The future lies in the cell
Articular cartilage transplant increases quality of life
Never say never. The James Bond maxim particularly applies to medical research. Just a few years ago, it was impossible to grow articular cartilage tissue to repair cartilage damage in knee and ankle joints resulting from sports injuries or accidents by transplanting the body's own tissue. Researchers today already have their sights set on the intervertebral disc. More than 200 million people worldwide suffer from diseases of the skeletal system. Approx. 1.85 million people in the US and Europe undergo arthroscopic surgeries each year and 350,000 endoprostheses are implanted alone. Implants are always associated with the risk that the patient's body will reject the artificial structure as a foreign body. To prevent this from occuring, the patient must take drugs, often for life. In young patients, there is also the risk that the implant could wear out over time and may have to undergo another operation. With this in mind, two trauma surgeons founded a company in 2000 in Reutlingen, Germany. Their goal? To replace implantation by transplantation, i.e. the transfer of the body's own tissue, especially in young people. Transplants eliminate the risk of rejection. The natural healing powers of the body support the healing process. Both founders named their company Tetec – TE for Tissue Engineering and TEC for innovative technology. Tetec AG is a subsidiary of Aesculap AG of Tuttlingen, Germany. From the first three employees, the company has become an interdisciplinary 30-man team and is growing very successfully.
Healing through the body's own tissue replacement: Hyaline cartilage
A speciality of Tetec is the growth of hyaline cartilage as a transplant for injuries to the knee and shoulder joints. Hyaline cartilage forms a protective layer on the articular bone. At the contact point of the bone, it absorbs the contact and functions as a virtual shock absorber. To date, there has been no artificial material that can achieve the elasticity, compressive strength and resistance to friction of natural cartilage. The problem lies in the fact that articular cartilage cannot regenerate or regrow itself after damage due to injury. In the long run, complaints arise, so that the patient has to anticipate long-term arthritis and joint stiffness and artificial joint replacement. Until now, there have been two options to treat small defects surgically. In the case of microfracturing, fractures are created in the bone under the defect. Blood bone marrow and stem cells can then penetrate through the opening and fill the defect with scar tissue. However, the new tissue is not the same as the original cartilage and is, for example, far less resilient. In the case of another procedure, mosaicplasty, cartilageor a cylindrical graft is taken from a healthy joint and transplanted into the defective area. The advantage of this procedure is that a large part of the defect can be treated with the body's own cartilage tissue. However, less resilient scare tissue forms in the gaps between the cylindrical grafts. In addition, the procedure can lead to arthritis in the area where the grafts were taken if too many are taken. All of these disadvantages are eliminated in the case of cartilage cell transplantation such as Tetec has developed and offers in Europe.
Speed, safety and perfection – cartilage cell transplantation
In principle, three steps characterize the process of regenerative medicine: At first, a small amount of tissue is taken from the tissue. From this tissue, the body's own cells are cultures and ultimately transplanted back into the patient. What sounds so simple is a thoroughly planned process of high precision. Aesculap AG in cooperation with Tetec conducts special training to prepare physicians in the surgical part of the procedure. In an initial operation, the physicians take two approx. 4 mm cylindrical grafts next to the actual defect from the patient consisting of bone and cartilage. The grafts are placed in a special transport solution and and sent to Tetec in temperature-controlled transport boxes. The time between harvesting the grafts and arrival at Tetec is no more than 24 hours domestic / 48 hours international. The validated system ensures the most gentle transport as possible. As soon as the samples arrive at Tetec, a catheter sheath system puts the samples into the highest cleanroom class. Staff prepare the cells samples in insulators. The cell content in the samples taken is about 3%, i.e. 10,000 to 50,000 cells. Within three weeks, 20 million cells are grown in the CO2 incubator.
Help through quality engineering
Tetec uses CO2 incubators from BINDER GmbH of Tuttlingen, Germany. "BINDER CO2 incubators reliably provide the conditions absolutely required for cell cultivation. We need 37 °C and 5% CO2 for optimal cell growth. Each tenth of a degree counts because every degree more endangers the cells. They get a "fever" and at worst, are killed. For the patient, that would mean undergoing the entire procedure again. For this reason, reliability and precision of the CO2 incubators are so important for us," explains Dörte Keimer, director of the Tetec Laboratory. 23 CO2 incubators of the proven CB 210 series are in the lab, seven more in the building. They have been customized with 9 instead of 6 segment doors. In the 9 compartments, the cell material for each patient can be housed separately. Cleanroom is expensive. The stackability of the units was an important factor for Tetec because the scope of work is constantly growing. The particularly good insulation of the CO2 incubators make this possible. Even hot air sterilization at 180 °C has no effect on the climate in the adjacent chambers. Hot air sterilization is performed once a month. "It makes cleaning that confirms to standard very simple," praises Dörte Keimer. Sterility is always top priority. "We have never yet had any contamination." A new scanning system ensures that samples are not inadvertently mixed up and that each patient receives his or her own tissue. The "four-eye system" enhances the technology: two team members always work together. "We are a manufacturer – and that ensures maximum safety," according to Tetec. If enough cells are cultured in three weeks, they are packed onto carrier material. This membrane has been specially developed for Tetec. In the OR, the graft is placed in the sterile transport containers and into the validated transport system. The physicians can then cut and use the graft on site. The timing is precisely coordinated that the second operation can be performed on the same weekday as the first – many physicians have in-patient beds in hospitals and controlled OR days.
Sights set on the intervertebral disc
In research, Tetec AG works with cooperation partners in clinical, university and industrial areas. The goal is to further develop biological cartilage reconstruction where the intervertebral disc is of particular interest. In November 2008, Tetec moved into a new state-of-the-art building with "growth" in mind. Tetec is supported by its parent company Aesculap AG. BINDER GmbH supplies state-of-the-art CO2 incubators and as needed, customized systems for optimal cell growth.
