cardiovascular system
• 13 month old adults exhibit increased levels of the following cytoskeleton components: intermediate filament protein, desmin, and alpha-B-crystallin, in hearts
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• individual myocytes exhibit oval-shaped foci
• myofibrils show signs of disorganization with T-tubules slightly distended and some mitochondria showing abnormal morphology
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• scattered degenerating myocytes, adjacent to normal cells, are seen throughout the chambers of the heart
• ventricular myocytes in late stages of dysgenesis show some profiles of sarcoplasmic reticulum, lipid droplets, and a rim of myofibrils along the sarcolemma in degenerated parts of the cell
• however, mice show no cardiac hypertrophy or dilation at 25 weeks of age and no differences in heart contraction, relaxation, or responses to increased workload, or morbidity or mortality
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• heart weight/body weight ratios are increased about 17% compared to controls
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• mild cardiac hypertrophy develops in older mice (about 14 months of age)
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• mice exhibit a slower heart rate during exercise sessions, with about 50% of mice showing a precipitous drop in heart rate
• mice subjected to beta-adrenergic stimulation via subcutaneous isoproterenol administration exhibit decreased heart rates after the third day of the trial
• however, no cardiac hypertrophy results from exercise
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• the 2 of 12 mice administered isoproterenol that die showed sinus bradycardia
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• isolated ventricular fibers show increased calcium sensitivity to force development and decreased maximum relative power
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• mice subjected to treadmill exercise exhibit a decrease in exercise capacity with slower heart rate and death during or after exercise trail in 50% of mice
• mice treated with isoproterenol to induce beta-adrenergic stimulation exhibit reduced heart rates and a low level of death
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behavior/neurological
• 4 of 8 mice subjected to sub-maximal treadmill exercise die during or immediately after the exercise trial
• mice show decrease in exercise capacity as evidenced by decreased exercise duration and increased bar touches
• mice older than 1 year of age fail to maintain even modest levels of performance on the treadmill
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muscle
• individual myocytes exhibit oval-shaped foci
• myofibrils show signs of disorganization with T-tubules slightly distended and some mitochondria showing abnormal morphology
|
• scattered degenerating myocytes, adjacent to normal cells, are seen throughout the chambers of the heart
• ventricular myocytes in late stages of dysgenesis show some profiles of sarcoplasmic reticulum, lipid droplets, and a rim of myofibrils along the sarcolemma in degenerated parts of the cell
• however, mice show no cardiac hypertrophy or dilation at 25 weeks of age and no differences in heart contraction, relaxation, or responses to increased workload, or morbidity or mortality
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• ventricular myocytes in the early degenerative stages show a lack of sarcomeric organization in only small areas adjacent to the nucleus
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homeostasis/metabolism
• 4 of 8 mice subjected to sub-maximal treadmill exercise die during or immediately after the exercise trial
• mice show decrease in exercise capacity as evidenced by decreased exercise duration and increased bar touches
• mice older than 1 year of age fail to maintain even modest levels of performance on the treadmill
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• mice subjected to treadmill exercise exhibit a decrease in exercise capacity with slower heart rate and death during or after exercise trail in 50% of mice
• mice treated with isoproterenol to induce beta-adrenergic stimulation exhibit reduced heart rates and a low level of death
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mortality/aging
• 4 of 8 mice subjected to sub-maximal treadmill exercise die during or immediately after the exercise trial
• 2 of 12 mice administered isoproterenol die in early stages, between the third and fourth days
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growth/size/body
• heart weight/body weight ratios are increased about 17% compared to controls
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• mild cardiac hypertrophy develops in older mice (about 14 months of age)
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Mouse Models of Human Disease |
DO ID | OMIM ID(s) | Ref(s) | |
hypertrophic cardiomyopathy 4 | DOID:0110310 |
OMIM:115197 |
J:50237 , J:127656 |