VCAM1 and Parkinson disease: Notably, previous studies had found that alterations in serum proline-rich protein 14 (PRR14), vascular cell adhesion molecule-1(VCAM-1), and soluble CD163 (sCD163) levels, were probably linked with the constipation status (4), the severity of disease (5), the cognition levels (6), and so on in patients with PD.