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Pregnancy induces cardiac hypertrophy with hypercontractile ventricular myocytes
Author(s) -
Kennard Kaitlyn,
Foster-Bey Lianna,
Yanessa Deborah,
Bailey Beth A
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1139.10
Subject(s) - myocyte , medicine , endocrinology , cardiac myocyte , muscle hypertrophy , sarcomere , cardiac function curve , volume overload , cardiology , collagenase , basal (medicine) , pregnancy , biology , heart failure , biochemistry , genetics , insulin , enzyme
Pregnancy induces an increase in the physiological stress of the heart. The stress is primarily volume overload that results in increased cardiac output required to support the fetus(s). Persistent volume overload induced by pathological conditions result in cardiac function defects. The objective of the current study was to determine if volume overload during pregnancy disrupts cardiac myocyte contractile properties. Hearts from full term pregnant mice were removed, weighed and the aortas cannulated to isolate single ventricular myocytes via collagenase digestion. Rod shaped ventricular myocytes were placed in a chamber mounted on the stage of an inverted microscope and perfused with a physiological salt solution. Myocytes were electrically paced at 4Hz and shortening was measured with an IonOptix system. Hearts from pregnant mice (PM) were hypertrophied versus age and sex matched controls (CM) (239±7.3 vs 206±3.5 mg). Cardiac myocytes isolated from PM had significant increases in length (133±3 vs 119±2μ) and surface area (3380±177 vs 2844±78μ 2 ) but no change in width. Contractions (% of resting sarcomere length) of myocytes from PM were increased (10.4±.7 vs 7.9±.7) versus CM as were the rates of shortening (3.92±.4 vs 3.08±.2 %RSL/sec) and relengthening (3.56±.3 vs 2.83±.25). Pregnancy induces physiological cardiac and myocyte hypertrophy accompanied by enhanced basal contractile performance.