EETs Elicit Direct Increases in Pulmonary Arterial Pressure in Mice

Area of Science:

• Cardiovascular Physiology
• Pulmonary Circulation
• Vascular Biology

Background:

• The precise role of epoxyeicosatrienoic acids (EETs) in regulating pulmonary circulation remains unclear.
• EETs are known vasoactive lipids, but their specific impact on right ventricular systolic pressure (RVSP) is debated.

Purpose of the Study:

• To investigate the hypothesis that EETs elevate RVSP, possibly through pulmonary vasoconstriction.
• To elucidate the direct effects of EETs on RVSP independent of systemic blood pressure changes.

Main Methods:

• Anesthetized mice were instrumented with catheters for infusing EETs, monitoring blood pressure (BP), and RVSP.
• Four regioisomeric EETs were administered at various doses, and responses were recorded under basal and hypoxic conditions.
• Direct right ventricular injections of 14,15-EET were performed to assess RVSP changes independently of systemic BP.

Main Results:

• All tested EETs induced dose-dependent increases in RVSP with concurrent decreases in BP.
• 11,12-EET demonstrated the most significant increase in RVSP.
• Direct right ventricular administration of 14,15-EET elevated RVSP without affecting systemic BP, confirming a direct pulmonary effect.
• Hypoxia exposure potentiated both basal RVSP and EET-induced increases in RVSP.

Conclusions:

• EETs directly increase RVSP, suggesting a significant role in pulmonary circulation regulation.
• This EET-mediated elevation of RVSP may be a key factor in the pathogenesis of hypoxia-induced pulmonary hypertension (PH).