Shortly after the launch of Solving Diabetes we received a number of penetrating questions from “J P Marat”. With his permission the resulting dialogue with Scott King has been edited for inclusion in Straight Talk. “J P Marat” is the pen name of a diabetes researcher in Canada. The dialogue has been formatted to enable further dialogue from readers.
If the insertion of the encapsulation into the abdomen has to be repeated every few years, have you considered the problem of scarring and surgical adhesions from these repeated procedures? The abdomen is not a paper bag that you can cut open and tape up indefinitely without consequences.
Your concerns about the abdominal site have not been missed by us! First, the peritoneal cavity is really tough, according to surgeons. It can be used daily for peritoneal dialysis for years with no major ill effects. Second, implantation will be endoscopic which will minimize surgical trauma. Third, we are exploring the subcutaneous site as well. The abdominal site has metabolic advantages (portal insulin delivery) and the subcutaneous site has surgical advantages (less invasive). This will only be answered with animal studies.
Where I might part company from your views would be with respect to the dangers of peritonitis, if the peritoneum is used for implantation of the encapsulated cells. Although the analogy of peritoneal dialysis with encapsulated cell implants in the peritoneum is not exact, since patients on peritoneal dialysis usually perform four exchanges a day, the peritonitis incidence in patients having to access the peritoneum for renal dialysis is a significant problem, amounting to one case per patient per 14.7 months. (A. Davenport, “Peritonitis Remains the Major Clinical Complication of Peritoneal Dialysis,” Peritoneal Dialysis International, vol. 29, no. 3, p. 297 (2009)) Since peritonitis can be lethal without rapid intervention, this is a serious risk.
Well, you are right; the peritoneal dialysis comparison is flawed. The history of microencapsulation is not encouraging. Capsules that are known to induce an inflammatory response have been reported to cause serious abdominal problems including adhesions.
To be honest we are less confident about solving this problem than many of the other problems we face. All I can say is that we are encouraged by what we have seen so far in dogs and small mammals. We’ll certainly look at it carefully.