By Eleni Apostolatos ’18
In an argument with Dr. Frankenstein, the monster in Mary P. Shelley’s 1818 novella exclaims, “Man… how ignorant art thou in thy pride of wisdom!” The scathing irony of the monster’s statement is that he himself condoles the wisdom that designs him. Indeed, through scientific experiment, Frankenstein brings to life the infamous vile design, stitching it together from remnants of human corpses.
Tissue repair has long been sought-after in human history. The desire to recreate life has persisted for several centuries, as testified by popular stories like the Greek myth of Prometheus and the eternal renewal of his liver. While tissue engineering was originally manifested only in fantasy and myths, it has become an increasingly accessible and wholly feasible technology in the modern age.
Tissues are biological structures composed of identical cells that share the same phenotypes and express the same set of genes. The result of the aggregation of morphologically similar cells is a tissue that serves a specific function in the body. Two or more tissues comprise an organ.
Tissue engineering aims to find substitutes to restore, maintain or improve function of human tissues. The engineered tissue can become a permanent part of a patient’s body and a cure to a localized disease. Different techniques have been developed over the past century, but in its rawest form, tissue engineering concerns a scaffold system impregnated with cells that, together, perform the function of the tissue.
Research in Bone Regeneration
At Houston Methodist, a research team investigated solutions for faster bone regeneration in broken bones (1). Particularly, they studied fractures in long bones, which are dense and important for strength and mobility. Long bone injuries are generally complicated to treat, as they tend to involve a number of surgeries that introduce extraneous material into the body, such as rods, screws and external fixators. The team of researchers discovered a way to regenerate the large missing portions of long bones in a single surgery, without the use of hardware (1).
In 2014, the team designed two biomaterials that together compose a biomimetric scaffold that links ends of broken bone. They structured “materials to mimic natural, healthy tissues so the scaffolds are not rejected by the body’s immune system and guide the injured tissues to heal better and faster,” as claimed by Ennio Tasciotti, Ph.D., director of the Center for Biomimetic Medicine at Houston Methodist Tasciotti and the principal investigator, in a recent interview (1).
The scaffold’s two parts complement each other to accelerate the healing process for bone regeneration: a synthetic, load-bearing shell composed of a man-made, biodegradable polymer provides the mechanical stability, and a shell made up of natural biomineralized collagen promotes the bone cells’ growth. In their studies, the Houston Methodist team showed that neither growth factors nor mesenchymal stem cells are needed for tissue regeneration (1). In effect, after six weeks, the scaffold they construct enables bone growth, repairing the fracture and permitting full weightbearing activities, such as walking. The lab aims to attempt first-in-human clinical trials in the next years.
One of the benefits of the study is that orthopedic surgeons could potentially better treat patients in severe trauma cases, and avoid retreating to surgeries that result in significant disability or amputation. The novel approach of biomimetic tissue engineering is promising not only as a means to correct fractures but also to advance regenerative medicine technologies for applications in other disabilities.
Tissue Engineering in Organoid Formation
Organs, made up of several tissues, are being crafted through similar tissue engineering techniques. Scientists at Ohio State University grew an almost complete genetic equivalent to an embryonic human brain—a lab-grown organoid made up of tissue composed of skin cells. The organoids act as accurate brain models for researchers who want to test treatments to prevent or cure dramatic disorders, including Parkinson’s disease, autism, schizophrenia, epilepsy, Alzheimer’s, traumatic brain injuries and post-traumatic stress disorder (2).
The ultimate goal of this form of research is “taking skin cells, reverting them back to a basic stage of development and then teaching them how to turn into the cells that make up the brain,” as Dr. Sanjay Gupta, a scientist in the field, told CNN (2). It “is something we have been dreaming about for some time” (2)—and this development brings us closer to achieving this. Moreover, the ability to construct lab-grown brains may offer specificity in treatment: the best treatment for a patient can be found, as opposed to relying on the ‘one size fits all’ cure (2).
Furthermore, scientists all over the globe have been exploring brain tissue organoids for some time now. In 2008, Japanese scientists reconstructed a part of the brain, the cerebral cortex, using mice and human cells to form layered balls of tissue. Already in 2011, Madelain Lancaster from the Institute of Molecular Biotechnology in Vienna grew an embryonic brain. The recent embryonic brain model at Ohio State includes almost all parts of the brain, including the mid-brain, which is crucial to understanding diseases like Parkinson’s.
Where Tissue Engineering is Headed
Where will tissue engineering ultimately lead us? In addition to lab-grown models, cloning techniques are already being employed, where the cells of an individual are transplanted into another via tissue cloning mechanisms (5). The fields of tissue engineering and organoid formation are widespread—and they continue to grow, with medical applications reaching different fields in diverse ways. The results appear to be mostly beneficial in the medical platform. Let’s hope that tissue engineering is, indeed, wisdom we can be proud of—unlike the monster’s critique of Frankenstein’s then sordid creation.
(1) “Houston Methodist-led Research Team One Step Closer to Developing Technologies to Fix Broken Bones.” News-Medical.net. AZoM.com, 07 Oct. 2015. Web. 06 Oct. 2015.
(2) Patterson, Thom. “Scientist: We’ve Grown a Nearly Full Human ‘mini Brain’ – CNN.com.” CNN. Cable News Network, 22 Oct. 2015. Web. 25 Oct. 2015.
(3) Willyard, Casandra. “The Boom in Mini Stomachs, Brains, Breasts, Kidneys and More.” Nature.com. Nature Publishing Group, 29 July 2015. Web. 23 Oct. 2015.
(4) Miodownik, Mark. “How Laboratory-grown Organs Will Transform Our Lives.” The Guardian. Guardian News and Media Limited, 8 July 2015. Web. 24 Oct. 2015.
(5) A, Atala. “Result Filters.” National Center for Biotechnology Information. U.S. National Library of Medicine, July 2005. Web. 23 Oct. 2015.