Alterations in serum selenium levels and their relation to troponin I in acute myocardial infarction

Selenium as a Modulator of Redox Reactions in the Prevention and Treatment of Cardiovascular Diseases

Cardiovascular diseases stand as the predominant global cause of mortality, exerting a profound impact on both life expectancy and its quality. Given their immense public health burden, extensive efforts have been dedicated to comprehending the underlying mechanisms and developing strategies for prevention and treatment. Selenium, a crucial participant in redox reactions, emerges as a notable factor in maintaining myocardial cell homeostasis and influencing the progression of cardiovascular disorders. Some disorders, such as Keshan disease, are directly linked with its environmental deficiency. Nevertheless, the precise extent of its impact on the cardiovascular system remains unclear, marked by contradictory findings in the existing literature. High selenium levels have been associated with an increased risk of developing hypertension, while lower concentrations have been linked to heart failure and atrial fibrillation. Although some trials have shown its potential effectiveness in specific groups of patients, large cohort supplementation attempts have generally yielded unsatisfactory outcomes. Consequently, there persists a significant need for further research aimed at delineating specific patient cohorts and groups of diseases that would benefit from selenium supplementation.

Selenoprotein P in Myocardial Infarction With Cardiogenic Shock

BACKGROUND

Reperfusion strategies in acute myocardial infarction (AMI) may result in ischemia reperfusion injury characterized by increased oxidative stress, inflammation, and ultimately death of myocardial tissue which may be of particular importance in infarct-related cardiogenic shock (CS). Many anti-oxidative and immune regulatory processes depend on selenium which in large proportions is bound to circulating selenoprotein P (SelP). Individual SelP patterns may therefore be associated with inflammatory response and possibly mortality in patients with CS post AMI.

METHODS

In the randomized Intra-Aortic Balloon Pump in cardiogenic Shock II (IABP-SHOCK II)-trial, 600 patients with CS complicating AMI were assigned to therapy with or without IABP. In a predefined biomarker substudy of 147 patients, we analyzed SelP levels 1 and 3 days following randomization. Samples were compared with healthy controls and associations with the unspecific inflammatory marker C-reactive protein (CRP) were analyzed.

RESULTS

Compared with controls SelP levels in patients with infarct-related CS were markedly higher (2.7-fold at day 1 and 5.7-fold at day 3 following AMI, all P < 0.001). Thirty-day mortality was significantly higher in patients with SelP levels above the 75th percentile at day 3 following AMI (26% vs. 46%, P = 0.045). SelP was significantly proportionally correlated with CRP 1 (R = 0.762, P < 0.0001) and 3 days (R = 0.777 P < 0.0001) following AMI.

CONCLUSION

SelP levels are significantly increased post AMI with CS. Higher SelP levels are associated with increased CRP levels indicative for inflammatory processes. Future studies should focus on the characterization of SelP profiles following AMI and the identification of pathomechanisms affected by SelP.

Nutraceuticals in Chronic Coronary Syndromes: Preclinical Data and Translational Experiences

Non-pharmacological treatments have always been considered important in the management of Chronic Coronary Syndromes. Nutraceuticals ("Nutrition" + "Pharmaceutical") could fall both under the definition of non-pharmacological treatment and pharmacological one or, probably more correctly, in the middle of these two kinds of therapies. However, the word "nutraceuticals" never appears in the latest guidelines on this issue. This is probably determined by the fact that evidences on this topic are scarce and most of the published articles are based on preclinical data while translational experiences are available only for some molecules. In this review we will focus on nutraceutical strategies that act on the ischemic myocardium itself and not only on the cardiovascular risk factors. As demonstrated by the important number of papers published in recent years, this is an evolving topic and evaluated substances principally act on two mechanisms (cardiac energetics and ischemia-reperfusion damage) that will be also reviewed.

Study of rs1137101 polymorphism of leptin receptor gene with serum levels of selenium and copper in the patients of non-ST-segment elevation myocardial infarction (NSTEMI) in an Iranian population

OBJECTIVE

NSTEMI is a type of myocardial infarction (MI) causing partial but progressive occlusion of cardiac coronary vessels. The aim of this study was to investigate rs1137101 polymorphism of soluble leptin receptor (sLEPR) as well as circulatory selenium and copper levels in NSTEMI patients and their usefulness in analyzing susceptibility to NSTEMI.

METHODS

We collected sera and whole blood of 80 NSTEMI patients and 80 healthy individuals using cTnI levels plus electrocardiography as the "gold standard". Polymorphism analysis was done after DNA extraction by high-resolution melt PCR, selenium and copper levels by atomic absorption spectrophotometry, and sLEPR by ELISA.

RESULTS AND DISCUTION

There was Hardy-Weinberg (HWE) equilibrium for both patient and control loci (χ2 = 0.368434509 and 0.341447368, respectively). The frequencies of A/A, A/G, and G/G genotypes were 18 (22%), 37 (46%), and 25 (31%) for patients, and 30 (38%), 36 (45%), and 14 (18%) for healthy controls, respectively. The frequencies of A and G alleles were 73 (46%) and 87 (54%) for patients and 96 (60%) and 64 (40%) for control groups. There was correlation between allele G and sLEPR level and Body Mass Index (BMI). Selenium levels were lower in patient group than control group (66.307 ± 11.013 against 87.488 ± 11.839 μg/L; p < 0.001) but copper concentrations were higher (1.8105 ± 0.358 against 1.366 ± 0.454 mg/L; p < 0.001). sLEPR levels were also higher in patient than control group (30.568 ± 3.290 against 23.740 ± 5.457 ng/dL; p < .001). Low selenium and high copper concentration had positive diagnostic value for disease.

CONCLUSION

We find for the first time that there is a significant association between rs1137101 polymorphism and susceptibility to NSTEMI. There is also statistically meaningful association between decrease in serum selenium and increase in serum copper levels with susceptibility to NSTEMI.

Age-dependent changes in essential elements and oxidative stress biomarkers in blood of red deer and vulnerability to nutritional deficiencies

Changes in the concentration of circulating essential elements in animals over life may be indicative of periods of vulnerability to deficiencies and associated diseases. Here we studied age-related variations in essential elements (Se, Cu, Zn and Mn) and some selected oxidative stress biomarkers (GPx, SOD, vitamin A and vitamin E) in blood of an Iberian red deer (Cervus elaphus hispanicus) population living in semicaptive conditions. Animals during their first year of life showed to be especially vulnerable to suffer Se- and Cu-related diseases and disorders. Older female deer had lower blood levels of Zn and Mn, which was accompanied by a lower blood SOD activity. On the contrary, GPx blood activity was elevated in older deer, which may help to compensate the reduction of other antioxidants with during aging. Age-related changes in GPx and SOD and their positive relationships with the essential elements suggest that the observed nutritional deficiencies at certain age stages may have a detrimental effect on the antioxidant system, increasing the risk of oxidative stress. Thus, the biomarkers used in the present study may be important tools for the subclinical diagnosis of nutritional disorders and diseases related to the generation of oxidative stress in both domestic and wild ungulates.

Deficient zinc levels and myocardial infarction : association between deficient zinc levels and myocardial infarction: a meta-analysis

The purpose of this study is to clarify the association between Zn levels and myocardial infarction (MI) using a meta-analysis approach. We searched articles in the PubMed, OVID, and ScienceDirect published as of November 2014. Thirteen eligible articles with 2886 subjects from 41 case-control studies were identified. Overall, pooled analysis indicated that subjects with MI had lower Zn levels than healthy controls (standardized mean difference (SMD) = -1.848, 95 % confidence interval (CI) = [-2.365, -1.331]). Further subgroup analysis found that subjects with MI had lower Zn levels than healthy controls in serum (SMD = -1.764, 95 % CI = [-2.417, -1.112]) and hair (SMD = -3.326, 95 % CI = [-4.616, -2.036]), but not in toenail (SMD = -0.396, 95 % CI = [-1.114, 0.322]). The subgroup analysis stratified by type of Zn measurement found a similar pattern in inductively coupled plasma-atomic absorption spectrometry (ICP-AAS) (SMD = -2.442, 95 % CI = [-3.092, -1.753]), but not in neutron activation analysis (NAA) (SMD = -0.449, 95 % CI = [-1.127, 0.230]). Lower Zn levels in MI patients were found both in male (SMD = -3.350, 95 % CI = [-4.531, -2.169]) and female (SMD = -2.681, 95 % CI = [-3.440, -1.922]). And the difference of Zn levels according to MI in Asia (SMD = -2.555, 95 % CI = [-3.267, -1.844]) was greater to that among the population in Europe (SMD = -0.745, 95 % CI = [-1.386, -0.104]), but no difference was found in Oceania (SMD = -0.255, 95 % CI = [-0.600, 0.089]). In conclusion, this meta-analysis indicates that there is a significant association between Zn deficiency and MI. We suggest that a community-based, long-term observation in a cohort design should be performed to obtain better understanding of causal relationships between Zn and MI, through measuring hair Zn at baseline to investigate whether the highest zinc category versus lowest was associated with MI risk.

Selenium and its supplementation in cardiovascular disease--what do we know?

The trace element selenium is of high importance for many of the body’s regulatory and metabolic functions. Balanced selenium levels are essential, whereas dysregulation can cause harm. A rapidly increasing number of studies characterizes the wide range of selenium dependent functions in the human body and elucidates the complex and multiple physiological and pathophysiological interactions of selenium and selenoproteins. For the majority of selenium dependent enzymes, several biological functions have already been identified, like regulation of the inflammatory response, antioxidant properties and the proliferation/differentiation of immune cells. Although the potential role of selenium in the development and progression of cardiovascular disease has been investigated for decades, both observational and interventional studies of selenium supplementation remain inconclusive and are considered in this review. This review covers current knowledge of the role of selenium and selenoproteins in the human body and its functional role in the cardiovascular system. The relationships between selenium intake/status and various health outcomes, in particular cardiomyopathy, myocardial ischemia/infarction and reperfusion injury are reviewed. We describe, in depth, selenium as a biomarker in coronary heart disease and highlight the significance of selenium supplementation for patients undergoing cardiac surgery.

Association between copper levels and myocardial infarction: a meta-analysis

BACKGROUND AND AIMS

There are conflicting reports as to the correlation between copper (Cu) levels and myocardial infarction (MI). The purpose of the present study is to clarify the association between Cu levels and MI.

METHODS

We searched articles in Pubmed and the Chinese Journal Full-text Database published as of October 2014. A meta-analysis was used to pool estimates of the standardized mean difference (SMD) with 95% confidence interval (CI).

RESULTS

Pooled analysis indicated that subjects with MI had higher serum Cu levels than healthy controls (SMD = 1.629, 95%CI = [1.027, 2.232], Z = 5.30, p < 0.001). Further subgroup analysis stratified by ethnicity indicated that subjects with MI had higher serum Cu levels than healthy controls among members of the Asian race (SMD = 2.191, 95%CI = [1.401, 2.981], Z = 5.43, p < 0.001), but not among members of the Caucasian race (SMD = 0.411, 95%CI = [-0.030, 0.851], Z = 1.83, p = 0.068). The results obtained from hairs showed no association between MI and hair Cu levels (SMD = 0.338, 95% CI = [-0.171, 0.848], Z = 1.30, p = 0.193). But the subgroup analysis stratified by geological location indicated that subjects with MI had higher hair Cu levels than healthy controls in Pakistan (SMD = 0.785, 95% CI = [0.587, 0.983], Z = 10.29, p < 0.001), but not in India (SMD = -9.028, 95% CI = [-10.747, -7.309], Z = 7.77, p < 0.001).

CONCLUSION

This meta-analysis indicates a significant association between high serum Cu levels and MI. However, the subgroup analysis found that there was significant effect modification of Cu levels by ethnicity. Thus, we suggest that a trans-regional multicenter study is needed to obtain better understanding of causal relationships between Cu and MI in different human races.

Levels of selenium, zinc, copper, and cardiac troponin I in serum of patients with acute coronary syndrome

The aim of this study was to assess the levels of selenium (Se), zinc (Zn), copper (Cu), and troponin I (TnI) in patients with acute coronary syndrome (ACS) on admission to our emergency department in comparison to healthy control subjects. Patients with diagnosed ACS (n = 100) were included in the study group. Control subjects (n = 100) were selected from healthy volunteers in the same age range. Venous blood samples were obtained to evaluate the levels of Se, Zn, Cu, and TnI (on admission for the ACS group). Serum Se, Zn, and Cu levels were significantly less in the ACS group compared to the control group (p <0.001, p <0.01, and p <0.001, respectively). The serum TnI level was significantly greater in the ACS group compared to the control group (p <0.05). The serum Se level in the ACS group correlated significantly with the TnI level (r = -0.211, p = 0.035). These results indicate that Se, Zn, and Cu deficiencies may be risk factors for ACS, and a decreased serum Se level in patients with ACS might reflect the degree of myocardial necrosis.

Biological effects of selenium compounds with a particular attention to the ontogenetic development

Selenium is a trace element that is essential for living organism. Its beneficial effect is, however, expressed in a very narrow dosage range: the high and low doses of selenium are connected with pathological manifestations. The toxicity depends on the chemical form of selenium, state of organism, interactions with heavy metals and on the stage of ontogenetic development. Whereas one dose of sodium selenite (20 micromol/kg b.w.) is lethal in adult rats, suckling rats are entirely resistant. However, within one week after administration of the same dose, cataract of eye lens developed. The highest incidence of cataract was observed in 10-day-old animals and it decreased until day 20. From postnatal day 20 to day 40 the rats were resistant to both the lethal and cataractogenic effects of selenium. The incidence of cataract may be suppressed by premature weaning, lower hydration of suckling, change of water soluble/water insoluble lens protein ratio, thyroxine treatment, and by interaction with mercury. By means of its oxidative and reduction properties, selenium is involved in the maintenance of the cell redox homeostasis. Typical example is its possible cardioprotective effect: selenium decreased number of arrhythmias, reduced infarct size and improved the contractile recovery after ischemia/reperfusion injury. Selenium supplementation may thus increase cardiac tolerance to ischemic damage.

Evaluation of copper concentration in subclinical cases of white muscle disease and its relationship with cardiac troponin I

The present study aims to evaluate the serum level of copper (Cu) in lambs suffering from subclinical forms of white muscle disease (WMD) and its relationship with cardiac troponin I (cTn-I) as a novel biomarker of cardiovascular disorders. Ten milliliters of jugular blood were taken from 200 lambs less than one year old to measure serum concentrations of Cu, selenium (Se), and cTn-I. The subjects were divided into 2 groups, namely, the deficient group which included 36 lambs, and the control group which included 164 lambs according to the reference serum Se concentration (50 ng/mL). Serum Se levels in the deficient group were lower than 50 ng/mL. By contrast, the control group showed Se levels higher than 50 ng/mL. Differences among the serum Cu and cTn-I levels were determined in both groups. The mean ±SD and median of serum Cu and cTn-I levels in the deficient group were lower and higher than those in the control group, respectively. A significant positive correlation was observed between serum Cu and Se levels, and also serum Cu and Se levels showed a negative correlation with serum cTn-I concentrations. Stepwise linear regression analysis showed that serum Cu levels were correlated positively with serum Se levels (p<0.05). Receiver operating characteristic (ROC) curve analysis indicated that the area under curve (AUC) of Cu was significantly higher than that of cTn-I based on the reference diagonal line. It is important to keep in mind that the value of AUC for the ROC curve is between 0.5 and 1.00, in which the lowest accuracy is related to the reference diagonal line with AUC of 0.5. A cut-off was determined to indicate which Cu level can discriminate between affected and healthy lambs. The cut-off level, sensitivity, and specificity of Cu in this study were 144.5 ng/mL, 74%, and 61%, respectively.