Correlations between membrane viscosity, serum cholesterol, lymphocyte activation and aging in man

Area of Science:

• Immunology
• Biochemistry
• Gerontology

Background:

• Aging is associated with altered immune function.
• Changes in cell membrane properties may influence immune cell behavior.
• Serum cholesterol levels and membrane characteristics are known to change with age.

Purpose of the Study:

• To investigate the relationship between aging, serum cholesterol, lymphocyte membrane microviscosity, and immune cell stimulation.
• To determine if changes in membrane microviscosity correlate with reduced lymphocyte responsiveness in older individuals.

Main Methods:

• Measurement of membrane microviscosity in peripheral blood lymphocytes.
• Analysis of serum cholesterol to phospholipid mole ratio.
• Assessment of lymphocyte stimulation response to concanavalin A.

Main Results:

• A direct correlation was observed between serum cholesterol/phospholipid ratio and lymphocyte membrane microviscosity.
• Both membrane microviscosity and serum cholesterol/phospholipid ratio increased with age.
• Increased membrane microviscosity correlated with decreased lymphocyte response to concanavalin A stimulation.

Conclusions:

• Elevated lymphocyte membrane microviscosity is a significant factor contributing to reduced lymphocyte proliferation in aging.
• Changes in membrane properties, particularly microviscosity, play a key role in age-related immune decline.