QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) All Versions of this Article: dmd.106.009860v1 34/8/1417    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Oitate, M. Articles by Ikeda, T. Search for Related Content PubMed PubMed Citation Articles by Oitate, M. Articles by Ikeda, T.

COVALENT BINDING OF RADIOACTIVITY FROM [¹⁴C]ROFECOXIB, BUT NOT [¹⁴C]CELECOXIB OR [¹⁴C]CS-706, TO THE ARTERIAL ELASTIN OF RATS

Drug Metabolism and Pharmacokinetics Research Laboratories (M.O., K.Ko., S.I., K.Ka., T.I.) and R&D Project Management Department (T.H.), Sankyo Co., Ltd., Tokyo, Japan

(Received February 20, 2006; accepted May 2, 2006)

	Abstract

Top Abstract Materials and Methods Results Discussion References

 
Rofecoxib is a cyclooxygenase-2 (COX-2) inhibitor that has been withdrawn from the market because of an increased risk of cardiovascular (CV) events. With a special focus on the arteries, the distribution profiles of radioactivity in rats orally administered [¹⁴C]rofecoxib were investigated in comparison with two other COX-2 inhibitors, [¹⁴C]celecoxib and [¹⁴C]CS-706 (2-(4-ethoxyphenyl)-4-methyl 1-(4-sulfamoylphenyl)-1H-pyrrole), a novel selective COX-2 inhibitor. Whole-body autoradioluminography and quantitative determination of the tissue concentrations showed that considerable radioactivity is retained by and accumulated in the thoracic aorta of rats after oral administration of [¹⁴C]rofecoxib, but not [¹⁴C]celecoxib or [¹⁴C]CS-706. Acid, organic solvent, and proteolytic enzyme treatments of aorta retaining high levels of radioactivity from [¹⁴C]rofecoxib demonstrated that most of the radioactivity is covalently bound to elastin. In agreement with this result, the radioactivity was found to be highly localized on the elastic fibers in the aorta by microautoradiography. The retention of radioactivity on the elastic fibers was also observed in the aortic arch and the coronary artery. These findings indicate that [¹⁴C]rofecoxib and/or its metabolite(s) are covalently bound to elastin in the arteries. These data are consistent with the suggestion of modified arterial elasticity leading to an increased risk of CV events after long-term treatment with rofecoxib.

In the last few years, it has been reported that other selective COX-2 inhibitors (e.g., etoricoxib, parecoxib/valdecoxib, and celecoxib) and nonselective NSAIDs (e.g., naproxen) may also have a potential for increased CV risk (Bombardier et al., 2000; Ott et al., 2003; FDA, 2004; FDA Advisory Committee.com, 2004; NIH, 2004; Aldington et al., 2005; Krotz et al., 2005; Nussmeier et al., 2005). However, rofecoxib differs in the following ways: 1) a significantly greater frequency and higher odds of CV events (Mamdani et al., 2004; Solomon et al., 2004a; Graham et al., 2005; Kimmel et al., 2005); 2) a shorter period and a lower dose (even at the clinical dose) leading to the incidence of CV events; and 3) an earlier onset and a greater hypertensive effect correlating closely with CV risk (Brinker et al., 2004; Solomon et al., 2004b; Wolfe et al., 2004; Fredy et al., 2005). Therefore, it is suggested that rofecoxib could have distinctive mechanisms or more potent toxic activity leading to CV risks, in comparison with other selective COX-2 inhibitors or nonselective NSAIDs. Consequently, it is vital to investigate rofecoxib by comparing it with other selective COX-2 inhibitors to clarify its relevance to increased CV events.

Several hypotheses have been proposed to explain the mechanism for the increased risk of CV events with rofecoxib. McAdam et al. (1999) suggested the endothelial prostacyclin (PGI₂)/thromboxane A₂ (TxA₂) imbalance theory, whereby the CV complications caused by selective COX-2 inhibitors might be partially due to an imbalance of the concentration ratio of two prostanoids with major CV actions: PGI₂, a vasodilator and inhibitor of platelet aggregation, and TxA₂, a vasoconstrictor and promotor of platelet aggregation. That is, selective COX-2 inhibitors diminish the production of PGI₂ in the endothelium, but not TxA₂ in the platelets, so that the relative concentration of TxA₂ increases around the affected area, which might increase the risks. Walter et al. (2004) proposed the pro-oxidant effect theory, whereby rofecoxib, which is a sulfone-type COX-2 inhibitor, but not celecoxib (sulfonamide-type COX-2 inhibitor) or nonselective NSAIDs, promotes oxidative damage to low-density lipoprotein and phospholipids in vitro, and this action might lead to atherogenesis in vivo. In addition, Pope et al. (1993) and Johnson et al. (1994) proposed the blood pressure elevation theory, in which NSAIDs and selective COX-2 inhibitors disrupt the production of prostaglandins, which play an important homeostatic role in the kidney. The resulting sodium and water retention can contribute to blood pressure elevation. The higher risk potential of rofecoxib on the CV events can be supported only by the Walter et al. (2004) hypothesis. However, it may not be enough to distinguish rofecoxib from other COX-2 inhibitors and NSAIDs in terms of the risks.

View larger version (14K): [in this window] [in a new window]   FIG. 1. Chemical structures of rofecoxib, celecoxib, and CS-706. The asterisk indicates the position of the radiolabel.

In the present study, we investigated the distribution profiles of radioactivity after oral administration of [¹⁴C]rofecoxib to rats, especially in its retention by and accumulation in the thoracic aorta, by comparing it with [¹⁴C]celecoxib and [¹⁴C]CS-706 as references (Fig. 1). Aorta samples were collected after administration of [¹⁴C]rofecoxib and treated with acid, organic solvent, and proteolytic enzymes to demonstrate that [¹⁴C]rofecoxib and/or its metabolite(s) are covalently bound to a protein of the aorta. Microautoradiographic observation of the radioactivity localized in the aorta was also conducted.

	Materials and Methods

Top Abstract Materials and Methods Results Discussion References

 
Chemicals and Reagents. [¹⁴C]Rofecoxib (59 mCi/mmol for microautoradiography and 17 mCi/mmol for the other studies), [¹⁴C]celecoxib (13 mCi/mmol), and [¹⁴C]CS-706 (14 mCi/mmol) were synthesized at GE Healthcare Bio-Sciences (Little Chalfont, Buckinghamshire, UK; Fig. 1). The radiochemical purity of these compounds was more than 98% by radiodetection-high-performance liquid chromatography analysis. Nonlabeled rofecoxib, celecoxib, and CS-706 were synthesized at Sankyo Co., Ltd. (Tokyo, Japan). All other reagents and solvents used were commercially available and were of extra pure, guaranteed, or high-performance liquid chromatography grade.

Dosing of Animals. Male Sprague-Dawley rats (7 weeks old, Charles River Japan, Inc., Yokohama, Japan) were used after one or more weeks of acclimatization. Rats were housed in a temperature-controlled room with a 12-h light/dark cycle. Their body weights ranged from 160 g to 260 g at the start of administration. For the single oral administration, rats were fasted overnight before dosing and through 8 h postdose. For the repeated administrations, rats were fasted only on the first day. Water was available ad libitum throughout the study.

[¹⁴C]Rofecoxib was orally administered at 2 ml/kg as a solution in polyethylene glycol 400. [¹⁴C]Celecoxib and [¹⁴C]CS-706 were orally administered at 2 ml/kg as a solution in a mixture of N,N-dimethylacetamide, Tween 80, and distilled water (5/20/75, v/v/v). The dosing solutions were prepared shortly before dosing at the same specific radioactivity within the same study (range 68–370 µCi/kg body weight).

Whole-Body Autoradioluminography. Rats (one animal at each time point) were euthanized by deep anesthesia with diethyl ether at 0.5, 2, 6, 24, and 48 h after single oral administration (2 mg/kg) of [¹⁴C]rofecoxib, [¹⁴C]celecoxib, or [¹⁴C]CS-706, at 48 h after 3-day repeated administrations of [¹⁴C]rofecoxib (2 mg/kg) and at 48 h and 10 days after 7-day repeated administrations of [¹⁴C]rofecoxib (2 mg/kg). The rats were frozen in n-hexane/dry ice, embedded in a gel of carboxymethyl cellulose (ca. 5% w/v), and frozen again in n-hexane/dry ice. The frozen blocks were sliced with Cryomacrocut (CM3600; Leica Microsystems Nussloch GmbH, Nussloch, Germany) at approximately –25°C to prepare whole-body sections of 50-µm thickness. The whole-body sections obtained were freeze-dried at approximately –25°C for 48 h. After freeze-drying, the sections were covered with a protective film (4 µm, DIAFOIL membrane; Mitsubishi Polyester Film Corp., Tokyo, Japan) and placed in contact with imaging plates (BAS-MS2040; Fuji Photo Film Co., Ltd., Tokyo, Japan) for approximately 24 h. Finally, the imaging plates were subjected to image analysis using a Bio Imaging Analyzer (BAS-2500; Fuji Photo Film Co., Ltd.) to obtain whole-body autoradioluminograms (resolution 50 µm, gradation 256, sensitivity 10,000, latitude 4).

Quantitative Tissue Distribution. After single oral administration of [¹⁴C]rofecoxib, [¹⁴C]celecoxib, or [¹⁴C]CS-706 to the rats (2 mg/kg, n = 3), blood samples were taken from the abdominal aorta under diethyl ether anesthesia at 0.5, 2, 6, 24, and 48 h postdose. Subsequently, the liver, kidney, lung, aorta, cartilage (auricular), and skin (back) were collected from each carcass. After repeated administrations of [¹⁴C]rofecoxib to rats (2 mg/kg, n = 3) for 3 days or 7 days, the blood and the above described tissues were collected at 48 h postdose. Blood samples were centrifuged (4°C, 1680g, 10 min) to obtain plasma samples.

Acid, Organic Solvent, and Proteolytic Enzyme Treatments of Thoracic Aortas. At 24 h after single oral administration of [¹⁴C]rofecoxib (2 mg/kg, n = 10), rats were euthanized by exsanguination under diethyl ether anesthesia and the aorta samples were collected, pooled, and weighed. The samples were homogenized in isotonic saline (5% w/v) using a motor-driven homogenizer, and 0.2 ml of the homogenate was removed for determination of the radioactivity. To the remaining homogenate, 30 ml of 0.9 M trichloroacetic acid (TCA) was added to precipitate the proteins. Then, the mixture was centrifuged at 2000g at room temperature for 10 min. The supernatant was discarded, and the precipitate was washed by resuspension and centrifugation successively with 0.6 M TCA, 80% (v/v) methanol, and 100% methanol. This process was repeated twice.

The resulting precipitate (wet weight 636.9 mg) was resuspended in 5 ml of 0.1 M Tris-HCl buffer (pH 8.0) containing collagenase (5000 units/ml, from Clostridium histolyticum; Wako Pure Chemical Industries, Ltd., Osaka, Japan) and incubated at 37°C for 16 h. After centrifugation (2000g, room temperature, 10 min), the supernatant containing collagen digests was collected. The precipitate was suspended in 3 ml of methanol, mixed on a vortex shaker, and recentrifuged. The supernatants were collected as methanol washings. This process of washing was repeated three times. The residue was air-dried, resuspended, and incubated in 5 ml of 0.1 M Tris-HCl buffer (pH 8.5) containing elastase (600 units/ml, from porcine pancreas; Wako Pure Chemical Industries, Ltd.) at 37°C for 16 h. After the same washing process as described for the collagenase treatment, the remaining dried residue was resuspended and incubated in 6 ml of 0.1 M sodium phosphate buffer (pH 7.5) containing pronase (1000 units/ml, from Streptomyces griseus; Merck, Darmstadt, Germany) at 37°C for 16 h. In the same manner as the collagenase and elastase treatments, the precipitate after pronase treatment was washed with methanol. The combined digests and methanol washings collected after each enzyme treatment were dried in vacuo.

View larger version (72K): [in this window] [in a new window]   FIG. 2. Whole-body autoradioluminograms 2 or 48 h after single oral administration of [14C]COX-2 inhibitors to rats at a dose of 2 mg/kg (n = 1/time point).

Radioactivity Measurements. An aliquot of the plasma sample was placed in a vial and mixed with a tissue solubilizer, NCS-II (GE Healthcare BioSciences; 1 ml). Each proteolytic fraction of the aorta was solubilized each in 1 ml of NCS-II, and an aliquot of each solution was transferred to a vial. Tissues or organs were measured for the wet weight and solubilized each in 2 ml of NCS-II under constant shaking at ca. 55°C. In the case of colored tissues, decolorization with 30% hydrogen peroxide (0.3 ml) was done to avoid color quenching in the liquid scintillation counting. After decolorization and solubilization, these samples were mixed with 10 ml of a liquid scintillator, Hionic-Fluor (PerkinElmer Life and Analytical Sciences, Boston, MA) and were subjected to radioactivity measurement by a liquid scintillation counter, model 2300TR (PerkinElmer Life and Analytical Sciences).

The radioactivity in the plasma and tissues was calculated as an equivalent value of ¹⁴C-labeled compound and expressed as a concentration per milliliter (for plasma) or per gram (for tissues). The ratio of the concentration in the tissue to that in the plasma was calculated as a K_p value. The radioactivity value of each proteolytic fraction of the aorta was converted to a percentage of the total tissue-bound radioactivity, which is not extractable by TCA and methanol treatments.

Statistical Analysis. Statistical analysis of the experimental data was performed using Student's t test. p < 0.05 was regarded as statistically significant.

	Results

Top Abstract Materials and Methods Results Discussion References

 
Whole-Body Autoradioluminography. After single oral administration of [¹⁴C]rofecoxib, [¹⁴C]celecoxib, or [¹⁴C]CS-706, high levels of radioactivity were observed throughout the whole body, and there was no marked difference in the distribution profile among the three compounds up to 6 h, as shown representatively in the autoradioluminograms at 2 h (Fig. 2, left panels). At 24 and 48 h after the administration of [¹⁴C]celecoxib or [¹⁴C]CS-706, the radioactivity was only observed in the gastrointestinal contents. In contrast, in the case of [¹⁴C]rofecoxib, high levels of radioactivity were observed in the thoracic aorta and liver, as shown representatively in the autoradioluminograms at 48 h (Fig. 2, right panels). Furthermore, at 48 h after 3- or 7-day repeated administrations of [¹⁴C]rofecoxib, the radioactivity appeared to have accumulated in the aorta and interspinal ligaments in a dosing frequency-dependent manner (Fig. 3, A and B). In addition, the radioactivity in these tissues was still clearly observed 10 days after the 7-day repeated administrations (Fig. 3C), when the radioactivity was almost completely cleared from the body.

View larger version (102K): [in this window] [in a new window]   FIG. 3. Whole-body autoradioluminograms after repeated oral administrations of [14C]rofecoxib to rats at a dose of 2 mg/kg (n = 1/time point). A, 48 h after 3-day repeated administrations; B, 48 h after 7-day repeated administrations; C, 10 days after 7-day repeated administrations.

View larger version (25K): [in this window] [in a new window]   FIG. 4. Radioactive concentrations in plasma and tissues after oral administration of [14C]COX-2 inhibitors to rats at a dose of 2 mg/kg (n = 3, mean ± S.D.). A, C, and D, single administration: liver (open circle), kidney (open triangle), lung (open square), plasma (open diamond), aorta (closed circle), auricular cartilage (closed triangle), and skin (X). B, single and multiple administration of [14C]rofecoxib (once daily for 1, 3, or 7 days). p values were calculated by Student's t test (*, p < 0.05; **, p < 0.01).

After single oral administration of [¹⁴C]celecoxib or [¹⁴C]CS-706 (Fig. 4, C or D), the radioactivity was distributed to all the tissues examined at 0.5 h postdose, and the time to reach the C_max (T_max) was between 0.5 and 2 h, with a plasma concentration of 0.5 or 0.4 µg Eq/ml at 2 h postdose. Thereafter, the plasma concentration declined almost in parallel with the decrease in the concentrations in all the tissues, including the aorta. At 48 h, negligible concentrations were observed in all the tissues.

Acid, Organic Solvent, and Proteolytic Enzyme Treatments of Thoracic Aortas. The combined thoracic aorta samples collected at 24 h after single oral administration of [¹⁴C]rofecoxib to the rats were treated by successive extraction with 0.6 M TCA, 80% (v/v) methanol, and 100% methanol, and 71.5% of the radioactivity that existed initially in the aorta remained in the final precipitate fraction, which was considered to be bound covalently to proteins in the aorta. The resultant precipitated fraction was enzymatically treated successively with collagenase, elastase, and pronase. As shown in Table 1, most of the radioactivity (91.4% of total) was recovered in the elastolytic fraction. The radioactivity recovered in the fractions after collagenase and pronase treatments was 4.4% and 2.7%, respectively, and the radioactivity in the residue after the treatments with the proteolytic enzymes was 1.4%.

Microautoradiography. The intra-arterial localization of the radioactivity at 48 h after 7-day repeated oral administrations of [¹⁴C]rofecoxib to rats was investigated by microautoradiographs with elastin staining, as shown in Fig. 5. In the thoracic aorta and aortic arch (Fig. 5, A and B), the three basic layers (intima, media, and adventia) were seen, and the elastic fibers made visible by elastin staining mainly existed in the media. The number of elastic fibers in the aortic arch was more than that found in the thoracic aorta. The radioactivity detected as black-silver grains was mainly located on the elastic fibers (media), not on the intima or adventia, in good agreement with the results of the enzymatic fractionation (Table 1). In the coronary artery (Fig. 5C), radioactivity was also detected on the elastic fibers even though the elastic fiber layer was much thinner and fainter than those of the thoracic aorta and aortic arch.

View larger version (62K): [in this window] [in a new window]   FIG. 5. Microautoradiograms showing the distribution of radioactivity 48 h after 7-day repeated administration of [14C]rofecoxib to a rat at a dose of 2 mg/kg. A, thoracic aorta. Original magnification 500x. B, aortic arch. Original magnification 500x. C, coronary artery. Original magnification 500x. L, lumen; I, intima; M, media; A, adventia; El, elastic fiber.

	Discussion

Top Abstract Materials and Methods Results Discussion References

Rofecoxib has a five-member lactone ring (3-phenyl-2(5H)-furanone) in its structure, whereas celecoxib and CS-706 have no such lactone ring (Fig. 1). Recently, Reddy and Corey (2005) proposed the following mechanism for chronic human toxicity such as CV events. That is, the lactone ring in rofecoxib is capable of undergoing spontaneous oxidation as it circulates to the vasculature and oxygenated tissues in vivo, and one of the resulting metabolites, its maleic anhydride form, has the potential to react with nucleophilic groups in biomolecules, especially amino acids. Furthermore, it is also thought to be possible that the lactone in it can be directly bound to amino acid side chains of biomolecules by enzyme-catalyzed trans-esterification. However, if these hypotheses are correct, it is difficult to explain why the radioactivity is retained only in a limited number of tissues, such as the aorta, ligament, and cartilage.

Regarding the tissues in which the radioactivity was retained and accumulated (aorta, ligament, and auricular cartilage), it was noted that they are all representative connective tissues that have abundant elastin and collagen in their extracellular matrices. Assuming that rofecoxib and/or its metabolite(s) bind covalently to elastin or collagen, its specific distribution to connective tissues would be well explained. Based on this hypothesis, an enzymatic fractionation of the aorta was conducted with elastase and collagenase. At 24 h after single oral administration of [¹⁴C]rofecoxib to rats, most of the aortic radioactivity (71.5% of total) came from the covalently bound fraction which was not extracted by the TCA and methanol treatments. As shown in Table 1, almost all of the radioactivity bound to the aorta was recovered in the elastolytic fraction. In addition, a microautographic study demonstrated that the majority of the radioactivity was clearly located on an elastin-rich region in the thoracic aorta and aortic arch (Fig. 5, A and B), in good agreement with the results of the enzymatic fractionation. Radioactivity was also detected on the elastic fibers of the coronary artery (Fig. 5C), which had much thinner and fainter elastic fibers than the thoracic aorta and aortic arch. These findings strongly indicate that [¹⁴C]rofecoxib and/or its metabolite(s) are covalently bound to the elastin in the arteries.

Elastin is a key extracellular matrix protein that is critical to the elasticity and resilience of the connective tissues and constitutes approximately 50% of the aorta (dry mass), 66% of the ligaments, and 4 to 30% of the cartilage (ear) (Starcher and Galione, 1976; Keith et al., 1977). As well, the pericardium and the heart valves consist of elastin (Elbahnasy et al., 1998; Vesely, 1998). Its structural and functional destruction is clinically relevant to CV diseases such as hypertension (Martyn and Greenwald, 1997; D'Armiento, 2003), aneurysm (Inci and Spetzler, 2000), atherosclerosis (Sandberg et al., 1981), Marfan syndrome (Abraham et al., 1982), pseudoxanthoma elasticum (Raybould et al., 1994), supravalvular aortic stenosis (Li et al., 1997), and Williams syndrome (Lowery et al., 1995). In addition, elastin has a very slow turnover rate with an estimated half-life of about 70 years (Petersen et al., 2002). It is impossible to completely recover elastin function once it has been damaged (Rucker and Dubick, 1984). It was reported that rofecoxib, but not celecoxib, significantly increases systolic blood pressure in only 1 week in humans (Whelton et al., 2002). This might be due to a dysfunction of the elastin in arteries caused by rofecoxib.

From the above information and our present results, it is suggested that rofecoxib and/or its metabolite(s) are bound covalently to the elastin in the arteries, consequently leading to deteriorated elastin function. Considering the relationship between elastin and the diseases mentioned above, a long-lasting arterial dysfunction as a consequence of the covalent binding of rofecoxib may lead to increased CV events, including possible hypertension in the short term. In our view, assuming that the same covalent binding observed in rats occurs in humans only for rofecoxib, the risk of CV events for CS-706 is thought to be less than that for rofecoxib and about the same as that for celecoxib. Further investigations regarding the mechanism of rofecoxib-elastin binding and the resulting toxicity are ongoing in our laboratories.

	Footnotes

 
Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.

doi:10.1124/dmd.106.009860.

ABBREVIATIONS: COX-2, cyclooxygenase-2; CV, cardiovascular; NSAID, nonsteroidal anti-inflammatory drug; PGI₂, prostacyclin; TxA₂, thromboxane A₂; CS-706, 2-(4-ethoxyphenyl)-4-methyl 1-(4-sulfamoylphenyl)-1H-pyrrole; TCA, trichloroacetic acid; K_p, the ratio of concentration in tissue to that in plasma (tissue/plasma).

Address correspondence to: Masataka Oitate, Drug Metabolism and Pharmacokinetics Research Laboratories, Sankyo Co., Ltd., 1-2-58, Hiromachi, Shinagawa-ku, Tokyo 140-8710, Japan. E-mail: masataka{at}sankyo.co.jp

	References

Top Abstract Materials and Methods Results Discussion References

 


Abraham PA, Perejda AJ, Carnes WH, and Uitto J (1982) Marfan syndrome. Demonstration of abnormal elastin in aorta. J Clin Investig 70: 1245–1252.[Medline]

Aldington S, Shirtcliffe P, Weatherall M, and Beasley R (2005) Systematic review and metaanalysis of the risk of major cardiovascular events with etoricoxib therapy. NZ Med J 118: U1684.[Medline]

Bombardier C, Laine L, Reicin A, Shapiro D, Burgos-Vargas R, Davis B, Day R, Ferraz MB, Hawkey CJ, Hochberg MC, et al. (2000) Comparison of upper gastrointestinal toxicity of rofecoxib and naproxen in patients with rheumatoid arthritis. VIGOR Study Group. N Engl J Med 343: 1520–1528.[Abstract/Free Full Text]

Brinker A, Goldkind L, Bonnel R, and Beitz J (2004) Spontaneous reports of hypertension leading to hospitalisation in association with rofecoxib, celecoxib, nabumetone and oxaprozin. Drugs Aging 21: 479–484.[CrossRef][Medline]

D'Armiento J (2003) Decreased elastin in vessel walls puts the pressure on. J Clin Investig 112: 1308–1310.[CrossRef][Medline]

Elbahnasy AM, Shalhav A, Hoenig DM, Figenshau R, and Clayman RV (1998) Bladder wall substitution with synthetic and non-intestinal organic materials. J Urol 159: 628–637.[CrossRef][Medline]

[FDA] Food and Drug Administration (2004) FDA statement on the halting of a clinical trial of the Cox-2 inhibitor Celebrex. Available at: http://www.fda.gov/bbs/topics/news/2004/NEW01144.html.

FDA Advisory Committee.com (2004) Battling Bextra, meta-analyses could be taken up at February COX-2 Advisory Cmte. Available at: http://www.fdaadvisorycommittee.com./FDC/AdvisoryCommittee/Committees/Arthritis+Drugs/021605_cox2day1/0216-1705_Bextra.htm.

Fredy J, Diggins DA Jr, and Morrill GB (2005) Blood pressure in Native Americans switched from celecoxib to rofecoxib. Ann Pharmacother 39: 797–802.[Abstract/Free Full Text]

Graham DJ, Campen D, Hui R, Spence M, Cheetham C, Levy G, Shoor S, and Ray WA (2005) Risk of acute myocardial infarction and sudden cardiac death in patients treated with cyclooxygenase 2 selective and non-selective non-steroidal anti-inflammatory drugs: nested case-control study. Lancet 365: 475–481.[Medline]

Inci S and Spetzler RF (2000) Intracranial aneurysms and arterial hypertension: a review and hypothesis. Surg Neurol 53: 530–540; discussion 540–542.[CrossRef][Medline]

Johnson AG, Nguyen TV, and Day RO (1994) Do nonsteroidal anti-inflammatory drugs affect blood pressure? A meta-analysis. Ann Intern Med 121: 289–300.[Abstract/Free Full Text]

Keith DA, Paz A, Gallop PM, and Glimcher MJ (1977) Histologic and biochemical identification and characterization of an elastin in cartilage. J Histochem Cytochem 25: 1154–1162.[Abstract]

Kimmel SE, Berlin JA, Reilly M, Jaskowiak J, Kishel L, Chittams J, and Strom BL (2005) Patients exposed to rofecoxib and celecoxib have different odds of nonfatal myocardial infarction. Ann Intern Med 142: 157–164.[Abstract/Free Full Text]

Krotz F, Schiele TM, Klauss V, and Sohn HY (2005) Selective COX-2 inhibitors and risk of myocardial infarction. J Vasc Res 42: 312–324.[CrossRef][Medline]

Li DY, Toland AE, Boak BB, Atkinson DL, Ensing GJ, Morris CA, and Keating MT (1997) Elastin point mutations cause an obstructive vascular disease, supravalvular aortic stenosis. Hum Mol Genet 6: 1021–1028.[Abstract/Free Full Text]

Lowery MC, Morris CA, Ewart A, Brothman LJ, Zhu XL, Leonard CO, Carey JC, Keating M, and Brothman AR (1995) Strong correlation of elastin deletions, detected by FISH, with Williams syndrome: evaluation of 235 patients. Am J Hum Genet 57: 49–53.[Medline]

Mamdani M, Juurlink DN, Lee DS, Rochon PA, Kopp A, Naglie G, Austin PC, Laupacis A, and Stukel TA (2004) Cyclo-oxygenase-2 inhibitors versus non-selective non-steroidal anti-inflammatory drugs and congestive heart failure outcomes in elderly patients: a population-based cohort study. Lancet 363: 1751–1756.[CrossRef][Medline]

Martyn CN and Greenwald SE (1997) Impaired synthesis of elastin in walls of aorta and large conduit arteries during early development as an initiating event in pathogenesis of systemic hypertension. Lancet 350: 953–955.[CrossRef][Medline]

McAdam BF, Catella-Lawson F, Mardini IA, Kapoor S, Lawson JA, and FitzGerald GA (1999) Systemic biosynthesis of prostacyclin by cyclooxygenase (COX)-2: the human pharmacology of a selective inhibitor of COX-2. Proc Natl Acad Sci USA 96: 272–277.[Abstract/Free Full Text]

Merck (2004) Merck announces voluntary worldwide withdrawal of VIOXX. Available at: http://www.vioxx.com/vioxx/documents/english/vioxx_press_release.pdf.

[NIH] National Institutes of Health (2004) Use of non-steroidal anti-inflammatory drugs suspended in large Alzheimer's disease prevention trial. Available at: http://www.nih.gov/news/pr/dec2004/od-20.htm.

Nussmeier NA, Whelton AA, Brown MT, Langford RM, Hoeft A, Parlow JL, Boyce SW, and Verburg KM (2005) Complications of the COX-2 inhibitors parecoxib and valdecoxib after cardiac surgery. N Engl J Med 352: 1081–1091.[Abstract/Free Full Text]

Ott E, Nussmeier NA, Duke PC, Feneck RO, Alston RP, Snabes MC, Hubbard RC, Hsu PH, Saidman LJ, and Mangano DT (2003) Efficacy and safety of the cyclooxygenase 2 inhibitors parecoxib and valdecoxib in patients undergoing coronary artery bypass surgery. J Thorac Cardiovasc Surg 125: 1481–1492.[Abstract/Free Full Text]

Petersen E, Wagberg F, and Angquist KA (2002) Serum concentrations of elastin-derived peptides in patients with specific manifestations of atherosclerotic disease. Eur J Vasc Endovasc Surg 24: 440–444.[CrossRef][Medline]

Pope JE, Anderson JJ, and Felson DT (1993) A meta-analysis of the effects of nonsteroidal anti-inflammatory drugs on blood pressure. Arch Intern Med 153: 477–484.[Abstract]

Raybould MC, Birley AJ, Moss C, Hulten M, and McKeown CM (1994) Exclusion of an elastin gene (ELN) mutation as the cause of pseudoxanthoma elasticum (PXE) in one family. Clin Genet 45: 48–51.[Medline]

Reddy LR and Corey EJ (2005) Facile air oxidation of the conjugate base of rofecoxib (Vioxx), a possible contributor to chronic human toxicity. Tetrahedron Lett 46: 927–929.[CrossRef]

Rucker RB and Dubick MA (1984) Elastin metabolism and chemistry: potential roles in lung development and structure. Environ Health Perspect 55: 179–191.[Medline]

Sandberg LB, Soskel NT, and Leslie JG (1981) Elastin structure, biosynthesis and relation to disease states. N Engl J Med 304: 566–579.[Medline]

Solomon DH, Schneeweiss S, Glynn RJ, Kiyota Y, Levin R, Mogun H, and Avorn J (2004a) Relationship between selective cyclooxygenase-2 inhibitors and acute myocardial infarction in older adults. Circulation 109: 2068–2073.[Abstract/Free Full Text]

Solomon DH, Schneeweiss S, Levin R, and Avorn J (2004b) Relationship between COX-2 specific inhibitors and hypertension. Hypertension 44: 140–145.[Abstract/Free Full Text]

Starcher BC and Galione MJ (1976) Purification and comparison of elastins from different animal species. Anal Biochem 74: 441–447.[CrossRef][Medline]

Vesely I (1998) The role of elastin in aortic valve mechanics. J Biomech 31: 115–123.[Medline]

Walter MF, Jacob RF, Day CA, Dahlborg R, Weng Y, and Mason RP (2004) Sulfone COX-2 inhibitors increase susceptibility of human LDL and plasma to oxidative modification: comparison to sulfonamide COX-2 inhibitors and NSAIDs. Atherosclerosis 177: 235–243.[CrossRef][Medline]

Whelton A, White WB, Bello AE, Puma JA, and Fort JG (2002) Effects of celecoxib and rofecoxib on blood pressure and edema in patients > or =65 years of age with systemic hypertension and osteoarthritis. Am J Cardiol 90: 959–963.[CrossRef][Medline]

Wolfe F, Zhao S, and Pettitt D (2004) Blood pressure destabilization and edema among 8538 users of celecoxib, rofecoxib and nonselective nonsteroidal antiinflammatory drugs (NSAID) and nonusers of NSAID receiving ordinary clinical care. J Rheumatol 31: 1143–1151.[Medline]

This article has been cited by other articles:

				M. Oitate, T. Hirota, T. Murai, S.-i. Miura, and T. Ikeda Covalent Binding of Rofecoxib, but Not Other Cyclooxygenase-2 Inhibitors, to Allysine Aldehyde in Elastin of Human Aorta Drug Metab. Dispos., October 1, 2007; 35(10): 1846 - 1852. [Abstract] [Full Text] [PDF]

				K. Kiguchi, L. Ruffino, T. Kawamoto, E. Franco, S.-i. Kurakata, K. Fujiwara, M. Hanai, M. Rumi, and J. DiGiovanni Therapeutic effect of CS-706, a specific cyclooxygenase-2 inhibitor, on gallbladder carcinoma in BK5.ErbB-2 mice Mol. Cancer Ther., June 1, 2007; 6(6): 1709 - 1717. [Abstract] [Full Text] [PDF]

				M. Oitate, T. Hirota, M. Takahashi, T. Murai, S.-i. Miura, A. Senoo, T. Hosokawa, T. Oonishi, and T. Ikeda Mechanism for Covalent Binding of Rofecoxib to Elastin of Rat Aorta J. Pharmacol. Exp. Ther., March 1, 2007; 320(3): 1195 - 1203. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) All Versions of this Article: dmd.106.009860v1 34/8/1417    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Oitate, M. Articles by Ikeda, T. Search for Related Content PubMed PubMed Citation Articles by Oitate, M. Articles by Ikeda, T.