Energy-efficiency of Cardiomyocyte Stimulation with Rectangular Pulses

Posted on September 16, 2019 by Laasmaa M, Lu P, Veletić M, Louch WE, Bergsland J, Balasingham I, Vendelin M

Laasmaa M, Lu P, Veletić M, Louch WE, Bergsland J, Balasingham I, Vendelin M Sci Rep 2019 Sep;9(1):13307 PMID: 31527628 Abstract In cardiac pacemaker design, energy expenditure is an important issue. This work aims to explore whether varying stimulation pulse configuration is a viable optimization strategy for reducing energy consumption by the pacemaker. A single cardiomyocyte was used as an experimental model. Each cardiomyocyte was stimulated with different stimulation protocols using rec...

Respiration of permeabilized cardiomyocytes from mice: no sex differences, but substrate-dependent changes in the apparent ADP-affinity

Posted on August 29, 2019June 10, 2020 by Karro N, Laasmaa M, Vendelin M, Birkedal R

Karro N, Laasmaa M, Vendelin M, Birkedal R Sci Rep 2019 Aug;9(1):12592 PMID: 31467353 Abstract Sex differences in cardiac physiology are getting increased attention. This study assessed whether isolated, permeabilized cardiomyocytes from male and female C57BL/6 mice differ in terms of their respiration with multiple substrates and overall intracellular diffusion restriction estimated by the apparent ADP-affinity of respiration. Using respirometry, we recorded 1) the activities of respiratory...

IOCBIO Sparks detection and analysis software

Posted on April 10, 2019April 10, 2019 by admin

Laasmaa M, Karro N, Birkedal R, Vendelin M. PeerJ. 2019 Mar 29;7:e6652 PMID: 30956900 Full text: https://doi.org/10.7717/peerj.6652 Abstract Analysis of calcium sparks in cardiomyocytes can provide valuable information about functional changes of calcium handling in health and disease. As a part of the calcium sparks analysis, sparks detection and characterization is necessary. Here, we describe a new open-source platform for automatic calcium sparks detection from line ...

Seminar on heart physiology

Posted on December 8, 2016December 8, 2016 by admin

On 14th of December, at 14:00, there will be a seminar given by Pasi Tavi and William E. Louch. The talks are Prof. Pasi Tavi: Cardiac effects of PGC-1alpha. Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland Prof. William Edward Louch: Dyadic structure and function in cardiomyocytes: implications for heart failure. Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, ...

Thesis defense: Martin Laasmaa

Posted on December 6, 2016December 6, 2016 by admin

Martin Laasmaa is defending his thesis on Revealing Aspects of Cardiac Function from Fluorescence and Electrophysiological Recordings. Defense is on 14 December 2016 at 10:00 in the Institute of Cybernetics, room B101.

Revealing calcium fluxes by analyzing inhibition dynamics in action potential clamp

Posted on October 31, 2016 by Martin Laasmaa

Laasmaa M, Birkedal R, Vendelin M J. Mol. Cell. Cardiol. Volume 100, November 2016, Pages 93–108 PMID: 27702573 Full text: http://doi.org/10.1016/j.yjmcc.2016.08.015 Abstract In cardiac excitation-contraction coupling (ECC), calcium enters the cytosol via L-type Ca2+ channels (LTCC) and reverse Na+/Ca2+-exchange (NCXrev), or is released from the sarcoplasmic reticulum (SR) by Ca2+-induced Ca2+-release (CICR). The magnitude of Ca2+ influx via the different pathways varies with the ...

Metabolic compartmentation in rainbow trout cardiomyocytes: coupling of hexokinase but not creatine kinase to mitochondrial respiration

Posted on August 13, 2016October 30, 2016 by Karro N, Sepp M, Jugai S, Laasmaa M, Vendelin M, Birkedal R

Karro N, Sepp M, Jugai S, Laasmaa M, Vendelin M, Birkedal R J. Comp. Physiol. B, Biochem. Syst. Environ. Physiol. 2016 Aug; PMID: 27522222 Full text: http://doi.org/10.1007/s00360-016-1025-x Abstract Rainbow trout (Oncorhynchus mykiss) cardiomyocytes have a simple morphology with fewer membrane structures such as sarcoplasmic reticulum and t-tubules penetrating the cytosol. Despite this, intracellular ADP diffusion is restricted. Intriguingly, although diffusion is restricted, trout cardiom...

Restricted ADP movement in cardiomyocytes: Cytosolic diffusion obstacles are complemented with a small number of open mitochondrial voltage-dependent anion channels

Posted on May 31, 2016June 8, 2016 by Simson P, Jepihhina N, Laasmaa M, Peterson P, Birkedal R, Vendelin M

Simson P, Jepihhina N, Laasmaa M, Peterson P, Birkedal R, Vendelin M J. Mol. Cell. Cardiol. Volume 97, August 2016, Pages 197–203; PMID: 27261153 Full text: http://doi.org/10.1016/j.yjmcc.2016.04.012 Abstract Adequate intracellular energy transfer is crucial for proper cardiac function. In energy starved failing hearts, partial restoration of energy transfer can rescue mechanical performance. There are two types of diffusion obstacles that interfere with energy transfer from mit...

Thesis defense: Mari Kalda

Posted on December 2, 2015December 2, 2015 by admin

Mari Kalda is defending her thesis on Mechanoenergetics of a Single Cardiomyocyte. Defense is on 10 December 2015 at 10:00 in the Institute of Cybernetics, room B101.

Cross-Bridge Group Ensembles Describing Cooperativity in Thermodynamically Consistent Way

Posted on September 13, 2015September 13, 2015 by Kalda M, Peterson P, Vendelin M

Kalda M, Peterson P, Vendelin M PLoS ONE 2015;10(9):e0137438 PMID: 26361396 Full text: http://doi.org/10.1371/journal.pone.0137438 Abstract The aim of this work is to incorporate cooperativity into Huxley-type cross-bridge model in thermodynamically consistent way. While the Huxley-type models assume that cross-bridges act independently from each other, we take into account that each cross-bridge is influenced by its neighbors and cooperativity is induced by tropomyosin movement. For that...