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
Communication
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.
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.
COOPERATION - INSTITUTIONS
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 Other information about the project.