A hypothesis: Potential contributions of metals to the pathogenesis of pulmonary artery hypertension

Pulmonary artery hypertension (PAH) is characterized by vasoconstriction and vascular remodeling resulting in both increased pulmonary vascular resistance (PVR) and pulmonary artery pressure (PAP). The chronic and high-pressure stress experienced by endothelial cells can give rise to inflammation, oxidative stress, and infiltration by immune cells. However, there is no clearly defined mechanism for PAH and available treatment options only provide limited symptomatic relief. Due to the far-reaching effects of metal exposures, the interaction between metals and the pulmonary vasculature is of particular interest. This review will briefly introduce the pathophysiology of PAH and then focus on the potential roles of metals, including essential and non-essential metals in the pathogenic process in the pulmonary arteries and right heart, which may be linked to PAH. Based on available data from human studies of occupational or environmental metal exposure, including lead, antimony, iron, and copper, the hypothesis of metals contributing to the pathogenesis of PAH is proposed as potential risk factors and underlying mechanisms for PAH. We propose that metals may initiate or exacerbate the pathogenesis of PAH, by providing potential mechanism by which metals interact with hypoxia-inducible factor and tumor suppressor p53 to modulate their downstream cellular proliferation pathways. These need further investigation. Additionally, we present future research directions on roles of metals in PAH.

Perfluoroalkyl substances (PFAS) and lead (Pb) as "cardiovascular disruptors" in 9-11-year-old children living in Syracuse, New York, United States

OBJECTIVE

Per- and polyfluoro-alkyl substances (PFAS) and lead (Pb) are ubiquitous environmental toxicants with apparent impact on cardiovascular disease (CVD) risk. As one possible mechanism for this increased risk, we have previously demonstrated an association between Pb exposure and heightened cardiovascular reactivity to acute psychological stress, a CVD risk factor. The present study expands this approach and considers both PFAS and Pb exposures (and the possible interaction).

METHODS

We assessed 14 serum PFAS and whole blood Pb concentrations in a sample of 9-11 year-old children (N = 291; 43.2% White, 56.8% Black; 53.5% female). We measured cardiovascular functioning at rest and during psychological stress as well as multiple indicators of subclinical CVD including resting blood pressure (BP), carotid-femoral pulse wave velocity (cfPWV), carotid intima-media thickness (cIMT), and left ventricular mass (LVM). Data analysis included general linear modeling as well as a non-parametric approach to study metal mixtures, specifically Bayesian Kernel Machine Regression (BKMR).

RESULTS

Significant interactions between different PFAS and with Pb suggest the importance of considering toxicant mixtures when assessing potential disruption of the cardiovascular system. The pattern of findings suggests that greater "vascular reactivity" (elevated BP and vascular resistance during acute psychological stress) was associated with higher concentrations of perfluorononanoic acid (PFNA), perfluorohexane sulfonate (PFHxS), and Pb, but only when perfluorooctanoic acid (PFOA) was concurrently elevated. With respect to subclinical outcomes, increasing perfluorodecanoic acid (PFDA) was associated with greater cIMT (β = 0.21, p = 0.010).

CONCLUSION

To our knowledge this is the first study to consider how PFAS exposures might affect cardiovascular functioning and subclinical disease. Although a complex pattern of associations emerged, it does appear that PFAS and Pb can be classified as "cardiovascular disruptors" in children. Further research is needed to replicate these novel findings and determine whether these disruptions produce future cardiovascular disease.

Potential Roles of Metals in the Pathogenesis of Pulmonary and Systemic Hypertension

Pulmonary and systemic hypertension (PH, SH) are characterized by vasoconstriction and vascular remodeling resulting in increased vascular resistance and pulmonary/aortic artery pressures. The chronic stress leads to inflammation, oxidative stress, and infiltration by immune cells. Roles of metals in these diseases, particularly PH are largely unknown. This review first discusses the pathophysiology of PH including vascular oxidative stress, inflammation, and remodeling in PH; mitochondrial dysfunction and metabolic changes in PH; ion channel and its alterations in the pathogenesis of PH as well as PH-associated right ventricular (RV) remodeling and dysfunctions. This review then summarizes metal general features and essentiality for the cardiovascular system and effects of metals on systemic blood pressure. Lastly, this review explores non-essential and essential metals and potential roles of their dyshomeostasis in PH and RV dysfunction. Although it remains early to conclude the role of metals in the pathogenesis of PH, emerging direct and indirect evidence implicates the possible contributions of metal-mediated toxicities in the development of PH. Future research should focus on comprehensive clinical metallomics study in PH patients; mechanistic evaluations to elucidate roles of various metals in PH animal models; and novel therapy clinical trials targeting metals. These important discoveries will significantly advance our understandings of this rare yet fatal disease, PH.

Investigation of the levels of essential and non-essential metals in women with and without abortion history: A study based on the Persian population of the Shahrekord cohort

Spontaneous abortion is a serious threat to the mothers' physical and mental well-being. The cause of spontaneous abortion is multifactorial disease. Prenatal non-essential metal exposure, particularly heavy metals, has been suggested to be associated with adverse pregnancy and birth outcomes. The purpose of this study was to investigate the relationship between the concentration of essential and non-essential metals including Pb, As, Zn, and Se and the risk of spontaneous abortion. In this case-control study the levels of Pb, As, Zn, and Se in the whole blood of 60 women with spontaneous abortion (case group) and also 60 women without spontaneous abortion (control group) were measured by atomic absorption spectrophotometry. Results revealed statistically significant reductions (P < 0.001) in whole blood levels of Zn and Se as well as the levels of As and Pb had a substantial elevation (P < 0.001) in cases compared to controls. According to the findings, repeated spontaneous abortion may be influenced by increasing whole blood levels of heavy metals such as As (OR = 17.53, P = 0.001) and Pb (OR = 15.58, P = 0.001) as well as decreasing levels of vital micronutrients Zn (OR = 0.20, P = 0.001) and Se (OR = 0.14, P = 0.001). The results of this study support the idea that limiting intake of non-essential metals during pregnancy can decrease the risk of spontaneous abortion. Overall, the information presented is expected to help plan future fundamental and applied investigations on the spontaneous abortion.

Association Between Essential and Non-essential Metals, Body Composition, and Metabolic Syndrome in Adults

Growing evidence indicates that metal exposure is associated with metabolic syndrome (MetS); however, mixed results have been reported. The aim of this study was to clarify associations of exposure to essential and non-essential metals with body composition and risks of obesity and MetS. Anthropometry and blood biochemistry of metabolic parameters were obtained from 150 middle-aged Taiwanese adults. Plasma metals were assessed using inductively coupled plasma mass spectrometry, and body compositions were measured by a bioelectrical impedance analysis (BIA). The essential metals of copper (Cu), manganese (Mn), and chromium (Cr) were positively correlated with the body fat mass but inversely correlated with the skeletal muscle mass (all p < 0.05). An adjusted logistic regression showed that Mn [odds ratio (OR) = 1.624 (95% confidence interval 1.072, 2.462), p = 0.02] and, to a lesser extent, Cu [OR = 1.501 (0.985, 2.292), p = 0.059] predicted abdominal obesity, while plasma Cu [OR = 2.211 (1.146, 4.266), p = 0.02] and zinc (Zn) [OR = 2.228 (1.048, 4.736) p = 0.04] predicted MetS. Significant correlations between dyslipidemia and lithium [OR = 1.716 (1.080, 2.726)], Cu [OR = 2.210 (1.415, 3.454)], Mn [OR = 2.200 (1.320, 3.666)], molybdenum [OR = 1.853 (1.160, 2.958)], and Zn [OR = 1.993 (1.186, 3.349)], and between boron [OR = 2.583 (1.137, 5.868)] and hyperglycemia were observed (all p < 0.05). Exposure to essential metals may affect the body composition and metabolic profiles, exacerbating the risk of MetS.

Plasma level of antimony correlates with pulmonary arterial hypertension severity

It is unknown if environmental antimony exposure influences pulmonary arterial hypertension (PAH) and right ventricular function. We performed a pilot study to evaluate antimony levels in 20 PAH patients and 10 controls. Also, we explored the correlation of antimony level with PAH prognostic hemodynamic markers. Antimony blood and plasma levels were significantly higher in PAH patients when compared to controls [blood: PAH mean ± SD (95%CI) 1.3 ± 0.6 (1.0-1.5) ng/ml vs. control mean ± SD (95%) 0.7 ± 0.5 (0.4-1.0) ng/ml, p = 0.017] [plasma: PH mean ± SD (95%CI) 2.6 ± 1 (2.2-3.1) ng/ml vs. control mean ± SD (95%CI) 1.5 ± 0.8 (1.0-2.0) ng/ml, p = 0.004]. Also, antimony blood and plasma levels were significantly higher in idiopathic-PAH patients and non-idiopathic PAH when compared to controls. There was a trend for higher blood and plasma antimony levels in idiopathic PAH [blood1.6 ± 0.6 (1.1-2.1) ng/ml and plasma 3.1 ± 1.2 (2.2-4.1) ng/ml] when compared to non-idiopathic PAH [blood 1.1 ± 0.6(0.8-1.4) ng/ml and plasma 2.5 ± 0.9(2-2.9) ng/ml], but it did not reach statistical significance. There was a significant correlation between plasma antimony level and all the prognostic hemodynamic parameters of PAH including mRAP (r = 0.47, p = 0.036), CO (r = -0.50, p = 0.026), CI (r = -0.54, p = 0.014), PVR (r = 0.52, p = 0.019), and SvO2 (r = -0.54, p = 0.016).

Health risk assessment of metals in mud crab (Scylla serrata) from the East Java Estuaries of Indonesia

Metals accumulating in mud crab from Indonesia's East Java estuaries have been assessed for potential health effects. Mud crabs from the Solo River estuary (JS) had the highest levels of all metals tested when compared to mud crabs from the Brantas River estuary (MS) and the Banyuwangi coastal area (BS). Metal accumulation in mud crabs occurred in the following order: Zn > Cu > Cr > Pb > Cd > Hg. The estimated weekly intake values for all metals from all stations were less than the provisional tolerable weekly intake requirement. Similarly, all metal target hazard quotient values from all stations were less than one, suggesting that all metals were within the allowable intake limit. The target cancer risk values for Cd and Cr, on the other hand, were somewhat higher than 10^-4, indicating that they were dangerous for human ingestion and possibly linked to a risk associated with carcinogenic agent exposure over a lifetime.

Metal concentrations and potential health risk in clam (Meretrix lyrata Sowerby 1851) tissues from East Java Coast, Indonesia

The presence of Hg, Cu, Cr, Cd, Pb, and Zn in clam (Meretrix lyrata) from the East Java Coast (EJC), Indonesia, is reported in this study. Metal levels in clam whole tissues were Zn > Cu > Cr > Pb > Cd > Hg. Cr, Cd, and Pb levels in clam tissue surpassed the tolerated limit for eating and the provisional acceptable weekly intake (PTWI) at numerous places along the EJC. The target hazard quotients (THQs) for Cr, Cd, and Pb were greater than one in several locations, indicating that these metals could be harmful to consumers (particularly non-carcinogenic impacts). Eating clams from this area may be detrimental to human health. Furthermore, target cancer risk (TCR) values for Cr and Cd were greater than 10^-4 in several locations, implying that Cr and Cd could cause cancer in people over the course of a lifetime of exposure.

Combined effects of heavy metals (Cd, As, and Pb): Comparative study using conceptual models and the antioxidant responses in the brackish water flea

The combined effect of toxic inducers has emerged as a challenging topic, particularly due to their inconsistent impacts on the environment. Using toxic unit (TU) based on LC₅₀ value, we investigated the 48 h acute toxicities of the following combinations: Cd + As, Cd + Pb, As + Pb, and Cd + As + Pb, and binary and ternary combined effects were interpreted using concentration addition (CA) and independent action (IA) model. The molecular effects of these combinations were further examined on the basis of gene expression (four GST and two SOD isoforms) and antioxidant enzymes activity (SOD and GST). The CA-predicted LC₅₀ was similar to the observed results, indicating that the CA model is more applicable for evaluating the combined effects of the metal mixtures. Synergistic effects (ΣTU_LC50 < 0.8) were observed for the mixtures As + Pb and Cd + Pb, while additive effects (0.8 < ΣTU_LC50 < 1.2) were observed for the mixtures Cd + As + Pb and Cd + As. No antagonistic effects were observed in this study. Molecular biomarkers for oxidative stress caused by metals, as well as traditional endpoints such as lethality, have shown a clear response in assessing the toxicity of binary and ternary mixtures. This study opens up a new avenue for the use of biomarkers to assess the combined effects of metals in aquatic environments.

Life and death of Trypanosoma cruzi in presence of metals

Trypanosoma cruzi has many molecules that need metallic elements to work, allowing cell invasion and the establishment of infection, causing Chagas disease. Nonetheless, knowledge regarding how the parasites address metals and maintain homeostasis is lacking. To study this relationship, zinc, cadmium and mercury were chosen. Epimastigote, trypomastigote and intracellular forms of T. cruzi were incubated with these metals for different times and at different concentrations. In general, epimastigotes were the most sensitive and trypomastigotes the most resistant to metals. ZnCl₂ induced low toxic effects to all parasite forms. Although the parasites were very sensitive to the toxic effects of CdCl₂ and HgCl₂, pretreatment with ZnCl₂ decreased the death rate. The trypomastigotes pretreated with CdCl₂ were unable to infect the host cells, and the treated intracellular forms were damaged after 2 h of incubation, when the toxic effects were poorly reverted. New insights on metal toxicity mechanisms are provided, helping to understand how metallic ions influence the parasite's biochemical and physiological processes.

Levels of essential and non-essential metals in ginger (Zingiber officinale) cultivated in Ethiopia

BACKGROUND

Ginger (Zingiber officinale Roscoe) is a common condiment for various foods and beverages and widely used worldwide as a spice. Its extracts are used extensively in the food, beverage, and confectionary industries in the production of products such as marmalade, pickles, chutney, ginger beer, ginger wine, liquors, biscuits, and other bakery products. In Ethiopia, it is among the important spices used in every kitchen to flavor stew, tea, bread and local alcoholic drinks. It is also chiefly used medicinally for indigestion, stomachache, malaria, fevers, common cold, and motion sickness. The literature survey revealed that there is no study conducted on the determination of metals in ginger cultivated in Ethiopia. Hence it is worthwhile to determine the levels of essential and non-essential metals in ginger cultivated in Ethiopia.

METHODS

The levels of essential (Ca, Mg, Fe, Zn, Cu, Co, Cr, Mn, and Ni) and non-essential (Cd and Pb) metals in ginger (Zingiber officinale Roscoe) cultivated in four different regions of Ethiopia and the soil where it was grown were determined by flame atomic absorption spectrometry. 0.5 g of oven dried ginger and soil samples were digested using 3 mL of HNO3 and 1 mL of HClO4 at 210°C for 3 h and a mixture of 6 mL aqua-regia and 1.5 mL H2O2 at 270°C for 3 h, respectively.

RESULTS

The mean metal concentration (μg/g dry weight basis) ranged in the ginger and soil samples, respectively, were: Ca (2000-2540, 1770-3580), Mg (2700-4090, 1460-2440), Fe (41.8-89.0, 21700-46900), Zn (38.5-55.2, 255-412), Cu (1.1-4.8, 3.80-33.9), Co (2.0-7.6, 48.5-159), Cr (6.0-10.8, 110-163), Mn (184-401, 1760-6470), Ni (5.6-8.4, 14.1-79.3) and Cd (0.38-0.97, 0.24-1.1). The toxic metal Pb was not detected in both the ginger and soil samples.

CONCLUSION

There was good correlation between some metals in ginger and soil samples while poor correlation between other metals (Fe, Ni, Cu). This study revealed that Ethiopian gingers are good source of essential metals and free from toxic metal Pb while containing negligible amount of Cd.