Normalisation of growth hormone hypersecretion in uraemic diabetics and non-diabetics. Studies with artificial pancreas and artificial kidney.
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Evolution of the Artificial Pancreas: Components and Integration-CGMs, Insulin, and AP Systems.
The landmark Diabetes Control and Complications Trial (DCCT) showed that glucose control is critical to reducing the risk of diabetes-related complications. This chapter outlines a series of innovations and investigations that followed the DCCT, aimed at minimizing the risk of hypoglycemia while further improving glucose control. The chapter presents an example of innovations in wired enzyme technology that facilitated the movement from capillary glucose monitoring to continuous glucose monitoring (CGM) and ultimately, the first-factory calibrated CGM system. The next glycemic management innovation was to connect CGM data to an insulin pump containing an algorithm able to adjust insulin delivery based on the changing glucose levels and trends. The key features of automated insulin delivery (AID) systems, currently approved in the United States, are presented. The AID summary table includes type of pump, type and function of the insulin delivery algorithm, the data management system, and the indications for use. The next section explores the innovation of alternative routes of insulin delivery to move toward the goal of a fully automated insulin delivery system. The main trials in developing and implementing an implantable intraperitoneal programmable system are summarized. The last section explores if sensor input in addition to glucose levels such as continuous sensing of ketone, lactate, or insulin levels may provide valuable feedback to move us closer to a fully autonomous AID system. Much of this diabetes innovation and investigation work has been supported by the National Institute of Diabetes and Digestive and Kidney Diseases over that last 75 years.
Humans↗
[The endocrine pancreas. From the isolated islet to the "artificial pancreas" (author's transl)].
The endocrine function of the pancreas consists of the promotion of storage of nutritive substances after meals through the liberation of insulin and to guarantee the mobilization of this food energy through the secretion of glucagon during fasting. Increased hormone production may result from tumors of the islet cells (insulin: insulinoma; glucagon: glucagonoma; gastrin: Zollinger-Ellison syndrome). An absolute or relative insulin deficiency is a characteristic of diabetes mellitus, in which a relative hyperglucagonemia is also of possible pathophysiological significance. This increased secretion of glucagon can be suppressed by somatostatin. While the clinical application of somatostatin in diabetes mellitus seems problematic at present, the use of a glucose-controlled system of insulin infusion ("artificial pancreas") makes possible a metabolic state approaching the healthy condition.
Adult↗
Control of blood glucose in diabetics using an artificial pancreas.
Studies have been performed using an on-line computer system programmed for blood gucose control of insulin and dextrose infusion (artificial pancreas). The aim of these studies was to test performance of the artificial pancreas and to suggest directions for future optimisation. Blood glucose stabilisation studies of diabetic volunteers were extended throughout the day and included three main meals and light exercise periods. Monitoring of blood glucose profiles of the same diabetics after depot insulin were performed on a separate occasion for comparison. The presence of insulin antibodies did not impair operation of the artificial pancreas. Most of the insulin infused by the artificial pancreas was to initially correct hyperglycaemia with relatively little required to subsequently maintian euglycaemia. The afternoon intra-meal average infusion rate was 0-9 U/hr. It is suggested that correction of fasting hyperglycaemia and maintenance of euglycaemia in diabetics be treated as separate control problems for the artificial pancreas. The overall ability of the artificial pancreas to control blood glucose to a degree not attainable by conventional insulin therapy is confirmed, in this case under conditions which include patient activity.
Adult↗
Use of an artificial pancreas as a tool to determine subcutaneous insulin doses in juvenile diabetes.
The present study was undertaken to examine the feasibility of determining the most appropriate subcutaneous insulin treatment in unstable diabetes on the basis of the circadian hormonal profile delivered by an artificial pancreas. The metabolic control of 11 brittle diabetic subjects, as assessed by the M value and the MAGE index (used as indexes of blood glucose control and of glycemic fluctuations, respectively), was compared during a 5-day period before and after a 24-h connection to the artificial pancreas. The usual insulin treatment was continued to that day. Examination of the insulin pattern revealed by the artificial pancreas suggested that a valid scheme for subsequent treatment should consist of two daily injections of a mixture of short-acting and intermediate-acting insulins, which was administered to the patients beginning with the injection given after the artificial pancreas onwards. The new insulin regimen was characterized by a total daily dose that increased from 0.93 +/- 0.10 to 1.20 +/- 0.10 U/kg body weight (mean +/- SEM; P less than 0.005) as well as by a higher proportion of the dose given as regular insulin (37.1 +/- 6.9% before vs. 56.0 +/- 2.1% after; P less than 0.05). These changes led to a better control of blood glucose in 10 patients, as evidenced by a decrease of both the M value and the mean of all blood glucose levels. The mean MAGE index was not decreased, however, by the new insulin program, thereby suggesting that the lability of the disease remained unabated. These results indicate that subcutaneous treatment consisting of two daily injections of regular and intermediate-acting insulins and comprising 50 to 60% of the former could improve the metabolic control in unstable diabetes. The artifical pancreas provided a rapid and simple means to determine the appropriate doses for each type of insulin.
Adult↗
The use of the artificial pancreas in uremic diabetic patients.
Maintenance hemodialysis and renal transplantation are increasingly used for treating diabetic patients with end-stage renal failure. The use of the artificial pancreas is able to prevent large blood glucose fluctuations in these patients with atherosclerosis, advanced retinopathy or neuropathy in which hyper- and hypoglycemia are potentially deleterious. For this purpose, we have developed and are utilizing an artificial pancreas easily utilizable without special training by the staff of a dialysis unit. This artificial pancreas uses a polarographic glucose electrode with a fast response time (45 to 90 seconds), a terminal display for operator communication, and a continuous digital and analogyl display for control of the running operation. There is also a printer to display in tabular and graphical form the values at any time during the operation. In this preliminary study, 7 patients have been studied: five under repetitive hemodialysis for four hours, 3 times a week; one treated by peritoneal dialysis for 12 hours, twice a week and one controlled during, and 48 hours after, renal transplantation. The macroscopic pancreas normalizes blood glucose under these circumstances, helps in a better understanding of blood glucose homeostasis in uremic patients under dialysis, leads to a more precise evaluation of insulin needs, may help to improve the nutritional status of the patients, and has an educational value for the patient and the medical staff.
Artificial Organs↗
The external artificial pancreas: an instrument to induce remissions in severe recent juvenile diabetes. Comparison with a preprogrammed insulin infusion system.
Remission of juvenile insulin-dependent diabetes is a rare, temporary, and partial phenomenon which seems to be related to an improvement of the residual insulin secretion supported by prompt and rigorous insulin therapy. Thus, remissions allowing the replacement of insulin by oral drugs were attempted in 23 insulin dependent ketotic juvenile diabetics (age 10 +/- 2 years) of recent onset (apparent duration of diabetes 71 +/- 5 days) treated by an external artificial pancreas during 5 +/- 1 days and compared with 10 control diabetics treated by a less effective technique (preprogrammed insulin pump without feedback control) during 6 +/- 1 days. 18 (78%) remissions of long duration (1-26 months) occurred after artificial pancreas compared with 3 (30%) in the control group. Measurement of daily urinary C-peptide excretion confirmed the improvement of the residual insulin secretion in patients with insulin-induced remissions. Thus, the excellent blood glucose control given by an artificial pancreas seems necessary to lead to much more frequent remissions of diabetes than usually reported.
Acute Disease↗
[Study of the possibility of using the "artificial pancreas" in the treatment of diabetes mellitus].
A short survey of the literature data on the use of an artificial pancreas in the treatment of patients suffering from diabetes mellitus is presented. These data point to the high efficacy of the artificial pancreas in diabetic patients, this confirming the author's personal observations.
Blood Glucose↗
[Remission of diabetes during conventional insulin therapy or therapy controlled by use of an artificial pancreas].
12 recent acute-onset ketotic juvenile diabetics were optimally treated during 5 +/- days by means of an external artificial pancreas. Remission of diabetes occurred in 9 patients (75%). In a comparative group of 28 patients treated by conventional subcutaneous insulin, only 3 (11%) steady remissions were obtained. In a third group of 6 patients treated by insulin infusion without feed-back control, only 1 remission (17%) was obtained. The difference between these two groups and the first group (patients treated by the artificial pancreas) is significant (p less than 0.01). Urinary C-peptide/blood glucose ratio showed a steady improvement of insulin secretion during the remission period. At this time, actuarial analysis shows that the number of patients still in remission decreases during the first 10 months but seems to stabilize after this period. Duration of our remissions is equal to the duration of the "spontaneous" remissions taken from the literature. New treatment able to sustain the residual insulinsecretion during the remission phase (with presently can be induced frequently with our technique) are still to be found.
Adolescent↗
Dynamic study of the blood viscosity of insulin-dependent diabetics by means of an artificial pancreas.
The blood viscosity of 15 insulin-dependent, poorly controlled, diabetic subjects was determined by using a microviscosimeter at low shear rates, with cylindrical cuvettes of the Couette type. It was found that the blood viscosity of these diabetics was more elevated than that of control patients (p less than 0.001). In ten diabetics, the return to a strict metabolic control over a period of more than 24 h by means of an artificial pancreas resulted in a significant systematic lowering of blood viscosity. These results suggest that the metabolic control of diabetes influences blood viscosity, and they underline the importance of an artificial pancreas for the dynamic study of the factors affecting blood viscosity during the course of diabetes.
Adolescent↗
Bioengineering aspects of the artificial pancreas.
In this paper, results of work aimed at the development of artificial beta-cells are presented. An electrolytically driven pump is considered to be a proper device for insulin injection. The transient characteristics of the simplified version of such a pump make it suitable for application in open-loop devices. Methods for electrical control of the injection rate of this pump for application in closed-loop artificial beta-cells are given. An essential component of a closed-loop artificial beta-cell is a glucose sensor. A modified version of the glucose sensor has been developed and its performance is described. Considerations of some control problems related to the artificial pancreas are briefly discussed.
Animals↗
[Artificial pancreas: study methods and control of glycemia equilibrium in diabetic patients].
The artificial endocrine pancreas or artificial beta cell, consists of a continuous blood glucose monitoring system, a computered set-up which responds to glycemia and the hormone delivery system. This system provides a technique which can completely normalize blood glucose concentration in diabetic patients, during both food assumption and after. This paper deals with the characteristics of the artificial beta cell, its possible applications and its limits.
Artificial Organs↗
Artificial pancreas using living beta cells:. effects on glucose homeostasis in diabetic rats.
An artificial pancreas consisting of beta cells cultured on synthetic semipermeable hollow fibers was tested in rats with alloxan-induced diabetes. When implanted ex vivo as arteriovenous shunts in the circulatory system these devices lowered concentrations of plasma glucose from 533 to between 110 and 130 milligrams per 100 milliliters, increased concentrations of plasma insulin, and restored intravenous glucose tolerance tests essentially to normal.
Animals↗
[Variations in blood viscosity of insulin-dependent diabetic subjects controlled by artificial pancreas (author's transl)].
A study of blood viscosity at 3 rates of determination (0.232-0.348 and 1.16 sec-1) in insulin-dependent diabetic subjects controlled by artificial pancreas, shows a reduction in this parameter after 30 hours of feed back control. The relationship between these variations, the mechanical cohesion of the agglutinated red cells, and the deformability of these structures are discussed.
Artificial Organs↗
Sustained insulin-induced remissions of juvenile diabetes by means of an external artificial pancreas.
Remission of diabetes was attempted in 12 recent acute onset ketosis-prone juvenile diabetes after short term (5 +/- 1 days) but excellent blood glucose control by the external artificial beta-cell. The comparison group comrised patients undergoing traditional treatment (n = 28). Nine (75%) persistent (over 3-14 months of duration) although partial (oral drugs required) remissions were obtained in the former group as compared to 3 (11%) in the latter group (p less than 0.05). Cases which showed remissions after insulin infusion had a plasma insulin response to IV glucagon still present before insulin infusion, and a daily urinary C-peptide excretion significantly enhanced after (p less than 0.01). Urinary C-peptide/blood glucose remained improved during the remission period. Thus, early effective treatment by means of the artificial pancreas may break the vicious circle hyperglycaemia-insulin depletion-hyperglycaemia and lead to frequent and sustained remissions of juvenile diabetes.
Acute Disease↗
[The influence of blood glucose on the filtrability of red cells in diabets. Variations after connection to an artificial pancreas (author's transl)].
In 36 treated diabetics (15 with insulin, 21 with oral hypoglycaemic agents) without any detectable arterial atheromatous lesion, there was a negative correlation between the filtrability of red cells and blood glucose levels (r = - 0.60) on the one hand and, secondly, glycosylated haemoglobin levels (r = - 0.40). In 17 insulindependents diabetics connected to an artificial pancreas, normalisation of blood glucose was accompanied by a concomitant increase in the filtrability of red cells, and improvement of spontaneous platelet agregation. Good control of diabetes would thus appear to be necessary to reduce the incidence of microangiopathy.
Artificial Organs↗
[Artificial pancreas: clinical and therapeutic value in 11 patients (author's transl)].
Fluctuations in blood glucose levels which occur in the brittle diabetic explain the difficulty of blood glucose control by insulin therapy as used at the present time. The artificial endocrine pancreas is a bedside device capable of maintaining blood sugar value within a normal range by the administration of adequate amounts of insulin or glucose given at the optimal time. The glycemic control of 11 brittle diabetics is improved during the 5 days after a 24 hour connection with the AEP. A better determination of adequate subcutaneous doses of insulin, based on the circadian insulin profile infused by the artificial endocrine pancreas, achieved the improvement of glycemia. Glucagon profile preceeding, during and after AEP is also discussed. Using a method of two injections daily of a mixture acterapid and semi-lente, as a general rule it is found that approximately fifty per cent of the dose must be given in the acterapid form. Glucagon value decreases during the 24 h artificial endocrine pancreas. This is suggestive of a possible role of hyperglucagonemia in brittle diabetes.
Adult↗
The hybrid artificial pancreas.
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Animals↗