Blood cadmium level and hypertension in humans

[Blood cadmium and plasma zinc in hypertensive patients. Apropos of 76 cases]

Changes in total blood cadmium level (CdT), in blood plasma Zinc level (ZnP) and in CdT/ZnP ratio were studied in 39 hypertensive patients compared to 37 healthy subjects. The hypertensive patients were caracterized by a higher CdT level (p less than 10(-5)), a lower ZnP level (p less than 10(-7)) and a higher CdT/ZnP ratio (p less than 10(-7)). A negative correlation was found between CdT and ZnP, and between blood pressure values (systolic and diastolic) and ZnP. A positive correlation was found between blood pressure values and CdT, and therefore CdT/ZnP ratio.

Selenium and vitamin E in relation to risk factors for coronary heart disease

Fasting blood samples taken from 116 apparently healthy men aged 30-50 years were assayed for selenium, glutathione peroxidase activity, vitamin E, cadmium, lead, glucose, lipids, and albumin. Blood pressure was measured in each subject, and details of height, weight, smoking habits, and alcohol consumption were recorded. Multivariate analysis of the data showed that the decrease in blood and serum concentrations of selenium and the increase in whole blood cadmium concentrations in the cigarette smokers was independent of alcohol consumption. There was no correlation between blood selenium concentrations or glutathione peroxidase activities and the risk factors for cardiovascular disease. Neither alcohol consumption nor smoking had an effect on the vitamin E concentrations. There was a strong association, however, between vitamin E and serum lipid concentrations, although the increase in triglyceride concentrations in the smokers was not matched by a comparable increase in vitamin E. The possible role of selenium in the aetiology of heart disease remains unresolved.

Effect of cadmium on arterial blood pressure and lipid metabolism in rats

A total dose of 8 mg cadmium acetate/kg body weight was administered by repeated i.p. injection to female Wistar rats for 12 weeks. Slight, but significant, increases in blood pressure were recorded. The lipid concentration in serum and other tissues examined was not significantly affected, apart from a decrease in hepatic triglyceride. The blood cadmium (Cd) concentration was increased 10 times and Cd in the aortic wall was 4 times higher in treated rats. Cd affects hepatic lipid metabolism and it is considered that the increase in blood pressure is associated with accumulation of Cd in the arterial walls.

Method for the simultaneous determination of cadmium and zinc in whole blood by atomic absorption spectrophotometry and measurement in normotensive and hypertensive humans

A method is described for the analysis of whole blood cadmium and zinc by extraction and atomic absorption spectrophotometry, in which cadmium is analyzed using a graphite furnace, and zinc using an air-acetylene flame with a single slot burner, after dilution of the extract. Recoveries for cadmium and zinc were 100% and 106%, respectively. For cadmium the day-to-day and within-run coefficients of variation were all less than 13% at low concentrations (approximately 27 nmol/1) and 6% or less at high concentrations (approximately 89 nmol/1). For zinc the coefficients of variation for day-to-day and within-run analyses were less than 6% at low (approximately 76 mumol/1) and high concentrations (approximately 138 mumol/1). The sensitivity of the procedure is 0.5 nmol/1 for cadmium and 1.2 mu mol/1 for zinc. Whole blood from 72 normotensive volunteers, 56 treated hypertensives, and 15 untreated hypertensives were analyzed using this method. Cadmium levels were elevated in smokers but not significantly affected by age or sex. Zinc levels were higher in males than in females, but not significantly affected by smoking. Levels of cadmium and zinc were increased in treated hypertensives and greater still in untreated hypertensives. Significant elevations were found for cadmium in treated hypertensive females who smoked, treated and untreated hypertensive male non-smokers, and for the cadmium to zinc ratio in these later two groups.

Influence of dosage, consciousness, and nifedipine on the acute pressor response to intraperitoneally administered cadmium

The acute pressor effect of intraperitoneally administered cadmium was explored over the dose range 0.015-2 mg/kg in both pentobarbital-anesthetized and conscious rats. The former first respondent at 0.031 mg/kg, and successive doublings of that dosage increased the highest pressures attained in a stepwise fashion until a dosage of 0.25 mg/kg, the maximally effective quantity, was reached. Arterial pressure did not rise in conscious rats until a dose of 1 mg/kg, which gave the maximum response within the range examined. Heart-rate changes with Cd were slight, and rarely significant at a given dosage, but pentobarbital invariably caused tachycardia. Anesthetized rats thus gave a graded response, while conscious animals reacted in an all-or-none fashion. The increased pressor responsiveness of rats under pentobarbital can not be ascribed to its cardiac parasympatholytic effects, since sensitivity was not conferred upon conscious rats when pretreated with atropine at a dose producing even greater tachycardia than that caused by pentobarbital. Nifedipine, which blocks calcium entry into smooth muscle cells, prevented the pressor response to cadmium when given as pretreatment and terminated an ongoing response when give intercurrently. Possible mechanisms to account for the observed behavior are considered.