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Neutrophil migration, oxidative metabolism, and adhesion in elderly and young subjects
D Biasi1, A Carletto, C Dell'Agnola
1Institute of Patolgia Medica University of Verona, Italy.
Objective:
To evaluate neutrophil functions in the elderly.
Methods:
We investigated the PMN migration in vivo and PMN superoxide production and adhesion in response to a variety of compounds; PMN have been isolated both from blood and from a skin experimental exudate (obtained by Senn's skin window technique) of 25 normal elderly and of 25 normal young control subjects.
Results:
No difference was found in PMN migration in vivo (62.9 +/- 21.3 x 10(6) and 65.5 +/- 9.1 x 10(6) PMN/cm2/24 hours in elderly and young subjects respectively), neither were different the adhesion under basal condition and after some stimuli and the superoxide production in basal condition and in response to STZ and PMA in two groups. In elderly subjects superoxide production, in response to fMLP, markedly resulted lower than in young controls both by circulating PMNs (3.6 +/- 2.7 and 9.3 +/- 3.3 nMOLES O2-/10(6) PMN respectively, p < 0.0001) and by exudate PMNs (13.6 +/- 4.3 and 19.4 +/- 6 nMOLES O2-/10(6) PMNs respectively, p < 0.005).
Conclusion:
Many PMN functions in the elderly do not differ from young people, suggesting that the overall defense function of these cells is not affected by aging. The only parameter that we have found to be different between the two groups is the poor superoxide production after fMLP stimulus of PMNs. The stimulus- and function-specificity of this defect in PMNs from elderly subjects indicates the existence of a dysregulation of the signal transduction pathway distal to fMLP receptor and proximal to NADPH oxidase activation.
Insights
Neutrophil functions generally remain intact in the elderly. However, elderly individuals show reduced superoxide production in neutrophils when stimulated with fMLP, indicating a specific age-related defect.
Area of Science:
- Immunology
- Gerontology
Background:
- Neutrophils (PMN) are crucial immune cells.
- Aging can impact immune cell function, affecting host defense.
Purpose of the Study:
- To evaluate key neutrophil functions in elderly individuals compared to younger controls.
Main Methods:
- Investigated neutrophil migration, superoxide production, and adhesion in elderly and young subjects.
- Utilized Senn's skin window technique for exudate neutrophil isolation.
Main Results:
- Neutrophil migration and adhesion were similar between elderly and young groups.
- Superoxide production was comparable under basal conditions and with STZ/PMA stimuli.
- Elderly neutrophils exhibited significantly lower superoxide production in response to fMLP.
Conclusions:
- Most neutrophil functions are preserved in aging.
- A specific defect in fMLP-stimulated superoxide production exists in elderly neutrophils.
- This suggests a dysregulation in the signal transduction pathway in aging neutrophils.