COMMD5 is involved in the mechanisms of hypotension after parathyroidectomy in patients receiving hemodialysis.

Background: Secondary hyperparathyroidism (SHPT) is a common complication of end-stage renal disease. Parathyroidectomy (PTx) is often employed for treatment of severe SHPT. However, PTx may cause hypotension via unknown mechanisms. COMM domain-containing protein 5 (COMMD5) in the parathyroid glands has been linked to blood pressure regulation of spontaneously hypertensive rats.

Objective: To explore the relationship between COMMD5 levels and reduced BP after PTx in patients receiving hemodialysis (HD).

Methods And Results: (1) The study cohort included 31 patients receiving HD who underwent PTx. Serum COMMD5 levels were higher post-PTx vs. pre-PTx. (2) Sprague-Dawley rats (n = 22) were assigned to a 5/6 nephrectomy group or sham surgery group, vascular rings of the thoracic aorta from rats with CKD were incubated with COMMD5, and changes in vascular tension were compared. COMMD5 inhibited vasoconstriction of vascular rings with intact endothelium, but had no effect on vascular rings without the endothelium. (3) Human umbilical vein endothelial cells were stimulated with COMMD5 or small interfering RNA (siRNA). The expression levels of atrial natriuretic peptide (ANP) and endothelial nitric oxide synthase (eNOS) were up-regulated and down-regulated, respectively.

Conclusions: Serum COMMD5 levels were increased after PTx in SHPT patients. COMMD5 promoted high expression of ANP and eNOS in endothelial cells, leading to vasodilation and resulting in hypotension.