Gender differences in selected zinc metabolism parameters in patients with mild primary arterial hypertension

The relationship between selected zinc (Zn) metabolism parameters, arterial blood pressure, age, and renin-angiotensin-aldosterone system in subjects of both sexes with mild primary arterial hypertension is presented in this study. The following parameters were measured: systolic and diastolic arterial blood pressure, total and ouabain-dependent efflux rate constants of Zn from lymphocytes, serum and lymphocyte Zn concentrations, serum aldosterone, angiotensin-converting enzyme, sodium and potassium concentrations, body mass index, and plasma rennin activity. When all subjects are taken into account, no significant age-related differences were found for serum Zn. If divided into men and women, negative (r=−0.39) and positive (r=0.34) correlations are observed, respectively. Lymphocyte Zn correlated negatively with age in the entire group (r=−0.55) and also for men (r=−0.54) and women (r=−0.57). The renin-agiotensin-aldosterone system parameters correlated with those of Zn metabolism only for women: plasma rennin activity with total Zn efflux from lymphocytes (r=−0.33) and with lymphocyte Zn (r=0.71); the angiotensin-converting enzyme with total Zn efflux from lymphocytes (r=−0.35), with the oubain-dependent Zn efflux from lymphocytes (r=−0.33) and with lymphocyte Zn (r=0.57); serum aldosterone with oubain-dependent Zn efflux from lymphocytes (r=−0.44) and with lymphocyte Zn (r=0.59). For the men, the only positive correlation was that of serum Zn and aldosterone (r=0.45). In all cases (men and women), there was no negative correlation between serum Zn and angiotensin-converting enzyme. In women, the diastolic blood pressure correlated negatively with total Zn efflux from lymphocytes (r=−0.39), oubain-dependent Zn efflux from lymphocytes (r=−0.49), and serum Zn (r=−0.46); systolic blood pressure correlated negatively with lymphocyte zinc (r=−0.38). In men, the systolic blood pressure had a negative correlation with lymphocyte zinc (r=−0.32), which was also true for the entire group (r=−0.34). These results clearly show gender-related differences in Zn metabolism and indicate the need for further research to elucidate the possible causes of this phenomenon not only for Zn but for other elements as well.     

Selected zinc metabolism parameters in women with arterial hypotension

In the present study, differences between selected zinc parameters in healthy women and arterial hypotension patients were compared. The patients had baseline systolic blood pressure that did not surpass 100 mmHg. During the orthostatic test, a decrease of over 20 mm Hg was seen and the patients reported dizziness, limpness, and palpitations. The patients had higher levels of lymphocyte zinc than those of the controls and exhibited a positive correlation between serum zinc and the ouabain-dependent zinc efflux from lymphocytes (r=0.49), and, in turn, this efflux was negatively correlated to the serum aldosterone level (r=−0.35). Except for the differences in their systolic blood pressure and lymphocyte zinc, none of the tested zinc metabolism parameters showed significant differences between the patients and the controls. As in arterial hypertension, the obtained results indicate that zinc plays a significant role in regulation of arterial blood pressure.     

Zinc content in lymphocytes and the activity of zinc ion efflux from lymphocytes in primary arterial hypertension

Clinical observations and experimental data show that zinc (Zn) plays a role in regulating arterial blood pressure and in arterial hypertension etiopathogenesis. To determine the direction of changes in Zn metabolism in primary arterial hypertension, Zn absorption from the alimentary tract, Zn levels in blood serum, its content in lymphocytes, Zn efflux rate constants from lymphocytes, and urinary Zn excretion in patients with hypertension and in healthy subjects were studied. In this article, Zn levels in blood serum, its content in lymphocytes, and Zn efflux rate constants from lymphocytes are presented. In primary arterial hypertension, on the basis of this study, decreasing Zn levels in blood serum and its decreasing content in lymphocytes were found. The Zn efflux rate constants from lymphocytes increased at the initial stage of hypertension (mild arterial hypertension) and decreased in the late stage of the hypertension disease (severe arterial hypertension). Taking into consideration all of the directions of changes and the fact that Zn can be a factor that increases arterial blood pressure, the changes in Zn distribution can be regarded as having, to a certain extent, a protective character leading to weakening of the pressor reaction, assuming a genetic existence of relative or absolute Zn excess in the body. The changes of Zn distribution can lead, after some time, to Zn deficiency and the resulting metabolic changes (e.g., carbohydrate intolerance).     

Selected zinc metabolism parameters in premenopausal and postmenopausal women with moderate and severe primary arterial hypertension

The aim of this study was to compare zinc (Zn) metabolism parameters in groups of premenopausal and postmenopausal women with moderate and severe primary arterial hypertension. The study included 38 women, of which 15 were premenopausal and 23 were postmenopausal. Postmenopausal women had a positive correlation between total (ERCt-Zn) and oubain-dependent (ERCos-Zn) rate constants of Zn efflux from lymphocyte (k = 0.52). In premenopausal women’s ERCos-Zn was negatively but weakly correlated with serum Zn (Zn-s) (k = 0.35). The Zn ERCt-Zn and ERCos-Zn did not show any correlation with age, as did Zn-s. Lymphocyte Zn correlated negatively with age only in premenopausal women (k = -0.62). The renin-angiotensin-aldosterone system correlated with Zn metabolism parameters. In premenopausal women, plasma renin activity and serum aldosterone showed positive correlations with lymphocyte Zn (Zn-l) (k = 0.63 andk = 0.41, respectively), and in postmenopausal women, it correlated negatively with Zn-s (k = -0.38) and whole aldosterone correlated negatively with ERCos-Zn (k = -0.41). Positive correlations between Zn metabolism parameters and arterial blood pressure in premenopausal women were as follows: ERCt-Zn with diastolic blood pressure (dRR) (k = 0.40) and ERCos-Zn with dRR (k = 0.47). In postmenopausal women, the correlations between ERC-t-Zn and dRR and systolic blood pressure (sRR) were negative (k = -0.53 andk = -0.63, respectively). A similar situation was observed between dRR and sRR and Zn-s (k = -0.40 andk = -0.38, respectively). The body mass index (BMI) was positively correlated with ERCt-Zn in premenopausal women (k = 0.36), whereas in postmenopausal, it was negatively correlated with ERCos-Zn (k = -0.42). For the whole group, negative correlations were seen between ZnS and dRR and sRR (k = -0.36 andk = -0.39, respectively) and between ERCos-Zn and BMI (k = -0.39). The results presented show differences in Zn metabolism in arterial hypertension between premenopausal and post-menopausal women. The role of estrogens in these differences is disscused.     

Zinc ions efflux from lymphocytes in vitro in the presence of a calcium and magnesium ionic environment and its changes following administration of verapamil

The total and ouabain-dependent rate constants of efflux of zinc (Zn) ions from lymphocytes isolated from healthy subjects were measured in vitro in an environment containing calcium (Ca) and magnesium (Mg) ions. Both the total (ERCt-Zn) and ouabain-dependent (ERCos-Zn) rate constants were higher in the presence of Mg²⁺, with the the oubain-dependent efflux significantly different 0.29±0.07 vs 0.13±0.02 with and without Mg²⁺, respectively (p<0.001). After the addition of verapamil, an increase of ERCE-Zn was observed in both ionic environments and was higher and statistically significant in the presence of Mg²⁺: 1.94±0.64 vs 2.97±1.16 (p<0.025). These results suggest that verapamil has an enhancing effect on Zn efflux from isolated lymphocytes, suggesting that calcium channel blockers might result in better Zn homeostatic regulation in diseases of the cardiovascular system.     

Selected zinc metabolism parameters in relation to insulin, renin-angiotensin-aldosterone system, and blood pressure in healthy subjects

The relationship between the renin-angiotensin-aldosterone system and insulin concentration and selected zinc (Zn) metabolism parameters and arterial blood pressure in young healthy subjects of both sexes is presented in this study. The following parameters were measured: systolic and diastolic arterial blood pressure, total and ouabain-dependent efflux rate constants of Zn from lymphocytes, serum and lymphocyte Zn concentrations, serum aldosterone, angiotensin-converting enzyme, insulin, sodium and potassium concentrations, body mass index, and plasma rennin activity. The correlations among these parameters show gender-dependent differences, except for a negative correlation between serum Zn and ouabain-dependent Zn efflux rate constant and the serum level of angiotensin-converting enzyme, and a positive relationship between the total efflux rate constant of Zn from lymphocytes and the serum aldosterone levels, both of which were gender independent. The results led us to conclude that there is a gender-independent functional relation between Zn homeostasis and the renin-angiotensin-aldosterone system. Insulin does not appear to play a significant role in Zn homeostasis.     

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.     

Changes in zinc metabolism following exercise in human subjects

Changes in zinc (Zn) availability in muscle tissue that influence muscle performance in vitro have been observed. The effect of exercise of plasma Zn levels and urinary excretion of Zn was observed in sever untrained volunteers following brief intensive exercise and in seven trained volunteers after more prolonged road-running exercise. With brief exercise, plasma Zn decreased predominantly in the more loosely bound albumin fraction. Prolonged exercise resulted in a greater plasma Zn decrease of 30%. Urinary Zn excretion increased transiently with minimal effect on daily losses. However, weight loss by sweating was significant, and sweat Zn losses were greater than those in the urine. Exercise resulted in changes in Zn metabolism that may influence performance.     

Increased absorption of zinc from alimentary tract in primary arterial hypertension

Zinc absorption from the alimentary tract, as revealed by serum zinc concentration, was studied in a group of 10 patients (age 37.7±5.1 yr) with moderate and severe untreated primary arterial hypertension before and after a 30-d treatment with perindopril 4 mg/d. Blood pressure was 177.33±16.24/111.33±15.26 mm Hg before and 143.41±17.34/91.29±12.54 mm Hg after treatment (p<0.05/p<0.05). Nine persons (age 37±6.2 yr) with normal blood pressure (121.33±9.9/78±5.23 mm Hg) were the control group. Blood samples were taken from the ulnar vein at 8.00 am (0 h), before taking zinc orally (one tablet of Zincas (zinc aspartate), containing 5 mg Zn²⁺) and at 1, 3, and 6 h after the dose. Serum zinc concentration in control and hypertensive group (before treatment) were initially 15.47±6.26 versus 15.99±5.65 (NS), 19.37±6.40 versus 20.83±4.48 (NS) after 1 h, 17.91±4.76 versus 31.32±10.49 (p<0.003) after 3 h, and 15.32±5.47 versus 17.87±6.56 (NS) after 6 h. Maximal increase of Zn was 4.77±2.10 versus 17.53±4.13, respectively (p<0.001). In the hypertensive group, serum Zn before and after perindopril treatment was initially 15.98±5.65 versus 14.81±3.11 (NS), 20.83±4.48 versus 18.17±2.50 (NS) after 1 h, 31.32±10.49 versus 22.94±5.80 (NS) after 3 h, 17.53±4.13 (p<0.001) after 6 h. Maximal increase of Zn before treatment was 17.53±4.13 versus 9.17±4.67 (p<0.017) after treatment. The following conclusions were reached: (1) In patients with primary arterial hypertension, an increased zinc absorption from alimentary tract was found; (2) A 30-d perindopril treatment 4 mg/d orally decreased zinc absorption in these patients.     

Urinary zinc excretion is normalized in primary arterial hypertension after perindopril treatment

Increased or unchanged urinary zinc excretion has been reported in hypertension. In the present article, this observation was confirmed in a group of 10 untreated hypertensive patients of both sexes that had no diabetes or obesity. The 24-h zinc excretion was significantly different between the patients: 7.46±3.01 μmol and healthy controls: 5.19±2.19 μmol (p<0.025). After a 1-mo treatment with 4 mg perindopril per day, a decrease of urinary zinc was observed until it reached levels not significantly different from those of the healthy controls (5.98±2.13 μmol). The decrease was significantly different from that of the pretreatment values (p<0.05).     

The changes of metabolism balance of zinc and copper in gastric juice with widely varying dietary zinc intake

The concentrations of zinc and copper in gastric juice of humans who had widely varying dietary zinc intake were evaluated. In order to compare this with zinc and copper levels of normal dietary individuals, we also determined the zinc and copper levels in healthy individuals' plasma and in cancer patient's natural tissue, all of whom had normal diets. The correlation coefficients between zinc and copper were 0.71, 0.45, and 0.55, respectively, in gastric juice, plasma, and tissue of normal dietary subjects. Such correlation changed and was destroyed when there was a high zinc level in gastric juice. When gastric juice zinc level changed from mean value 16.8 μmol/L to 262.5 μmol/L, the correlation coefficient varied from 0.71 to −0.04, and the copper level also varied from mean value 8.96 μmol/L to 4.89 μmol/L. These findings probably give the evidence to suggest that a high zinc level will restrain the copper level and break the balance of the human body's zinc and copper metabolism.     

Correlations between serum zinc concentrations and oxygen balance parameters in patients with primary arterial hypertension

It has been postulated that increased blood pressure is related to hypersensitivity of arterial chemoreceptors and increased tissue oxygen supply. Arterial blood pressure has been found to be negatively correlated to serum zinc and positively correlated to age, body mass index, and hemoglobin concentrations. The aim of the present investigation was to further explore the relationship between blood pressure and zinc concentrations in serum and blood morphology parameters, iron concentrations, and venous blood gasometry parameters. The study was carried out in two groups. Group Aconsisted of 23 subjects of both sexes suffering from moderate to severe arterial blood pressure. Their mean age was 53.13±10.45 yr (range: 23–74 yr). Group B included 48 subjects of mean age 36.7±10.0 yr (range: 26–60 yr). This group included 5 patients with arterial hypotension, 37 with hypertension, and the remaining 6 with normal blood pressure. Significant positive correlations between serum zinc and red blood cell count (r = 0.51) and negative with age (r = −0.52) were found. By multiple regression, negative correlations were also found between serum zinc and the diastolic blood pressure and with hemoglobin (r = −0.5). Age was positively correlated to systolic (r = 0.49) and diastolic (r = 0.45) blood pressure parameters and to hemoglobin concentrations (r = 0.33 and r = 0.38, respectively). Buffered and excess bases in blood were negatively correlated to zinc (r = −0.29 in both cases) and to systolic and diastolic blood pressure (r = −0.31 and r = −0.40, respectively). In turn, the systolic and diastolic blood pressure also correlated negatively to the partial pressure of carbon dioxide and positively to venous blood oxygen saturation and to the partial pressure of oxygen. The role of zinc and acid-balance realtionships in blood pressure regulation and in arterial hypertension ethiopatogenesis is disscused.     

Relationship among levels of leptin and zinc,copper, and zinc/copper ratio in plasma of patients with essential hypertension and healthy normotensive subjects

Obesity is among the main contributing factors in the etiology of essential hypertension (EHT). Leptin, the product of the ob gene, is expressed mainly in adipose tissue. We examined the relationship between two trace elements, zinc (Zn) and copper (Cu), and leptin in patients with EHT (n=35) and normotensive (NT) controls (n=50) because leptin as well as Zn and Cu were reported to be associated with the pathophysiology of EHT. Plasma leptin levels were determined with a commercial enzyme-linked immunosorbent assay (ELISA) kit. Atomic absorption spectrophotometry was utilized to determine plasma Zn and Cu levels. There was a negative correlation between leptin and Zn, and the Zn/Cu ratio (r=−0.359, p<0.05; r=0.361, p<0.05, respectively) in pooled subjects. When subjects were divided based on the presence or absence of hypertension, there was a negative correlation between leptin and Zn (r=−0.375, p<0.05) as well as leptin and Zn/Cu ratio (r=−0.398, p<0.05) in NT subjects. Similar trends were observed when leptin/BMI (body mass index) levels were utilized. There was no significant correlations between levels of Cu and leptin or leptin/BMI. In conclusion, in addition to high leptin levels, Zn and the Zn/Cu ratio were lower in patients with EHT compared to NT controls.     

Molecular distribution of zinc in biliary and pancreatic secretions

Rat bile and pancreatic fluid were examined for the presence of low molecular weight zinc complexes. Fluids were collected separately by cannulation, and zinc distribution in collected samples was analyzed by gel filtration on Sephadex G-50. Most of the zinc in bile was associated with low molecular weight zinc complexes; only a small amount of zinc was present in the high molecular weight fraction. In contrast, pancreatic secretions did not contain low molecular weight zinc complexes, but there were considerable amounts of zinc bound to high molecular weight compounds. The addition of zinc to bile resulted in an increased amount of zinc in the low molecular weight fraction, while the addition of zinc to pancreatic fluid resulted primarily in an increase in zinc bound to the high molecular weight components. Like pancreatic fluid, homogenates of pancreatic tissue had no low molecular weight zinc complex. In rats whose bile and pancreatic fluid were removed and not returned into the intestine, the amount of zinc bound to low molecular weight complexes in intestinal homogenates was reduced. This alteration of the molecular distribution of zinc in intestinal homogenates by removal of bile and pancreatic fluid suggests the potential importance of low molecular weight zinc complexes for zinc homeostasis.     

Effects of zinc supplementation on the plasma glucose level and insulin activity in genetically obese (ob/ob) mice

The effects of zinc supplementation (20 mM ZnCl₂ from the drinking water for eight weeks) on plasma glucose and insulin levels, as well as its in vitro effect on lipogenesis and lipolysis in adipocytes were studied in genetically obese (ob/ob) mice and their lean controls (+/?). Zinc supplementation reduced the fasting plasma glucose levels in both obese and lean mice by 21 and 25%, respectively (p < 0.05). Fasting plasma insulin levels were significantly decreased by 42% in obese mice after zinc treatment. In obese mice, zinc supplementation also attenuated the glycemic response by 34% after the glucose load. The insulin-like effect of zinc on lipogenesis in adipocytes was significantly increased by 80% in lean mice. However, the increment of 74% on lipogenesis in obese mice was observed only when the zinc plus insulin treatment was given. This study reveals that zinc supplementation alleviated the hyperglycemia of ob/ob mice, which may be related to its effect on the enhancement of insulin activity.     

Zinc nutritional status and its relationships with hyperinsulinemia in obese children and adolescents

A perturbation of zinc metabolism has been noted in subjects with obesity. The present work intends to investigate whether the zinc nutritional status is associated with hyperinsulinemia in obesity. A study was carried out in a group of obese children and adolescents (n=23) and compared to a control group (n=21), both between 7 and 14 yr of age. Software analyzed diet information from 3-d food records. Body composition was evaluated by body mass index (BMI), bioelectrical impedance, and skinfold measurements. Zinc nutritional status was evaluated by Zn determination in plasma, erythrocyte, and 24-h urine, by atomic absorption spectrophotometry (λ=213.9 nm). Insulin was measured by radioimmunoassay (Linco Res). Diets consumed by both groups had marginal concentrations of zinc. Zinc concentrations in plasma and erythrocytes were significantly lower in the obese group. Urinary zinc excretion and serum insulin were significantly higher in the same group, although the insulinemia and the parameters of zinc nutritional status were not significantly correlated. As a result, considering that zinc is part of the synthesis and secretion of this hormone, an assessment is necessary of the possible participation of the oligoelement in the mechanisms of insulin resistance, commonly present in obese patients.     

Speciation of zinc and tin(II) in dentrifices with reference to availability in saliva

Abstract

The chemical speciation of zinc- and tin(II)-containing dentrifices and of the reaction between saliva and such toothpastes has been researched using computer simulation. Pivotal formulation variables have been identified (phosphates, fluorides, citrate, etc.) and optimised to suggest formulations having maximum availability, of antimicrobial metal salts Zn²⁺ (aq) and soluble tin(II) species. Although the concept of having a single dentifrice in which both the zinc and the soluble tin(II) species are maximised together is desirable, it is concluded that at a single pH value, there cannot be maximal availability for both species, but it is possible to achieve levels of antimicrobial metal salts superior to a dentifrice containing either ingredient alone.     

Interrelationships of zinc with glucose and insulin metabolism in humans

Hyperzincemia has been reported to cause alterations in the homeostasis of glycid metabolism. To determine this effect on plasma glucose and insulin levels, we studied 36 normal individuals of both sexes aged 22–26 y after a 12-h fast. The tests were initiated at 7:00am when an antecubital vein was punctured and a device for infusion was installed and maintained with physiological saline. Zinc was administered orally at 8:00am. Subjects were divided into an experimental group of 22 individuals who received doses of 25, 37.5, and 50 mg of zinc and a control group of 14 individuals. Blood samples were collected over a period of 240 min after the basal samples (−30 and 0 min). We did not detect any change in plasma glucose or insulin levels, a fact that we attribute either to the ineffectiveness of the 50 mg dose of zinc or to the lack of human response to the acute action of this trace element. The individuals who ingested zinc showed a significant fall in plasma cortisol, probably caused by the action of this trace element.     

Prospective association between baseline plasma zinc concentration and development of proteinuria in Chinese hypertensive patients

ObjectiveWe aimed to evaluate the association between baseline plasma zinc and the development of proteinuria as well as possible effect modifiers in hypertensive patients.MethodsThis is a subset of the China Stroke Primary Prevention Trial (CSPPT) Renal Sub-Study. In the CSPPT, participants were randomized to receive a daily oral dose of 1 tablet containing 10 mg enalapril and 0.8 mg folic acid or 1 tablet containing 10 mg enalapril only. A total of 783 participants with plasma zinc measurements and without proteinuria at baseline were included in the current study. The study outcome was the development of proteinuria during the follow-up, defined as a urine dipstick reading of trace or ≥1+ at the exit visit.ResultsDuring a median follow-up duration of 4.4 years, the development of proteinuria occurred in 93 (11.9 %) participants. There was an inverse relation of baseline plasma zinc with the development of proteinuria (per SD increment; OR, 0.74, 95 % CI: 0.55−0.99), p for trend of quartiles = 0.005.ConclusionsIn Chinese hypertensive patients, there was a significant inverse association between baseline plasma zinc and the development of proteinuria, although plasma zinc remained in the reference range.     

Plasma status of selected minerals in hypertensive men with and without insulin resistance

The altered plasma statuses of selected minerals (Ca, Mg, Cu, Zn) have been noted in a cluster of insulin resistance syndromes, including hypertension and diabetes mellitus. The differences in plasma values of these minerals in hypertensive men with and without insulin resistance, as evaluated by an insulin suppression test, were investigated. The results showed that the plasma values of determined minerals at fasting, 2 h after an oral glucose challenge, and after the insulin suppression test did not markedly differ between hypertensive subjects with and without insulin resistance. However, hypertensive subjects had significantly lower plasma Ca values at fasting and 2h after an oral glucose load, and higher fasting plasma Zn values, than normotensive controls. Hypertensive subjects also had higher steady-state plasma glucose values, higher Zn and lower Mg and Cu values after the insulin suppression test, when compared with controls. The present study suggests that altered plasma status of selected minerals in hypertension cannot be totally ascribed to the coexhibition of insulin resistance.