Regenerative Medicine: Successes, But No Miracles

The public’s expectations of regenerative medicine are great. Some could be fulfilled, others not. 

Hardly any other field within biomedicine has developed so rapidly in the last ten years and is associated with such high hopes as that of regenerative medicine. “Thyroid gland bred for mice” or “Nose cell transplant enables paralysed dogs to walk” – these are just some of the headlines of the past months. Common to all the research approaches described is the motto: regenerate instead of repair.

Indeed, the potential of regenerative medicine is great. But its path into medical care is long. Scientists stated that the vision of simply being able to rejuvenate diseased organs is far from reality. Regenerative medicine has been marked by many successes in recent years, but also by setbacks.

Deficits in skin replacement

In clinical practice, regenerative procedures have already been used for skin, cartilage or heart. But while ten years ago the transplantation of adult stem cells was considered a very promising application of stem cells to improve heart function after a heart attack, large clinical studies have meanwhile put this hope into perspective again.

The situation is similar for skin replacement: Despite intensive research, tissue engineering of human skin has so far disappointed. Despite minor successes, it is not yet possible to prevent the formation of scars, to regress existing scars or to pigment the “new skin”, said the surgeon. He sees future regenerative approaches in treatment with suspensions containing the patient’s mesenchymal stem cells, but also in combination with biophysical therapies.

But there are also success stories: Haematopoietic stem cell transplantation is now considered a standard therapy that saves lives in many leukaemias and lymphomas. “We have now learned that the interaction of the stem cells with the so-called stem cell niches determines the fate of the stem cells such as self-renewal, differentiation and ageing. 

To break the bond between stem cells and the niche, reagents such as Plerixafor are used nowadays, he said, which ensure that the haematopoietic stem cells leave their niche in the bone marrow and are flushed out into the blood, where they can be harvested for transplantation purposes. 

Plerixafor is now approved for stem cell harvesting and represents a good example of the achievements of mechanism research in the development of stem cell technologies. 

However, it took more than 20 years for stem cell transplantation for blood cancer to gain worldwide acceptance as a standard therapy, and another ten years for the treatment to be recognised by insurance providers, the oncologist pointed out: Realistically, we are only at the beginning of a long road in stem cell research for regenerative medicine.

Immune modulation possible

We reported on immunomodulatory procedures for the adjuvant therapy of type 1 diabetes mellitus. 

Children are currently being treated with cells from the blood of their own umbilical cord as part of a study by her research group. It contains a lot of cells that can correct the wrong reaction of the immune system. Whether the therapy will work in the long term, however, cannot yet be assessed.

So far, however, the children have tolerated it well; it does not cause side effects. “The study is an important further step on the way to understanding tolerance induction in autoimmune diseases we emphasised.

Assured the scientists of the support of politics in their research. There is no alternative to a policy that focuses on research, development and innovation

The scientists need support from the legislator, for example, with regard to biobanks. We have to protect the individual rights of donors in the legal regulation of biobanks and at the same time promote research. 

It is problematic that in addition to some large biobanks, there are still about 10,000 small projects for which the same strict regulations are applied as for the large biobanks. The researchers therefore plead for graduated regulations.

Regenerative medicine the alternative

The aim of regenerative medicine is not to replace joints but to reconstruct them. Two paths can lead to the goal: the regeneration of a tissue can take place outside (in vitro) but also inside (in vivo) the human body.

In orthopaedics, tissue replacement of destroyed joints with adult stem cells within the framework of regenerative medicine is an innovative therapy option. Only a few centres, such as Orthopaedics, have the highly specialised knowledge to be able to use the therapy option of differentiating adult stem cells.

Human mesenchymal stem cells (hMSCs) are extremely versatile cells from the bone marrow and have the potential to differentiate into various tissue cells. Stem cells are harvested from the patient’s iliac crest without opening the joint. 

This operation is significantly less risky than a second joint operation. hMSCs represent a cellular alternative for autologous transplantation due to their proliferation behaviour and differentiation ability. 

Differentiation is stimulated by the addition of growth factors. In the field of regenerative medicine, the question is therefore increasingly being asked whether the use of mesenchymal stem cells represents a sensible alternative for covering cartilage, bone and tendon defects.