Increased levels of serum vasoactive intestinal peptide were found to be associated with acute exacerbations in patients with chronic obstructive pulmonary disease (COPD), according to the findings of a recent study published in the journal Respiration.
Vasoactive intestinal polypeptide (VIP) is a 28-amino acid polypeptide secreted by cells throughout the intestinal tract, and it stimulates the secretion of electrolytes and water by the intestinal mucosa. VIP is also the most abundant neuropeptide in the lung, and has been linked to pulmonary arterial hypertension and hypoxia.
In order to investigate levels of circulating VIP at exacerbation and at stable COPD, and assess the diagnostic presentation in a sample of patients with the disease, Jyotshna Mandal, PhD, from the Clinic of Pulmonary Medicine and Respiratory Cell Research, University Hospital Basel, and colleagues analyzed patients with stage II to stage IV disease as classified by the Global Initiative for Chronic Obstructive Lung Disease. The study is titled “Vasoactive Intestinal Peptide for Diagnosing Exacerbation in Chronic Obstructive Pulmonary Disease.”
The team assessed COPD patients in a stable state and during acute exacerbation of COPD (AE-COPD), and they collected dedicated serum at both times. To determine the levels of serum VIP, the researchers used an enzyme-linked immunosorbent assay.
The results revealed that at baseline, COPD patients with acute exacerbation (n=120) and stable COPD patients (n=163) had identical clinical characteristics. The researchers found no correlation between serum VIP levels and oxygen saturation at rest or during exercise.
The results further showed that serum VIP levels were higher in COPD patients with acute exacerbation in comparison with stable patients. After the researchers included a propensity score matching, the results revealed that the association of increased serum VIP with acute exacerbations remained significant.
Analysis of the Youden index indicated the optimal serum VIP cut-off value as 56.6 pg/ml. The probability of acute exacerbation was found to be very low if the levels of serum VIP were ≤35 pg/ml, and very high if serum VIP were ≥88 pg/ml. Levels of serum VIP were found to present a robust performance to diagnose acute exacerbation of COPD.
Based on these findings, the researchers concluded that increased serum VIP levels are associated with AE-COPD.