Trace element alterations in infectious diseases

Assessment of trace elements in critically ill patients with systemic inflammatory response syndrome: A systematic review

BACKGROUND

Zinc (Zn), copper (Cu), and selenium (Se) are involved in immune and antioxidant defense. Their role in systemic inflammatory response syndrome (SIRS) treatment and outcomes remains unclear. This systematic review aimed to describe trace element concentrations in different types of biological samples and their relationship with morbidity and mortality in patients with SIRS.

METHODS

Literature was systematically reviewed according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA). The search results were screened and evaluated for eligibility, and data were extracted and summarized in tables and figures.

RESULTS

Most of the 38 included studies evaluated Se (75%), followed by Zn (42%) and Cu (22%). Plasma was the main biological sample evaluated (58%). Thirteen studies found lower plasma/serum concentrations of Zn, Se, and Cu in SIRS patients than in controls upon admission, 11 studies on adults (intensive care unit-ICU) and two in pediatric ICU (PICU). Three ICU studies found no difference in erythrocyte trace element concentrations in patients with SIRS. In all studies, the two main outcomes investigated were organ failure and mortality. In seven ICU studies, patients with lower plasma or serum Zn/Se levels had higher mortality rates. A study conducted in the PICU reported an association between increased Se variation and lower 28-day mortality. In an ICU study, lower erythrocyte selenium levels were associated with higher ICU/hospital mortality, after adjustment. Five ICU studies associated lower plasma/serum Zn/Se levels with higher organ failure scores and one PICU study showed an association between higher erythrocyte Se levels and lower organ dysfunction scores.

CONCLUSION

There was no difference in erythrocyte Se levels in patients with SIRS. Serum/Plasma Zn and serum/plasma/erythrocyte Se are associated with organ dysfunction, mortality, and inflammation. Trace element deficiencies should be diagnosed by erythrocyte, or complementary measurements in the presence of inflammation.

“Anosmia” the mysterious collateral damage of COVID-19

COVID-19 pandemic spreads worldwide, with more than 100 million positive cases and more than 2 million deaths. From the beginning of the COVID-19 pandemic, several otolaryngologists described many cases of a sudden loss of smell (anosmia) associated with the disease with or without additional symptoms. Anosmia is often the first and sometimes the only sign in the asymptomatic carriers of COVID-19. Still, this disorder is underestimated, and it is not life-threatening. However, it significantly decreases the quality of life. This olfactory dysfunction continues in several cases even after the nasopharyngeal swab was negative. The occurrence of anosmia can be used as a screening tool for COVID-19 patients and can be used to identify these patients to accomplish the isolation and tracking procedures. In this review, we highlighted the possible mechanisms of anosmia in COVID-19 patients, major pathologies and features of anosmia, implications of anosmia in early diagnosis of COVID-19, evaluation of the smell function during COVID-19, and management and treatment options of COVID-19 anosmia.

Intra-nasal zinc level relationship to COVID-19 anosmia and type 1 interferon response: A proposal

Anosmia is common among COVID-19 patients and anosmia assessment is proposed to be useful in the early diagnosis and prognosis of patients. Data on the pathogenesis of anosmia during COVID-19 suggest potential olfactory nerve involvement. Zinc is an essential micronutrient that regulates the immune responses, and zinc deficiency is known to induce anosmia and ageusia. We previously proposed that a drop in nasal zinc level is a normal nasal immune response to acute viral infections, including SARS-CoV-2 infection, and play a role in the pathogenesis of anosmia. The drop in the local zinc level in response to SARS-CoV-2 may lead to lower type 1 interferons and shift toward Th2 immune responses; if prolonged, it may lead to increased viral replication and more severe disease. In people who are at risk for baseline systemic zinc deficiency, such as the elderly and those with chronic diseases such as, chronic lung disease, diabetes, cardiovascular disease, and cancer, SARS-CoV-2 infection-induced drop in nasal zinc level may be more severe and prolonged and lead to an insufficient anti-viral nasal immune response and control the spread of the virus systemically and to the lungs. A better understanding of the clinical implications of baseline systemic zinc deficiency on anosmia and nasal immune responses may allow the development of new treatment strategies to slow down or stop the systemic invasion of SARS-CoV-2.

Pretreatment of simvastatin on liver trace element levels during endotoxemia

There are a number of studies investigating anti-inflammatory effects of simvastatin in patients with sepsis and animal models. There are a few studies which investigated effect of simvastatin on elements in sepsis. In the present study, the impact of pretreatment with simvastatin on element levels was evaluated in liver during endotoxemia. Rats were divided into control, LPS, simvastatin, and simvastatin + LPS. The histopathologic examination of the liver was performed using hematoxylin and eosin. Selenium, zinc, iron, manganese, magnesium, and copper were analyzed using inductively coupled plasma - optical emission spectroscopy. In the LPS, the hepatocyte cell structure was damaged. In the simvastatin + LPS, hepatocyte, and sinusoidal cord damage were partially smaller than LPS. Levels of selenium, and copper significantly decreased in both of LPS and simvastatin + LPS. In the LPS group, iron was found to increase. In the simvastatin + LPS, zinc was increased. Simvastatin partially smaller liver damage by increasing zinc levels during endotoxemia.

The Alterations of Copper and Zinc Homeostasis in Acute Appendicitis and the Clinical Significance

Copper (Cu) and zinc (Zn) are involved in inflammatory process. This study was to investigate the clinical significance of Cu and Zn homeostasis alterations in acute appendicitis (AA). One hundred twenty-two AA patients and 102 healthy controls were enrolled in this study. Of which, 85 patients' appendixes were collected after appendectomy. Another six appendixes from colon cancer patients were collected as tissue controls. The contents of Cu and Zn in serum or appendix were detected, and the Cu to Zn ratio (CZr) was calculated. The concentrations of serum ceruloplasmin (CP), Cu/Zn superoxide dismutase (SOD1), interleukin-6 (IL-6), and interleukin-22 in serum were measured, as well as the activity of CP and SOD1. The serum Zn concentration and SOD1 activity, appendix contents of Cu and Zn significantly decreased in AA patients, compared with those of controls, while serum CZr, concentrations of CP, SOD1, and IL-6, as well as CP activity increased significantly in AA patients. Additionally, serum concentrations of Zn, CP, CZr, or SOD1 activity varied in different pathological types of AA. Indicators such as serum SOD1 activity might serve as predictors for pathological classification before surgery. The serum Zn and CZr may be helpful for diagnosis of pure AA. The Cu and Zn homeostasis was altered in AA patients, which might contribute to inflammatory process of AA.

Particle induced X-ray emission study of blood samples of Indian Kala-azar patients

Visceral leishmaniasis (VL) or Kala-azar (KA) is a neglected tropical disease caused by protozoan parasite, Leishmania sp. and is fatal, if left untreated. In this study, we measured trace elements (K, Fe, Cu, Zn, Br, Cl, S, Ca, Mn, Cr, Ni, As, Se, Rb and Sr) in the blood of Indian VL patients (32) by particle-induced X-ray emission (PIXE) study. Blood was collected from 36 subjects including healthy controls from Rambagh Kala-azar Hospital, Muzaffarpur, Bihar, India. PIXE experiment was carried out at the Institute of Physics, Bhubaneswar, India and data were analyzed by GUPIXWIN software. We observed first time the association of bromine with the disease. The results showed 48.47 % decrease in Br, 35.16 % decrease in Zn and 29.05 % decrease in Fe in untreated state of the KA patients. In the same group, Cu has been increased by 16.73 %. Cu/Zn ratio has been altered in diseased state. The association of bromine with the disease is reported for the first time and altered levels of trace elements (Br, Cu, Fe and Zn) may come back to normal after completion of the treatment regimen with Amphotericin B.

Copper tolerance and virulence in bacteria

Copper (Cu) is an essential trace element for all aerobic organisms. It functions as a cofactor in enzymes that catalyze a wide variety of redox reactions due to its ability to cycle between two oxidation states, Cu(I) and Cu(II). This same redox property of copper has the potential to cause toxicity if copper homeostasis is not maintained. Studies suggest that the toxic properties of copper are harnessed by the innate immune system of the host to kill bacteria. To counter such defenses, bacteria rely on copper tolerance genes for virulence within the host. These discoveries suggest bacterial copper intoxication is a component of host nutritional immunity, thus expanding our knowledge of the roles of copper in biology. This review summarizes our current understanding of copper tolerance in bacteria, and the extent to which these pathways contribute to bacterial virulence within the host.

Meta-analysis of Zn, Cu and Fe in the hair of Chinese children with recurrent respiratory tract infection

Trace elements play an important role in maintaining the normal metabolic and immune function. The onset of recurrent respiratory tract infection (RRI) is associated with the immune function, genetic factors and nutritional status. However, the association between the levels of trace elements and RRI remains inconclusive. We aimed to investigate the alterations of hair levels of zinc (Zn), copper (Cu) and iron (Fe) in Chinese children with RRI by performing a meta-analysis. A predefined electronic databases search was performed to identify eligible studies for the analysis of hair Zn, Cu or Fe levels in Chinese children with RRI. Thirteen studies were included. RRI patients displayed significantly lower levels of hair Zn (13 studies, random effects SMD: - 1.215, 95% CI: - 1.704 to - 0.725, p < 0.0001), Cu (11 studies, random effects SMD: - 0.384, 95% CI: - 0.717 to - 0.052, p = 0.023) and Fe (12 studies, random effects SMD: - 0.569, 95% CI: - 0.827 to - 0.312, p < 0.0001) compared with controls. No evidence of publication bias was observed. Sensitivity analysis did not change the results significantly. In conclusion, the deficiency of Zn, Cu and Fe may be contributing factors for the susceptibility of RRI in Chinese children. However, more studies in different ethnicities should be performed in the future.

Selenium and leptin levels in febrile seizure: a case-control study in children

PURPOSE

Febrile seizures (FS) are seizures that occur between the age of 6 and 60 months, but its pathophysiology still is not fully understood. There is limited information about the correlation between levels of selenium and leptin with FS. This study aimed to determine the relationship between serum levels of selenium and leptin in children with FS.

METHODS

This case-control study was conducted in a University Hospital in Shahrekord, Iran, in 2011. The serum levels of selenium and leptin of 25 children with simple febrile seizure (case group) were compared with 25 febrile children without seizure (control group) in acute phase and after three months. The levels of serum selenium and leptin were measured by flame atomic absorption spectrophotometer and enzyme-linked immunosorbent assay method, respectively.

RESULTS

In acute phase, the mean serum level of selenium in case and control groups were 95.88±42.55 and 113.25±54.43 µg/dL, respectively, and difference was not significant (P=0.415), but after three months, this level had a significant increase in both groups (P<0.001). In acute phase, the mean serum leptin level in case and control groups were 0.94±0.5 and 0.98±0.84 ng/mL, respectively, but difference was not significant (P=0.405). After three months, serum leptin level had no significant change in both groups (P=0.882).

CONCLUSION

These observations suggest that serum levels of selenium and leptin have not specific relation with FS but overllay is lower, however, further study is recommended. Also selenium level in stress and acute phase was significantly lower than recovery phase.

Heme iron-based dietary intervention for improvement of iron status in young women

OBJECTIVE

Conventional iron deficiency treatment with pharmacologic iron doses often causes side effects. Heme iron has high bioavailability and a low capacity to cause gastrointestinal side effects. This study investigated the possibility of using heme iron in the form of blood-based crisp bread as a diet-based treatment program to improve the iron status of women of reproductive age.

METHODS

In a 12-wk intervention study, 77 women (mean age 24 y) were assigned to one of four groups: blood-based crisp bread (35 mg of iron [Fe], 27 mg of which was heme Fe), iron supplementation consisting of 35 mg of non-heme iron/day (Fe35), iron supplementation consisting of 60 mg of non-heme iron/day (Fe60), and controls (iron-free tablets).

RESULTS

Body iron increased significantly in the crisp bread group by a median of 2.7 mg/kg (interquartile range 3.1, n = 18), in the Fe35 group by 2.7 mg/kg (interquartile range 2.8, n = 11), and in the Fe60 group by 4.1 mg/kg (interquartile range 3.6, n = 13), whereas no change was observed in the control group. No statistically significant difference in iron status increase was observed between the crisp bread group compared with the two iron-supplemented groups.

CONCLUSION

Dietary-based treatment containing heme iron has few side effects and can be used efficiently to improve the iron status of women of reproductive age.

Copper homeostasis at the host-pathogen interface

The trace element copper is indispensable for all aerobic life forms. Its ability to cycle between two oxidation states, Cu(1+) and Cu(2+), has been harnessed by a wide array of metalloenzymes that catalyze electron transfer reactions. The metabolic needs for copper are sustained by a complex series of transporters and carrier proteins that regulate its intracellular accumulation and distribution in both pathogenic microbes and their animal hosts. However, copper is also potentially toxic due in part to its ability to generate reactive oxygen species. Recent studies suggest that the macrophage phagosome accumulates copper during bacterial infection, which may constitute an important mechanism of killing. Bacterial countermeasures include the up-regulation of copper export and detoxification genes during infection, which studies suggest are important determinants of virulence. In this minireview, we summarize recent developments that suggest an emerging role for copper as an unexpected component in determining the outcome of host-pathogen interactions.

A comparison of zinc metabolism, inflammation, and disease severity in critically ill infected and noninfected adults early after intensive care unit admission

BACKGROUND

Zinc deficiency is a cause of immune dysfunction and infection. Previous human studies have shown that the activation of the acute phase response alters zinc metabolism. Whether the alteration in zinc metabolism is predictive of disease severity in the setting of critical illness is unclear.

OBJECTIVE

We sought to determine whether differences occur in zinc metabolism at the onset of critical illness between infected (septic) and noninfected subjects.

DESIGN

We conducted this prospective study in an adult medical intensive care unit (MICU) at a tertiary care hospital. Subjects were enrolled within 24 h of intensive care unit admission. Subjects who did not meet sepsis criteria were considered for the critically ill control (CIC) arm. After patient consent, blood was immediately collected to measure plasma zinc and cytokine concentrations and zinc transporter gene expression in peripheral blood monocytes. Clinical data during the MICU stay were also recorded.

RESULTS

A total of 56 patients were evaluated (22 septic, 22 CIC, and 12 healthy subjects). Plasma zinc concentrations were below normal in CIC patients and further reduced in the septic cohort (57.2 ± 18.2 compared with 45.5 ± 18.1 μg/dL). Cytokine concentrations increased with decreasing plasma zinc concentrations (P = 0.05). SLC39A8 gene expression was highest in patients with the lowest plasma zinc concentrations and the highest severity of illness.

CONCLUSIONS

The alteration of zinc metabolism was more pronounced in septic patients than in noninfected critically ill patients. Specifically, sepsis was associated with lower plasma zinc concentrations and higher SLC39A8 mRNA expression, which correlated with an increased severity of illness, including cardiovascular dysfunction.

The added benefit of zinc supplementation after zinc treatment of acute childhood diarrhoea: a randomized, double-blind field trial

OBJECTIVES

To determine whether continuing with zinc supplementation after zinc treatment (ZT) of an acute diarrhoea episode will result in additional clinical benefits beyond ZT alone.

METHODS

Children 6-23 months of age, living in an urban slum in Dhaka, Bangladesh with acute childhood diarrhoea (ACD), were enrolled in a randomized, double-blind field trial. All children received 10 days of ZT (20 mg/day) and were then randomized to zinc (10 mg/day) or placebo supplementation for 3 months. Weekly follow-up of all children occurred over a period of 9 months.

RESULTS

A total of 353 subjects were enrolled, with 93% of the zinc supplemented and 96% of the placebo children followed for 9 months. The incidence density of ACD among those receiving zinc supplementation compared to those receiving placebo was reduced by 28% (2.64 vs.3.66 episodes/p-y follow-up) over the 3 months while on supplementation and by 21% (2.05 vs.2.59 episodes/p-y follow-up) over the 9 months of follow-up. There was no observed effect on the incidence of acute respiratory infections (ARIs) or on growth.

CONCLUSIONS

Zinc supplementation after treatment provides additional preventive ACD benefits to children in early childhood. Larger, effectiveness trials of this strategy are warranted.

A role for the ATP7A copper-transporting ATPase in macrophage bactericidal activity

Copper is an essential micronutrient that is necessary for healthy immune function. This requirement is underscored by an increased susceptibility to bacterial infection in copper-deficient animals; however, a molecular understanding of its importance in immune defense is unknown. In this study, we investigated the effect of proinflammatory agents on copper homeostasis in RAW264.7 macrophages. Interferon-gamma was found to increase expression of the high affinity copper importer, CTR1, and stimulate copper uptake. This was accompanied by copper-stimulated trafficking of the ATP7A copper exporter from the Golgi to vesicles that partially overlapped with phagosomal compartments. Silencing of ATP7A expression attenuated bacterial killing, suggesting a role for ATP7A-dependent copper transport in the bactericidal activity of macrophages. Significantly, a copper-sensitive mutant of Escherichia coli lacking the CopA copper-transporting ATPase was hypersensitive to killing by RAW264.7 macrophages, and this phenotype was dependent on ATP7A expression. Collectively, these data suggest that copper-transporting ATPases, CopA and ATP7A, in both bacteria and macrophage are unique determinants of bacteria survival and identify an unexpected role for copper at the host-pathogen interface.

The descrease of the in vitro proliferative response of zinc-treated stressed mice's thymic lymphocytes

Prolonged stimulation of newborn mice by intraperitoneal injections with inactivated staphylococci induces a chronic neonatal inflammatory reaction and an associated oxidative-stress response. The chronically stimulated animals exhibit anorexy. show a reduction in their body weight and undergo a depression in both antibody synthesis andin vitro proliferativc response of Con A-stimulated splenic T-lymphocytes. These stressed animals also develop adrenal hyperplasia, hypozincamia and thymic hypoplasia. Despite this stress-mediated thymic involution, Con-A stimulated T-lymphocytes from thymus displayed increased theirin vitro proliferative response. Results of the present work show that intramuscular injections of zinc acetate in stressed mice, one single dose (5 microg) every other day for two weeks, reduce both the zinc concentration in the thymus gland and thein vitro proliferative response of their Con A-stimulated T-lymphocytes. The results suggest that prophylactic administration of zinc can have benefical consequences on the immunity of chronically stressed mice.

Trace micro-nutrients may affect susceptibility to bovine tuberculosis in cattle

Bovine tuberculosis (bTB) is a continuing problem in British herds. Micro-nutrients are important for the maintenance of well-functioning immune system. The aim of this study was to determine whether the selenium, copper and vitamin B12 status of cattle was associated with Mycobacterium bovis (M. bovis) infection. Between 2002 and 2005, 200 cattle (43% dairy, mean age 4.6 years), reactors according to the standard interpretation of the tuberculin test, and 200 in-contacts (41% dairy, mean age 4.4 years) non-reactors, which had been in contact with cattle with bTB, were selected from herds in England and Wales. Levels of the seleno enzyme glutathione peroxidase (GSHPx), copper and vitamin B12 were measured in blood. Confirmation of bTB infection was made by bacteriological culture and histopathology following a detailed postmortem. Levels of selenium and copper were also measured in a random sample of 63 livers. bTB was confirmed by culture/histology in 23/200 (11.5%) of in-contacts and 110/200 (55%) of reactors. In blood drawn at recruitment, GSHPx was lower in cattle with confirmed bTB compared to other cattle (geometric means 59.7 u/mL versus 78.9 u/mL red blood cells (RBC), p<0.01). Vitamin B12 was similar (geometric means 161.5 pmol/L versus 165.5 pmol/L, p=0.62) and copper was similar (geometric means 14.4 micromol/L versus 14.1 micromol/L, p=0.55). In logistic regression models including all micro-nutrients simultaneously and controlling for age, sex, animal production class, herd size, number of reactors, postmortem laboratory and seasonal trends, lower levels of GSHPx (adjusted OR 0.42, 95% CI 0.21-0.81 per 100 u/mL RBC, p=0.01) and higher levels of copper (adjusted OR 1.69, 95% CI 1.21-2.36 per 5 micromol/L, p<0.01) were associated with an increased risk of confirmed bTB but there was no association with vitamin B12. There was evidence for a stronger association between confirmed bTB and GSHPx in in-contacts (adjusted OR 0.21, 95% CI 0.06-0.79 per 100 u/mL RBC) compared to reactors (adjusted OR 0.50, 95% CI 0.21-1.23 per 100 u/mL RBC) (p=0.08 for interaction). Lower liver copper was associated with a higher risk of confirmed bTB (adjusted OR 0.15, 95% CI 0.02-1.0 per 5,000 micromol/kgdry mass, p=0.05) but there was no association between liver selenium and bTB. Trace micro-nutrient status may affect susceptibility to M. bovis infection in cattle. Further studies are needed.

Serum zinc and copper status in hospitalized vs. healthy elderly subjects

OBJECTIVE

To assess serum zinc and copper concentrations of elderly hospitalized patients with a broad range of diseases and compare their levels to those of healthy community dwelling controls of similar age.

METHODS

This case-control study compared serum zinc and copper levels of 668 hospitalized subjects, aged 70 or over, with 104 healthy controls of the same age and from the same geographical area. The study protocol, conducted by one physician on the day after the admission to the hospital, included a questionnaire on sociodemographic characteristics, a medical examination, and serum zinc and copper measured with flame atomic absorption spectrophotometry. Data were analysed using analysis of covariance, controlling for age and sex.

RESULTS

The diseased subjects had markedly lower zinc concentrations than the control group. The frequency of low values (<0.70 mg/L) was high (20.2% vs. zero in controls, p < 0.001), and it differed among various disease categories: 35.7% for respiratory disease, 20%- 27% for cancer, infectious disease, trauma, blood diseases, and genitourinary diseases, and less than 20% for the other diseases. Low values for serum copper concentration (<0.80 mg/L) were rare in hospitalized subjects (1.4% vs. zero in controls). Whatever the disease category and number of diagnoses considered, the serum copper/zinc ratio was significantly (p < 0.001) higher in diseased than in healthy people.

CONCLUSIONS

Elderly hospitalized patients are at elevated risk of low zinc but not copper values. The significantly lower values of serum zinc found in the hospitalized elderly compared to healthy elderly are likely to be related to disease rather than to aging per se. In addition to other classic anthropometric (BMI) and biological (serum proteins) nutritional parameters, copper/zinc ratio may be a useful marker of malnutrition.

Effect of dietary phytic acid on zinc absorption in the healthy elderly, as assessed by serum concentration curve tests

Zn absorption was investigated in healthy elderly subjects aged 71–78 years and in young subjects aged 23–43 years using serum concentration curve (SCC) tests. Both groups had similar Zn and protein status. The increase in serum Zn was monitored for 180 min after ingestion of 200ml of soya milk enriched with 50mg of Zn. Three levels of phytic acid were used: 0g/200ml (totally dephytinized soya milk), 0.13 g/200ml (half dephytinized), and 0.26 g/200ml (natural phytic acid content). In a first study the effect of 0v.0.26 g/200 ml phytic acid was compared in 10 elderly and 10 young subjects, each subject receiving both treatments. In a second study soya milks with 0 and 0.13 g/200ml were tested in nine elderly and ten young subjects, again receiving both treatments. Mean areas under the curve of the SCC tests conducted with the 0 g/200 ml soya milk were found to be the same in both studies. Phytic acid strongly depressed Zn absorption in both studies (P≤ 0.05), but to a greater extent at the 0.26 g/200ml level. No difference was found between the groups of young and elderly subjects. Therefore, no significant effect of aging on Zn absorption, as evaluated by the SCC test, or on the inhibitory effect of phytic acid was detected.

Practicalities of selenium supplementation in critically ill patients

PURPOSE OF REVIEW

To review the reason for and clinical effects of selenium supplementation in critically ill patients.

RECENT FINDINGS

Selenium-dependent enzymes and selenoprotein P regulate immune and endothelial cell function. Obviously not the anorganic compounds of selenium but the activity of selenium-dependent enzymes is the most important factor modulating the immune system and the clinical outcome of patients. Despite low selenium levels in severely ill patients and low glutathione peroxidase activity associated with the extent of multiorgan dysfunction, only a few trials have investigated the effect of selenium supplementation on clinical outcome. A metaanalysis did not reveal a statistically significant survival rate with selenium supplementation, but suggested a dose-dependent trend. The recently completed multicentre trial on high-dose selenium supplementation in septic patients also did not reveal a significant overall reduction in mortality.

SUMMARY

The available evidence suggests that selenoproteins play an important role in the immunomodulation of critically ill patients and a sodium selenite supplementation upregulates these selenoenzymes. The intervention trials with sodium selenite performed to date are small and therefore only a tendency in reduction of morbidity and mortality could be demonstrated. Larger trials are necessary to show the supposed benefits and risks of selenite supplementation in critically ill patients.

Zinc and vitamin A supplementation in Indigenous Australian children hospitalised with lower respiratory tract infection: a randomised controlled trial

OBJECTIVE

To evaluate the efficacy of supplementation with zinc and vitamin A in Indigenous children hospitalised with acute lower respiratory infection (ALRI).

DESIGN

Randomised controlled, 2-by-2 factorial trial of supplementation with zinc and vitamin A.

SETTING AND PARTICIPANTS

187 Indigenous children aged < 11 years hospitalised with 215 ALRI episodes at Alice Springs Hospital (April 2001 to July 2002).

INTERVENTIONS

Vitamin A was administered on Days 1 and 5 of admission at a dose of 50 000 IU (infants under 12 months), or 100 000 IU; and zinc sulfate was administered daily for 5 days at a daily dose of 20 mg (infants under 12 months) or 40 mg.

MAIN OUTCOME MEASURE

Time to clinical recovery from fever and tachypnoea, duration of hospitalisation, and readmission for ALRI within 120 days.

RESULTS

There was no clinical benefit of supplementation with vitamin A, zinc or the two combined, with no significant difference between zinc and no-zinc, vitamin A and no-vitamin A or zinc + vitamin A and placebo groups in time to resolution of fever or tachypnoea, or duration of hospitalisation. Instead, we found increased morbidity; children given zinc had increased risk of readmission for ALRI within 120 days (relative risk, 2.4; 95% CI, 1.003-6.1).

CONCLUSION

This study does not support the use of vitamin A or zinc supplementation in the management of ALRI requiring hospitalisation in Indigenous children living in remote areas. Even in populations with high rates of ALRI and poor living conditions, vitamin A and zinc therapy may not be useful. The effect of supplementation may depend on the prevalence of deficiency of these micronutrients in the population.

Lower serum zinc in Chronic Fatigue Syndrome (CFS): relationships to immune dysfunctions and relevance for the oxidative stress status in CFS

The present study examines serum zinc concentrations in patients with chronic fatigue syndrome (CFS) versus normal volunteers. Serum zinc levels were determined by means of an atomic absorption method. We found that serum zinc was significantly lower in the CFS patients than in the normal controls. There was a trend toward a significant negative correlation between serum zinc and the severity of CFS and there was a significant and negative correlation between serum zinc and the subjective experience of infection. We found that serum zinc was significantly and negatively correlated to the increase in the alpha2 protein fraction and positively correlated to decreases in the expression of mitogen-induced CD69+ (a T cell activation marker) on CD3+ as well as CD3+CD8+ T cells. These results show that CFS is accompanied by a low serum zinc status and that the latter is related to signs of inflammation and defects in early T cell activation pathways. Since zinc is a strong anti-oxidant, the present results further support the findings that CFS is accompanied by increased oxidative stress. The results of these reports suggest that some patients with CFS should be treated with specific antioxidants, including zinc supplements.

A clinical review of micronutrients in HIV infection

This article reviews current literature on the role of micronutrients in human immunodeficiency virus (HIV) infection. Deficiencies of micronutrients are common in HIV-infected persons. They occur due to malabsorption, altered metabolism, gut infection, and altered gut barrier function. There is a compelling association of deficiencies of micronutrients in HIV-infection with immune deficiency, rapid disease progression, and mortality. Also, there is increased risk of vertical HIV transmission from mother to child with deficiency of vitamin A, and of neurological impairment with vitamin B12. The last five years have been exciting in micronutrient research, and there is promise that some micronutrients may be key factors in maintaining health in HIV immunodeficiency, and in reducing mortality. Selenium appears important in reducing virulence of HIV and slowing disease progression. Vitamin A supplementation in pregnant women with HIV may reduce maternal mortality and improve birth outcomes. Supplementation in children with HIV may accelerate growth. Carotenoid supplementation is being evaluated. Vitamin B12 may slow HIV immune deficiency disease progression, and reverse neurological compromise. Clinical benefit of supplementation with some micronutrients may be measurable in the presence of pre-existing deficiency. Apart from improved general nutrition, the impact of micronutrient supplements on health and their optimal use in HIV infection is controversial because there are so few controlled clinical trials. Further research is needed to elucidate the role of micronutrient deficiencies on the course of HIV infection, and the preventive and therapeutic role of supplementation in its clinical management. Nevertheless, current knowledge supports the use of routine multivitamin and trace element supplementation as adjuvant to conventional antiretroviral drug treatment as a relatively low-cost intervention.

Putative biomarkers for evaluating antibiotic treatment: an experimental model of porcine Actinobacillus pleuropneumoniae infection

Biomarkers of infection were screened for their possible role as evaluators of antibiotic treatment in an aerosol infection model of porcine pneumonia caused by Actinobacillus pleuropneumoniae (Ap). Following infection of 12 pigs, clinical signs of pneumonia developed within 20 h, whereafter the animals received a single dose of either danofloxacin (2.5mg/kg) or tiamulin (10 mg/kg). To test the discriminative properties of the biomarkers, the dosage regimens were designed with an expected difference in therapeutic efficacy in favour of danofloxacin. Accordingly, the danofloxacin-treated pigs recovered clinically within 24h after treatment, whereas tiamulin-treated animals remained clinically ill until the end of the study, 48 h after treatment. A similar picture was seen for the biomarkers of infection. During the infection period, plasma C-reactive protein (CRP), interleukin-6 and haptoglobin increased, whereas plasma zinc, ascorbic acid and alpha-tocopherol decreased. In the danofloxacin-treated animals, CRP, interleukin-6, zinc, ascorbic acid and alpha-tocopherol reverted significantly towards normalisation within 24h of treatment. In contrast, signs of normalisation were absent (CRP, zinc and ascorbic acid) or less marked (interleukin-6 and alpha-tocopherol) in the tiamulin-treated animals. Plasma haptoglobin remained elevated throughout the study in both groups. This indicates that CRP, zinc, ascorbic acid and to a lesser extent interleukin-6 and alpha-tocopherol might be used to evaluate antibiotic treatment of acute Ap-infection in pigs. The present model provides a valuable tool in the evaluation of antibiotic treatments, offering the advantage of clinical and pathological examinations combined with the use of biochemical infection markers.

Copper-induced oxidation of epinephrine: protective effect of D-DAHK, a synthetic analogue of the high affinity copper binding site of human albumin

Epinephrine is known to be rapidly oxidized during sepsis. Ischemia and acidosis, which often accompany sepsis, are associated with the release of weakly bound cupric ions from plasma proteins. We investigated whether copper promotes oxidation of epinephrine at both physiological and acidic pH and whether D-Asp-D-Ala-D-His-D-Lys (D-DAHK), a human albumin (HSA) N-terminus synthetic peptide with a high affinity for cupric ions, attenuates this oxidation. Epinephrine alone [100 microM] or with CuCl(2) [10 microM], and with CuCl(2) [10 microM] and D-DAHK [20 microM] at pH 7.4, 7.0, 6.5, and 6.0 were incubated for 1h at 37 degrees C. Epinephrine oxidation was measured by the spectrophotometric quantification of its oxidation product, adrenochrome. We found that adrenochrome increased, suggesting copper-induced oxidation of epinephrine. At pH 7.4, 7.0, 6.5, and 6.0, adrenochrome increased by 47%, 53%, 24%, and 6% above baseline, respectively. D-DAHK attenuated the copper-induced oxidation of epinephrine to baseline levels. These in vitro results indicate that copper-induced epinephrine oxidation is greatest at the physiological pH 7.4 as well as in severe acidosis, pH 7.0, and that D-DAHK completely inhibits this oxidation.

Effects of long-term solvent exposure on blood cytokine levels and antioxidant enzyme activities in house painters

The aim of this study was to examine solvent-associated effects on blood cytokine levels, antioxidant enzyme activities, and malondialdehyde (MDA) concentration in house painters. Trace element (Cu and Zn) and nitrite and nitrate levels as well as protein concentrations in erythrocytes and serum were determined. Thirty male house painters and 30 male clerical workers were included in the study. There were 13 smokers and 17 nonsmokers in each group. Hemoglobin concentrations were significantly lower in house-painter blood compared to controls. House painters had significantly higher concentrations of erythrocyte protein (excluding hemoglobin), whereas no significant difference was observed between serum protein levels. Proinflammatory cytokine levels, such as tumor necrosis factor-alpha and interleukin-8, were significantly increased in house painters' sera. Interleukin-6 was below the detection limit of the assay in both groups. Interleukin-1beta and cytokine receptor interleukin 2R concentrations were not significantly affected. Furthermore, a three- to fourfold increase in nitrite and nitrate concentrations was found in house painters' sera. Serum superoxide dismutase (SOD) and glutathione peroxidase (GSHPx) activities were significantly lower in house painters compared to controls. Malondialdehyde (MDA) concentration, a measure of lipid peroxidation, was found to be significantly elevated. In house painters, erythrocyte carbonic anhydrase and catalase activities were elevated approximately 11- fold and 2-fold, respectively. Zinc levels were significantly decreased in house painters' sera. Smoking was not found to be a major confounder for the association between solvent exposure and blood parameters.

Copper inhibits activated protein C: protective effect of human albumin and an analogue of its high-affinity copper-binding site, d-DAHK

Activated protein C (APC) is useful in the treatment of sepsis. Ischemia and acidosis, which often accompany sepsis, cause the release of copper from loosely bound sites. We investigated (i) whether physiological concentrations of copper inhibit APC anticoagulant activity and (ii) if any copper-induced APC inhibition is reversible by human serum albumin (HSA) or a high-affinity copper-binding analogue of the human albumin N-terminus, d-Asp-d-Ala-d-His-d-Lys (d-DAHK). APC activity after 30 min of incubation with CuCl2 (10 microM) was decreased 26% below baseline. HSA, both alone and when combined with various ratios of CuCl2, increased APC activity significantly above baseline. d-DAHK alone and 2:1 and 4:1 ratios of d-DAHK:CuCl2 also increased APC activity. APC contained 1.4 microM copper, which helps explain the increased APC activity with HSA and d-DAHK alone. These in vitro results indicate that copper inhibits APC activity and that albumin and d-DAHK reverse the copper-induced APC deactivation.

Reference distributions for serum iron and transferrin saturation: a comparison of a large cohort to the world's literature

The appropriate clinical use of serum iron and transferrin saturation (TSAT) requires satisfactory reference intervals from birth to old age, and for males and females. This study identified 54 publications from 1974 to 2001 that met the criteria used in three prior meta-analyses, and these were analyzed statistically. A summary of our review is presented along with our reference population data on these measurements. This analysis places previous publications in perspective and suggests possible reasons for the observed differences. Previous studies of the individual analytes, serum iron, transferrin, and TSAT values agree with the reference ranges presented in this study, although the entire experience over time and between sexes has not been available before. Our 95% reference ranges are somewhat broader than those of the smaller studies, but they agree well with those of the larger ones.

Lower serum zinc in major depression in relation to changes in serum acute phase proteins

There is now some evidence that major depression is accompanied by activation of the inflammatory response system (IRS). Other signs of IRS activation, which have been reported in major depression are lowered serum zinc (Zn) and serum albumin (Alb) concentrations. In serum, Zn is closely bound to Alb. The aims of the present study were to replicate previous findings that major depression is accompanied by lowered serum Zn and Alb and to examine whether the decrease in serum Zn may be explained by that in serum Alb. The above variables were determined in 48 major depressed patients and in 15 age-sex-matched healthy volunteers. Serum Zn and Alb were significantly lower in major depressed patients than in normal volunteers. In healthy volunteers and major depressed patients, there were significant and positive correlations between serum Zn and Alb. We found that 53.8% of the variance in serum Zn could be explained by the combined effects of serum Alb and diagnostic classification. The results suggest that lower serum Zn in depression is in part explained by lowered serum Alb and by another depression-related mechanism. It is suggested that lower serum Zn in depression may be secondary to sequestration of metallothionein in the liver, which may be related to increased production of interleukin-6.

Early effects of surgery on zinc and metallothionein levels in female rats

Time-response effects of experimental surgery on zinc (Zn) and metallothionein (MT) homeostasis were investigated in female rats up to 24 h. Hepatic Zn content increased at 20 and 24 h postsurgery, whereas serum Zn levels decreased. Hepatic MT increased significantly by 9 h postsurgery and peaked at up to twofold of control at 12 h after surgery. Following the peak at 12 h, hepatic MT content decreased with time but did not reach control levels at the end of this study. When MT isoforms were evaluated, MT-II levels were elevated to the highest extent by 12 h after surgery, whereas MT-I levels started to decrease after 3 h postsurgery but then increased by 20 h. The early increases in MT content are probably mediated by nonmetallic mediators released during the postsurgical inflammatory process, favoring the plasma/tissue mobilization of Zn. This process might be part of the overall mechanisms occurring in the inflammation.

Inflammatory markers in younger vs elderly normal volunteers and in patients with Alzheimer's disease

BACKGROUND

Recently it has been reported that activation of the inflammatory response system (IRS) may play a role in the aging process and in the pathogenesis of the degenerative changes associated with Alzheimer's disease (SDAT). The aims of the present study were to examine the peripheral IRS in normal aging and in SDAT patients.

METHODS

Serum zinc (Zn), total serum protein (TSP), albumin (Alb), SP electrophoresis, and serum interleukin-6 (IL-6) and the stimulated production of tumor necrosis factor-alpha (TNFalpha) were determined in younger versus elderly healthy subjects and in SDAT patients vs. age-matched, healthy volunteers.

RESULTS

Serum Zn and Alb were significantly lower in elderly than in younger healthy volunteers and were significantly and inversely correlated with age. The production of TNFalpha was significantly higher in elderly than in younger healthy volunteers and was significantly and positively correlated with age. In SDAT patients, no significant changes in serum Zn or TNFalpha production could be found. Serum Alb was significantly lower and serum IL-6 and the alpha1 and alpha2 globulin fractions significantly higher in SDAT patients than in controls.

CONCLUSIONS

Activation of the IRS appears to accompany the normal aging process, i.e. lower serum Zn and Alb and increased TNFalpha production, as well as SDAT, i.e. lower serum Alb and increased serum IL-6 and alpha1 and alpha2 globulin fractions. The findings suggest that not all indicators of IRS activation in SDAT are related to those of the normal ageing process.

Blood levels of copper, iron, zinc, and lead in adults in India and Pakistan and the effect of oral zinc supplementation for six weeks

Deficiency in the intake of trace elements, such as copper (Cu), iron (Fe), selenium (Se), and zinc (Zn), is very common in the general population of most developing countries. A preliminary study in India and Pakistan showing the plasma levels of Zn and Fe indicates that approx 50% of the subjects who participated have low levels of both Fe and Zn, suggesting a marginal deficiency. The low plasma levels of these elements are more pronounced in females. The mean levels of Ze, Cu, and Fe in the plasma of 83 subjects were 0.71 +/- 0.11, 0.96 +/- 0.10, and 0.80 +/- 0.12 mg/L, respectively. The Cu:Zn ratio in the plasma was 1.43 +/- 0.16. Three groups of 15 subjects each were given three different levels of oral supplements of Zn (15, 30, and 45 mg of Zn as Zn gluconate) for 6 wk, and blood samples were analyzed during various intervals. Plasma concentration of Zn increased significantly (p < 0.001) in all the groups after 4 wk of supplementation and reached almost normal levels after 6 wk. Along with the increase in Zn, there was a significant decrease (p < 0.001) in plasma Cu levels. There were no changes in the concentration of Fe during the supplementation period. The supplementation was well tolerated by most subjects. The results of this pilot study indicate that Zn supplementation is a practical possibility comparable to that of Fe supplementation in order to prevent marginal Zn deficiency in vulnerable groups in the general population of developing countries.

Lower serum zinc in major depression is a sensitive marker of treatment resistance and of the immune/inflammatory response in that illness

The aims of the present study were to examine i) serum zinc (Zn) and copper (Cu) in treatment resistant depression (TRD); ii) the effects of subchronic antidepressant therapy on these trace elements; and iii) the relationships between serum Zn and Cu and immune/inflammatory markers. Serum Zn was significantly lower in TRD than in normal controls. There was a significant inverse correlation between baseline serum Zn and staging of depression based on severity of prior treatment resistance. There were no significant effects of antidepressive treatment on serum Zn, whereas serum Cu was significantly reduced. There were highly significant correlations between serum Zn and the CD4+/CD8+ T-cell ratio (negative), and total serum protein, serum albumin, and transferrin (all positive). The results suggest that lower serum Zn is a marker of TRD and of the immune/inflammatory response in depression. It is suggested that treatment resistance may bear a relationship with the immune/inflammatory alterations in major depression.

Trace elements in children with chronic and recurrent tonsillitis

Trace elements are indispensable for life and play a very important role in the essential functions. According to some reports in the literature lower trace element levels increase the susceptibility to recurrent infections. Since there are no reports available in the English literature about the effects of trace elements on recurrent and chronic tonsillitis, 37 children with recurrent and chronic tonsillitis were evaluated for Zn, Cu and Mg levels. Serum levels of Zn in 6 patients were slightly lower than the normal limit. All the other serum levels of Zn, Cu and Mg were within the normal range. On the other hand, the mean serum level of Zn in the 37 patients was significantly lower than in a control group of 28 age and sex matched children. In contrast, the mean serum levels of Cu and Mg in the patients were significantly higher than in the control group. Whether this alteration in the trace element status causes or fosters recurrent and chronic tonsillitis is not clear.

Interleukin-1 alpha (IL-1 alpha) production by alveolar macrophages in patients with acute lung diseases: the influence of zinc supplementation

The relationship between zinc treatment and interleukin-1 alpha (IL-1 alpha) production by cultured alveolar macrophages (AM) in patients with pulmonary tuberculosis and bacterial pneumonia was investigated. AM (1 x 10(6) cells/ml) from 6 patients with pulmonary tuberculosis, 7 patients with bacterial pneumonia and 4 healthy volunteers were cultured with either two different concentrations of zinc chloride (Znl = 1 microgram/ml and Zn2 = 5 micrograms/ml) or cell culture media alone (control) for an initial period of 6 hours and then stimulated with 3 different immunomodulator agents and reincubated for a further 24 h. IL-1 alpha in culture supernatants was measured by enzyme-linked immunosorbent assay (ELISA). In the absence of Znl or Zn2 Polyinosinic:Polycytidylic acid (Poly I:C 1 microgram/ml), Lipopolysaccharide (LPS 100 ng/ml) and Tumour necrosis factor-alpha (TNF-alpha 10 ng/ml) significantly increased the production of IL-1 alpha from AM in both patients and healthy subjects (p < 0.001) compared to control (media only). Zn1 and Zn2 significantly increased the production of IL-1 alpha (p < 0.001) in culture supernatants in the absence of either Poly I:C, LPS or TNF-alpha in patients but not in healthy group. In contrast, the presence of LPS or TNF-alpha significantly reduced Zn1 or Zn2-stimulated release of IL-1 alpha from AM in patients and healthy subjects (p < 0.01). However, Poly I:C decreased only Zn1-stimulated release of IL-1 alpha. These results suggest that zinc can regulate the production of IL-1 alpha from AM in patients with pulmonary tuberculosis or bacterial pneumonia.

Accumulation of metallothionein and its multiple forms by zinc, cadmium and dexamethasone in human peripheral T and B lymphocytes and monocytes

Metallothionein (MT) is produced at high rates in isolated monocytes, and T and B lymphocytes during induction in vitro. At optimal concentrations, 125 microM for Zn and 10 microM for Cd and dexamethasone (dex), MT was demonstrated after only 2 h in some cases, and in all cell types substantial levels were measured after 1 day of exposure to all three inductors. With Cd, lower amounts of MT were found, but maximum levels were reached faster than with Zn. The same result was found for dex compared to Zn. Zn and dex in combination showed the same accumulation rate as Zn alone. If the inductors were used in lower concentrations than optimal, reduced accumulation rates occurred, particularly during the first part of the exposure period. No MT was found for concentrations below 5 microM Zn, 1 microM Cd or 0.5 microM dex. The constitutive levels of MT (mean +/- S.E.M.) were 0.11 +/- 0.05, 0.54 +/- 0.3, 0.06 +/- 0.05 and 0.15 +/- 0.08 nmol Cd bound/5 x 10(6) unseparated mononuclear cells (MNC), monocytes, T lymphocytes and B lymphocytes, respectively. Monocytes accumulated 19 times and B lymphocytes 6 times more MT than T lymphocytes after 2 days of exposure to 125 microM Zn. Despite these differences in accumulated amounts of MT, the fold accumulation values were rather similar between the cell types, reflecting corresponding variations in background MT levels. After exposure of unseparated MNC to 125 microM Zn for 2 days, removal of the metal caused constitutive MT levels to be reestablished in 5 days. Five different MT forms, all capable of Cd complexation, were demonstrated in these cells. These forms had kinetically different behaviour during Zn exposure among the cell types, and the response to Cd was different from the Zn response. The results indicate metals to be closely controlled in MNC and emphasize a role for multiple MT forms in the process of regulation.

Hypozincemia in depression

This study investigates serum levels of zinc in 48 unipolar depressed subjects (16 minor, 14 simple major and 18 melancholic subjects) and 32 normal volunteers, and the relationships between zincemia and plasma neopterin levels, postdexamethasone adrenocorticotropic hormone and cortisol values, and anorexia-weight loss. Serum zinc levels were significantly lower in major depressed subjects than in normal controls, whereas minor depressed subjects showed intermediate values. There were significant negative correlations between serum zinc, and severity of depression and plasma neopterin concentrations. No significant relationships between zincemia and either postdexamethasone hormone values or anorexia/weight loss were found. The findings suggest that hypozincemia in major depression may be related to activation of cell-mediated immunity in that illness.

Antioxidant status and lipid peroxidation in patients infected with HIV

Deficiency in antioxidant micronutrients have been observed in patients with AIDS. These observations concerning only some isolated nutrients demonstrate a defect in zinc, selenium, and glutathione. An increase in free radical production and lipid peroxidation has been also found in these patients, and takes a great importance with recent papers presenting an immunodeficiency and more important an increase in HIV-1 replication secondary to free radicals overproduction. We have assessed different studies, trying to obtain a global view of the antioxidant status of these patients. In adults we observe a progressive decrease for zinc, selenium, and vitamin E with the severity of disease, except that selenium remains normal at stage II. However, the main dramatic decrease concerns carotenoids whose level at stage II is only half the normal value. To understand if these decreases in antioxidant and increases in oxidative stress occur secondary to the aggravation of the disease or, conversely, are responsible for it, we undertook a longitudinal survey of asymptotic patients. The preliminary results of this evaluation are presented. Paradoxically, lipid peroxidation is higher at stage II than at stage IV. This may be consecutive to a more intense overproduction of oxygen free radicals by more viable polymorphonuclear (PMN) at the asymptomatic stage. The free radicals production and lipid peroxidation seem secondary to a direct induction by the virus of PMN stimulation and cytokines secretion. N-Acetyl cysteine or ascorbate have been demonstrated in cell culture to be capable of blocking the expression of HIV-1 after oxidative stress and N-acetyl cysteine inhibits in vitro TNF-induced apoptosis of infected cells. In regard to all these experimental data, few serious and large trials of antioxidants have been conducted in HIV-infected patients, although some preliminary studies using zinc or selenium have been performed. In our opinion it is now time to evaluate in humans the beneficial effect of antioxidants. The more promising candidates for presenting synergistic effects when associated with N-acetyl cysteine seem to be beta-carotene, selenium and zinc.

Mitogenicity and metallothionein induction: two separate effects of zinc ions on human mononuclear blood cells

The mitogenic effect of elevated concentrations of zinc ions on human lymphocytes was found to be inhibited by the glucocorticoid hormone dexamethasone. The effect decreased progressively from complete block to partial inhibition when the culture period before the addition of dexamethasone was prolonged. In contrast, dexamethasone did not inhibit an induced formation of metallothionein in mononuclear cells. Furthermore, dexamethasone itself was found to induce small amounts of metallothionein. Apparently, the mitogenic effect and the induction of metallothionein by zinc ions in mononuclear cells occur by mutually independent mechanisms.

Increase in serum concentrations of IgG2 and IgG4 by selenium supplementation in children with Down's syndrome

In a previous study on children with Down's syndrome a reduced rate of infections was reported by their parents after the children had received six months' treatment with selenium supplements. In the present study the concentrations of the four IgG subclasses were measured in 29 of these children in samples of serum obtained before and immediately after the period of supplementation and one year after it had finished. Selenium had a significant augmentative effect on the serum concentrations of IgG2 and IgG4, but not of IgG1 and IgG3. This effect was not related to age, as among children over the age of 6 years the serum concentrations of IgG2 and IgG4 had decreased significantly one year after the treatment had been stopped. This study suggests that selenium has an immunoregulatory effect, which might be of importance in both basic research and clinical practice.

Induction of metallothionein production by zinc in human mononuclear cells

1. Low mol. wt proteins with high Cd-binding capacity were found to be induced by Zn in cultured monocytes and lymphocytes. 2. In T cell cultures one protein was found to be induced by 125 microM Zn for 6 days, while in monocytes and B enriched cells under these conditions two proteins were found, of which the one with higher mol. wt had similar electrophoretic mobility to the T cell protein on polyacrylamide gels. 3. Mol. wt criteria and crossreactivity towards anti-metallothionein (Mt) antibody identified these proteins to be Mts of about 23 and 27 kDa mol. wt. 4. Metal binding studies indicated that monocyte and lymphocyte Mts had a higher affinity to Zn compared to Cd than rat liver Mt and Mts from Cd-resistant substrains of a human epithelial and a murine fibroblast cell line. 5. The presence of the T cell mitogen phytohemagglutinin (PHA) was found not to be necessary for this Mt induction by Zn.

Superoxide production of peritoneal macrophages in experimental gram-negative sepsis; influence of in vitro and in vivo supplements of zinc

Although zinc is essential for the optimum function of the immune system, there is some controversy regarding treatment with zinc during acute infections where low serum zinc levels are often recorded. The aim of the present study was to investigate the influence of in vitro and in vivo zinc supplementation on the potentially toxic metabolic activity of peritoneal macrophages during infection. Rats were made septic by implanting a gelatin capsule containing known amounts of E. coli, and Bacteroides fragilis into the abdomen. Peritoneal macrophages were harvested by peritoneal lavage 72 hours after the induction of sepsis. Superoxide release was measured after stimulation with phorbol myristate acetate (PMA) or serum treated zymosan (STZ). Macrophages from septic rats released significantly higher amounts of superoxide compared with macrophages from sham operated controls after stimulation with both PMA and STZ. Following in vitro supplementation, zinc inhibited the superoxide production of macrophages harvested from septic rats after stimulation with both PMA and STZ. In vivo supplementation with zinc resulted in increased superoxide production from septic macrophages when stimulated with STZ, whereas stimulation with PMA produced no significant changes. Thus, in vitro incubation inhibited the superoxide production of peritoneal macrophages in intraabdominal sepsis, whilst in vivo administration of zinc produced no such effect, and the effect seemed to vary depending on the stimuli used to initiate the respiratory burst.