Donate Help Contact The AHA Sign In Home
American Heart Association
Circulation
Search: search_blue_button Advanced Search
« Previous Article | Table of Contents | Next Article »
Circulation. 1996;94:2046-2051

This Article
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Leiden, J. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Leiden, J. M.

(Circulation. 1996;94:2046-2051.)
© 1996 American Heart Association, Inc.

Articles

Adenovirus-Mediated Gene Transfer as an In Vivo Probe of Lipoprotein Metabolism

Jeffrey M. Leiden, MD, PhD

the Departments of Medicine and Pathology, University of Chicago (Ill).

Correspondence to Jeffrey M. Leiden, MD, PhD, Department of Medicine, University of Chicago, 5841 S Maryland Ave, Chicago, IL 60637.


Key Words: Editorials • genes • lipoproteins • cholesterol


*    Introduction
up arrowTop
 *Introduction
down arrowReferences
 
Numerous epidemiological studies over the past 20 years have taught us that there is a strong inverse correlation between the levels of serum HDL-C and the subsequent risk of atherosclerotic heart disease.1 2 3 However, despite a great deal of recent progress in understanding the biochemistry and genetics of HDL metabolism, the molecular and cellular mechanisms underlying the apparent antiatherogenic effects of HDL remain unclear.4 The HDLs are heterogeneous, small (70 to 100 Å) lipid-protein particles composed of a core of CE (with a small amount of TG) surrounded by a phospholipid monolayer containing a variety of lipoproteins and UC (Fig 1Down).4 Apo A-I and apo A-II are the major protein components of HDL, constituting {approx}70% and 20%, respectively, of the HDL protein. Some HDL particles contain only apo A-I, whereas others contain both apo A-1 and apo A-II. As described below, recent data suggest that these two classes of HDL particles may differ significantly in their antiatherogenic potential.5 6 HDL particles contain, in addition to apo A-I and apo A-II, smaller amounts of apo A-IV, apo E, apo C, and apo D. HDL can also associate with two important lipid transfer proteins: LCAT, which catalyzes the formation of CE and lysolecithin from UC and lecithin (phosphatidyl choline), and CETP, which promotes the transfer of CEs from HDL to LDL and VLDL in exchange for TG. In addition, HDL particles undergo modification of their core lipid composition after interaction with hepatic lipase.



View larger version (18K):
[in this window]
[in a new window]
  		Figure 1. Schematic of the structure of a mature HDL particle. See text for a detailed description of the structure of HDL. PL indicates phospholipid.

Nascent discoidal HDL particles containing predominantly phospholipid, UC, and apo A-I are secreted de novo from the intestine and liver and arise also in the plasma through the association of apolipoproteins and phospholipids liberated from the surface of TG-rich lipoproteins (VLDL and chylomicrons) after lipolysis4 (Fig 2Down). The maturation of nascent HDL particles involves the uptake of UC from cells in the periphery and from metabolized TG-rich lipoproteins and its conversion to CEs by HDL-associated LCAT. These CEs are then displaced to the core of the HDL particles, resulting in both a significant increase in the size and lipid content and a spherical transformation of the HDL. Human HDL particles sediment as two major peaks, called HDL2 and HDL3, which differ in their contents of both apo A-I and CE.4 The larger HDL2 particles contain significantly more CE and an additional apo A-I molecule compared with the HDL3 particles. The steady-state concentration of HDL thus reflects the complex interactions of synthetic and remodeling events together with catabolism, the latter involving a putative HDL receptor.



View larger version (18K):
[in this window]
[in a new window]
  		Figure 2. Schematic of HDL metabolism. Nascent HDL is secreted de novo from the liver and intestine and is also formed in serum from hepatic and intestinally secreted apolipoproteins and phospholipids and UC derived from the metabolism of TG-rich lipoproteins. UC derived from peripheral tissues is transferred to the surface of nascent HDL, where it is converted to CE by HDL-associated LCAT, resulting in the production of mature HDL. CE from mature HDL is transferred to the liver for metabolism by at least three pathways: (1) CETP-mediated exchange of HDL-derived CE for LDL- or VLDL-derived triglyceride, (2) selective uptake of CE by hepatocytes, and (3) apo E–mediated uptake of HDL by the LDLRs and remnant receptors (RemR).

In 1968, Glomset7 hypothesized that the antiatherogenic properties of HDL could be explained by its ability to promote "reverse cholesterol transport." According to this hypothesis, UC from both peripheral cells and TG-rich lipoproteins is first transferred to the surface of HDL particles, where it is esterified by HDL-associated LCAT and transferred to the hydrophobic core of the HDL particle. Such CEs are then transported to the liver for further metabolism and secretion by at least three pathways: (1) CETP-mediated transfer to LDL followed by LDLR-mediated hepatic uptake, (2) direct apo E–mediated hepatic uptake of HDL via the LDL or remnant receptors, and (3) selective transfer to hepatocytes by an unclear mechanism that does not involve HDL particle uptake8 (Fig 2Up).

During the past 10 years, human genetic studies have provided an important foundation for understanding the role of HDL in regulating cholesterol metabolism and have provided some support for the reverse cholesterol transport model. Several mutations have been described that have important effects on HDL levels and composition in humans. First, many different mutations in the apo A-I gene have been described that alter HDL structure and function.4 9 Most importantly, patients homozygous for deletions or inversions of the apo A-I/apo C-III/apo A-IV gene locus on chromosome 11 lack both apo A-I and plasma HDL and display a reproducible phenotype that includes corneal opacifications, palmar xanthomas, and premature coronary artery disease. Similarly, a frame shift mutation affecting the fifth codon of the apo A-I gene that results in a complete absence of the molecule also results in premature atherosclerosis. Interestingly, however, other less severe deletion and missense mutations affecting more C-terminal portions of the apo A-I protein do not produce an increased risk of atherosclerosis, even though they often result in very low serum HDL levels. Taken together, these findings suggest an important role for apo A-I in determining atherogenic risk, but they raise the possibility that at least some of the antiatherogenic effects of the molecule may be mediated by an HDL-independent mechanism.

As described above, LCAT has been postulated to play an important role in the regulation of both HDL levels and composition. In support of these hypotheses, patients with defects in LCAT activity display two overlapping but distinct phenotypes.10 Those with familial LCAT deficiency display a complete lack of LCAT activity. As a result, they are unable to produce mature HDL2 and HDL3 particles and, instead, accumulate both nascent discoid and small, CE-poor spherical forms of HDL and display low levels of serum HDL-C. Moreover, they have low levels of serum apo A-I, possibly as a result of the abnormally rapid clearance of small HDL particles from the circulation. In addition to abnormalities in HDL metabolism, these patients accumulate large VLDL-like particles and large and intermediate-size LDL2 particles that are rich in UC. Clinically, patients with familial LCAT deficiency display corneal opacifications, a normochromic anemia, and renal insufficiency, the latter probably due to lipid deposition in both the glomeruli and renal arterioles. Perhaps most interestingly, although these patients have low levels of circulating HDL, they do not appear to be at increased risk for coronary artery disease. A second subset of patients with LCAT deficiency, those with so-called "fish eye disease," have mutations in the LCAT gene that selectively prevent it from associating with HDL but leave intact its ability to interact with VLDL and LDL. These patients have markedly reduced HDL levels, with elevated levels of HDL UC similar to patients with familial LCAT deficiency. However, unlike patients with familial LCAT deficiency, patients with fish eye disease do not have increased levels of UC in their LDL and VLDL fractions. Like patients with familial LCAT deficiency, they also do not appear to be at increased risk for atherosclerotic vascular disease.

There are several possible explanations for the paradoxical lack of increased atherosclerotic risk in patients with markedly reduced HDL levels secondary to LCAT deficiencies.10 First, it is possible that in addition to their defects in HDL metabolism, patients with LCAT deficiency also have defective LDL metabolism, which provides a secondary antiatherogenic effect. Alternatively, it is possible that HDL does not directly protect against atherosclerosis and that the inverse correlation between HDL-C levels and atherosclerosis risk reflects secondary lipid abnormalities in patients with low HDL levels. In this regard, it is important to emphasize that isolated HDL deficiency is rare in humans and is more typically associated with elevated levels of plasma TG and the accumulation of small, dense LDL particles, each of which may increase the risk of atherosclerotic vascular disease.4

The limited number of patients with genetic defects of HDL metabolism, combined with the difficulty of human experimentation, has impeded the elucidation of the role of HDL in protection against atherosclerosis. It has been clear for some time that such studies would be greatly facilitated by genetically manipulatable animal models of the dyslipidemias. Until recently, however, such studies have been difficult. For example, the mouse, by far the most convenient and genetically pliable model, is not a good model system for genetic lipid disorders. In mice, HDL, rather than LDL, is the major circulating lipoprotein. In addition, mice lack CETP activity. Most importantly, mice are remarkably resistant to atherosclerosis even after prolonged feeding with a high-fat diet. Fortunately,8 this situation has changed dramatically in the past 10 years with the advent of powerful in vivo gene transfer technologies that have allowed us, for the first time, to manipulate the genotypes and phenotypes of mice in such a way as to make them much more accurate models of human lipid metabolism and atherosclerosis.

The first important advance in this area was the development of transgenic mouse technologies. In such studies, the injection of a single-cell fertilized mouse embryo with an appropriate DNA construct can be used to produce (transgenic) lines of mice that express a foreign gene of interest in specific tissues and that stably transmit this transgene to their offspring. Thus, for example, one can produce mice that express the human CETP gene or that overexpress human or murine LCAT so as to study the roles of these proteins in lipid metabolism. Of equal importance, it is possible to produce double- or triple-transgenic mice that overexpress multiple genes involved in lipid metabolism. A second powerful genetic technique was developed by Cappechi and coworkers,11 who demonstrated that one can use homologous recombination to introduce null (or other) mutations into specific genes in mouse embryonic stem cells and that such mutant alleles can ultimately be passed through the germ line to establish mice homozygous for these mutations. The ability to target or knock out individual genes in the mouse by such homologous recombination approaches has both profoundly increased our understanding of the role of these genes in normal tissue development and function and produced important new mouse models of human disease. Such techniques, for example, have been used to knock out the apo E gene in mice.12 13 The resultant mice have markedly increased levels of serum cholesterol and suffer from premature atherosclerotic vascular disease that histologically resembles its human counterpart. Thus, in addition to elucidating the role of apo E in lipid metabolism, such mice represent a powerful animal model system for studies of the molecular and cellular pathophysiology of human atherosclerosis.

What have we learned from such mouse genetic experiments with regard to HDL metabolism and biology, and how does this information correlate with the results of the clinical studies described above? Mice have now been produced that overexpress human apo A-I,14 human and murine apo A-II,15 16 human CETP,17 human LCAT,18 19 and human apo C-III both alone20 and in combination.21 In addition, mice lacking human apo A-I have been described.22 A full description of these mice is beyond the scope of this editorial, and the reader is referred to several recent reviews of this subject.8 16 23 However, these results have provided us with an extraordinary amount of important and, in some cases, surprising new information, which can be summarized as follows. Transgenic mice expressing the human apo A-I protein in the liver demonstrated humanized HDL profiles composed of HDL2- and HDL3-like particles and were protected against early fatty streak formation induced by an atherogenic diet.14 Thus, consistent with human genetic studies, apo A-I appears to play an important role in determining the structure of HDL and in protecting against atherosclerosis. In marked contrast to the results obtained with the apo A-I mice, mice expressing murine apo A-II displayed increased numbers of fatty streaks even when maintained on a chow diet.16 This result was particularly striking in that the apo A-II mice displayed elevated levels of HDL-C. Therefore, these experiments clearly demonstrated that the composition as well as the absolute level of HDL-C is an important determinant of atherosclerotic risk and showed that apo A-II appears to be proatherogenic. Mice transgenic for apo C-III, which is normally associated with both VLDL and HDL, display an interesting phenotype characterized by isolated hypertriglyceridemia, with TG levels proportional to the levels of apo C-III expression, suggesting that apo C-III plays an important role in setting serum TG levels.20 Mice transgenic for human CETP express only the human protein (because mice do not express endogenous CETP) and display modest reductions in HDL-C consistent with an important role for CETP in transferring HDL CE to LDL and VLDL.17 More interestingly, triple-transgenic mice expressing human CETP, human apo A-I, and human apo C-III display a complex phenotype characterized by low HDL-C, small HDL particle size, and hypertriglyceridemia, thereby mimicking the most common low-HDL phenotype seen in humans, one that is associated with a high risk of coronary artery disease.24 It will be of great interest to determine the susceptibility of these triple-transgenic mice to atherosclerotic vascular disease.

More recently, transgenic mice have also been produced that overexpress human LCAT either alone or in conjunction with its major coactivator, human apo A-I.18 19 Mice overexpressing human LCAT alone demonstrated modest (less than threefold) increases in HDL-C, increased HDL CE, larger HDL particle size, and, most interestingly, an increased accumulation of apo E–rich HDL particles. Mice expressing both human LCAT and human apo A-I displayed fourfold elevations in total cholesterol and twofold elevations in HDL CE levels. Although these results are consistent with an important role for LCAT in determining HDL-C levels and in reverse cholesterol transport, it will be of great interest to cross these mice to atherosclerosis-prone strains, such as the apo E and LDLR knockout mice, to assess the protective effects of LCAT overexpression.

Transgenic mice have a number of unique advantages with regard to genetic studies of lipid metabolism. Such mice are genetically homogeneous and can be crossbred to produce multigenic models of the dyslipidemias. Moreover, because they display stable expression of the transgene, they can be used in long-term studies of the pathophysiology of atherogenesis. Despite these advantages, transgenic mice are extremely expensive to maintain in large numbers, and their relatively slow reproductive rate limits the numbers of combinations that can be generated. Thus, it would clearly be advantageous to develop techniques for in vivo gene transfer that could be rapidly and economically adapted to large numbers of different transgenes and mice. Recently, a number of groups have demonstrated that RDAd vectors can be used to efficiently program recombinant gene expression in a wide range of tissue types in vivo.25 26 27 RDAd vectors display a number of properties that make them ideally suited as vectors for in vivo gene transfer.25 26 27 Adenoviruses are double-stranded DNA viruses that cause self-limited respiratory infections in humans. RDAds in which the E1 genes at the left end of the genome have been replaced with an appropriate transgene and transcriptional regulatory element(s) can be used to efficiently infect most replicating and nonreplicating cell types in vivo, but they lack the ability to regenerate infectious progeny after an initial injection into mice. RDAd can be prepared easily and economically at very high titers. Thus, it is possible to produce a relatively large number of vectors encoding different wild-type and mutant transgenes and to transduce large numbers of cells in vivo with small volumes of these viruses. In particular, it is clear that adenovirus vectors injected intravenously home to the liver and that a single intravenous injection of mice with 1x109 to 5x109 pfu of RDAd results in the selective transduction of 10% to 100% of the hepatocytes in these animals. After infection, the adenovirus genome is maintained as a linear episome, thereby obviating the risk of insertional mutagenesis associated with viruses that integrate into the host chromosome. In addition, RDAds have a favorable safety profile and have not been associated with human malignancies or persistent or latent infections. Compared with the production of transgenic animals, adenoviruses are more convenient and far less expensive to prepare. Moreover, they can be used alone and in combinations to rapidly produce large numbers of animals expressing one or more transgenes. In addition, their use can be easily extended to multiple mouse strains and to other species, including nonhuman primates. Finally, as described below, they may ultimately have potential applications for human gene therapy.

Given these advantages, a number of groups have recently prepared RDAd vectors encoding apolipoproteins and lipid-modifying enzymes and have started to test the efficacy of these vectors in altering lipid profiles and atherogenic risk in mice.28 29 30 31 32 33 The article by Seguret-Mace et al in this issue of Circulation31 represents an elegant combination of transgenic and adenovirus-mediated gene transfer approaches. The authors constructed an RDAd vector encoding human LCAT and injected this vector intravenously into transgenic mice expressing human apo A-I. Plasma HDL-C levels rose sixfold and human apo A-I levels rose more than twofold between 5 and 7 days after adenovirus injection. These elevations were dependent on the dose of adenovirus administered. In addition, HDL particle size increased, and the fatty acid composition of HDL CEs resembled a human profile more closely than the endogenous mouse profile. Perhaps most importantly, the authors demonstrated that serum from the adenovirus-infected animals mediates increased cholesterol efflux from cholesterol-loaded cells in vitro compared with serum from control-infected animals. These results have several important implications both for our understanding of the role of LCAT in HDL metabolism and for the future use of adenovirus vectors as both scientific and therapeutic tools. First, the findings using adenovirus infection generally confirm the previously published results by this group and others concerning LCAT transgenic mice.18 19 This is reassuring, because it demonstrates that adenovirus-mediated gene transfer does not itself artifactually perturb lipid metabolism in these animals and suggests that this technique can be used as a surrogate to transgenesis. Second, the findings that the observed changes in HDL profiles were dose dependent and that it is possible to produce high levels of LCAT expression after adenovirus-mediated gene transfer suggest that it will be possible to easily perform dose-response relationships using adenovirus vectors, a task that is possible but somewhat cumbersome with transgenic animals. The present study also provides important confirmatory evidence regarding the important role of LCAT in reverse cholesterol transport. As such, it suggests that modifications of HDL composition by overexpression of apolipoproteins, lipoprotein receptors, and lipid-modifying enzymes such as LCAT may prove useful as gene therapy approaches to modify atherosclerotic risk. Finally, the study also teaches us something new about LCAT, ie, that LCAT appears to play an important role in determining the serum concentrations of apo A-I, possibly by delaying the catabolism of apo A-I associated with large HDL particles. This result was not seen in the LCAT transgenic animals, perhaps because of the relatively lower levels of LCAT expression in the transgenic compared with the adenovirus-infected animals, and points out the importance of being able to reproducibly modify the levels of transgene expression.

As is true of all important early studies, the work of Seguret-Mace and colleagues is perhaps most exciting in terms of its future potential. Ultimately, of course, we would like to use adenovirus-mediated gene transfer of both wild-type and mutant LCAT to ask directly about the role of this molecule (and others) in modifying atherogenic risk in animals. Moreover, such vectors have obvious potential as therapeutic tools in humans with dyslipidemias. To accomplish these goals, however, it will be necessary to produce long-term (months to years) gene expression after intravenous injection of RDAd. Obtaining such long-term gene expression has proved to be the "Achilles' heel" of the adenovirus vector system. Thus, until very recently, infection of immunocompetent mice with first-generation RDAd encoding human proteins has resulted only in transient recombinant gene expression lasting <4 weeks.34 35 36 This transient gene expression is due to a complex set of cellular and humoral host immune responses directed against both the adenovirus itself and the foreign (human) transgene products that eliminate the virus-infected cells.37 38 39 40 Moreover, it has proved impossible to readminister the same vector to mice after an initial infection. Recently, however, several groups have reported solutions to these problems in mice. First, intramuscular injection of first-generation RDAd encoding mouse as opposed to human proteins results in long-term gene expression, at least in the case of some transgenes.39 Second, injection of neonatal as opposed to adult animals results in tolerance and long-term gene expression in vivo.38 Third, transient immunosuppression with monoclonal antibodies directed against CD4 or CD40 ligand, and treatment with CTLA4 Ig, a soluble inhibitor of the CD28 T-cell activation pathway, have all been reported to produce long-term gene expression in adult immunocompetent mice and, in some cases, to allow readministration of the vectors.41 42 Finally, modifications of the viral vector itself may help to stabilize gene expression.43 Thus, it is fair to say that we are now ready to use RDAd vectors as long-term probes of in vivo lipid metabolism in mice. The wish list for such experiments is long. With regard to the work of Seguret-Mace et al in this issue of Circulation,31 it will be of great interest to study the long-term effects on atherogenesis of adenovirus-mediated overexpression of LCAT in atherosclerosis-prone strains, such as the apo E and LDLR knockout mice. Of equal importance, it will be of interest to compare the effects of overexpression of wild-type LCAT with those of mutant LCATs that selectively lack the ability to associate with either HDL or VLDL/LDL. More generally, it will be of interest to overexpress specific human alleles of apo E in the apo E knockout mice to study their protective effects with regard to atherogenesis, and one can easily think of at least a dozen other interesting adenoviruses that could be used alone or in combination to affect lipid metabolism in mice.

What about the therapeutic potential of such adenovirus vectors for inherited lipid disorders? Although it is promising, I would argue that there are at least two important hurdles that must be overcome before adenovirus-mediated human gene therapy can be used to treat inherited lipid disorders. First, in many cases we must better understand the basic biology of lipid metabolism in order to rationally design successful gene therapies for many of these disorders. The surprising findings concerning the potentially proatherogenic role of apo A-II underscores this concern. The transgenic and adenovirus experiments described above should be most helpful in this regard, particularly because we now have in hand much more accurate mouse models of the human lipid disorders. Second, it will be important to confirm our ability to safely produce long-term adenovirus-mediated gene expression in humans after either vector (and transgene) modification or transient immunosuppression before human trials with these vectors are initiated. Despite these hurdles, the tremendous progress in this field in the past 3 to 5 years augurs well for our eventual success. The inherited lipid disorders represent excellent and clinically important targets for such human gene therapies.


*    Selected Abbreviations and Acronyms
 
apo = apolipoprotein
CE = cholesteryl ester
CETP = cholesteryl ester transfer protein
HDL-C = HDL cholesterol
LCAT = lecithin-cholesterol acyltransferase
LDLR = LDL receptor
RDAd = replication-defective adenovirus
UC = free (unesterified) cholesterol


*    Acknowledgments
 
I would like to thank Drs M. Parmacek and N. Davidson for critical review of the manuscript. L. Gottschalk provided assistance with the preparation of illustrations, and P. Lawrey helped with the preparation of the manuscript. This work was supported in part by NIH grants DK-48987 and HL-54592 to Dr Leiden.


*    Footnotes
 
The opinions expressed in this editorial are not necessarily those of the editors or of the American Heart Association.


*    References
up arrowTop
 up arrowIntroduction
 *References
 

  1. Miller NE. Associations of high-density lipoprotein subclasses and apolipoproteins with ischemic heart disease and coronary atherosclerosis. Am Heart J. 1987;113:589-597.[Medline] [Order article via Infotrieve]
  2. Castelli WP, Garrison RJ, Wilson PW, Abbott RF, Kalousdian S, Kannel WB. Incidence of coronary heart disease and lipoprotein cholesterol levels: the Framingham study. JAMA. 1986;256:2835-2838.[Abstract]
  3. Gordon DJ, Knoke J, Probstfield JL, Superko R, Tyroler HA. High-density lipoprotein cholesterol and coronary heart disease in hypercholesterolemic men: the Lipid Research Clinics Coronary Primary Prevention Trial. Circulation. 1986;74:1217-1225.[Abstract/Free Full Text]
  4. Breslow JL. Familial disorders of high-density lipoprotein metabolism. In: Scriver CR, Beaudet AL, Sly WS, Valle D, eds. The Metabolic and Molecular Bases of Inherited Disease. 7th ed. New York, NY: McGraw-Hill Inc; 1995;11:2031-2052.
  5. Castro GR, Fielding CJ. Early incorporation of cell-derived cholesterol into pre-beta-migrating high-density lipoprotein. Biochemistry. 1988;27:25-29.[Medline] [Order article via Infotrieve]
  6. Hughes TA, Moore MA, Joyce M, Go RC, Segrest JP, Blackwell T. Sexual differences in lipoprotein composition in a family with dyslipidemic hypertension with premature atherosclerosis: deficiency of high-density lipoprotein-L and high-density lipoprotein-M "apolipoprotein-I alone" particle. J Lab Clin Med. 1992;119:57-58.[Medline] [Order article via Infotrieve]
  7. Glomset JA. The plasma lecithin: cholesterol acyltransferase reaction. J Lipid Res. 1968;9:155-167.[Abstract]
  8. Knecht TP, Glass CK. The influence of molecular biology on our understanding of lipoprotein metabolism and the pathobiology of atherosclerosis. Adv Genet. 1995;32:141-198.[Medline] [Order article via Infotrieve]
  9. Assmann G, von Eckardstein A, Funke H. High density lipoproteins, reverse transport of cholesterol and coronary artery disease: insights from mutations. Circulation. 1993;87(suppl III):III-28-III-34. Review.
  10. Glomset JA, Assmann G, Gjone E, Norum KR. Lecithin: cholesterol acyltransferase deficiency and fish eye disease. In: Scriver CR, Beaudet AL, Sly WS, Valle D, eds. The Metabolic and Molecular Bases of Inherited Disease. 7th ed. New York, NY: McGraw-Hill Inc; 1995;11:1933-1951.
  11. Capecchi MR. Targeted gene replacement. Sci Am. 1994;270:52-59. Review.[Medline] [Order article via Infotrieve]
  12. Zhang SH, Reddick RL, Piedrahita JA, Maeda N. Spontaneous hypercholesterolemia and arterial lesions in mice lacking apolipoprotein E. Science. 1992;258:468-471.[Abstract/Free Full Text]
  13. Plump AS, Smith JD, Hayek T, Aalto-Setala K, Walsh A, Verstuyft JG, Rubin EM, Breslow JL. Severe hypercholesterolemia and atherosclerosis in apolipoprotein E-deficient mice created by homologous recombination in ES cells. Cell. 1992;71:343-353.[Medline] [Order article via Infotrieve]
  14. Rubin EM, Krauss RM, Spangler EA, Verstuyft JG, Clift SM. Inhibition of early atherogenesis in transgenic mice by human apolipoprotein AI. Nature. 1991;353:265-267.[Medline] [Order article via Infotrieve]
  15. Warden CH, Hedrick CC, Qiao J-H, Castellani LW, Lusis AJ. Atherosclerosis in transgenic mice overexpressing apolipoprotein A-II. Science. 1993;261:469-472.[Abstract/Free Full Text]
  16. Schultz JR, Gong EL, McCall MR, Nichols AV, Clift SM, Rubin EM. Expression of human apolipoprotein A-II and its effect on high density lipoproteins in transgenic mice. J Biol Chem. 1992;267:21630-21636.[Abstract/Free Full Text]
  17. Agellon LB, Walsh A, Hayek T, Moulin P, Jiang XC, Shelanski SA, Breslow JL, Tall AR. Reduced high density lipoprotein cholesterol in human cholesteryl ester transfer protein transgenic mice. J Biol Chem. 1991;266:10796-10801.[Abstract/Free Full Text]
  18. Francone OL, Gong EL, Ng DS, Fielding CJ, Rubin EM. Expression of human lecithin-cholesterol acyltransferase in transgenic mice. J Clin Invest. 1995;96:1440-1448.
  19. Vaisman BL, Klein H-G, Rouis M, Berard AM, Kindt MR, Talley GD, Meyn SM, Hoyt RE, Marcocina S, Albers JJ, Hoeg JM, Brewer HB, Santamarina-Fojo S. Overexpression of human lecithin cholesterol acyltransferase leads to hyperalphalipoproteinemia in transgenic mice. J Biol Chem. 1995;270:12269-12275.[Abstract/Free Full Text]
  20. Ito Y, Azrolan N, O'Connell A, Walsh A, Breslow JL. Hypertriglyceridemia as a result of human apo CIII gene expression in transgenic mice. Science. 1990;249:790-793.[Abstract/Free Full Text]
  21. Hayek T, Azrolan N, Verdery RB, Walsh A, Chajek-Shaul T, Agellon LB, Tall AR, Breslow JL. Hypertriglyceridemia and cholesterol ester transfer protein interact to dramatically alter high density lipoprotein levels, particle sizes, and metabolism. J Clin Invest. 1993;92:1143-1152.
  22. Li H, Reddick RL, Maeda N. Lack of apo A-1 is not associated with increased susceptibility to atherosclerosis in mice. Arterioscler Thromb. 1993;13:1814-1821.[Abstract/Free Full Text]
  23. Breslow JL. Transgenic mouse models of lipoprotein metabolism and atherosclerosis. Proc Natl Acad Sci U S A. 1993;90:8314-8318.[Abstract/Free Full Text]
  24. Hayek T, Ito Y, Azrolan N, Verdery RB, Aalto-Setala K, Walsh A, Breslow JL. Dietary fat increases high density lipoprotein (HDL) levels both by increasing the transport rates and decreasing the fractional catabolic rates of HDL cholesterol ester and apolipoprotein (apo) A-I: presentation of a new animal model and mechanistic studies in human apo A-I transgenic and control mice. J Clin Invest. 1993;91:1665-1671.
  25. Kozarsky KF, Wilson JM. Gene therapy: adenovirus vectors. Curr Opin Genet Dev. 1993;3:499-503.[Medline] [Order article via Infotrieve]
  26. Kremer EJ, Perricaudet M. Adenovirus and adeno-associated virus mediated gene transfer. Br Med Bull. 1995;51:31-44.[Abstract/Free Full Text]
  27. Brody SL, Crystal RG. Adenovirus-mediated in vivo gene transfer. Ann N Y Acad Sci. 1994;716:90-101.[Abstract]
  28. Ishibashi S, Brown MS, Goldstein JL, Gerard RD, Hammer RE, Herz J. Hypercholesterolemia in low density lipoprotein receptor knockout mice and its reversal by adenovirus-mediated gene delivery. J Clin Invest. 1993;92:883-893.
  29. Stevenson SC, Marshall-Neff J, Teng B, Lee CB, Roy S, McClelland A. Phenotypic correction of hypercholesterolemia in apoE-deficient mice by adenovirus-mediated in vivo gene transfer. Arterioscler Thromb Vasc Biol. 1995;15:479-484.[Abstract/Free Full Text]
  30. Kashyap V, Santamarina-Fojo S, Brown DR, Parrott CL, Applebaum-Bowden D, Meyn S, Talley G, Paigen B, Maeda N, Brewer HB. Apolipoprotein E deficiency in mice: gene replacement and prevention of atherosclerosis using adenovirus vectors. J Clin Invest. 1995;96:1612-1620.
  31. Seguret-Mace S, Latta-Mahieu M, Castro G, Luc G, Fruchart J-C, Rubin E, Denefle P, Duverger N. Potential gene therapy for lecithin-cholesterol acyltransferase (LCAT)–deficient and hypoalphalipoproteinemic patients with adenovirus-mediated transfer of human LCAT gene. Circulation. 1996;94:2177-2184.[Abstract/Free Full Text]
  32. Kozarsky KF, Mckinley DR, Austin LL, Raper SE, Stratford-Perricaudet LD, Wilson JM. In vivo correction of low density lipoprotein receptor deficiency in the Watanabe heritable hyperlipidemic rabbit with recombinant adenoviruses. J Biol Chem. 1994;269:13695-13702.[Abstract/Free Full Text]
  33. Kozarsky KF, Jooss K, Donahee M, Strauss JF, Wilson JM. Effective treatment of familial hypercholesterolaemia in the mouse model using adenovirus-mediated transfer of the VLDL receptor gene. Nat Genet. 1996;13:54-62.[Medline] [Order article via Infotrieve]
  34. Dai Y, Schwarz EM, Gu D, Zhang WW, Sarvetnick N, Verma IM. Cellular and humoral immune responses to adenoviral vectors containing factor IX gene: tolerization of factor IX and vector antigens allows for long-term expression. Proc Natl Acad Sci U S A. 1995;92:1401-1405.[Abstract/Free Full Text]
  35. Barr E, Carroll J, Kalynych AM, Tripathy SK, Kozarsky K, Wilson JM, Leiden JM. Percutaneous transluminal gene transfer into the heart using replication-defective recombinant adenovirus. Gene Ther. 1994;1:51-58.[Medline] [Order article via Infotrieve]
  36. Smith TA, Mehaffey MG, Kayda DB, Saunders JM, Yei S, Trapnell BC, McClelland A, Kaleko M. Adenovirus mediated expression of therapeutic plasma levels of human factor IX in mice. Nat Genet. 1993;5:397-402.[Medline] [Order article via Infotrieve]
  37. Yang Y, Li Q, Ertl HC, Wilson JM. Cellular immunity to viral antigens limits E1-deleted adenoviruses for gene therapy. Proc Natl Acad Sci U S A. 1994;91:4407-4411.[Abstract/Free Full Text]
  38. Tripathy SK, Goldwasser E, Lu MM, Barr E, Leiden JM. Stable delivery of physiologic levels of recombinant erythropoietin to the systemic circulation by intramuscular injection of replication-defective adenovirus. Proc Natl Acad Sci U S A. 1994;91:11557-11561.[Abstract/Free Full Text]
  39. Tripathy SK, Black HB, Goldwasser E, Leiden JM. Immune responses to transgene-encoded proteins limit the stability of gene expression after injection of replication-defective adenovirus vectors. Nat Med. 1996;2:545-550.[Medline] [Order article via Infotrieve]
  40. Yang Y, Li Q, Ertl HC, Wilson JM. Cellular and humoral immune responses to viral antigens create barriers to lung-directed gene therapy with recombinant adenoviruses. J Virol. 1995;69:2004-2015.[Abstract]
  41. DeMatteo RP, Markmann JF, Kozarsky KF, Barker CF, Raper SE. Prolongation of adenoviral transgene expression in mouse liver by T lymphocyte subset depletion. Gene Ther. 1996;3:4-12.[Medline] [Order article via Infotrieve]
  42. Kay M. Long-term hepatic adenovirus-mediated gene expression in mice following CTLA4lg administration. Nat Genet. 1995;11:191-196.[Medline] [Order article via Infotrieve]
  43. Engelhardt JF, Litzky L, Wilson JM. Ablation of E2A in recombinant adenoviruses improves transgene persistence and decreases inflammatory response in mouse liver. Proc Natl Acad Sci U S A. 1994;91:6196-6200.[Abstract/Free Full Text]



This article has been cited by other articles:


Home page
 CirculationHome page
P. Benoit, F. Emmanuel, J. M. Caillaud, L. Bassinet, G. Castro, P. Gallix, J. C. Fruchart, D. Branellec, P. Denefle, and N. Duverger
Somatic Gene Transfer of Human ApoA-I Inhibits Atherosclerosis Progression in Mouse Models
Circulation, January 12, 1999; 99(1): 105 - 110.
[Abstract] [Full Text] [PDF]

Home page
 Cardiovasc ResHome page
R. D Gerard and D. Collen
Adenovirus gene therapy for hypercholesterolemia, thrombosis and restenosis
Cardiovasc Res, September 1, 1997; 35(3): 451 - 458.
[Full Text] [PDF]

This Article
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Leiden, J. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Leiden, J. M.

Circulation Home | Subscriptions | Archives | Feedback | Authors | Help | AHA Journals Home | Search
Copyright © 1996 American Heart Association, Inc. All rights reserved. Unauthorized use prohibited.