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Glycation end-product cross-link breaker reduces collagen and improves cardiac function in aging diabetic heart

Jing Liu,^1,2 Malthi R. Masurekar,^1,2 Dorothy E. Vatner,^1,2 Garikiparthy N. Jyothirmayi,³ Timothy J. Regan,^3, Stephen F. Vatner,^1,2 Leonard G. Meggs,^2,3 and Ashwani Malhotra^2,3

¹Department of Cell Biology and Molecular Medicine, ²Cardiovascular Research Institute, and ³Department of Medicine, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey 07101

Submitted 5 June 2003 ; accepted in final form 19 August 2003

	ABSTRACT

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Aging and diabetes mellitus (DM) both affect the structure and function of the myocardium, resulting in increased collagen in the heart and reduced cardiac function. As part of this process, hyperglycemia is a stimulus for the production of advanced glycation end products (AGEs), which covalently modify proteins and impair cell function. The goals of this study were first to examine the combined effects of aging and DM on hemodynamics and collagen types in the myocardium in 12 dogs, 9–12 yr old, and second to examine the effects of the AGE cross-link breaker phenyl-4,5-dimethylthazolium chloride (ALT-711) on myocardial collagen protein content, aortic stiffness, and left ventricular (LV) function in the aged diabetic heart. The alloxan model of DM was utilized to study the effects of DM on the aging heart. DM induced in the aging heart decreased LV systolic function (LV ejection fraction fell by 25%), increased aortic stiffness, and increased collagen type I and type III protein content. ALT-711 restored LV ejection fraction, reduced aortic stiffness and LV mass with no reduction in blood glucose level (199 ± 17 mg/dl), and reversed the upregulation of collagen type I and type III. Myocardial LV collagen solubility (%) increased significantly after treatment with ALT-711. These data suggest that an AGE cross-link breaker may have a therapeutic role in aged patients with DM.

diabetes mellitus; alloxan model; myocardium; ALT-711

The first objective of the present investigation was to determine the extent to which collagen types I and III, which account for 96% of the total collagen in heart (1), are increased in the aged diabetic heart. Second, we explored the effects of the AGE cross-link breaker phenyl-4,5-dimethylthazolium chloride (ALT-711) to determine whether it improved function of the heart and also whether it reduced collagen in the heart. These goals are important because almost no information is available on the distribution of these collagen types either in the aged diabetic heart or, conversely, in their distribution following treatment with AGE cross-link breakers.

	METHODS

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Chronic Animal Model

Twelve healthy, male mongrel dogs, aged 9–12 yr and weighing 24–34 kg, were obtained from LBL Kennels (Reelsville, IN). The protocol was approved by the Institutional Animal Care Committee of New Jersey Medical School. The relative lack of coronary atherosclerosis in this species simplifies the consideration of variables affecting the myocardium (2). The animals were screened for diabetes before entering the study. Ages were obtained by documentation from the vendor, supplemented by eye, fur, and dental examination. Animals with evidence of pericardial or valvular disease by echocardiography were excluded. One animal died of an arrhythmia during biopsy during the second study, and one died of cardiac tamponade during surgery in the second study. For hemodynamics and other physiological parameters, the remaining 10 dogs were studied before diabetes and after the induction of diabetes, and then diabetics were studied after treatment with ALT-711, each serving as its own control with baseline echocardiographic studies of left ventricular (LV) function. After the initial hemodynamic measurement, the same mongrel dogs were studied again 5 mo after the induction of diabetes with alloxan monohydrate (25–35 mg/kg in sterile saline, administered intravenously for 2–3 doses at weekly intervals). Fasting blood sugar was measured at 1- to 2-day intervals until a stable elevation was obtained. Thereafter, blood was taken weekly for glucose determination (3). Glycosylated hemoglobin A_1c (Hb A_1c) was measured by affinity chromatography (3). Five animals were fed with the cross-link breaker ALT-711 (1 mg/kg) daily for 1 mo before the terminal study. After hemodynamic studies, the hearts of control, diabetic, and drug-treated (ALT-711) diabetic groups of animals were harvested and stored at –80°C for collagen analysis.

Hemodynamic Studies

Aged dogs were anesthetized with ketamine (5 mg/kg iv) and fentanyl (20 µg/kg iv) after induction with pentobarbital sodium, followed by fentanyl and ketamine drip at 0.7 µg · kg^–1 · min^–1 and 0.16 mg · kg^–1 · min^–1, respectively. A cuffed endotracheal tube was inserted, and ventilation was controlled with a Harvard respiration pump to maintain the arterial pH and PO₂ within physiological range. Under sterile conditions, a size 7-Fr micromanometer catheter (Millar Instruments, Houston, TX) was introduced into the proximal aorta via the carotid artery and connected with a Honeywell physiological recording system. LV end-diastolic and endsystolic volumes were measured by two-dimensional echocardiography (ATL Ultramark VI) with 3.5-MHz transducers and calculated using an area-length method with a cylinder-ellipsoid model: 5/6 of the cross-sectional area at the papillary muscle level times length from a LV long-axis view. LV ejection fraction (LVEF) was calculated as LV end-diastolic volume minus LV end-systolic volume divided by LV enddiastolic volume, expressed as a percentage (25). LV mass was calculated by subtracting the LV endocardial volume from the epicardial volume and multiplying the difference by a muscle density coefficient of 1.05. The endocardial and epicardial tracing was performed according to the convention of the American Society of Echocardiography. Aortic stiffness index (18) was calculated on the basis of the formula for a cylinder: = 127.32SP – DP/(d_max² – d_min²), recorded from a Millar catheter 2 cm from the aortic valve (where SP is systolic pressure, DP is diastolic pressure, and d is diameter). Systolic and diastolic dimensions of the ascending aorta were assessed by M-mode echocardiography.

Biochemical Studies

Dogs were killed and their hearts excised. LV endo- and epicardiums were quickly frozen in liquid nitrogen and stored at –80°C until used for biochemical measurements.

Collagen extraction. Collagen types I and III were extracted as described (4), with the following modification. Briefly, 500 mg of tissue were suspended in 8 ml of 50 mM Tris buffer (pH 7.4), 1 M NaCl, and 5 mM EDTA with protease inhibitor cocktail (Sigma) and homogenized using a Polytron homogenizer. The homogenate was centrifuged at 26,000 g, and the supernatant was discarded. The pellet was extracted with 0.5 M acetic acid for 24 h. This was followed by 0.5 M acetic acid containing pepsin (1 mg/ml) for 60 h at 4°C. The pepsin extraction was repeated for another 24 h, followed by a third pepsin extraction. Total collagen was precipitated from the pepsin extracts by adding NaCl to a 5% final concentration at 4°C and collected by centrifugation. Extracted collagen pellets were resolubilized in 0.5M Tris · HCl (pH 7.4) and used for the immunoblot analyses of collagen type I and type III.

Immunoblot analysis of collagen types I and III. Pepsin extract (6.4 mg equivalent wet wt tissue) was subjected to 8% SDS polyacrylamide gel electrophoresis, and proteins were then transferred to nitrocellulose membranes. Molecular weight markers and standard bovine collagen (Abcam, Cambridge, UK) were used as internal controls. The membranes were probed with rabbit polyclonal antibodies for collagen type I (1:5,000; Abcam) or collagen type III (1:5,000; Abcam) and with secondary anti-rabbit antibody (1:5,000; Amersham). The blots were developed using an enhanced chemiluminescence reagent kit (Perkin-Elmer). Relative densities were scanned, quantified, and expressed as arbitrary units.

Cross-linking by collagen solubility profile. To determine myocardial solubility, LV tissue samples (300 mg) were homogenized in 50 mM Tris (pH 7.5), 5 mM EDTA, protease inhibitors, and 20 mM NaF. The pellet was digested with 2.5 ml of 200 µg/ml pepsin in 0.5 M acetic acid at 37°C (6, 16) for 2 and 24 h. Collagen content was determined by measuring hydroxyproline content after 2 and 24 h of pepsin digestion and acid hydrolysis with 6 N HCl for 20 h at 110°C (26). Collagen solubility was calculated as the hydroxyproline content after 2 h of digestion as a percentage of the total collagen recovered after 24 h of pepsin digestion.

Statistical Analysis

Data are expressed as means ± SE. Comparison between two values was performed using Student's t-test. For multiple comparisons among different groups of data, significant differences were determined by the Bonferroni or Newman-Keuls methods. A P value of <0.05 was considered statistically significant. Because measurements presented were not obtained in all animals, n values for each parameter are listed in the text or figures.

	RESULTS

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Physiological Data

Blood glucose concentration of aging diabetic (Ag + DM) dogs was considerably higher than in Ag dogs but was not affected by the administration of ALT-711 in Ag + DM + ALT-711 dogs (Table 1). Hyperglycemia persisted throughout the study period and did not differ between the diabetic group and the diabetic group treated with ALT-711. Hb A_1c levels were increased more than twofold at each of the monthly determinations in Ag + DM vs. Ag groups (P < 0.05). Body weight did not differ among the experimental groups. Five months after the induction of DM, LV weight in hearts from Ag + DM dogs increased by 14% above that in Ag controls (P < 0.05). The increase in LV weight in Ag + DM hearts was reversed by ALT-711 (P < 0.05). Taken together, the data indicate that hyperglycemia induces an increase in LV mass of the aging dog, which can be reversed by ALT-711 treatment.

Hemodynamic Parameters

Five months after the induction of DM, heart rate did not differ among the experimental groups, but, as shown in Table 1, the Ag + DM group exhibited a 25% reduction in LVEF (P < 0.05), which was accounted for by a decrease in stroke volume (SV). SV was lower in the Ag + DM group by 28% (1.3 vs. 1.8 ml/kg in Ag group, P < 0.05). LVEF and SV in the Ag + DM dogs were restored to values measured in Ag dogs following 4 wk of treatment with ALT-711 (Table 1). Treatment of Ag + DM dogs with ALT-711 restored LVEF and SV to values measured in Ag dogs (P < 0.05). As shown in Table 1, aortic stiffness increased 1.7-fold (P < 0.05) after 5 mo of diabetes. The normalization of LVEF following ALT-711 treatment was accompanied by a 42% (P < 0.05) decrease in aortic stiffness (Table 1). Baseline LV end-diastolic volume did not differ among the experimental groups.

Collagen Types

To determine whether DM alters collagen types I and III in the aging heart, immunoblot analysis was performed on the pepsin-treated collagen extracts. As shown in Fig. 1A, collagen type I was increased (2-fold) in Ag + DM compared with Ag hearts (P < 0.05). ALT-711 reversed the upregulation in collagen I levels in Ag + DM hearts (P < 0.05). We next asked whether collagen III would exhibit a similar distribution pattern. Collagen III increased approximately three fold in the hearts of Ag + DM dogs compared with Ag hearts (P < 0.05). ALT-711 also reversed the upregulation of collagen III content in Ag + DM hearts (Fig. 1B). Taken together, DM upregulates collagen type I and III content in the Ag + DM myocardium. ALT-711 reverses DM-induced alterations in collagen type I and type III content in the Ag + DM heart.

View larger version (29K): [in this window] [in a new window]   Fig. 1. Collagen type I (A) and collagen type III protein levels (B) determined by immunoblot analysis in aging (Ag, open bar), aging + diabetes (Ag + DM, hatched bar), and aging + diabetes + ALT-711 (Ag + DM + ALT, filled bar)-treated animals (n = 5–7). Type I collagen and type III collagen were significantly increased in Ag + DM compared with Ag and significantly decreased in Ag + DM + ALT compared with Ag + DM. C: left ventricular collagen solubility studies show an increase in percent solubility in Ag + DM dogs following treatment with ALT-711 (n = 5–6). Values are expressed as means ± SE. *P < 0.05, different from Ag or Ag + DM + ALT different from Ag + DM.

Collagen Solubility

The percent solubility of myocardial LV collagen tended to fall with DM but increased significantly (P < 0.05) from 34 ± 4.9 to 51 ± 6.8% after treatment with ALT-711 (Fig. 1C).

	DISCUSSION

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DM is associated with an increased risk of cardiovascular disease (7, 12, 21). Increased intracellular AGE formation plays a critical role in the development of diabetic complications (19); conversely, inhibition of AGE formation can prevent the development of diabetic complications. AGE cross-links contribute to arterial stiffening in humans, supporting experimental studies performed in diabetic and nondiabetic animal models (2). Some investigations suggest that collagen cross-linking and turnover rate may be as important as the total amount of collagen found in the aged heart (17). Cross-linking among collagen molecules has the potential to increase the strength of the interstitium by covalently linking the fibrillar collagen molecules together (22, 24). ALT-711, an agent that reverses AGE cross-linking, improves arterial compliance and reduces arterial pulse pressure in older individuals with a stiffened vasculature (6, 14, 15, 29). AGEs covalently modify proteins by forming bonds with amino groups on other proteins, resulting in a matrix of cross-links. In the present study, we demonstrated that the AGE cross-link breaker ALT-711 reversed DM-induced increases in collagen of the aged diabetic heart.

Hyperglycemia dominates the pathophysiology and clinical course of DM. The Framingham Study has provided compelling evidence for the existence of a primary cardiomyopathy in DM (8, 9, 13). The goal of the present study was to test the hypothesis that the cross-link breaker ALT-711 would preserve pump function in the aged DM dog heart and reduce the increased levels of collagen in the aged DM heart. Investigations were performed in aged dogs with alloxan-induced DM. Five months after the induction of DM in aged dogs, LVEF, and LVSV were significantly impaired, and aortic stiffness was increased. These indexes of depressed pump function and decreased vascular compliance were reversed after 1 mo of treatment with the AGE cross-link breaker (ALT-711). We also demonstrated that both DM and aging increased collagen in the heart and that this process was reversed with the AGE cross-link breaker ALT-711, consistent with the hypothesis that decreased LV compliance in the diabetic heart is the result of increased extracellular matrix deposition (5). In further support, we found that the solubility of collagen increases in the hearts of aged diabetic dogs treated with ALT-711, which was also observed in young DM rats (6). It has also been proposed that incubation of AGE cross-linked collagen with ALT-711 in vitro restores matrix metalloproteinase digestibility of collagen (14), and evidence has been presented that AGE formation associated with DM reduces extracellular matrix degradation and angiogenesis (27).

In the present investigation, LV mass increased in the aged DM heart, which has been observed in aged DM humans (11, 23); furthermore, LV mass fell with ALT-711 treatment. This could also have contributed to the improved LV function obtained in the aged DM dogs treated with ALT-711.

Relatively little is known about the changes in distribution of subtypes of collagen in aging or DM, and virtually nothing is known about this in aged diabetic hearts. In the aging human heart, with the use of transmission electron microscopy, type I collagen fibers were shown to be increased in thickness and number (10). A major finding of the present investigation was that DM superimposed on aging increases both types I and III collagen, which accounts for 96% of total collagen in the heart, approximately two- to threefold. We found that ALT-711 decreased collagen type I and type III in aged DM hearts, indicating that cross-links may be important for increases in total amounts of types I and III collagen as well as for some of the hemodynamic alterations in aged dogs with DM. Taken together, the present study provides evidence for DM-induced alterations in collagen types I and III in the aged, large mammalian heart and for reversal of these alterations by the cross-link breaker ALT-711, which was associated with reversal of the adverse effects of DM on the function of the aged heart and aorta. It has also been proposed that incubation of AGE cross-linked collagen with ALT-711 in vitro restores matrix metalloproteinase digestibility of collagen (14), and evidence has been presented that AGE formation associated with DM reduces extracellular matrix degradation and angiogenesis (27).

In summary, the induction of DM in aging dogs induced LV systolic dysfunction, increased aortic stiffness, and increased collagen types I and III protein content. Here, we report that the AGE cross-link breaker ALT-711 reversed DM-induced myocardial collagen types I and III accumulation, aortic stiffness, LV dysfunction, and increased LV mass. These results support a causative role for collagen-linked glycosylation in the biochemical and hemodynamic alterations in the aging diabetic myocardium and aorta and that a collagen cross-link breaker could possibly provide therapeutic potential in the treatment of aging diabetic patients.

	DISCLOSURES

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This study was supported by American Diabetes Association Grant 700RA20 and by National Heart, Lung, and Blood Institute Grants HL-33107, HL-69020, and HL-59135. ALT-711 was a gift to T. Regan from Alteon, Inc., Ramsey, NJ.

	FOOTNOTES

 

Address for other correspondence: D. E. Vatner, Cardiovascular Research Institute, Dept. of Cell Biology and Molecular Medicine, UMDNJ-New Jersey Medical School, PO Box 1709, 185 S. Orange Ave. (MSB G-609), Newark, NJ 07101-1709 (E-mail: vatnerdo{at}umdnj.edu).

Address for reprint requests: A. Malhotra, Div. of Nephrology and Hypertension, Dept. of Medicine, UMDNJ-New Jersey Medical School, PO Box 1709, 185 S. Orange Ave. (MSB I-524), Newark, NJ 07101-1709 (E-mail: malhotas{at}umdnj.edu).

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Deceased 20 October 2001.

	REFERENCES

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1. Annoni G, Luvara G, Arosio B, Gagliano N, Fiordaliso F, Santambrogio D, Jeremic G, Mircoli L, Latini R, Vergani C, and Masson S. Age-dependent expression of fibrosis-related genes and collagen deposition in the rat myocardium. Mech Ageing Dev 101: 57–72, 1998.[Web of Science][Medline]
2. Asif M, Egan J, Vasan S, Jyothirmayi GN, Masurekar MR, Lopez S, Williams C, Torres RL, Wagle D, Ulrich P, Cerami A, Brines M, and Regan TJ. An advanced glycation endproduct cross-link breaker can reverse age-related increases in myocardial stiffness. Proc Natl Acad Sci USA 97: 2809–2813, 2000.[Abstract/Free Full Text]
3. Avendano GF, Agarwal RK, Bashey RI, Lyons MM, Soni BJ, Jyothirmayi GN, and Regan TJ. Effects of glucose intolerance on myocardial function and collagen-linked glycation. Diabetes 48: 1443–1447, 1999.[Abstract]
4. Bashey RI, Cox R, McCann J, and Jimenez SA. Changes in collagen biosynthesis, types, and mechanics of aorta in hypertensive rats. J Lab Clin Med 113: 604–611, 1989.[Web of Science][Medline]
5. Burgess ML, McCrea JC, and Hedrick HL. Age-associated changes in cardiac matrix and integrins. Mech Ageing Dev 122: 1739–1756, 2001.[Web of Science][Medline]
6. Candido R, Forbes JM, Thomas MC, Thallas V, Dean RG, Burns WC, Tikellis C, Ritchie RH, Twigg SM, Cooper ME, and Burrell LM. A breaker of advanced glycation end products attenuates diabetes-induced myocardial structural changes. Circ Res 92: 785–792, 2003.[Abstract/Free Full Text]
7. Coughlin SS, Pearle DL, Baughman KL, Wasserman A, and Tefft MC. Diabetes mellitus and risk of idiopathic dilated cardiomyopathy. The Washington DC Dilated Cardiomyopathy Study. Ann Epidemiol 4: 67–74, 1994.[Medline]
8. Galderisi M, Anderson KM, Wilson PW, and Levy D. Echocardiographic evidence for the existence of a distinct diabetic cardiomyopathy (the Framingham Heart Study). Am J Cardiol 68: 85–89, 1991.[Web of Science][Medline]
9. Garcia MJ, McNamara PM, Gordon T, and Kannel WB. Morbidity and mortality in diabetics in the Framingham population. Sixteen year follow-up study. Diabetes 23: 105–111, 1974.[Web of Science][Medline]
10. Gazoti Debessa CR, Mesiano Maifrino LB, and Rodrigues de Souza R. Age related changes of the collagen network of the human heart. Mech Ageing Dev 122: 1049–1058, 2001.[Web of Science][Medline]
11. Ilercil A, Devereux RB, Roman MJ, Paranicas M, O'Grady MJ, Welty TK, Robbins DC, Fabsitz RR, Howard BV, and Lee ET. Relationship of impaired glucose tolerance to left ventricular structure and function: the Strong Heart Study. Am Heart J 141: 992–998, 2001.[Web of Science][Medline]
12. Kannel WB, Hjortland M, and Castelli WP. Role of diabetes in congestive heart failure: the Framingham study. Am J Cardiol 34: 29–34, 1974.[Web of Science][Medline]
13. Kannel WB and McGee DL. Diabetes and cardiovascular disease. The Framingham study. JAMA 241: 2035–2038, 1979.[Abstract/Free Full Text]
14. Kass DA. Getting better without AGE: new insights into the diabetic heart. Circ Res 92: 704–706, 2003.[Free Full Text]
15. Kass DA, Shapiro EP, Kawaguchi M, Capriotti AR, Scuteri A, deGroof RC, and Lakatta EG. Improved arterial compliance by a novel advanced glycation end-product crosslink breaker. Circulation 104: 1464–1470, 2001.[Abstract/Free Full Text]
16. Kochakian M, Manjula BN, and Egan JJ. Chronic dosing with aminoguanidine and novel advanced glycosylation end product-formation inhibitors ameliorates cross-linking of tail tendon collagen in STZ-induced diabetic rats. Diabetes 45: 1694–1700, 1996.[Abstract]
17. Mays PK, McAnulty RJ, Campa JS, and Laurent GJ. Age-related changes in collagen synthesis and degradation in rat tissues. Importance of degradation of newly synthesized collagen in regulating collagen production. Biochem J 276: 307–313, 1991.
18. Meaney E, Soltero E, Samaniego V, Alva F, Moguel R, Vela A, and Gonzalez V. Vascular dynamics in isolated systolic arterial hypertension. Clin Cardiol 18: 721–725, 1995.[Web of Science][Medline]
19. Nishikawa T, Edelstein D, Du XL, Yamagishi S, Matsumura T, Kaneda Y, Yorek MA, Beebe D, Oates PJ, Hammes HP, Giardino I, and Brownlee M. Normalizing mitochondrial superoxide production blocks three pathways of hyperglycaemic damage. Nature 404: 787–790, 2000.[Medline]
20. Paul RG and Bailey AJ. Glycation of collagen: the basis of its central role in the late complications of ageing and diabetes. Int J Biochem Cell Biol 28: 1297–1310, 1996.[Web of Science][Medline]
21. Regan TJ, Lyons MM, Ahmed SS, Levinson GE, Oldewurtel HA, Ahmad MR, and Haider B. Evidence for cardiomyopathy in familial diabetes mellitus. J Clin Invest 60: 884–899, 1977.[Medline]
22. Reiser K, McCormick RJ, and Rucker RB. Enzymatic and nonenzymatic cross-linking of collagen and elastin. FASEB J 6: 2439–2449, 1992.[Abstract]
23. Rutter MK, Parise H, Benjamin EJ, Levy D, Larson MG, Meigs JB, Nesto RW, Wilson PW, and Vasan RS. Impact of glucose intolerance and insulin resistance on cardiac structure and function: sex-related differences in the Framingham Heart Study. Circulation 107: 448–454, 2003.[Abstract/Free Full Text]
24. Sajithlal GB, Chithra P, and Chandrakasan G. Advanced glycation end products induce crosslinking of collagen in vitro. Biochim Biophys Acta 1407: 215–224, 1998.[Medline]
25. Schiller NB, Shah PM, Crawford M, DeMaria A, Devereux R, Feigenbaum H, Gutgesell H, Reichek N, Sahn D, Schnittger I, and et al. Recommendations for quantitation of the left ventricle by two-dimensional echocardiography American Society of Echocardiography Committee on Standards, Subcommittee on Quantitation of Two-Dimensional Echocardiograms. JAm Soc Echocardiogr 2: 358–367, 1989.
26. Stegemann H and Stalder K. Determination of hydroxyproline. Clin Chim Acta 18: 267–273, 1967.[Web of Science][Medline]
27. Tamarat R, Silvestre JS, Huijberts M, Benessiano J, Ebrahimian TG, Duriez M, Wautier MP, Wautier JL, and Levy BI. Blockade of advanced glycation end-product formation restores ischemia-induced angiogenesis in diabetic mice. Proc Natl Acad Sci USA 100: 8555–8560, 2003.[Abstract/Free Full Text]
28. Thomas DP, McCormick RJ, Zimmerman SD, Vadlamudi RK, and Gosselin LE. Aging- and training-induced alterations in collagen characteristics of rat left ventricle and papillary muscle. Am J Physiol Heart Circ Physiol 263: H778–H783, 1992.[Abstract/Free Full Text]
29. Vaitkevicius PV, Lane M, Spurgeon H, Ingram DK, Roth GS, Egan JJ, Vasan S, Wagle DR, Ulrich P, Brines M, Wuerth JP, Cerami A, and Lakatta EG. A cross-link breaker has sustained effects on arterial and ventricular properties in older rhesus monkeys. Proc Natl Acad Sci USA 98: 1171–1175, 2001.[Abstract/Free Full Text]

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