Cells isolated from human umbilical cord tissue produce molecules that help retinal neurons from the eyes of rats grow, connect and survive, a new study reveals.

The findings implicate one family of molecules in particular -- thrombospondins -- that may have therapeutic potential for the treatment of degenerative eye diseases.

"By learning more about how these cells work, we are one step closer to understanding the disease states in which these cells should be studied," said lead researcher Cagla Eroglu from Duke University Medical Centre.

Umbilical cord tissue-derived cells (hUTC) differ from umbilical cord blood cells in that they are isolated from cord tissue itself, rather than the blood.

The Duke team used an established cell culture system to determine whether and how the hUTCs might affect the growth of neurons isolated from the retinas of rat eyes.

In an experimental set-up that allowed the two types of cells to bathe in the same fluid without coming into physical contact, retinal neurons in a bath with hUTCs formed new connections between neurons called synapses, and they sprouted new 'neurites' - tiny branches that lead to additional connections.

These cells also survived longer than rat neurons placed in a bath lacking the umbilical cord tissue-derived cells.

Blocking thrombospondins was found to reduce new connections among neurons.

"It's exciting that thrombospondins had a really strong effect on neurite outgrowth," said Eroglu.