Electricity Forms Your Heart
Did you know your heart is an electrical appliance? That’s right. Currents of electrical ions are vital to its function as a contractile organ. Now, researchers at the University of California have found another thing electricity does for your heart: it guides the developing heart into the proper shape. This is a key study showing how epigenetic factors – factors above and beyond the genetic code – are essential for the formation of body parts.
The research team, publishing in PNAS,1 explained the purpose of their investigation (Note: morphogenesis refers to the origin of shape, and cardiomyocytes are the specialized muscle cells that make the heart beat):
Cardiac morphogenesis is a complex process that is mediated by a coordinated set of cellular and molecular as well as environmental factors. Recent studies have shown that epigenetic forces such as cardiomyocyte contractility and intracardiac hemodynamic flow regulate this process. Furthermore, in vitro studies suggest that cardiomyocytes can realign themselves according to electrical conduction directionality. However, because electrical cardiac conduction and mechanical contractile forces are intimately coupled in the intact heart, it is difficult to assess the individual contribution of these influences to overall heart organogenesis. Here, we make use of several zebrafish cardiac mutants to uncouple these two influences, and find that electrical conduction exclusive of contractile influences can directly participate in remodeling and morphogenesis of the vertebrate heart.
In other words, electrical conduction guides the individual heart cells into position during heart development and repair. They said in the Discussion part of their paper that it is known that “The direction of growth and orientation of various cell types in tissue culture can be influenced by externally applied electric fields.” They added, “Furthermore, endogenous [inside organism] electric currents exist in a variety of tissues and have been hypothesized to influence cell migration and shape.” This paper announces confirmation of that hypothesis for heart formation: “Our in vivo results [using living zebrafish] indicate that physiologic electric currents can indeed have an impact on cell morphology and overall cardiac organogenesis.” The mutant fish without the electrical conduction working properly developed heart disease.
So how does this work? They explained, “These electrical effects might be mediated through intracellular calcium fluxes which can affect cell polarization. Furthermore, a number of cell surface receptors… can also be redistributed in the cell membrane by electric fields.” Does this finding provide hope for heart patients? Patients with electrical conduction disorders get better when the beats are re-synchronized. The researchers explained why that works: “Thus, overall cardiac improvement from the resynchronization of the ventricles in heart failure patients manifesting conduction disorders may be due to beneficial realignment and improved remodeling of the myocardium primarily from proper and synchronized electrical signaling.” Get the electricity right, and the heart shapes up. Now those defibrillation devices and electrical heart stimulators start to make more sense.
This means that stem cell therapy (07/20/2010) may need an electrical jumpstart to work properly: “Given that previous cardiac cell-based therapy has provided only a modest improvement in cardiac function,” they ended, pointing therapy in a new direction, “electrical cell?cell communication and stimulation may be required for optimal integration and alignment of engrafted embryonic cardiomyocytes and skeletal myoblasts in the injured myocardium to improve overall myocardial performance.” Live better electrically!
1. Chi, Bussen et al, “Cardiac conduction is required to preserve cardiac chamber morphology,” Proceedings of the National Academy of Sciences, published online July 30, 2010, doi: 10.1073/pnas.0909432107.
This fascinating discovery is but the tip of an iceberg that will guide biology into the future: epigenetics. We have learned much about genetics – the DNA code that provides the information for building proteins and the cell’s building blocks. But genetics does no more than deliver the bricks, pipes and wire to the construction site and drop off a blueprint. What directs the parts into their correct position at the correct time? What makes some genes get expressed in cardiac cells, and other genes get expressed in nerve cells? If all the cells have the same blueprint, why do they become so different in different parts of the body? Clearly much more is going on than providing each cell with a blueprint.
Here we see one example of an epigenetic factor, where electrical currents are involved. Imagine how precise these currents must be positioned to guide cells into the shape of an auricle or ventricle, to say nothing of guiding all the ancillary nerve cells and blood vessels into place. What switches on the electrical currents, and orients them properly? Do you get a brief glimpse of mind-boggling complexity going on inside the womb as a baby’s heart forms and begins beating in just 9 or 10 weeks from the time the baby began as a single cell?
The complexity of development was presented briefly in the second half of the recent film Darwin’s Dilemma from Illustra Media. Scientists like Richard Sternberg and Jonathan Wells commented that the complexity of development and epigenetic factors is so vast, so poorly understood, so impermeable to an origin by chance, it leaves regular genetics far behind. Did the PNAS scientists need to ask Darwin for help? Ha! They needed him like a hole in the heart. They never mentioned evolution once in their paper. Odd, isn’t it, when the Darwiniacs assure us that nothing in biology makes sense except in the light of evolution.
Science is only beginning to ask the questions about how factors beyond genetics guide molecules into specialized cells, then tissues, then organs, then a complete organism (the computer graphics in Darwin’s Dilemma are excellent for illustrating this). Morphogenesis cannot be described in a one-dimensional code. There are hierarchies of codes involved in the development of each cell and organism. If Darwin could not survive a genetic code arising by chance (see online book), how on earth will he survive hierarchies of codes? In the condition his theory was already in, it’s enough to cause a massive coronary.
You have a designed heart; so have a heart for design, because the future looks healthy for intelligent design science.