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Age-related alterations in cultured human fibroblast membrane structure and function
Mechanisms of Ageing and Development
|June 1, 1984
Summary
Cellular membranes from older human fibroblasts show increased fluidity and altered lipid composition, suggesting structural changes with age. These findings highlight age-related modifications in cell membrane properties.
Area of Science:
- Cellular Biology
- Biochemistry
- Gerontology
Background:
- Cellular membrane structure and function are critical for cell viability.
- Aging is associated with various physiological changes, including alterations in cellular components.
- Understanding age-related changes in cell membranes is crucial for comprehending the aging process.
Purpose of the Study:
- To investigate structural alterations in plasma membranes, microsomes, and mitochondria of cultured human fibroblasts as a function of donor age.
- To determine if changes in membrane enzyme activities, lipid composition, and fluidity occur with increasing donor age.
Main Methods:
- Isolated plasma membranes, microsomes, and mitochondria from cultured human fibroblasts of varying donor ages were analyzed.
- Membrane enzyme activities, including (Na+, K+)-ATPase, NADPH cytochrome c reductase, and succinate cytochrome c reductase, were measured.
- Lipid composition (cholesterol/phospholipid ratio, fatty acid saturation) and membrane fluidity (using fluorescence probes like trans-parinaric acid and 1,6-diphenyl-1,3,5-hexatriene) were assessed.
Main Results:
- While enzyme activities showed variations, they were not statistically significant with age.
- The cholesterol/phospholipid ratio decreased in microsomes, and the phosphatidylcholine/phosphatidylethanolamine ratio increased in all membrane fractions with age.
- Fluorescence probe data indicated increased membrane fluidity (decreased anisotropy) in plasma membranes, microsomes, and mitochondria with increasing donor age.
Conclusions:
- Cultured human fibroblast membranes exhibit increased fluidity and altered lipid composition, specifically changes in the cholesterol/phospholipid and fatty acid saturation ratios, with increasing donor age.
- These structural alterations suggest a functional impact on cellular processes in aging.
- The study provides evidence for age-dependent modifications in the biophysical properties of cellular membranes.