Kinetics of a single cross-bridge in familial hypertrophic cardiomyopathy heart muscle measured by reverse Kretschmann fluorescence

Prasad Mettikolla, Nils Calander, Rafal Luchowski, Ignacy Gryczynski, Zygmunt Gryczynski, Julian Borejdo

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Familial hypertrophic cardiomyopathy (FHC) is a serious heart disease that often leads to a sudden cardiac death of young athletes. It is believed that the alteration of the kinetics of interaction between actin and myosin causes FHC by making the heart to pump blood inefficiently. We set out to check this hypothesis ex vivo. During contraction of heart muscle, a myosin cross-bridge imparts periodic force impulses to actin. The impulses are analyzed by fluorescence correlation spectroscopy (FCS) of fluorescently labeled actin. To minimize observation volume and background fluorescence, we carry out FCS measurements in surface plasmon coupled emission mode in a reverse Kretschmann configuration. Fluorescence is a result of near-field coupling of fluorophores excited in the vicinity of the metal-coated surface of a coverslip with the surface plasmons propagating in the metal. Surface plasmons decouple on opposite sides of the metal film and emit in a directional manner as far-field p-polarized radiation. We show that the rate of changes of orientation is significantly faster in contracting cardiac myofibrils of transgenic mice than wild type. These results are consistent with the fact that mutated heart muscle myosin translates actin faster in in vitro motility assays.

Original languageEnglish
Article number017011
JournalJournal of Biomedical Optics
Volume15
Issue number1
DOIs
StatePublished - 2010

Keywords

  • Fluorescence spectroscopy
  • Microscopy
  • Surface plasmons

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