February 2021 Virtual Meeting

Speaker: Allen Everett, Johns Hopkins University

Topic: Proteomics Discovery of Circulating Pulmonary Hypertension Biomarkers: IGF binding proteins are associated with disease severity

Date: Monday, February 15th, 2021

Time: 1:00 PM Presentation

Location: Webinar – see emails on Feb. 4 and 11 for invite link. Join the mailing list

Background: Pulmonary arterial hypertension is a progressive and fatal disease characterized by sustained elevations of pulmonary artery pressure. We lack circulating, diagnostic and prognostic markers to improve outcomes and develop new therapies.
Methods and Results: We performed proteomics discovery using high resolution mass spectrometry to identify new circulating biomarkers of pulmonary arterial hypertension. Plasma samples from patients with idiopathic pulmonary arterial hypertension (N=9, age 35.2 ± 11.2 years, 89% female) and normal controls (N=9, age 34.8 ± 10.6 years, 100% female) were processed by liquid chromatography/tandem mass spectrometry. A total of 826 (0.047 False Discovery Rate) idiopathic pulmonary arterial hypertension and 461 (0.087 False Discovery Rate) control proteins were identified. By Volcano plot, 153 proteins showed > 2 fold change, P<0.05. Carbonic anhydrase 2 (CA2) and Insulin like growth factor binding protein (IGFBP2) were top molecules by spectral counts. When all IGF axis molecules were examined, spectral counts for IGF1, IGF2, IGFBP1, IGFBP4, and IGFBP7 were also different between PAH and control. ELISA verification (N=41 PAH and N=39 controls) demonstrated that IGF1 and 2 were decreased and IGFBP1, 2, 4, 5, 7 and CA2 were increased in PAH. In association with disease severity, IGFBP2, 4 and 7 were associated with decreased 6MWD and IGFBP1, 2, 5 associated with PVR. IGFBP2, 4, and 7 were associated with survival (Kaplan Meier). CA2 was not associated with clinical severity.
Conclusions: We identified candidate plasma proteins that can distinguish PAH from control and verified CA2 and multiple members of the IGF axis associated with PAH and PAH severity. Suggesting that the IGF axis may play an important role in PAH pathogenesis and may be an important diagnostic for PAH, response to therapy and play a role in the pathogenesis of PAH.