two months pass...
8. 15-JUN-2005
Encapsulated Islet Cell Transplants Avoid Host Immune Rejection
NEW YORK (Reuters Health) - A technology that has been under development for several years -- encapsulating islets cells with polyethylene glycol -- may soon obviate the need for immunosuppression in islet cell transplantation, according to a presentation Saturday at the American Diabetes Association's 65th Annual Scientific Sessions in San Diego, California.
The net result will be effective control of blood glucose levels in patients with insulin-dependent diabetes without the danger of hypoglycemia or graft rejection, lead presenter Dr. David Scharp told Reuters Health. Dr. Scharp is chief scientific officer and executive vice president of research and development at Novocell, Inc. in Irvine California.
By coating cells with polyethylene glycol, "immune cells cannot contact the graft and graft cells cannot contact the host, but they're wide open for exchange of insulin and glucose," he explained.
His group's research was conducted in diabetic baboons in which coated islet cells were injected subcutaneously. The only immunosuppression provided was a low dose of cyclosporine for 30 days.
In a group of 16 baboons, 15 showed significant reductions in hemoglobin A1c, average and fasting blood glucose, glycemic excursions and insulin requirements. Five of eight recipients were insulin-independent at 3 months after transplantation, as were two of eight recipients in a second group tested at 6 months.
So far, three treated animals have achieved insulin independence for 14 to 20 months before they were sacrificed.
Histological examination of the subcutaneous implant sites revealed little immune reactivity and increased capillaries.
"We know that islets cells can't live indefinitely outside of the pancreas and have to be replaced," Dr. Scharp said. "The coating is biodegradable so that about the time the islets would be failing in the patient the coating will be broken down and cleared in the kidney."
The investigators have also shown that the animals can be re-treated safely after the initial graft has failed. "So we should be able to do multiple implants safely without immunosuppressive drugs and eliminate diabetes altogether or come close to that," the researcher added.
Current limitations imposed by the restricted number of available cadaver donors means that only a fraction of eligible patients could be treated with this technique. For that reason, Novocell is working with a partner company to develop PEG-coated islet cells from embryonic stem cells, Dr. Scharp noted, which potentially could provide transplantable islets for any suitable candidate.
He expects a phase I/II safety and efficacy clinical trial to be started within the next several months.
2005 Reuters Health
― jack cole's skeletal remains found at the bottom of a ravine (jackcole), Wednesday, 22 June 2005 17:02 (twenty years ago)
1. the longest day of the year
2. my Japanese vegetable garden (yamaimo, daikon, tororo, nasu, kyuru)
3. being home for the first proper weekend in almost 3 months.
4. Vancouver, BC
5.
Dance, Dance, Dance6. being best man in a wedding next month
7. hearing Malo - "Suavecito" in a late night, balmy cabride
8. .5 mile warm-up, 4 miles through the park to the beach, .5 mile cool-down in under 45 minutes (+15 minute train ride home).
9.
Little Boy in NYC
10. Teas Tea
― gygax! (gygax!), Wednesday, 22 June 2005 17:30 (twenty years ago)