Effect of diuretics on captopril-induced urinary zinc excretion

Zinc as nutritional intervention and prevention measure for COVID-19 disease

The present spread of severe acute respiratory syndrome coronavirus 2, provoking COVID–19 disease, progresses rapidly worldwide. In current absence of a curative treatment and an effective, safe vaccine, there is a pressing need to focus on identifying and correcting deficits in immune function in order to reduce risk of severe progress of the disease and to lower the number of infections and fatalities. This paper evaluates the most recent literature on zinc status related to antiviral immunity and its possible role in COVID–19. It is concluded that zinc is a critical factor for antiviral immunity. There is ample evidence suggesting that zinc depletion, also prevalent in high–income nations, compromises immune functions. Notably, major risk groups for COVID–19, the elderly, men more than women, obese individuals and patients with diabetes are all at risk of zinc deficiency. Moreover, various widely used antihypertensive drugs and statin therapy have been reported to negatively influence zinc status. As zinc depletion impairs antiviral immunity, it is hypothesised to increase susceptibility for COVID–19. Therefore, dietary preventive measures and prompt implementation of zinc supplementation for risk groups should be considered. Large–scale studies are urgently needed to investigate the role of micronutrients and antiviral immunity, in particular drug–micronutrient immunity interaction.

Pharmaco-nutrient interactions - a systematic review of zinc and antihypertensive therapy

BACKGROUND

Antihypertensive medicines are to known to cause diverse disturbances to electrolyte homeostasis; however, their potential to affect zinc is less well known. The primary aim was to explore whether antihypertensive medicines have the potential to affect zinc status.

METHODS

A review of electronic databases was undertaken. Full-length English language articles describing clinical trials involving antihypertensive medicines and reporting on zinc measurements were reviewed.

RESULTS

Eight eligible studies were identified which involved the use of ACE inhibitors, thiazide diuretics, beta blockers, or ARB drugs of which five included a control group Studies used urinary zinc excretion, plasma zinc levels or erythrocyte zinc as key measures of zinc status. Studies reported increased urinary zinc losses for captopril (from 50 mg/day), enalapril (20 mg/day), losartan (50 mg/day), losartan (50 mg/day) together with hydrochlorothiazide (12.5 mg/day), captopril (75 mg/day) together with frusemide (40 mg/day) and stand-alone hydrochlorothiazide (25 mg/day). Serum levels of zinc decreased with captopril (50-150 mg/day), verapamil (240 mg/day), atenolol (50-150 mg/day) and the combination of losartan (50 mg/day) and hydrochlorothiazide (12.5 mg/day), eryrthrocyte levels decreased with use of valsartan (80 mg/day) and in some studies for captopril, but not for metoprolol (100 mg/day), atenolol (50-150 mg/day), verapamil (240 mg/day), doxazosin (4 mg/day) or amlodipine 10 mg/day). Major limitations were that most studies were small and did not report on dietary zinc intake.

CONCLUSION

The available evidence suggests that use of ACE inhibitors and angiotensin 2 receptor antagonists or thiazide diuretics have the potential to reduce zinc levels in hypertensive patients. Additional research using larger participant numbers and accounting for dietary zinc intakes are required.

Sodium restriction improves the gustatory threshold for salty taste in patients with chronic kidney disease

Sodium restriction is important in the treatment of chronic kidney disease; however, it is sometimes difficult to achieve. Decreased taste sensitivity may be a factor influencing inadequate control of oral salt intake and subsequent high blood pressure. To measure this, the gustatory threshold (recognition and detection) for salty taste was determined in 29 patients with chronic kidney disease using a sodium-impregnated test strip and relevant factors determining taste sensitivity were analyzed. Compared with 11 healthy volunteers, recognition and detection thresholds were increased in the patients with chronic kidney disease. Oral sodium intake correlated positively but serum zinc correlated negatively with the recognition threshold. Patients with diabetic nephropathy had a higher detection threshold than non-diabetic patients. Both recognition and detection thresholds were increased in patients with diuretic administration. After 1 week of sodium restriction, the average recognition threshold decreased significantly. Our study verified that latent taste dysfunction and zinc deficiency are common in patients with chronic kidney disease. Further, the recognition threshold for salty taste improved even after a short period of salt restriction.

Selected zinc metabolism parameters and left ventricle mass in echocardiographic examination in primary arterial hypertension

The basal systolic and diastolic blood pressure, body mass index, left ventricular mass, serum and lymphocyte zinc levels, serum aldosterone, plasma rennin and angiotensin-converting enzyme activities, sodium and potassium levels, and the total and ouabain-dependent rate constants of zinc efflux from lymphocytes were measured in a group of 41 individuals of both sexes (overall age 46.3 +/- 11.4 years), of which 18 were women (48.5 +/- 7.1 years old) and 23 were men (44.7 +/- 13.8 years old). There were no significant differences between these parameters while dividing the subjects into groups according to sex, despite differences in weight, left ventricle mass, plasma rennin activity, and serum aldosterone content. Only the total and ouabain-dependent rate constants of zinc efflux from lymphocytes slightly negatively correlated to left ventricular mass, r = -0.30 to r = -0.36. This may constitute indirect evidence of zinc deficiency in cardiomyocytes of some hypertensive individuals with left ventricular hypertrophy.

Effects of angiotensin-converting enzyme inhibitors (ACE i) on zinc metabolism in patients with heart failure

The aim of this study is to investigate the effects of angiotensin-converting enzyme (ACE) inhibitors and furosemide on zinc metabolism by assessing serum zinc and urine levels in hospitalized subjects. We recruited 11 patients with heart failure from the Internal Medicine Department; these patients had been hospitalized less than 72 h before. Heart failure was defined using clinical and radiological signs. Serum zinc concentrations were measured using an air/acetylene flame atomic absorption spectrophotometer. Urine zinc levels were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Data were obtained from the 11 patients and 24 healthy controls matched for age and sex. Results indicate higher urine zinc levels and lower concentrations of zinc in serum in heart failure patients vs matched controls (p<0.05). This study suggests that treating heart failure patients with ACE inhibitors may result in zinc deficiency.

Role of zinc in regulation of arterial blood pressure and in the etiopathogenesis of arterial hypertension

Increased gastrointestinal absorption and urinary excretion of zinc has been confirmed in experimental and clinical studies on primary arterial hypertension as a result from changes of intracellular and extracellular zinc content. In arterial hypertension, the levels of zinc in serum, lymphocyte, and bone decrease while increasing in heart, erythrocytes, kidney, liver, suprarenal glands and spleen. These changes result in the loss of zinc homeostasis that leads to various degrees of deficiency, not entirely compensated by nutritional factors or increased absorption in the gastrointestinal tract. Loss of zinc homeostasis can be both cause and effect of high blood pressure. In the present review, the role of zinc metabolism changes and its mechanisms in arterial hypertension are discussed.

Zinc balance and medications commonly used in the management of heart failure

Heart failure (HF) is a prevalent syndrome resulting in a high mortality rate. HF may be associated with zinc deficiency through a reduction in dietary intake, decreased absorption due to gastrointestinal edema, impaired motility or intestinal zinc losses. Diseases concomitant with HF such as diabetes mellitus (DM) and hypertension may enhance zinc deficiency. Medications given for HF may affect zinc metabolism in different ways. It was shown that thiazides may cause zincuria and a decrease in tissue zinc concentration. There is conflicting evidence about furosemide, even though patients with chronic furosemide treatment showed low tissue zinc levels in autopsies. Treatment with angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) resulted in zincuria and zinc deficiency, but this outcome was not consistent in all studies. Beta-blockers did not alter plasma zinc concentration. Matrix metalloproteinases (MMPs) and ACE are zinc-containing enzymes, which play a role in the process of remodeling in HF. It was shown that ACE inhibitors may inhibit the activity of different MMPs. The exact interrelationship between HF, zinc-containing enzymes, zinc deficiency and the clinical manifestation of HF has to be investigated.

Effects of captopril and enalapril on zinc metabolism in hypertensive patients

OBJECTIVE

To investigate the effect of chronic captopril and enalapril treatment on zinc metabolism in hypertensive patients by assessing zinc levels in serum, urine and monocytes.

METHODS

Patients with newly diagnosed essential hypertension were randomly divided into two treatment groups: those treated with captopril only (n = 16) and those treated with enalapril only (n = 18). Ten healthy subjects served as controls. Prior to the start of treatment and again 6 months later, zinc was assessed in the serum, in urine collected over 24 hours, and in peripheral blood monocytes.

RESULTS

Significant enhancement of 24-hour urinary zinc excretion (micrograms/24 hour) after 6 months of treatment was observed only in the captopril-treated group (p < 0.01). However, intramonocytic zinc levels decreased significantly in both of the treated groups over the same period (p < 0.01 and P < 0.04 in the captopril- and enalapril-treated groups, respectively).

CONCLUSION

Treatment of hypertensive patients with captopril or enalapril may result in zinc deficiency.

Type II diabetes mellitus, congestive heart failure, and zinc metabolism

Zinc status was assessed in patients with type II diabetes mellitus and congestive heart failure (CHF). Three groups of patients were enrolled into the study: Group 1: 15 patients with type II diabetes mellitus and CHF; Group 2: 20 patients with isolated type II diabetes mellitus; and Group 3: nine patients with isolated CHF. Twenty-four-hour urine was measured for creatinine, protein, and zinc, and blood was drawn for creatinine, proteins, liver enzymes, hemoglobin A1c, and zinc. Insulin treatment and hemoglobin A1c were comparable in the diabetic patients of groups 1 and 2, but group 1 was also treated with captopril and diuretics like the CHF patients of group 3. Plasma zinc levels were statistically similar in all three groups, but urinary zinc excretion (mumol/24 h) and urinary zinc: creatinine (mumol/mmol) ratio were significantly higher in the type II diabetics and CHF group (27.2 +/- 1.5; 1.69 +/- 0.6, respectively) compared to the diabetic patients alone (19.4 +/- 0.76; 0.97 +/- 0.3, respectively) and the CHF patients (9.7 +/- 0.3; 0.62 +/- 0.3, respectively). and the CHF patients (9.7 +/- 0.3; 0.62 +/- 0.3, respectively). Patients with type II diabetes mellitus and CHF were treated with higher doses of captopril than the CHF patients (56.25 +/- 24 mg vs 18.8 +/- 11 mg P < 0.05). Thus, patients with type II diabetes mellitus and CHF excrete larger amounts of zinc, which may eventually lead to zinc deficiency.