Circadian temporal organization of lipidic fractions in elderly people. Entrainment to the dietary schedule.
OBJECTIVE
Changes in some rhythmometric parameters have been reported in the elderly as a consequence of both structural and neurochemical changes occurring in the central nervous system. Since alterations of lipid and lipoprotein metabolism are directly involved in several age-related disorders, the aim of this study was to investigate the circadian temporal organization of some important lipidic fractions (total cholesterol, triacylglycerol, apolipoprotein A1 and B) in physiological aging.


METHODS
Thirty old hospitalized subjects were synchronized for daily activities, sleeping/waking habits, and time/quality of meals. Twenty-four healthy young individuals served as controls. After an overnight fast, samples were taken beginning at 08:00 every 4 hours until 20:00, and every 2 hours from 20:00 to 04:00. Rhythmometric data were analyzed by single and population mean Cosinor analysis, and by ANOVA; the comparison of the rhythm's parameters between elderly and young subjects was carried out by the Mesor test and the amplitude-acrophase using Hotelling's test.


RESULTS
Elderly subjects exhibited statistically significant circadian rhythms for total cholesterol (p<0.00002), triacylglycerol (p<0.000001), apo A-1 (p<0.0013), and apo B (p<O.0104). Young subjects also exhibited statistically significant daily fluctuations for total cholesterol (p<0. 0003), triacylglycerol (p<0. 03), apo A-1 (p<0.002) and apo B (p<0.003). The mean level of apo B rhythm was higher in old subjects than in controls.


CONCLUSIONS
These data suggest that the circadian temporal organization of lipidic fractions is maintained in physiological aging and underline the importance of the feeding schedule as a powerful synchronizer of the daily lipidic profile.
Trotti
Rosita
R
Laboratory of Biochemical Chemistry, Neurological Institute C. Mondino I.R.C.C.S., University of Pavia, Italy. rtrotti@mail3.telnetwork.it
Rondanelli
Mariangela
M
Cuzzoni
Giovanni
G
Ferrari
Ettore
E
d'Eril
Gianvico Melzi
GM
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D016632:Apolipoprotein A-I / Q000097:blood; D001055:Apolipoproteins B / Q000097:blood; D002784:Cholesterol / Q000097:blood; D002940:Circadian Rhythm / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood*; D008297:Male; D014280:Triglycerides / Q000097:blood
D016632:Apolipoprotein A-I; D001055:Apolipoproteins B; D008055:Lipids; D014280:Triglycerides; D002784:Cholesterol