L. Pénzes

Density of substance P, vasoactive intestinal polypeptide and somatostatin-containing nerve fibers in the ageing small intestine of the rats.

Immunoelectron microscopic investigations were carried out to study the substance P, vasoactive intestinal polypeptide (VIP) and somatostatin immunoreactive nerve elements in the wall of the small intestine. In young and old animals a large number of immunoreactive nerve fibers were found in all layers of the small intestine. They were observed closely to the epithelial cells, to the blood vessel basement membrane and to the smooth muscle cells and in some cases they were observed in a synapse with other unlabelled nerve fibers. On the other hand, in the senile animals very few immunoreactive nerve fibers were observed, calculated for a 100 micron2 tissue area. In the senile animals the overall number of nerve fibers was decreased in comparison to the young and old animals and most of them were in degeneration. This change could be the cause of the changes in the senescence-related epithelial transport processes and furthermore, of the modifications of the overall intestinal motility of the gastrointestinal tract, resulting in the age-dependent transit rates.

Promotional effects of plant volatile oils on the polyunsaturated fatty acid status during aging

Protection of polyunsaturated fatty acids within the liver of old mice was realized by the ingestion of culinary and medicinal plant volatile oils containing natural antioxidants obtained by hydrodistillation. This protection effectively reversed the normal trend in polyunsaturated fatty acid metabolism during aging wherein a decrease in levels is concomitant with a reduction in tissue function and integrity. Volatile oil from thyme was overall the most effective in this protective capacity.

Effect of Essential Oils on the Lipids of the Retina in the Ageing Rat: A Possible Therapeutic Use

Abstract A study has been made on the effects of the dietary administration of a selection of volatile oils from medicinal plants on the polyunsaturated fatty acid composition in the retina of aged (28 month old) rats. Polyunsaturated fatty acids comprised by far the major proportion of the total unsaturated content within the retinal phospholipids with docosahexaenoic acid predominating. The administration daily of 3-9 mg of the essential oils from clove, nutmeg, pepper and thyme over a period of 17 months resulted in the maintenance of very much higher levels of polyunsaturated fatty acids, in particular docosahexaenoic acid, within the retinal phospholipids. This increase occurred mainly at the expense of a reduction in the level of oleic acid. The possible efficacy for the application of the oils from such medicinal plants through their antioxidant capacities in the prevention of age-related macular degeneration is discussed.

Intestinal absorption of some heterocyclic and aromatic amino acids from the ageing gut

Abstract Intestinal absorption of l -tryptophan, l -phenylalanine and l -proline was studied in vivo for 20 min, on 6-month, 12-month and 27-month-old rats. Initial concentrations were of 1, 2, 5 and 10 mM (try), 5, 10, 20 and 30 mM (phe) or 10, 20, 40 and 80 mM (pro), respectively. Absorption rates were calculated using the Lineweaver-Burk relationship to establish the Michaelis constants (Km and Vmax) for each amino acid. It is concluded that there is no real difference bbetween the tryptophan absorption of the young and old rat. In the case of the phenylalanine and proline experiment, age-dependent changes of intestinal absorption were revealed. These findings were partly confirmed by analyzing the 14C incorporation ratios of the liver to intestine of the phenylalanine studies.

Effect of 2-mercaptoethanol on some metabolic indices of ageing of CBA/Ca inbred mice

It has been shown in several studies that 2-mercaptoethanol (2-ME) improves the life span and aspects of life performance of laboratory animals. To obtain further details on the beneficial effects of 2-ME, a long-term study has been performed on male CBA/Ca inbred mice treated with this antioxidant. Four month-old mice were each given 4 micrograms of 2-ME in physiological saline via intraperitoneal (i.p.) injection 3 x per week. Measurements were made of the following: cold tolerance (heat performance), apparent total body protein turnover (T1/2), changes in the major lipid and fatty acid compositions of the liver, superoxide dismutase activity and formation of malondialdehyde and observations on a range of pathological changes. It was found that the basal rectal temperatures of the treated mice were higher and in the oldest group, heat performance capacity was better than those of the controls. After about 1 year of age the apparent biological half-life time of total body protein (T1/2) was observed to be shorter in the treated mice. Significant increases were observed to occur in the proportions of the polyunsaturated fatty acids in the lipids of the liver in the mice injected with 2-ME. Although no differences were observed in the superoxide dismutase activities, malondialdehyde concentrations in the livers of the experimental mice were significantly increased. Autopsy data showed that Dunn-sarcomas associated with amyloidoses occurred more frequently in the untreated mice.

Effect of an antioxidant compound (2-mercaptoethanol) on the nerve terminals of the aging small intestine

The effect of 2-mercaptoethanol (2-ME) treatment on the nerve elements of the small intestine has been investigated in old mice. In control animals only a few synapses and a very small number of vesicles were found in the nerve terminals. Some of the nerve fibers were observed to be degenerating. After drinking 2-ME daily for 17 months, both the number of synapses and vesicles within the nerve terminals increased. No degenerated fibers were observed. It is assumed that 2-ME has a beneficial influence on the peripheral intestinal nervous system increasing the number of synapses and the vesicle population in the nerve terminals.

Effect of aging on cold tolerance and thyroid activity in CBA/Ca inbred mice.

Relationships between cold tolerance, serum levels of thyroxine (T4), thyronine (T3), and thyrotropine (TSH), and thyroid morphometry have been investigated in male CBA/Ca inbred mice at various ages through their life span. From the data obtained it appeared that there was an age-related decrease in cold tolerance up to 18 months of age which was followed by an increase, the age effect being most apparent in relation to cold resistance and cold tolerance during the recovery period following cold exposure. The age-related changes in cold tolerance appeared to be associated with changes in the serum concentrations of T3, T4, and TSH. In contrast to the T3 serum levels which showed a decrease at 36 months, the thyroxine contents showed a perceptible decrease from the age of 12-18 months onwards. A similar pattern was observed for the TSH levels, with a peak at 21 months, followed by a decline at 30 months. A relationship with age between serum T4 level and thyroid weight was indicated together with structural changes in the thyroid gland, particularly during senescence, for example the size and number of thyroid epithelial cells had become enlarged by 30 months of age.

Thyroid hormones in the light of general health status of Hungarian centenarians

Serum levels of thyroxine (T4), 3,5,3′tri-iodothyronine (T3), and thyrotropin (TSH) of Hungarian centenarians were analyzed using RIA methodology and compared to hormone levels from young and adult (control) individuals. Age was indirectly correlated to serum T3 values. Serum T4 levels did not change with age. The T3 values of less healthy female centenarians were found to be lower than those of age-matched “healthy” persons. Serum TSH concentrations were noted to increase with age.

Long-term observations on the effect of polyadenylic acid in mice of different ages

In order to better life performance, polyadenylic acid (poly (A) ) was given intraperitoneally to CBA/Ca mice for almost a two-year period. This substance, as one of the components of double-stranded polynucleotides (like poly A:U), is known to improve some immune responses of the aging organism. Five approaches (changes in body-weight, adaptation to cold stress, biological half-life of body proteins, mortality and pathology) were applied to test the effects of this substance on life performance. It was found that the beneficial effects of double-stranded polynucleotides cannot be mimicked by polyadenylic acid only, despite its anti-senescence effect, namely, it accelerates the apparent protein turnover, cf., biological half-life. Polyadenylic acid shortens life-expectancy (because of the higher mortality rate of mice). Possible mechanisms of these actions are discussed.