The Anti-Inflammatory Effects and Clinical Potential of Dexmedetomidine in Pulmonary Arterial Hypertension

J Pharmacol Exp Ther. 2023 May;385(2):88-94. doi: 10.1124/jpet.122.001399. Epub 2023 Feb 27.

Abstract

A pathogenic aspect of pulmonary arterial hypertension (PAH) is the aberrant pulmonary arterial smooth muscle cell (PASMC) proliferation. PASMC proliferation is significantly affected by inflammation. A selective α-2 adrenergic receptor agonist called dexmedetomidine (DEX) modulates specific inflammatory reactions. We investigated the hypothesis that anti-inflammatory characteristics of DEX could lessen PAH that monocrotaline (MCT) causes in rats. In vivo, male Sprague-Dawley rats aged 6 weeks were subcutaneously injected with MCT at a dose of 60 mg/kg. Continuous infusions of DEX (2 µg/kg per hour) were started via osmotic pumps in one group (MCT plus DEX group) at day 14 following MCT injection but not in another group (MCT group). Right ventricular systolic pressure (RVSP), right ventricular end-diastolic pressure (RVEDP), and survival rate significantly improved in the MCT plus DEX group compared with the MCT group [RVSP, 34 mmHg ± 4 mmHg versus 70 mmHg ± 10 mmHg; RVEDP, 2.6 mmHg ± 0.1 mmHg versus 4.3 mmHg ± 0.6 mmHg; survival rate, 42% versus 0% at day 29 (P < 0.01)]. In the histologic study, the MCT plus DEX group showed fewer phosphorylated p65-positive PASMCs and less medial hypertrophy of the pulmonary arterioles. In vitro, DEX dose-dependently inhibited human PASMC proliferation. Furthermore, DEX decreased the expression of interleukin-6 mRNA in human PASMCs treated with fibroblast growth factor 2 (FGF2). These consequences suggest that DEX improves PAH by inhibiting PASMC proliferation through its anti-inflammatory properties. Additionally, DEX may exert anti-inflammatory effects via blocking FGF2-induced nuclear factor κ B activation. SIGNIFICANCE STATEMENT: Dexmedetomidine, a selective α-2 adrenergic receptor agonist utilized as a sedative in the clinical setting, improves pulmonary arterial hypertension (PAH) by inhibiting pulmonary arterial smooth muscle cell proliferation through its anti-inflammatory effect. Dexmedetomidine may be a new PAH therapeutic agent with vascular reverse remodeling effect.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic Agonists / adverse effects
  • Animals
  • Anti-Inflammatory Agents / pharmacology
  • Anti-Inflammatory Agents / therapeutic use
  • Dexmedetomidine* / pharmacology
  • Dexmedetomidine* / therapeutic use
  • Disease Models, Animal
  • Fibroblast Growth Factor 2 / metabolism
  • Humans
  • Hypertension, Pulmonary* / chemically induced
  • Hypertension, Pulmonary* / drug therapy
  • Hypertension, Pulmonary* / pathology
  • Inflammation / metabolism
  • Male
  • Monocrotaline / adverse effects
  • Monocrotaline / metabolism
  • Myocytes, Smooth Muscle / metabolism
  • Pulmonary Arterial Hypertension* / drug therapy
  • Pulmonary Artery
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Dexmedetomidine
  • Fibroblast Growth Factor 2
  • Monocrotaline
  • Anti-Inflammatory Agents
  • Adrenergic Agonists