A targeted high-efficiency angiogenesis strategy as therapy for myocardial infarction

The aim of this study was to prove that an intramyocardial injection of a mixture of low-dose human growth factor (HGF) plasmid and microbubbles (MB) in combination with insonation was an effective therapy for myocardial infarction.

Twenty dogs with myocardial infarction were divided into 4 groups: (1) HGF, MB and ultrasound (HGF-US/MB), (2) HGF and US (HGF-US), (3) HGF alone and (4) surgery alone (control). In the HGF-US/MB group, HGF plasmid DNA (500 μg) mixed with 0.5 ml of MB solution was injected 5 min after coronary occlusion followed by insonation. With the exception of the control group, the other dogs were divided into two groups, one treated with the HGF gene and insonation and the other with the HGF gene only.

Compared to the HGF group, infarct size decreased from 32%±7% (control) to 23%±5% in the HGF-US/MB group 28 d later (P<0.05). Capillary density increased from 21.7±4.2/mm(2) (control) to 114.3±28.9/mm(2) in the HGF-US/MB group (P<0.01). Compared to the HGF group, there was a 14% decrease in the ratio of left ventricle weight/body weight and a 25% decrease in hydroxyproline content. We also observed a 29% and 20% decrease in collagen volume fraction of type I and type III collagen, respectively in the HGF-US/MB group.

Intramyocardial injection of HGF and MB in combination with insonation enhances neovascularization and reduces ventricular remodeling and infarct size.