Human stem cells are the immature cells that give rise to all of the different types of mature cells that make up the organs and tissues of the adult body. The transition from stem cell to mature, specialised adult cell is called 'differentiation'.
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Stem cells in the body take different pathways of differentiation in response to different stimuli from their environment. Similarly, stem cells in the laboratory can be stimulated to differentiate along different pathways by exposing them to various combinations of biochemicals.
Stem cells can be coaxed into becoming, among other tissues, blood cells, bone, cartilage, fat, blood vessels or heart muscle.
The discovery of this property prompted researchers to look for ways that stem cells could be used as the basis of treatments to repair and re-grow a range of tissues and organs. |
Stem cells exist in the embryo and also in adult tissues such as bone marrow, fat, skin and dental pulp, though in much smaller relative numbers than in the embryo. The two types of adult stem cells are haematopoietic, which give rise to new bone marrow and blood cells, and mesenchymal, which give rise to solid organs and tissues, such as bone, heart, and cartilage.
Haematopoietic-type adult stem cells can be readily obtained from bone marrow and are already being used clinically after high-dose chemotherapy to treat patients with certain types of cancers.
Technology related to mesenchymal-type adult stem cells is much less developed due to the difficulty of obtaining sufficient numbers of these cells and of growing them in the laboratory.
The proprietary technology being commercialised by Mesoblast enables efficient extraction, isolation and scale-up of mesenchymal-type adult stem cells called mesenchymal precursor cells (MPC). This technology relies on the identification of unique markers on the surface of the MPC to which monoclonal antibodies bind, enabling the extraction of MPC from the mixture of cells in their resident tissues.
Some of the advantages of the proprietary MPC technology over other adult stem cell technologies are:
Precise identification and ease of isolation
Other methods for isolating stem cells from tissues generally rely on their physical properties, such as large size. However, no physical properties are specific to mesenchymal-type adult stem cells, so the methods yield a mixed population of cells.
Mesoblast's technology gives a cell population containing up to 1000-fold greater concentrations of MPC than those achieved by conventional methods of isolation. Higher proportions of MPC mean more effective therapy and lower production costs.
Ease of expansion and scale-up
Most adult stem cells cannot be efficiently expanded in culture. In contrast, MPC can be activated to grow and divide rapidly via special receptors on their cell surface that are bound by growth factors present in the culture conditions used by Mesoblast as part of its proprietary process.
Wide-ranging potential applications for diseases
with unmet clinical needs
Due to the ability of MPC to regenerate mesenchymal tissues such as bone, cartilage, arteries, and heart muscle, Mesoblast's technology will provide cells with the potential to treat a wide range of conditions requiring tissue regeneration. Mesoblast will concentrate on treatments for bone fractures, osteoarthritis of joints such as the knee, and vertebral disc disease, and its partner, Angioblast, will concentrate on MPC-based treatments for heart and blood vessel diseases.
MPC do not cause immune rejection, may be used in unrelated recipients
MPC from a given donor do not activate immune cells from unrelated recipients. This property is likely to enable Mesoblast to generate a range of “off-the-shelf” MPC products from universal donors, simplifying the process and costs of batch quality assurance/quality control testing, reducing cost-of-goods, and increasing product margins. It is anticipated that MPC-derived products from allogeneic, or unrelated, donors will be available to the clinician on demand, and used in a similar way as any pharmaceutical product.
Advantages over embryonic stem cells and absence
of ethical issues
Mesoblast's MPC technology also has at least four advantages
over embryonic stem cell technologies. These are:
• absence of ethical concerns
• fewer steps needed for tissue differentiation since already at more
mature stage of development
• lower risk of cancer formation
• lack of recognition by recipient's immune system and possibility of use in unrelated recipients.
The Technology
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