There is circumstantial clinical evidence to suggest that patients with hypertrophic cardiomyopathy (HCM) have disordered regulation of intra-cellular calcium. The hypercontractile myocardium with poor diastolic relaxation could be explained, for example, by increased cytosolic Ca+2 in the cardiac myocyte. Given that some forms of HCM are genetically transmitted, we postulated that a disorder of cytosolic calcium metabolism might be present in other, non-cardiac tissue. To study this, we isolated platelets from the plasma of patients with HCM and normals and measured intra-cellular calcium levels using the fluorescent indicator QuinII. Our preliminary results (on only a small number of patients and controls) indicates that resting Ca+2 levels are the same in these populations. When the cells are stimulated with vasopressin -- which causes both intra- cellular calcium mobilization and Ca+2 influx -- some patients appear to have a blunted response to this stimulant. Whether this is an epiphenomenon still remains to be determined, but if these results are substantiated, they point to wide-spread Ca+2 dysregulation. The mechanism of this could be determined and might give us an important clue as to the etiology of this disease.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Intramural Research (Z01)
Project #
1Z01HL004113-03
Application #
3942933
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
3
Fiscal Year
1987
Total Cost
Indirect Cost
Name
U.S. National Heart Lung and Blood Inst
Department
Type
DUNS #
City
State
Country
United States
Zip Code