ambient air pollutants: Potential mechanisms and suggestions for research design

People living in regions of low socioeconomic status are thought to be prone to higher exposures to environmental pollutants, poor nutrition, and numerous preventable diseases and infections. Poverty correlates with pollution and malnutrition; however, limited studies examined their interrelationship. The well-studied, deleterious health effects attributed to environmental pollutants and poor nutrition may act in combination with produce more severe adverse health outcomes than any one factor alone. Deficiencies in specific nutrients render the body more susceptible to injury which may influence the pathways that serve as the mechanistic responses to ambient air pollutants. This review (1) explores specific micronutrients that are of global concern, (2) explains how these nutrients may impact the body's response to ambient air pollution, and (3) provides guidance on designing animal models of nutritional deficiency. It is likely that those individuals who reside in regions of high ambient air pollution are similarly malnourished. Therefore, it is important that research identifies specific nutrients of concern and their impact in identified regions of high ambient air pollution.

Hydroxytyrosol supplementation increases vitamin C levels in vivo. A human volunteer trial

Hydroxytyrosol (HT) is a main phenolic component of olive oil. In this study, we investigated the safety and effects produced by HT purified (99.5%) from olive mill waste. HT was administered at a daily dosage of 45 mg for 8 weeks to volunteers with mild hyperlipidemia (n=14). We measured markers of cardiovascular disease risk, enzyme markers of several clinical conditions, hematology, antioxidant parameters, vitamins and minerals at baseline (T0), 4 weeks (T4) and 8 weeks (T8). The values obtained at T4 and T8 were compared with baseline. We found that the HT dose administered was safe and mostly did not influence markers of cardiovascular disease, blood lipids, inflammatory markers, liver or kidney functions and the electrolyte balance. Serum iron levels remained constant but a significant (P<0.05) decrease in ferritin at T4 and T8 was found. Serum folate and red blood cell folate levels were also reduced at T4 and T8. Finally, vitamin C increased by two-fold at T4 and T8 compared with levels at baseline. These results indicate a physiologically relevant antioxidant function for HT through increasing endogenous vitamin C levels.

Anemia management in cancer patients with chronic kidney disease

Anemia is a common complication of cancer and chronic kidney disease (CKD) associated with decreased physical performance as well as poor prognosis for life expectancy. Renal and cancer-induced anemia share common features regarding pathogenesis and therapeutic strategies. It is typically treated with iron substitution, erythropoiesis-stimulating agents (ESA) and in refractory cases with red blood cell transfusions. However, studies of the past few years unveiled numerous setbacks in the use of ESAs. These included a higher risk of cerebrovascular events and increased mortality without the improvement of cardiovascular outcomes in patients with CKD. Moreover, particularly negative results were observed in patients with previous cancer history under ESA therapy. These unfavorable findings have forced the clinicians to reevaluate the management of renal anemia. This led to decrease of ESA usage, while iron substitution and alternative therapeutic options gained more significance. Iron supplementation is also accompanied with certain risks ranging from gastrointestinal complications to severe allergic reactions and increased rate of infections. Furthermore, the evaluation of the long-term safety of excessive iron therapy is still lacking, especially in CKD patients with cancer. In the absence of these clinical studies, this review aims to summarize the currently available therapeutic strategies in anemia management of CKD patients with concomitant cancer.

Serum ferritin and risk for new-onset heart failure and cardiovascular events in the community

AIMS

Heart failure (HF) is a common manifestation of patients with primary and secondary causes of iron overload, whereas in patients with established HF iron deficiency impairs outcome. Whether iron stores, either depleted or in overload, amplify the risk for new-onset HF among healthy individuals is unknown. The present study aimed to assess whether markers of iron status or the iron-regulatory hormone hepcidin are associated with new-onset HF or cardiovascular (CV) events in the general population.

METHODS AND RESULTS

In 6386 subjects from the Prevention of REnal and Vascular ENd-stage Disease (PREVEND) trial, a prospective, community-based, cohort study, markers of iron status and the iron-regulatory hormone hepcidin were measured. Mean age was 53.1 ± 12.0 years, and 50.7% of the cohort was female. During a median follow-up of 8.3 (interquartile range 7.8-8.9) years, 199 subjects (3.1%) were newly diagnosed with HF, 456 (7.1%) experienced a CV event, and 356 (5.6%) died from all causes. A higher annual HF incidence per ferritin quartile was observed in women (P < 0.001), but not in men (P for interaction 0.032). Multivariable analyses demonstrated ferritin levels to remain independently predictive for new-onset HF in women only (P = 0.024). This association persisted within strata defined by markers of the metabolic syndrome, markers of inflammation, or other markers of iron homeostasis, including hepcidin. No association between ferritin or hepcidin and incident CV events or all-cause mortality was observed in either sex.

CONCLUSIONS

Increased serum ferritin levels independently amplify the risk for new-onset HF in women in the community.

Soluble transferrin receptor levels are positively associated with insulin resistance but not with the metabolic syndrome or its individual components

The metabolic syndrome (MetS) is known to be associated with elevated serum ferritin levels. The possible association with other Fe markers has been less well studied. We aimed to investigate the cross-sectional association of soluble transferrin receptor (sTfR) and ferritin levels with the MetS components, insulin resistance and glycosylated Hb (HbA1C). The sample consisted of 725 adults, aged 19-93 years (284 men, 151 premenopausal and 290 postmenopausal women), from the Croatian island of Vis. Serum sTfR and ferritin levels were measured by immunoturbidimetry and electrochemiluminescence assays, respectively. The MetS was defined using modified international consensus criteria. Logistic and linear regression analyses were conducted to investigate the associations adjusting for age, fibrinogen, smoking status, alcohol consumption and BMI. Prevalence of the MetS was 48·7 %. Standardised values of ferritin were positively associated with all of the MetS components (except high blood pressure and waist circumference) in men (P0·05). sTfR levels could be spuriously elevated in subjects with insulin resistance and without association with the MetS or its components. We conclude that different markers of Fe metabolism are not consistently associated with cardiometabolic risk.

EDTA Chelation Therapy to Reduce Cardiovascular Events in Persons with Diabetes

The Trial to Assess Chelation Therapy (TACT) was a randomized double-blind placebo-controlled trial enrolling patients age ≥50 years with prior myocardial infarction. TACT used a 2 × 2 factorial design to study ethylene diamine tetraacetic acid (EDTA) chelation and high-dose vitamin supplementation. Chelation provided a modest but significant reduction in cardiovascular endpoints. The benefit was stronger and significant among participants with diabetes but absent in those without diabetes. Mechanisms by which chelation might reduce cardiovascular risk in persons with diabetes include the effects of EDTA chelation on transition and toxic metals. Transition metals, particularly copper and iron, play important roles in oxidative stress pathways. Toxic metals, in particular cadmium and lead, are toxic for the cardiovascular system. This review discusses the epidemiologic evidence and animal and human studies supporting the role of these metals in the development of diabetes and ischemic heart disease and potential ways by which EDTA chelation could confer cardiovascular benefit.

Vascular Damage in Patients with Nonalcoholic Fatty Liver Disease: Possible Role of Iron and Ferritin

Non Alcoholic Fatty Liver Disease (NAFLD) is the most common chronic liver disease in Western countries. Recent data indicated that NAFLD is a risk factor by itself contributing to the development of cardiovascular disease independently of classical known risk factors. Hyperferritinemia and mild increased iron stores are frequently observed in patients with NAFLD and several mechanisms have been proposed to explain the role of iron, through oxidative stress and interaction with insulin metabolism, in the development of vascular damage. Moreover, iron depletion has been shown to decrease atherogenesis in experimental models and in humans. This review presents the recent evidence on epidemiology, pathogenesis, and the possible explanation of the role of iron and ferritin in the development of cardiovascular damage in patients with NAFLD, and discusses the possible interplay between metabolic disorders associated with NAFLD and iron in the development of cardiovascular disease.

Iron metabolism and regulation by neutrophil gelatinase-associated lipocalin in cardiomyopathy

Neutrophil gelatinase-associated lipocalin (NGAL) has recently become established as an important contributor to the pathophysiology of cardiovascular disease. Accordingly, it is now viewed as an attractive candidate as a biomarker for various disease states, and in particular has recently become regarded as one of the best diagnostic biomarkers available for acute kidney injury. Nevertheless, the precise physiological effects of NGAL on the heart and the significance of their alterations during the development of heart failure are only now beginning to be characterized. Furthermore, the mechanisms via which NGAL mediates its effects are unclear because there is no conventional receptor signalling pathway. Instead, previous work suggests that regulation of iron metabolism could represent an important mechanism of NGAL action, with wide-ranging consequences spanning metabolic and cardiovascular diseases to host defence against bacterial infection. In the present review, we summarize rapidly emerging evidence for the role of NGAL in regulating heart failure. In particular, we focus on iron transport as a mechanism of NGAL action and discuss this in the context of the existing strong associations between iron overload and iron deficiency with cardiomyopathy.