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Updated: May 13, 2026
Measurement of Antibody Effects on Cellular Function of Isolated Cardiomyocytes
Published on: March 8, 2013
Measurement of antibody effects on cellular function of isolated cardiomyocytes
Lars G Eckerle1, Stephan B Felix, Lars R Herda
1Department of Internal Medicine B, University Medicine Greifswald.
Insights
Researchers developed a new method to detect active cardiac autoantibodies in dilated cardiomyopathy (DCM) patients. This technique identifies functionally effective antibodies, regardless of their specific target antigen, aiding in understanding DCM
Area of Science:
- Cardiology
- Immunology
- Biochemistry
Background:
- Dilated cardiomyopathy (DCM) is a primary cause of heart failure in young adults, with unknown origins in many cases.
- Cardiac autoantibodies are implicated in DCM pathogenesis, and their removal improves patient hemodynamics.
- Current immunoassays cannot distinguish between functionally effective (stimulating) and non-effective (blocking) autoantibodies, nor detect antibodies with unidentified targets.
Purpose of the Study:
- To establish a novel method for detecting functionally active cardiotropic antibodies in DCM patients, independent of known antigens.
- To assess the functional impact of patient-derived IgG on cardiomyocyte contractility and calcium transients.
Main Methods:
- Isolated IgG from DCM patient plasma using immunoadsorption-derived antibodies.
- Isolated adult rat cardiomyocytes and cultured them on laminin-coated surfaces.
- Monitored cardiomyocyte shortening and calcium (Ca2+) transients in response to patient IgG using a specialized imaging system.
Main Results:
- The study successfully developed and applied a method to test the functional activity of cardiotropic antibodies.
- Patient-derived IgG was assessed for its effects on cardiomyocyte function, providing insights into antibody activity.
- The cross-reactivity of human cardiac antibodies with rat cardiomyocytes was leveraged for functional testing.
Conclusions:
- The developed method allows for the detection of functionally relevant cardiotropic autoantibodies in DCM.
- This approach offers a way to identify antibodies that actively influence cardiac function, irrespective of their specific antigen.
- This technique holds promise for a deeper understanding of autoimmune mechanisms in DCM and for identifying novel therapeutic targets.
Abstract:
Dilated cardiomyopathy (DCM) is one of the main causes for heart failure in younger adults. Although genetic disposition and exposition to toxic substances are known causes for this disease in about one third of the patients, the origin of DCM remains largely unclear. In a substantial number of these patients, autoantibodies against cardiac epitopes have been detected and are suspected to play a pivotal role in the onset and progression of the disease. The importance of cardiac autoantibodies is underlined by a hemodynamic improvement observed in DCM patients after elimination of autoantibodies by immunoadsorption. A variety of specific antigens have already been identified and antibodies against these targets may be detected by immunoassays. However, these assays cannot discriminate between stimulating (and therefore functionally effective) and blocking autoantibodies. There is increasing evidence that this distinction is crucial. It can also be assumed that the targets for a number of cardiotropic antibodies are still unidentified and therefore cannot be detected by immunoassays. Therefore, we established a method for the detection of functionally active cardiotropic antibodies, independent of their respective antigen. The background for the method is the high homology usually observed for functional regions of cardiac proteins in between mammals. This suggests that cardiac antibodies directed against human antigens will cross-react with non-human target cells, which allows testing of IgG from DCM patients on adult rat cardiomyocytes. Our method consists of 3 steps: first, IgG is isolated from patient plasma using sepharose coupled anti-IgG antibodies obtained from immunoadsorption columns (PlasmaSelect, Teterow, Germany). Second, adult cardiomyocytes are isolated by collagenase perfusion in a Langendorff perfusion apparatus using a protocol modified from previous works. The obtained cardiomyocytes are attached to laminin-coated chambered coverglasses and stained with Fura-2, a calcium-selective fluorescent dye which can be easily brought into the cell to observe intracellular calcium (Ca(2+)) contents. In the last step, the effect of patient IgG on the cell shortening and Ca(2+) transients of field stimulated cardiomyocytes is monitored online using a commercial myocyte calcium and contractility monitoring system (IonOptix, Milton, MA, USA) connected to a standard inverse fluorescent microscope.
