Tensegrity and type 1 dermal dendrocytes in acromegaly.

BACKGROUND: Skin is enlarged and doughy in acromegaly. Alterations have been reported in the structure of the extracellular matrix (ECM) and in the mechanical properties of the dermis. It is recognized that internal tensions in the dermis give rise to active cell-ECM and cell-cell mechanical interactions. This mechanobiological aspect can lead to functional and conformational changes in the cells. Such alterations in connective tissue cells have not been explored so far in acromegaly. The aim of the study was to assess structural changes in the dermal ECM, and in the number and shape of factor XIIIa-positive type I dermal dendrocytes (DDs) in acromegaly. MATERIALS AND METHOD: A total of 32 patients with acromegaly (three untreated, 17 with active disease under somatostatin analogues and 12 cured) were examined. Both the maximum and the most recent IGF-1 (insulin-like growth factor) dosages recorded in the patients' files were retrieved. Skin biopsies were taken from their forearms. Histochemistry, immunohistochemistry, morphometry and electron microscopy were used. RESULTS: Collagen-bundle coarsening and acidic glycosaminoglycan deposits were found irrespective of the current endocrine status. Dermal dendrocytes were often markedly reduced in numbers, but those present were plump with few dendrites. A negative correlation was found between DD numbers and the maximum IGF-1 dosages recorded in the patients' files. A similar although weaker trend was found with the most recent IGF-1 dosages. CONCLUSIONS: Collagen, glycosaminoglycans and DDs appeared affected in acromegaly, even when the hormonal status was controlled after surgery and/or somatostatin analogue treatment. The persisting conformational change of DDs suggests a modification in cellular tensegrity, perhaps initiated by hormonal effects and probably maintained by alterations in the ECM interactions.