Protein restriction or calorie restriction? A critical assessment of the influence of selective calorie restriction on the progression of experimental renal disease.
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Animals↗
Biomedical subjects
G Fernandes
Publications and source records attributed to G Fernandes.
Effect of age and dietary restriction on the expression of alpha 2u-globulin.
The effect of aging on the expression of alpha 2u-globulin was studied in liver tissue from 6-30-month-old male Fischer F344 rats. The synthesis of alpha 2u-globulin by suspensions of isolated hepatocytes decreased 90% between 6 and 22 months of age. The levels of alpha 2u-globulin mRNA and the transcription of alpha 2u-globulin genes by isolated liver nuclei decreased 80-85% between 5 and 24 months of age. Because alpha 2u-globulin has been suggested to be a "senescence marker protein," the expression of alpha 2u-globulin was measured in rats fed a diet restricted in calories. This dietary restriction procedure has been shown to increase significantly the longevity of rodents. The expression of alpha 2u-globulin was compared in liver tissue from 18-month-old rats fed ad libitum and a restricted diet (40% restriction of total calories). The synthesis, mRNA levels, and transcription of alpha 2u-globulin were 1.8-3-fold higher for liver tissue from restricted rats compared to liver tissue from rats fed ad libitum. Therefore, dietary restriction alters the age-related change in the expression of alpha 2u-globulin. Our results demonstrate that the changes in alpha 2u-globulin expression that arise during aging or dietary restriction are regulated at the level of transcription.
Aging↗
Enhancement of natural killer-cell activity in young and old mice treated with cyclophosphamide on a circadian basis.
Several recent studies have revealed a significant circadian variation in immunological functions including natural killer (NK)-cell activity against tumor target cells both in rodents and in man. We have previously reported circadian changes in antibody-forming cells as well as NK-cell activity in mice and rats. The present study was undertaken to determine the effect of high and low doses of cyclophosphamide on circadian NK-cell activity in young (8-week-old) and old (8-month-old) female C57BL/6 (B/6) mice. The results revealed that, in general, young animals had higher NK activity than old animals. In both young and old mice, the high dose of cyclophosphamide depressed NK activity. In contrast, the low dose of cyclophosphamide showed significantly increased NK activity, which was proportionately greater in old mice than in young mice. Cyclophosphamide-enhanced NK activity was found to be higher during the resting period than during periods of activity. Apparently, high NK activity can be induced with a circadian-based immunotherapy regime using low-dose cyclophosphamide in both young and old animals. It is presently not clear if increased NK activity caused by cyclophosphamide is due to a decrease in activity of immunoregulatory cells, such as T cells, B cells, or macrophages. More studies are required to determine the basis of increased NK activity caused by treatment with low dosages of cyclophosphamide in mice.
Age Factors↗
Studies of immune responses in mice prone to autoimmune disorders. II. Decreased down-regulation by auto-anti-idiotype antibody in autoimmune-prone mice.
Three lines of evidence are presented which suggest that autoimmune-prone mice are deficient in the production of auto-anti-idiotype antibody during their immune response to trinitrophenylated Ficoll (TNP-F). NZB, MRL lpr/lpr and older BXSB male mice have no hapten-augmentable plaque-forming cells (PFC). Hapten-augmentable PFC have been previously shown to be cells whose secretion of antibody has been inhibited by the binding of auto-anti-idiotype antibody to cell surface idiotype. Sera from TNP-F immunized NZB mice lack PFC inhibiting activity (anti-idiotype antibody). Spleen cells from TNP-F immune NZB mice fail to transfer anti-idiotype antibody-mediated suppression to naive mice as do spleen cells from immune non-autoimmune-prone mice. Taken together these data suggest that autoimmune-prone mice are deficient in auto-anti-idiotype antibody-mediated downward regulation of their immune responses. It was further shown that the immune response of NZB mice to TNP-F shows a slower decline in splenic PFC and a greater heterogeneity of PFC affinity than do the responses of non-autoimmune-prone strains. Since athymic (nude) mice, which were previously shown to be defective in the production of auto-anti-idiotype antibody, also show a slower decline in splenic PFC and an increased heterogeneity of PFC affinity, it is suggested that these peculiarities of the immune responses of autoimmune-prone and athymic mice are also the consequences of the lack of auto-anti-idiotype antibody-mediated down-regulation.
Animals↗
Augmentation of natural killer cytotoxicity by alpha or gamma natural and recombinant interferons and interferon inducers. Effect of monocytes.
We investigated the effect of human peripheral blood monocytes on the augmentation of natural killer cytotoxicity by alpha or gamma natural and recombinant interferons (IFN) and certain interferon inducers. We observed that: (1) in the majority of the donors examined (75%) human peripheral blood monocytes do not affect natural killer cytotoxicity, determined by a 4-hour chromium-51 release assay, against target cells from hemopoietic human tumor cell lines. (2) Monocytes are not required and do not affect the augmentation of natural killer cytotoxicity by Escherichia coli-derived IFN-gamma, natural human IFN-gamma, E. Coli-derived IFN-alpha 2 or natural human IFN-alpha. E. Coli-derived IFN-gamma and natural human IFN-gamma have been reported to activate monocyte cytotoxicity determined in 72-hour assay. (3) Monocytes are not required for the augmentation of natural killer cytotoxicity against target cells from hemopoietic tumor cell lines by polyinosinic acid-polycytidylic acid or staphylococcal enterotoxin A.
Cells, Cultured↗
Reduction of blood pressure and restoration of T-cell immune function in spontaneously hypertensive rats by food restriction and/or by treadmill exercise.
The studies were carried out to compare the effects of food restriction and/or treadmill exercise on the development of high blood pressure and to compare immune function in spontaneously hypertensive rats (SHR). The results demonstrate that moderate food restriction from weaning or a regular treadmill exercise not only maintains significantly lower blood pressure, but also increases T-cell proliferative response against mitogens which is found to be significantly depressed in SHR fed ad libitum. A significant loss of T-cell subpopulation such as W3/25+ T helper cells and OX8+ non-helper T-cells occurring in mice fed ad libitum were restored to normal levels, including IL-2 response, in food-restricted SHR. Our results suggest that both food restriction and/or physical exercise is effective in modulating the blood pressure and increasing T-cell immune functions in SHR.
Animals↗
DNA and RNA analysis by flow cytometry of the leukemia in AKR mice.
The development of the leukemia-lymphoma complex was studied in AKR/J (H-2k) mice using flow cytometry and staining with acridine orange. Investigation of cytokinetics and of cellular RNA content showed that during the neonatal period all mice had a significant increase of S phase cells in the thymus, bone marrow, lymph nodes and spleen reflecting extramedullary hematopoiesis. Concomitantly, G0/G1 cells were significantly reduced in the thymus, lymph nodes and spleen when compared to 6-week old mice of the same strain. No changes in the cell cycle or in RNA content were observed until 10 months of age in congeneic AKR (H-2b) mice, which do not develop leukemia during the first year of life. In leukemia-prone AKR/J (H-2k) mice, however, it was shown that the first appearance of a leukemic process may be recognized in the thymus by a significant increase of cells in G1 phase of the cell cycle which have a high RNA content. These changes were first seen at 5 months of age before the increased expression of MuLV antigen signals preleukemic alterations at 6 months of age and long before morphological changes appear (8-10 months). Furthermore, at 6 months these mice showed a significant elevation of cells in S phase which always appeared initially in the thymus. By 10 months of age, when the mice were overtly leukemic, these changes had progressed in all lymphoid organs and in the peripheral blood. At the same time a unique population of cells was observed that was characterized by cells in S and G2M with very low RNA content. The method used is applicable to further analysis of the precise locus of development of leukemia in the thymus of AKR/J (H-2k) mice, analysis of the nature of the earliest malignant cells, and investigation of the influence of viruses in the pathogenesis of AKR leukemia.
Animals↗
Alterations in immunological reactivity in encephalomyocarditis virus-induced murine diabetes. I. Defective primary IgM plaque forming cell responses to sheep erythrocytes: correction by islet cell transplantation.
Increasing data suggest a possible viral aetiology of juvenile onset, insulin-dependent diabetes mellitus. The M variant of the encephalomyocarditis (EMC) virus infects murine pancreatic beta cells and causes a diabetes like syndrome in susceptible strains of mice. Abnormalities in immunological function have been documented in patients with diabetes mellitus and in spontaneous, streptozotocin-induced and alloxan-induced diabetes in animals. The present study documents a significant impairment of the ability of mice with EMC virus (M variant)-induced diabetes to generate a direct, IgM PFC response after in vivo immunization with sheep erythrocytes. This abnormality appears to be a direct consequence of the diabetic state and not EMC virus infection, per se, since mice infected with EMC virus that do not become diabetic have normal direct PFC responses and islet cell transplantation, which cures the diabetes, corrects the defect in PFC responsiveness.
Animals↗
Suppression of cellular and humoral immunity to T-dependent antigens by calorie restriction.
Calorie restriction is known to preserve the immunologic function and prolong the life span of autoimmune-susceptible mice. In order to determine the influence of calorie restriction on cellular and humoral immunity, we tested lymphocyte proliferative response and antibody response to T-dependent antigens in C57Bl/6 mice maintained on restricted diets. C57Bl/6 mice fed a low-calorie diet demonstrated a marked reduction in T-dependent-antigen-specific lymphocyte proliferation and antibody response when compared to mice fed ad libitum. The depressed lymphocyte response seen in calorie-restricted animals is attributed to a defect in both the macrophages and T cells in antigen processing, presentation, and/or proliferation.
Animals↗
Age-dependent alterations of peritoneal exudate macrophages in autoimmune-prone and autoimmune-resistant mouse strains.
Comparisons were made with age on phagocytosis, chemotaxis, and esterase staining of autoimmune-resistant and autoimmune-susceptible mouse strains. Consistent increases of each parameter occurred with age. Autoimmune strains generally showed less change with age than autoimmune-resistant mice and the changes with aging were less consistent. These findings suggest that phagocytic cells may play an important role in the autoimmunities or the lymphoproliferative processes that occur in autoimmune-prone mice and/or in loss of immune function with aging.
Age Factors↗
Alterations in immunological function in streptozotocin-induced murine diabetes mellitus: correction by islet cell transplantation.
Cell-mediated and humoral immune responses of streptozotocin-induced diabetic mice were evaluated using in vivo and in vitro immunological assays. C57BL/6 mice were rendered diabetic by a single intraperitoneal injection of 125-200 mg/kg of streptozotocin. Immunological studies were performed after the mice were diabetic (mean +/- SEM serum glucose 537 +/- 14 mg/dl) for a minimum of 4 weeks. Spleen cells from streptozotocin-induced diabetic mice exhibited significantly diminished direct IgM plaque-forming cell (PFC) responses following either in vivo or in vitro immunization with sheep erythrocytes, markedly impaired cytotoxic cell responses following in vivo or in vitro allogeneic stimulation, and diminished blastogenic response to the T-cell mitogens phytohemagglutinin and concanavalin A. In contrast the blastogenic response of diabetic spleen cells to lipopolysaccharide, a B-cell mitogen, was normal. The defects in in vivo PFC responses and in vivo cytotoxic cell responses were corrected by islet cell transplantation, suggesting that the abnormalities in immunological function of streptozotocin-induced diabetic mice are a consequence of the diabetic state and not of direct streptozotocin toxicity to lymphoid cells.
Animals↗
Inhibition by restricted-calorie diet of lymphoproliferative disease and renal damage in MRL/lpr mice.
Restriction of calorie intake from the time of weaning greatly prolongs life, and it inhibits development and expression of the lymphoproliferative syndrome, renal disease, and decline of certain immunologic functions with age in MRL/lpr mice. This dramatic influence of diet on mice of this short-lived autoimmunity-prone strain, while associated with decreased rate of growth, is not associated with debilitation or apparent disease in the MRL/lpr mice. The massive lymphadenopathy and splenomegaly that developed in the putatively well-fed animals was prevented by dietary restriction, as were histopathologic abnormalities of thymus, spleen, lymph nodes, and kidneys.
Animals↗
Functional T cells in athymic nude mice.
After passage of spleen cells from nu/nu mice over a nylon wool column, concanavalin A-responsive cells can be detected in the presence of 2-mercaptoethanol, and specific cytotoxic T lymphocytes can be generated without exposure to interleukin 2 (IL-2). The spleen cells of the nu/nu mice born of nu/nu parents and nursed by nu/nu mothers had significantly fewer Thy-1+ T cells and a lesser capacity to generate cytotoxic T lymphocytes than did the conventionally bred nu/nu mice. Nonetheless, such cells were clearly present. IL-2 may act to cause these post-thymic T cells to proliferate. Therefore, it seems inappropriate to consider IL-2 as an inducer of the differentiation of T cells in the absence of thymic influence on the basis of the capacity of IL-2 to induce the appearance of a T-lymphocyte population in nu/nu mice.
Animals↗
Effects of nutrition on disease and life span. I. Immune responses, cardiovascular pathology, and life span in MRL mice.
Mice of the autoimmune, lymphoproliferative strain MRL/lpr and the congenic, nonlymphoproliferative strain MRL/n were fed one of six diets from weaning on-ward. These mice were sacrificed at 3 or 5 months of age. Low fat diets resulted in lower cholesterol and higher triglyceride levels than did cholesterol-containing high-fat diets. Caloric restriction of MRL/lpr mice was associated with an increased plaque-forming cell response to trinitrophenylated polyacrylamide beads, less lymphoproliferation, and less severe glomerulonephritis. Diet did not affect the incidence of autoimmune vasculitis in MRL/lpr mice sacrificed at 5 months. MRL/lpr mice fed a low-fat, calorically restricted diet from 5 months of age to death lived longer than mice which were fed ad libitum a cholesterol-containing, high-fat diet. At death, MRL/lpr mice fed the former diet had the autoimmune vasculitis which had been evident in mice killed at 5 months, whereas mice fed the latter diet, in addition to the vasculitis, had a high incidence of atherosclerotic lesions of intrarenal and aortic branch arteries.
Animal Nutritional Physiological Phenomena↗
In vitro immune response of cells of various lymphoid tissues in (NZB X NZW)F1 mice: evidence for abnormality of the mesenteric lymph node cells.
Autoimmune-prone (NZB X NZW)F1 (B/W) mice have been shown to have a variety of immunologic perturbations. However, most studies have been performed with spleen cells. By using the Mishell-Dutton culture system, we examined the in vitro immune response of the various lymphoid tissue to determine whether an imbalance at a selective lymphoid site may exist in B/W mice. It was shown that the ability of mesenteric lymph node (MLN) cells of B/W mice to generate plaque-forming cells (PFC) in response to sheep red blood cells was consistently less than that of the spleen cells. This relationship held true in the aged mice. In contrast, the ability of the MLN cells of other strains not prone to develop autoimmunity to generate PFC was higher than that of the spleen cells. No significant difference in the mitogenic response of the lymphoid cells from various lymphoid tissue in the young B/W mice was seen, as compared with normal lymphoid cells from control mice. However, it was demonstrated that a relative decrease of B cells and immunoregulatory Lyt-123+ cells in the MLN in the B/W mice occurred early in life, and it was concluded that this abnormality may account for the low PFC response observed.
Aging↗
Nutritional factors: modulating effects on immune function and aging.
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Aging↗
Deficient T-cell mitogen response in murine experimental autoimmune myasthenia gravis: a defect in the adherent cell population.
T-Lymphocyte number and functions are often reduced, while B-lymphocyte function is often increased in patients with autoimmune disorders. To study the mechanisms responsible for these T-cell malfunctions in autoimmunity we adapted the murine experimental autoimmune myasthenia gravis (EAMG) model. Splenocytes from C57BL/6 mice immunized with acetylcholine receptors (AChR) in complete Freund's adjuvant (CFA) produced approximately half the amount of concanavalin A (Con A)-induced interleukin 2 (IL-2) as did splenocytes of CFA-inoculated controls. Further, AChR plus CFA-immunized splenocytes showed a marked reduction in T-cell proliferative responses induced by Con A or phytohemagglutinin when compared with CFA-inoculated controls. By contrast, lipopolysaccharide-induced B-cell function is preserved. Deficient Con A splenic T-cell response is seen early after secondary inoculation with CFA or AChR in CFA. T-Cell recovery occurs in CFA-inoculated mice but not in AChR plus CFA-inoculated mice. Defective Con A splenic T-cell response seen early after secondary immunization with CFA or AChR in CFA is due to the presence of a defective splenic adherent cell population. Moreover, defective Con A splenic T-cell response seen after established autoimmunity to AChR in EAMG is also due to the presence of a defective splenic adherent cell population.
Animals↗
Age-related changes in lymphoid tissue content of prostaglandins in (NZB X NZW)F1 and CBA/H mice.
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Aging↗