Secondary Logo

Share this article on:

The role of OPG/RANKL in the pathogenesis of diabetic cardiovascular disease

Forde, Hannaha; Davenport, Colina; Harper, Emmab; Cummins, Philb,c; Smith, Diarmuida,c

Cardiovascular Endocrinology & Metabolism: June 2018 - Volume 7 - Issue 2 - p 28–33
doi: 10.1097/XCE.0000000000000144
Review article

Cardiovascular (CV) disease is the leading cause of mortality in patients with type 2 diabetes mellitus. A major factor in the pathogenesis of CV disease is vascular calcification (VC), which is accelerated in type 2 diabetes mellitus. Calcification of the vessel wall contributes to vascular stiffness and left ventricular hypertrophy whereas intimal calcification may predispose to plaque rupture and CV death. The pathogenesis of VC is complex but appears to be regulated by the osteoprotegerin (OPG)/receptor activator of nuclear factor-κB ligand (RANKL) signaling pathway, which is involved in bone remodeling. Within the bone, OPG prevents RANKL from binding to receptor activator of nuclear factor-κB and inhibiting bone resorption. Outside of the bone, the clinical significance of OPG blocking RANKL is not well understood, but OPG knockout mice that lack OPG develop early and severe VC. This minireview outlines some of the research on OPG/RANKL in the pathogenesis of VC and discusses potential therapies, which may reduce VC and CV burden in humans.

aAcademic Department of Diabetes Beaumont Hospital, Royal College of Surgeons in Ireland

bDepartment of Vascular Biology, Dublin City University

cThe 3U Diabetes Group Ireland, Dublin, Ireland

This minireview was based on a presentation delivered by Doctor Diarmuid Smith to the European Group of Insulin Resistance in Dublin 2017. This presentation referenced the work of Dr Colin Davenport, Dr Hannah Forde, and Dr Emma Harper who have or are completing PhD studies under the supervision of Dr Smith and Professor Phil Cummins.

Correspondence to Diarmuid Smith, MBBCh, BAO, MD, FRCPI, Diabetes Day Centre, Beaumont Hospital, Beaumont Road, Dublin 9, Ireland Tel/fax: +353 1857 2979; e-mail: diarmuidsmith@beaumont.ie

Received November 2, 2017

Accepted November 21, 2017

In the developed world, cardiovascular disease (CVD), including coronary heart disease and stroke, remains the commonest cause of death, and in diabetes, ∼65% of all deaths in patients with type 2 diabetes mellitus (T2DM) occur because of CVD 1. Our research group has been interested in the role of vascular calcification (VC) in the pathogenesis of CVD in diabetes.

As recently as 25 years ago, the widespread view of calcification within the vasculature was of a passive process of calcium deposition in the vessel walls that was essentially benign in terms of its effects on CVD 2. This viewpoint has changed in recent years with the recognition that VC is an active process involving the transformation of certain vascular cells within the vasculature into osteoblastic cells similar to those involved in bone formation 3–6 and is a pathophysiological process that affects multiple aspects of the vascular tree, in particular the intimal and medial aspects of the arterial wall 7,8. VC exerts numerous detrimental effects on the vasculature, contributing to increased arterial stiffness, widened pulse pressure, increased rates of left ventricular hypertrophy, and increased risk of coronary artery dissection after angioplasty 9, and studies have specifically linked VC to cardiac death, as coronary artery calcification (CAC) in coronary artery disease (CAD) has been shown to be significantly associated with mortality 10. Moreover, intimal VC has been claimed to be an independent risk factor for cardiovascular (CV) death 11. As CVD is the major cause of mortality among diabetes patients 12, it is unsurprising that VC is a pathological condition frequently accelerated in subjects with T2DM 13,14.

Despite the recognition of a clear association between VC burden and rates of CV morbidity and mortality, the cellular mechanisms that promote and inhibit VC remain unclear, and clinical interventions aimed at inhibiting or reversing VC have produced, for the most part, disappointing results 15.

The pathogenesis of VC appears to be controlled by the osteoprotegerin (OPG)/receptor activator of nuclear factor-κB ligand (RANKL)/tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) signaling pathway, which is involved in bone remodeling. OPG is a soluble member of the tumor necrosis receptor superfamily, which exerts its biological functions by acting as a decoy receptor for either RANKL or TRAIL. Within the skeletal system, the interaction and clinical relevance of OPG and RANKL are well-described. In essence, OPG prevents RANKL from binding to the receptor activator of nuclear factor-κB receptor on osteoclast precursor cells, thereby preventing the maturation of osteoclasts, with the result being a net gain in bone mineral density 16. Outside the skeletal system, the clinical significance of OPG blocking RANKL and/or TRAIL signaling is not well understood, but OPG knockout mice that lack OPG develop early and severe VC 17. OPG has been identified as existing within the vasculature in significant amounts, and a study by Morony et al. 18 reported that the administration of OPG to atherogenic mice led to a reduction in calcification burden, whereas in a separate study, the coadministration of OPG with vitamin D prevented VC in mice 19.

RANKL, however, actively promotes the calcification process in vascular cells through an ability to act as an inducer of osteoblastic activity 20. RANKL, when secreted by ECs, can bind to the receptor activator of nuclear factor-κB receptor to promote pathological differentiation of healthy VSMCs into calcified VSMCs with an osteoblastic phenotype 21. In this respect, RANKL is upregulated in calcified VSMCs 22 and has been shown to exert its procalcification actions through activation of the NF-κB pathway 20. Thus, when serum RANKL levels are high, an acceleration of this differentiation process occurs, resulting in an increased mineral deposition within the medial arterial wall 21. Likewise, OPG, which is also expressed in the vasculature by ECs and SMCs, acts as a soluble decoy receptor for RANKL. OPG can bind to and neutralize RANKL to ameliorate the VC process 23, thereby exerting an anticalcific effect within the vasculature (Fig. 1). To further support the proposed OPG/RANKL relationship, isolated murine OPG−/−ApoE−/− VSMCs developed increased calcification and exerted an upregulation of osteochondrogenic genes following RANKL treatment, whereas OPG+/+ApoE−/− VSMCs exhibited no such response. This basic model highlights the protective effect of OPG on VC through the modulation of RANKLs procalcific effects 26.Thus, both RANKL and OPG appear to exert the ‘opposite’ effects during VC to those typically exerted by either of these ligands during bone remodeling 27, an apparent pathophysiological ‘paradox’. A third regulatory protein, TRAIL, has been shown to putatively interact with OPG and RANKL during modulation of the VC process 28, and an emerging hypothesis within the VC field has proposed a vasoprotective role for TRAIL, possibly through pleiotropic effects on vascular gene expression and/or an ability to mediate RANKL signaling. Systemic delivery (both single/repeated injection) of recombinant TRAIL to ApoE-null diabetic mice demonstrated antiatherosclerotic activity 29, and it has been reported that TRAIL has the ability to counteract RANKL’s procalcific signals in both cell culture 30 and murine models 31. A further discussion on TRAIL is beyond the remit of this article, but I would refer readers to a recent review article on TRAIL 32. In contrast to these observations however, it has also been claimed that neither OPG, RANKL, nor TRAIL has any effect on VSMC calcification in vitro 23 and that RANKL has no direct effect on VSMCs 33. The discrepancy in results is likely because of the methodological differences in studies, with some studies using phosphate-containing procalcific growth media, which can enhance calcification, and phosphate itself, which can induce osteoblastic activity. Furthermore, endogenous OPG secretion, primarily by VSMCs 33, leading to RANKL neutralization, is often overlooked, whereas static VSMC monocultures lack endothelial paracrine signaling inputs and shear-mediated conditioning effects that are undoubtedly present in the corresponding in-vivo environment 34,35.

Fig. 1

Fig. 1

In clinical studies, high levels of plasma OPG have been shown to positively predict CVD morbidity and mortality 36, whereas circulating OPG is increased in patient groups with high levels of arterial calcification 37. In the Dallas Heart Study, it was observed that CAC and aortic plaque volume was positively associated with circulating OPG in an unselected population, thereby indicating its possible use as a biomarker for atherosclerosis 38. Moreover, high levels of OPG have been positively correlated with CAD 39 and peripheral vascular disease 40, whereas Omland et al. 41 have highlighted its potential use as a predictor of heart failure and long-term mortality in patients who experience acute coronary syndromes. Higgins et al. 42 have demonstrated that both tissue and serum OPG are strongly and inversely associated with calcification in human carotid atherosclerosis. Elevated serum OPG has also been linked to T2DM. In murine models for example, it has been shown that OPG levels increase shortly after induction of diabetes 29, with a similar trend noted in clinical studies. Many studies have significantly correlated serum OPG elevation with worsening CV burden in T2DM, including CAC 43, carotid intimal–medial thickness 44, hypertension 45 coronary/peripheral arterial disease 46, metabolic syndrome, and microvascular complications 47. Elevated OPG has also been shown to invariably predict coronary artery VC progression in diabetics, and furthermore can be used to predict future CV events 48. Finally, a 2012 study into advanced carotid atherosclerosis illustrated that a history of diabetes and CAD could independently predict circulatory plasma OPG levels 49. Therefore, it is likely that serum OPG concentration may constitute an important and specific CVD biomarker in T2DM. The use of serum RANKL as a CV biomarker is more controversial. It has been claimed for example that circulating RANKL levels exhibit no correlation with either advanced carotid atherosclerosis 49 or carotid intimal–medial thickness 44. More recently however, both serum and tissue RANKL have been positively correlated with carotid calcification in atherosclerotic lesions 42. With respect to T2DM, Gaudio et al. 44 have reported that circulating RANKL levels were lower in diabetics than in control subjects, whereas O’Sullivan et al. 37 reported no change in plasma RANKL levels in T2DM. It has also been reported that RANKL expression is upregulated and localized to areas displaying medial arterial calcification in patients with charcot neuroarthropathy 21, whereas soluble RANKL has also been positively coassociated with well-known biomarkers of heart failure 50. Interestingly, although it may not have intrinsic diagnostic value, Mohammadpour et al. 51 have proposed the OPG: RANKL serum concentration ratio as a biomarker for CAD. In their ischemic coronary disease study cohort, they noted a significant correlation between OPG/RANKL and CAC 51. Overall however, based on recent clinical data, a definitive role for RANKL as a serum biomarker forT2DM/CVD remains inconclusive.

Back to Top | Article Outline

Therapeutic considerations

The dynamic nature of VC offers significant potential for clinical intervention in patients with type 2 diabetes manifesting CV complications. It is clear that the dynamic osteoblastic pathways involving OPG, RANKL, and TRAIL represent ideal therapeutic targets for interference of the calcification process, but to date no treatment options are available for VC across the T2DM/CVD patient spectrum.

Back to Top | Article Outline

Recombinant osteoprotegerin therapy

Unsurprisingly, in view of its mechanism of action, OPG administration has been suggested as one potential treatment option for VC 52. In mice, studies have shown that recombinant OPG fusion protein (Fc-OPG) can inhibit VC 18. In this study, ldlr−/− mice were fed an atherogenic diet alongside Fc-OPG administration; calcification was specifically inhibited with no effect on atherosclerotic lesion number or size.

Back to Top | Article Outline

Antireceptor activator of nuclear factor-κB ligand therapy

Owing to the cross-over in molecular mechanisms between bone morphogenesis and VC, it is possible that a second prospective treatment for VC could be adapted from currently existing osteoporosis therapy 52. Osteoporosis is a systemic skeletal disease in which the level of bone resorption is greater than that of bone formation, leading to continuous bone degradation and ultimately resulting in low bone mass and fragility 53. Denosumab, a human monoclonal antibody for RANKL, is used as a 6 monthly injection to treat osteoporosis and reduce fracture risk 52, although its effects on VC have not yet been fully assessed. Mimicking the natural actions of OPG, denosumab binds and neutralizes RANKL (but not TRAIL), attenuating its osteoclastic effects and allowing osteoblastic buildup of bone to ensue 54. As RANKL promotes osteoblastic activity in VSMCs, anti-RANKL therapy could theoretically function to reduce the extent of calcification in the vasculature. In support of this theory, it has been demonstrated that denosumab reduced aortic calcium levels by half in a mouse model of osteoporosis 55, but contrastingly, the only corresponding human study completed to date has noted no influence of this therapy on aortic calcification progression over a 3 year-period 56. It is possible that this disparity is owing to inconsistencies in calcification measurement, as Samelson et al. 56 utilized a semiquantitative method (lateral spine radiographs) as opposed to the quantitative measurement of aortic calcium deposition employed by Helas et al. 55. Furthermore, this study was a subanalysis of a larger trial initially completed to assess the effects of OPG administration on bone mineral density in osteoporotic postmenopausal women (2363 of 7808 patients). The therapeutic potential of anti-RANKL therapy for the treatment of VC therefore awaits further clinical investigation.

Back to Top | Article Outline

Tumor necrosis factor-related apoptosis-inducing ligand administration

Recombinant TRAIL administration to ApoE-deficient diabetic mice has been shown to significantly reduce atherosclerosis progression 29, whereas TRAIL delivery protects against diabetic vascular injury in rats 57. Also of relevance, TRAIL deficiency appears to promote VC and diabetes in vivo 58. Although these investigations appear promising, more robust human clinical studies are required to determine if TRAIL treatment directly contributes to an improved outcome in patients with CV complications.

Back to Top | Article Outline

Additional therapeutic possibilities

Bisphosphonates (pyrophosphate analogs) are a successful osteoporosis treatment and have been considered as a potential VC therapy option owing to their inhibitory effect on hydroxyapatite crystal formation 59. Although animal studies have shown promise 60, human studies involving bisphosphonates and calcification have revealed mixed results 61,62. Additionally, teriparatide, a shortened recombinant human parathyroid hormone also employed for osteoporosis treatment through its effect on stimulating bone formation, has been shown to reduce VC in ldlr−/− mice 63, but to our knowledge, there are no human data in relation to teriparatide and vascular disease. Statins, which have been routinely employed to lower blood cholesterol and prevent vascular complications associated with CVD and T2DM, have also been considered as a potential treatment option for VC, in view of their inherent pleiotropic properties 52. In this respect, studies thus far have demonstrated conflicting results. Statin-treated patients were shown to reduce aortic stenosis 64, and to have a protective effect on VC in rats 65. Additionally, statins have been shown to reduce levels of procalcific serum RANKL 66 and to increase anticalcific serum OPG. Elsewhere, it has been claimed that statins do not affect aortic stenosis with calcification 67, whereas a recent study has suggested that statins actually promote coronary atheroma calcification 68. Further investigation is clearly warranted therefore to resolve this ongoing debate and determine if the pleiotropic effects of statins can successfully reduce VC. Glucagon like peptide-1 receptor agonists, a new injectable glucose-lowering agent working through the incretin system of the gastrointestinal tract, has shown in an in-vitro study using exenatide an attenuation of osteoblastic differentiation and calcification of SMCs in both a time-dependent and dose-dependent manner, alongside a decrease in the expression of RANKL 69. Endothelin receptor agonists used to treat hypertension may also hold therapeutic value, as they have been shown to be effective against VSMC calcification in vitro 52 and also in rat models of VC 70. In other recent studies, it has been observed that aortic calcification can be attenuated by a monoclonal antibody to interleukin-1β (01BSUR, Novartis) in ldlr−/− mice, highlighting a new potential therapy for VC that targets the link between CVD and inflammation 71.

Back to Top | Article Outline

Conclusion

VC is common, accelerated by diabetes, and is associated with poor CV outcomes, that is, increased morbidity and mortality. The OPG/RANKL/TRAIL system and the relationship between the three proteins appear to regulate and control the mechanisms underlying the pathogenesis of VC. Medications that can modify the OPG/RANKL/TRAIL system therefore offer an opportunity to slow down the progression of VC in patients with and without diabetes.

Back to Top | Article Outline

Acknowledgements

Conflicts of interest

There are no conflicts of interest.

Back to Top | Article Outline

References

1. Grundy SM, Benjamin IJ, Burke GL, Chait A, Eckel RH, Howard BV, et al. Diabetes and cardiovascular disease: a statement for healthcare professionals from the American Heart Association. Circulation 1999; 100:1134–1146.
2. Hao JS, Cai J, Towler DA. Molecular mechanisms of vascular calcification: lessons learned from the aorta. Arterioscler Thromb Vasc Biol 2006; 26:1423–1430.
3. Demer LL. A skeleton in the atherosclerosis closet. Circulation 1995; 92:2029–2032.
4. Kizu A, Jono S. Mechanism of vascular calcification. Clin Calcium 2004; 14:92–96.
5. Zhang Y, Khan D, Delling J, Tobiasch E. Mechanisms underlying the osteo- and adipo-differentiation of human mesenchymal stem cells. ScientificWorldJournal 2012; 2012:793823.
6. Chen NX, Moe SM. Vascular calcification: pathophysiology and risk factors. Curr Hypertens Rep 2012; 14:228–237.
7. Abedin M, Tintut Y, Demer LL. Vascular calcification: mechanisms and clinical ramifications. Arterioscler Thromb Vasc Biol 2004; 24:1161–1170.
8. Amann K. Media calcification and intima calcification are distinct entities in chronic kidney disease. Clin J Am Soc Nephrol 2008; 3:1599–1605.
9. Demer LL, Tintut Y. Vascular calcification: pathobiology of a multifaceted disease. Circulation 2008; 117:2938–2948.
10. Budoff MJ, Hokanson JE, Nasir K, Shaw LJ, Kinney GL, Chow D, et al. Progression of coronary artery calcium predicts all-cause mortality. JACC Cardiovasc Imaging 2010; 3:1229–1236.
11. Detrano R, Guerci AD, Carr JJ, Bild DE, Burke G, Folsom AR, et al. Coronary calcium as a predictor of coronary events in four racial or ethnic groups. N Engl J Med 2008; 358:1336–1345.
12. Morrish NJ, Wang SL, Stevens LK, Fuller JH, Keen H. Mortality and causes of death in the WHO multinational study of vascular disease in diabetes. Diabetologica 2001; 44:S14–S21.
13. Shao JS, Cheng SL, Sadhu J, Towler DA. Inflammation and the osteogenic regulation of vascular calcification: a review and perspective. Hypertension 2010; 55:579–592.
14. Sage AP, Tintut Y, Demer LL. Regulatory mechanisms in vascular calcification. Nat Rev Cardiol 2010; 7:528–536.
15. Zhu D, Mackenzie NC, Farquharson C, Macrae VE. Mechanisms and clinical consequences of vascular calcification. Front Endocrinol (Lausanne) 2012; 3:95.
16. Hofbauer LC, Schoppet M. Clinical implications of the osteoprotegerin/RANKL/RANK system for bone and vascular diseases. JAMA 2004; 292:490–495.
17. Bucay N, Sarosi I, Dunstan CR, Morony S, Tarpley J, Capparelli C, et al. Osteoprotegerin-deficient mice develop early onset osteoporosis and arterial calcification. Genes Dev 1998; 12:1260–1268.
18. Morony S, Tintut Y, Zhang Z, Cattley RC, Van G, Dwyer D, et al. Osteoprotegerin inhibits vascular calcification without affecting atherosclerosis in ldlr(−/−) mice. Circulation 2008; 117:411–420.
19. Price PA, June HH, Buckley JR, Williamson MK. Osteoprotegerin inhibits artery calcification induced by warfarin and by vitamin D. Arterioscler Thromb Vasc Biol 2001; 21:1610–1616.
20. Panizo S, Cardus A, Encinas M, Parisi E, Valcheva P, López-Ongil S, et al. RANKL increases vascular smooth muscle cell calcification through a RANK-BMP4-dependent pathway. Circ Res 2009; 104:1041–1048.
21. Ndip A, Williams A, Jude EB, Serracino-Inglott F, Richardson S, Smyth JV, et al. The RANKL/RANK/OPG signaling pathway mediates medial arterial calcification in diabetic Charcot neuroarthropathy. Diabetes 2011; 60:2187–2219.
22. Kaden JJ, Bickelhaupt S, Grobholz R, Haase KK, Sarikoç A, Kiliç R, et al. Receptor activator of nuclear factor kappaB ligand and osteoprotegerin regulate aortic valve calcification. J Mol Cell Cardiol 2004; 36:57–66.
23. Olesen M, Skov V, Mechta M, Mumm BH, Rasmussen LM. No influence of OPG and its ligands, RANKL and TRAIL, on proliferation and regulation of the calcification process in primary human vascular smooth muscle cells. Mol Cell Endocrinol 2012; 362:149–156.
24. Couri CE, da Silva GA, Martinez JA, Pereira FA, de Paula FJ. Monckeberg’s sclerosis – is the artery the only target of calcification? BMC Cardiovasc Disord 2005; 5:34.
    25. Piers LH, Salachova F, Slart RH, Vliegenthart R, Dikkers R, Hospers FA, et al. The role of coronary artery calcification score in clinical practice. BMC Cardiovasc Disord 2008; 8:38.
      26. Callegari A, Coons ML, Ricks JL, Rosenfeld ME, Scatena M. Increased calcification in osteoprotegerin-deficient smooth muscle cells: dependence on receptor activator of NF-κB ligand and interleukin 6. J Vasc Res 2014; 51:118–131.
      27. Schoppet M, Al-Fakhri N, Franke FE, Katz N, Barth PJ, Maisch B, et al. Localization of osteoprotegerin, tumor necrosis factor-related apoptosis-inducing ligand, and receptor activator of nuclear factor-kappaB ligand in Mönckeberg’s sclerosis and atherosclerosis. J Clin Endocrinol Metab 2004; 89:4104–4112.
      28. Di Bartolo BA, Kavurma MM. Regulation and function of Rankl in arterial calcification. Curr Pharm Des 2014; 20:5853–5861.
      29. Secchiero P, Candido R, Corallini F, Zacchigna S, Toffoli B, Rimondi E, et al. Systemic tumor necrosis factor-related apoptosis-inducing ligand delivery shows antiatherosclerotic activity in apolipoprotein E-null diabetic mice. Circulation 2006; 114:1522–1530.
      30. Zauli G, Rimondi E, Nicolin V, Melloni E, Celeghini C, Secchiero P. TNF-related apoptosis-inducing ligand (TRAIL) blocks osteoclastic differentiation induced by RANKL plus M-CSF. Blood 2004; 104:2044–2050.
      31. Zauli G, Rimondi E, Stea S, Baruffaldi F, Stebel M, Zerbinati C, et al. TRAIL inhibits osteoclastic differentiation by counteracting RANKL-dependent p27Kip1 accumulation in pre-osteoclast precursors. J Cell Physiol 2008; 214:117–125.
      32. Forde H, Harper E, Davenport C, Rochfort KD, Wallace R, Murphy RP, et al. The beneficial pleiotropic effects of tumour necrosis related factor apoptosis inducing ligand (TRAIL) within the vasculature: a review of the literature. Atherosclerosis 2016; 247:87–96.
      33. Byon CH, Sun Y, Chen J, Yuan K, Mao X, Heath JM, et al. Runx2-upregulated receptor activator of nuclear factor κB ligand in calcifying smooth muscle cells promotes migration and osteoclastic differentiation of macrophages. Arterioscler Thromb Vasc Biol 2011; 31:1387–1396.
      34. Eddahibi S, Guignabert C, Barlier-Mur AM, Dewachter L, Fadel E, Dartevelle P, et al. Cross talk between endothelial and smooth muscle cells in pulmonary hypertension: critical role for serotonin-induced smooth muscle hyperplasia. Circulation 2006; 113:1857–1864.
      35. Chiu JJ, Usami S, Chien S. Vascular endothelial responses to altered shear stress: pathologic implications for atherosclerosis. Ann Med 2009; 41:19–28.
      36. Reinhard H, Lajer M, Gall MA, Tarnow L, Parving HH, Rasmussen LM, Rossing P. Osteoprotegerin and mortality in type 2 diabetic patients. Diabetes Care 2010; 33:2561–2566.
      37. O’Sullivan EP, Ashley DT, Davenport C, Devlin N, Crowley R, Agha A, et al. Osteoprotegerin and biomarkers of vascular inflammation in type 2 diabetes. Diabetes Metab Res Rev 2010; 26:496–502.
      38. Abedin M, Omland T, Ueland T, Khera A, Aukrust P, Murphy SA, et al. Relation of osteoprotegerin to coronary calcium and aortic plaque (from the Dallas Heart Study). Am J Cardiol 2007; 99:513–518.
      39. Schoppet M, Sattler AM, Schaefer JR, Herzum M, Maisch B, Hofbauer LC. Increased osteoprotegerin serum levels in men with coronary artery disease. J Clin Endocrinol Metab 2003; 88:1024–1028.
      40. Ziegler S, Kudlacek S, Luger A, Minar E. Osteoprotegerin plasma concentrations correlate with severity of peripheral artery disease. Atherosclerosis 2005; 182:175–180.
      41. Omland T, Ueland T, Jansson AM, Persson A, Karlsson T, Smith C, et al. Circulating osteoprotegerin levels and long-term prognosis in patients with acute coronary syndromes. J Am Coll Cardiol 2008; 51:627–633.
      42. Higgins CL, Isbilir S, Basto P, Chen IY, Vaduganathan M, Vaduganathan P, et al. Distribution of alkaline phosphatase, osteopontin, rank ligand and osteoprotegerin in calcified human carotid atheroma. Protein J 2015; 34:315–328.
      43. Jung CH, Lee WY, Kim SY, Jung JH, Rhee EJ, Park CY, et al. The relationship between coronary artery calcification score, plasma osteoprotegerin level and arterial stiffness in asymptomatic type 2 DM. Acta Diabetol 2010; 47:145–152.
      44. Gaudio A, Privitera F, Pulvirenti I, Canzonieri E, Rapisarda R, Fiore CE. Relationships between osteoprotegerin, receptor activator of the nuclear factor kB ligand and serum levels and carotid intima–media thickness in patients with type 2 diabetes mellitus. Panminerva Med 2014; 56:221–225.
      45. Rozas Moreno P, Reyes García R, García-Martín A, Varsavsky M, García-Salcedo JA, Muñoz-Torres M. Serum osteoprotegerin: bone or cardiovascular marker in type 2 diabetes males? J Endocrinol Invest 2013; 36:16–20.
      46. Poulsen MK, Nybo M, Dahl J, Hosbond S, Poulsen TS, Johansen A, et al. Plasma osteoprotegerin is related to carotid and peripheral arterial disease, but not to myocardial ischemia in type 2 diabetes mellitus. Cardiovasc Diabetol 2011; 10:76.
      47. Tavintharan S, Pek LT, Liu JJ, Ng XW, Yeoh LY, Su Chi L, Chee Fang S. Osteoprotegerin is independently associated with metabolic syndrome and microvascular complications in type 2 diabetes mellitus. Diab Vasc Dis Res 2014; 11:359–362.
      48. Anand DV, Lim E, Darko D, Bassett P, Hopkins D, Lipkin D, et al. Determinants of progression of coronary artery calcification in type 2 diabetes role of glycemic control and inflammatory/vascular calcification markers. J Am Coll Cardiol 2007; 50:2218–2225.
      49. Giaginis C, Papadopouli A, Zira A, Katsargyris A, Klonaris C, Theocharis S. Correlation of plasma osteoprotegerin (OPG) and receptor activator of the nuclear factor κB ligand (RANKL) levels with clinical risk factors in patients with advanced carotid atherosclerosis. Med Sci Monit 2012; 18:CR597–CR604.
      50. Loncar G, Bozic B, Cvorovic V, Radojicic Z, Dimkovic S, Markovic N, et al. Relationship between RANKL and neuroendocrine activation in elderly males with heart failure. Endocrine 2010; 37:148–156.
      51. Mohammadpour AH, Shamsara J, Nazemi S, Ghadirzadeh S, Shahsavand S, Ramezani M. Evaluation of RANKL/OPG serum concentration ratio as a new biomarker for coronary artery calcification: a pilot study. Thrombosis 2012; 2012:306263.
      52. Wu M, Rementer C, Giachelli CM. Vascular calcification: an update on mechanisms and challenges in treatment. Calcif Tissue Int 2013; 93:365–373.
      53. Miyazaki T, Tokimura F, Tanaka S. A review of denosumab for the treatment of osteoporosis. Patient Prefer Adherence 2014; 8:463–471.
      54. Kostenuik PJ, Nguyen HQ, McCabe J, Warmington KS, Kurahara C, Sun N, et al. Denosumab, a fully human monoclonal antibody to RANKL, inhibits bone resorption and increases BMD in knock-in mice that express chimeric (murine/human) RANKL. J Bone Miner Res 2009; 24:182–195.
      55. Helas S, Goettsch C, Schoppet M, Zeitz U, Hempel U, Morawietz H, et al. Inhibition of receptor activator of NF-kappaB ligand by denosumab attenuates vascular calcium deposition in mice. Am J Pathol 2009; 175:473–478.
      56. Samelson EJ, Miller PD, Christiansen C, Daizadeh NS, Grazette L, Anthony MS, et al. RANKL inhibition with denosumab does not influence 3-year progression of aortic calcification or incidence of adverse cardiovascular events in postmenopausal women with osteoporosis and high cardiovascular risk. J Bone Miner Res 2014; 29:450–457.
      57. Liu M, Xiang G, Lu J, Xiang L, Dong J, Mei W. TRAIL protects against endothelium injury in diabetes via Akt-eNOS signaling. Atherosclerosis 2014; 237:718–724.
      58. Di Bartolo BA, Cartland SP, Harith HH, Bobryshev YV, Schoppet M, Kavurma MM. TRAIL-deficiency accelerates vascular calcification in atherosclerosis via modulation of RANKL. PLoS One 2013; 8:e74211.
      59. Boskey A. Bone mineral crystal size. Osteoporos Int 2003; 14:S16–S21.
      60. Persy V, De Broe M, Ketteler M. Bisphosphonates prevent experimental vascular calcification: treat the bone to cure the vessels? Kidney Int 2006; 70:1537–1538.
      61. Nitta K, Akiba T, Suzuki K, Uchida K, Watanabe R, Majima K, et al. Effects of cyclic intermittent etidronate therapy on coronary artery calcification in patients receiving long-term hemodialysis. Am J Kidney Dis 2004; 44:680–688.
      62. Toussaint ND, Lau KK, Strauss BJ, Polkinghorne KR, Kerr PG. Effect of alendronate on vascular calcification in CKD stages 3 and 4: a pilot randomized controlled trial. Am J Kidney Dis 2010; 56:57–68.
      63. Shao JS, Cheng SL, Charlton-Kachigian N, Loewy AP, Towler DA. Teriparatide (human parathyroid hormone (1–34)) inhibits osteogenic vascular calcification in diabetic low density lipoprotein receptor-deficient mice. J Biol Chem 2003; 278:50195–50202.
      64. Novaro GM, Tiong IY, Pearce GL, Lauer MS, Sprecher DL, Griffin BP. Effect of hydroxymethylglutaryl coenzyme a reductase inhibitors on the progression of calcific aortic stenosis. Circulation 2001; 104:2205–2209.
      65. Iijima K, Ito Y, Son BK, Akishita M, Ouchi Y. Pravastatin and olmesartan synergistically ameliorate renal failure-induced vascular calcification. J Atheroscler Thromb 2014; 21:917–929.
      66. Lenglet S, Quercioli A, Fabre M, Galan K, Pelli G, Nencioni A, et al. Statin treatment is associated with reduction in serum levels of receptor activator of NF-κB ligand and neutrophil activation in patients with severe carotid stenosis. Mediators Inflamm 2014; 2014:720987.
      67. Loomba RS, Arora R. Statin therapy and aortic stenosis: a systematic review of the effects of statin therapy on aortic stenosis. Am J Ther 2010; 17:e110–e114.
      68. Puri R, Nicholls SJ, Shao M, Kataoka Y, Uno K, Kapadia SR, et al. Impact of statins on serial coronary calcification during atheroma progression and regression. J Am Coll Cardiol 2015; 65:1273–1282.
      69. Zhan JK, Tan P, Wang YJ, Wang Y, He JY, Tang ZY, et al. Exenatide can inhibit calcification of human VSMCs through the NF-kappaB/RANKL signaling pathway. Cardiovasc Diabetol 2014; 13:153.
      70. Essalihi R, Ouellette V, Dao HH, McKee MD, Moreau P. Phenotypic modulation of vascular smooth muscle cells during medial arterial calcification: a role for endothelin? J Cardiovasc Pharmacol 2004; 44:S147–S150.
      71. Awan Z, Denis M, Roubtsova A, Essalmani R, Marcinkiewicz J, Awan A, et al. Reducing vascular calcification by anti-IL-1β monoclonal antibody in a mouse model of familial hypercholesterolemia. Angiology 2016; 67:157–167.
      Keywords:

      cardiovascular disease; osteoprotegerin; receptor activator of nuclear factor-κB ligand; tumor necrosis factor-related apoptosis-inducing ligand; vascular calcification

      © 2018Wolters Kluwer Health Lippincott Williams Wilkins