Liposome-encapsulated berberine treatment reduces adverse ventricle remodeling after myocardial infarction

Introduction: Adverse left ventricle remodeling can be measured as a reduction in ejection fraction after myocardial infarction. Left ventricle remodeling leads to congestive heart failure and is a main determinant of mortality and morbidity after myocardial infarction. Berberine is an isoquinoline alkaloid extracted from barberry that has anti-inflammatory and anti-oxidant activities. Pretreatment with long-term administration of high doses of berberine has shown beneficial effects in experimental diabetes and cardiac ischemia reperfusion injury. However, the poor solubility and the short half-life in the circulation have impeded the clinical use of berberine. Purpose: To examine whether encapsulation of berberine into long-circulating liposomes could improve its therapeutic availability and efficacy to protect cardiac function in vivo. Methods: Berberine was loaded into liposomes at a concentration of 0.3 mg/ml. Lipopolysaccharide (LPS) activated mouse macrophages RAW 264.7 were treated with free berberine or liposome-encapsulated berberine (Lipo-Berb) and analyzed for cell viability, reactive oxygen species production and cytokine secretion. C57BL/6J male mice (10-12 week old) subjected to myocardial infarction (MI) via permanent ligation of the left anterior descending artery were blindly selected for intravenous injection of empty liposomes, free berberine or lipo-Berb (1.5 mg/kg). Three doses were administered at the onset of MI, and at 3 and 6 days after MI. Ejection fraction was assessed by echocardiography at baseline, 7 and 28 days after MI. Results: Free berberine improved the viability of LPS-insulted macrophages, reduced production of reactive oxygen species and inhibited the secretion of inflammatory mediators including IL-6 and TNFα. As expected these protective effects of berberine in vitro were diminished upon encapsulation into liposomes. In vivo, however, the liposome-encapsulated berberine significantly preserved ejection fraction after 28 days of MI while free berberine did not show any preservation of ejection fraction (29.5±1.9 for lipo-Berb, 18.2±3.2 for free berberine and 18.0±3.1 for empty liposomes; n=6-10;