Abstract: Objective:To investigate the relationship between COMM domain protein 5 （ COMMD5）  and vascular calcification （ VC）  in patients with chronic kidney disease （ CKD）.    Methodology:Bioinformatics analysis was conducted to explore the relationship between COMMD5 and vascular calcification in CKD patients. Vascular rings from CKD calcified patients and control groups were stained with Alizarin red and subjected to immunohistochemistry.  Human vascular smooth muscle cells （ HVSMC）  were stimulated with high phosphate to observe COMMD5 expression.  COMMD5 small interfering RNA （ siRNA）  was used in vitro to examine the expression levels of Runt⁃related transcription factor 2 （ RUNX2）， smooth muscle antibody （ α⁃SMA）， and cytoskeleton⁃associated protein （ SM22α）. COMMD5 recombinant protein was also used to stimulate HVSMCs， and Alizarin red staining was performed to assess the effects.    Results:Bioinformatics analysis showed that COMMD5 was related to vascular  calcification， and compared with the  control  group， the  expression of  COMMD5  in the vascular  calcification  group  was  down⁃regulated  （ P < 0.05）.  Compared  with  the  normal  group，  the  expression  of COMMD5 was downregulated in patients with vascular calcification in CKD patients（ P<0.01）. The expression of COMMD5 in human aortic smooth muscle cells  stimulated  by  high  phosphorus  was  lower  than  that  in  the  control  group  （ P< 0.05）. SiRNA of COMMD5 and high phosphorus were used to stimulate HVSMCs， resulting in up⁃regulation of RUNX2 expression and down⁃regulation of SM22α  expression  （ P < 0.05）.  COMMD5  recombinant  protein  incubation  in  HVSMC  resulted  in decreased Alizarin  red  staining  in  the  high  phosphate  and  COMMD5  recombinant  protein  group  compared  to  the  high phosphate group.    Conclusion:COMMD5 is associated with vascular  calcification and alleviates  high phosphorus⁃induced calcification in HVSMC.

Key words:  vascular calcification ,  COMM domain?containing protein 5,  human vascular smooth muscle cells