Survey of thymic hormone effects on physical and immunological parameters in C57BL/6NNia mice of different ages

Assessment of the ovine acute phase response and hepatic gene expression in response to Escherichia coli endotoxin

Lipopolysaccharide (LPS), a bacterial membrane endotoxin, induces a systemic inflammatory response (IFR) through the activation of blood monocytes and hepatic kupffer cells. These cells secrete pro-inflammatory cytokines, which subsequently activate the hypothalamic-pituitary-adrenal axis (HPAA) to release cortisol, an anti-inflammatory hormone that regulates the IFR and subsequent immune response (IR). The intent of this study was to characterize the acute phase response in female sheep challenged systemically with a range of doses of Escherichia coli endotoxin. Yearling ewes were challenged with an i.v. bolus dose of LPS (0, 200, 400, 600 ng/kg BW) and the acute phase response assessed by measuring serum interleukin (IL)-6 and cortisol concentrations, and the febrile response over time. A follow-up liver biopsy study was performed to determine kinetic differences in the expression of eight candidate hepatic genes between LPS dose groups using real-time RT-PCR. The initial time trail did not follow a linear dose response relationship with respect to the febrile and HPAA response to LPS challenge. Serum IL-6 concentrations increased in the two highest treatment groups but did not correlate with the observed febrile and HPAA response. The expression of Toll-like receptor 4, CD14, IL-6, tumor necrosis factor-alpha, IL-1beta, macrophage migration inhibitory factor, 11-beta-hydroxysteroid dehydrogenase (HSD), and tachykinin precursor 1 hepatic genes was dependent on both the dose and the kinetics of the response to LPS.

Life span extension and cancer risk: myths and reality

A significant increase in the number of old people in the populations of developed countries was followed by an increase in morbidity and mortality resulting from main age-related diseases -- cardiovascular, cancer, neurodegenerative, diabetes mellitus, decrease in resistance to infections. Obviously, the development of the means of prevention of the premature aging of humans is crucial for the realization of this program. However, data available on such kind of means are rather scarce, contradictory and are often not reliable from the points of view of the adequacy of the experiments to current scientific requirements as well as the interpretation of the results and safety. Data available on the increase in life span and the adverse effects of the following geroprotectors were critically analyzed: antioxidants, chelate agents and lathyrogens, succinate, adaptogens and herbs, neurotropic drugs, inhibitors of monoamine oxidase, glucocorticoids, dehydroepiandrosterone, sex and growth hormones, melatonin, pineal peptide preparations, protein inhibitors, antidiabetic biguanides, thymic hormones and peptides, immunomodulators, enteroadsorbents, lypofuscin inhibitors, as well as calorie intake restriction and special diets. Most of the available results were insufficient and could not provide convincing evidence for the life span extension and the safety of the suggested geroprotectors. Drugs and means prolonging the life span could be subdivided into three groups: (a) geroprotectors prolonging the life span equally in all the members of the population: these postponed the beginning of the population's aging; (b) geroprotectors decreasing the mortality rate in a long-lived subpopulation, which raised their maximal life span: these slowed down the population's aging rate; (c) geroprotectors increasing the survival rate in a short-lived subpopulation without changes in the maximal life span: in this case, the aging rate increased. There was a high positive correlation between the type of geroprotector-induced aging delay and the pattern of tumour development in the same population of animals. The first type of geroprotectors did not influence the incidence of tumour but increased tumour latency. The second type of geroprotectors was effective both in the inhibition of spontaneous carcinogenesis and the increase in tumour latency. Certain drugs of the third type raised tumour incidence in the exposed populations. According to the multistage model, geroprotectors either inhibit or accelerate the passage of carcinogen-exposed cells form one stage to another. Thus, the efficacy of geroprotectors as preventive means of cancer development will decrease with respect to the age of exposure onset. Recommendations of the available drugs and means of life span increase should be carefully reconsidered under the international scientific control.

Effect of synthetic thymic and pineal peptides on biomarkers of ageing, survival and spontaneous tumour incidence in female CBA mice

Fifty female CBA mice were injected s.c. either with 0.1 ml saline, or with synthetic thymic dipeptide Lys-Glu or with synthetic pineal tetrapeptide Ala-Glu-Asp-Gly both in a single dose of 0.1 microg/animal monthly for five consecutive days from the age of 6 months until natural death. Lys-Glu did not significantly influence the body weight and food consumption, free radical processes and estrus function in mice and did increase their physical activity with the subsequent decrease in spontaneous lung adenomas incidence. The pineal peptide treatment was failed to modify the food consumption and physical strength of mice, and was followed by the increase in the body weight, mean survival (by 5.3%, P<0.05) and maximum (by 10 months), by slow down of the ageing of estrus function, by the decrease in body temperature, physical activity, free radical processes and spontaneous tumor incidence (mainly, lung adenomas) in mice. These data suggest the geroprotector potential of the pineal peptide.

Effect of vilon on biological age and lifespan in mice

Subcutaneous administration of vilon (Lys-Glu) to female CBA mice starting from the 6th month of life increased physical activity and endurance, decreased body temperature, prolonged the lifespan, and prevented the development of spontaneous neoplasms. Vilon had no effect on age-related changes of estrous function and free radical processes. Long-term administration of vilon caused no unfavourable effects on animal development. The obtained results show safety of chronic vilon administration and allow to use this preparation for geroprotection and prophylaxis of age pathology.

Reversing and restoring immune functions

Restoration of immunological functions is keenly needed for the improvement of quality of life of the elderly as the elderly population is rapidly increasing throughout the world. A brief review was made on the methods to restore or reverse immunological functions in the aged human and animals, including those presented in the Mini-Symposium at the 1st International Conference on Immunology and Aging. The methods discussed were (1) grafting of cells and tissues, (2) dietary manipulation, (3) free radical scavengers or anti-oxidants, (4) thymic peptides, (5) endocrine manipulation and (6) physical exercise. There is no easy and simple method for immunological restoration, as people are variable in terms of genetics, habit and culture. We need comprehensive study to test the effect of combination of a few or several methods for immunological restoration.

Infections and diabetes: mechanisms and prospects for prevention

Infections remain a serious hazard for the diabetic patient. Good metabolic control is a major factor in limiting the development and spread of infections and, most importantly, the development of diabetic complications which predispose to infections. In some patients recurrent infections can pose a problem, particularly if there is evidence of secondary immunodeficiency. In these patients adjuvant therapies, including Biological Responses Modifiers (BRMS) should be considered. Several factors could predispose diabetic patients to infections. These factors include: genetic susceptibility to infection; altered cellular and humoral immune defense mechanisms; local factors including poor blood supply and nerve damage, and alterations in metabolism associated with diabetes. In the context of a diabetic patient all or some of these factors may operate. The purpose of this review is to assess the relative contribution of these potential mechanisms in leading to infection in patients with diabetes.

Effect of thymic hormone treatment on several immune functions of nude mice

Studies of the effect of short-term, intense treatment with thymic hormone on mitogen response, cytotoxicity to EL-4 lymphoma and natural killer cell (NK) activity was investigated Balb/c nude mice (about 12-16-week-old) were treated 5 times per week for 3 weeks with: Facteur Thymic Serique (FTS) and Thymopentin (TP5, Thymopoietin 32-36) at 1 microgram and 10 ng; TM4 1 ng (an enzyme resistant variant of FTS); Thymosin Fraction V (TF5), 10 and 1 microgram; and 0.1 ml saline, and killed 2 days after the last treatment. The animals were monitored for changes in weight, hematocrit, peripheral blood lymphocyte (PBL) and spleen mitogen response. Additional groups of nude mice were immunized with 1 x 10(7) 5000 R irradiated EL-4 cells 10 days before sacrifice and tested for the presence of cytotoxic T-lymphocytes (CTL). The results show that weight and hematocrit were similar among the groups. Treatment with FTS significantly elevated the number of PBL. Spleen stimulation in mice treated with 1 microgram TP5 was depressed to mitogen concanavalin A (ConA) and lipopolysaccharide (LPS) stimulation. The phytohemagglutinin (PHA) response was not different among the treatment groups. The PBL mitogen response to ConA and LPS was generally increased over saline control in the hormone treated groups but was not statistically significant. The PHA response was only slightly elevated. No CTL was generated in nude mice in any of the groups. However, there was a statistically significant general depression of NK activity in all of the hormone treated animals compared with saline. The results indicate that the basic differentiation defect of the T-cells of nude mice cannot be restored to full functional activity by short-term treatment.