Background: The aim was to investigate the role of biomarkers of endothelial dysfunction in formation of osteoporosis in the patients with chronic obstructive pulmonary disease (COPD).
Methods: Soluble E-selectin, endotheline 1 (ET-1), vitamin D, vascular endothelial growth factor (VEGF), metalloproteinase-9 (MMP-9), vascular cell adhesion molecule (VCAM-1), osteoprotegerin (OPG), the receptor activator of nuclear factor-kB ligand (RANKL) and bone biomarkers were determined in 63 patients with COPD. BMD was measured by DEXA at the lumbar spine (LS) and left femur neck (FN).
Results: Circulating bone formation markers (procollagen type 1 amino-terminal propeptide P1NP), N-terminal midmolecule fragment osteocalcin (N-MID OC) and bone specific alkaline phosphatase was lower in COPD than in the controls. Type 1 collagen C-telopeptide (CTx-bone resorption marker) was higher in lung group and was inversely related to FN (r=-0,43, p<0,05) and had a direct relationship with P1NP (r=0,63, p<0,01). The E-selectin, endotheline 1 (ET-1), TNF-a, IL-6, VEGF, RANKL, MMP-9 and VCAM-1 were higher; Vitamin D, OPG were low in lung pathology than in controls. Compared with the lung group with osteopenia, levels of E-selectin, TNF-a, ET-1, MMP-9 and VEGF were the highest in COPD with osteoporosis. There was positive correlation between vitamin D, OPG (r=0,51, p<0,001; r=0,57, p<0,001) and negative one between TNF-a (r=-0,44, p<0,01), MMP-9 (r=-0,46, p<0,01) and BMD in FN and LS; inverse correlation between ET-1 (r=-0.56, p<0,01), VEGF (r=-0.64, p<0,001) in L2-L4 only; negative correlation of VCAM-1 and TNF-a with BMD in FN only. OPG was correlated with N-MID OC (r=0,53, p<0,001), RANKL (r=-0,44, p<0,01) and TNF-a in lung patients. No correlations were found between VCAM-1, IL-6 and markers of bone metabolism. ET-1, MMP-9 and VEGF significantly positively correlated with parameters of bone resorption and negatively associated with P1NP and N-MID OC.
Conclusion: A significant association between parameters of bone metabolism and endothelial dysfunction markers in COPD patients with osteoporosis, which suggests possible role of endothelial dysfunction in the increasing of bone loss in COPD.
Disclosure: The authors declared no competing interests.