Researchers in Rice’s Department of BioSciences, propose that degeneration, at the cellular level, occurs in two distinct phases that are marked by very different activities of protein signaling pathways that regulate basic cell functions.

“We would like clinicians and other researchers to understand that the two phases of degeneration represent distinct entities, with distinct alterations in signaling pathways that have distinct effects on disease pathology,” Stern said. “In other words, we think that patients need to be treated differently depending on which phase they are in.”

Stern and McNew’s diagram shows how the activity of key cell signaling proteins either increases or decreases at the onset of degeneration, ultimately bringing about oxidative stress. Oxidative stress then brings about the second phase of the condition, during which degeneration occurs, where the signaling proteins implicated in the first phase behave in a completely different way.