Vascular calcification; Stony bridge between kidney and heart

Autophagy reduces aortic calcification in diabetic mice by reducing matrix vesicle body-mediated IL-1β release

Vascular calcification (VC) is a common pathological process of cardiovascular disease that occurs in patients with type 2 diabetes mellitus (T2DM). However, the molecular basis of VC progression remains unknown. A GEO dataset (GSE146638) was analyzed to show that microbodies and IL-1β may play important roles in the pathophysiology of VC. The release of matrix vesicle bodies (MVBs) and IL-1β and the colocalization of IL-1β with MVBs or autophagosomes were studied by immunofluorescence in an in vivo diabetes mouse model with aortic calcification and an in vitro high glucose cell calcification model. MVB numbers, IL-1β levels and autophagy were increased in calcified mouse aortas and calcified vascular smooth muscle cells (VSMCs). IL-1β colocalized with MVBs and autophagosomes. The MVBs from calcified VSMCs induced the calcification of normal recipient VSMCs, and this effect was alleviated by silencing IL-1β. The autophagy inducer rapamycin reduced IL-1β expression and calcification in VSMCs, while these processes were induced by the autophagy inhibitor chloroquine. In conclusion, our results suggested that MVBs could carry IL-1β out of cells and induce VC in normal VSMCs, and these processes could be counteracted by autophagy. These results suggested that MVB-mediated IL-1β release may be an effective target for treating vascular calcification.

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.

[Bax inhibitor-1 inhibits calcification of vascular smooth muscle cells in vitro]

OBJECTIVE

To investigate the effect of Bax inhibitor-1(BI-1)on calcification of vascular smooth muscle cells(VSMCs).

METHODS

VSMCs were isolated from the thoracic aorta of SD rats.VSMCs or BI-1-overexpressing VSMCs(transfected with a BI-1-overexpressing plasmid) were cultured in normal medium or calcified medium containing β-glycerophosphate and calcium chloride, and the cell calcification was examined with Alizarin red staining.Enzyme-linked immunosorbent assay was used to determine the intracellular calcium content and alkaline phosphatase activity.The expression levels of Runt-related transcription factor 2 (RUNX2), bone morphogenetic protein 2 (BMP-2) and caspase-3 were detected with Western blotting.

RESULTS

After 14 days of culture in the calcified medium, the VSMCs showed significantly reduced expression of BI-1 protein(P=0.001).BI-1 overexpression in the VSMCs caused a significant reduction of calcium level and alkaline phosphatase activities(P=0.0006) and lowered the expression levels of RUNX2 and BMP-2 (P=0.0001) in the cells.The VSMCs with induced calcification exhibited a significantly increased apoptosis rate, but BI-1 overexpression obviously inhibited VSMC apoptosis in the calcified medium (P=0.0003).

CONCLUSION

BI-1 may attenuate vascular calcification by inhibiting calcium deposition, osteogenic differentiation and apoptosis.

Clinical Approach to Vascular Calcification in Patients With Non-dialysis Dependent Chronic Kidney Disease: Mineral-Bone Disorder-Related Aspects

Chronic kidney disease (CKD) is associated with a very high morbimortality, mainly from cardiovascular origin, and CKD is currently considered in the high- or very high risk- cardiovascular risk category. CKD-mineral and bone disorders (CKD-MBDs), including vascular and/or valvular calcifications, are also associated with these poor outcomes. Vascular calcification (VC) is very prevalent (both intimal and medial), even in non-dialysis dependent patients, with a greater severity and more rapid progression. Simple X-ray based-scores such as Adragão's (AS) are useful prognostic tools and AS (even AS based on hand-X-ray only) may be superior to the classic Kauppila's score when evaluating non-dialysis CKD patients. Thus, in this mini-review, we briefly review CKD-MBD-related aspects of VC and its complex pathophysiology including the vast array of contributors and inhibitors. Furthermore, although VC is a surrogate marker and is not yet considered a treatment target, we consider that the presence of VC may be relevant in guiding therapeutic interventions, unless all patients are treated with the mindset of reducing the incidence or progression of VC with the currently available armamentarium. Avoiding phosphate loading, restricting calcium-based phosphate binders and high doses of vitamin D, and avoiding normalizing (within the normal limits for the assay) parathyroid hormone levels seem logical approaches. The availability of new drugs and future studies, including patients in early stages of CKD, may lead to significant improvements not only in patient risk stratification but also in attenuating the accelerated progression of VC in CKD.