Intra-patient variability in sarcomeric protein phosphorylation within small left ventricular tissue samples was comparable between donor, HCM, and DCM samples, indicating biopsy-sized samples are representative of their region.
Observational (n=15)
Is there a difference in local sarcomeric protein phosphorylation variability in the free left ventricular wall between primary HCM, DCM, and non-failing donor hearts?
Small, biopsy-sized cardiac tissue samples are representative of the region of the free left ventricular wall from which they are obtained regarding protein phosphorylation, with comparable variability across HCM, DCM, and donor hearts.
p-value: p=>0.05
Cardiomyocyte contraction is regulated by phosphorylation of sarcomeric proteins. Throughout the heart regional and transmural differences may exist in protein phosphorylation. In addition, phosphorylation of sarcomeric proteins is altered in cardiac disease. Heterogeneity in protein phosphorylation may be larger in hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) as it may be caused by multiple mutations in genes encoding different sarcomeric proteins. Moreover, HCM is characterized by asymmetric remodelling of the heart. In the present study we assessed if local differences in sarcomeric protein phosphorylation are more evident in primary HCM or DCM than in non-failing donors. Thereto, phosphorylation of the two main target proteins of the beta-adrenergic receptor pathway, troponin I (cTnI) and myosin binding protein C (cMyBP-C) was analysed in different parts in the free left ventricular wall of end-stage failing HCM and DCM patients and donors obtained during transplant surgery. Intra-patient variability in protein phosphorylation within tissue samples of approximately 2 g wet weight was comparable between donor, HCM and DCM samples and could partly be attributed to the precision of the technique. Thus, our data indicate that within the precision of the measurements small, biopsy-sized cardiac tissue samples are representative for the region of the free left ventricular wall from which they were obtained.
Dijk et al. (Tue,) conducted a observational in End-stage primary cardiomyopathy (Hypertrophic and Dilated) (n=15). End-stage primary cardiomyopathy (HCM and DCM) vs. Non-failing donor hearts was evaluated on Intra-patient variability (coefficient of variation) in cMyBP-C and cTnI phosphorylation (p=>0.05). Intra-patient variability in sarcomeric protein phosphorylation within small left ventricular tissue samples was comparable between donor, HCM, and DCM samples, indicating biopsy-sized samples are representative of their region.