Parameters: 3D Printed Human Hearts?

Source: BusinessInsider

One of the leading causes of death in the world today is cardiovascular disease.  The origination of the disease has been popularly attributed to the rise in obesity rates.  Yes, that is correct.  As Americans have gotten larger, obesity rates have soared and with them - a corresponding rise in cardiovascular disease has occurred.  Current treatments include being prescribed 'blood thinners' for the remainder of time.  What if there were another option?  Say, print a heart from existing blood cells. That is what was shown in the video below from 'USA Today':

Amazing. The technology offers to solve a huge issue.  Although, as noted in the video, there are several steps toward making the process happen.  Among the many challenges that lie between the laboratory and the human body, two dominant challenges stand out and which I would like to briefly address below.  Biocompatibility is probably going to be the most challenging of the steps.  Of course, the reprogramming of cells will be no easy challenge either.  Although, improvements through research have been made which I will briefly discuss below.

Biocompatibility

Biocompatibility is the ability of an artificial product (artificial -- heart, prosthetic piece, pace maker, etc.) to operate within the body (under physiological conditions) without being rejected.  I would be interested to see the process in further detail.  Nevertheless, the possibilities that 3D printing offers are emerging day by day and surely not restricted to the field of medicine.



To elaborate on the issue of 'biocompatibility' a bit more, I would like to add the introduction paragraph from Wikipedia shown below:

Biocompatibility is related to the behavior of biomaterials in various contexts. The term refers to the ability of a material to perform with an appropriate host response in a specific situation.[1] The ambiguity of the term reflects the ongoing development of insights into how biomaterials interact with the human body and eventually how those interactions determine the clinical success of a medical device (such as pacemaker, hip replacement or stent). Modern medical devices and prostheses are often made of more than one material so it might not always be sufficient to talk about the biocompatibility of a specific material.[2]

Since the immune response and repair functions in the body are so complicated it is not adequate to describe the biocompatibility of a single material in relation to a single cell type or tissue. Sometimes one hears of biocompatibility testing that is a large battery of in vitro test[3] that is used in accordance with ISO 10993 (or other similar standards) to determine if a certain material (or rather biomedical product) is biocompatible. These tests do not determine the biocompatibility of a material,[4] but they constitute an important step towards the animal testing and finally clinical trials that will determine the biocompatibility of the material in a given application, and thus medical devices such as implants or drug delivery devices[5].

Testing biocompatibility is a challenge too in certain cases.  The first and immediate test is the visual test - does the patient seem stable -- with stable vital signs?  From there, the specific tests inherent to the organ harvested (or printed) (ex: heart, liver, skin, etc.) are performed to check for biocompatibility.

Programming Cells?

The second greatest challenge I mentioned above was the process of reprogramming cells to become heart cells.  Over the last few decades much attention has been focused on understanding how a cell is programmed to become a cell in a specified organ (heart, liver, stomach, skin, etc.).  A major part of that research involved cell signaling research.  Ironically, the realizations (through research and discovery) that make this technology possible were researched by Professor Gunter Blobel of Rockefeller University - who recently passed away.  In a recent obituary in 'The New York Times' - Prof. Gunter Blobel's work was centered around proteins distribution around the body based on 'zip codes':

In 1971, Dr. Blobel and a colleague, Dr. David D. Sabatini, who later headed cell biology studies at the New York University School of Medicine, proposed a bold idea known as the “signal hypothesis.” It suggested that each protein carries in its structure a sequence of signals comparable to address tags on airport luggage or ZIP codes on mail to ensure that it all arrives safely.

The signals, Dr. Blobel found, are chains of amino acids created by protein-making machines that read distinctive RNA codes and then fix them on each new batch.

Like transmitters, these signals order receptors in membranes to open up watery holes so that proteins can pass through. They then act as GPS devices to cross the crowded terrain of a cell or a human body and, like finding a mailbox across the universe, penetrate precisely the right worksite organelle for each protein’s assigned task.

Proteins have many tasks: rebuilding or replacing constantly dying cells, protecting against viruses and bacteria, regulating body chemistry, reading DNA to make new molecules, releasing hormones to signal and repair tissues and organs, carrying and binding atoms throughout the body, and many other functions.

Despite proteins’ variety and complexity, however, Dr. Blobel demonstrated that their signaling system for getting through barriers and finding their worksites is universal, operating similarly in all animals, plants and even common yeasts.

Moreover, he found, this signaling system has evidently been working quite smoothly for millions of years, since the evolution of the first cell. Mistakes can be catastrophic to an organism, but they are relatively rare.

As you can see, Professor Gunter Blobel's work in cell signaling is critical toward inventions like the the 3D printed heart being heralded above as the next wave of technology coming out of 3D printing.

Conclusions....

Exciting as the possibility may be to fabricate a human heart, the advances in understanding cell programming/signaling is equally as exciting toward curing an array of diseases in the foreseeable future.  Research and discovery is the avenue by which these advances start in their long and arduous process of becoming realized as technologies down the line.  An example is the length and cost of drug discovery research.  I have written (an introductory post) on the process (and cost) of drug discovery.



Advances such as a 3D heart are exciting and should be aimed at achieving.  I will be interested to report further on additional advances in technologies such as 'biocompatibility' of which harvesting an artificial heart (that works) is just one example.  Medicine is advancing quickly.  But the gap in understanding just how to treat an array of diseases with technology is still enormous in most situations.  Which is also motivating to toward moving forward in our search for the answer.  Stay tuned.



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