Ghrelin and obestatin in thyroid gland — immunohistochemical expression in nodular goiter, papillary and medullary cancer

Abstract

Introduction. Previous studies analyzing ghrelin and obestatin expression in thyroid gland tissue are not unanimous and are mostly related to ghrelin. The role of ghrelin and obestatin in the thyroid gland appears very interesting due to their probable involvement in cell proliferation. Furthermore, since the thyroid gland is associated with the maintenance of energy balance, the relationship between ghrelin, obestatin and thyroid function is worthy of consideration. The aim of the study was to assess ghrelin and obestatin immunocytochemical expression in nodular goiter (NG), papillary cancer (PTC) and medullary cancer (MTC). Material and methods. Analyzed samples included 9 cases of NG, 8 cases of PTC and 11 cases of MTC. The analysis of ghrelin and obestatin expression was performed by use of the immunohistochemical (IHC) EnVision system and evaluated with filter HSV software (quantitative morphometric analysis). Results. Quantitative ghrelin expression in MTC cells was higher than in NG (p = 0.013) and correlated negatively with the size of the tumor (r= -0.829, p < 0.05). We did not observe any differences in ghrelin expression neither between MTC and PTC nor between NG and PTC. Obestatin immunoexpression pattern in all analyzed specimens was irregular and poorly accented. The strongest immunoreactivity for obestatin was demonstrated in NG. In MTC obestatin expression was significantly weaker than in NG and PTC (p < 0.05 in both cases). In NG the intensity of obestatin immunostaining was significantly higher than that of ghrelin (p = 0.03). Conversely, ghrelin expression in MTC was definitely more evident than obestatin immunoreactivity (p < 0.01). There was no statistically significant difference between ghrelin and obestatin expression in PTC. No correlations were detected between reciprocal tissue expressions of ghrelin and obestatin in the analyzed specimens of NG, PTC or MTC. Conclusions. The differences between ghrelin expression in NG and MTC suggest that ghrelin may be involved in thyroid cell proliferation. The differences between ghrelin and obestatin immunoreactivity in benign and malignant thyroid tumors could support the theory of alternative transcription of the preproghrelin gene and independent production of ghrelin and obestatin.

The association between irisin and muscle metabolism in different thyroid disorders

“…According to the obtained data, it may be assumed that FNDC5 gene expression in thyroid tissue is not associated with the development of thyroid malignancy. Such overexpression has been reported for several anti‐apoptotic proteins, such as nicotinamide phosphoribosyltransferase gene ( NAMPT ), ghrelin or BIRC5 encoding surviving …”

Expression of cytokeratin-19 (CK19) in the classical subtype of papillary thyroid carcinoma: the experience of one center in the Silesian region

“…CSTPTCs may also be very aggressive, as demonstrated by the recurrence of the disease. Environmental, genetic, immunological, and hormonal factors are considered possible pathomechanisms for thyroid malignancy recurrence [10,11].…”

Ghrelin-immunoreactive cells in the gastrointestinal tract of hypertensive rats

“…Moreover, experimental and clinical studies demonstrated that ghrelin decreased blood pressure in healthy individuals and animals with normal blood pressure as well as animals with hypertension [13]. It was suggested that the mechanisms responsible for the hypotensive effects of ghrelin include the suppression of sympathetic activity or direct vasodilatory activities [5,14].…”

“…The mucosa in other parts of the stomach and intestines contains distinctly lower ghrelin concentrations with the lowest being observed in the colon [3]. Another area participating in ghrelin synthesis is the central nervous system with the neurons of the arcuate nucleus in the hypothalamus being the most active [4] as well as thyroid gland [5].…”