In vitro investigation of the principle of action of ammonium bituminosulfonate ointments on a 3D skin model.

Ammonium bituminosulfonate preparations have been used for various dermatological diseases since the 19th century. The dark preparation is known as the so-called "drawing salve" (Ichtholan®) for the treatment of abscesses and furuncles. The underlying activity is in part the loosening of the skin, which facilitates pus extraction and treatment of deep inflammations. For this investigation 3D skin models were incubated with ointments containing different ammonium bituminosulfonate concentrations. Histological and immunohistochemical staining as well as penetration investigation were carried out. The effect of dark ammonium bituminosulfonate ointments on skin loosening was investigated to reveal the underlying mechanism. The skin loosening effect could be proved by HE-staining for ammonium bituminosulfonate treated skin models. This effect was concentration dependent. While treatment with ammonium bituminosulfonate ointment had no influence on keratin expression, high concentrated ointments led to decreased filaggrin and laminin expression. Treatment of skin models with ABS ointments led to an increased skin permeability, which was concentration dependent. For the first time the skin loosening effect of ammonium bituminosulfonate ointment has been demonstrated on 3D skin models. This effect is at least in part caused by the interaction of the substance with structure dependent proteins of the epidermis.

Sodium Bituminosulfonate Used to Treat Rosacea Modulates Generation of Inflammatory Mediators by Primary Human Neutrophils.

BACKGROUND: Sodium bituminosulfonate is derived from naturally occurring sulphur-rich oil shale and is used for the treatment of the inflammatory skin disease rosacea. Major molecular players in the development of rosacea include the release of enzymes that process antimicrobial peptides which, together with reactive oxygen species (ROS) and vascular endothelial growth factor (VEGF), promote pro-inflammatory processes and angiogenesis. The aim of this study was to address the molecular mechanism(s) underlying the therapeutic benefit of the formulation sodium bituminosulfonate dry substance (SBDS), which is indicated for the treatment of skin inflammation, including rosacea. METHODS: We investigated whether SBDS regulates the expression of cytokines, the release of the antimicrobial peptide LL-37, calcium mobilization, proteases (matrix metalloproteinase, elastase, kallikrein (KLK)5), VEGF or ROS in primary human neutrophils. In addition, activity assays with 5-lipoxygenase (5-LO) and recombinant human MMP9 and KLK5 were performed. RESULTS: We observed that SBDS reduces the release of the antimicrobial peptide LL-37, calcium, elastase, ROS and VEGF from neutrophils. Moreover, KLK5, the enzyme that converts cathelicidin to LL-37, and 5-LO that produces leukotriene (LT)A4, the precursor of LTB4, were both inhibited by SBDS with an IC50 of 7.6 µg/mL and 33 µg/mL, respectively. CONCLUSION: Since LTB4 induces LL-37 which, in turn, promotes increased intracellular calcium levels and thereby, ROS/VEGF/elastase release, SBDS possibly regulates the LTB4/LL-37/calcium - ROS/VEGF/elastase axis by inhibiting 5-LO and KLK5. Additional direct effects on other pro-inflammatory pathways such as ROS generation cannot be ruled out. In summary, SBDS reduces the generation of inflammatory mediators from human neutrophils possibly accounting for its anti-inflammatory effects in rosacea.