Relationship between cell replication and volume in senescent human diploid fibroblasts

Area of Science:

• Cell Biology
• Gerontology
• Biophysics

Background:

• Cell replication rate and volume distribution are early indicators of changes in human diploid cells.
• Understanding these parameters is crucial for studying cellular aging and health.

Purpose of the Study:

• To investigate the relationship between cell population doubling time and cell volume in cultured human diploid fibroblasts.
• To determine if cell growth rate influences cell size.

Main Methods:

• Standardized cell volume measurements in WI-38 cells, controlling for enzyme treatment, temperature, and growth stage.
• Compared cell volumes of rapidly replicating cells with slower-replicating cell populations (trisomic-21 fibroblasts, fetal skin fibroblasts).
• Induced changes in cell volume by altering serum concentration, incubation temperature, and DNA synthesis inhibition; separated senescent cells by volume.

Main Results:

• A close correlation was observed between cell population doubling time and cell volume in WI-38 cells.
• Slower-replicating cell populations exhibited larger cell volumes compared to faster-replicating controls.
• Reduced serum concentration, lower incubation temperature, and DNA synthesis inhibition all led to larger cell volumes.
• Senescent cells, characterized by the largest modal cell volumes, contained the highest proportion of slow or non-replicating cells.

Conclusions:

• An inverse relationship exists between growth rate and cell volume in cultured human diploid fibroblasts.
• Cellular aging and reduced replication are associated with an increase in cell size.