Comments on: LCT Microcapsules will be Available Soon; Islet Sheet Obsolete? http://www.solvingdiabetes.org/2009/07/09/lct-microcapsules-will-be-available-soon-islet-sheet-obsolete/ A site dedicated to solving diabetes. Sat, 14 Aug 2010 23:12:33 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Scott King http://www.solvingdiabetes.org/2009/07/09/lct-microcapsules-will-be-available-soon-islet-sheet-obsolete/comment-page-1/#comment-36 Scott King Wed, 15 Jul 2009 16:42:48 +0000 http://www.solvingdiabetes.org/?p=298#comment-36 We don't think that is possible. We can make Islet Sheets so strong that dividing cells cannot burst out. And, in addition, the cells would be allo or xeno and so rapidly rejected by the host. (Metastatic cells are autologous.) We don’t think that is possible. We can make Islet Sheets so strong that dividing cells cannot burst out. And, in addition, the cells would be allo or xeno and so rapidly rejected by the host. (Metastatic cells are autologous.)

]]> By: JPMarat http://www.solvingdiabetes.org/2009/07/09/lct-microcapsules-will-be-available-soon-islet-sheet-obsolete/comment-page-1/#comment-29 JPMarat Sun, 12 Jul 2009 18:58:41 +0000 http://www.solvingdiabetes.org/?p=298#comment-29 If the encapsulated islets undergo a malignant transformation and metastasize before the capsule can be withdrawn -- which might well happen, since many cancers are not identified until after metastasis -- then this seems to be a risk which would be difficult to eliminate. If the encapsulated islets undergo a malignant transformation and metastasize before the capsule can be withdrawn — which might well happen, since many cancers are not identified until after metastasis — then this seems to be a risk which would be difficult to eliminate.

]]> By: Scott King http://www.solvingdiabetes.org/2009/07/09/lct-microcapsules-will-be-available-soon-islet-sheet-obsolete/comment-page-1/#comment-21 Scott King Thu, 09 Jul 2009 17:22:16 +0000 http://www.solvingdiabetes.org/?p=298#comment-21 Since you sent your question, JP, LCT announced the establishment of a Russian subsidiary that expects to make the product available at their new St. Petersburg clinic in October 2010. (It is refreshing to know there is a regulatory regime on this earth that permits you to know more than a year in advance when your product will be available to patients.) Therefore it is very likely that the LCT product (DIABECELL®) will be on the market long before the Islet Sheet. We consider the Islet Sheet to be the second generation islet encapsulation device. Why is a second generation product needed? The major advantage of the Islet Sheet compared with microcapsules is that the Islet Sheet can be retrieved and replaced, an additional layer of safety. Islet containing devices are literally alive, and the cells inside are responding to the environment with varying secretion of hormones. (There is no comparable product in routine medical use; this is a fundamentally new medical product category.) As you observe JP, these cells are not getting nutrients through normal vascularization but rather through diffusion. We are uncertain of the long term effects of cells receiving all their nutrients by diffusion rather than vascularization. We do know that they are exempt from normal immune surveillance. (Immune cells travel mostly through the blood stream and therefore would not be able to reach islets in Islet Sheets.) Some risk remains that the encapsulated cells might transform into malignant cells or teratomas. That’s why it is so important that the device can be removed. (This is especially important for stem cell islets, where the risks seem high.) We have already removed Islet Sheets even following an intentionally induced local tissue reaction. That is why I am convinced that the Islet Sheet is the encapsulation device of choice, because the Islet Sheet is demonstrably safer. Put it this way. If the islets function well in both microcapsules and the Sheet, and only one can be removed, which one would you choose? Since you sent your question, JP, LCT announced the establishment of a Russian subsidiary that expects to make the product available at their new St. Petersburg clinic in October 2010. (It is refreshing to know there is a regulatory regime on this earth that permits you to know more than a year in advance when your product will be available to patients.) Therefore it is very likely that the LCT product (DIABECELL®) will be on the market long before the Islet Sheet.

We consider the Islet Sheet to be the second generation islet encapsulation device. Why is a second generation product needed?

The major advantage of the Islet Sheet compared with microcapsules is that the Islet Sheet can be retrieved and replaced, an additional layer of safety. Islet containing devices are literally alive, and the cells inside are responding to the environment with varying secretion of hormones. (There is no comparable product in routine medical use; this is a fundamentally new medical product category.) As you observe JP, these cells are not getting nutrients through normal vascularization but rather through diffusion. We are uncertain of the long term effects of cells receiving all their nutrients by diffusion rather than vascularization. We do know that they are exempt from normal immune surveillance. (Immune cells travel mostly through the blood stream and therefore would not be able to reach islets in Islet Sheets.) Some risk remains that the encapsulated cells might transform into malignant cells or teratomas. That’s why it is so important that the device can be removed. (This is especially important for stem cell islets, where the risks seem high.) We have already removed Islet Sheets even following an intentionally induced local tissue reaction. That is why I am convinced that the Islet Sheet is the encapsulation device of choice, because the Islet Sheet is demonstrably safer.

Put it this way. If the islets function well in both microcapsules and the Sheet, and only one can be removed, which one would you choose?

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