scholarly journals Early sequence of cardiac adaptations and growth factor formation in pressure- and volume-overload hypertrophy

2000 ◽  
Vol 279 (3) ◽  
pp. H976-H985 ◽  
Author(s):  
Pietro Amedeo Modesti ◽  
Simone Vanni ◽  
Iacopo Bertolozzi ◽  
Ilaria Cecioni ◽  
Gianluca Polidori ◽  
...  
Keyword(s):  
Growth Factor ◽  
Myocardial Contractility ◽  
Pressure Overload ◽  
Volume Overload ◽  
Aortic Banding ◽  
Peptide Formation ◽  
Cardiac Adaptation ◽  
Igf I ◽  
Hemodynamic Measurements

To investigate the time sequence of cardiac growth factor formation, echocardiographic and hemodynamic measurements were performed at scheduled times, and mRNAs for angiotensinogen, prepro-endothelin-1 (ppET-1), and insulin-like growth factor I (IGF-I) were quantified with RT-PCR and localized with in situ hybridization in pigs (fluothane anesthesia) by use of pressure or volume overload (aortic banding and aorta-cava fistula, respectively). Relative peptide formation was also measured by radioimmunoassay. In pressure overload, angiotensinogen and ppET-1 mRNA overexpression on myocytes (13 times vs. sham at 3 h and 112 times at 6 h, respectively) was followed by recovery (12 h) of initially decreased (0.5–6 h) myocardial contractility. In volume overload, contractility was not decreased, the angiotensinogen gene was slightly upregulated at 6 h (6.7 times), and ppET-1 was not overexpressed. IGF-I mRNA was overexpressed on myocytes (at 24 h) in both volume and pressure overload (14 times and 37 times, respectively). In the latter setting, a second ppET-1 overexpression was detectable on myocytes at 7 days. In conclusion, acute cardiac adaptation responses involve different growth factor activation over time in pressure versus volume overload; growth factors initially support myocardial contractility and thereafter induce myocardial hypertrophy.

scholarly journals Role of the cytoskeleton in the development of a hypofibrotic cardiac fibroblast phenotype in volume overload heart failure

2019 ◽  
Vol 316 (3) ◽  
pp. H596-H608 ◽  
Author(s):  
Rachel C. Childers ◽  
Ian Sunyecz ◽  
T. Aaron West ◽  
Mary J. Cismowski ◽  
Pamela A. Lucchesi ◽  
...  
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Smooth Muscle Actin ◽  
Pressure Overload ◽  
Volume Overload ◽  
Transforming Growth Factor Β ◽  
Collagen Type I ◽  
Tissue Growth ◽  
Type I

Hemodynamic load regulates cardiac remodeling. In contrast to pressure overload (increased afterload), hearts subjected to volume overload (VO; preload) undergo a distinct pattern of eccentric remodeling, chamber dilation, and decreased extracellular matrix content. Critical profibrotic roles of cardiac fibroblasts (CFs) in postinfarct remodeling and in response to pressure overload have been well established. Little is known about the CF phenotype in response to VO. The present study characterized the phenotype of primary cultures of CFs isolated from hearts subjected to 4 wk of VO induced by an aortocaval fistula. Compared with CFs isolated from sham hearts, VO CFs displayed a “hypofibrotic” phenotype, characterized by a ~50% decrease in the profibrotic phenotypic markers α-smooth muscle actin, connective tissue growth factor, and collagen type I, despite increased levels of profibrotic transforming growth factor-β1 and an intact canonical transforming growth factor-β signaling pathway. Actin filament dynamics were characterized, which regulate the CF phenotype in response to biomechanical signals. Actin polymerization was determined by the relative amounts of G-actin monomers versus F-actin. Compared with sham CFs, VO CFs displayed ~78% less F-actin and an increased G-actin-to-F-actin ratio (G/F ratio). In sham CFs, treatment with the Rho kinase inhibitor Y-27632 to increase the G/F ratio resulted in recapitulation of the hypofibrotic CF phenotype observed in VO CFs. Conversely, treatment of VO CFs with jasplakinolide to decrease the G/F ratio restored a more profibrotic response (>2.5-fold increase in α-smooth muscle actin, connective tissue growth factor, and collagen type I). NEW & NOTEWORTHY The present study is the first to describe a “hypofibrotic” phenotype of cardiac fibroblasts isolated from a volume overload model. Our results suggest that biomechanical regulation of actin microfilament stability and assembly is a critical mediator of cardiac fibroblast phenotypic modulation.

Endocrine control of the distribution of basic fibroblast growth factor, insulin-like growth factor-I and transforming growth factor-β1 mRNAs in adult rat adrenals using non-radioactive in situ hybridization

1995 ◽  
Vol 144 (2) ◽  
pp. 379-387 ◽  
Author(s):  
M M Ho ◽  
G P Vinson
Keyword(s):  
Growth Factor ◽  
Adrenal Cortex ◽  
Transforming Growth Factor ◽  
Zona Glomerulosa ◽  
Dietary Sodium ◽  
Zona Fasciculata ◽  
Sodium Restriction ◽  
Igf I ◽  
Rat Adrenals

Abstract This study located the particular cell types involved in the synthesis of growth factors in adult female rat adrenal glands. Non-isotopic in situ hybridization was used and the cellular localizations of the mRNAs of basic fibroblast growth factor (bFGF), IGF-I, and transforming growth factor-β1 (TGF-β1) were studied in adrenals from control animals and from those treated with ACTH or subjected to dietary sodium restriction. The adrenal medulla was the richest source of both bFGF and IGF-1 mRNA in both control and experimental rat adrenals. In the cortex, bFGF and IGF-I mRNAs were found mainly in the zona fasciculata in control animals, although some transcription was also detected in the zona reticularis and zona glomerulosa. Both ACTH and sodium restriction activated bFGF and IGF-I gene expression in the zona glomerulosa. Since cellular proliferation and differentiation occur primarily in the outer cortex, the data are consistent with the view that bFGF and IGF-I act as an autocrine/paracrine mitogen and differentiation regulator respectively in the rat adrenal cortex. Very small amounts of TGF-β1 mRNA were detected, predominantly in the zona fasciculata of control rats. There were no observable differences in amounts and localization of TGF-β1 mRNA between the adrenals of control rats and those treated with ACTH for 1 day. TGF-β1 mRNA was very weak or undetectable in the adrenals from rats treated with ACTH for three and five days or from sodium-restricted rats. Although TGF-β1 immunoreactive protein has been shown to be present in the zonae fasciculata and reticularis and to modulate negatively the steroidogenic activities in the adrenal cortex of other species, its gene is not actively expressed in rat adrenals. The present results showed that ACTH administration or dietary sodium restriction, both important adrenal mitogens in vivo, significantly altered the spatial patterns of the distribution of bFGF and IGF-I mRNAs and also increased the amount of bFGF mRNA in the adrenal cortex. This suggests that growth and differentiation of the adrenal cortex are partly mediated by bFGF and IGF-I. Journal of Endocrinology (1995) 144, 379–387

Minoxidil accelerates heart failure development in rats with ascending aortic constriction

1998 ◽  
Vol 76 (6) ◽  
pp. 613-620 ◽  
Author(s):  
Marian Turcani ◽  
Ruthard Jacob
Keyword(s):  
Heart Failure ◽  
Myocardial Contractility ◽  
Pressure Overload ◽  
Volume Overload ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Aortic Constriction ◽  
Lung Weight ◽  
Eccentric Hypertrophy ◽  
Hemodynamic Overload

To test the ability of the heart to express characteristic geometric features of concentric and eccentric hypertrophy concurrently, constriction of the ascending aorta was performed in 4-week-old rats. Simultaneously, these rats were treated with an arteriolar dilator minoxidil. An examination 6 weeks after induction of the hemodynamic overload revealed no signs of congestion in systemic or pulmonary circulation in rats with aortic constriction or minoxidil-treated sham-operated rats. The magnitude of hemodynamic overload caused by aortic constriction or minoxidil treatment could be considered as equivalent, because the same enlargement of left ventricular pressure-volume area was necessary to compensate for either pressure or volume overload. Myocardial contractility decreased in rats with aortic constriction, and the compensation was achieved wholly by the marked concentric hypertrophy. Volume overload in minoxidil-treated rats was compensated partially by the eccentric hypertrophy and partially by the increased myocardial contractility. In contrast, increased lung weight and pleural effusion were found in all minoxidil-treated rats with aortic constriction. Unfavorable changes in left ventricular mass and geometry, relatively high chamber stiffness, and depressed ventricular and myocardial function were responsible for the massive pulmonary congestion.Key words: cardiac hypertrophy, heart failure, pressure overload, volume overload, minoxidil.

Fiber orientation in hypertrophied canine left ventricle

1979 ◽  
Vol 236 (3) ◽  
pp. H487-H493 ◽  
Author(s):  
T. E. Carew ◽  
J. W. Covell
Keyword(s):  
Left Ventricle ◽  
Aortic Stenosis ◽  
Arteriovenous Fistula ◽  
Fiber Orientation ◽  
Diastolic Pressure ◽  
Pressure Overload ◽  
Volume Overload ◽  
Maximum Diameter ◽  
Myocardial Fiber

Myocardial fiber orientation was examined in transmural specimens obtained at the maximum diameter of the left ventricle from five dogs with pressure-overload hypertrophy produced by aortic stenosis, six dogs with volume-overload hypertrophy due to an arteriovenous fistula, and six exercise-hypertrophied greyhounds trained for racing. Hearts arrested in diastole were fixed in situ while the operating end-diastolic pressure was maintained. Fiber orientation changed smoothly from about +60 degrees (with respect to the equator) at the endocardium to about -69 degrees at the epicardium. The majority of fibers near the midwall were oriented circumferentially. These findings are quite similar to those previously reported for normal dogs. In comparison to normals, the left ventricles from dogs with pressure-overload had an increase in longitudinally oriented fibers, i.e. fiber angles between -67.5 degrees and -90 degrees and between +67.5 degrees and +90 degrees; these fibers comprised 10.4 +/- 1.8% of the total fibers in dogs with aortic stenosis vs. 2.9 +/- 1.8% of total fibers in normal dogs (P less than 0.001). Neither the dogs with volume-overload hypertrophy nor exercise-trained animals were significantly different from normals.

In situ mitochondrial function in volume overload- and pressure overload-induced cardiac hypertrophy in rats

1995 ◽  
Vol 90 (4) ◽  
pp. 305-313 ◽  
Author(s):  
Mong Hung Bui ◽  
R. Janati-Idrissi ◽  
B. Besson ◽  
M. Laplace
Keyword(s):  
Cardiac Hypertrophy ◽  
Mitochondrial Function ◽  
Pressure Overload ◽  
Volume Overload

Regulation by GH of insulin-like growth factor-I mRNA expression in rat epiphyseal growth plate as studied with in-situ hybridization

1990 ◽  
Vol 125 (1) ◽  
pp. 67-NP ◽  
Author(s):  
A. Nilsson ◽  
B. Carlsson ◽  
J. Isgaard ◽  
O. G. P. Isaksson ◽  
L. Rymo
Keyword(s):  
In Situ Hybridization ◽  
Growth Factor ◽  
Growth Plate ◽  
Hybridization Signal ◽  
Insulin Like Growth Factor ◽  
Epiphyseal Growth Plate ◽  
Factor I ◽  
Igf I ◽  
Old Rats

ABSTRACT Expression of insulin-like growth factor I (IGF-I) mRNA and its dependence on GH was studied in rat epiphyseal growth plate by in-situ hybridization. Methodological aspects of the technique were first evaluated on fixed sagittal cryosections from 28-day-old rat epiphyseal growth plates to ascertain specific hybridization. In-situ hybridization was compared on sections from 10- and 28-day-old rats and the GH-dependence was studied in 35-day-old hypophysectomized rats. Expression of IGF-I mRNA was apparent in chondrocytes of the proliferative, hypertrophic and early degenerative zones of the growth plate of 28-day-old rats. The epiphyseal growth plate from 10-day-old rats showed a weak hybridization signal compared with 28-day-old rats. In contrast, the mesenchymal cells of the periosteum of 10-day-old rats showed a rather strong hybridization signal. Hypophysectomy resulted in a reduction in hybridization signal and cell number of the growth plate compared with 35-day-old age-matched normal rats. GH-Replacement therapy (200 μg human GH s.c. every 4 h for 24 h) resulted in partially restored expression of IGF-I mRNA. The present study has shown that the IGF-I gene is expressed in the rat epiphyseal growth plate chondrocytes and that the expression is dependent on GH. The results support a paracrine/autocrine role of IGF-I for the expression of the stimulatory effect of GH on longitudinal bone growth. Journal of Endocrinology (1990) 125, 67–74

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