Peter Frisk

Trace element balance is changed in infected organs during acute Chlamydophila pneumoniae infection in mice

Most infectious diseases are accompanied by changed levels of several trace elements in the blood. However, sequential changes in trace elements in tissues harbouring bacterial infections have not been studied. In the present study the respiratory pathogen Chlamydophilapneumoniae (C. pneumoniae), adapted to C57BL/6J mice, was used to study whether the balance of trace elements is changed in infected organs. Bacteria were quantitatively measured by real-time PCR in the blood, lungs, liver, aorta, and heart on days 2, 5, and 8 of the infection. Concentrations of 13 trace elements were measured in the liver, heart, and serum by inductively coupled plasma mass-spectrometry (ICP-MS). Infected mice developed expected clinical signs of disease and bacteria were found in lungs, liver, and heart on all days. The number of bacteria peaked on day 2 in the heart and on day 5 in the liver. The copper/zinc (Cu/Zn) ratio in serum increased as a response to the infection. Cu increased in the liver but did not change in the heart. Iron (Fe) in serum decreased progressively, whereas in the heart it tended to increase, and in the liver it progressively increased. C. pneumoniae may thus cause a changed trace element balance in target tissues of infection that may be pivotal for bacterial growth.

Gastrointestinal uptake of trace elements are changed during the course of a common human viral (Coxsackievirus B3) infection in mice.

Most infectious diseases are accompanied by a change in levels of several trace elements in the blood. However, it is not known whether changes in the gastrointestinal uptake of trace elements contribute to this event. Coxsackievirus B3 (CVB3), adapted to Balb/c mice, was used to study whether infection induces gene expression of metallothionein (MT1) and divalent-metal transporter 1 (DMT1) in the intestine and liver and hepcidin in the liver, as well as whether trace elements in these tissues are changed accordingly. Quantitative expression of CVB3, MT1, DMT1 and hepcidin was measured by real-time RT-PCR and six trace elements by ICP-MS on days 3, 6 and 9 of the infection. The copper/zinc (Cu/Zn) ratio in serum increased as a response to the infection. High concentrations of virus were found in the intestine and liver on day 3 and in the intestine on day 6. MT1 in the intestine and liver increased on days 3 and 6. The increase of MT1 in the liver correlated positively with Cu and Zn. Hepcidin in the liver showed a non-significant increase on days 3 and 6 of the infection, whereas DMT1 in the intestine decreased on day 9. Accordingly, iron (Fe) in the liver increased progressively during the disease, whereas in the intestine DMT1 was negatively correlated to Fe. Arsenic (As), cadmium (Cd) and mercury (Hg) were found to decrease to various degrees in the intestine, serum and liver. Thus, enteroviral infections, and possibly many other infections, may cause a change in the gastrointestinal uptake of both non-essential and essential trace elements.

Selenium protection against mercury-induced apoptosis and growth inhibition in cultured K-562 cells.

Selenium and mercuric chloride (MC) interactions regarding effects on cell growth and cell death have been studied. Human K-562 cells were pretreated or simultaneously treated with either selenite (5 or 50 µM) or selenomethionine (10 or 50 µM) and with MC (35 or 50 µM). The 35-µM MC treatments resulted in a clear inhibition of cell growth with no obvious difference between mercury-treated and mercury-selenium-treated cells. Furthermore, the apoptotic frequency was similar at all observations for all selenium treatments with 35 µM MC. In the simultaneously treated selenite and 50-µM MC combinations, a selenite-dependent protection was shown both by increased cell growth and by lower apoptotic frequency at 48 and 96 h of exposure. Both treatments with selenomethionine showed protection observed as an increased cell growth at 48 and 96 h and as decreased apoptotic frequency at 96 h of exposure.

Indications of selenium protection against cadmium toxicity in cultured K-562 cells

The interaction between selenium and cadmium was studied in relation to cellular uptake and expressions of selenium-cadmium interaction. Human K-562 cells were pre-treated or simultaneously treated with (5 or 50 microM) selenite or (10 or 50 microM) selenomethionine and with (60 or 75 microM) cadmium nitrate. Cells pre or simultaneously treated with selenite revealed increased cadmium concentration with increased doses of selenite, particularly pronounced in the simultaneous treatments. In both treatments, selenium protection was observed during the exposure period, but not during the growth period. In cells simultaneously treated with selenomethionine and 60-microM cadmium, an increase in cadmium concentration was observed after increased selenium dose. In addition, it was found that simultaneous selenomethionine treatment with 60-microM cadmium resulted in selenium protection during the exposure period, although protection was not observed during the growth period.

Selenite or selenomethionine interaction with methylmercury on uptake and toxicity showing a weak selenite protection: studies on cultured K-562 cells.

Selenium and methylmercuric chloride (MMC) interactions regarding cellular uptake and selenium protection on MMC toxicity have been studied. Human K-562 cells were pretreated or simultaneously treated with either selenite (5 or 50 µM) or selenomethionine (10 or 50 µM) together with (3.5 or 5 µM) MMC. Cells simultaneously treated with selenite or selenomethionine and 3.5 µM MMC showed a decreased mercury concentration with increased selenium dose especially seen in the selenite combinations. The simultaneous selenite and MMC 3.5 µM combinations showed growth curves with an increasing number of viable cells with increased selenite dose. All combinations with 5 µM MMC were toxic to the cells. Interactions between selenite or selenomethionine and MMC regarding cellular uptake of mercury and selenium were observed and indications of selenite protection against MMC toxicity in human K-562 cells were noticed.

Sequential effects of daily arsenic trioxide treatment on essential and nonessential trace elements in tissues in mice.

Despite arsenics (As) toxic potential, arsenic trioxide (As2O3) is used as a safe and effective treatment in acute promyelocytic leukaemia. However, it is unknown whether such therapy influences the balance of other trace elements in the body. In this study, mice were treated intraperitoneally daily with 1.0 mg As2O3/kg bw for 3, 5 or 7 days. As, and seven essential and nonessential trace elements with the potential to interact with As, were measured through inductively coupled plasma-mass spectrometry in serum, heart, lung, liver, pancreas, kidney, intestine and brain. As2O3 supplementation increased As in all target tissues on day 3, thereafter reaching an almost steady state. The major findings in other elements were a sequential decrease in serum zinc (on day 7 by 64%; P<0.001), and a decrease in selenium in the pancreas on day 3 (9%; P<0.05), in the intestine on day 3 (30%; P<0.001) and finally, in the brain on days 5 (12%; P<0.05) and 7 (15%; P<0.01). Changes in magnesium, iron, copper, cadmium and mercury were minor and inconsistent. This study suggests that supplementation with other trace elements may be beneficial when As2O3 treatment regimens are used in the clinic.

Influence of selenium on mercuric chloride cellular uptake and toxicity indicating protection: studies on cultured K-562 cells.

Selenium and mercuric chloride (MC) interactions regarding cellular uptake and selenium protection on MC toxicity have been studied. Human K-562 cells were pretreated or simultaneously treated with either selenite (5 or 50 µM) or selenomethionine (10 or 50 µM) together with MC (35 or 50 µM). Both treatments with selenite showed an increase of mercury uptake with increased selenium dose. In the pretreated or simultaneously treated selenite and 35 µM MC combinations, no inhibition of growth was seen, whereas all 50-µM MC combinations were toxic to the cells. A selenite-dependent protection was obtained for both exposure protocols when considering the cellular uptake of mercury. The cells died when the accumulation on d 4 reached more than about 0.8 × 10−15 mol/cell of mercury, whereas they survived up to twofold more mercury uptake when exposed to selenite. Selenomethionine gave, with a few exceptions, similar effects as selenite on MC uptake and toxicity.

NUCLEAR MICROSCOPY IN BIOMEDICAL ANALYSIS WITH SPECIAL EMPHASIS ON CLINICAL METAL BIOLOGY

Abstract Nuclear microscopy based upon developments in high energy ion beam techniques is by now an accepted technique in many fields of research. The advancements into the biomedical field have, however, been slower than expected. A major factor explaining this tendency is the availability of nuclear microscopy. This paper reviews briefly the biomedical work using nuclear microscopy that has been carried out since the 4 th International Conference on Nuclear Microprobe Technology and Applications held in Shanghai. Nuclear microscopy of isolated individual blood cells from patients adversely affected by metal exposure from dental amalgam has been performed both before and after removal of the metallic fillings. The elemental profile of blood cells was more or less normalised after treatment. Some of these results will be presented to illustrate a medical application. Results from bulk analysis by ICP-MS of erythrocytes and plasma before and after treatment will also be presented to illustrate the difference in information content between these two approaches as well as the need for complementary information in solving biomedical problems. As part of a larger study of acute porphyria, nuclear microscopy of blood cells was included among the 78 laboratory tests. The approach in this study was unbiased in the sense that no hypothesis was formulated as to which laboratory parameters would be the most explanatory for health or disease. Multivariate discriminant analysis was applied to the large amounts of data acquired. This approach led to the hypothesis that oxidative stress increased the synthesis of manganese-dependent superoxide dismutase in the mitochondria of polymorphonuclear leukocytes, explaining the increase of manganese in these cells. Antioxidant therapy was therefore applied to a couple of patients with porphyria, however, without clinical success.

Coxsackievirus B3 infection affects metal-binding/transporting proteins and trace elements in the pancreas in mice

Objective: The trigger of juvenile diabetes has been suggested to be an interaction between a virus and trace elements, where enteroviruses, including coxsackievirus B3 (CVB3), have been discussed as potential initiators. The aim of this study was to investigate the effects in the pancreas on gene expressions of metallothionein 1 (MT1), divalent metal transporter 1 (DMT1), and zinc transporter 5 (ZnT-5) and concomitant changes in iron (Fe), copper (Cu), and zinc (Zn) in serum and pancreas of Balb/c mice on days 3, 6, and 9 of CVB3 infection. Methods: Trace elements were measured through inductively coupled plasma-mass spectrometry, and CVB3, MT1, DMT1, and ZnT-5 were measured by reverse transcription-polymerase chain reaction. Results: Virus was found in the pancreas on all days, with a peak on day 3. Infection tended to increase Fe in both serum and the pancreas. The Cu/Zn ratio in the pancreas increased early in the infection because of a great decrease in Zn. In serum, the Cu/Zn ratio was not increased until day 9 of the disease. In the pancreas, MT1 decreased, whereas DMT1 tended to increase on day 6, and ZnT-5 increased progressively during the course of the disease. Conclusions: Virus-induced changes in trace elements, MT1, DMT1, and ZnT-5 in the pancreas may reflect early stages of the development of pancreatitis and prestages of diabetic disease.

Changed clinical chemistry pattern in blood after removal of dental amalgam and other metal alloys supported by antioxidant therapy

This study aimed to investigate a possible connection between removal of dental amalgam restorations supported by antioxidant therapy and indicative changes of clinical chemistry parameters. A group of 24 patients, referred for complaints related to amalgam restorations, underwent a removal of their amalgams. All patients were treated with antioxidants (vitamin B-complex, vitamin C, vitamin E, and sodium selenite). An age- and sex-matched control group of 22 individuals was also included. The mercury (Hg) and selenium (Se) concentration in plasma, Hg concentration in erythrocytes, and 17 clinical chemistry variables were examined in three groups: patients before amalgam removal (Before), patients after amalgam removal (After), and control individuals (Control). The Hg and Se values decreased (p < 0.05) in plasma, and the Hg concentration decreased (p < 0.05) in erythrocytes after amalgam removal. The variables serum lactate dehydrogenase (serum LDH) and serum sodium differed significantly both when comparing Control with Before (p < 0.01) and Before with After (p < 0.01). The variables white blood cell count (WBC), blood neutrophil count, blood eosinophil count, blood basophil count, blood lymphocyte count, blood monocyte count, serum potassium, and serum creatinine differed in the Before/After test (p < 0.05). Multivariate statistics (discriminant function analysis) could separate the groups Before and After with only one misclassification.