Distraction osteogenesis of the lower extremity in patients with achondroplasia/hypochondroplasia treated with transplantation of culture-expanded bone marrow cells and platelet-rich plasma

Enhancement of bone formation during distraction osteogenesis: pediatric applications

Delayed bone healing during distraction osteogenesis negatively affects clinical outcome. In addition to autologous bone grafting, several mechanical, chemical, biologic, and external treatment modalities may be employed to promote bone growth during distraction osteogenesis in the pediatric patient. Mechanical approaches include compressive loading of the distraction regenerate, increased frequency of small increments of distraction, and compression-distraction. Intramedullary nailing and submuscular plating can reduce the time in external fixation; however, these techniques are associated with technical difficulties and complications. Exogenous application of low-intensity pulsed ultrasound or pulsed electromagnetic fields may shorten the duration of external fixation. Other promising modalities include diphosphonates, physician-directed use (off-label use) of bone morphogenetic proteins, and local injection of bone marrow aspirate and platelet gel at the osteotomy site. Well-designed clinical studies are needed to establish safe and effective guidelines for various modalities to enhance new bone formation during distraction osteogenesis in children.

Skeletal stem cells and bone regeneration: Translational strategies from bench to clinic

Clinical imperatives for new bone to replace or restore the function of traumatized or bone lost as a consequence of age or disease has led to the need for therapies or procedures to generate bone for skeletal applications. Tissue regeneration promises to deliver specifiable replacement tissues and the prospect of efficacious alternative therapies for orthopaedic applications such as non-union fractures, healing of critical sized segmental defects and regeneration of articular cartilage in degenerative joint diseases. In this paper we review the current understanding of the continuum of cell development from skeletal stem cells, osteoprogenitors through to mature osteoblasts and the role of the matrix microenvironment, vasculature and factors that control their fate and plasticity in skeletal regeneration. Critically, this review addresses in vitro and in vivo models to investigate laboratory and clinical based strategies for the development of new technologies for skeletal repair and the key translational points to clinical success. The application of developmental paradigms of musculoskeletal tissue formation specifically, understanding developmental biology of bone formation particularly in the adult context of injury and disease will, we propose, offer new insights into skeletal cell biology and tissue regeneration allowing for the critical integration of stem cell science, tissue engineering and clinical applications. Such interdisciplinary, iterative approaches will be critical in taking patient aspirations to clinical reality.

Alternative sources of adult stem cells: human amniotic membrane

Human amniotic membrane is a highly promising cell source for tissue engineering. The cells thereof, human amniotic epithelial cells (hAEC) and human amniotic mesenchymal stromal cells (hAMSC), may be immunoprivileged, they represent an early developmental status, and their application is ethically uncontroversial. Cell banking strategies may use freshly isolated cells or involve in vitro expansion to increase cell numbers. Therefore, we have thoroughly characterized the effect of in vitro cultivation on both phenotype and differentiation potential of hAEC. Moreover, we present different strategies to improve expansion including replacement of animal-derived supplements by human platelet products or the introduction of the catalytic subunit of human telomerase to extend the in vitro lifespan of amniotic cells. Characterization of the resulting cultures includes phenotype, growth characteristics, and differentiation potential, as well as immunogenic and immunomodulatory properties.

Bone and wound healing augmentation with platelet-rich plasma

Over the past two decades, autologous platelets that have been sequestered, concentrated, and mixed with thrombin to generate growth factor-concentrated platelet-rich plasma for application to bone and wounds to aide healing have been a subject of great interest. This article reviews the literature related to the use of autologous platelet-rich plasma in bone and wound healing, and reviews the processes necessary to secure a high concentration of viable platelets. Although not yet definitive, autologous platelet-rich plasma has been shown to be safe, reproducible, and effective in mimicking the natural process of bone and wound healing.

Differential effects of culture-expanded bone marrow cells on the regeneration of bone between the femoral and the tibial lengthenings

BACKGROUND

Transplantation of culture-expanded bone marrow cells (BMC) and platelet-rich plasma (PRP) during limb lengthening shorten the treatment period by accelerating callus formation, but the direct effects of BMC and PRP on the regeneration of the bone have not been determined.

METHODS

Fifty-one bones (23 femora, 28 tibiae) in 28 patients (17 males, 11 females), with an average age of 15.0+/-3.21 years, were lengthened by treatment with BMC and PRP. Clinical outcome was compared between the 51 bones with BMC and PRP treatment and the 60 bones without cell therapy. The parameters including age at surgery, length gained, healing index (HI), number of BMC, bone-specific alkaline phosphatase (BAP) activity of BMC, and PRP concentration, were compared between the femur and the tibia treated with BMC and PRP. Linear regression analysis was then performed to correlate the HI and other variables.

RESULTS

The HI of the BMC and PRP groups was significantly lower than that of the control group. Average HI, amount of lengthening, number of BMC, BAP activity, and PRP concentration were 30.0+/-6.72 days/cm, 8.10+/-2.90 cm, 1.35+/-0.56 x 10(7), 9.02+/-3.98 U/L, and 2.4+/-0.7 x 10(6)/UL, respectively. There were no significant differences in the length gained, the number and BAP activity of BMC, and the PRP concentration between the femur and the tibia. Femoral lengthening showed significantly faster healing than tibial lengthening, although the age at surgery was significantly older in femoral lengthening. A negative relationship between the HI and the length gained was observed in the tibia. In the femur, there was a negative linear relationship between the HI and the number and BAP activity of BMC, whereas no significant correlations were detected in the tibia.

CONCLUSIONS

In femoral lengthening, decrease in the HI was remarkable by BMC and PRP transplantation, and there was a progressive increase in bone healing as the number and the osteoblastic differentiation of transplanted BMC increased. Our results suggested that regionally varying bone-forming processes by cell transplantation might be related to local blood supply and soft tissue covering.

LEVEL OF EVIDENCE

Therapeutic retrospective study, level III.

The biology of platelet-rich plasma and its application in trauma and orthopaedic surgery: a review of the literature

Although mechanical stabilisation has been a hallmark of orthopaedic surgical management, orthobiologics are now playing an increasing role. Platelet-rich plasma (PRP) is a volume of plasma fraction of autologous blood having platelet concentrations above baseline. The platelet alpha granules are rich in growth factors that play an essential role in tissue healing, such as transforming growth factor-beta, vascular endothelial growth factor, and platelet-derived growth factor. PRP is used in various surgical fields to enhance bone and soft-tissue healing by placing supraphysiological concentrations of autologous platelets at the site of tissue damage. The easily obtainable PRP and its possible beneficial outcome hold promise for new regenerative treatment approaches. The aim of this literature review was to describe the bioactivities of PRP, to elucidate the different techniques for PRP preparation, to review animal and human studies, to evaluate the evidence regarding the use of PRP in trauma and orthopaedic surgery, to clarify risks, and to provide guidance for future research.

Treatment of tendon and muscle using platelet-rich plasma

Tendon and muscle injuries are common in elite and weekend athletes. Treatment of these injuries in both groups is rapidly evolving. Sports medicine patients are demanding better and less invasive solutions for all types of musculoskeletal disorders. In this context, platelet-rich plasma (PRP) has emerged as a potential solution. PRP is a fraction of whole blood containing concentrated growth factors and proteins. These cytokines direct tissue healing through autocrine and paracrine effects. The number of basic science, animal, and human investigations of PRP for tendon and muscle injuries worldwide has risen sharply in recent years. These studies are helping clinicians better understand the mechanisms of PRP and are guiding novel treatment protocols. In this paper, the value of PRP as a treatment for acute or chronic tendon and muscle disorders is explored.

The clinical use of platelet-rich plasma in the promotion of bone healing: a systematic review

Platelet-rich plasma has been shown in several in vitro and animal studies to play a role in promoting new bone formation. A systematic literature review was conducted to identify the current relevant evidence base, searching across multiple sources including Medline, Embase and the Cochrane Library, and finding five clinically relevant articles. Only one was a randomised controlled trial, but this was underpowered for the outcome measure defined. Three studies exclusively concerned children, and included those with congenital limb deformities. Two other reports were case series. Early clinical results suggest that the use of platelet-rich plasma is safe and feasible, but that at present there is no clinical evidence of benefit in either acute or delayed fracture healing.

The effect of the platelet concentration in platelet-rich plasma gel on the regeneration of bone

The aim of our study was to investigate the effect of platelet-rich plasma on the proliferation and differentiation of rat bone-marrow cells and to determine an optimal platelet concentration in plasma for osseous tissue engineering. Rat bone-marrow cells embedded in different concentrations of platelet-rich plasma gel were cultured for six days. Their potential for proliferation and osteogenic differentiation was analysed. Using a rat limb-lengthening model, the cultured rat bone-marrow cells with platelet-rich plasma of variable concentrations were transplanted into the distraction gap and the quality of the regenerate bone was evaluated radiologically. Cellular proliferation was enhanced in all the platelet-rich plasma groups in a dose-dependent manner. Although no significant differences in the production and mRNA expression of alkaline phosphatase were detected among these groups, mature bone regenerates were more prevalent in the group with the highest concentration of platelets. Our results indicate that a high platelet concentration in the platelet-rich plasma in combination with osteoblastic cells could accelerate the formation of new bone during limb-lengthening procedures.