Attenuation of Chondrogenic Transformation in Vascular Smooth Muscle by Dietary Quercetin in the MGP-Deficient Mouse Model

RATIONALE: Cartilaginous metaplasia of vascular smooth muscle (VSM) is characteristic for arterial calcification in diabetes and uremia and in the background of genetic alterations in matrix Gla protein (MGP). A better understanding of the molecular details of this process is critical for the development of novel therapeutic approaches to VSM transformation and arterial calcification. OBJECTIVE: This study aimed to identify the effects of bioflavonoid quercetin on chondrogenic transformation and calcification of VSM in the MGP-null mouse model and upon TGF-β3 stimulation in vitro, and to characterize the associated alterations in cell signaling. METHODS AND RESULTS: Molecular analysis revealed activation of β-catenin signaling in cartilaginous metaplasia in Mgp-/- aortae in vivo and during chondrogenic transformation of VSMCs in vitro. Quercetin intercepted chondrogenic transformation of VSM and blocked activation of β-catenin both in vivo and in vitro. Although dietary quercetin drastically attenuated calcifying cartilaginous metaplasia in Mgp-/- animals, approximately one-half of total vascular calcium mineral remained as depositions along elastic lamellae. CONCLUSION: Quercetin is potent in preventing VSM chondrogenic transformation caused by diverse stimuli. Combined with the demonstrated efficiency of dietary quercetin in preventing ectopic chondrogenesis in the MGP-null vasculature, these findings indicate a potentially broad therapeutic applicability of this safe for human consumption bioflavonoid in the therapy of cardiovascular conditions linked to cartilaginous metaplasia of VSM. Elastocalcinosis is a major component of MGP-null vascular disease and is controlled by a mechanism different from chondrogenic transformation of VSM and not sensitive to quercetin

Ectopic calcification in diabetic vascular disease.

INTRODUCTION: Cardiovascular diseases represent over one-half of all deaths in both type 1 and type 2 diabetes mellitus. In diabetic patients, vascular calcifications are more frequently observed than in people without diabetes. In particular, elevated degrees of coronary artery and valvular calcifications are reported in populations with diabetes. AREAS COVERED: We will present and discuss findings from clinical and basic science studies that investigate the pathophysiological processes leading to exaggerated arterial/valve calcification in diabetic patients. We will also illustrate the likely effects of the current therapies on vascular calcification progression in diabetic patients. A special focus will be dedicated to the contribution of resident/circulating calcifying cells to the calcific processes observed under diabetic conditions. EXPERT OPINION: Interest in the topic of ectopic calcification in diabetic vascular disease is expanding and more knowledge is adding on its mechanisms and consequences. Importantly, new therapeutic targets are emerging, implying possible future chances to modulate vascular calcification for cardiovascular protection