ABSTRACT
INTRODUCTION: Calcium hydroxylapatite microspheres suspended in a gel carrier of sodium carboxymethylcellulose (CaHA; Radiesse®) has demonstrated safe and effective restoration of facial volume in clinical trials, as well as collagen biostimulation leading to skin quality improvement. The potential with CaHA, as with any filler, to produce overcorrection and subsequent complications has led to the search for a reversal agent. Sodium thiosulfate (STS) was proposed based on experience with it as a chelating agent to treat calciphylaxis. Previous pilot studies with small sample sizes have suggested its efficacy in the reduction of CaHA volume and nodule formation. The present study focuses on the verification of this effect using various readout methods in preclinical experiments. METHODS: We use both in vitro (co-incubation of STS with CaHA) and in vivo (injections in farm pig) methods with readout techniques such as 3D camera analysis, micro-computed tomography ex vivo (µCT), computed tomography in vivo (CT), histopathology and scanning electron microscopy. RESULTS: We did not obtain any indications of CaHA degradation by STS, either in vitro or in vivo. 3D-camera analysis also did not show any decreasing effect of STS on CaHA. However, histology, µCT ex vivo, and CT in vivo indicated a decrease of Radiesse amount/volume after STS treatment, which could be attributed to dispersion effect. It should be noted that necrosis and haemorrhages were observed after STS treatment. DISCUSSION: Results suggest no indication of CaHA microspheres degradation with STS and that the STS mechanism of action on CaHA is consistent with a dispersion effect. Observed necrosis is a further obstacle in the use of STS.
ABSTRACT
Since the last decade, nanodispersed drug delivery systems gain increasingly more importance for therapeutic research fields. The forced transport to the centers of inflammation is supposed to take advantage as a novel strategic approach. Thus, the focus of this study was to investigate the applicability of ubiquinone nanoformulations against oxidative stress. The physiological reduction of reactive oxygen species (ROS) seems to be a promising treatment to point out the potential effects of these sophisticated nano-constructs. Therefore, the yeast strain Saccharomyces cerevisiae N34 was used for in vitro studies as a representative for eukaryotic organisms. Growth parameters during sequential fed batch-cultivation were monitored online using focused beam reflectance measurement (FBRM) method. The ability to control diverse cellular processes makes this yeast strain to a valuable tool for the initial investigation by understanding the fundamental mechanisms of nanoparticulate formulations onto eukaryotic cells. Furthermore, the characteristic stress response of yeast cell culture was examined, so that drug effects could be determined quantitatively. As a chemical stressor, diamide was tested in the range of 1-1000 mg diamide per g cell dry weight (CDW). The ubiquinone nanoformulation demonstrated a total stress reduction of approximately 14% in the yeast culture, confirming the potential applicability of ubiquinone.
