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Gene therapy in a humanized mouse model of familial hypercholesterolemia leads to marked regression of atherosclerosis.

Kassim SH, Li H, Vandenberghe LH, Hinderer C, Bell P, Marchadier D, Wilson A, Cromley D, Redon V, Yu H, Wilson JM, Rader DJ - PLoS ONE (2010)

Bottom Line: A single intravenous injection of AAV8.mLDLR was found to significantly reduce plasma cholesterol and non-HDL cholesterol levels in chow-fed animals at doses as low as 3×10(9) genome copies/mouse.Collectively, the results presented herein suggest that AAV8-based gene therapy for FH may be feasible and support further development of this approach.The pre-clinical data from these studies will enable for the effective translation of gene therapy into the clinic for treatment of FH.

View Article: PubMed Central - PubMed

Affiliation: Gene Therapy Program, Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.

ABSTRACT

Background: Familial hypercholesterolemia (FH) is an autosomal codominant disorder caused by mutations in the low-density lipoprotein receptor (LDLR) gene. Homozygous FH patients (hoFH) have severe hypercholesterolemia leading to life threatening atherosclerosis in childhood and adolescence. Mice with germ line interruptions in the Ldlr and Apobec1 genes (Ldlr(-/-)Apobec1(-/-)) simulate metabolic and clinical aspects of hoFH, including atherogenesis on a chow diet.

Methods/principal findings: In this study, vectors based on adeno-associated virus 8 (AAV8) were used to deliver the gene for mouse Ldlr (mLDLR) to the livers of Ldlr(-/-)Apobec1(-/-) mice. A single intravenous injection of AAV8.mLDLR was found to significantly reduce plasma cholesterol and non-HDL cholesterol levels in chow-fed animals at doses as low as 3×10(9) genome copies/mouse. Whereas Ldlr(-/-)Apobec1(-/-) mice fed a western-type diet and injected with a control AAV8. vector experienced a further 65% progression in atherosclerosis over 2 months compared with baseline mice, Ldlr(-/-)Apobec1(-/-) mice treated with AAV8.mLDLR realized an 87% regression of atherosclerotic lesions after 3 months compared to baseline mice. Immunohistochemical analyses revealed a substantial remodeling of atherosclerotic lesions.

Conclusions/significance: Collectively, the results presented herein suggest that AAV8-based gene therapy for FH may be feasible and support further development of this approach. The pre-clinical data from these studies will enable for the effective translation of gene therapy into the clinic for treatment of FH.

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Immunohistochemical analysis of mouse atherosclerotic lesions.Representative aortic root sections immunostained for the foam cell marker CD68 (A), VCAM-1 (B), or Masson trichrome blue stain for collagen content (C). Original magnification, 40×. Note abundant immunostaining for foam cell marker, CD68 (brown), VCAM-1 adhesion molecules (also brown), and presence of collagen αblue) within lesion in baseline and AAV.TBG.nLacZ injected Ldlr-/-Apobec1-/-animals.
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pone-0013424-g006: Immunohistochemical analysis of mouse atherosclerotic lesions.Representative aortic root sections immunostained for the foam cell marker CD68 (A), VCAM-1 (B), or Masson trichrome blue stain for collagen content (C). Original magnification, 40×. Note abundant immunostaining for foam cell marker, CD68 (brown), VCAM-1 adhesion molecules (also brown), and presence of collagen αblue) within lesion in baseline and AAV.TBG.nLacZ injected Ldlr-/-Apobec1-/-animals.

Mentions: For further assessment of lesion remodeling, immunostaining was performed on fresh-frozen sections of the aortic root. Samples were examined for CD68, a foam cell marker (Fig. 6A), VCAM-1, an adhesion molecule that plays a role in atherosclerotic lesion formation (Fig. 6B), and collagen, a molecule that determines the mechanical stability of atherosclerotic plaques (Fig. 6C). Lesions in baseline treated groups were advanced, with many necrotic centers, CD68+ macrophages and macrophage-derived foam cells, and extensive VCAM-1 and collagen in the expanded neointima (Fig. 5F and 6A–6C) These results demonstrate the complexity of the lesions in the pre-injected aorta (i.e., that they had progressed past the early macrophage foam cell stage). AAV8.TBG.nLacZ treated animals displayed similar advanced pathology. In contrast, AAV8.TBG.mLDLR treated mice had much smaller lesions with decreased areas of CD68, VCAM-1, and collagen immunostaining in the intima and media. These results indicate a change in smooth muscle cell phenotype that is part of the wide-scale remodeling process that occurred during the 2 months in which systemic lipid levels where normalized.


Gene therapy in a humanized mouse model of familial hypercholesterolemia leads to marked regression of atherosclerosis.

Kassim SH, Li H, Vandenberghe LH, Hinderer C, Bell P, Marchadier D, Wilson A, Cromley D, Redon V, Yu H, Wilson JM, Rader DJ - PLoS ONE (2010)

Immunohistochemical analysis of mouse atherosclerotic lesions.Representative aortic root sections immunostained for the foam cell marker CD68 (A), VCAM-1 (B), or Masson trichrome blue stain for collagen content (C). Original magnification, 40×. Note abundant immunostaining for foam cell marker, CD68 (brown), VCAM-1 adhesion molecules (also brown), and presence of collagen αblue) within lesion in baseline and AAV.TBG.nLacZ injected Ldlr-/-Apobec1-/-animals.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2957433&req=5

pone-0013424-g006: Immunohistochemical analysis of mouse atherosclerotic lesions.Representative aortic root sections immunostained for the foam cell marker CD68 (A), VCAM-1 (B), or Masson trichrome blue stain for collagen content (C). Original magnification, 40×. Note abundant immunostaining for foam cell marker, CD68 (brown), VCAM-1 adhesion molecules (also brown), and presence of collagen αblue) within lesion in baseline and AAV.TBG.nLacZ injected Ldlr-/-Apobec1-/-animals.
Mentions: For further assessment of lesion remodeling, immunostaining was performed on fresh-frozen sections of the aortic root. Samples were examined for CD68, a foam cell marker (Fig. 6A), VCAM-1, an adhesion molecule that plays a role in atherosclerotic lesion formation (Fig. 6B), and collagen, a molecule that determines the mechanical stability of atherosclerotic plaques (Fig. 6C). Lesions in baseline treated groups were advanced, with many necrotic centers, CD68+ macrophages and macrophage-derived foam cells, and extensive VCAM-1 and collagen in the expanded neointima (Fig. 5F and 6A–6C) These results demonstrate the complexity of the lesions in the pre-injected aorta (i.e., that they had progressed past the early macrophage foam cell stage). AAV8.TBG.nLacZ treated animals displayed similar advanced pathology. In contrast, AAV8.TBG.mLDLR treated mice had much smaller lesions with decreased areas of CD68, VCAM-1, and collagen immunostaining in the intima and media. These results indicate a change in smooth muscle cell phenotype that is part of the wide-scale remodeling process that occurred during the 2 months in which systemic lipid levels where normalized.

Bottom Line: A single intravenous injection of AAV8.mLDLR was found to significantly reduce plasma cholesterol and non-HDL cholesterol levels in chow-fed animals at doses as low as 3×10(9) genome copies/mouse.Collectively, the results presented herein suggest that AAV8-based gene therapy for FH may be feasible and support further development of this approach.The pre-clinical data from these studies will enable for the effective translation of gene therapy into the clinic for treatment of FH.

View Article: PubMed Central - PubMed

Affiliation: Gene Therapy Program, Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.

ABSTRACT

Background: Familial hypercholesterolemia (FH) is an autosomal codominant disorder caused by mutations in the low-density lipoprotein receptor (LDLR) gene. Homozygous FH patients (hoFH) have severe hypercholesterolemia leading to life threatening atherosclerosis in childhood and adolescence. Mice with germ line interruptions in the Ldlr and Apobec1 genes (Ldlr(-/-)Apobec1(-/-)) simulate metabolic and clinical aspects of hoFH, including atherogenesis on a chow diet.

Methods/principal findings: In this study, vectors based on adeno-associated virus 8 (AAV8) were used to deliver the gene for mouse Ldlr (mLDLR) to the livers of Ldlr(-/-)Apobec1(-/-) mice. A single intravenous injection of AAV8.mLDLR was found to significantly reduce plasma cholesterol and non-HDL cholesterol levels in chow-fed animals at doses as low as 3×10(9) genome copies/mouse. Whereas Ldlr(-/-)Apobec1(-/-) mice fed a western-type diet and injected with a control AAV8. vector experienced a further 65% progression in atherosclerosis over 2 months compared with baseline mice, Ldlr(-/-)Apobec1(-/-) mice treated with AAV8.mLDLR realized an 87% regression of atherosclerotic lesions after 3 months compared to baseline mice. Immunohistochemical analyses revealed a substantial remodeling of atherosclerotic lesions.

Conclusions/significance: Collectively, the results presented herein suggest that AAV8-based gene therapy for FH may be feasible and support further development of this approach. The pre-clinical data from these studies will enable for the effective translation of gene therapy into the clinic for treatment of FH.

Show MeSH
Related in: MedlinePlus