Biomedical subjects

B Muzzoni

Publications and source records attributed to B Muzzoni.

3 recordsLinked to original sources

PubMed2002

Thyroid function in physiological aging and in centenarians: possible relationships with some nutritional markers.

Changes in thyroid function are often described in elderly subjects; however, their pathophysiologic significance and the possible contributory role of both malnutrition and nonthyroidal illness are still debated. The aim of this cross-sectional study was to investigate thyroid function in relationship to some markers of the nutritional status in a group of healthy old subjects and in some centenarians living in nursing homes. Patients included 24 clinically healthy elderly women (age, 71 to 93 years), 24 clinically healthy centenarian women (age, 100 to 106 years), and 20 healthy young subjects (age, 22 to 33 years). Blood samples were drawn from each subject for the evaluation of thyroid-stimulating hormone (TSH), free triiodothyronine (FT(3)), free thyroxine (FT(4),) reverseT(3) (rT3), autoantibodies against thyroglobulin (AbTg) and against thyroid peroxidase (AbTPO), and for the main humoral nutritional markers. TSH and thyroid hormones were assayed by fluoroimmunometric method; rT3 and thyroid autoantibodies by radioimmunoassay (RIA) and enzyme chemiluminescent immunometric assay, respectively. The mean values of TSH, FT(3) and FT(4) fell within the normal range in both groups. However, by comparison to old controls, in centenarian subjects, TSH levels were significantly lower, whereas rT(3) concentrations were slightly, but significantly, increased. Autoantibodies positivity was found in 4.16% of centenarians and in 10.4% and 13.6% of old and young controls. Thus, the incidence of thyroid autoantibodies was lower in centenarians than in old controls. Except for transferrin, lower than the normal range in centenarians, all of the other nutritional markers evaluated fell within the laboratory range of normality. Total cholesterol levels were significantly reduced in centenarians by comparison to old controls. Our results showed an age-related decline of the TSH levels and a significant increase of the rT(3) concentrations in centenarians by comparison to old controls. These findings may be related to an age-dependent reduction of the 5'-deiodinase activity rather than to important changes of nutritional markers.

Adult↗

PubMed2001

Age-related changes of the adrenal secretory pattern: possible role in pathological brain aging.

The biosynthetic dissociation of the adrenocortical secretion occurring with age may have a pathogenetic role in the pathophysiology of brain aging. We studied cortisol and DHEAS secretion in healthy old and young subjects, in senile dementia, in major depression of elderly subjects and in healthy centenarians. A clear age-related decline of DHEAS secretion was well evident in healthy centenarians, and a further decrease in DHEAS concentration was found in old depressed patients and moreover in the demented ones, by comparison with age-matched controls. The circadian profile of serum cortisol was clearly flattened in old subjects, due to the selective increase in the cortisol nocturnal levels, particularly evident in demented subjects; on the other hand, the morning serum cortisol levels were not significantly different among centenarians, young and old controls. The molar ratio between cortisol and DHEAS showed a significant age-related increase; the occurrence of senile dementia and of major depression played an additive role, by comparison to physiological aging. The qualitative and quantitative modifications of the adrenocortical secretion occurring with aging seem mainly dependent on age itself, but the occurrence of pathological conditions may amplify these changes. Since cortisol and DHEAS play opposite effects on the central nervous system, the evaluation of the ratio between cortisol and DHEAS seems to be a good marker of the neuroendocrine features in old subjects.

Adrenal Glands↗

PubMed2001

Age-related changes of the hypothalamic-pituitary-adrenal axis: pathophysiological correlates.

The aim of this review was to examine the evidence for age-related changes of the hypothalamic-pituitary-adrenal (HPA) axis in both physiological and pathological aging, on the basis of the many data in the literature, as well as of our personal findings. A statistically significant circadian rhythmicity of serum cortisol was maintained in elderly subjects, even if with a reduced amplitude of the 24 h fluctuations and a trend to an increase of the serum levels in the evening and at night-time, in comparison with young controls. Furthermore, an age-related impairment of HPA sensitivity to steroid feedback was present in elderly people. The occurrence of senile dementia amplified the changes already present in physiological aging. While the cortisol secretion was generally well maintained in aging, the adrenal production of dehydroepiandrosterone and of its sulfate (DHEAS) exhibited an age-related decline. Therefore, the cortisol/DHEAS molar ratio was significantly higher in elderly subjects and even more in demented ones, than in young controls. Due to the opposite effects of cortisol and DHEAS on the brain and particularly on the hippocampal region, the imbalance between glucocorticoids and androgens occurring in physiological and even more in pathological aging, may have adverse effects on the function of this region, whose key role in learning and memory is well known.

Aging↗