Section Review: Cardiovascular & Renal: Genetic therapies for vascular diseases and lipid disorders

New prospects for cardiovascular gene therapy

Cardiovascular gene therapy has been hampered by the lack of suitable gene delivery vectors for in vivo applications. Low transduction efficiencies, lack of persistent transgene expression and undesirable inflammatory and immune responses have limited the prospects for human gene therapy in the cardiovascular system. New prospects for cardiovascular gene therapy are a result of recent vector developments, in particular with the use of adeno-associated virus (AAV) based vectors in the heart and peripheral vasculature.

The delivery of angiogenic factors to the heart by microsphere therapy

Microspheres offer the possibility of local noninvasive delivery of drugs over an extended period of time. We adsorbed fibroblast growth factor (FGF) to microspheres of precapillary size that were injected via a coronary catheter. We showed that FGF was released from these microspheres and taken up by endothelial cells, which proliferated following translocation of FGF to the nucleus. This method for application of growth factors allows the precise delivery of angiogenic substances to any selected part of the heart or other organs without causing inflammation or ischemia.

Potential gene therapy for lecithin-cholesterol acyltransferase (LCAT)-deficient and hypoalphalipoproteinemic patients with adenovirus-mediated transfer of human LCAT gene

BACKGROUND

Overexpression of human lecithin-cholesterol acyltransferase (LCAT) in transgenic mice results in an increase of the antiatherogenic HDLs.

METHODS AND RESULTS

To investigate the potential use of LCAT for gene therapy, a recombinant adenovirus was constructed in which the human LCAT cDNA was expressed under the control of the human cytomegalovirus immediate/early promoter followed by a chimeric intron (AdCMV human LCAT). Human apolipoprotein (apo) A-I transgenic mice infected with AdCMV human LCAT by intravenous injection accumulated reactive LCAT in the plasma. LCAT activity was increased 201-fold in the plasma of mice infected with 1 x 10(6) pfu AdCMV human LCAT, from 45 +/- 2 to 9068 +/- 812 nmol.mL-1.h-1, in comparison with basal LCAT activity measured in control mice, 5 days after injection. Plasma HDL cholesterol levels rose from 117 +/- 12 to 797 +/- 48 mg/dL, and plasma human apo A-I concentrations increased from 247 +/- 14 to 616 +/- 17 mg/dL, in AdCMV human LCAT infected mice compared with control mice. HDL particles were larger and had a different electrophoretic mobility. Studies of cholesterol efflux by incubation of serum with cholesterol-loaded Fu5AH cells showed that serum from AdCMV human LCAT-infected mice promoted a significantly higher efflux than did that of the controls.

CONCLUSIONS

These data establish the potential of this approach for treatment of subjects with LCAT gene defects as well as patients with low plasma levels of apo A-I and HDL cholesterol.