Increased mucosal production of granulocyte colony-stimulating factor is related to a delay in neutrophil apoptosis in Inflammatory Bowel disease.
Tissue accumulation of polymorphonuclear neutrophils (PMN) in Inflammatory Bowel disease (IBD) might be, in part, due to a delay in apoptotic processes associated with the effects of their specific growth factors and inflammatory cytokines. We addressed this hypothesis by examining the activity of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage CSF (GM-CSF) in the organ culture supernatants of colonic mucosal specimens and their regulatory effects on PMN apoptosis in patients with IBD. The contents of G-CSF and GM-CSF in the supernatants were measured by the enzyme-linked immunosorbent assays and PMN apoptosis was evaluated by acridine orange/ethidium bromide staining, respectively. Mucosal specimens obtained from patients with active IBD exhibited higher levels of G-CSF and GM-CSF activity than controls. Notably, the levels of G-CSF activity were approximately 1000-fold higher than those of GM-CSF activity. Freshly isolated PMN showed a time-related increase in the proportion of cells with characteristic features of apoptosis when they were incubated with the culture medium alone and exposure of PMN to recombinant G-CSF and GM-CSF caused a concentration-dependent inhibition of apoptosis. Incubation of PMN with the supernatants from patients with active IBD induced an inhibitory effect on PMN apoptosis; this effect was abrogated to a significant degree by pre-incubation of the supernatants with anti-G-CSF serum. This study suggests that PMN apoptosis may be delayed under the influence of soluble mediators, especially G-CSF, in the microenvironment of IBD-affected mucosa, thus providing possible mechanisms for tissue accumulation of PMN in IBD.
First Department of Internal Medicine, Nagoya University School of Medicine, Japan.
K
K
Ina
K
K
Kusugami
T
T
Hosokawa
A
A
Imada
T
T
Shimizu
T
T
Yamaguchi
M
M
Ohsuga
K
K
Kyokane
T
T
Sakai
Y
Y
Nishio
Y
Y
Yokoyama
T
T
Ando
D000165:Acridine Orange / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis; D017077:Culture Media, Conditioned / Q000494:pharmacology; D046508:Culture Techniques; D016207:Cytokines / Q000494:pharmacology; D004996:Ethidium / Q000378:metabolism; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000378:metabolism*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000378:metabolism / Q000473:pathology*; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000166:cytology* / Q000187:drug effects
D017077:Culture Media, Conditioned; D016207:Cytokines; D016179:Granulocyte Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D004996:Ethidium; D000165:Acridine Orange