M.D. Ferrández

Immune function in aged women is improved by ingestion of vitamins C and E

We have investigated the effects of supplementation of the diet with the antioxidant vitamins C and E on several functions of the immune response of aged women. Ten healthy women and 20 women (72 +/- 6 years old) suffering two diseases often associated with age (10 with major depression disorders, MDD, and 10 with coronary heart disease, CHD) were administered 1 g of vitamin C and 200 mg of vitamin E daily for 16 weeks. Blood samples were collected before and after treatment for measurement of several immunological functions, namely proliferative response of lymphocytes to the mitogen phytohemagglutinin (20 mg/L) and phagocytic functions of polymorphonuclear (PMN) neutrophils, i.e., adherence to vascular endothelium, chemotaxis, phagocytosis of latex beads, and superoxide anion production. In addition, we also determined the levels of serum cortisol and lipid peroxides. Intake of vitamins resulted in a significant increase in the lymphoproliferative capacity and in the phagocytic functions of PMN neutrophils as well as in a significant decrease of serum levels of lipid peroxides and cortisol, both in the healthy aged women and in the aged women with MDD or CHD. These findings suggest an important role of antioxidant supplementation in the improvement of immune function in aged females as well as in the prevention and treatment of specific diseases associated with age that are quite prevalent in the developed countries.

Effects in vitro of several antioxidants on the natural killer function of aging mice.

The aim of the present work is to study the change with aging in the effect in vitro of several antioxidants: thiazolidine-4-carboxylic acid or thioproline, N-acetylcysteine (NAC), ascorbic acid (AA), and alpha-tocopherol (vitamin E, VE) on the natural killer (NK) activity in mononuclear cells from axillary nodes, spleen, thymus and peritoneal leukocytes from BALB/c male mice. Young (8+/-2 weeks), adult (24+/-2 weeks). mature (48+/-2 weeks), and old (72+/-2 weeks) animals were studied. A nonradioactive cytotoxic assay with cells from the murine lymphoma YAC-1 as target cells and a relation effector cells/target cells of 10/1 were used. The concentrations of the different antioxidants were: 1 mM for thioproline and N-acetylcysteine and 5 microM for ascorbic acid and alpha-tocopherol, which induced a maximum effect in our previous dose-response experiments. The results show that, in general, the above antioxidants cause an enhancement of the NK activity at all ages studied, this stimulation being higher with thioproline and N-acetylcysteine than with ascorbic acid and alpha-tocopherol. The effects were similar for the three lymphoid organs and the peritoneum. This stimulation of the NK activity by antioxidants is an important favorable response, especially in old mice, in which age results in a decrease in NK function and, therefore, in a higher incidence of neoplasia.

Effect of aging on the modulation of macrophage functions by neuropeptides.

The existence of a functional connection between the nervous and the immune system is supported by increasing recent evidence. In previous work we have shown that peptides from the nervous system, such as gastrin-releasing peptide (GRP), neuropeptide Y (NPY) and sulfated cholecystokinin octapeptide (CCK-8s), have modulatory effects on the immune functions in adult animals. Since the immunodepression found in aging organisms may be related to changes in the neuroimmune network, the aim of the present work was to study the changes with aging in the effect of CCK-8s, GRP and NPY on peritoneal macrophage functions (adherence to tissues, mobility, ingestion of foreign particles and superoxide anion production) from BALB/c mice of three different ages: adult (24+/-2 weeks old), mature (50+/-2 weeks old) and old (72+/-2 weeks old). The results show that the increase in adherence capacity produced by neuropeptides in cells from adult and mature animals disappears in old mice. The stimulatory effect of GRP and NPY on mobility, ingestion and superoxide production in macrophages from adult mice disappears (GRP) or changes to inhibition (NPY) in cells from old animals. The decrease of these functions caused by CCK-8s in adult or mature animals continues in old mice. These data suggest that the modulation by neuropeptides of the macrophage function changes with the age of animals.

Enhancement of leukocyte functions in aged mice supplemented with the antioxidant thioproline

Previous research has shown that supplementation of the diet with thioproline (thiazolidine-4-carboxylic acid), an intracellular sulfhydryl antioxidant and free radical scavenger, increases mouse life span and stimulates the immune system. In the present study aged Swiss mice (20 month old) fed thioproline (0.07%,w/w) for 5 weeks were used. Twelve month and 20 month old mice fed standard diet were used as controls. The lymphoproliferative response to the mitogen Concanavalin A (Con A) and the mobility of lymphocytes, both spontaneous and directed to a chemoattractant gradient (chemotaxis), as well as antibody-dependent cellular cytotoxicity (ADCC) and natural killer (NK) activity of leukocytes, were measured in cells from spleen and thymus. All of the above functions showed a significant decrease in aged (20 months) in comparison to adult mice (12 months). In aged animals, the ingestion of thioproline stimulated significantly the functions studied. Moreover, the age-related stress, revealed by the high corticosterone levels, was significantly decreased in animals fed this antioxidant. These data suggest that thioproline enhances immune response in the aged.

Changes with age in the modulation of natural killer activity of murine leukocytes by gastrin-releasing peptide, neuropeptide Y and sulfated cholecystokinin octapeptide

Several investigations have suggested that the interactions between the nervous and immune systems are modified with age. The aim of the present work was to study the effect of three neuropeptides: gastrin-releasing peptide (GRP), neuropeptide Y (NPY) and sulfated cholecystokinin octapeptide (CCK-8 s) on natural killer (NK) activity of spleen, thymus and axillary node leukocytes from BALB/c male, young (8+/-1 weeks), adult (24+/-2 weeks) and old (72+/-2 weeks) mice. We used cells from murine lymphoma YAC-1 as targets for the cytotoxic assay and three physiological concentrations of the neuropeptides (10(-8), 10(-10) and 10(-12) M). In control samples, in the absence of neuropeptide, we observed a decreased NK activity in young and old mice with respect to the adults in the three organs studied. Regarding the effect of the neuropeptides, GRP stimulates the cytotoxic activity of leukocytes from all locations, in adult animals. At the same age, NPY also stimulates the NK activity of leukocytes from axillary nodes and thymus, whereas it decreases the NK activity of spleen leukocytes from young mice. CCK-8 s has an inhibitory effect on the axillary node leukocytes from young mice and spleen leukocytes from old animals. However, CCK-8 s increased the NK activity of thymus leukocytes from young and adult mice. The results indicate that the highest values of NK activity are found in adult mice, and that the stimulating effect of the three neuropeptides studied on NK activity of leukocytes from adult mice are reduced or disappeared, in general, in old as well as in young animals. Furthermore, the changes observed with ageing in the modulation of NK activity by the neuropeptides studied suggest an altered integration of the nervous and immune systems.

Changes with aging and physical exercise in ascorbic acid content and proliferative response of murine lymphocytes

Ascorbic acid content and lymphoproliferative response to phytohemagglutinin were measured in lymphocytes from axillary nodes, spleen and thymus of young (15 +/- 2 weeks) and old (60 +/- 5 weeks) BALB/c mice. Ascorbic acid content in lymphocytes from spleen and thymus was found to be significantly higher and the lymphoproliferative response in the three immunocompetent organs significantly lower in old mice as compared to young mice. Moreover, young and old BALB/c mice were required to maintain a swimming activity until exhaustion (exhaustive exercise) or 90 min of swimming each day for a total of 20 days (continuous exercise). In both young and old mice the stress produced by exhaustive exercise and confirmed by the existence in serum of significantly increased levels of corticosterone compared to controls, caused a significant decrease in ascorbic acid content as well as in lymphoproliferative response. Continuous exercise, characterized by the presence in serum of significantly decreased levels of corticosterone compared to controls, produced the most significant decrease in ascorbic acid content from young and old murine lymphocytes. Moreover, this exercise resulted in a significant increase in lymphoproliferative response. Our results suggest that aging results in an increase in the ascorbic acid content of lymphocytes accompanied by a decline in the lymphoproliferative response in old BALB/c mice.

Changes with aging, sex and physical exercise in murine natural killer activity and antibody-dependent cellular cytotoxicity

Antibody-dependent cellular cytotoxicity (ADCC) and natural killer (NK) activity were measured in leukocytes from the axillary nodes, the spleen and the thymus of young (12 +/- 2 weeks) and aged (60 +/- 2 weeks) male and female BALB/c mice, which had performed an acute bout of exercise (moderate swimming until exhaustion) or a training exercise (90 min of moderate swimming each day for 20 days). The results show that NK and ADCC activity in sedentary mice (controls) were similar in young and aged animals. However, both kinds of exercise resulted in higher cytotoxicity values in aged mice than in young mice. Acute exercise did not have any effect on NK activity in young and aged mice, nor on ADCC activity in young mice as compared to controls, while training exercise stimulated both cytotoxicities in the two age groups. No correlations between serum corticosterone levels and NK or ADCC activity were found. Our results suggest that moderate training exercise improves both NK and ADCC activity during aging.

Anabolic steroids and lymphocyte function in sedentary and exercise-trained rats

The effects of the administration of suprapharmacological doses of anabolic steroids (AASs) on the immune system were examined in sedentary and exercise-trained rats by testing mobility and proliferative response in cultures of thymus and spleen-derived lymphocytes. Male Wistar rats were exercise-trained following two programmes of treadmill running of 3 months duration, differing in intensity, in the absence of treatment or with simultaneous i.m. administration of a suprapharmacological dose (10 mg/kg/week) of nandrolone decanoate (ND) or stanozolol (ST) during the past two months. At this dose ND reduced body weight gain, promoted a redistribution of immune cells from thymus to spleen, impaired lymphocyte mobility and inhibited the mitogen-induced proliferative response (about 90% inhibition for thymus-derived cells). Stanozolol (ST) treatment was without effect on body weight gain, but it also induced a redistribution of lymphocytes and modified the in vitro lymphocyte activity, although less severely than ND. Application of the high-intensity training programme reduced lymphocyte mobility and proliferation in vitro and a simultaneous treatment with anabolic steroids further impaired some of the immune cell responses. Application of the endurance-directed training programme, however, did not reduce mobility or mitogen-induced proliferation of lymphocytes, and normalized the activity of these cells in anabolic steroid-treated rats. So, endurance exercise, contrary to high-intensity training, could counteract the apparent negative effects of high doses of androgens on lymphocyte function.