Liposome-Entrapped Antifibrotic Agent Prevents Collagen Accumulation in Hypertensive Pulmonary Arteries of Rats

We studied the therapeutic efficacy of an intravenously injected antifibrotic agent encapsulated in liposomes on inhibiting collagen accumulation in hypertensive blood vessels. cis-4-Hydroxy-l-proline (cHyp) in liposomes was injected into rats exposed to 10% O2, and drug effect was evaluated by measuring right ventricular pressure and hydroxyproline content of the pulmonary artery. Right ventricular pressure was 11 ± 1 mm Hg (mean ± SEM) 5 days after a single intravenous injection of 200 mg/kg cHyp in liposomes compared with 14 ± 1 mm Hg in rats injected with empty liposomes; hydroxyproline content was also reduced by cHyp treatment (87 ± 6 versus 107 ± 7 μg per vessel) (p