Decreased natural killer cell activity in patients with zinc deficiency with sickle cell disease

Zinc deficiency is associated with depression of a number of immune responses. To assess the relationship of zinc and natural killer activity, we studied natural killer activity in adults with sickle cell disease and in two normal volunteers rendered zinc deficient by dietary restriction. Natural killer activity was significantly lower in patients with sickle cell disease and zinc deficiency (5.1 +/- 2.9 lytic units per 10(6) cells) than in controls (11.7 +/- 5.0 lytic units per 10(6) cells). In the two volunteers, natural killer activity declined during zinc restriction and returned to near initial levels with zinc repletion. These results suggest that zinc deficiency is associated with a lowering of natural killer activity.

Clinical and biochemical manifestations of zinc deficiency in human subjects

During the past two decades, essentiality of zinc for man has been established. Deficiency of zinc in man attributable to nutritional factors and several diseased states has been recognized. High phytate content of cereal proteins decreases availability of zinc; thus the prevalence of zinc deficiency is likely to be high in the population subsisting mainly on cereal proteins. Zinc deficiency has been noted to occur in patients with malabsorption syndrome, chronic renal disease, cirrhosis of the liver, sickle cell disease, AE (acrodermatitis enteropathica), and other chronically debilitating diseases. Growth retardation, male hypogonadism, skin changes, poor appetite, mental lethargy, and delayed wound healing are some of the manifestations of chronically zinc-deficient human subjects. In severely zinc-deficient patients, dermatological manifestations, diarrhea, alopecia, mental disturbances, and intercurrent infections predominate. If untreated, the condition becomes fatal. Zinc deficiency affects testicular functions adversely in man and animals. This effect of zinc is at the end-organ level. It appears that zinc is essential for spermatogenesis. Zinc is involved in many biochemical functions. Several zinc metalloenzymes have been recognized in the past decade. Zinc is required for each step of cell cycle in microorganisms and is essential for DNA synthesis. The effect of zinc on protein synthesis may be attributable to its vital role in nucleic acid metabolism. The activities of many zinc-dependent enzymes have been shown to be affected adversely in zinc-deficient tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Interactions of trace elements: clinical significance

We examined interaction of the trace element zinc with copper and lead. In sickle cell anemia, the usual situation is one of mild to moderate zinc deficiency owing to renal loss of zinc. Zinc deficiency seems to produce a mild overburden of copper and an increased ceruloplasmin level, probably by enhancing copper absorption. With zinc therapy, this process is reversed. Pharmacological doses of zinc, when administered in a way to ensure effectiveness (without food) will usually lead to copper deficiency. We have taken advantage of the copper-depleting effect of zinc to design a new therapy for Wilson's disease. Zinc, by inducing intestinal metallothionein, inhibits absorption of copper from food, and inhibits reabsorption of endogenously secreted copper, thereby producing a negative copper balance in Wilson's disease. Once we are certain that zinc blocks accumulation of copper in the liver of Wilson's disease patients, zinc therapy will be available as one approach for treating this fatal disease. The animal literature indicates that zinc protects against lead toxicity when both elements are given orally, no doubt through the intestinal metallothionein mechanism. In preliminary experiments in rats, we have not been able to show that toxicity from lead that arrives into the body through a nonoral route is affected by oral zinc supplements.

Pharmacokinetics and tolerance of intravenous and intramuscular recombinant alpha 2 interferon in patients with malignancies

Fifteen patients with advanced hematopoietic and other malignancies were treated with recombinant DNA produced Alpha 2 Interferon (IFN) (Schering) by intravenous (IV) and intramuscular (IM) routes at weekly intervals in escalating doses from 1 X 10(6) IU to 100 X 10(6) IU in order to determine the tolerance and pharmacokinetics. The most common side effects included fever, chills, myalgia, and arthralgia. At doses of 60 X 10(6) or above, severe but reversible hypotension was observed in five patients receiving interferon by intravenous route. Patients receiving interferon by intramuscular route had fever, chills, and myalgias but did not develop hypotension at the same dosage. Two patients with non-Hodgkin lymphoma showed objective evidence of regression. Our data suggest a biphasic pattern of elimination with terminal half-life ranging from 1.9 to 2.9 hours and peak titer of 16,000 units and under for IV interferon, and terminal half-life of 6 hours with peak titers of 600 units for intramuscular interferon. However, interpatient variability precludes a definite conclusion. Although the areas under the serum concentration vs time curves were similar, the intravenous route provided higher but unsustained levels of interferon than the intramuscular route.

Discovery and importance of zinc in human nutrition

The present explosion in knowledge of zinc has been the result of several factors, the major ones being the recognition of the important role of zinc in human health and diseases, its vital functions in biochemical reactions, and the technological advances that make it feasible to quantitate this essential trace element in biological fluids. Deficiency of zinc in humans due to nutritional factors and several disease states has now been recognized. The high phytate content of cereal proteins is known to decrease the availability of zinc; thus, the prevalence of zinc deficiency is likely to be high in a population consuming large quantities of proteins. Alcoholism, malabsorption, sickle cell anemia, chronic renal disease, and chronically debilitating diseases are now known to be predisposing factors for zinc deficiency. A severe deficiency of zinc such as that seen in patients with acrodermatitis enteropathica may be life-threatening. A spectrum of clinical manifestations ranging from mild to severe degrees has now been recognized in human zinc deficiency states. Zinc appears to be involved in many biological functions including DNA synthesis. Roles for zinc in enzymatic functions, cell membranes, and immunity are now well established.

Zinc supplementation and growth in sickle cell disease

With the use of flameless atomic absorption spectrophotometry, we have devised a technique for measuring zinc in neutrophils. Neutrophil zinc levels in patients with sickle cell anemia correlated significantly with height and weight, and with serum testosterone in men. Such correlations were not seen with zinc levels in plasma or erythrocytes. We also report the beneficial effects of zinc supplementation on longitudinal growth and body weight in 14- to 18-year-old patients with sickle cell anemia. Thus, the neutrophil zinc level is a reliable and sensitive indicator of zinc deficiency in these patients.

Zinc metabolism and taste acuity in renal transplant recipients

To determine the effect of renal transplantation on taste acuity and zinc metabolism, we tested 43 patients with functioning allografts for 2.5 to 96 months. They were tested for taste by the 3-drop stimulus technique. In 30 of them, we determined zinc levels in plasma, hair, and urine. Subnormal plasma and hair zinc, as well as hyperzincuria, was present in all of the 15 patients less than 12 months posttransplant. In contrast, 10 patients who were more than 12 months posttransplant had plasma zinc levels, hair zinc, and urinary zinc excretions in the normal range. Zinc concentrations in plasma and hair of 5 patients who were more than 12 months posttransplant with renal failure, were subnormal and were similar to those in hemodialysis patients. Similarly, taste detection and recognition thresholds for sodium chloride, sucrose, urea, and hydrochloric acid were normal only in patients more than 12 months posttransplant with normal renal function. Plasma zinc, hair zinc, and urinary zinc were not related to prednisone or azathioprine dosage. These results suggest that abnormalities of zinc and taste persist up to 12 months posttransplant and may be related to increased urinary zinc losses.

Determination of ultrafiltrable zinc in plasma by flameless atomic absorption spectrophotometry

Ultrafiltrable zinc can be determined in small volumes of plasma by using Amicon ultrafiltration membrane cones and either flameless atomic absorption spectrophotometry or 65Zn. The ultrafiltration membrane cone is made sufficiently zinc-free by acid washing, followed by rinsing with de-ionized water. Within-run CVs were 12 and 10%, respectively, for the two methods. Matrix effects are compensated for by using standards in solutions with an inorganic matrix that simulates the sample matrix. Results for ultrafiltrable zinc by the two techniques agreed, and agreed with previously published data obtained by different ultrafiltration techniques. The mean (and SD) percentage of plasma zinc that was ultrafiltrable in 12 control subjects was 1.0 (0.5) by AAS and 0.7 (0.3) by 65Zn.

Determination of ultrafiltrable zinc in plasma by flameless atomic absorption spectrophotometry

Ultrafiltrable zinc can be determined in small volumes of plasma by using Amicon ultrafiltration membrane cones and either flameless atomic absorption spectrophotometry or 65Zn. The ultrafiltration membrane cone is made sufficiently zinc-free by acid washing, followed by rinsing with de-ionized water. Within-run CVs were 12 and 10%, respectively, for the two methods. Matrix effects are compensated for by using standards in solutions with an inorganic matrix that simulates the sample matrix. Results for ultrafiltrable zinc by the two techniques agreed, and agreed with previously published data obtained by different ultrafiltration techniques. The mean (and SD) percentage of plasma zinc that was ultrafiltrable in 12 control subjects was 1.0 (0.5) by AAS and 0.7 (0.3) by 65Zn.

The role of zinc in gastrointestinal and liver disease

Zinc is essential for many metabolic and enzymatic functions in man. Deficiency of zinc in man has now been recognized to occur not only as a result of nutritional factors, but also in various disease states, including malabsorption syndromes, acrodermatitis enteropathica, Crohn's disease, alcoholism and cirrhosis of the liver. The deficiency state in human subjects exists as a spectrum extending from mild to severe degree. The clinical manifestations of mild zinc deficiency include oligospermia, weight loss and hyperammonaemia. Moderate zinc deficiency is characterized clinically by growth retardation, hypogonadism in males, skin changes, poor appetite, mental lethargy, delayed wound healing, taste abnormalities and abnormal dark adaptation. In severe zinc deficiency states, bullous-pustular dermatitis, alopecia, diarrhoea, emotional disorders, weight loss, intercurrent infections, hypogonadism in males and, if unrecognized, death have been observed. Zinc is needed for the functions of over 100 enzymes. It is essential for DNA, RNA and protein synthesis and, as such, is important for cell division. Zinc is an inducer of mRNA of metallothionein, a protein which may have an important role in the regulation of intestinal zinc absorption. Zinc has a specific effect on testes in animals and man. Recent reports indicate that in human subjects thymopoietin may be zinc dependent and in animal studies somatomedin may be affected adversely due to dietary zinc restriction. Zinc plays an important role in the protection of cell membrane integrity and may be protective against free radical injury. Zinc is known to compete with cadmium, lead, copper, iron and calcium for similar binding sites. In the future, a potential use of zinc may be to alleviate toxic effects of cadmium and lead in human subjects. Recent evidence suggests that thymic-dependent lymphocytes (T cells are zinc dependent. T-helper and suppressor cells, T-effector cells and T-natural killer cells appear to be zinc dependent. Zinc is also essential for some of the neutrophil functions. Thus, it appears that zinc may play an important role in immunity. One may suggest that some of the clinical features of cirrhosis of the liver, such as testicular atrophy, loss of body hair, night blindness, poor wound healing, poor appetite, susceptibility to infections and enhanced sensitivity to drugs, may be related to conditioned deficiency of zinc, future studies are required to determine whether or not zinc supplementation is beneficial to these patients.

Oral zinc therapy for Wilson's disease

Wilson's disease is an inherited disorder of copper accumulation that is fatal if untreated. Because penicillamine, the established treatment, is toxic in a substantial number of patients, we studied the efficacy of zinc treatment. We induced a negative or neutral copper balance in five out of five patients with Wilson's disease who were receiving no therapy other than zinc. Zinc acetate was given every 4 hours during the day, and the patient was not allowed to eat for 1 hour before and 1 hour after each dose. Oral zinc therapy, used according to our regimen, may now be considered in the treatment of patients with penicillamine intolerance. However, it is premature to convert patients to zinc therapy if they tolerate penicillamine well. The efficacy of zinc therapy in the initial removal of the copper burden in acutely ill patients with Wilson's disease has not yet been evaluated.

Essential thrombocythemia: a clonal disorder of hematopoietic stem cell

We studied 5 patients with essential thrombocythemia utilizing glucose-6-phosphate dehydrogenase (G-6-PD) enzyme as a cell marker for determining clonality. One of the patients was found to be heterozygous for isoenzymes B and A in the nonhaemopoietic tissues such as fibroblasts, but manifested only isoenzyme type B in the erythrocytes, neutrophils, and platelets. Our studies support the concept that essential thrombocythemia is a clonal disorder arising in a multipotent stem cell.

Anergy, zinc deficiency, and decreased nucleoside phosphorylase activity in patients with sickle cell anemia

Cell-mediated immunity was evaluated in 26 patients with sickle cell anemia using skin tests for delayed hypersensitivity reactions. Patients with impaired delayed hypersensitivity reactions had lower zinc levels in plasma, erythrocytes, and neutrophils than patients with normal delayed hypersensitivity reactions or controls. The activity of nucleoside phosphorylase, an enzyme essential for T-lymphocyte function, was significantly lower in zinc-deficient patients with anergic sickle cell anemia. We conclude that zinc deficiency in patients with sickle cell anemia is associated with impaired delayed hypersensitivity. Decreased activity of nucleoside phosphorylase may be partially responsible for lymphocyte dysfunction in these patients.

Zinc deficiency: a reversible complication of uremia

Subnormal plasma zinc levels and decreased zinc concentration in hair and leucocytes as well as increased plasma ammonia and ribonuclease activity in dialyzed and nondialyzed uremic patients indicate that zinc metabolism is abnormal in uremia and is not corrected by dialysis. The effect of oral supplementation with zinc acetate (12 patients) or placebo (12 patients) on the above biochemical parameters in hemodialysis patients was determined as a part of a double-blind study. The zinc-supplemented, but not the placebo, group demonstrated significant increases in mean (+/- SD), plasma zinc (80 +/- 9 to 110 +/- 14, micrograms/dl), leucocyte zinc (56 +/- 13 to 1098 +/- 18, micrograms/10(10) cells), hair zinc (140 +/- 12 to 190 +/- 16 micrograms/g), and decreases in plasma ammonia (76 +/- 10 to 40 +/- 6 micrograms/dl) and plasma ribonuclease activity (1.49 +/- 0.08 to 0.78 +/- 0.10, OD/min/ml). Abnormalities of taste and sexual function improved significantly in patients receiving zinc but not in those on placebo therapy. These improvements in biochemical as well as clinical parameters confirm and extend our earlier observations of improvement in taste and sexual function after zinc supplementation. Together, they suggest that zinc deficiency is a complicating feature of uremia and can be corrected by oral zinc supplementation.

Effect of oral zinc therapy on gonadal function in hemodialysis patients. A double-blind study

Zinc deficiency may account for the persistence of gonadal dysfunction in a majority of uremic men despite adequate dialysis. Twenty stable patients having hemodialysis three times a week completed a double-blind trial using either 50 mg of elemental zinc as zinc acetate (10 patients) or placebo (10 patients), orally. At the end of the 6-month study period, a significant increase in the mean (+/- SE) plasma zinc (75 +/- 2 micrograms/dL to 100 +/- 2 micrograms/dL, p less than 0.001), serum testosterone (2.8 +/- 0.3 ng/dL to 5.2 +/- 0.5 ng/mL, p less than 0.001), and sperm count (30 +/- 3 million/mL to 63 +/- 5 million/mL, p less than 0.001) occurred in the zinc-treated group, but not in those receiving the placebo. The zinc-treated group also had a significant fall in serum luteinizing hormone (92 +2- 10 mIU/mL to 49 +/- 26 mIU/mL, p less than 0.005) and follicle stimulating hormone (45 +/- 9 mIU/mL to 25 +/- 7 mIU/mL, p less than 0.05), not seen in the placebo group. Patients receiving zinc had an improvement in potency, libido, and frequency of intercourse not found in the placebo group. These results suggest that zinc deficiency is a reversible cause of gonadal dysfunction in patients having regular hemodialysis.

Lymphocyte and granulocyte function in zinc-treated and zinc-deficient hemodialysis patients

Lymphocyte blast transformation and granulocyte motility were studied in 20 clinically stable hemodialysis patients, 10 of whom were receiving 50 mg of zinc (as zinc acetate) per day and 10 of whom were not. Plasma zinc concentration was significantly higher in zinc-treated than in untreated patients (108 +/- 5 vs. 82 +/- 2 micrograms/dl). Mononuclear cell subpopulation analysis showed equivalent proportions of T lymphocytes and monocytes in both groups, but B lymphocytes were reduced in untreated patients (10 +/- 0.7 vs 14 +/- 0.5%). Lymphocyte blast transformations in response to nonspecific mitogens, soluble antigen and mixed lymphocyte culture were not significantly different in the two groups, nor was lymphocyte zinc concentration. Zinc-treated patients showed significantly greater granulocyte responsiveness to zymosan-activated serum (21 +/- 1 vs. 14 +/- 2 mean), greater chemokinetic activity (50 +/- 4 vs. 27 +/- 3 mean) and higher granulocyte zinc concentration (114 +/- 6 vs. 47 +/- 2 micrograms/10(6) cells) than untreated patients. Granulocyte zinc correlated significantly with plasma zinc (r = 0.81, P less than 0.001) and with granulocyte motility (r = 0.63, P = 0.001). Moderate zinc deficiency in hemodialysis patients does not result in abnormal lymphocyte blast transformation in vitro, but it does result in granulocyte zinc depletion and impaired granulocyte motility.

Long survival in sickle cell anemia

Ten patients with sickle cell anemia surviving beyond the age of 40 were compared to 11 subjects with sickle cell anemia who died before that age. Hematologic and biochemical data as well as clinical and physical parameters of the two groups were compared. There was no statistically significant difference between the two groups with respect to the degree of anemia, severity of hemolysis, or hemoglobin A2 levels. A statistically significant difference was found between the two groups with respect to fetal hemoglobin, red cell zinc, and secondary sexual characteristics. Although the long survivors had fewer crises per year than the short survivors, the long-term complications such as leg ulcer, congestive heart failure, and aseptic necrosis of the hip were more common in the older patients. Cerebrovascular accidents were the cause of death in 9/11 short survivors and are absent in the long survivors. The alpha/beta chain synthesis ratio was normal in the long-survivor group and alpha gene mapping in five subject in that group revealed the genotype alpha alpha/alpha alpha in four and -alpha/alpha alpha in one. The older patients as a group had higher red cell zinc values. The secondary sexual characteristics were also better developed in the older subjects. The overall significance of zinc status and of a higher HbF on longevity of sickle cell anemia patients remains unknown.

Zinc in plasma, neutrophils, lymphocytes, and erythrocytes as determined by flameless atomic absorption spectrophotometry

Zinc is determined in neutrophils and lymphocytes (isolated from whole blood on discontinuous gradients of Ficoll-Hypaque) and in microliter quantities of plasma and erythrocytes by flameless atomic absorption spectrophotometry with greater sensitivity than with conventional flame atomic absorption spectrophotometry. Before analysis, neutrophils and lymphocytes are digested with nitric acid and diluted with de-ionized water. Plasma and erythrocytes required no digestion, only dilution. Overall CVs were 4.0, 3.0, 5.0, and 4.6% for neutrophils, lymphocytes, erythrocytes, and plasma, respectively. Matrix effects were fully compensated for by use of standard solutions that simulated the sample matrix. Results for plasma and erythrocytes agreed with those obtained by the conventional technique.