Graves' disease-associated changes in the serum lysosomal glycosidases activity and the glycosaminoglycan content.
BACKGROUND
This study was undertaken to elucidate the influence of Graves' hyperthyroidism upon the metabolism of proteoglycans (PGs), the extracellular matrix (ECM) components. We determined the serum activity of lysosomal hydrolases contributing to GAGs degradation (N-acetyl-beta-D-glucosaminidase, beta-D-glucuronidase, beta-D-galactosidase, alpha-D-mannosidase, beta-D-xylosidase and alpha-L-fucosidase). An effect of Graves' hyperthyroidism on total serum GAGs content was also analysed.


METHODS
Blood samples were taken from 30 patients with newly diagnosed Graves' disease, prior to antithyroid treatment and after attainment of euthyroid state, as well as from 30 healthy individuals.


RESULTS
The activity of all investigated enzymes involved in GAGs degradation was found markedly increased in blood serum of patients with hyperthyroidism, except for alpha-D-mannosidase, which was not significantly modified. Antithyroid treatment with thiamazole resulted in normalization of the lysosomal glycosidases activity, so they no longer differed from the healthy subjects. The total glycosaminoglycans content in blood serum of patients with newly diagnosed untreated Graves' disease significantly increased compared to control group. Following thiamazole therapy total serum amount of GAGs decreased significantly, but was still markedly increased as compared to serum of healthy individuals.


CONCLUSIONS
The obtained results indicate that Graves' hyperthyroidism is associated with extracellular matrix components' alterations. Furthermore, we suggest that general increase of the serum lysosomal glycosidases activity and serum GAG concentration may both result from the same reason, i.e. excessive reactive oxygen species formation in the course of hyperthyroidism due to Graves' disease.
Komosińska-Vassev
Katarzyna
K
Department of Clinical Chemistry and Laboratory Diagnostics, Medical University of Silesia, ul. Jagiellonska 4, 41-200, Sosnowiec, Poland. kvassev@farmant.slam.katowice.pl
Olczyk
Krystyna
K
Koźma
Ewa M
EM
Winsz-Szczotka
Katarzyna
K
Olczyk
Paweł
P
Wisowski
Grzegorz
G
D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D006025:Glycosaminoglycans / Q000097:blood* / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000097:blood*; D006111:Graves Disease / Q000097:blood* / Q000201:enzymology*; D006801:Humans; D008247:Lysosomes / Q000201:enzymology*; D008297:Male; D013960:Thyroid Function Tests
D006025:Glycosaminoglycans; D006026:Glycoside Hydrolases