Aortic Vascular Calcification: Cholesterol Lowering Does Not Reduce Progression in Patients With Familial Hypercholesterolemia—or Does It?

Ligustrazine activate the PPAR-γ pathway and play a protective role in vascular calcification

OBJECTIVE

The purpose of this study was to explore the role of ligustrazine in vascular calcification.

METHODS

After β-GP stimulation, vascular smooth muscle cells (VSMCs) were detected by Alizarin Red Staing staining. Calcium content and alkaline phosphatase (ALP) activity were detected by intracellular calcium assay kit and ALP assay kit, respectively. The expression of peroxisome proliferation-activated receptor (PPAR-γ) pathway-related proteins was detected by Western blot. PPAR-γ, MSX2, osteopontin (OPN), sclerostin, and BGP were detected by RT-PCR.

RESULTS

β-GP induced the decreased activity and expression of PPAR-γ and ALP in VSMCs, while ligustrazine activated the expression of PPAR-γ. Through activation of PPAR-γ, ligustrazine decreased β-GP-induced VSMC calcification, decreased the expression of markers of osteogenesis and chondrogenic differentiation, and increased the expression of VSMC markers.

CONCLUSION

Ligustrazine activates the PPAR-γ pathway and plays a protective role in vascular calcification.

The Emerging Role of Mesenchymal Stem Cells in Vascular Calcification

Vascular calcification (VC), characterized by hydroxyapatite crystal depositing in the vessel wall, is a common pathological condition shared by many chronic diseases and an independent risk factor for cardiovascular events. Recently, VC is regarded as an active, dynamic cell-mediated process, during which calcifying cell transition is critical. Mesenchymal stem cells (MSCs), with a multidirectional differentiation ability and great potential for clinical application, play a duplex role in the VC process. MSCs facilitate VC mainly through osteogenic transformation and apoptosis. Meanwhile, several studies have reported the protective role of MSCs. Anti-inflammation, blockade of the BMP2 signal, downregulation of the Wnt signal, and antiapoptosis through paracrine signaling are possible mechanisms. This review displays the evidence both on the facilitating role and on the protective role of MSCs, then discusses the key factors determining this divergence.

Inflammatory and metabolic mechanisms underlying the calcific aortic valve disease

Although calcific aortic stenosis is a very common disease with major adverse cardiovascular events and healthcare costs, there are no effective medical interventions to delay or halt its progression. Cardiometabolic risk factors, including smoking and male sex, are linked to aortic stenosis. Emerging studies have identified important regulatory roles for immunological and inflammatory responses, including oxidized lipids, various cytokines, and biomineralization. Recent clinical and experimental studies in atherosclerosis and osteoporosis have demonstrated that oxidative stress and oxidized lipids decrease bone formation in the skeletal system while they increase bone formation in the cardiovascular system. Multidisciplinary factors contribute to vascular calcification, including inflammation and metabolic regulation of osteogenesis in the cardiovascular system via similar signaling pathways as bone formation. Calcific aortic valve disease (CAVD) is no longer considered a simple passive process of calcium deposition that occurs with advanced age. Biomineralization in CAVD is a complex, regulated process that involves valvular, circulating, bone marrow-derived cells, macrophage heterogeneity and genetic factors along with biochemical and mechanical factors. The current review will discuss the recently discovered important role of inflammation, metabolic risk factors, and molecular and cellular mechanisms that promote CAVD, as well as the link between osteogenic signals in the skeletal and cardiovascular systems. This may inform future therapeutic strategies for CAVD progression.