Circulating surfactant protein D as a potential lung-specific biomarker of health outcomes in COPD: a pilot study

Abstract

BackgroundThere is a paucity of surrogate lung-specific biological markers that can be used to track disease progression and predict clinical outcomes in chronic obstructive pulmonary disease (COPD). The principal aim of this pilot study was to determine whether circulating surfactant protein D (SPD) or Clara Cell protein-16 (CC16) levels are associated with lung function or health status in patients with severe COPD.MethodsWe studied 23 patients with advanced COPD. Lung function measurements, Chronic Respiratory Disease Questionnaire (CRQ) scores, and serum levels of SPD, CC16, and C-reactive protein (CRP) were determined at baseline and at 3 months.ResultsAt baseline, FEV1 was inversely associated with serum SPD levels (P = 0.045) but not with CC16 (P = 0.675) or CRP levels (P = 0.549). Over a 3 month period, changes in SPD levels correlated significantly with changes in CRQ scores (adjusted P = 0.008) such that patients who had the largest declines in serum SPD levels experienced the largest gains in health status. The association was particularly notable between circulating SPD level and the dyspnea domain of the CRQ score (P = 0.018). Changes in CC16 or CRP levels did not correlate with changes in CRQ scores.ConclusionChanges in serum SPD levels tracked well with changes in health status over a 3 month period in patients with severe COPD. These data suggest that circulating SPD levels may be useful biomarkers to track health outcomes of COPD patients.

Systemic manifestations and comorbidities of COPD

“…Serum SP-D concentrations are increased in patients with COPD and are better related to disease severity and symptoms than CRP [36]. Since SP-D is derived only from peripheral lung tissue it provides good evidence that lung inflammation can lead to inflammatory changes in the systemic circulation rather than vice versa.…”

Gene promoter methylation is associated with lung function in the elderly: The normative aging study

“…However, a recent study found elevated circulating levels of surfactant protein D, which is specific from lung tissues and therefore provides more evidence for the overspill hypothesis. 53,54 mechanisms responsible for decreased lung function, including in persons free of COPD. Previous work in this cohort has shown that statin use, which in addition to lowering cholesterol has antioxidant activity, was associated with higher than predicted lung function, independent of chronic respiratory disease.…”

Significance of surfactant proteins in the diagnosis of therapeutic diseases

“…У пациентов с ХОБЛ, получавших терапию ингаляционными глюкокортикостероидами, наблюдался более высокий уровень SP-D (в сыворотке и мокроте), чем у пациентов без лечения. При этом у пациентов с повышенным уровнем SP-D в сыворотке кро-ви отмечена более высокая частота обострений в течение 6 мес (р=0,0001; r=0,59) [50].…”