Regenerative medicine

The term regenerative medicine refers to a number of techniques in which human cells, tissues or organs are
replaced or regenerated
in order to reverse birth defects or to repair damage from trauma, disease or age.

It is a combination of engineering with developmental biology and involves the application of various materials and cells to contribute to the healing of tissue or the replacement of deteriorated tissue, either structurally or functionally. Such methods show particular promise in regenerating or replacing a variety of organs, including skin, heart, kidney and liver¹.

Transplantation remains the method of choice for repairing or replacing non-functional or severely damaged organs. However, supply of donated tissues and organs cannot keep up with increasing demands, fueling the need for alternative approaches.

Today, perhaps the best-known branch of regenerative medicine is cell therapy, illustrated by stem cell research. This involves the manipulation of undifferentiated cells in order to control their development into a certain cell or tissue type. This research has gained notoriety due to its use of stem cells extracted from embryos. However, adult-derived stem cells, such as cancer cells or cells from bone marrow, are much more commonly used due to their ready availability and perceived safety².


Examples of approved regenerative therapies

Several regenerative therapies, both cellular and non-cellular, have already received approval from regulatory bodies to be used in humans for a variety of indications, including wound, muscle and bone healing.

Some of these are illustrated below. Many more are currently being assessed in clinical or pre-clinical trials.

Cell-based
immunotherapy

Various cancers
Graft vs host disease

Gene therapy
products

Melanoma surgery skin lesions
Critical limb ischemia
Muscular dystrophy
Retinal dystrophies

Cell therapy
products

Connective tissue disorders,
(including cartilage, defects,
Burns, Type 1 diabetes,
Spinal cord injury)

Tissue-engineered
products

Bone and cartilage defects
Cardiovascular abnormalities
Wound treatment
Skin disorders
(including burns, scars)

Currently, the greatest challenge of regenerative medicine is not only stem cell differentiation, isolation or lineage diversity, but also ensuring the cells integrate correctly into the target defective organ, as well as any necessary blood circulatory and nervous systems³. For this reason, a great deal of research is being carried out into the bioprinting of physical scaffolds, with various integrated biological factors, such as cells or growth factors.

3D bioprinting techniques have been used to create functional heart valves and even beating cardiac tissue. The transplantation of such patches has been used to successfully improve infarcted hearts. In addition, micro-livers have already been fabricated which allow the high-throughput study of various drug candidates. Such techniques also show great potential in other research areas such as oncology and drug toxicity³.


References:

  1. Mao AS, Mooney DJ. Regenerative medicine: Current therapies and future directions. Proc Natl Acad Sci USA. 2015;112:14452-14459.
  2. Mironov V, Visconti RP, Markwald RR. What is regenerative medicine? Emergence of applied stem cell and developmental biology. Expert Opin Biol Ther. 2004;4:773-781.
  3. Dzobo K et al. Advances in Regenerative Medicine and Tissue Engineering: Innovation and Transformation of Medicine. Stem Cells Int. 2018;2018:2495848.