Aging and dietary modulation of elastase and interleukin-1 beta secretion.
Aging is associated with diminished immune function that may stem from alterations in arachidonic acid metabolism and lipid peroxidation. This study sought to determine if dietary modification of fatty acids influenced neutrophil and monocyte secretion after an in vivo inflammatory stress in older human subjects. Volunteers participated in protocols that forced their quadriceps muscles to lengthen during tension development (eccentric stress). These protocols can cause inflammatory foci in the muscle as well as alterations in circulating leukocyte function. In this study, in vivo neutrophil degranulation was assessed by plasma elastase concentrations, and mononuclear cell function was assessed by interleukin-1 beta (IL-1 beta) secretion in vitro. In response to eccentric stress, older subjects (> 60 yr old) taking a placebo had no apparent elastase response, whereas those taking fish oil supplements responded with a 142% increase in plasma elastase (P = 0.011), similar to responses of younger reference subjects (< 33 yr old) taking no supplement. Overall, elastase responses correlated with individual plasma arachidonic acid-to-eicosapentaenoic acid ratios (r = -0.881, P = 0.004). Thus apparent age-related differences in elastase release were reconciled by individual differences in fatty acid nutriture. No significant temporal changes in urinary lipid peroxide excretion or IL-1 beta secretion were observed; however, age-associated differences were found.
United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts.
J G
JG
Cannon
M A
MA
Fiatarone
M
M
Meydani
J
J
Gong
L
L
Scott
J B
JB
Blumberg
W J
WJ
Evans
D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D004311:Double-Blind Method; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005260:Female; D005395:Fish Oils / Q000494:pharmacology*; D005498:Follicular Phase; D006801:Humans; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000097:blood / Q000378:metabolism*; D019272:Leukocyte Elastase; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology; D010196:Pancreatic Elastase / Q000097:blood* / Q000187:drug effects; D010919:Placebos; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D013997:Time Factors
D005230:Fatty Acids, Nonesterified; D005395:Fish Oils; D007375:Interleukin-1; D008070:Lipopolysaccharides; D010919:Placebos; D017392:Thiobarbituric Acid Reactive Substances; D010196:Pancreatic Elastase; D019272:Leukocyte Elastase