Zinc levels after intravenous administration of zinc sulphate in insulin-dependent diabetes mellitus patients

Zinc Modulates Glutamine Metabolism in T Cells

SCOPE

Zinc and glutamine are well known to be essential for the function and polarization of immune cells. TH 17 cells are more frequently induced during zinc deficiency and cover their energy requirement mainly through glutaminolysis. A dysregulation of TH 17 cells can contribute to the development of autoimmune diseases. Both inhibition of glutaminolysis and zinc supplementation suppress experimental autoimmune encephalomyelitis in mice. Therefore, the aim of this study is to investigate whether zinc modulates glutaminolysis in T cells.

METHODS AND RESULTS

CD3/CD28 stimulation and mixed lymphocytes culture are used as in vitro models for T cell activation. Then, the glutaminolysis is investigated on mRNA, protein, and functional level. Zinc deficiency and glutaminase (GLS) inhibition decrease immune responses in vitro. Furthermore, extracellular zinc and glutamine levels both modulate glutaminolysis by changing the expression of glutamine transporters and key enzymes. Intriguingly, zinc directly interferes with the activity of GLS both in a cell free system and in the cytosol.

CONCLUSION

Besides T cell subset differentiation, zinc also impacts on the cellular metabolism by inhibiting glutaminolysis. This suggests that zinc deficiency can contribute to the development of autoimmune diseases whereas zinc supplementation can support their therapy.

Does infusion time affect the retention of parenteral trace elements?

When readymade parenteral nutrition in multi-chamber bags is supplied without vitamins and minerals, these have to be added or given separately. Separate rapid infusion has logistical advantages but has been claimed to saturate tissue mechanisms, potentially increasing urine micronutrient losses. The present study compared urinary losses after fast (1 h) v. slow (10 h) trace elements infusion. The study enrolled thirty-nine consecutive patients who were starting parenteral nutrition postoperatively. One day’s dose of a complete intravenous micronutrient product was infused over 1 h and over 10 h, in random order, with a washout day after each infusion day. Urinary Zn, Mn, Se, Cr, Cu and Fe losses were measured by 24-h urine collection, recorded for each infusion day and subsequent washout day. For Zn, a dose of 100 μmol was given, and total urinary loss over the next 2 d was mean 40·6 (sd 23·8) μmol after the fast (1 h) infusion v. 33·4 (sd 25·4) μmol after the slow (10 h) infusion, that is, 7 % more of the 1-d dose was lost after fast infusion (P = 0·01). For Mn, after a dose of 1000 nmol, losses were 9·8 (sd 23·9) nmol after the fast infusion v. 22·1 (sd 47·2) nmol after the slow infusion, that is, 1 % more of the 1-d dose was lost after slow infusion (P = 0·04). There were no other significant differences: after 1 μmol Se, the losses were 1·5 (sd 0·6) μmol fast v. 1·3 (sd 0·5) μmol slow; after 200 nmol Cr, 257 (sd 92) μmol fast v. 246 (sd 107) nmol slow; after 8 μmol Cu, 1·6 (sd 1·4) μmol fast v. 1·5 (sd 1·3) μmol slow; and after 20 μmol Fe, 0·6 (sd 1·1) μmol fast v. 0·8 (sd 1·6) μmol slow (P > 0·05 for all). Overall, trace element retention appears to be minimally affected by infusion time.

Zinc Status and Autoimmunity: A Systematic Review and Meta-Analysis

Zinc is an essential trace element for living organisms and their biological processes. Zinc plays a key role in more than 300 enzymes and it is involved in cell communication, proliferation, differentiation and survival. Zinc plays also a role in regulating the immune system with implications in pathologies where zinc deficiency and inflammation are observed. In order to examine the experimental evidence reported in the literature regarding zinc levels in the body of patients with autoimmune disorders compared to control individuals, a systematic review and meta-analysis were performed. From 26,095 articles identified by literature search, only 179 of them were considered potentially relevant for our study and then examined. Of the 179 articles, only 62 satisfied the inclusion criteria. Particularly for Fixed Model, Zn concentration in both serum (mean effect = −1.19; confidence interval: −1.26 to −1.11) and plasma (mean effect = −3.97; confidence interval: −4.08 to −3.87) samples of autoimmune disease patients was significantly lower than in controls. The data presented in our work, although very heterogeneous in the manner of collecting and investigating samples, have proved to be extremely consistent in witnessing a deficiency of zinc in serum and plasma of patients compared to controls.

Zinc homeostasis in the metabolic syndrome and diabetes

Zinc (Zn) is an essential mineral that is required for various cellular functions. Zn dyshomeostasis always is related to certain disorders such as metabolic syndrome, diabetes and diabetic complications. The associations of Zn with metabolic syndrome, diabetes and diabetic complications, thus, stem from the multiple roles of Zn: (1) a constructive component of many important enzymes or proteins, (2) a requirement for insulin storage and secretion, (3) a direct or indirect antioxidant action, and (4) an insulin-like action. However, whether there is a clear cause-and-effect relationship of Zn with metabolic syndrome, diabetes, or diabetic complications remains unclear. In fact, it is known that Zn deficiency is a common phenomenon in diabetic patients. Chronic low intake of Zn was associated with the increased risk of diabetes and diabetes also impairs Zn metabolism. Theoretically Zn supplementation should prevent the metabolic syndrome, diabetes, and diabetic complications; however, limited available data are not always supportive of the above notion. Therefore, this review has tried to summarize these pieces of available information, possible mechanisms by which Zn prevents the metabolic syndrome, diabetes, and diabetic complications. In the final part, what are the current issues for Zn supplementation were also discussed.

Association of reduced zinc status with angiographically severe coronary atherosclerosis: a pilot study

In vitro studies attribute antiatherogenic and insulin-like properties to zinc (Zn). However, only a few conflicting clinical data exist concerning the relationship between Zn and coronary artery disease (CAD) as well as glycemic indices. We studied 72 patients without prior history of myocardial infarction or revascularization procedures, who underwent coronary angiography for evaluation of chest pain. Coronary artery disease severity was estimated using 3 angiographic scores. Zn in serum and 24-hour urine, as well as serum Zn/24-hour urine Zn ratio were determined. Serum Zn was not associated with CAD prevalence and severity. However, urinary Zn loss was significantly higher among patients with CAD and showed a positive association with CAD severity. Serum Zn/24-hour urine Zn ratio was inversely associated with CAD, as well as with diabetes mellitus prevalence, fasting glucose, and glycated hemoglobin levels. Low serum Zn/24-hour urine Zn ratio is associated with angiographically severe atherosclerosis and impaired glucose homeostasis.

Serum magnesium and protein concentrations during the first five years of insulin-dependent diabetes in children

Thirty-four children were followed up prospectively for 5 years from the onset of diabetes regarding serum magnesium, zinc and some proteins. Serum magnesium decreased to significantly lower values (0.76 +/- 0.05 mmol l-1) than those in matched controls after 2 and 5 years, with the lowest mean values in diabetic girls. Serum zinc concentration was higher in the diabetic group than in the control children, and again the diabetic girls differed most from the controls. Serum prealbumin was significantly lower in the diabetic patients after 2 and 5 years than in the controls. Serum albumin was also slightly reduced in the diabetic patients, while orosomucoid was normal. These data indicate chronic magnesium deficiency and insufficient liver synthesis of certain serum proteins in diabetic children.

Zinc concentration in patients with iron overload receiving oral iron chelator 1,2-dimethyl-3-hydroxypyrid-4-one or desferrioxamine

AIMS

To determine the changes in serum zinc concentration and the extent of urinary zinc excretion in patients with iron overload receiving the oral iron chelator 1,2-dimethyl-3-hydroxypyrid-4-one (L1) or desferrioxamine (DFX), and to correlate these results with blood glucose concentration.

METHODS

Serum zinc and ferritin concentrations, urinary zinc and iron excretion were regularly assayed in 39 patients and the glucose tolerance test (GTT) was performed in each patient. Patients were segregated according to their GTT into normal, diabetic, and those with an abnormal GTT. The mean of L1- or DFX associated urinary zinc excretion for each group was determined and compared with the other two groups and with normal value. L1 associated urinary zinc excretion was also compared with L1 dose, serum ferritin values, and urinary iron excretion.

RESULTS

Both DFX and L1 were associated with a significantly increased urinary zinc excretion (15.1 (7.3) mumol/24 hours, 11.1 (6.0) mumol/24 hours, respectively) compared with normal subjects. In patients receiving DFX this increase only occurred in patients with diabetes mellitus. Both diabetic and non-diabetic patients receiving L1 treatment excreted more zinc than normal. Diabetic patients receiving L1 or DFX excreted more zinc than non-diabetics receiving the same treatment. No correlation was found between urinary zinc excretion and L1 dose or patients' serum ferritin concentrations. In seven patients receiving long term L1 treatment a fall in serum zinc was observed from an initial 13.6 (1.6) mumol/l to a final 9.6 (0.8) mumol/l. In one patient this was associated with symptoms of dry skin and itchy skin patches requiring treatment with oral zinc sulphate.

CONCLUSIONS

In contrast to DFX, L1 treatment is associated with increased zinc loss. This, however, is modest and does not lead in most patients to subnormal serum zinc concentrations. In a few patients whose negative zinc balance may give rise to symptoms, zinc supplementation rapidly corrects the deficit.