Background

Cell therapy can be defined as therapy in which cellular material is injected or otherwise transplanted into a patient. The origins of cell therapy can perhaps be traced to the nineteenth century, when Charles-Édouard Brown-Séquard (1817–1894) injected animal testicle extracts in an attempt to stop the effects of aging. In 1931 Paul Niehans (1882–1971) – who has been called the inventor of cell therapy – attempted to cure a patient by injecting material from calf embryos. Niehans claimed to have treated many people for cancer using this technique, though his claims have never been validated by research.

In 1953 researchers found that laboratory animals could be helped not to reject organ transplants by pre-inoculating them with cells from donor animals; in 1968, in Minnesota, the first successful human bone marrow transplantation took place. In more recent work, cell encapsulation is pursued as a means to shield therapeutic cells from the host immune response. Recent work includes micro-encapsulating cells in a gel core surrounded by a solid, but permeable, shell.

Bone marrow transplants are the most common and well established cell transplantation therapies. The first recording of a successful bone marrow transplant, dates back to 1956 by dr. E Donnall Thomas, who treated a leukemia patient with their twin-siblings bone marrow. In general, for patients presenting damaged or destroyed bone marrow, for example after chemotherapy and/or radiation for acute myeloid leukemia (AML), bone marrow derived cells can be infused into the patients blood stream. Here the injected cells are able to home into the afflicted bone marrow, integrate, proliferate and recover or re-establish its biological function e.g. the haematopoiesis. Annually an estimated 18,000 patients require potentially life-saving bone marrow transplants in the USA. For a long time, bone marrow transplantation was the only clinically applicable method of cell transplantation, however, since the 1990s, cell therapy has been investigated for a wide scale of pathologies and disorders. Cell therapy provided a novel approach to effectuate therapeutic efficacy. Previously, medical agents could only be effective by directing and inducing the patients own cells. However, in many diseases and disorders, cell are compromised by e.g. senescence, limited blood supply (ischemia), inflammation, or simply a reduction in the number of cells. Cell therapy offers a new strategy that supports the introduction of new and active cells to restore previously compromised or deteriorated tissue- and organ structures. As such, in recent times, cell therapy has been recognized as an important field in the treatment of human disease, and investigations are ongoing in articular cartilage, brain tissue, spine, heart, cancers, etc. As a consequence cell therapy as a strategy has been attracting significant investments by commercial entities which suggest strong prospects for future growth.