But in the diabetic, insulin is injected outside the pancreatic portal circulation, usually subcutaneously, so it first travels to the general circulation and only later ends up in the liver. This means that even in a diabetic with a ‘perfect’ blood sugar level, there may remain a very significant degree of abnormality, since the insulin levels and the glucose levels in the various parts of the body are not physiological. All that is being tested as a substitute value for determining the patient’s ‘normality’ is arterial or venous blood from the general circulation, when what is in fact needed to measure the true physiological status of the patient is a full anatomical schematic showing how far the present glucose and insulin measures in each part of the body correspond to or diverge from the locally normal insulin and blood sugar distributions required by the local conditions, such as high or low energy use. The globally normal blood sugar level, which is now used, cannot give us the true picture in all its natural complexity.

This divergence between the normal anatomical variety of insulin and blood sugar and that in diabetic treated with insulin has never been measured, but may well explain why diabetics often feel less healthy than normal counterparts even when they have a normal blood sugar reading, or why many diabetics with excellent blood sugar control nonetheless experience complications. If the maldistribution rather than just the lack of insulin is an important factor in type 1 diabetes, then the implantation of an immunologically protected packet of porcine islet cells in the abdomen may omit an important aspect of what is needed to normalize diabetic physiology. But since the pancreas is a notoriously difficult area of the body to access for surgical interventions, if the porcine islet cell packet were to be implanted there in order more closely to replicate normal insulin distribution, the cost of the procedure would be many times higher than simply inserting it into the abdomen. Thus the number of patients treated would be so small — just because of the expense and limitation of available surgical facilities — that the gain in using pig rather than human cells to overcome the scarcity of the human cell supply might be seriously compromised.

Your concern about sub-optimal control is sound; when fasting euglycemia is not achieved, and control requires insulin injections, there are potential problems. Given the small molecule permeability and rapid diffusion kinetics , we believe that the Islet Sheet will be able to deliver euglycemia without insulin injections.