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Iguana · 01-29-2008, 05:40 PM

Another one:

Mechanical Stretching Stimulates Smooth Muscle Cell Growth, Nuclear Protein Import, and Nuclear Pore Expression through Mitogen-activated Protein Kinase Activation*

Vascular smooth muscle cells that were mechanically stretched exhibited an increase in proliferating cell nuclear antigen expression, cell number, and cell size within 24–48 h.

Vascular smooth muscle cells (VSMCs)3 within the vessel wall are continuously exposed to mechanical cyclic strain due to changes in blood flow and pressure. Under normal conditions, the vessel wall is subjected to hemodynamic forces that can stretch the large arteries up to 10% (1–3). During conditions of hypertension, physical stress on the arterial vessel walls can increase to 30% (2, 4–6). This stretch directly leads to the growth of VSMCs (2, 7–10). Cell growth in the form of hyperplasia and/or cell hypertrophy is an active process that requires cells to enter the cell cycle through the induction of cell cycle regulatory proteins (11–14).

Mechanical Stretch of VSMCs Stimulates Cell Growth—VSMCs were mechanically stretched to stimulate cell growth. After 48 h of stretch, the cells exhibited a significant 5-fold increase in proliferating cell nuclear antigen expression when compared with non-stretched control cells (Fig. 1A). This would suggest that the stretched cells were actively entering the cell cycle. Cell counts confirmed that the cells were completing the cell cycle. There was a significant increase in cell number in a time-dependent manner as a function of the stretch stimulus (Fig. 1B)

Cell hypertrophy is another type of cell growth that may be stimulated by cell stretching. Cell hypertrophy was determined using the cytoplasmic probe calcein AM to measure total cell volume. Cells stimulated by stretching exhibited a significant increase in cell size compared with the non-stretched control group (Fig. 1C). This too was blocked in the presence of 1 µM PD98059. These results demonstrate that mechanical stretching is capable of inducing both hyperplasia and hypertrophy in the SMCs and that this appears to occur in an MAPK-dependent manner.

Mechanical Stretching Stimulates Smooth Muscle Cell Growth, Nuclear Protein Import, and Nuclear Pore Expression through Mitogen-activated Protein Kinase Activation -- Richard et al. 282 (32): 23081 -- Journal of Biological Chemistry

01-29-2008, 05:40 PM	#125 (permalink)
Iguana Co-Administrator Join Date: Oct 2007 Location: Lizardia Posts: 736 Rep Power: 10	Another one: Mechanical Stretching Stimulates Smooth Muscle Cell Growth, Nuclear Protein Import, and Nuclear Pore Expression through Mitogen-activated Protein Kinase Activation* Vascular smooth muscle cells that were mechanically stretched exhibited an increase in proliferating cell nuclear antigen expression, cell number, and cell size within 24–48 h. Vascular smooth muscle cells (VSMCs)3 within the vessel wall are continuously exposed to mechanical cyclic strain due to changes in blood flow and pressure. Under normal conditions, the vessel wall is subjected to hemodynamic forces that can stretch the large arteries up to 10% (1–3). During conditions of hypertension, physical stress on the arterial vessel walls can increase to 30% (2, 4–6). This stretch directly leads to the growth of VSMCs (2, 7–10). Cell growth in the form of hyperplasia and/or cell hypertrophy is an active process that requires cells to enter the cell cycle through the induction of cell cycle regulatory proteins (11–14). Mechanical Stretch of VSMCs Stimulates Cell Growth—VSMCs were mechanically stretched to stimulate cell growth. After 48 h of stretch, the cells exhibited a significant 5-fold increase in proliferating cell nuclear antigen expression when compared with non-stretched control cells (Fig. 1A). This would suggest that the stretched cells were actively entering the cell cycle. Cell counts confirmed that the cells were completing the cell cycle. There was a significant increase in cell number in a time-dependent manner as a function of the stretch stimulus (Fig. 1B) Cell hypertrophy is another type of cell growth that may be stimulated by cell stretching. Cell hypertrophy was determined using the cytoplasmic probe calcein AM to measure total cell volume. Cells stimulated by stretching exhibited a significant increase in cell size compared with the non-stretched control group (Fig. 1C). This too was blocked in the presence of 1 µM PD98059. These results demonstrate that mechanical stretching is capable of inducing both hyperplasia and hypertrophy in the SMCs and that this appears to occur in an MAPK-dependent manner. Mechanical Stretching Stimulates Smooth Muscle Cell Growth, Nuclear Protein Import, and Nuclear Pore Expression through Mitogen-activated Protein Kinase Activation -- Richard et al. 282 (32): 23081 -- Journal of Biological Chemistry __________________ May 2006: 5.75" X 4.5" - Now: 7.25" X 4.875" Let me tell you the secret that has led me to my goal: my strength lies solely in my tenacity. Louis Pasteur Last edited by Iguana : 01-29-2008 at 05:46 PM.