Endocrinology Vol. 144, No. 6 2214-2219
Copyright © 2003 by The Endocrine Society
Endochondral Bone Formation in the Heart: A Possible Mechanism of Coronary Calcification
L. A. Fitzpatrick,
R. T. Turner and
E. R. Ritman
Departments of Internal Medicine (L.A.F.), Orthopedics (R.T.T.), and Physiology and Biophysics (E.R.R.), Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905
Address all correspondence and requests for reprints to: Lorraine A. Fitzpatrick, M.D., 5-194 Joseph, Endocrine Research Unit, Mayo Clinic and Mayo Foundation, 200 First Street SW, Rochester, Minnesota 55905. E-mail: fitz{at}mayo.edu.
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Abstract
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During the atherosclerotic process, calcification occurs and is associated with a high likelihood of adverse events. Coronary calcification has been perceived as a passive precipitation of mineral. Recently, calcification associated with atherosclerosis has been found to be the result of an organized, regulated process that is similar to the process of calcification in bone. Mineralization in skeletal tissue can form by endochondral ossification in which mesenchymal cells differentiate into chondroblasts and produce a cartilage matrix which then degenerates and is remodeled to form bone. In this study, hearts from oophorectomized, aged female Sprague Dawley rats were found to contain areas of cartilage. Micro-computerized tomography radiogrammetry provided quantitative images of the architecture and confirmed the calcified tissue. Histological analysis revealed staining for several markers consistent with cartilage and bone tissue: acid phosphatase and bone matrix proteins, osteocalcin, osteopontin, osteonectin, and bone sialoprotein. In addition, cartilage types II, X, and procollagen type I were present.
The presence of chondrocytes in the aged rat heart provides insights into the process of calcification in coronary arteries. Many proteins associated with calcification in bone are present in the cartilage that is present in vascular tissue, suggesting that endochondral calcification is another possible mechanism by which calcification of vascular tissue may occur.
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Introduction
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SKELETAL TISSUE MINERALIZATION occurs by differentiation of specific cells that form a scaffold for either intramembranous or endochondrial ossification. Both of these mechanisms are ordered, highly regulated processes by which specific cells produce certain types of matrix proteins that result in mineralized tissue (1, 2). Intramembranous ossification arises directly from mesenchymal cells that lay down a mat of interlacing fibers composed of collagen and other matrix proteins. This area calcifies and eventually organizes into flat plates of mineralized tissue, and further growth occurs radially by periosteal apposition of new bone. In contrast, with endochondrial ossification, mesenchymal cells differentiate into chondroblasts and produce cartilage matrix. Distinct zones of cartilage form as the cartilaginous skeleton enlarges. The chondrocytes in the primary center of ossification become increasingly hypertrophied and deposit type X collagen, and mineralization begins. The cartilage degenerates and is invaded by vascular endothelial cells creating primary spongiosa that are subsequently remodeled to form bone. Endochondrial bone growth is mediated by several peptide and steroid hormones. Low circulating levels of androgens and estrogens during puberty are associated with increased cell proliferation and rate of collagen maturation. At the end of puberty when sex steroid levels are higher, the growth plates close, and further growth of the skeleton is appositional in nature (2).
Calcium deposition is associated with the atherosclerotic process and with the high likelihood of adverse events such as myocardial infarction and coronary death (3, 4). In the past, coronary calcification was perceived as a passive precipitation of mineral. More recently, evidence suggests that arterial calcification is the result of an organized, regulated process with similarities to osteogenesis (5, 6, 7). For example, in vitro studies have shown that vascular tissue contains cells that can differentiate into osteoblast-like cells (8). These cells spontaneously form mineralized nodules and express important bone morphogenic and matrix proteins (9). These proteins are more abundant in atherosclerotic areas compared with unaffected areas (10). These cells respond to sex steroids, peptide hormones, and growth factors that are responsible for the remodeling process in bone (9, 11, 12, 13). Most of the evidence for the regulated process associated with calcification in coronary arteries has suggested that intramembranous ossification occurs in vascular tissue. In this study, we offer an alternative proposal in an animal model. In this particular model, the process of mineralization is also highly regulated and consists of endochondrial ossification.
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Materials and Methods
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Animal protocols were reviewed and approved by the Mayo Foundation Institutional Animal Care and Use Committee, and animals were maintained and killed according to the guidelines of the National Institutes of Health, United States Department of Agriculture, and Assessment and Accreditation of Laboratory Animal Care (Office of Laboratory Animal Welfare Assurance no. A3291-01). Four ovary-intact (sham) and four oophorectomized (OVX) female Sprague Dawley rats were killed at 23–26 months of age, and the hearts were removed. Ovariectomy or sham surgery was performed at 3 months of age. Hearts were embedded in paraffin for micro-computerized tomography (CT) scanning to visualize the amount of mineralization present. Micro-CT radiogrammetry provides quantitative, high-resolution 3-dimensional images of microarchitecture, with each image consisting of up to 1 billion cubic voxels. The micro-CT images have isotropic resolution, and each cubic voxel is 5 or 25 µm on a side, depending on the scanning condition selected (14). Tomographic reconstructive algorithms are applied to the recorded projection images (15). Mineralization was determined with the micro-CT image, and the amount and extent of coronary calcification was confirmed visually using light microscopy. Paraffin-embedded hearts were cut into 5-µm sections for histological analysis. Sections of the hearts were stained with Goldner’s-Masson-Trichrome and Von Kossa stains that detect mineralization. Immunocytochemistry was performed for bone matrix proteins and collagen using a Vectastain ABC ELITE peroxidase kit (Vector Laboratories, Inc., Burlingame, CA). The bone matrix protein antibodies were the generous gift of Dr. Larry Fisher (National Institute of Dental Research, National Institutes of Health, Bethesda, MD).
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Results
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Hearts from OVX (n = 4) and sham-operated (n = 4) aged rats were scanned by micro-CT. Micro-CT scans allowed spatial resolution of mineralization within the intact rat heart coronary vasculature. In viewing the scans from OVX and sham-operated animals, larger amounts of calcified tissue were found in the hearts from OVX animals. In comparing the sham (n = 4) vs. OVX hearts (n = 4), there was an average increased volume of calcium of approximately 17 mm3 in the OVX hearts. Because calcium accumulates largely in the epicardial coronary arteries with a wall volume of approximately 30 mm3, there would be almost complete replacement of the arterial wall with calcium.
One example of a scanned OVX heart is shown in Fig. 1
. The hydroxyapatite content in this particularly dramatic micro-CT image was 370 mg/cc. When this heart was sectioned, cartilage was found within the vascular tissue. Chondrocytes appear as round, jelly-like cells that contain proteoglycans. This area of cartilage was directly adjacent to the artery adventitia (Fig. 2). Sections from two OVX hearts contained chondrocytes, whereas review of histological sections from four sham-operated hearts failed to reveal any cartilage-like material.
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Figure 1. Maximum intensity projection from a micro-CT scan of a 26-month-old ovariectomized female rat heart. Coronary calcification can be seen in the coronary arteries. On the left is a histological section through a coronary artery. Black staining (Von Kossa stain) is indicative of calcified tissue.
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Figure 2. Cartilage within vascular tissue. Undecalcified section of a heart from a 26-month-old OVX female rat. The microphotograph indicates the presence of cartilage within the vascular tissue. The cartilage is surrounded by blue-green stain (Goldner’s-Masson-Trichrome) depicting hydroxyapatite. The red stain indicates unmineralized matrix. A, The arrow denotes chondrocytes. B and D, High-power magnification of the cartilage. C, Area of the cartilage adjacent to the vessel adventitia.
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Von Kossa staining of the cartilage section indicated that calcification was present (Fig. 3A). This is similar to primary ossification in which the cartilage cells swell through a process of fluid intake, and then the intracellular substance between the swollen cells decreases and becomes calcified. Thus, a thin cap of osseous tissue is laid down in the immediate vicinity of the cartilage. Acid phosphatase staining was present, a marker for osteoclast-like cells (Fig. 3B). This suggests that remodeling could take place and cells capable of differentiating into osteoclasts may be present in the adjacent area.
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Figure 3. Von Kossa and acid phosphatase staining of cartilage within the heart. A, Von Kossa staining in the area of cartilage. The dark staining suggests the initiation of the calcification process and occurs adjacent to the hypertrophic chondrocytes. B, Acid phosphatase staining within the cartilage nidus (arrows).
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Many of the bone matrix proteins were present in the cartilaginous tissue. Diffuse staining was present throughout the cartilage nidus for osteocalcin, a bone matrix protein associated with mineralization (Fig. 4A). Diffuse staining of osteopontin, a calcium-binding lipoprotein common to bone matrix (Fig. 4B), was also present. Osteopontin enhances the binding of osteoclasts to hydroxyapatite through its 
vß3 integrin. In Fig. 4, panels C and D reveal staining for osteonectin and bone sialoprotein, respectively. Bone sialoprotein is a potent stimulator for hydroxyapatite nucleation; hydroxyapatite is the principal mineral in bone. Figure 4E is a negative histologic control section incubated with nonimmune IgG.
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Figure 4. Bone matrix proteins in the rat heart. A, Osteocalcin immunostaining (arrows). Faint, diffuse staining is present throughout the specimen for osteocalcin, a bone matrix protein associated with calcification. B, Osteopontin immunostaining. Diffuse staining of osteopontin is noted throughout the histological specimen (stained pink). Osteopontin is a calcium-binding matrix glycoprotein that facilitates bone resorption by enhancing the binding of the osteoclast to hydroxyapatite. Osteopontin is expressed by smooth muscle derived from cells adjacent to the site of calcification. C, Osteonectin staining. Specific staining for osteonectin, a bone matrix protein found in differentiated osteoblasts, is present in tissue surrounding the cartilage nidus. D, Bone sialoprotein immunostaining in a 26-month-old rat heart. Bone sialoprotein functions as a potent stimulator of hydroxyapatite nucleation. Positive staining (arrows) is present in the nidus of cartilage for bone sialoprotein. E, Negative control histological section incubated with IgG indicating the lack of specific staining.
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Figure 5A is a histological section incubated with IgG to show nonspecific staining. Many types of collagen associated with bone cartilage and formation such as types II, X, and procollagen type I were present within this nidus. Collagen X is specific for cartilage differentiation (Fig. 5B). Figure 5C reveals immunostaining for collagen type II, which was also present in differentiated cartilage tissue. Type I collagen is the predominant collagen in bone; immunostaining for type I procollagen revealed areas of staining and suggests that regions of matrix have structural similarity to bone (Fig. 5D).
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Figure 5. Types II, X, and pro I collagen staining. A, Control histological sections incubated with IgG. No staining is noted. B, Immunostaining for collagen X (arrows), a collagen specific for cartilage differentiation. C, Immunostaining for collagen type II (arrows), a collagen commonly found in differentiated cartilage tissue. Note the staining throughout the cartilage tissue. D, Immunostaining for type I procollagen. A few areas of intense staining are present throughout the specimen and surrounding the nidus of cartilage. Type I collagen is the predominant collagen in bone and reflects a matrix that has potential for calcification.
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Discussion
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The presence of chondrocytes in the aged rat heart provides insights into the process of calcification in coronary arteries. Chondrocytes are derived from mesenchymal cells and are required for endochondrial bone formation. Chondrocytes have been described in cardiovascular tissues in other instances (16). Cartilaginous foci have been described in an aortic valve associated with calcific aortas or in arteries with Mönckeberg’s sclerosis (10), and hyaline cartilage has been recognized in recent human case reports in aortic valve disease (17, 18).
Several hypotheses and/or experimental models are associated with cartilage metaplasia. Overexpression of TGF ß1 in endothelial cells is associated with cartilage metaplasia and apoptosis (19). Other animal models have suggested that specific growth stimulants, such as rotational stress or devitalization of tissue, can induce cartilage growth (20, 21). More interesting is the knockout mouse for a matrix 
-carboxyglutamic acid protein (Gla protein), which exhibits extensive and lethal cartilaginous metaplasia in the tunica media of arteries and has provided information regarding the role of Gla-containing proteins in calcification of the medial layer of arteries (22).
Other knockout mice models have provided evidence for the association between the presence of cartilage and accelerated atherosclerosis. In spontaneous advanced atherosclerotic lesions in mice with a null mutation in the Apo E gene, widespread hyaline and calcified cartilaginous metaplasia were present (23). These findings were confirmed in diabetic male Apo E knockout mice (24) and were prevented by treatment with 17ß-estradiol. The transformation of young mesenchymal-like cells into chondrocytes is an intriguing and plausible method by which cartilage forms and calcifies, forming bone-like substances in the artery wall.
Proteins associated with the cartilage matrix such as cartilage oligomeric matrix protein (thrombospondin) are expressed by human vascular smooth muscle cells (VSMC). Cartilage oligomeric matrix protein plays a role in adhesion and migration of VSMC in the setting of atherosclerosis (25). In culture, VSMC synthesize two types of proteoglycans that are common to articular cartilage. The mRNA encoding chondroitin/dermatan sulfate proteoglycans, designated biglycan and decorin, are present in bovine VSMC, and these proteins regulate cell-specific actions (26). These findings add to the plausibility that cartilage proteins are made by vascular tissue and could develop a cartilage scaffold that is amenable to calcification. In a study published while this manuscript was in review, subsets of VSMC were identified in human calcified arteries that expressed many proteins, genes, and transcription factors associated with osteogenic and chondrogenic phenotypes. Of note, Sox9, a transcription factor that regulates cartilage differentiation, was highly expressed in carotid atherosclerotic lesions (27).
One difficulty with this preliminary study is the small number of animals and the transient nature of the cartilage scaffold. We have scanned hearts from OVX (n = 4) and sham-operated (n = 4) aged animals and find substantially more calcification in the OVX animals. Only two OVX hearts were suitable for histological review, and both contained a nidus of cartilage. Review of four sham-operated hearts failed to review the presence of chondrocytes. We realize that this is a preliminary, albeit intriguing, finding due to potential sectioning complications and the time limitation of the cartilage scaffold.
This study supports the suggestion that calcification in vascular tissue is a regulated, ordered process. There are many features in common with normal bone formation during the calcification process. In the aged rat heart, endochondrial calcification is present with the formation of chondrocytes that express types II, X, and pro-I collagen. Many matrix proteins that are common to bone are also present and include osteocalcin, osteopontin, osteonectin, and bone sialoprotein. Calcification was confirmed histologically with Goldner’s-Masson-Trichrome and Von Kossa staining and by micro-CT. Thus, endochondrial calcification is one process responsible for calcification of coronary tissue in this model.
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Acknowledgments
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We thank Ms. Ruth Kiefer for expert secretarial assistance and Ms. Kris Shogren and Ms. Ming Ruan for outstanding technical assistance.
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Footnotes
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This work was supported, in part, by U.S. Public Health Service Grants NIH EB0030J, AR45233, and K24RR017593-01.
Abbreviations: CT, Computerized tomography; OVX, oophorectomized; VSMC, vascular smooth muscle cell(s).
Received December 19, 2002.
Accepted for publication March 10, 2003.
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References
|
|---|
- Alman B, Fitzpatrick LA, Shore E, Gomberg BR, Khurana JS 2000 Bone structure and function: morphology, embryology and bone biology. In: Khurana JS, Fitzpatrick LA, Alman B, Kattapuram SV, Gill SS, Raj GA, eds. A compendium of skeletal pathology. New York: United Pathologists Press; 1–31
- Minisola S, Fitzpatrick LA 2002 Bone physiology. In: Eugster EA, Pescovitz OH, eds. Developmental endocrinology. Totowa, NJ: Humana Press; 193–216
- Rumberger JA, Simons DB, Fitzpatrick LA, Sheedy PF, Schwartz RS 1995 Coronary artery calcium area by electron-beam computed tomography and coronary atherosclerotic plaque area: a histopathologic correlative study. Circulation 92:2157–2162[Abstract/Free Full Text]
- Sangiorgi G, Rumberger JA, Severson A, Edwards WD, Gregoire J, Fitzpatrick LA, Schwartz RS 1998 Arterial calcification and not lumen stenosis is highly correlated with atherosclerotic plaque burden in humans: a histologic study of 723 coronary artery segments using nondecalcifying methodology. J Am Coll Cardiol 31:126–133[Abstract/Free Full Text]
- Doherty TM, Uzui H, Fitzpatrick LA, Tripathi PV, Dunstan CR, Astora K, Rajavashisth TB 2002 Rationale for the role of osteoclast-like cells in arterial calcification. FASEB J 16:577–582[Abstract/Free Full Text]
- Donley GE, Fitzpatrick LA 1998 Noncollagenous matrix proteins controlling mineralization: possible role in pathologic calcification of vascular tissue. Trends Cardiovasc Med 8:199–206
- Christian RC, Fitzpatrick LA 1999 Vascular calcification. Curr Opin Nephrol Hypertens 8:443–448[CrossRef][Medline]
- Severson AR, Ingram RT, Fitzpatrick LA 1995 Matrix proteins associated with bone calcification are present in human vascular smooth muscle cells grown in vitro. In Vitro Cell Dev Biol 31:853–857
- Watson KE, Bostrom K, Ravindranath R, Lam T, Norton B, Demer LL 1994 TGF-ß 1 and 25-hydroxycholesterol stimulate osteoblast-like vascular cells to calcify. J Clin Invest 93:2106–2113
- Fitzpatrick LA, Severson A, Edwards WD, Ingram RT 1994 Diffuse calcification in human coronary arteries: association of osteopontin with atherosclerosis. J Clin Invest 94:1597–1604
- Miller VM, Sieck G, Prakash Y, Fitzpatrick LA 1998 Vascular effects of sex steroid hormones. In: Fraser IS, eds. Estrogens and progestogens in clinic practice. London: Churchill Livingstone; 215–223
- Moraghan T, Antoniucci DM, Grenert JP, Sieck G, Johnson C, Miller VM, Fitzpatrick LA 1996 Differential response in cell proliferation to ß estradiol in coronary artery vascular smooth muscle cells obtained from mature female versus male animals. Endocrinology 137:5174–5177[Abstract]
- Balica M, Bostrom K, Shin V, Tillisch K, Demer LL 1997 Calcifying subpopulation of bovine aortic smooth muscle cells is responsive to 17 ß-estradiol. Circulation 95:1954–1960[Abstract/Free Full Text]
- Jorgensen SM, Demirkaya O, Ritman EL 1998 Three-dimensional imaging of vasculature and parenchyma in intact rodent organs with x-ray micro-CT. Am J Physiol 275:H1103–H1114
- Ritman EL, Bolander ME, Fitzpatrick LA, Turner RT 1998 Micro-CT imaging of structure-to-function relationship of bone microstructure and associated vascular involvement. Technol Health Care 6:403–412[Medline]
- Doherty TM, Detrano RC, Mautner SL, Mautner GC, Shavelle RM 1999 Coronary calcium: the good, the bad and the uncertain. Am Heart J 137:806–814[CrossRef][Medline]
- Seemayer TA, Thelmo WL, Morin J 1973 Cartilaginous transformation of the aortic valve. Am J Clin Pathol 60:616–620[Medline]
- Groom DA, Starke WR 1990 Cartilaginous metaplasia in calcific aortic valve disease. Am J Clin Pathol 93:809–812[Medline]
- Schulick AH, Taylor AJ, Zuo W, Qiu CB, Dong G, Woodward RN, Agah R, Roberts AB, Virmani R, Dichek DA 1998 Overexpression of transforming growth factor ß 1 in arterial endothelium causes hyperplasia, apoptosis, and cartilaginous metaplasia. Proc Natl Acad Sci USA 95:6983–6988[Abstract/Free Full Text]
- Lehoczky-Mona J, McCandless EL 1964 Ischemic induction of chrondrogenesis in myocardium. Arch Pathol 78:37-42
- Scapinelli R, Little K 1970 Observations on the mechanically induced differentiation of cartilage from fibrous connective tissue. J Pathol 101:85–91[CrossRef][Medline]
- Luo G, Ducy P, McKee MD, Pinero GJ, Loyer E, Behringer RR, Karsenty G 1997 Spontaneous calcification of arteries and cartilage in mice lacking matrix GLA protein. Nature 386:78–81[CrossRef][Medline]
- Qiao JH, Fishbein MC, Demer LL, Lusis AJ 1995 Genetic determination of cartilaginous metaplasia in mouse aorta. Arterioscler Thromb Vasc Biol 15:2265–2272[Abstract/Free Full Text]
- Tse J, Martin-McNaulty B, Halks-Miller M, Kauser K, DelVecchio V, Vergona R, Sullivan ME, Rubanyi GM 1999 Accelerated atherosclerosis and premature calcified cartilaginous metaplasia in the aorta of diabetic male Apo E knockout mice can be prevented by chronic treatment with 17ß-estradiol. Atherosclerosis 144:303–313[CrossRef][Medline]
- Riessen R, Fenchel M, Chen H, Axel DI, Karsch KR, Lawler J 2001 Cartilage oligomeric matrix protein (thrombospondin-5) is expressed by human vascular smooth muscle cells. Arterioscler Thromb Vasc Biol 21:47–54[Abstract/Free Full Text]
- Jarvelainen HT, Kinsella MG, Wight TN, Sandell LJ 1991 Differential expression of small chondroitin/dermatan sulfate proteoglycans, PG-I/biglycan and PG-II/decorin, by vascular smooth muscle and endothelial cells in culture. J Biol Chem 266:23274–23281[Abstract/Free Full Text]
- Tyson KL, Reynolds JL, McNair R, Zhang Q, Weissberg PL, Shanahan CM 2003 Osteo/chondrocytic transcription factors and their target genes exhibit distinct patterns of expression in human arterial calcification. Arterioscler Thromb Vasc Biol 23:489–494[Abstract/Free Full Text]
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Abstract
Introduction
