A retinal pigment epithelial cell-derived growth factor(s)

Area of Science:

• Ophthalmology
• Cell Biology
• Biochemistry

Background:

• Proliferative vitreoretinopathy (PVR) involves the proliferation of retinal pigment epithelial (RPE) cells, fibroblasts, and glial cells.
• Identifying the factors driving this proliferation is key to understanding PVR pathogenesis.

Purpose of the Study:

• To investigate whether cultured RPE cells produce factors that stimulate the growth of RPE cells, fibroblasts, and glial cells.
• To characterize the nature of this RPE-derived growth-promoting activity.

Main Methods:

• Cultured RPE cells were used to generate conditioned media.
• The effect of conditioned media on cell proliferation (cell number) and DNA synthesis (thymidine incorporation) of RPE cells, astrocytes, and corneal fibroblasts was assessed.
• Preliminary biochemical characterization of the growth-promoting activity was performed.

Main Results:

• RPE-conditioned media significantly increased the proliferation of RPE cells (110%), astrocytes (105%), and corneal fibroblasts (360%) compared to controls.
• Increased cell numbers were attributed to stimulated DNA synthesis.
• The growth-promoting activity was found to be heat stable, stable at extreme pH, nondialyzable, and partially trypsin sensitive.

Conclusions:

• Cultured RPE cells secrete growth factor(s) that promote the proliferation of RPE cells, astrocytes, and corneal fibroblasts.
• This RPE-derived factor appears to primarily target fibroblasts but also stimulates RPE and astrocyte growth.
• These findings suggest a significant role for RPE-secreted factors in the cellular mechanisms underlying proliferative vitreoretinopathy.