Future of Bone Regeneration
The Medical Research Council Bone Research Unit under Prof Ugo Ripamonti has
made great strides in bone regeneration therapy. Below follows a summary of
their invention. For the detailed article, link here.
 It’s
long been known that bone is quite good at repairing itself, but if the injury
is beyond a critical limit, it cannot heal by regeneration. This is where
therapy can make the difference.
A major advantage in the understanding of bone formation and regeneration has
been the identification of an entirely new family of protein initiators, the
bone morphogenetic proteins (BMPs). The BMPs regulate cartilage and bone
differentiation in the body.
The BMPs initiate bone formation and if applied to a bone defect, will
initiate bone formation and growth where it is required. How does this work?
Since the BMPs are proteins, they require a specific cell-surface receptor to
initiate an action. Once it finds and binds to a target receptor, a ripple-like
cascade of events is initiated inside that cell. DNA in the cell’s nucleus
becomes activated and order other structures within the cell to begin producing
gene-products that induces the cell to transform and eventually to become cells
which synthesize cartilage and bone matrix, cells that make cartilage and bone
i.e. chondroblasts and osteoblasts.
BMPs induce endochondral bone differentiation through a cascade of events
which include formation of cartilage, hypertrophy and calcification of the
deposited cartilage, vascular invasion, differentiation of osteoblasts and
formation and mineralization of bone.
The BMPs need a carrier matrix to deliver their biological activity to where
it is needed to induce bone formation. Without the carrier matrix acting as
delivery system, the regenerating action of BMPs is lost.
Different matrices can be used to deliver the osteogenic activity of BMPs.
The most widely used so far in pre-clinical and clinical trials has been the
collagenous bone matrix, a collagenous preparation obtained after extraction of
BMPs from the bone matrix.
A major goal of the Medical Research Council’s Bone Research Unit directed
by Professor Ugo Ripamonti has been the identification of inorganic,
nonimmunogenic carriers with correctly defined geometries capable of delivering
BMPs, particularly without collagenous matrix as carrier.
The team has made important contributions in this field of tissue engineering
particularly by developing a hydroxyapatite-based bioceramic material which acts
as an optimal matrix for delivering the biological activity of BMPs.
The bioceramic material consists of highly crystalline hydroxyapatite which
has a natural binding affinity for the BMPs. Adsorbing the BMPs to this material
restores the biological activity of these proteins.
When using these hydroxypatite implants, the critical step in the initiation
of bone formation is to provide the right geometry, a concavity that mimics the
environment that traps the BMPs at the interface of the hydroxyapatite with the
invading soft fibrovascular tissue.
It is very important to note that this inventive method does not require the
exogenous application of BMPs, which will be rather expensive once approved by
government’s agencies, but rather relies and uses the BMPs circulating and
locally produced by the very patient's.
The Bone Research Unit has thus developed and patented a successful
bioceramic material capable of initiating bone regeneration per se and in
addition it has patented an osteogenic delivery system using liquid
chromatography to adsorb BMPs onto a variety of carriers.
According to Professor Ripamonti, bone deposition and growth can be initiated
within 30 days using the patented hydroxyapatite matrix. This innovation may
soon be a treatment reality for bones damaged during trauma or in bone
degenerative illnesses.
The expertise of the Bone Research Unit is poised to make significant
contributions in tissue repair, regeneration and morphogenesis which are of
relevance to Southern Africa and the rest of the world.
Prof Ripamonti provides a detailed understanding of the challenges and successes
in bone regeneration research. Please link here for the main article.
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