Prof. Dr. Michael Nerlich: Future of biomedicine – Biomaterials for regenerative medicine

The modern ageing society poses new challenges for medicine. For instance, the demand for medical practices which regenerate worn out tissue is increasing, amongst other things, for individuals to lead a healthy life at old age. Biomedicine in Bavaria is at the forefront of this research field.

 

Regenerative medicine is an innovative, but also complex biomedical area of expertise, in which great hopes have been placed. Stem cell research, gene therapy and tissue engineering, i.e. cul­­tivation of tissue and cell complexes, promise good chances of recovery when fighting severe and incurable diseases such as cardiac, autoimmune and neurological diseases, paraplegia and Par­­kinson’s disease, chronic inflamma­­tory diseases, diabetes, solid tumours, leukaemia, bone and cartilage diseases or defects and skin transplants. Regen­­era­­tive medicine is already successfully applied in cases of leukaemia and joint cartilage defects.

At the “MedTech Pharma 2012 – Medizin Innovativ” con­­gress of the MedTech Pharma e.V. forum in 2012, a sep­­arate range of topics with renowned speakers was dedi­­cated to biomaterials. A large number of experts in this field of ex­­per­­tise were brought together in the Free State of Bavaria.

Regenerative medicine research working full steam ahead. Life expectancy keeps increasing and at the same time, more people are exercising regularly. This leads to an increased demand in meth­­ods of regenerating worn out tissue. Tissue engineering is a central tech­­nol­ogy of regenerative medicine and biomaterials are the material base. Cells for establishing new tissue structure require an appropriate architecture (scaffolds) for successful growth. A promising approach are the bio­­active glass scaffolds developed by Prof. Dr. Aldo Boccaccini from the Er­­lan­gen-Nurem­­berg uni­­versity. Biopol­­y­mers with non-organic nano fibre par­­ti­­cles coat and infuse the scaffolds, thereby making them more resistant to frac­­tures. Sol­­uble products from glass influence osteo­­genesis and angiogenesis, i.e. the for­­­ma­­tion of bones and vessels. Nano structures improve cell adhesion and cell growth.

 

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An example of how important organ func­­tions can be re­­stored using tissue engineering is the removal, cultivation and reinsertion of contractile myocardial tissue. With this method, Dr. Andreas Hilfiker from the Han­nover Medical School (MHH) aims to prevent irreparable defects of this tissue due to loss of oxygen and nutrients supply in the car­­diac tissue. The regeneration potential of the cardiac tissue cells is so low that the lost functionality cannot regenerate out of its own. As Prof. Dr. Jürgen Mollenhauer explained to the auditorium, this proce­­dure has been working quite well for sev­­eral years on auto­logous cartilage cell transplant of joint cartilage. Carti­­lage cells are taken from the patient, propagated in cell culture and implanted back into the damaged area, where they can rebuild cartilage tissue. However, problems have ap­­peared recently from the regulatory side, as the effective therapy is now classified as being a regulatory pharmaceutical with all time high in time and cost consequences.

The BioTissue Technologies GmbH has developed two solu­­tions for the therapy of cartilage defects: on the one hand, a cell-based product from patients’ own cells and a poly­­mer-based absorbable carrier matrix. On the other hand, an implant from a cell-free and stable 3D carrier matrix. The bone marrow stimu­­lating process is intensified by sup­­port­­ing the body’s own regeneration potential by attract­ing stem cells to the location of the cartilage defect.

A number of new therapeutic options, especially for cardio­­vascular diseases, are opend by highly bio-compatible, innovative silk fibres. A special spider imita­­­ted manu­­facturing process of silk enables the textile processing of the bio­­material, for example for small-diameter vascular prostheses. Robin Ross and colleagues from the RWTH Aachen is developing the optimal structure and coating so that artificial blood vessels become flexible and blood-tight.

The basis for regenerative medicine is especially adult stem cells and precursor cells from bone marrow and peripheral blood. However, cells with desired prop­­erties have to be sep­­arated from those with undesired effects. The cell separation method of Miltenyi Biotec GmbH is based on the connection of magnet par­­ticles on antibodies. Finally, the cells are ana­­lysed using specific reagents, as described by Volker Huppert.

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Outstanding things can be achieved with patience and ingenuity. For example the successful creation of human tissue with cell-based 3D techniques and reconstruc­­tion of structures of defected organs and body parts. It was a long way to achieve this goal, which took almost two decades. Although it was and still is a brilliant idea, there are central factors and challenges to it such as vascularisation of vessels and carrier materials (scaffolds).

In order to grow replacement fibrosis from the body’s own cells, such as cardiac valves, different materials are col­o­­nised with human cells. Depending on the pur­­pose, poly­­mers, calcium phosphate, ceramics, gels or in special cases also bowel explants are used. The leading researchers in the field of regenerative medicine and biomaterials are Professor Dr. Heike Walles, chair Tissue Engineer­­ing and Regenerative Medicine at Würz­­burg university, and Pro­­fessor Dr. Aldo Boccaccini, chair and head of the In­­sti­­­­tute of Biomaterials at Erlangen-Nurem­­berg university. As basis for transplants for trachea reconstruction, Heike Walles uses a very specific medium for a scaffold. Together with her work group and the Schillerhöhe clinic, she succeeded in developing a transplant with its own vas­­cular system for clinical use. A se­­vere­­ly injured patient with a burned oesoph­­agus could be healed using this transplant.

As biomaterial for the reconstruction of body tissue, calcium phosphate ceramics provide a highly diverse range of appli­­cations. They are useful for both bone re­­placement material and tissue engineering. Since the scaffold material is very similar to natural bones in terms of its chemical composition, it has proven to be highly bio-compatible. The produc­­tion of scaffolds is carried out by different rapid prototyping procedures, which were optimised by the work group of Ulrike Deisinger from the Friedrich-Baur re­­search institute for biomaterials at Bayreuth University.

Ulrich Nöth, a physician and scientist at the Orthopedic Centre for Muscu­­lo­skel­­e­­tal Research (OZMF) at Würzburg Uni­­ver­­sity, and his work group Tissue Engi­­neering are inves­­tigating tissue re­­generation of cartilage and bones. Nöth prefers collagen-based gels as carrier material for cartilages. In the case of larger bone defects, much depends on how stable and how absorbable the carrier materials are. In various clinics research is also perfor­med on regenerative treatment op­­tions for diabetes mel­­litus type 1, for example at the clinic f­or paediatric and ado­­lescent med­­icine (Klinik für Kinder- und Jugend­­medizin) in Munich. Although promising approaches have been devel­­oped, a matured therapy has not yet been implemented.

The methods of regenerative medicine offer great po­ten­­tial, which is also being recognised by more and more inves­­tors. Further funding is required to make these modern therapies available to more pa­­tients, especially due to the high ap­­proval expenses that are hardly affordable for many small and medium-sized businesses.

 

Nerlich_Michael_originalThe author was born in Landshut in 1953 and studied human medicine at LMU in Munich. After having worked at the MHH Hannover, in the United States and Swit­­zerland, Prof. Dr. Nerlich has been head of the Trauma Surgery department at Regensburg Uni­­versity Hospital since 1992. He is president of the International Society for Tele­­medicine and chairman of the Forum Medtech-Pharma e.V.