This page shows all publications that appeared in the IASI annual research reports. Authors currently affiliated with the Institute are always listed with the full name.

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Show all publications of the year  2011, with author Palumbo P., in the category IASI Research Reports (or show them all):

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IASI Research Report n. 11-09  (Next)  

Pasquale Palumbo, Ditlevsen S., Bertuzzi A., De Gaetano A.

MATHEMATICAL MODELING OF THE GLUCOSE-INSULIN SYSTEM: A REVIEW PAPER

ABSTRACT

The glucose-insulin system oers one of the clearest and simplest examples of homeostatic control in the organism. The level of glucose in blood needs to be kept within a narrow range. Since it represents the main metabolic substrate, or energy source, for brain tissue, abnormally low glucose concentrations give rise to anxiety, tremors, aggressiveness, obfuscation, coma and eventually death. On the other hand, excessive plasma glucose concentrations produce microvascular damages (notably in the retina and kidney) and neural damages, leading among others to blindness and chronic renal insuciency. The way the body controls glycemia seems deceptively simple. Essentially a single hormone (insulin) is secreted by the -cells of the pancreas in response to rising glucose concentrations (hyperglycemia). Insulin eects include increasing peripheral tissue glucose uptake (mainly by the muscle and fat tissues) and decreasing spontaneous glucose output by the liver. When insulin secretion by the pancreas is insucient or absent, the clinical picture of Type 1 Diabetes Mellitus (T1DM) results; when insulin is secreted in normal, or supranormal amounts, but it is ineective in lowering glycemia to normal levels, Type 2 Diabetes Mellitus (T2DM) is said to be present. A number of hormones contribute to rescuing the organism from hypoglycemia (adrenalin, glucagon, growth hormone, cortisol): however, since in clinical practice the situation of interest is normally inappropriately high glycemia, concentrating attention on the response to hyperglycemia by insulin seems justied, at least as a rst modeling approach. We may therefore consider, as a rst approximation, a simplied system in which a single metabolite (glucose) is controlled by a single hormone (insulin). This system will have to maintain glycemia in the absence of food intake, and will have to suppress hyperglycemia rapidly after meals, without incurring in dangerous hypoglycemias. We see therefore that the glucose-insulin system could be viewed, at least approximately, as a feedback control with a controller (the pancreas) and multiple eectors (muscle, liver, fat tissue), but where the only state variables of interest are glycemia and insulinemia. The present review has the goal of situating the biomedical problem of the glucose-insulin homeostasis from a physiological and clinical viewpoint, then describing the main combined experimental-modeling tools which are currently employed in investigating the behavior of the control system in individuals or populations.