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Age-related decline in lysosomal enzyme release from polymorphonuclear leukocytes after
Abstract:
Aging is assumed to decrease lysosomal enzyme release from polymorphonuclear leukocytes (PMN). A synthetic chemotactic peptide, N-formyl-methionyl-leucyl-phenylalanine (fMet-Leu-Phe) was utilized to stimulate enzyme release of PMN from 45 human subjects, 21 males and 24 females, ranging in age from 22-83 yr old. Results of the studies showed no sex differences in the stimulation of enzyme release for either age group. However, stimulation was found to significantly decline in both males and females over 50 yr old compared to subjects under 50 yr old. The linear formulae for beta-glucuronidase, beta-galactosidase and lysozyme in male subjects were Y = 6.5X + 617.2, Y = -1.9X + 311.5 and Y = -1.9X + 327.3 with correlation coefficient of -0.685, -0.352 and -0.401, respectively. The linear formulae in females were Y = -5.2X + 536.6, Y = -3.0X + 340.6 and Y = -1.7X + 333.6 with correlation coefficient of -0.582, -0.303 and -0.462, respectively. These findings suggest that there was an age-related decline of response to the stimulant, fMet-Leu-Phe.
Insights
Aging significantly reduces lysosomal enzyme release from polymorphonuclear leukocytes (PMN). This age-related decline in PMN response to chemotactic peptides was observed in both sexes over 50 years old.
Area of Science:
- Immunology
- Gerontology
Background:
- Lysosomal enzyme release from polymorphonuclear leukocytes (PMN) is crucial for immune responses.
- Aging is often associated with altered immune cell function.
Purpose of the Study:
- To investigate the effect of aging on lysosomal enzyme release from PMN stimulated by a synthetic chemotactic peptide.
- To determine if there are sex differences in this age-related response.
Main Methods:
- Stimulation of PMN from 45 human subjects (21 males, 24 females, aged 22-83) using N-formyl-methionyl-leucyl-phenylalanine (fMet-Leu-Phe).
- Quantification of lysosomal enzyme release (beta-glucuronidase, beta-galactosidase, lysozyme).
- Statistical analysis to compare enzyme release between age groups and sexes, and to establish linear regression models.
Main Results:
- No significant sex differences were observed in enzyme release.
- A significant decline in stimulated enzyme release was found in both males and females over 50 years old compared to those under 50.
- Linear regression models showed a negative correlation between age and enzyme release for specific enzymes in both sexes.
Conclusions:
- The study demonstrates an age-related decline in the responsiveness of PMN to the chemotactic peptide fMet-Leu-Phe.
- This decline in lysosomal enzyme release suggests an impaired immune function in older adults.
- The findings highlight the impact of aging on innate immune cell activity.