In Vitro Effects of PTH (1-84) on Human Skeletal Muscle-Derived Satellite Cells

Parathyroid hormone (PTH) is a hormone secreted by the parathyroid glands. Despite its well-known characterized anabolic and catabolic actions on the skeleton, the in vitro effects of PTH on skeletal muscle cells are limited and generally performed on animal models. The aim of this study was to evaluate the effects of a short impulse of PTH (1-84) on the proliferation and the differentiation of skeletal muscle satellite cells isolated from human biopsies. The cells were exposed for 30 min to different concentrations of PTH (1-84), from 10−6 mol/L to 10−12 mol/L. ELISA was used to assay cAMP and the myosin heavy-chain (MHC) protein. The proliferation was assayed by BrdU and the differentiation by RealTime-qPCR. A statistical analysis was performed by ANOVA followed by Bonferroni’s test. No significant variations in cAMP and the proliferation were detected in the isolated cells treated with PTH. On the other hand, 10−7 mol/L PTH on differentiated myotubes has shown significant increases in cAMP (p ≤ 0.05), in the expression of myogenic differentiation genes (p ≤ 0.001), and in the MHC protein (p ≤ 0.01) vs. untreated controls. This work demonstrates for the first time the in vitro effects of PTH (1-84) on human skeletal muscle cells and it opens new fields of investigation in muscle pathophysiology

Study of the Expression and Function of Calcium-Sensing Receptor in Human Skeletal Muscle

Skeletal muscle has an outstanding capacity for regeneration in response to injuries, but there are disorders in which this process is seriously impaired, such as sarcopenia. Pharmacological treatments to restore muscle trophism are not available, therefore, the identification of suitable therapeutic targets that could be useful for the treatment of skeletal reduced myogenesis is highly desirable. In this in vitro study, we explored the expression and function of the calcium-sensing receptor (CaSR) in human skeletal muscle tissues and their derived satellite cells. The results obtained from analyses with various techniques of gene and protein CaSR expression and of its secondary messengers in response to calcium (Ca2+) and CaSR drugs have demonstrated that this receptor is not present in human skeletal muscle tissues, neither in the established satellite cells, nor during in vitro myogenic differentiation. Taken together, our data suggest that, although CaSR is a very important drug target in physiology and pathology, this receptor probably does not have any physiological role in skeletal muscle in normal conditions

Reverse Expansion for Breast Reconstruction after Skin-sparing and Nipple-sparing Mastectomy: Our First 100 Cases

Background:. Patients with breast cancer have experienced advancements both in oncological treatment and in aesthetics as a result of developments in reconstructive techniques. We aimed to present our experience with the reverse expansion technique, summarizing the results of our first 100 cases of reconstruction after skin-sparing mastectomy and nipple-sparing mastectomy. Methods:. From January 2010 to September 2018, 253 breast reconstruction procedures were performed on 100 patients. The reverse expansion technique consists of autologous fat tissue transplantation requiring the combined use of a skin expander and of multiple lipofilling sessions. At the beginning of every session the breast expander was deflated by removing a saline volume similar to that of the fat to be injected. Results:. Overall, 56 breast reconstructions after skin-sparing mastectomy and 44 after nipple-sparing mastectomy were performed. An average of 661.5 cm3 of fat per session was harvested and an average of 305.3 cm3 per breast was injected. The average number of sessions to achieve breast reconstruction was 2.53. Only four complications after 253 procedures (1.5%) were reported: one donor site hemorrhage due to genetic lack of coagulation factors, and three surgical site infections. Conclusions:. Considering the large number of positive factors such as a fast postoperative recovery, an easy learning curve, a lack of need of a specialized surgical team, a natural look of the breast shape, and the soft consistency of the grafted tissue, we believe this technique could be the first choice for autologous reconstruction after skin-sparing mastectomy and nipple-sparing mastectomy

Synthetic cannabinoid ajulemic acid exerts potent antifibrotic effects in experimental models of systemic sclerosis

Background: Cannabinoids modulate fibrogenesis in scleroderma. Ajulemic acid (AjA) is a non-psychoactive synthetic analogue of tetrahydrocannabinol that can bind the peroxisome proliferator-activated receptor-γ (PPAR-γ). Recent evidence suggests a key role for PPAR-γ in fibrogenesis. Objective: To determine whether AjA can modulate fibrogenesis in murine models of scleroderma. Material and methods: Bleomycin-induced experimental fibrosis was used to assess the antifibrotic effects of AjA in vivo. In addition, the efficacy of AjA in pre-established fibrosis was analysed in a modified model of bleomycin-induced dermal fibrosis and in mice overexpressing a constitutively active transforming growth factor β (TGFβ) receptor I. Skin fibrosis was evaluated by quantification of skin thickness and hydroxyproline content. As a marker of fibroblast activation, α-smooth muscle actin was examined. To study the direct effect of AjA in collagen neosynthesis, skin fibroblasts from patients with scleroderma were treated with increasing concentrations of AjA. Protein expression of PPAR-γ, and its endogenous ligand 15d-PGJ2, and TGFβ were assessed before and after AjA treatment. Results: AjA significantly prevented experimental bleomycin-induced dermal fibrosis and modestly reduced its progression when started 3 weeks into the disease. AjA strongly reduced collagen neosynthesis by scleroderma fibroblasts in vitro, an action which was reversed completely by co-treatment with a selective PPAR-γ antagonist. Conclusions: AjA prevents progression of fibrosis in vivo and inhibits fibrogenesis in vitro by stimulating PPAR-γ signalling. Since therapeutic doses of AjA are well tolerated in humans, it is suggested that AjA as an interesting molecule targeting fibrosis in patients with scleroderma