Thursday, October 11, 2018

Study reveals that Cardiomyopathy mutation reduces heart's ability to vary pumping force.


Recently, the Researchers have found how a genetic mutation is associated to hypertrophic cardiomyopathy (HCM) disrupts the heart's normal function. The study reveals that the mutation prevents the heart from increasing the amount of force it produces when it needs to pump additional blood around the body. 
Inherited genetic mutations can cause in the heart muscle which can abnormally thick and reduce the pumping of enough blood around the body. Studies have identified a mutation in the heart muscle protein troponin T that seem to pose a particularly high risk of sudden death in children and adults, despite it having only a mild thickening of the heart muscle wall. The mutation, known as F87L, alters a single amino acid in the central region of troponin.

Troponin complex component Troponin T which allows muscle fibers to contract in response to calcium released upon electrical stimulation. One of the significant features of cardiac muscle filaments is: they become more sensitive to calcium and hence contract more strongly, because they are stretched to longer lengths. Hence, when heart is filled with more blood, especially during carrying out physical activity, the muscle walls stretches and the heart contracts with high force to pump out extra blood. This phenomenon, which is known as the Frank-Starling mechanism is mainly due to Troponin action.

 A professor along with a graduate student carried out research and introduced an equivalent mutation in the cardiac troponin T gene of guinea pigs and analyzed how it can affects the guinea pigs cardiac muscle fibers ability to contract and produce force. They found that the mutation: F87L in troponin T destroys the length-dependent increase in calcium sensitivity. the same response to calcium was observed in short, unstretched muscle fibers expressing mutant troponin T showed just as longer, stretched fibers.

The data resulted demonstrate that the length-mediated increase in force is significantly decreased by this hypertrophic cardiomyopathy (HCM)-associated mutation, which suggested that the mutation may direct muscle length-mediated increase in force production in the heart.. The effect of the Frank-Starling mechanism may have severe consequences for any individual as it decreases the heart's ability to increase output when it needs to pump additional blood around the body.

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