Intramyocardial delivery of basic fibroblast growth factor-impregnated gelatin hydrogel microspheres enhances collateral circulation to infarcted canine myocardium

The present study examined whether basic fibroblast growth factor (bFGF)-im pregnated acidic gelatin hydrogel microspheres (AGHM) would enhance collate ral development to the infarct area in dogs with coronary occlusion. Studie s were conducted in 28 jogs with a 2-week occlusion of the proximal left an terior descending coronary artery (LAD). The dogs were divided into a group s according to treatment: Group A treated with bFGF-impregnated AGHM in the infarct area; Group B with free-form bFGF; Group C with AGHM alone. Corona ry angiography (n=15; Group A, 7 dogs; Group B, 5 dogs; Group C, 3 dogs) an d a regional myocardial blood flow study (n=13; Group A, 6 dogs: Group B, 4 dogs; Group C, 3 dogs) were repeated at a 2-week interval. Coronary angiog raphy revealed that in Group A, antegrade flow in the LAD distal to the occ lusion, which was assessed by Thrombolysis in Myocardial Infarction (TIMI) grade, was significantly increased after treatment. In contrast, in Groups B and C, the treatment did not change the how grade in the LAD. In Group 4, the regional myocardial blood how in the collateral dependent area was sig nificantly increased after treatment, and the regional myocardial blood flo w reserve after adenosine injection was also significantly increased. These measurements remained after treatment in Groups B and C, The immunohistoch emical study with factor VIII-related antigen revealed an increase of vascu lar density in the ischemic region in Group A. Intramyocardial delivery of bFGF-impregnated AGHM, but not free-form bFGF, improves the collateral circ ulation to the infarct area of a coronary occlusion in dogs.