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- Parikka, V, et al.
(författare)
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Estrogen responsiveness of bone formation in vitro and altered bone phenotype in aged estrogen receptor-alpha-deficient male and female mice
- 2005
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Ingår i: European Journal of Endocrinology. - : Oxford University Press (OUP). - 1479-683X .- 0804-4643. ; 152:2, s. 301-314
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Although the beneficial effects of estrogen on bone are well known, the roles of estrogen receptors (ERs) in mediating these effects are not fully understood. Methods: To study the effects of long-term ERalpha deficiency, bone phenotype was studied in aged ERalpha knockout (ERKO) mice. In addition, ERKO osteoclasts and osteoblasts were cultured in vitro. Design and results: Histomorphometric analysis showed that the trabecular bone volume and thickness were significantly increased and the rate of bone formation enhanced in both male and female ERKO mice in comparison to the witd-type animals. In ERKO males, however, the bones were thinner and their maximal bending strengths decreased. Consistent with previous reports, the bones of knockout mice, especially of female mice, were shorter than those of wild-type mice. In addition, the growth plates were totally absent in the tibiae of aged ERKO females, whereas the growth plate cartilages were detectable in wild-type females as well as in all the males. Analysis of cultured bone marrow cells from 10- to 12-week-old mice demonstrated that 17beta-estradiol could stimulate osteoblastic differentiation of bone marrow cells derived from ERKO mice relatively to the same extent as those derived from wild-type mice. This was demonstrated by increases in synthesis of type I collagen, activity of alkaline phosphatase and accumulation of calcium in cultures. Total protein content was, however, reduced in ERKO osteoblast cultures. Conclusions: These results show altered bone phenotype in ERKO mice and demonstrate the stimulatory effect of estrogen on ostcoblasts even in the absence of full-length ERalpha.
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- Yazdanparast, P., et al.
(författare)
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Action of topical thyroid hormone analogue, triiodothyroacetic acid in reversing glucocorticoid-induced skin atrophy in humans
- 2006
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Ingår i: Thyroid. ; 15:11, s. 1157-62
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Tidskriftsartikel (refereegranskat)abstract
- The present study concerns the effect of topical treatment with a cream formulation of triiodothyroacetic acid (TRIAC) in comparison with a placebo preparation in producing a reversal of skin atrophy induced by long-term employment of topical glucocorticoid therapy in humans. A total of 39 patients with clinically verified skin atrophy due to long-term use of topical potent glucocorticoids were randomized. The changes in skin thickness, elastic fibers, and hyaluronic acid were evaluated by means of sonography and histology. After 8 weeks' treatment, the skin thickness measured by sonography increased by 16% in the epidermis, 8% in the dermis, and epidermis + dermis in the placebo group. In the TRIAC 0.1% group, the corresponding values were 24% ( p=0.063) in the epidermis, 28% ( p=0.042) in the dermis, and 25% ( p=0.039) in the epidermis + dermis. After 8 weeks, in the placebo group, the skin thickness measured by biopsy increased by 5% in the epidermis, epidermis + dermis, and 6% in the dermis. In the TRIAC 0.1% group, the corresponding values were 31% ( p=0.041) in the epidermis, 46% ( p=0.041) in the dermis and 44% ( p=0.043) in the epidermis + dermis. After 8 weeks, the elastic fibers of moderately irregular and thickened fibers increased by 56% in the placebo group and 100% ( p=0.043) in the TRIAC 0.1 group. This study indicates that topical treatment with TRIAC appears to reverse glucocorticoid-induced skin atrophy under the narrow conditions tested.
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