Serum neopterin (NP) concentration is elevated in patients with pulmonary arterial hypertension (PAH) and patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH) and is associated with adverse clinical outcomes, according to the results of a prospective study conducted in Poland published in Respiration.
Researchers sought to evaluate the effect of NP on outcomes and the association with disease severity in patients with PAH and CTEPH. Serum levels of NP were analyzed prospectively in a total of 50 patients (36 with PAH and 14 with CTEPH) vs 31 healthy controls and assessed relative to clinical parameters and outcomes.
The concentration of NP in the PAH and CTEPH groups combined was significantly higher than that in the control group (8.68 nmol/L [range, 6.39-15.03 nmol/L] vs 5.14 nmol/L [range, 4.16-5.98 nmol/L], respectively; P <.0000001). During 9 months of follow-up, clinical deterioration (including 8 deaths) was reported in 18 patients, with NP levels in this group higher than those in stable patients (15.6 nmol/L [range, 8.52-25.13 nmol/L] vs 7.87 nmol/L [range, 6.18-9.89 nmol/L], respectively; P =.002).
On Cox regression analysis, NP level was predictive of clinical deterioration (95% CI, 1.01-1.06; P =.009). Moreover, NP was positively correlated with N-terminal pro-brain natriuretic peptide (P <.001), red blood cell distribution width (P <.001), and right atrium area (P =.002). In contrast, NP was inversely correlated with 6-minute walking (P =.002) and peak oxygen consumption (P =.001) test results.
The investigators concluded that the results of their analysis confirmed the important involvement of sustained immune activation, particularly of macrophages, in patients with PAH and inoperable CTEPH progression. Thus, NP may serve as a candidate predictive biomarker of disease severity and clinical worsening in patients with PAH and CTEPH deterioration.
Smukowska-Gorynia A, Marcinkowska J, Chmara E, et al. Neopterin as a biomarker in patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension [published online June 15, 2018]. Respiration. doi:10.1159/000488908