In "a first step toward engineering of an artificial beta cell" totreat diabetes, Texas researchers have published results on acell derived from mouse pituitary gland that can respond toblood levels of glucose by secreting insulin.
Diabetics are unable to produce insulin in response to risingblood sugar. Last month, two companies reported progress indevising small capsules that could potentially replace diabetics'damaged pancreases. Yet pancreas cells, which the capsulescontain, would be difficult to supply in quantities needed forhuman therapy, biochemist and diabetes researcherChristopher Newgard told BioWorld.
Work at the University of Texas Southwestern Medical Centerin Dallas has provided an alternative to pancreases. Newgard'steam has inserted a gene that allows mouse pituitary cells,previously engineered by others to secrete insulin, to respondproperly to blood glucose.
The cells still require fine-tuning, Newgard said. The co-secretion of mouse ACTH, another hormone, in response toblood glucose signals, may or may not cause a problem. Also,the cells need to be made less trigger-happy; they now respondto lower glucose concentrations than experienced in normalphysiology, Newgard said. He said a correction is about to betested.
Newgard said potential corporate collaborators have alreadyapproached the university, which has filed to patent the cells.
Last month, CytoTherapeutics Inc. of Providence, R.I., reportedthat it has seeded rat islet cells into hollow tubes of acryliccopoymer. Planted under the skin of diabetic rats, the tissuewas protected from rejection and supplied enough insulin tokeep the rats' blood sugar at normal levels for at least 60 days.
And BioHybrid Technologies Inc. has showed that cross-speciesimplants can work without rejection, using an encapsulatingstrategy similar to that of CytoTherapeutics. The Shrewsbury,Mass., subsidiary of W.R. Grace & Co. uses W.R. Grace's XM-50acrylic polymer, which allowed tissue to survive in theperitoneal cavity and provide insulin to diabetic rats for atleast a month.
-- Roberta Friedman, Ph.D. Special to BioWorld
(c) 1997 American Health Consultants. All rights reserved.