Magnesium in Infectious Diseases in Older People

Reduced magnesium (Mg) intake is a frequent cause of deficiency with age together with reduced absorption, renal wasting, and polypharmacotherapy. Chronic Mg deficiency may result in increased oxidative stress and low-grade inflammation, which may be linked to several age-related diseases, including higher predisposition to infectious diseases. Mg might play a role in the immune response being a cofactor for immunoglobulin synthesis and other processes strictly associated with the function of T and B cells. Mg is necessary for the biosynthesis, transport, and activation of vitamin D, another key factor in the pathogenesis of infectious diseases. The regulation of cytosolic free Mg in immune cells involves Mg transport systems, such as the melastatin-like transient receptor potential 7 channel, the solute carrier family, and the magnesium transporter 1 (MAGT1). The functional importance of Mg transport in immunity was unknown until the description of the primary immunodeficiency XMEN (X-linked immunodeficiency with Mg defect, Epstein–Barr virus infection, and neoplasia) due to a genetic deficiency of MAGT1 characterized by chronic Epstein–Barr virus infection. This and other research reporting associations of Mg deficit with viral and bacterial infections indicate a possible role of Mg deficit in the recent coronavirus disease 2019 (COVID-19) and its complications. In this review, we will discuss the importance of Mg for the immune system and for infectious diseases, including the recent pandemic of COVID-19.

Exercise, magnesium and immune function

Physical exercise may deplete magnesium, which together with a marginal dietary magnesium intake may impair energy metabolism, muscle function, oxygen uptake and electrolyte balance. Consequently, the ability to perform physical work may be compromised. Many aspects of immune function can be depressed temporarily by either a single bout of very severe exercise or a longer period of excessive training. Although the disturbance is usually quite transient, it can be sufficient to allow a clinical episode of infection, particularly upper respiratory tract infections. However, regular and moderate exercise has been reported to improve the ability of the immune system to protect the host from infection. Magnesium also has a strong relation with the immune system in both non specific and specific immune responses and magnesium deficit has been shown to be related to impaired cellular and humoral immune function. Magnesium deficiency leads to immunopathological changes that are related to the initiation of a sequential inflammatory response. Although in athletes magnesium deficiency has not been investigated regarding alterations in the immune system, the possibility exists that magnesium deficiency could contribute to the immunological changes observed after strenuous exercise.

[Study of anti-inflammatory activity of some organic and inorganic magnesium salts in rats fed with magnesium-deficient diet]

The purpose of the present research was comparative study of anti-inflammatory action of some Mg salts in rats fed with Mg-deficient diet. It was shown in our study that administration of Mg L-aspartate with pyridoxine leads to higher compensation of Mg deficiency in rats with diet-induced Mg depletion as compared with other Mg supplementations. According to the Mg deficiency correction rate Mg salts may be ranged in the following order: Mg L-aspartate with pyridoxine > or = Mg chloride with pyridoxine > or = Mg lactate with pyridoxine > or = Mg L-aspartate > Mg chloride > Mg orotate. In our study administration of Mg salts resulted in decreased number of blood leukocytes, reduced peripheral vasodilation visible in the external ear, decreased spleen weight, and as consequences in reduced inflammatory and immunological response. According to correction rate of the inflammatory response Mg salts may be ranged in the following order: Mg orotate > or = Mg chloride > or = Mg chloride with pyridoxine > or = Mg L-aspartate > or = MgL-aspartate with pyridoxine > or = Mg lactate with pyridoxine.

Morphological and immune response alterations in the intestinal mucosa of the mouse after short periods on a low-magnesium diet

The importance of Mg for the immune function is well recognized; however, there is no information available about the effect of Mg intake on the modulation of local immune response in the intestine. Thus, in the present study the hypothesis that short periods of Mg deprivation can affect intestinal mucosa and local immune response was tested. For this purpose, OF1 female mice were fed a semipurified diet (1000 mg Mg/kg diet). For 3 d before immunization and 1 d after, half of the animals were fed a Mg-deficient diet (30 mg Mg/kg diet), three immunizations per os were performed every 3 weeks with Escherichia coli producing the CS31A capsule-like protein (1010 or bacteria per animal). Mice were killed 10 d after the last immunization. The level of specific anti CS31A immunoglobulin (Ig) G and IgA in the serum and secretory IgA in the intestinal secretions and faeces were measured by ELISA. The results indicated that administration of a high dose of immunogen with a low-Mg diet led to lower specific IgA levels in the intestinal mucus and serum. Administration of a low dose of immunogen with a low-Mg diet led to lower IgA and IgG levels in the serum and secretory IgA coproantibodies. To assess alterations of intestinal mucosa caused by a low-Mg diet for a short period, histological and scanning electron microscopy analyses were performed on samples from mice (not submitted to the vaccination protocol) after 3 d on the Mg-deficient diet. These analyses showed several alterations, suggesting perturbations in the growth of the intestinal mucosa. These changes were accompanied by modifications in the expression of several genes involved in cell growth and stress response. From this present work, it may be concluded that short periods of Mg deprivation can affect the intestinal mucosa and local immune response of the intestine.

Protective effect of calcium deficiency on the inflammatory response in magnesium-deficient rats

BACKGROUND

Previous studies indicated that dietary Mg-deficiency in rats results in a marked pro-inflammatory effect. Since magnesium (Mg) frequently acts as a natural calcium (Ca) antagonist, the possibility exists that the pro-inflammatory effect of Mg-deficiency may be a consequence of a reduced extracellular Mg(2+)/Ca(2+) antagonism.

AIM OF THE STUDY

Thus, the aim of the study was to assess whether dietary Ca-deficiency improves the abnormal inflammatory response of Mg-deficient rats.

MATERIALS AND METHODS

Weaning male Wistar rats were randomly divided into 4 groups according to the dietary Mg and Ca as follows: Mg-adequate Ca-adequate (control), Mg-adequate Ca-deficient, Mg-deficient Ca-adequate, Mg-deficient Ca-deficient. Animals were fed the appropriate diets for 8 days.

RESULTS

Mg-deficient Ca-adequate rats as compared to controls displayed the usual decrease in plasma Mg, whereas the plasma Ca concentration was unaffected. The classical symptoms of inflammation including hyperemia, increased number of blood leukocytes and increased spleen weight were observed. In addition, these animals also showed an increase in heart lipid peroxidation and in plasma triglyceride concentration. In Mg-deficient rats, Ca-deficiency induced hypocalcemia and offered a significant protection against the pro-inflammatory effect of Mg-deficiency. This was evidenced by lower inflammation scores, prevention of leukocytosis and of spleen enlargement. The protective effects of Ca-deficiency on the inflammatory response in Mg-deficiency was accompanied by significant reduction in lipid peroxidation and by a normalization of plasma triglyceride concentration.

CONCLUSION

All together, the results suggest that Ca is implicated in the inflammatory response of experimental Mg-deficiency and that oxidative stress and hypertriglyceridemia are the results of the acute phase response following Mg-deficiency in rats.

Increased phagocytosis and production of reactive oxygen species by neutrophils during magnesium deficiency in rats and inhibition by high magnesium concentration

Recent studies underline the importance of the immunoinflammatory processes in the pathology of Mg deficiency. Neutrophils possess a superoxide anion-generating NADPH oxidase and its inappropriate activation may result in tissue damage. The aim of the present study was to assess the effect of experimental Mg deficiency in the rat on polymorphonuclear leucocytes (PMN) activity and the role of increasing extracellular Mg. Weaning male Wistar rats were fed either a Mg-deficient or a control diet for 8 d. In Mg-deficient rats, the characteristic inflammatory response was accompanied by a marked increase in the number of PMN. Higher plasma interleukin 6 and NO concentrations and increased lipid peroxidation in the heart were found in Mg-deficient rats as compared with control rats. As shown by chemiluminescence studies, basal neutrophil activity from Mg-deficient rats was significantly elevated when compared with neutrophils from control rats. Moreover, the chemiluminescence of PMN from Mg-deficient rats was significantly higher than that of control rats following phorbol myristate acetate or opsonized zymosan activation. PMN from Mg-deficient rats also showed an increased activity of phagocytosis in comparison with neutrophils from control animals. Increasing extracellular Mg concentration in the incubating medium of PMN (0.8 v. 8.0 mM) decreased the chemiluminescence activity of PMN from control rats following opsonized zymosan activation. Chemiluminescence activities of PMN from Mg-deficient rats following phorbol myristate acetate or opsonized zymosan challenge were also decreased by high extracellular Mg concentration. From this work, it appears that PMN activation is an early consequence of Mg deficiency and that high extracellular Mg concentration inhibits free radicals generation.

Inflammatory response following acute magnesium deficiency in the rat

The importance of inflammatory processes in the pathology of Mg deficiency has been recently reconsidered but the sequence of events leading to the inflammatory response remains unclear. Thus, the purpose of the present study was to characterize more precisely the acute phase response following Mg deficiency in the rat. Weaning male Wistar rats were pair-fed either a Mg-deficient or a control diet for either 4 or 8 days. The characteristic allergy-like crisis of Mg-deficient rats was accompanied by a blood leukocyte response and changes in leukocytes subpopulations. A significant increase in interleukin-6 (IL-6) plasma level was observed in Mg-deficient rats compared to rats fed a control diet. The inflammatory process was accompanied by an increase in plasma levels of acute phase proteins. The concentrations of alpha2-macroglobulin and alpha1-acid glycoprotein in the plasma of Mg-deficient rats were higher than in control rats. This was accompanied in the liver by an increase in the level of mRNA coding for these proteins. Moreover, Mg-deficient rats showed a significant increase in plasma fibrinogen and a significant decrease in albumin concentrations. Macrophages found in greater number in the peritoneal cavity of Mg-deficient rats were activated endogenously and appeared to be primed for superoxide production following phorbol myristate acetate stimulation. A high plasma level of IL-6 could be detected as early as day 4 for the Mg-deficient diet. Substance P does not appear to be the initiator of inflammation since IL-6 increase was observed without plasma elevation of this neuropeptide. The fact that the inflammatory response was an early consequence of Mg deficiency suggests that reduced extracellular Mg might be responsible for the activated state of immune cells.

Accelerated thymus involution in magnesium-deficient rats is related to enhanced apoptosis and sensitivity to oxidative stress

Experimental Mg deficiency leads to alterations in the immune response. Reduction of thymus weight and histological changes were previously observed in Mg-deficient rats after several weeks on a deficient diet, suggesting that functions of this immune organ may be affected by Mg deficiency. More recently, changes in the immune system during early Mg deficiency were shown. Thus, in the present study we examined modifications in the thymus during the early stages of Mg deficiency in weanling rats. From our results, it appears that Mg deficiency accelerates thymus involution. The assessment of apoptosis (enumeration of apoptotic cells on the basis of morphological criteria and intranucleosomal degradation of genomic DNA) showed greater values in thymuses from Mg-deficient rats as compared with controls. This was observed very early, since a significant difference was shown on the second day of deficiency, before reduced weight of thymus, which was recorded in the later period. These results indicate the relationship of accelerated thymus involution with an active process of cell death. Mg deficiency led to histological changes in the thymus. In the early stage of deficiency (second day) the presence of inflammatory cells was shown, suggesting that the inflammatory process was already occurring in the tissue studied. Later (eighth day) an increased proportion of epithelial reticular cells in the cortex was shown, indicating a remodelling process occurring in this period. Enhanced susceptibility to peroxidation also occurred very early during Mg deficiency. It may be hypothesized that disturbances in Mg status of short duration could have cellular effects with various deleterious consequences.

Exacerbated immune stress response during experimental magnesium deficiency results from abnormal cell calcium homeostasis

The aim of this study was to assess the potential mechanism underlying the enhanced inflammatory processes during magnesium deficit. In this study, exacerbated response to live bacteria and platelet activating factors was shown in rats fed a magnesium-deficient diet. Peritoneal cells from these animals also showed enhanced superoxide anion production and calcium mobilising potency following in vitro stimulation. The latter effect occurred very early in the course of magnesium deficiency. These studies first showed that an abnormal calcium handling induced by extracellular magnesium depression in vivo may be at the origin of exacerbated inflammatory response.

Early morphological and immunological alterations in the spleen during magnesium deficiency in the rat

Dietary magnesium deficiency in rodents, and especially in rats, causes inflammation and leads to alterations in the immune response. One of the characteristics of magnesium deficiency in the rat is a marked enlargement of the spleen. Considering the importance of the spleen for the immune response, in this study we have evaluated histological, cytological and immunological changes in this organ of rats in early stages of this deficiency. For this purpose, male weaning Wistar rats were pair-fed with either control or magnesium-deficient diet, for 2, 4 or 8 days. Results indicate that after 8 days on the deficient diet rats presented clinical signs of inflammation, splenomegalia and leukocytosis. As shown by histometrical analysis, both the red and white spleen pulps of deficient rats displayed an increased incidence of polymorphonuclear leukocytes and macrophages in all studied stages of deficiency. Concomitantly, the relative number of lymphocytes decreased. This observation was confirmed by the analysis of the cell suspension obtained from the spleen. The greater number of adherent cells in the cell suspension from deficient rats provides an additional confirmation of the increased number of macrophages in the spleen of these rats. Analysis of lymphocyte populations demonstrated a reduced proportion of CD5+ and CD8+ cells after 8 days of deficiency. The reduction in the number of CD8+ cells in deficient rats could be related to the observed decrease in IFN-gamma concentration in the spleen homogenate. In short, this study shows that magnesium deficiency causes early cytological and immunological modifications in the spleen which appeared before macroscopical changes in this organ and before clinical symptoms of inflammation. These changes could be related to the altered immune response of deficient animals.

Pathobiochemical effects of graded magnesium deficiency in rats

Severe Mg deficiency changed mineral homeostasis, induced membrane damage, increased lipid peroxidation and cytokine concentrations, and reduced immunocompetence. In order to investigate whether the pathobiochemical effects correlate directly with the degree of Mg deficiency or whether there might be a threshold with no detectable effects above, diets with 70, 110, 208, 330 and 850 ppm Mg were fed to growing Wistar rats. After feeding the diets for 0, 10, 20 and 30 days parameters of free radical action (malondialdehyde and vitamin E content), mineral content (Mg, Ca, Fe) in various tissues (liver, spleen, heart, kidney, muscle) and plasma parameters (Mg, Ca, Fe, alanine- and aspartate-aminotransferase) were measured. After 30 days 6-keto-prostaglandin F1 alpha, thromboxane B2, tumor necrosis factor-alpha, and immunoglobulins (IgG, IgM, IgA) were additionally analyzed. Tissue Mg content was either unchanged or only slightly reduced in severe Mg deficiency. Tissue Fe content rose when the extracellular Mg concentration was below 0.25 mM. There was a close positive correlation between tissue Fe and malondialdehyde content, and malondialdehyde was negatively correlated with vitamin E content. Below a threshold of about 0.25 mM plasma Mg concentration, transaminases increased in plasma. The same threshold could be observed for the increase of tissue Ca content, except in the kidney where calcifications were found already in mild Mg deficiency. Tumor necrosis factor-alpha and 6-keto-prostaglandin F1 alpha were increased when the plasma Mg concentration was below 0.15 mM, and thromboxane B2 was increased when plasma was lower than 0.25 mM. IgG and IgA were significantly reduced below 0.25 mM plasma Mg and IgM below 0.4 mM plasma Mg. Mild Mg deficiency, therefore, can be compensated and might not lead to pathological symptoms if not combined with other pathobiological conditions.

Marked alterations in circulating inflammatory cells during cardiomyopathy development in a magnesium-deficient rat model

Rodents fed on a Mg-deficient (Mg-D) diet develop cardiomyopathic lesions, as well as other types of cardiovascular dysfunction. In the rat, inflammatory cell infiltration of the myocardium begins to occur by week 1, and the lesions develop extensively in the third and fourth weeks on the Mg-D diet. Although the aetiologic mechanisms of Mg-D cardiomyopathy are unknown, we have previously reported that once plasma Mg is markedly reduced, one of the earliest molecular markers of the pathophysiological process is elevation of plasma substance P, calcitonin gene-related peptide and prostaglandin E2, followed by histamine and the inflammatory cytokines (interleukin-1, interleukin-6, and tumor necrosis factor-alpha). In order to evaluate the potential role of specific circulating inflammatory cell subpopulations in the mechanisms underlying pathophysiological changes observed in Mg-deficiency-induced cardiomyopathy, we analysed these cells by flow cytochemistry. Leucocyte subpopulation pools increased progressively in the Mg-D rats. Elevated circulating levels of neutrophils and lymphocytes appeared to contribute to both the acute (week 1-2) and chronic phases (week 3-4) of the inflammatory responses; monocytes, eosinophils, basophils and large unstained cells which are lymphoid in stained smears, on the other hand, increased significantly in the third and fourth weeks and thus contributed to the chronic inflammatory phase. Changes in the circulating leucocyte subpopulations paralleled the chronological progression of the cardiomyopathic lesions, particularly in weeks 3 and 4. Since a pronounced neutrophilia preceded leucocyte infiltration and deposition within the myocardial tissue, modifications of the microvascular barrier may be a prerequisite for cardiomyopathy in this model of neurogenic inflammation.

Immunoregulation by neuropeptides in magnesium deficiency: ex vivo effect of enhanced substance P production on circulating T lymphocytes from magnesium-deficient mice

The first week of dietary magnesium deficiency in rodent models is characterized by the induction of raised levels of neuropeptides (substance P [SP] and calcitonin gene related peptide [CGRP]), followed shortly thereafter by inflammatory cytokine release. Since neuropeptides participate in neurogenic inflammation, we have proposed that the neurogenic inflammatory response plays a role in the pathology of magnesium deficiency. However, the association between the early neuropeptide release and the subsequent pathology in this model remains unclear. Peripheral blood T lymphocytes were obtained from Balb/c mice fed a magnesium-deficient diet (approximately 1.8 mmol Mg/kg), or the same diet supplemented with 20 mmol MgO/kg. These cells were incubated in medium containing 10(-10) to 10(-5) M SP, after which the cells were examined for expression of SP receptors and the supernatants were collected and examined by immunochemical techniques for the presence of T lymphocyte associated cytokines. SP stimulation induced the secretion of interleukin (IL)-2, 4, 5, 10, 12, 13 and interferon-gamma (IFN-gamma). T lymphocytes from magnesium-deficient animals, when compared to magnesium-sufficient ones, secreted increased levels of these cytokines. The secretion of these cytokines was maximal at either 5 days (IL-4, IL-5) or 7 days (II-2, IL-10, and IFN-gamma) of magnesium deficiency. This increased sensitivity to SP appears to be related to an increased expression of SP receptors on the surface of T lymphocytes during the first week of magnesium deficiency. These data indicate that SP released early during magnesium deficiency exerts a regulatory role on T lymphocyte cytokine production, especially those cytokines regulating mast cell and immune responses leading to the onset of an immunopathological state.

Magnesium deficiency protects against Babesia hylomysci and mice become resistant to rechallenge with the parasite regardless of diet fed

Mice were fed diets containing 960 mg (control), 100 mg (moderately Mg deficient) and 30 mg (severely Mg deficient) of Mg/kg. After 20 days, mice were inoculated with Babesia hylomysci (from Dr. Wery, Anvers, Belgium). Significant increases in RBC Mg levels were observed following infection. All the control and moderately deficient mice died from infection, whereas the severely Mg-deficient diet protected mice against infection, as shown by a decrease in parasitaemia and mortality. The decrease in RBC Mg, modifications in membrane properties and increased oxidant stress are possible explanations for the protective effect of severe Mg deficiency. When mice were maintained for 2 months after inoculation on a severely Mg-deficient diet and were then switched to a control diet, all survived and had low parasitaemias. After 1 month, these mice were rechallenged with B. hylomysci and 89% survived.

A synergism of antigen challenge and severe magnesium deficiency on blood and urinary histamine levels in rats

The effects of severe and moderate magnesium (Mg) deficiency on blood and urinary histamine were studied in 36 male weanling Sprague-Dawley rats with or without IgE-stimulating antigen challenge. The rats were divided into six groups: two each on 50 (severely deficient), 300 (moderately deficient), and 2000 (control) ppm Mg diets without and with immunization with ovalbumin challenge on days 0, 14, and 29. Unimmunized severely Mg-deficient rats had significantly elevated urinary histamine which returned to normal by 22 days, but whole blood histamine was still significantly elevated at 36 days. Both blood and urinary histamine of immunized severely Mg-deficient rats were significantly higher than those of all the other groups throughout the study, particularly after the antigen challenge. There was a synergism of antigen challenge and severe Mg deficiency on blood and urinary histamine levels. The results suggest that severe Mg deficiency can aggravate diseases which are caused by abnormal histamine release after exposure to an IgE-stimulating antigen.

Effect of dietary magnesium on Ascaris suum infections of mice

Low amounts of dietary magnesium affected the inflammatory tissue response in nonimmunized mice differently than in immunized mice. Eosinophil numbers and LPL activity in lung tissue following infection with A. suum larvae were altered by the level of magnesium in the diets of mice. Average or higher dietary levels of magnesium resulted in decreased numbers of lung larvae indicating an overall protective effect. Increases in eosinophil numbers or LPL activity were not directly related to the numbers of larvae/lungs. Larvae/livers, eosinophil numbers, and LPL activity were affected by the types of magnesium diets that mice received. Nonimmunized mice had differences in larvae/liver (at 2 days and 7 days pi) and LPL activity (at 2 days pi). Immunized mice had varying findings at 2 days pi but a direct relationship between dietary magnesium and numbers of larvae, numbers of eosinophils, and liver LPL activity at 7 days pi.

Effect of magnesium deficiency on interleukin production by Fisher rats: effect of interleukins on reduced in vitro lymphocyte responses to concanavalin A and lipopolysaccharide

The ability of rats fed a magnesium-deficient diet to produce interleukins (ILs) and the effect of ILs on in vitro lymphocyte mitogenesis have been studied in rats. Lack of magnesium resulted in a lower number of plastic-adherent spleen cells and in a reduction of IL-1 production. IL-2 production was not significantly affected, indicating differential sensitivity of T cells to magnesium deficiency. The diminished mitogenic response of splenocytes to concanavalin A (Con-A) was restored by the addition of IL-1 supernatant, while the addition of IL-2 supernatant and recombinant IL-2 resulted in significantly greater enhancement of proliferation in response to Con-A, compared with that of control spleen cells. The fact that recombinant IL-2 restored the T-cell responses to Con-A indicates that the active factor in the IL-2 supernatant is IL-2.

Effect of varying levels of magnesium during gestation and lactation on humoral immune response and tissue minerals in rats

Weanling rats were maintained on diets which were Mg-adequate (49 mmol Mg/kg), groups 1 and 3, or Mg-deficient (8 mmol Mg/kg), groups 2 and 4, for 8 weeks of growth. During breeding, gestation, and lactation, groups 3 and 4 received diets supplemented with 41 mmol Mg/kg. Femur and cardiac Mg in group 2 dams was reduced, confirming that Mg deficiency was present. Thymic weight from dams and pups and numbers of plaque-forming cells in pups in group 1 were higher than in other groups while splenic weight in pups was lowest in group 2. Results indicate that maternal magnesium deficiency impaired immunocompetence in offspring. Regardless of the presence or absence of pregestational magnesium deficiency, magnesium supplementation also was associated with depressed immune function.

Magnesium-deficient hairless rat: spleen cells mitogenic responses and variations in hormonal status

Hairless rats with dermatosis induced with a poor magnesium diet were previously shown to bear biochemical and immunological abnormalities. It was therefore felt of interest to investigate the spleen cells proliferative responses from these rats, both in the rash and the remission phases, when testosterone and parathormone plasma levels were also determined. Results showed that proliferative responses to mitogens and PTH levels were inversely related to the intensity of the dermatosis, whereas testosterone levels were more or less decreased. The role of 1.25 dihydroxyvitamin D3 in these modifications is questionable.

Control of in vitro lymphocyte proliferation by copper, magnesium and zinc deficiency

Plant lectin-induced proliferation of lymphocytes in vitro in both whole-spleen cell and T cell-enriched cultures was markedly effected by depletion of media copper, magnesium or zinc. The T lymphocyte-oriented mitogens concanavalin A and phytohemagglutinin and the B lymphocyte-oriented mitogen lipopolysaccharide were used to study variations in [3H]thymidine incorporation in lymphocytes cultured in media deficient in one mineral element. Since the stimulatory action of these mitogens also relates to the interaction of lymphocytes with accessory cells, we looked at the phagocytic ability of accessory cells cultured in the depleted media. In addition, we determined the variations in cell surface markers for B lymphocytes (Ia), T lymphocytes (Thy 1.2, Lyt 1 and Lyt 2) and accessory cells (Ia). Media depleted of copper, magnesium or zinc did not support normal T-lymphocyte proliferation but did support normal B-lymphocyte proliferation. The phagocytic ability of magnesium-deficient and zinc-deficient accessory cells was also depressed. This was related to depressed Ia expressions in the magnesium-deficient and zinc-deficient whole-spleen cell cultures. Total T-lymphocyte numbers, as well as Lyt 1+ cell percentages, were unchanged by media depletion, whereas Lyt 2+ cell percentages were depressed in both copper-deficient and magnesium-deficient splenocyte cultures.

Dermatosis of hairless rats fed a hypomagnesic diet--pathology and immunology

The histopathology of hypomagnesic dermatosis in the hairless rat was studied on semithin sections, by electron microscopy, direct immunofluorescence and monoclonal antibodies to T cell subsets. We found primarily an edema of the epidermis and of the superficial dermis with a moderate mononuclear infiltrate and sometimes intraepidermal splits. The immunofluorescent study did not reveal any significant immune reactant within the skin. The comparison of our findings with the histopathology of the atopic dermatitis did not allow us to propose the hypomagnesic dermatosis as an animal model for human atopic dermatitis. We discuss some aspects of the pathogenesis of this chronic inflammatory dermatosis.

Nutrition and immune responses

Clinical and epidemiologic data suggest a causal relationship between nutritional deficiency and infection. Among other factors, impaired immune responses secondary to malnutrition increase susceptibility to infectious illness. Protein-energy undernutrition and deficiencies of iron, zinc, pyridoxine, and other nutrients depress a variety of immunity functions. Cell-mediated immunity, complement system, microbicidal activity of phagocytes, secretory antibody response, and antibody affinity are often decreased. Recent studies have revealed many metabolic and hormone alterations as well as changes in the number and function of lymphocyte subpopulations. Obesity also is associated with impaired cellular immune functions. Dietary factors may play a critical role in host resistance to disease.

Mineral deficiency effects on the generation of cytotoxic T-cells and T-helper cell factors in vitro

Generation of cytotoxic T-cell response of splenocytes was studied in vitro under copper, magnesium and zinc-deficient conditions. Viability of the short-term lymphocyte cultures in the deficient media was comparable with control condition viability. Cell mediated lympholysis (CML) was analyzed in an alloantigen-stimulated mixed lymphocyte culture (Balb/c versus CBA/H mice) using a 51Cr release assay. Lymphocytes cultured in copper and magnesium-deficient media failed to generate specific lysis to allogeneic target cells, whereas lymphocytes cultured in zinc-deficient media did generate T-killer cell activity at reduced levels. In examining the site of mineral deficiency effects, the actions of T-helper cell-produced factors was studied. There was no production of T-cell replacing factor (TRF) in any of the elementally deficient media by cultured splenocytes. The addition of TRF produced under normal control conditions to copper-deficient media completely restored the CML, whereas only a partial restoration of the CML was noted for the magnesium and zinc-deficient cells. The defect in the CML in the copper-deficient media appears to be focused on the T-helper cell, but magnesium and zinc deficiency effects appear to also be at other levels of cell differentiation and proliferation in the generation of CML.

[Blood histamine and response of spleen cells to phytohemagglutinins during moderate magnesium deficiency in the rat]

Blood histamine and spleen cell stimulation index by PHA were determined in either magnesium deficient or control Rats. Between the 10th and 17th days of diet (hyperemia and dermatosis period), histaminemia was significantly higher in deficient animals (485 ng/ml) than in control ones (112 ng/ml), but at the 32nd day it came back to normal values. The mean spleen cell stimulation index by PHA was depressed in deficient animals mainly between the 10th and 17th day of the deficiency; 33% of control mean value. A negative correlation is found between histamine level and stimulation index.

[Calcium and magnesium deficiency and C3 fraction of complement]

The third (C3) and fourth (C4) components of complement and C3 proactivator (C3PA) were determined in 55 children with low serum levels of calcium and magnesium and 30 normal children. The concentrations of serum C3, C4 and C3PA were significantly reduced in children with double deficiences of calcium and magnesium. There were significant correlations between calcium and C3 and magnesium and C3PA. The relations between calcium, magnesium and the classical or alternate pathway of complement systems are discussed.

Depressed immune response in the magnesium-deficient rat

The effects of dietary magnesium on growth, food efficiency, organ development, splenic nucleic acids, and serum antibody were studied in two experiments with male Wistar rats. Diets containing 30% protein from casein were fed ad libitum. Rats were immunized intravenously with sheep red blood cells. Blood was obtained 5 and 9 days after immunization. In experiment 1, a group of weanling rats was fed 10 ppm Mg for 8 days, followed by 142 ppm for 37 days. Group 2 (controls) was fed 480 ppm Mg for 45 days. Group 1 weighed less but had larger spleens, kidneys, and testes relative to body size than did group 2. Nucleic acids per gram spleen were similar in both groups as were serum gamma-globulin and its 19S and 7S components. Antibody log titers for group 1 were 45 and 65% of control agglutinin levels and 44 and 80% of control hemolysin values on days 5 and 9, respectively. In experiment 2,200-g rats were fed 10 (group 3) or 480 ppm (group 4) Mg for 38 days. Most effects of the 10 ppm Mg diet were similar to those seen in magnesium deficiency in experiment 1. Antibody titers for group 3 were 30 and 25% of control agglutinin and 43 and 53% of control hemolysin values on days 5 and 9, respectively. Total serum gamma-globulin and its 19S fraction were similar in both groups, while the 7S fraction of group 3 was only 64% of the control value.

The effect of magnesium deficiency in mice on serum immunoglobulin concentrations and antibody plaque-forming cells

Magnesium-deficient mice immunized with SRBC showed a significant decrease (P less than 0.001) in the number of PFC in their spleens compared with mice on a control diet. Serum immunoglobulin concentrations (IgG1, IgG2, IgA and IgM) were determined after 3, 6, 9 and 12 days on the respective diets. The serum IgG2 and IgM concentrations of magnesium- deficient mice were decreased (P less than 0.005) by 6 days and remained at these concentrations until 12 days. The serum IgG1 and IgA concentrations of magnesium deficient animals also decreased (P less than 0.01) by 6 days but returned toward control concentrations at 12 days. Serum magnesium concentrations confirmed the magnesium deficiency of the experimental animals. Therefore, magnesium deficiency has profound immunosuppressive capabilities in mice by significantly reducing the number of antibody synthesizing cells and serum immunoglobulin concentrations.