Autologous growth factors or AGF is a technology that uses the patient’s own platelets as a source of growth factors. The platelets are super concentrated and then de-granulated to release mitogens, such as TGF-beta, PDGF, IGF, FGF and VEGF. AGF can be used alone as a source of signaling factors or it can be used with a variety of bone grafting materials, including autograft, allograft or porous ceramics. AGF is advantageous because it is completely autologous and obtained at the point of care in the operating room. AGF has been shown to be successfully collected by pheresing or separating the whole blood into its components to capture the buffy coat (i.e., platelets and white cells) using a conventional cell washer. To assure a predictable two to four fold increase in platelets and white cells over the peripheral blood concentration, the operator of the cell washer must follow a defined protocol. The buffy coat is then transferred to a processor containing an ultra concentrator. This achieves a further three fold concentration of platelets and white cells, as well as a three fold concentration of fibrinogen. This process can be effectively achieved using a single unit (approximately 450cc) of blood which produces approximately 60cc of autologous growth factors (AGF). The excess plasma and red cells can be returned to the patient.

We have developed as self-contained, electromechanically, software driven, turnkey device that separates and concentrates to produce AGF from as little as 100 cc of the patient’s whole blood. The device is the size and weight of a portable, tabletop clinical centrifuge. A single disposable, pre-sterilized cartridge is inserted into a centrifuge and automatic pumps. After the operator attaches the blood bag and provides minimal input, the machine automatically provides 10–15 ml of AGF. Total processing time is less than 15 minutes. Multiple, simultaneous cycling can process up to 450 ml of blood with operating times comparable to our contemporary system. Using human blood, the concentrations of platelets, white cells, and fibrinogen was comparable to the contemporary system. The AGF platelets were then de-granulated into a fibrin gel using either xenogenic or autologous thrombin. Consequently, the concentrations of TGF-beta, PDGF, IGF, FGF and VEGF were approximately 10 fold greater than blood levels and comparable to the separate component system.

We believe that we have developed a method and device that safely, simply, cost-effectively produces intra-operatively clinically relevant levels of autologous growth factors from 100 ml of autologous blood.

Tissue engineering is founded on the principle of pro-actively manipulating the triad of tissue regeneration. The triad consists of matrices, pluripotential cells and signaling factors. Our hypothesis is that advances in orthopedic surgery to successfully regenerate bone are accomplished by incorporating optimised matrices into the surgeon’s armamentarium.

Pro Osteon is a bioactive ceramic matrix with interconnected porosity. It has been evaluated in experimental animals and used clinically as a bone graft substitute for more than two decades. It is available in slowly resorbable form composed of hydroxyapatite and as a more rapidly resorbable composite of calcium carbonate and calcium phosphate. Experiments have been conducted in sheep, rats and dogs to demonstrate consistent and predictable bone regeneration when the implant is placed in direct apposition to host bone, the host bone is viable and the interfaces between the bone and implants are biomechanically stable. Most importantly, controlled, multi-center clinical trials showed consistent efficacy and safety in humans. Either as a block or granules, Pro Osteon is biocompatible and osteophilic and osteoconductive. Bone regeneration, as demonstrated radiographically and histologically, occurs directly within the porous ceramic in traumatic defects and tumors. Where surrounding viable bone or mechanical stability is inadequate, such as posterior spinal fusion, the ceramic must be co-mixed with autograft. For indications where autograft is limited or unavailable, bone regeneration within the porosity was enhanced and fusion achieved by supplementing Pro Osteon with bone marrow and/or with growth factors. This was demonstrated experimentally and clinically. Mitogenic and/or morphogenic growth factors were demonstrated to increase the rate or degree of bone formation. Methods and equipment for intra-operative collection of concentrated platelets were shown to be a cost-effective and safe source of autologous mitogens. Using a variety of ectopic and orthotopic animals models, we have shown that autologous, purified xenogenic and recombinant growth factors will bind to the surface of Pro Osteon and initiate or stimulate the bone induction process.

In conclusion, Pro Osteon is an effective matrix for bone formation. It can be used alone or it can be used in combination with pluripotential, osteogenic stem cells or with signaling proteins.