Background: Chronic obstructive pulmonary disease (COPD) is a chronic airway inflammatory disease characterized by irreversible airflow obstruction. Pathogenic mechanisms underlying COPD remain largely unknown.
Objective: The current study was designed to explore serum concentration of hypoxia-inducible factor 1α (HIF-1α) in stable COPD patients and the potential effect of Lycium barbarum  polysaccharides (LBP) on HIF-1α protein expression.
Methods: Serum HIF-1α was quantified by ELISA in 102 stable COPD patients before and after 2-week orally taken LBP (100 mL/time, twice daily, 5– 15 mg/mL). Correlation of serum LBP and lung function (FEV1%) or blood gas (PO₂ and PCO₂) was also analyzed. As a control, 105 healthy subjects were also enrolled into this study.
Results: Serum concentration of HIF-1α was significantly higher in the stable COPD patients (37.34 ± 7.20 pg/mL) than that in the healthy subjects (29.55 ± 9.66 pg/mL, P < 0.001). Oral administration of LBP (5 mg/mL, 100 mL, twice daily for 2 weeks) not only relieved COPD symptoms but also significantly reduced serum HIF-1α concentration (36.94 ± 9.23 vs 30.49 ± 6.42 pg/mL, P < 0.05). In addition, level of serum HIF-1α concentration was significantly correlated with PCO₂ (r = 0.283, P < 0.001), but negatively and significantly correlated with PO₂ (r = − 0.490, P =0.005) or FEV1%(r = − 0.420, P =0.018).
Conclusion: These findings suggested that activation of HIF-1 signaling pathway may be involved in the pathophysiology of COPD and that stabilization of serum HIF-1α concentration by LBP might benefit the stable COPD patients.
Keywords: chronic obstructive pulmonary disease, COPD, hypoxia-induced factor 1, HIF-1, Lycium barbarum  polysaccharides, LBP