| Project/Area Number |
17500325
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biomedical engineering/Biological material science
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| Research Institution | National Cardiovascular Center Research Institute |
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Principal Investigator |
SHISHIDO Toshiaki National Cardiovascular Center Research Institute, Dept of Cardiovascular Dynamics, Laboratory Chief, 循環動態機能部, 室長 (60300977)
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| Co-Investigator(Kenkyū-buntansha) |
SUGIMACHI Masaru National Cardiovascular Center Research Institute, Dept of Cardiovascular Dynamics, Director, 循環動態機能部, 部長 (40250261)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2005: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | ventricle / cardiomyocyte / heart disease / biomechanics / contractility / time-varying elastance model / 可変弾性モデル |
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| Research Abstract |
1.To test whether the minute vibration technique can separate viscosity and elasticity of the cardiac myocyte, we quantitatively assessed the regional myocardial elasticity and viscosity using this technique. Time-varying regional myocardial viscosity as well as elastance increased from diastole to systole and linearly correlated with time-varying ventricular elastance.
2.We applied this technique in the regional myocardium to an isolated cardiac myocyte. Nanoscale vibration was generated by atomic force microscope. However, there was only a small difference in the calculated viscoelasticity between the end-systolic and the diastolic phases. Moreover, there was no change of this difference between systole and diastole under the unstressed conditions after the contractility was enhanced by dobutamine.
3.We developed a new device to stretch an isolated cardiac myocyte and tried to measure the viscoelasticity of a cardiac myocyte under the loading conditions. However, the isolated cardiac m
… More
yocytes were easily peeled off from the culture sheet because it was difficult to stretch the sheet uniformly.
4.Maximizing yield of viable cardiac myocytes is most important in the processing of small human myocardial biopsies. We established the conditions of protease and collagenase digestion of ventricular myocardium to obtain viable cardiac myocytes in adults rats. The combination of 4U/ml protease (type XXIV) and 400U/ml collagenase-A was more effective than either enzyme alone in increasing viable cardiac myocytes.
5.We developed a computer model to relate cardiomyocyte-level viscoelasticity to whole-heart contractility. This model was based on Laplace's law and applied across a multilayer of myocardium. We could integrate the stress-strain relationship in cell-level to the pressure-volume relationship in heart-level.
In the next phase, we are planning to measure the viscoelasticity of an isolated cardiac myocyte by the cell fixation technique that uses a pair of carbon fibers to clamp a cardiac myocyte. Less
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