A new study published in the American Journal of Pathology reveals that structural and morphological changes to the heart start to occur immediately in response to a cardiac injury.
"We analyzed and have demonstrated for the first time the early interaction and coordination of morphological changes, cell populations, and gene expression following pathological cardiac insult," reports lead investigator Troy A. Baudino, PhD, of the Cardiovascular Research Institute at Texas A&M Health Science Center, Temple, TX. "The time course of our study allows these events to be correlated to one another, providing valuable insight for future studies of cardiac pathology."
The investigators induced heart injury in mice through transverse aortic constriction (TAC). A control group of mice underwent a surgical procedure without the aortic constriction, for comparison. They evaluated acute cardiac modeling events beginning two days after surgery, including changes in hypertrophy, collagen deposition, capillary density, and cell populations.
Investigators observed increased fibroblasts and collagen seven days following TAC, contributing to the increased heart weight between two and seven days after injury. "We found that these changes take place concurrently with vascular re-growth," says Dr. Baudino. "It is possible that while the expanding fibroblast population is depositing excess extracellular material, a process that stiffens the heart, it also simultaneously stimulates capillary growth, to deliver more oxygen and nutrients to the expanding myocardium. Given this implication, regulation of fibroblasts may offer an advantageous route of therapy."
Dr. Baudino notes that the human response to pressure overload such as hypertension is more gradual than in the TAC mouse model and may vary with respect to the specific timing of remodeling. "Future studies should examine the remodeling events in a clinical setting. However, our results provide a basis for investigating how these events are coordinated during remodeling and the importance of possible intervention before pathological remodeling appears," he concludes.