Reduction in circulating Endothelin-1 levels by inhaled COPD medications

Area of Science:

• Pulmonary Medicine
• Pharmacology
• Molecular Biology

Background:

• Pulmonary hypertension (PH) complicates chronic obstructive pulmonary disease (COPD), worsening prognosis and quality of life.
• Endothelin-1 (ET-1) plays a role in PH development and is elevated in COPD patients.
• The effect of inhaled COPD treatments on ET-1 levels and COPD-related PH is not well understood.

Purpose of the Study:

• To investigate changes in plasma endothelin-1 (ET-1) levels following administration of inhaled COPD medications.
• To explore the underlying mechanisms by which COPD treatments may affect ET-1 levels.

Main Methods:

• 33 COPD patients underwent pulmonary function tests and plasma ET-1 measurements before and after 4-12 weeks of inhaled treatment.
• An animal model of emphysema was treated with budesonide/glycopyrronium/formoterol (BUD/GLY/FOR) combination therapy.
• ET-1 concentration and cytokine expression (TNFα) were analyzed in mice; ET-1 expression was examined in HULEC-5a cells stimulated with TNFα.

Main Results:

• COPD patients exhibited higher baseline plasma ET-1 levels compared to controls, which decreased significantly after treatment.
• In mice, BUD/GLY/FOR treatment reduced elevated ET-1 levels and TNFα expression.
• TNFα stimulation upregulated ET-1 expression in HULEC-5a cells, indicating a link between inflammation and ET-1.

Conclusions:

• Conventional inhaled COPD therapies decrease plasma ET-1 concentration in COPD patients.
• The anti-inflammatory effects of inhaled medications, demonstrated by reduced TNFα expression in mouse models, likely mediate the suppression of ET-1.
• These findings suggest that inhaled COPD treatments may mitigate COPD-related PH by reducing ET-1 levels through anti-inflammatory mechanisms.