A new mouse model of post-traumatic joint injury allows to identify the contribution of Gli1+ mesenchymal progenitors in arthrofibrosis and acquired heterotopic endochondral ossification.

Complex injury and open reconstructive surgeries of the knee often lead to joint dysfunction that may alter the normal biomechanics of the joint. Two major complications that often arise are excessive deposition of fibrotic tissue and acquired heterotopic endochondral ossification. Knee arthrofibrosis is a fibrotic joint disorder where aberrant buildup of scar tissue and adhesions develop around the joint.

Regional gene therapy for bone healing using a 3D printed scaffold in a rat femoral defect model.

At the present time there are no consistently satisfactory treatment options for some challenging bone loss scenarios. We have previously reported on the properties of a novel 3D-printed hydroxyapatite-composite material in a pilot study, which demonstrated osteoconductive properties but was not tested in a rigorous, clinically relevant model. We therefore utilized a rat critical-sized femoral defect model with a scaffold designed to match the dimensions of the bone defect.

Regional Gene Therapy with Transduced Human Cells: The Influence of "Cell Dose" on Bone Repair.

Regional gene therapy using a lentiviral vector containing the complementary DNA (cDNA) has been shown to heal critical-sized bone defects in rodent models. An appropriate "cellular dose" needs to be defined for eventual translation into human trials. The purpose of this study was to evaluate bone defect healing potential and quality using three different doses of transduced human bone marrow cells (HBMCs).

Ex vivo gene therapy using human bone marrow cells overexpressing BMP-2: "Next-day" gene therapy versus standard "two-step" approach.

Traditionally, ex vivo gene therapy involves a two-step approach, with culture expansion of cells prior to transduction and implantation. We have tried to simplify this strategy and eliminate the time and cost associated with culture expansion, by introducing "next-day" regional gene therapy using human bone marrow cells. The purpose of this study was to determine whether a lentiviral vector (LV) carrying the cDNA for BMP-2 can transduce freshly isolated human BM cells, leading to abundant BMP production and bone formation in vivo, and evaluate the in vivo osteoinductive potential of "next-day" gene therapy and the standard "two-step" tissue culture expansion approach.

Comparative musculoskeletal anatomy of chameleon limbs, with implications for the evolution of arboreal locomotion in lizards and for teratology.

Chameleon species have recently been adopted as models for evo-devo and macroevolutionary processes. However, most anatomical and developmental studies of chameleons focus on the skeleton, and information about their soft tissues is scarce. Here, we provide a detailed morphological description based on contrast enhanced micro-CT scans and dissections of the adult phenotype of all the forelimb and hindlimb muscles of the Veiled Chameleon (Chamaeleo calyptratus) and compare these muscles with those of other chameleons and lizards.