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Early and late postnatal myocardial and vascular changes in a protein restriction rat model of intrauterine growth restriction.

Menendez-Castro C, Fahlbusch F, Cordasic N, Amann K, Münzel K, Plank C, Wachtveitl R, Rascher W, Hilgers KF, Hartner A - PLoS ONE (2011)

Bottom Line: The offspring was reduced to six males per litter.At day 70 the expression of osteopontin was induced 7.2-fold.A 3- to 7-fold increase in the expression of the profibrotic cytokines TGF-β and CTGF as well as of microfibrillar matrix molecules was observed.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics and Adolescent Medicine, University of Erlangen-Nürnberg, Erlangen, Germany. carlos.menendez-castro@uk-erlangen.de

ABSTRACT
Intrauterine growth restriction (IUGR) is a risk factor for cardiovascular disease in later life. Early structural and functional changes in the cardiovascular system after IUGR may contribute to its pathogenesis. We tested the hypothesis that IUGR leads to primary myocardial and vascular alterations before the onset of hypertension. A rat IUGR model of maternal protein restriction during gestation was used. Dams were fed low protein (LP; casein 8.4%) or isocaloric normal protein diet (NP; casein 17.2%). The offspring was reduced to six males per litter. Immunohistochemical and real-time PCR analyses were performed in myocardial and vascular tissue of neonates and animals at day 70 of life. In the aortas of newborn IUGR rats expression of connective tissue growth factor (CTGF) was induced 3.2-fold. At day 70 of life, the expression of collagen I was increased 5.6-fold in aortas of IUGR rats. In the hearts of neonate IUGR rats, cell proliferation was more prominent compared to controls. At day 70 the expression of osteopontin was induced 7.2-fold. A 3- to 7-fold increase in the expression of the profibrotic cytokines TGF-β and CTGF as well as of microfibrillar matrix molecules was observed. The myocardial expression and deposition of collagens was more prominent in IUGR animals compared to controls at day 70. In the low-protein diet model, IUGR leads to changes in the expression patterns of profibrotic genes and discrete structural abnormalities of vessels and hearts in adolescence, but, with the exception of CTGF, not as early as at the time of birth. Invasive and non-invasive blood pressure measurements confirmed that IUGR rats were normotensive at the time point investigated and that the changes observed occurred independently of an increased blood pressure. Hence, altered matrix composition of the vascular wall and the myocardium may predispose IUGR animals to cardiovascular disease later in life.

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Myocardial deposition of collagen IV.Evaluation of the percentage of positive immunostaining for collagen IV (coll IV) in myocardial tissue of (A) neonatal control rats and neonatal rats with intrauterine growth restriction (neo) with representative photomicrographs; and in myocardial tissue of (B) control rats and rats with intrauterine growth restriction at day 70 of life (d70) with representative photomicrographs. NP, control rats; LP, rats with intrauterine growth restriction. Data are means ± sem.
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pone-0020369-g006: Myocardial deposition of collagen IV.Evaluation of the percentage of positive immunostaining for collagen IV (coll IV) in myocardial tissue of (A) neonatal control rats and neonatal rats with intrauterine growth restriction (neo) with representative photomicrographs; and in myocardial tissue of (B) control rats and rats with intrauterine growth restriction at day 70 of life (d70) with representative photomicrographs. NP, control rats; LP, rats with intrauterine growth restriction. Data are means ± sem.

Mentions: The expression of two profibrotic cytokines, TGF-β and CTGF, was studied. While TGF-β expression was the same in neonate aortas of LP and NP rats (table 4), CTGF mRNA expression was significantly higher in neonate aortas of LP rats compared to NP rats (table 4). This was also reflected on the protein level: Western blot analysis revealed increased CTGF protein expression in neonate aortas of LP rats compared to NP rats (figure 4A+B). At day 70 of life, the aortal expression of TGF-β was still similar in both experimental groups (table 4), while due to a high variability in LP rats the expression of CTGF only revealed a tendency to be increased in LP (p = 0.06; table 4). In contrast to the findings in aortas, similar neonatal changes were not observed in myocardial tissue of LP rats: In the hearts of neonate rats, no differences in the expression levels of the profibrotic cytokines TGF-β and CTGF were detected between LP and NP (table 4). At day 70 of life, however, the myocardial expression of both TGF-β and CTGF was augmented in LP (table 4). Subsequently, we evaluated the expression of several matrix molecules. Measurements of the expression levels of the microfibrillar matrix proteins LTBP-1, fibrillin-1 and elastin did not reveal any significant differences in aortas of neonate NP and LP as well as in NP and LP at day 70 of life. In myocardial tissue of neonate NP and LP rats, the expression of microfibrillar matrix proteins did not vary significantly (p = 0.17 for LTBP; p = 0.10 for fibrillin-1 and p = 0.28 for elastin; table 4). At day 70 of life, however, the expression of microfibrillar matrix proteins was 3 to 5-fold increased in the myocardium of LP rats (figure 4). Evaluation of the expression patterns of fibronectin revealed no differences in the aorta of newborn rats, but a tendency to more aortal fibronectin expression at day 70 of life (p = 0.052; table 4). In the hearts of newborn LP rats, no increase in fibronectin expression was observed, but at day 70 of life fibronectin expression was augmented in the hearts of LP rats (table 4). Collagen I and IV expression and deposition was not different in the aortas of neonate NP and LP rats (table 4). At day 70 of life, an increase in collagen I expression and a tendency to more collagen I deposition (p = 0.07) and more collagen IV deposition was observed in LP rats (table 4). Moreover, myocardial collagen I and IV expression and deposition, although not altered in neonate LP rats, were all increased at day 70 of life (table 4, figures 5 and 6). Finally, evaluation of the aortal expression levels of two regulators of matrix turnover, TIMP-1 and TIMP-2 did not reveal any significant differences in neonate NP and LP rats nor at day 70 of life (table 4). At day 70 of life, only a tendency towards an increased expression of TIMP-2 was observed in aortas of LP animals (p = 0.053; table 4). In the hearts of LP rats, solely the expression of TIMP-2 was significantly higher than of NP rats at day 70 of life (figure 4), while the expression of TIMP-1 merely revealed a trend to be increased in the hearts of LP rats at day 70 of life (p = 0.17) due to a high variability in expression levels (table 4).


Early and late postnatal myocardial and vascular changes in a protein restriction rat model of intrauterine growth restriction.

Menendez-Castro C, Fahlbusch F, Cordasic N, Amann K, Münzel K, Plank C, Wachtveitl R, Rascher W, Hilgers KF, Hartner A - PLoS ONE (2011)

Myocardial deposition of collagen IV.Evaluation of the percentage of positive immunostaining for collagen IV (coll IV) in myocardial tissue of (A) neonatal control rats and neonatal rats with intrauterine growth restriction (neo) with representative photomicrographs; and in myocardial tissue of (B) control rats and rats with intrauterine growth restriction at day 70 of life (d70) with representative photomicrographs. NP, control rats; LP, rats with intrauterine growth restriction. Data are means ± sem.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3105022&req=5

pone-0020369-g006: Myocardial deposition of collagen IV.Evaluation of the percentage of positive immunostaining for collagen IV (coll IV) in myocardial tissue of (A) neonatal control rats and neonatal rats with intrauterine growth restriction (neo) with representative photomicrographs; and in myocardial tissue of (B) control rats and rats with intrauterine growth restriction at day 70 of life (d70) with representative photomicrographs. NP, control rats; LP, rats with intrauterine growth restriction. Data are means ± sem.
Mentions: The expression of two profibrotic cytokines, TGF-β and CTGF, was studied. While TGF-β expression was the same in neonate aortas of LP and NP rats (table 4), CTGF mRNA expression was significantly higher in neonate aortas of LP rats compared to NP rats (table 4). This was also reflected on the protein level: Western blot analysis revealed increased CTGF protein expression in neonate aortas of LP rats compared to NP rats (figure 4A+B). At day 70 of life, the aortal expression of TGF-β was still similar in both experimental groups (table 4), while due to a high variability in LP rats the expression of CTGF only revealed a tendency to be increased in LP (p = 0.06; table 4). In contrast to the findings in aortas, similar neonatal changes were not observed in myocardial tissue of LP rats: In the hearts of neonate rats, no differences in the expression levels of the profibrotic cytokines TGF-β and CTGF were detected between LP and NP (table 4). At day 70 of life, however, the myocardial expression of both TGF-β and CTGF was augmented in LP (table 4). Subsequently, we evaluated the expression of several matrix molecules. Measurements of the expression levels of the microfibrillar matrix proteins LTBP-1, fibrillin-1 and elastin did not reveal any significant differences in aortas of neonate NP and LP as well as in NP and LP at day 70 of life. In myocardial tissue of neonate NP and LP rats, the expression of microfibrillar matrix proteins did not vary significantly (p = 0.17 for LTBP; p = 0.10 for fibrillin-1 and p = 0.28 for elastin; table 4). At day 70 of life, however, the expression of microfibrillar matrix proteins was 3 to 5-fold increased in the myocardium of LP rats (figure 4). Evaluation of the expression patterns of fibronectin revealed no differences in the aorta of newborn rats, but a tendency to more aortal fibronectin expression at day 70 of life (p = 0.052; table 4). In the hearts of newborn LP rats, no increase in fibronectin expression was observed, but at day 70 of life fibronectin expression was augmented in the hearts of LP rats (table 4). Collagen I and IV expression and deposition was not different in the aortas of neonate NP and LP rats (table 4). At day 70 of life, an increase in collagen I expression and a tendency to more collagen I deposition (p = 0.07) and more collagen IV deposition was observed in LP rats (table 4). Moreover, myocardial collagen I and IV expression and deposition, although not altered in neonate LP rats, were all increased at day 70 of life (table 4, figures 5 and 6). Finally, evaluation of the aortal expression levels of two regulators of matrix turnover, TIMP-1 and TIMP-2 did not reveal any significant differences in neonate NP and LP rats nor at day 70 of life (table 4). At day 70 of life, only a tendency towards an increased expression of TIMP-2 was observed in aortas of LP animals (p = 0.053; table 4). In the hearts of LP rats, solely the expression of TIMP-2 was significantly higher than of NP rats at day 70 of life (figure 4), while the expression of TIMP-1 merely revealed a trend to be increased in the hearts of LP rats at day 70 of life (p = 0.17) due to a high variability in expression levels (table 4).

Bottom Line: The offspring was reduced to six males per litter.At day 70 the expression of osteopontin was induced 7.2-fold.A 3- to 7-fold increase in the expression of the profibrotic cytokines TGF-β and CTGF as well as of microfibrillar matrix molecules was observed.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics and Adolescent Medicine, University of Erlangen-Nürnberg, Erlangen, Germany. carlos.menendez-castro@uk-erlangen.de

ABSTRACT
Intrauterine growth restriction (IUGR) is a risk factor for cardiovascular disease in later life. Early structural and functional changes in the cardiovascular system after IUGR may contribute to its pathogenesis. We tested the hypothesis that IUGR leads to primary myocardial and vascular alterations before the onset of hypertension. A rat IUGR model of maternal protein restriction during gestation was used. Dams were fed low protein (LP; casein 8.4%) or isocaloric normal protein diet (NP; casein 17.2%). The offspring was reduced to six males per litter. Immunohistochemical and real-time PCR analyses were performed in myocardial and vascular tissue of neonates and animals at day 70 of life. In the aortas of newborn IUGR rats expression of connective tissue growth factor (CTGF) was induced 3.2-fold. At day 70 of life, the expression of collagen I was increased 5.6-fold in aortas of IUGR rats. In the hearts of neonate IUGR rats, cell proliferation was more prominent compared to controls. At day 70 the expression of osteopontin was induced 7.2-fold. A 3- to 7-fold increase in the expression of the profibrotic cytokines TGF-β and CTGF as well as of microfibrillar matrix molecules was observed. The myocardial expression and deposition of collagens was more prominent in IUGR animals compared to controls at day 70. In the low-protein diet model, IUGR leads to changes in the expression patterns of profibrotic genes and discrete structural abnormalities of vessels and hearts in adolescence, but, with the exception of CTGF, not as early as at the time of birth. Invasive and non-invasive blood pressure measurements confirmed that IUGR rats were normotensive at the time point investigated and that the changes observed occurred independently of an increased blood pressure. Hence, altered matrix composition of the vascular wall and the myocardium may predispose IUGR animals to cardiovascular disease later in life.

Show MeSH
Related in: MedlinePlus