The possible protective effect of simvastatin and pioglitazone separately and in combination on bleomycin-induced changes in mice thin skin

Anti-fibrotic effects of statin drugs: a review of evidence and mechanisms

Fibrosis is a pathological repair process common among organs, that responds to damage by replacement of tissue with non-functional connective tissue. Despite the widespread prevalence of tissue fibrosis, manifesting in numerous disease states across myriad organs, therapeutic modalities to prevent or alleviate fibrosis are severely lacking in quantity and efficacy. Alongside development of new drugs, repurposing of existing drugs may be a complementary strategy to elect anti-fibrotic compounds for pharmacologic treatment of tissue fibrosis. Drug repurposing can provide key advantages to de novo drug discovery, harnessing the benefits of previously elucidated mechanisms of action and already existing pharmacokinetic profiles. One class of drugs a wealth of clinical data and extensively studied safety profiles is the statins, a class of antilipidemic drugs widely prescribed for hypercholesterolemia. In addition to these widely utilized lipid-lowering effects, increasing data from cellular, pre-clinical mammalian, and clinical human studies have also demonstrated that statins are able to alleviate tissue fibrosis originating from a variety of pathological insults via lesser-studied, pleiotropic effects of these drugs. Here we review literature demonstrating evidence for direct effects of statins antagonistic to fibrosis, as well as much of the available mechanistic data underlying these effects. A more complete understanding of the anti-fibrotic effects of statins may enable a clearer picture of their anti-fibrotic potential for various clinical indications. Additionally, more lucid comprehension of the mechanisms by which statins exert anti-fibrotic effects may aid in development of novel therapeutic agents that target similar pathways but with greater specificity or efficacy.

Radioprotective Effect of Pioglitazone Against Genotoxicity Induced by Ionizing Radiation in Healthy Human Lymphocytes

OBJECTIVE

Pioglitazone (PG) is used to control high blood sugar in patients with type 2 diabetes mellitus. PG acts as a peroxisome proliferator-activated receptor γ agonist. In addition to the insulin-sensitizing effect, PG possesses anti-inflammatory effect. In this study, the protective effect of PG was evaluated against DNA damage induced by ionizing radiation in healthy human lymphocytes.

METHODS

The microtubes containing human whole blood were treated with PG at various concentrations (1-50 μM) for three hours. Then, the blood samples were irradiated with X-ray. Lymphocytes were cultured for determining the frequency of micronuclei as a genotoxicity biomarker in binucleated lymphocytes.

RESULTS

The mean percentage of micronuclei was significantly increased in human lymphocytes when exposed to IR, while it was decreased in lymphocytes pre-treated with PG. The maximum reduction in the frequency of micronuclei in irradiated lymphocytes was observed at 5 μM of PG treatment (48% decrease).

CONCLUSION

The anti-inflammatory property suggested the mechanism action of PG for protecting human lymphocytes against genotoxicity induced by ionizing radiation.

Human Skin Permeation Studies with PPARγ Agonist to Improve Its Permeability and Efficacy in Inflammatory Processes

Rosacea is the most common inflammatory skin disease. It is characterized by erythema, inflammatory papules and pustules, visible blood vessels, and telangiectasia. The current treatment has limitations and unsatisfactory results. Pioglitazone (PGZ) is an agonist of peroxisome proliferator-activated receptors (PPARs), a nuclear receptor that regulates important cellular functions, including inflammatory responses. The purpose of this study was to evaluate the permeation of PGZ with a selection of penetration enhancers and to analyze its effectiveness for treating rosacea. The high-performance liquid chromatography (HPLC) method was validated for the quantitative determination of PGZ. Ex vivo permeation experiments were realized in Franz diffusion cells using human skin, in which PGZ with different penetration enhancers were assayed. The results showed that the limonene was the most effective penetration enhancer that promotes the permeation of PGZ through the skin. The cytotoxicity studies and the Draize test detected cell viability and the absence of skin irritation, respectively. The determination of the skin color using a skin colorimetric probe and the results of histopathological studies confirmed the ability of PGZ-limonene to reduce erythema and vasodilation. This study suggests new pharmacological indications of PGZ and its possible application in the treatment of skin diseases, namely rosacea.