SVIBOR - Project code: 3-01-151


Strossmayerov trg 4, HR - 10000 ZAGREB
tel.: +385 1 459 44 44, fax: +385 1 459 44 69


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Project code: 3-01-151


Main researcher: LIPOVAC, VASKRESENIJA (25994)

Type of research: basic
Duration from: 04/30/91. to 12/31/95.

Papers on project (total): 18
Papers on project quoted in Current Contents: 11
Institution name: Institut za dijabetes, endokrinologiju i bolesti metabolizma "Vuk Vrhovac", Zagreb (45)
Department/Institute: Department of laboratory medicine
Address: Dugi dol 4 a
City: 10000 - Zagreb, Croatia
Phone: 385 (0)1-2332-222
Fax: 385 (0)1-2331-515
Phone: 385 (0)

Summary: A significant decrease of sialic acid concentration was found in islet of Langerhans from alloxan diabetic rats. This change correlates with duration of diabetes, age of animals, and islet size. The optimal experimental condition for islet isolation, cell culturing and encapsulation in HEMA-MMA medium have been determined. Correlation between sialic acid content and insulin release in vitro from encapsulated islet have been found. The obtained results are consistent with hypothesis of the possible role for sialic acid in insulin release from the beta cells of islet of Langerhans. The possible role of sialic acid in determining the rheological properties of blood cells have been examined by two aspects. a) Exogenous gangliosides (sialic-acid-containing glycosphingolipids) do not excert any rheological effect in vitro on eryhtrocytes isolated from blood of healthy subjects. In contrast to this gangliosides protect significantly the erythrocyte filterability loss induced by Ca2+ ionophore A23187 treatment. We have demonstrated a simmilar effect of gangliosides in vitro, on isolated on polymorphonuclear leucocytes in insulin dependent diabetic patients with chronic renal failure. b) Amelioration of erythrocyte filterability after insulin injection was observed only in IDDM patients with good and fair regulation, but not in those with poor control. After erythropoietin therapy an improvement of erythrocyte filterability, but without complete normalization has been observed in insulin dependent diabetic patients with anemia due to chronic renal insuficiency. The results show the reversibility of rheological impairments by the acute action of some agenses, which is of importance for further examinations of this research problem. Of special interest are our observations of capability of sialic acid to inhibit albumin glycation-induced flourescence. The overall results of our investigation had provided new evidences which support the important role of sialic acid in the pathogenesis of experimental diabetes as well as in the hemoreologic abnormalities in human diabetes which may contribute to the development of diabetic complications.

Keywords: Sialic acid, islet of Langerhans, alloxan diabetes, insulin release, erythrocyte filterability, rheology, gangliosides, insulin dependent diabetes.

Research goals: The main goal of this study is to establish the possible role of sialic acid in the changes of some cells properties and functions found in diabetes and its complications. Specific aims: a) To establish the role of sialic acid in insulin secretion from the islets of Langerhans from control and alloxan diabetic rats. b) To establish the role of sialic acid in rheological properties of blood cells. c) To examine the effect of sialic acid on non-enzymatic glycosylation of protein. The results of this study will provide evidences for better understanding of the possible role of sialic acid in the pathogenesis of diabetes and its complications, as well as to the development of methods and techniques of diabetes therapy and early detection of diabetic complications.


  1. Name of institution: INSTITUT "RUĐER BOŠKOVIĆ", Odjel za eksperimentalnu biologiju i medicinu
    Type of institution: University/Faculty
    Type of cooperation: Joint publishing of scientific papers
    City: 10000 - Zagreb, Croatia

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Last update: 10/02/95