The success of tissue engineering for cartilage for conditions like
osteoarthritis will be dependent on the interactions between the cells, the
matrix, and mechanical forces directed against the joint.
The extracellular matrix the framework and the material inside the framework
the stem cells cling to plays a crucial role in tissue function, dictating its
physical and mechanical properties, maintaining the spatial arrangement of the
cells that live within it and controlling the complex crosstalk that exists
between the cells, the matrix and external forces. The matrix controls cell
size, shape, movement and alignment through its three dimensional architecture
and adhesion the stickiness of the stem cells.
While the matrix exerts its effects, the cells influence the matrix by
applying traction forces and by synthesizing and degrading matrix. In addition,
the interaction between the matrix and stem cells is responsible for triggering
a variety of specific cellular functions. It has become increasingly clear that
the mechanical environment is equally important as, and synergistic with, the
chemical environment in directing cell behavior.
Signaling pathways spurred on in response to mechanical (load bearing) forces
are essential for the maintenance and function of tissue cellular function. Load
bearing soft tissues such as tendons and cartilage which consist of a network of
fibrous protein (predominantly collagen and elastin), embedded in a gel of sheet metal welding suppliers
proteoglycans, glycosaminoglycans and glycoproteins exhibit specific properties
of tissue biomechanics and subsequent cellular responses.
Investigations in these unique tissues and engineered are rapidly expanding
our understanding of a new area of medicine called mechanobiology.
Successful tissue engineering requires a comprehensive understanding of
mechanobiology and in particular the loading conditions experienced by the cells
under physiological conditions, in order to establish how this controls cellular
Clarification of mechanical pathways should provide useful information for
tissue engineering and regenerative applications as well as further insight into
mechanisms involved in disease processes.
The population of the Western world is aging. As a direct consequence, there
will be an increase in diseases that can be associated with aging, such as joint
problems.. Those maladies not only have a negative effect for the patient, but
will also have a significant impact on the health care system. Therefore, it is
extremely important that more active, less traumatic and less expensive methods
and techniques are developed for the treatment of these diseases. The
expectation is that nanotechnology will provide an important contribution to the
development of such techniques. Implants and tissue substitutes are made from
biomaterials that have one common property, i.e. biocompatibility. A promising
application of nanotechnology is the development of better functioning
A recent approach to the design of next generation tissue regeneration
supporting biomaterials is focusing on the structure at the nano scale. The
underlying idea is that nanometer structure matches with the natural
extracellular matrix resulting in an improved interaction of the tissue forming
cells compared with conventional biomaterials. Recent developments in the field
of nanotechnology offer powerful tools to modify the surface of biomaterials by
introducing artificial mapping and specific surface chemistry on the material.
It is well known that both topography and surface chemical composition affect
the reactions of the biological environment to the device.
Human mesenchymal stem cells occupy a particular stem cell niche, and consist
of those stem cells that can differentiate into cells of mesenchymal tissues,
including osteoblasts, adipocytes and chondrocytes.
Osteoarthritis is the most common musculoskeletal disorder and causes a
significant social and psychological drain on those affected as well as those
who care for them; in addition it leads to significant economic costs. This
disease is characterized by articular cartilage degeneration and damage to the
underlying subchondral bone. To date, there is a lack of effective therapies to
treat the disease, resulting in total joint arthroplasty (joint replacement
surgery) as the only viable therapeutic option. Thus, there is a need to develop
methods that are less invasive and capable of regeneration of articular
The use of autologous chondrocytes in tissue engineering applications
promises an avenue in terms of efficacy and safety resulting in mesenchymal stem
cells (MSCs) being considered an ideal therapeutic candidate for cartilage
repair. MSCs acting through multiple growth mechanisms are also known to prevent
OA progression after injection into the joint.
At our center, we are constantly incorporating newer approaches to the
introduction of stem cell technology for the treatment of osteoarthritis.
Our approach now is different from the way it was a year ago... and it will
be different a year from now as we learn more about nanobiology.