Porcine pancreatic islets were microencapsulated in alginate-polylysine-alginate capsules and transplanted intraperitoneally into nine spontaneously diabetic monkeys. After one, two, or three transplants of 3-7 x 10(4) islets per recipient, seven of the monkeys became insulin independent for periods ranging from 120 to 804 d with fasting blood glucose levels in the normoglycemic range. Glucose clearance rates in the transplant recipients were significantly higher than before the graft administration and the insulin secretion during glucose tolerance tests was significantly higher compared with pretransplant tests. Porcine C-peptide was detected in all transplant recipients throughout their period of normoglycemia while none was found before the graft administration. Hemoglobin A1C levels dropped significantly within 2 mo after transplantation. While ketones were detected in the urine of all recipients before the graft administration, all experimental animals became ketone free 2 wk after transplantation. Capsules recovered from two recipients 3 mo after the restoration of normoglycemia were found physically intact with enclosed islets clearly visible. The capsules were free of cellular overgrowth. Examination of internal organs of two of the animals involved in our transplantation studies for the duration of 2 yr revealed no untoward effect of the extended presence of the microcapsules.
Y Sun, X Ma, D Zhou, I Vacek, A M Sun
Guidelines: The Editorial Board will only consider letters that we deem relevant and of interest to our readers. We will not post data that have not been subjected to peer review, nor will we post letters that are essentially a reiteration of another letter. All accepted letters will be posted on our website within one week of acceptance. We reserve the right to edit any letter for length, content, and clarity. Authors of all accepted letters will be asked to preview any changes. Authors will be notified by e-mail if their letters were not accepted. As this is a final decision, no appeals will be considered.
Specific requirements: All letters must be 400 words or fewer. You may enter the letter as plain text or HTML. The author's name and e-mail address are required, and will be posted with the letter. All possible conflicts of interest must be noted, even if they are not posted. If you wish to include a figure (keep in mind that non-peer-reviewed data will not be posted), please contact the editors directly at firstname.lastname@example.org.