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[Myocardial regulatory proteins in children with congenital heart defects]
1Univerzita Karlova v Praze, Lékarská fakulta v Hradci Králové: Ustav fyziologie, Univerzita Karlova v Praze. adamcova@lfhk.cuni.cz
Insights
This study analyzed cardiac troponin T (cTnT) protein fractions in children with congenital heart disease. Hypoxemia did not alter the distribution between cytosolic and myofibrillar cTnT pools.
Area of Science:
- Cardiology
- Biochemistry
- Molecular Biology
Context:
- Congenital heart diseases (CHDs) in children present diverse physiological challenges.
- Myocardial tissue samples were analyzed from pediatric patients undergoing surgery for CHDs.
- Patients were categorized into normoxaemic (e.g., septal defects) and hypoxaemic (e.g., tetralogy of Fallot) groups.
Purpose:
- To compare the protein profiling of regulatory proteins, specifically cardiac troponin T (cTnT).
- To investigate the distribution of cTnT between cytosolic and myofibrillar fractions in pediatric myocardial tissue.
- To determine the effect of hypoxaemia on cTnT compartmentalization in children with CHDs.
Summary:
- Cardiac troponin T (cTnT) was isolated from cytosolic and myofibrillar fractions of right ventricular and atrial muscle in pediatric patients.
- Protein concentrations were quantified, and cTnT fractions were analyzed using SDS-PAGE and immunoblotting.
- The cytosolic pool constituted approximately 12.5% and the myofibrillar pool 87.5% of total cTnT.
- This distribution remained consistent regardless of the patient's oxygen saturation levels (normoxaemic vs. hypoxaemic).
Impact:
- Provides insights into the protein composition of regulatory proteins in pediatric hearts with CHDs.
- Establishes baseline data for cTnT compartmentalization in pediatric myocardial tissue.
- Suggests that hypoxaemia, a common complication in certain CHDs, does not significantly alter cTnT distribution in the studied pediatric population.
Abstract:
The purpose of this study was to compare the protein profiling of the regulatory proteins. The samples of myocardial tissue were obtained during surgical intervention from children (age 8.2 +/- 1.8 years) operated for different types of congenital heart diseases. The arterial oxygen saturation was 95.5 +/- 0.07% in normoxaemic patients (ventricular and atrial septal defects), resp. 76.9 +/- 2.1% in hypoxaemic patients (tetralogy of Fallot). The both cytosolic and myofibrillar fractions of cardiac troponin T (cTnT) were isolated by stepwise extraction (4) from the both right ventricular and right atrial musculature. The concentration of proteins was measured using Coomasie Plus Protein Reagent Kit (Pierce). After isolation, one-dimensional SDS polyacrylamide gel electrophoresis was carried out according to a modified version of the method of Laemmli (1970), using a 12% separating gel and a 4% stacking gel. In some cases after SDS-PAGE, proteins were electroblotted onto nitrocellulose membrane for immunoblotting and analysed using the JLT-12 monoclonal antibodies (Sigma Chemicals). The cytosolic pool of cTnT (measured by commercial kit Elecsys Troponin T STAT Immunoassay--Roche) represents about 12.5%, the myofibrillar pool of cTnT was about 87.5%; hypoxaemia did not affect this proportion.