High mobility group box 1 attenuates aortic stenosis by modulating macrophages to reduce valvular calcification

Our previous study demonstrated that HMGB1 may suppress M1 macrophage polarisation and mitigate the progression of calcific aortic valve disease (CAVD). However, the role of HMGB1 in regulating macrophage-mediated valvular calcifi­cation remains to be further explored.

Serum samples from healthy individuals and CAVD patients with varying severity were collected and analysed by ELISA. Immunofluorescence staining of human heart tissue arrays assessed macrophage infiltration in calcified valves. A macro­phage-aortic valve interstitial cell (haVIC) co-culture system was used to examine the effects of reHMGB1-treated macrophages. RUNX2 and osteopontin mRNA expression were measured by RT-qPCR, and alkaline phosphatase (ALP) staining was performed to evaluate calcification.

HMGB1 levels were significantly reduced in severe CAVD patients than controls. Immunofluorescence staining revealed increased CD68 expression in calcified valve samples, indicating macrophage infiltration. In the macrophage-haVIC co-culture system, macrophages pretreated with reHMGB1 led to reduced RUNX2 mRNA expression and lower ALP activity in haVICs, suggesting a potential inhibitory effect of HMGB1 on valvular calcification.

HMGB1 may have the potential to suppress inflammation and mitigate aortic valve calcification, making it a promising therapeutic target for preventing the progression of aortic stenosis.