Functional changes in aging polymorphonuclear leukocytes.
BACKGROUND
Previous studies from our laboratory have shown that the expression of L-selectin on polymorphonuclear neutrophils (PMN) decreases as the cell ages in the circulation and that these older PMN have more fragmented DNA and show morphological features of apoptosis.


RESULTS
The present study was designed to compare the functional capabilities of PMN expressing low levels of L-selectin (L-selectin[low]) and the total population of PMN they were isolated from (L-selectin[mixed]). The results show no difference of the baseline filamentous actin (F-actin) content between PMN expressing low and high levels of L-selectin. However, the ability of L-selectin(low) PMN to assemble F-actin was impaired after stimulation by n-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) (1 nmol/L fMLP: P<.02, 10 nmol/L fMLP: P<.01). The ability of L-selectin(low) PMN to change shape when stimulated (10 nmol/L fMLP) was also decreased (P<.05). Filtration studies showed no difference in baseline deformability between L-selectin(low) and L-selectin(mixed) leukocytes, but the L-selectin(low) cells showed a decreased ability to stiffen after fMLP stimulation (P<.05). L-selectin(low) cells demonstrated a decreased ability to migrate toward a chemoattractant (1, 3, and 10 nmol/L fMLP) (P<.004) but have an enhanced ability to upregulate CD18 (P<.00002) and produce hydrogen peroxide (P<.00004).


CONCLUSIONS
We conclude that PMN undergo substantial functional changes as they age in the circulation.
Tanji-Matsuba
K
K
University of British Columbia, Pulmonary Research Laboratory, St Paul's Hospital, Vancouver, Canada.
van Eeden
S F
SF
Saito
Y
Y
Okazawa
M
M
Klut
M E
ME
Hayashi
S
S
Hogg
J C
JC
D000199:Actins / Q000032:analysis; D000818:Animals; D017209:Apoptosis; D018821:CD18 Antigens / Q000032:analysis; D016922:Cellular Senescence / Q000502:physiology; D005260:Female; D006861:Hydrogen Peroxide / Q000378:metabolism; D066298:In Vitro Techniques; D019041:L-Selectin / Q000032:analysis; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D011817:Rabbits
D000199:Actins; D018821:CD18 Antigens; D019041:L-Selectin; D009240:N-Formylmethionine Leucyl-Phenylalanine; D006861:Hydrogen Peroxide