Neuroendocrine-immune interactions in healthy aging.
OBJECTIVE
The nervous, endocrine and immune systems are connected by shared neurotransmitters, hormones and cytokines. The function of these systems shows patterns of circadian rhythmicity and a number of age-related changes in the 24-h hormonal and non-hormonal rhythms have been found in older human beings. The aim of this study was to evaluate integration among the nervous, endocrine and immune systems in the elderly.


METHODS
Cortisol and melatonin serum levels were measured and lymphocyte subpopulation analyses were performed on blood samples collected every 4 h for 24 h from 15 healthy young-middle-aged subjects (range 36-55 years, mean age±standard error [SE] 44.08±1.76) and 15 healthy old-aged subjects (range 67-79 years, mean age±SE 68.52±1.27).


RESULTS
There was a statistically significant difference between the groups in the observed values of CD20 (total B cells higher in young-middle-aged subjects, P=0.02), CD25 (activated T cells with expression of the α-chain of interleukin-2 receptor, higher in elderly subjects, P=0.04) and DR+ T cells (activated T cells higher in elderly subjects, P=0.01). There were different correlations among lymphocyte subpopulations and hormone serum levels in young and middle-aged subjects in compared to old-aged subjects. In the group of young-middle-aged subjects, a clear circadian rhythm was validated for the time-qualified changes of all the factors studied. In the group of elderly subjects, a clear circadian rhythm was validated for the nyctohemeral changes of CD3 (with a phase delay of 3 h), CD8, CD4/CD8 ratio, CD16, CD25 (in opposite phase), cortisol (with a phase delay of 1 h) and melatonin.


CONCLUSIONS
The results of the current study show that aging is associated with enhanced responsiveness of the T-cell compartment, impairment of B-cell compartment and alterations in temporal architecture and correlations of neuroendocrine-immune parameters.
Mazzoccoli
Gianluigi
G
Department of Internal Medicine and Chronobiology Unit, Scientific Institute and Regional General Hospital Casa Sollievo della Sofferenza, S. Giovanni Rotondo, Italy. g.mazzoccoli@tin.it
Inglese
Michele
M
De Cata
Angelo
A
Carughi
Stefano
S
Dagostino
Mariangela Pia
MP
Marzulli
Nunzia
N
Damato
Marcello
M
Grilli
Massimo
M
Giuliani
Francesco
F
Greco
Antonio
A
D000311:Adrenal Glands / Q000378:metabolism; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D018951:Antigens, CD20 / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D005500:Follow-Up Studies; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007111:Immunity, Cellular / Q000502:physiology*; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology; D008297:Male; D008550:Melatonin / Q000097:blood*; D008875:Middle Aged; D009490:Neurosecretory Systems / Q000502:physiology*; D010870:Pineal Gland / Q000378:metabolism; D012016:Reference Values; D013601:T-Lymphocytes / Q000276:immunology*
D018951:Antigens, CD20; D053645:Interleukin-2 Receptor alpha Subunit; D008550:Melatonin; D006854:Hydrocortisone