Comparative Studies on the Distribution, Correlation and Multivariate Apportionment of Selected Elements in Blood and Scalp Hair of Cardiovascular Patients and Healthy Donors

Abstract

Cardiovascular disease has become a ubiquitous cause of morbidity and a leading contributor to mortality worldwide. Numerous epidemiological studies showed intimating development of cardiovascular disease caused by elemental imbalance. Therefore, the present study was designed to investigate the concentrations of selected essential, trace and toxic elements (Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Pb, Sr and Zn) in the scalp hair and blood samples of the three different types of cardiovascular patients (angina patients, myocardial infarction patients and valvular heart disease patients) in comparison with their counterpart healthy donors/controls. Flame atomic absorption spectrophotometer was used for the quantification of selected elements by employing the nitric acid/perchloric acid-based wet digestion method. In the scalp hair of the angina patients, dominant mean levels were found for Ca (3310 μg/g), Mg (351.1 μg/g), Zn (278.6 μg/g) and Na (251.3 μg/g), while the healthy donors showed higher concentrations for Ca (2201 μg/g), Na (590.7 μg/g), Mg (548.1 μg/g) and Zn (289.8 μg/g) in their scalp hair. Likewise, in the scalp hair of myocardial infarction patients, higher contributions were noted for Ca (2265 μg/g), Mg (604.7 μg/g), Zn (264.4 μg/g), Na (206.1 μg/g) and Sr (103.4 μg/g). In addition, an elevated mean levels were observed for Ca (1862 μg/g), Mg (667.7 μg/g), Zn (342.5 μg/g) and Na (114.9 μg/g) in the scalp hair of valvular heart disease patients. On the average basis, the concentrations of Ca, Cd, Co, Cr, Fe, Li, Pb and Sr were significantly higher in the scalp hair of angina and myocardial infarction patients in comparison with healthy donors; whereas mean contents of Cu, Fe, Mg, Mn, Pb and Sr were significantly elevated in the scalp hair of valvular heart disease patients compared to the matching healthy donors. In a correlation study, strong relationships (r > 0.500) in the scalp hair of angina patients were observed for Cr-Fe, Fe-Li, Cr-Li, Mn-Fe, Cu-Li, Fe-K, Co-Fe, Co-Li and Co-K, whereas, the strong correlations were found for Ca-Mg, Sr-Ca, Cu- K, Cu-Sr, Zn-Mg, Mg-Sr, K-Sr, Ca-Mn, Ca-Cu, Ca-Zn, Ca-K, Ca-Na, Cd-Pb, Mg-Na and Cu-Mn in the scalp hair of myocardial infarction patients. However, significantly positive correlations were noted between Ca-Sr, Cu-Sr, Mg-Sr, Ca-Mn, Na-K, Mg-Mn, Mn-Sr, Ca-Cu and Ca-Mg in the scalp hair of valvular heart disease patients. The correlation behaviour of the elements in the scalp hair of healthy donors remained was noticeably diverse compared with all three types of the patients. Principal component analysis (PCA) of the data revealed four PCs for angina and myocardial infarction patients and five PCs for valvular heart disease patients, with significant diverse loadings. Cluster analysis (CA), also evidenced a significantly divergent pattern of elemental clustering in the scalp hair of three categories of the patients compared with counterpart healthy donors. In the case of the blood samples, angina patients showed higher contributions for Na (1446 μg/g), Fe (480.5 μg/g), K (469.5 μg/g), Mg (32.35 μg/g), Ca (31.92 μg/g) and Zn (9.309 μg/g), while higher average levels in healthy donors were noted for Na (1083 μg/g), K (767.1 μg/g), Fe (346.0 μg/g), Ca (102.9 μg/g), Mg (37.24 μg/g) and Zn (6.133 μg/g). Similarly, dominant mean levels were found for Na (1658 μg/g), K (1507 μg/g), Fe (408.9 μg/g), Ca (85.75 μg/g), Mg (35.51 μg/g), Pb (8.868 μg/g) and Zn (7.968 μg/g) in the blood of myocardial infarction patients. In case of valvular heart disease patients, average blood levels of Na, K, Fe, Ca, Mg and Zn were 1151, 1123, 417.3, 46.30, 34.68 and 8.538 μg/g, respectively. Mean concentrations of Cd, Co, Cr, Fe, Li, Mn, Sr and Zn were found to be significantly higher in the blood of all the three categories of patients compared with the healthy donors. The correlation study revealed strong correlations (r > 0.500) between Cu-K, Zn-K and Cu-Zn in the blood of angina patients, while strong positive relationships were noted among Li-Cd, Cr-Li, Cr-Cu, K-Zn, Li-Na, Cd-Cr, Li-Mn, Cu-Li and Li- Pb in the blood of valvular heart disease patients. PCA of the elemental data revealed five significant PCs for angina and valvular heart disease patients and six PCs for myocardial infarction patients, but with noticeably different loadings from the counterpart healthy donors, duly supported by the CA. Measured elemental levels in the patients and healthy donors were also compared in each matrix based on age, gender, abode, dietary habits, smoking habits and occupations; some noticeable differences were observed in both categories. In addition, the role of trace elements in the development of the disease was also discussed. Comparative evaluation of the elemental levels in cardiovascular patients and healthy donors exhibited considerable variations among the patients and controls for both matrices. Present elemental levels in the scalp hair and blood of different donor groups were also compared with the counterpart data reported from different regions of the world. Current mean contents of Cr, Mn, Pb and Sr showed elevated concentrations in the scalp hair and blood of cardiovascular disease patients compared with the studies conducted in other parts of the world. Overall, the present study indicated significant disparities in the distribution, mutual correlations and multivariate apportionment of selected metals in the scalp hair and blood samples of cardiovascular patients compared with the healthy donors. Hence, these elemental variations together with other factors may guide the practitioners to diagnose and suggest the treatment for the cardiovascular disease.