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Abstract
Atherosclerosis is a chronic inflammatory vascular disease and the predominant cause of heart attack and ischemic stroke. Despite the well-known sexual dimorphism in the incidence and complications of atherosclerosis, there are relatively limited data in the clinical and preclinical literature to rigorously address mechanisms underlying sex as a biological variable in atherosclerosis. In multiple histological and imaging studies, overall plaque burden and markers of inflammation appear to be greater in men than women and are predictive of cardiovascular events. However, while younger women are relatively protected from cardiovascular disease, by the seventh decade, the incidence of myocardial infarction in women ultimately surpasses that of men, suggesting an interaction between sex and age. Most preclinical studies in animal atherosclerosis models do not examine both sexes, and even in those that do, well-powered direct statistical comparisons for sex as an independent variable remain rare. This article reviews the available data. Overall, male animals appear to have more inflamed yet smaller plaques compared to female animals. Plaque inflammation is often used as a surrogate end point for plaque vulnerability in animals. The available data support the notion that rather than plaque size, plaque inflammation may be more relevant in assessing sex-specific mechanisms since the findings correlate with the sex difference in ischemic events and mortality and thus may be more reflective of the human condition. Overall, the number of preclinical studies directly comparing plaque inflammation between the sexes is extremely limited relative to the vast literature exploring atherosclerosis mechanisms. Failure to include both sexes and to address age in mechanistic atherosclerosis studies are missed opportunities to uncover underlying sex-specific mechanisms. Understanding the mechanisms driving sex as a biological variable in atherosclerotic disease is critical to future precision medicine strategies to mitigate what is still the leading cause of death of men and women worldwide.
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Affiliation(s)
- Joshua J Man
- From the Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (J.J.M., I.Z.J.).,Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA (J.J.M.)
| | - Joshua A Beckman
- Cardiovascular Division, Vanderbilt University Medical Center, Nashville, TN (J.A.B.)
| | - Iris Z Jaffe
- From the Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (J.J.M., I.Z.J.)
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Shiomi M. The History of the WHHL Rabbit, an Animal Model of Familial Hypercholesterolemia (I) - Contribution to the Elucidation of the Pathophysiology of Human Hypercholesterolemia and Coronary Heart Disease. J Atheroscler Thromb 2019; 27:105-118. [PMID: 31748469 PMCID: PMC7049476 DOI: 10.5551/jat.rv17038-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Animal models that closely resemble both human disease findings and their onset mechanism have contributed to the advancement of biomedical science. The Watanabe heritable hyperlipidemic (WHHL) rabbit and its advanced strains (the coronary atherosclerosis-prone and the myocardial infarction-prone WHHL rabbits) developed at Kobe University (Kobe, Japan), an animal model of human familial hypercholesterolemia, have greatly contributed to the elucidation of the pathophysiology of human lipoprotein metabolism, hypercholesterolemia, atherosclerosis, and coronary heart disease, as described below. 1) The main part of human lipoprotein metabolism has been elucidated, and the low-density lipoprotein (LDL) receptor pathway hypothesis derived from studies using fibroblasts was proven in vivo. 2) Oxidized LDL accumulates in the arterial wall, monocyte adhesion molecules are expressed on arterial endothelial cells, and monocyte-derived macrophages infiltrate the arterial intima, resulting in the formation and progression of atherosclerosis. 3) Coronary lesions differ from aortic lesions in lesion composition. 4) Factors involved in the development of atherosclerosis differ between the coronary arteries and aorta. 5) The rupture of coronary lesions requires secondary mechanical forces, such as spasm, in addition to vulnerable plaques. 6) Specific lipid molecules in the blood have been identified as markers of the progression of coronary lesions. At the end of the breeding of the WHHL rabbit family at Kobe University, this review summarizes the history of the development of the WHHL rabbit family and their contribution to biomedical science.
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Affiliation(s)
- Masashi Shiomi
- Institute for Experimental Animals, Kobe University Graduate School of Medicine
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Nakagawa T, Kikumori A, Kimura N, Shiomi M. Distribution of atherosclerotic lesions in various arteries of WHHLMI rabbits, an animal model of familial hypercholesterolemia. Exp Anim 2019; 68:293-300. [PMID: 30828028 PMCID: PMC6699983 DOI: 10.1538/expanim.18-0175] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
In WHHLMI rabbits, arterial lesions develop spontaneously in various arteries even with
standard chow. Here, we examined the development of arterial lesions in various arteries
to demonstrate standard characteristics of arterial lesions in WHHLMI rabbits. For WHHLMI
rabbits at 6, 12, 20, and 30 months of age, lesion areas and areas of arterial lumen
surfaces were measured using image analysis software. Histopathological sections of
arterial lesions were stained with elastic van Gieson staining. Arterial lesions developed
around bifurcations and expanded with aging. In the aorta, atheromatous lesions were
severe in the thoracic aorta but were mild in the distal part of the abdominal aorta.
Carotid artery lesions progressed in the proximal region and at bifurcations, and the
histopathological features were similar to those of coronary lesions. Pulmonary artery
lesions contained many foam cells. Fibrous lesions were observed in the proximal and
distal areas of the renal arteries, at the bifurcation of the iliac-femoral artery and
mesenteric artery, and around the anastomosis of vertebral arteries. Lesions in the celiac
artery contained foam cells and/or lipid droplets within fibrous lesions. In a pair of
right and left arteries, the arterial lesions tended to progress more in the right artery.
Gender did not affect analysis of arterial lesions. In conclusion, the arterial lesions
expanded from bifurcations, and the morphological features of the arterial lesions varied
depending on the type of artery. These results serve as reference data for arterial
lesions in studies using WHHLMI rabbits.
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Affiliation(s)
- Takayuki Nakagawa
- Division of Comparative Pathophysiology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017, Japan.,Present address: Central Research Laboratories, Nichinichi Pharmaceutical Corporation Ltd., 239-1 Tominaga, Iga, Mie 518-1417, Japan
| | - Akio Kikumori
- Institute for Experimental Animals, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017, Japan
| | - Norie Kimura
- Division of Comparative Pathophysiology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017, Japan
| | - Masashi Shiomi
- Division of Comparative Pathophysiology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017, Japan.,Institute for Experimental Animals, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017, Japan.,Present address: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017, Japan.,Present address: Division of Biological Resources and Development, Analytical Research Center for Experimental Sciences, Saga University, 5-1-1 Nabeshima, Saga 849-8501, Japan
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Identification of novel serum markers for the progression of coronary atherosclerosis in WHHLMI rabbits, an animal model of familial hypercholesterolemia. Atherosclerosis 2019; 284:18-23. [PMID: 30870703 DOI: 10.1016/j.atherosclerosis.2019.02.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 02/21/2019] [Accepted: 02/22/2019] [Indexed: 12/30/2022]
Abstract
BACKGROUND AND AIMS The development of serum markers specific for coronary lesions is important to prevent coronary events. However, analyses of serum markers in humans are affected by environmental factors and non-target diseases. Using an appropriate model animal can reduce these effects. To identify specific markers for coronary atherosclerosis, we comprehensively analyzed the serum of WHHLMI rabbits, which spontaneously develop coronary atherosclerosis. METHODS Female WHHLMI rabbits were fed standard chow. Serum and plasma were collected under fasting at intervals of 4 months from 4 months old, and a total of 313 lipid molecules, 59 metabolites, lipoprotein lipid levels, and various plasma biochemical parameters were analyzed. The severity of coronary lesions was evaluated with cross-sectional narrowing (CSN) corrected with a frequency of 75%-89% CSN and CSN> 90%. RESULTS There was a large variation in the severity of coronary lesions in WHHLMI rabbits despite almost no differences in plasma biochemical parameters and aortic lesion area between rabbits with severe and mild coronary lesions. The metabolites and lipid molecules selected as serum markers for coronary atherosclerosis were lysophosphatidylcholine (LPC) 22:4 and diacylglycerol 18:0-18:0 at 4 months old, LPC 20:4 (sn-2), ceramide d18:1-18:2, citric acid plus isocitric acid, and pyroglutamic acid at 8 months old, and phosphatidylethanolamine plasminogen 16:1p-22:2 at 16 months old. CONCLUSIONS These serum markers were coronary lesion-specific markers independent of cholesterol levels and aortic lesions and may be useful to detect patients who develop cardiovascular disease.
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