I am pleased to announce that my article "From Genetic Engineering to Genome Engineering: What Impact Has it Made on Science and Society?" was published in the Advanced Biology, Biotechnology and Genetics Journal. To read an electronic version, click here.

 Top

The definition of regenerative medicine, according to the National Institute of Health, is the process of creating living, functional tissues to repair or replace tissue or organ function lost due to age, disease, damage, or congenital defects.  It's a multidisciplinary approach comprised of biology, medicine, and engineering and includes tissue and stem cell engineering.

1. Type 1 Diabetes - Insulin-producing pancreatic islets could be regenerated in the body or grown in the laboratory and implanted, creating the potential for a cure for diabetes.
2. Stem Cell Therapy - Tissue-engineered heart muscle may be available to repair human hearts damaged by an event or disease.
3. 3D Printing - Organ Printing utilizes a standard ink jet printer modified with tissue matrix material (and possibly also cells) replacing the ink. "Made-to-order" organs of almost any configuration could then be cast and implanted.
4. "Smart" biomaterials - Materials Science meets Regenerative Medicine are being made that actively participate in, and orchestrate, the formation of functional tissue.
5. New approaches - Imagine revitalizing worn-out body parts, perhaps by removing the cells from an organ, and infusing new cells that would integrate into the existing matrix and restore full functionality.
6. No organ donor shortage - Imagine a world where there is no donor organ shortage, where damaged or failing organs and other human tissue can be replaced. A long-term promise of regenerative medicine, but a rapidly developing field of innovative therapies with the potential to offer a faster, more complete recovery with significantly fewer side effects or risk of complications.

3D printing has exploded onto the scene in the last couple of years, as the technology for 3D printing has become progressively less expensive and the idea that every household should own a 3D printer to create anything from household appliances to evening attire has become more widespread. This technology has rapidly expanded into the medical field, where currently physicians are using 3D printing to generate human organs destined for planning surgical procedures, or custom scoliosis braces, trachea tubes and even prosthetics, including eyes (Figure 1).

Figure 1: 3D printing has enabled scientists, using stem cells and/or various forms of scaffolding, to reproduce eyes and other human parts. Image: Liz Gill, Manchester Metropolitan University, UK

Scientists have also used stem cells and 3D printing to make miniature blood vessels (Figure 2) in Germany, human kidneys (Figure 3) in China, and livers in the US.   Although these organs have only survived for a few hours or a few days, the fact that scientists have been successful in printing live organs is nothing short of a miracle. The ultimate goal is organ transplant; eliminating the donor organ shortage is the prediction of tomorrow. If a patient needed a new organ, physicians and scientists would use the patient's own stem cells to print a new organ, transplant it into the patient and not be concerned with organ rejection. There would no longer be a "wait list" for organs, nor a black market for the trading of human organs, since they would be readily available at all times.

Figure 2:  3D printed blood vessels must work just like a normal vessel in directing nutrients to their destination.   Image: Fraunhofer Institute,Germany

Figure 3:  A printed 3D kidney that can function like a human kidney in terms of breaking down toxins and metabolites and can live for up to four hours.   Image: Professor Xu, Hangzhou Normal University, China

However, while we are waiting for scientists to perfect the printing of human organs, companies such as Organovo, which produced the first miniature human liver, are currently utilizing these livers and other human tissues for drug testing, and research and drug discovery applications by pharmaceuticals companies and academic research organizations.

4. "Smart" Biomaterials

Today's definition of a "smart" biomaterial is "biomaterials that allow for the gradual endogenous remodeling of native tissue leading to the replacement of implant material, manufactured to replace a missing biological structure, with fully functional [extracellular matrix] ECM and cells that existed at the implant site prior to damage."  In a nutshell, the biomaterial interacts and promotes tissue regeneration, with the native tissues and then slowly gets absorbed by the body as it is being replaced by native tissue. Another definition is, to use genes within the body to control the regeneration process. and using novel biomaterials that are gene-activated, where the tissue repair process can be specific for an individual and the disease.    Researchers must design implant materials that mimic the natural ECM that not only supports cellular structure, but also functions just as well, regulating growth, cell migration, differentiation, etc.

This type of tissue engineering has many challenges. Since the biomaterial must interact with and influence cell behavior and performance, scientists are trying to develop bioactive materials by incorporating signaling molecules, (i.e. neurotransmitters, cytokines and growth factors) into the scaffolding. 

Other challenges of tissue engineering, although not exclusive to the development of "smart" biomaterials, are to 1) stimulate the body to maintain its natural ability for new blood vessel formation; 2) provide an environment within the engineered biomaterial to support cellular proliferation and survival, a hallmark of functional tissue; 3) regenerate neurons and; 4) bone formation in vitro. Needless to say, this is a very complex task and discussion of possible solutions are beyond the scope of this article.

Humacyte, a North Carolina-based company, is making progress with blood vessels. The company is taking human cells and growing them as a scaffold in the shape of a tube.  When the scaffold or ECM is formed, the human cells are washed away to reduce the risk of rejection. Then the scaffold is implanted, allowing the patient's own tissue to grow into the vein. The technology is from Duke University and they will begin Phase III clinical trials.

5. New Approaches

Revitalizing worn out body parts will likely come to fruition once the tissue engineering challenges are solved. Solutions may not unfold in quite the way it was described "yesterday", but when we are able to help the body to regenerate damaged tissue through the help of bioactive materials, the outcomes would be the same. Likewise, 3D printing of organs, although not technically self - regeneration, can certainly be considered revitalization.

6. No organ donor shortage

3D printing of miniature human organs is a fantastic start. We will eventually get there, it's just a matter of time.