For patients with heart damage, the best treatment option right now is an organ transplant. But even then, the patient waiting list for an organ donor is seemingly endless. To confound matters, patients can encounter complications after heart transplantation.

With new research, the ideal solution — repairing the heart — may soon be possible.

The biggest challenge scientists faced was building the right material to function as the heart's scaffold. The complex structure of the human heart is designed to withstand a lifetime of pumping force without tiring and ripping its own fibers apart.

To mimic the heart's powerful mechanical action, scientists needed to engineer an artificial cardiac tissue similar in elasticity and biological properties to the native heart. And the breakthrough scientists have long been waiting for has arrived — 3-D-engineered heart tissue that beats.

This exciting breakthrough comes on the heels of a previous medical leap in August of 2013 involving induced pluripotent stem cells (IPSCs). In many ways similar to a skin biopsy procedure, IPSCs are stem cells manually created from the cardiac muscle and treated to become multipotential cardiovascular progenitor (MCP) cells.

These cells develop into three types found in the human heart — cardiomyocytes, smooth muscle cells and endothelial cells. When MCPs are introduced to the heart scaffold, they slowly develop into a beating heart.

MeTro Hydrogels from Wyss Institute on Vimeo.

The heart's ability to regenerate and repair itself is curiously limited. By the time cardiomyocytes are at the adult cycle, they have already lost most of their potential to proliferate. In transplant research, their use in the cell-culture model serves little purpose. Note that poor lifestyle habits can activate a series of apoptotic changes in the heart, making an individual more susceptible to heart disease later in life.

For years, basic research has been hampered by the lack of specimens that involve heart muscle cells. The absence of myocytes in experiments has massively affected major advancements in cardiology.

Experiments needed to green-light specific applications — safety in pharmacology, the development of cellular therapies and in vitro engineering — have stagnated in their wake.

Scientists, working on a way to repair the heart, engineered tissue that "closely mimics the natural heart muscle" and beats when implanted into animals. The breakthrough research was presented in a meeting of the American Chemical Society.

The first crucial step in this feat was building the right raw materials that could closely match the tough, yet pliable matrix of the heart muscle.

Researchers came up with the novel idea of using natural proteins called hydrogels that resembled gelatin and featured water-loving properties much like human tissue. But their ability to expand and contract against a heartbeat, in similar function to the complex human heart, was grossly lacking.

Next, scientists engineered a new family of elastic human protein, called tropoelastin. Like its name, it behaved remarkably similar to the elasticity of the heart — the missing ingredient in the earlier model — with the strength and resilience to match.

It came down to the final hurdle: growing actual heart cells on this bioengineered, programmable structure. With the help of 3-D printing and microengineering techniques, the last pieces of the puzzle came together. Heart tissue that pulsed with life then evolved.

More experiments are underway for this medical milestone that promises to improve our quality of life. Eventually, these elastic natural hydrogels will function as cardiac patches for heart patients.

The prognosis is bright for millions of patients who suffer from cardiovascular disease. Scientists are also looking to regenerate other tissues, such as blood vessels, skeletal muscles and heart valves, using elastic hydrogels.