T3 inhibits the calcification of vascular smooth muscle cells and the potential mechanism

[helvella]

Yet more evidence of the importance of T3...

Am J Transl Res. 2016; 8(11): 4694–4704.

Published online 2016 Nov 15.

PMCID: PMC5126314

T3 inhibits the calcification of vascular smooth muscle cells and the potential mechanism

Xiaodan Chang,1,2,* Baohong Zhang,3,* Li Lihua,4 and Zhichun Feng1

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Abstract

Objective: This study aimed to investigate the potential molecular mechanism underlying the T3 induced vascular calcification and phenotype transformation of vascular smooth muscle cells (VSMCs). Methods: Rat thoracic aortic smooth muscle cells (A7r5) were cultured in vitro and randomly assigned into normal control group, calcification group, T3 group and inhibitor group. Results: When compared with normal control group, the osteocalcin content, ALP activity, Osterix and Runx2 mRNA expression and OPN protein expression increased significantly (P<0.01), and the protein expression of SMα and SM22α reduced dramatically in A7r5 cells of calcification group (P<0.01). After T3 treatment, the osteocalcin content and ALP activity reduced markedly, mRNA expression of Osterix and Runx2 and OPN protein expression reduced significantly. However, MMI (inhibitor of T3) was able to block the above effects of T3. When compared with calcification group, Osterix and Runx2 mRNA expression and OPN protein expression increased markedly (P<0.01). In addition, the protein expression of ERK1/2, p-ERK, Akt and p-Akt increased significantly in calcification group. In the presence of integrin αvβ3/ERK blocker (PD98059) and/or PI3K/Akt antagonist (LY294002), T3 was still able to inhibit the calcification, and this effect was similar to that after treatment with inhibitors alone. Moreover, LY294002 had a better inhibitory effect as compared to PD98059.

Conclusion: T3 may act on PI3K/Akt signaling pathway to inhibit the phenotype transformation of VSMC, which then suppresses the calcium/phosphate induced calcification of rat VSMCs. Thus, T3 is an endogenous molecule that can protect the blood vessels against calcification.

Keywords: Thyroid hormone, vascular calcification, vascular smooth muscle cells, phenotype switch, signaling pathway

Full paper freely available here:

ncbi.nlm.nih.gov/pmc/articl...

[Hillwoman]

Very encouraging that someone is teasing out another protective function of T3, and the processes involved. I don't pretend to understand it all, but thanks for posting.

[helvella Administrator Thyroid UK in reply to Hillwoman]

Nor, I assure you, do I.

From my very first days involved with thyroid issues, I have been trying to understanding what the hormones actually do. We still do not have a full, or even a barely adequate, description.

With a proper undestanding of their interactions we just might be able to work out why their effects are what they are. Why they are so varied both within and between people. What to do to improve treatment.

[silverfox7]

Sort of a double whammy in a way as doctors not brilliant in saying we must take K2 with vit D do how many others have calcium rushing round their blood vessels instead of going to where it is needed!

Thanks for posting

[Bettan]

Thank you for an interesting and informative piece of research on the importance of t3.