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Aorta remodeling responses to distinct atherogenic stimuli: hypertension, hypercholesterolemia and turbulent flow/low wall shear stress.

Prado CM, Rossi MA - Open Cardiovasc Med J (2008)

Bottom Line: This review is based on recently published data from our laboratory.We investigated the role of hypertension and laminar flow, hypercholesterolemia and laminar flow and turbulent blood flow/low wall shear stress, and turbulent blood flow/low wall shear stress associated with hypercholesterolemia on aorta remodeling of rats feeding normal diet or hypercholesterolemic diet.Our findings suggest that increased circumferential wall tension due to hypertension plays a key role in the remodeling through biomechanical effects on oxidative stress and increased TGF-beta expression; the remodeling observed in the presence of hypercholesterolemia could be initiated by oxidative stress that is involved in several processes of atherogenesis and this remodeling is more pronounced in the presence of turbulent blood flow/low wall shear stress.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, S.P., Brazil.

ABSTRACT
This review is based on recently published data from our laboratory. We investigated the role of hypertension and laminar flow, hypercholesterolemia and laminar flow and turbulent blood flow/low wall shear stress, and turbulent blood flow/low wall shear stress associated with hypercholesterolemia on aorta remodeling of rats feeding normal diet or hypercholesterolemic diet. Our findings suggest that increased circumferential wall tension due to hypertension plays a key role in the remodeling through biomechanical effects on oxidative stress and increased TGF-beta expression; the remodeling observed in the presence of hypercholesterolemia could be initiated by oxidative stress that is involved in several processes of atherogenesis and this remodeling is more pronounced in the presence of turbulent blood flow/low wall shear stress.

No MeSH data available.


Related in: MedlinePlus

Transmission electron microscopy. Representative aspects of the prestenotic (A), poststenotic (B), sham-operated+HD and prestenotic+HD (C) and poststenotic+HD (D) segments. Panel A. The intima is thickened. The endothelial cells are heterogeneous, most of them with convoluted nuclei and cytoplasmic contours. Focal accumulation of smooth muscle cells could be seen in the expanded intimal layer. Migration of smooth muscle cells from the media into the intima (* ) through the fenestras of the internal elastic lamina can be also seen. Panel B. Marked intimal thickening composed of great number of smooth muscle cells surrounded by basement membrane-like material and collagen and elastic fibers can be seen. Migration of smooth muscle cells from the media into the intima (* ) is shown. Panel C. Represen-tative view of the small flat lesions corresponding to fatty streaks characterized by a few vacuolated mononuclear and smooth muscle cells accumulation. Panel D. Representative view of the poststenotic raised incipient atherosclerotic lesions composed of mononuclear and smooth muscle cells, many of them vacuolated, surrounded by extracellular matrix. End, endothelial cell; iel, internal elastic lamina; smc, smooth muscle cell; mc, mononuclear cell; * , migration of smooth muscle cell from the media to the intima. Scales bars, 2 µ m (A) and 3 µ m (B, C, D).
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Figure 4: Transmission electron microscopy. Representative aspects of the prestenotic (A), poststenotic (B), sham-operated+HD and prestenotic+HD (C) and poststenotic+HD (D) segments. Panel A. The intima is thickened. The endothelial cells are heterogeneous, most of them with convoluted nuclei and cytoplasmic contours. Focal accumulation of smooth muscle cells could be seen in the expanded intimal layer. Migration of smooth muscle cells from the media into the intima (* ) through the fenestras of the internal elastic lamina can be also seen. Panel B. Marked intimal thickening composed of great number of smooth muscle cells surrounded by basement membrane-like material and collagen and elastic fibers can be seen. Migration of smooth muscle cells from the media into the intima (* ) is shown. Panel C. Represen-tative view of the small flat lesions corresponding to fatty streaks characterized by a few vacuolated mononuclear and smooth muscle cells accumulation. Panel D. Representative view of the poststenotic raised incipient atherosclerotic lesions composed of mononuclear and smooth muscle cells, many of them vacuolated, surrounded by extracellular matrix. End, endothelial cell; iel, internal elastic lamina; smc, smooth muscle cell; mc, mononuclear cell; * , migration of smooth muscle cell from the media to the intima. Scales bars, 2 µ m (A) and 3 µ m (B, C, D).

Mentions: In the hypertensive prestenotic segment from operated group, the intima appeared diffusely expanded mainly due to enlarged endothelial cells showing irregular nuclear and cytoplasmic contours resting on a basement membrane-like material and delicate fibrocollagenous support tissue. Focally distributed discrete neointimal plaques could be also detected. They were composed of clusters of smooth muscle cells, randomly arranged, surrounded by basement membrane-like material, collagen and young elastic fibers (Fig. 4A). Migration of smooth muscle cells from the media into the intima through the fenestras could also be seen. The media remained intact, the smooth muscle cells appearing unaltered, retaining their orientation to the vessel. In the poststenotic segment the intima appeared comparable to that of corresponding segment of sham-operated, except for focally distributed neointimal plaques, larger than those observed in the prestenotic segments. The foci were similar to those observed in the prestenotic segment, but of larger size. No changes could be observed in the media (Fig. 4B).


Aorta remodeling responses to distinct atherogenic stimuli: hypertension, hypercholesterolemia and turbulent flow/low wall shear stress.

Prado CM, Rossi MA - Open Cardiovasc Med J (2008)

Transmission electron microscopy. Representative aspects of the prestenotic (A), poststenotic (B), sham-operated+HD and prestenotic+HD (C) and poststenotic+HD (D) segments. Panel A. The intima is thickened. The endothelial cells are heterogeneous, most of them with convoluted nuclei and cytoplasmic contours. Focal accumulation of smooth muscle cells could be seen in the expanded intimal layer. Migration of smooth muscle cells from the media into the intima (* ) through the fenestras of the internal elastic lamina can be also seen. Panel B. Marked intimal thickening composed of great number of smooth muscle cells surrounded by basement membrane-like material and collagen and elastic fibers can be seen. Migration of smooth muscle cells from the media into the intima (* ) is shown. Panel C. Represen-tative view of the small flat lesions corresponding to fatty streaks characterized by a few vacuolated mononuclear and smooth muscle cells accumulation. Panel D. Representative view of the poststenotic raised incipient atherosclerotic lesions composed of mononuclear and smooth muscle cells, many of them vacuolated, surrounded by extracellular matrix. End, endothelial cell; iel, internal elastic lamina; smc, smooth muscle cell; mc, mononuclear cell; * , migration of smooth muscle cell from the media to the intima. Scales bars, 2 µ m (A) and 3 µ m (B, C, D).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
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Figure 4: Transmission electron microscopy. Representative aspects of the prestenotic (A), poststenotic (B), sham-operated+HD and prestenotic+HD (C) and poststenotic+HD (D) segments. Panel A. The intima is thickened. The endothelial cells are heterogeneous, most of them with convoluted nuclei and cytoplasmic contours. Focal accumulation of smooth muscle cells could be seen in the expanded intimal layer. Migration of smooth muscle cells from the media into the intima (* ) through the fenestras of the internal elastic lamina can be also seen. Panel B. Marked intimal thickening composed of great number of smooth muscle cells surrounded by basement membrane-like material and collagen and elastic fibers can be seen. Migration of smooth muscle cells from the media into the intima (* ) is shown. Panel C. Represen-tative view of the small flat lesions corresponding to fatty streaks characterized by a few vacuolated mononuclear and smooth muscle cells accumulation. Panel D. Representative view of the poststenotic raised incipient atherosclerotic lesions composed of mononuclear and smooth muscle cells, many of them vacuolated, surrounded by extracellular matrix. End, endothelial cell; iel, internal elastic lamina; smc, smooth muscle cell; mc, mononuclear cell; * , migration of smooth muscle cell from the media to the intima. Scales bars, 2 µ m (A) and 3 µ m (B, C, D).
Mentions: In the hypertensive prestenotic segment from operated group, the intima appeared diffusely expanded mainly due to enlarged endothelial cells showing irregular nuclear and cytoplasmic contours resting on a basement membrane-like material and delicate fibrocollagenous support tissue. Focally distributed discrete neointimal plaques could be also detected. They were composed of clusters of smooth muscle cells, randomly arranged, surrounded by basement membrane-like material, collagen and young elastic fibers (Fig. 4A). Migration of smooth muscle cells from the media into the intima through the fenestras could also be seen. The media remained intact, the smooth muscle cells appearing unaltered, retaining their orientation to the vessel. In the poststenotic segment the intima appeared comparable to that of corresponding segment of sham-operated, except for focally distributed neointimal plaques, larger than those observed in the prestenotic segments. The foci were similar to those observed in the prestenotic segment, but of larger size. No changes could be observed in the media (Fig. 4B).

Bottom Line: This review is based on recently published data from our laboratory.We investigated the role of hypertension and laminar flow, hypercholesterolemia and laminar flow and turbulent blood flow/low wall shear stress, and turbulent blood flow/low wall shear stress associated with hypercholesterolemia on aorta remodeling of rats feeding normal diet or hypercholesterolemic diet.Our findings suggest that increased circumferential wall tension due to hypertension plays a key role in the remodeling through biomechanical effects on oxidative stress and increased TGF-beta expression; the remodeling observed in the presence of hypercholesterolemia could be initiated by oxidative stress that is involved in several processes of atherogenesis and this remodeling is more pronounced in the presence of turbulent blood flow/low wall shear stress.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, S.P., Brazil.

ABSTRACT
This review is based on recently published data from our laboratory. We investigated the role of hypertension and laminar flow, hypercholesterolemia and laminar flow and turbulent blood flow/low wall shear stress, and turbulent blood flow/low wall shear stress associated with hypercholesterolemia on aorta remodeling of rats feeding normal diet or hypercholesterolemic diet. Our findings suggest that increased circumferential wall tension due to hypertension plays a key role in the remodeling through biomechanical effects on oxidative stress and increased TGF-beta expression; the remodeling observed in the presence of hypercholesterolemia could be initiated by oxidative stress that is involved in several processes of atherogenesis and this remodeling is more pronounced in the presence of turbulent blood flow/low wall shear stress.

No MeSH data available.


Related in: MedlinePlus