Efficacy of a collagen-based dressing in an animal model of delayed wound healing.

OBJECTIVE: The aim of this study was to evaluate in vitro and in vivo the efficacy of GBT013, a collagen-based dressing, for the treatment of chronic wounds, in a db/db mouse model of diabetes. METHOD: Macroscopic and histologic analyses of db/db mice wound healing with GBT013 or saline gauze were assessed. The mRNA expression and the proliferation of dermal fibroblast were investigated. Matrix metalloproteinases (MMP)-2 and MMP-9 activities were quantified. RESULTS: In db/db mice, GBT013 improves wound epithelialisation when compared with saline gauze. Histological analysis of scar tissue also shows an enhancement of remodelling associated with no sign of acute inflammation. In addition, GBT013 significantly decreases interleukin (IL)-6 and IL-8, significantly increases tissue inhibitors of metalloproteinases (TIMP)-1 and TIMP-2 fibroblast mRNA expression and significantly reduces in vitro MMP-2 and MMP-9 enzymatic activities. Moreover, GBT013 allows cell growth inside the matrix and stimulates proliferation of human dermal fibroblast. CONCLUSION: By contributing to restore MMPs/TIMPs balance, GBT013 may function in all key stages of wound healing, such as inflammation, proliferation and tissue remodelling, and ultimately may provide a favourable environment for skin repair. DECLARATION OF INTEREST: This work was supported by Genbiotech, the R&D subsidiary of Laboratoires Genévrier, a pharmaceutical company.

Increased pregnancy rate using standardized coculture on autologous endometrial cells and single blastocyst transfer : a multicentre randomized controlled trial.

Despite excellent published results, the lack of well-designed, multicentre, randomized clinical trials results in an absence of general consensus on the efficacy of autologous endometrial cells coculture (AECC) in Assisted Reproductive Technology (ART). An open, multicentre, prospective, randomized controlled trial was designed to compare the pregnancy rate (PR) after the transfer of one blastocyst on day 5 after AECC to the transfer of one embryo on day 3 (control group). Patients were women aged 18 to 36, undergoing an ART cycle with no more than 1 embryo transfer failure. Sample size was calculated at 720 for a superiority trial involving an intermediate analysis at 300 patients. We present the results of the intermediate analysis that resulted in the study ending considering the observed difference. Three hundred thirty nine patients were randomized: 170 in the AECC group and 169 in the control group. The clinical PR per transfer was 53.4% with AECC and 37.3% in the control group (p=0.025). The quality of embryos was improved with AECC. These results suggest that implementation of the AECC technique to a large number of In-Vitro Fertilization (IVF) centres could lead to a substantial improvement in the proportion of successful assisted reproduction. The study was supported by the Laboratoires Genévrier, France.

scAAV-mediated gene transfer of interleukin-1-receptor antagonist to synovium and articular cartilage in large mammalian joints.

With the long-term goal of developing a gene-based treatment for osteoarthritis (OA), we performed studies to evaluate the equine joint as a model for adeno-associated virus (AAV)-mediated gene transfer to large, weight-bearing human joints. A self-complementary AAV2 vector containing the coding regions for human interleukin-1-receptor antagonist (hIL-1Ra) or green fluorescent protein was packaged in AAV capsid serotypes 1, 2, 5, 8 and 9. Following infection of human and equine synovial fibroblasts in culture, we found that both were only receptive to transduction with AAV1, 2 and 5. For these serotypes, however, transgene expression from the equine cells was consistently at least 10-fold higher. Analyses of AAV surface receptor molecules and intracellular trafficking of vector genomes implicate enhanced viral uptake by the equine cells. Following delivery of 1 × 10(11) vector genomes of serotypes 2, 5 and 8 into the forelimb joints of the horse, all three enabled hIL-1Ra expression at biologically relevant levels and effectively transduced the same cell types, primarily synovial fibroblasts and, to a lesser degree, chondrocytes in articular cartilage. These results provide optimism that AAV vectors can be effectively adapted for gene delivery to large human joints affected by OA.

A simple, lanthanide-based method to enhance the transduction efficiency of adenovirus vectors.

Based upon the powerful bridging and charge-masking properties of lanthanide cations (Ln3+), we have investigated their use to improve the transduction efficiency of adenovirus vectors. Using a luciferase marker gene, it was possible to increase transgene expression by the murine mesenchymal stem cell line C3H10T(1/2) by up to four log orders when using very low multiplicities of infection in conjunction with Ln3+; La3+ was superior to Gd3+, Y3+ and Lu3+ in this regard. All Ln3+ were more effective than Ca2+. Flow cytometry, using a green fluorescent protein marker gene, confirmed that La3+ increased both the percentage of transduced cells and the level of transgene expression per cell. Transduction of primary cultures of a variety of different mesenchymal cells from human, rabbit, bovine and rat sources, as well as gene transfer to synovium and muscle in vivo, was also greatly enhanced. Our findings suggest that this lanthanide-based method holds much promise for expediting both experimental and clinical applications of gene transfer with adenoviral vectors.

cDNA sequencing and expression analysis of Dicentrarchus labrax heme oxygenase-1.

The liver cDNA encoding heme oxygenase--1 (HO-1) was sequenced from European sea bass (Dicentrarchus labrax) (accession number no. EF139130). The HO-1 cDNA was 1250 bp in nucleotide length and the open reading frame encoded 277 amino acid residues. The deduced amino acid sequence of the European sea bass had 75% and 50% identity with the amino acid sequences of tetraodontiformes (Tetraodon nigroviridis and Takifugu rubripes) and human HO-1 proteins, respectively. A short hydrophobic transmembrane domain at the C--terminal region was found, and four histidine residues were highly conserved, including human his25 that is essential for HO catalytic activity. RT-PCR of mRNA from eight different European sea bass tissues revealed that, in a homeostatis state, the heme oxygenase--1 was abundant in the spleen and liver but not in the brain.

Gene therapeutic approaches-transfer in vivo.

Osteoarthritis (OA) is common, debilitating, expensive, incurable and very difficult to treat. Gene transfer to the synovial linings of affected joints is a promising strategy for achieving sustained, therapeutic, intraarticular concentrations of anti-arthritic gene products. This is not reasonably possible with existing, alternative technologies. The present review summarizes progress in achieving direct, in vivo intraarticular gene delivery and expression. Numerous non-viral vectors have been evaluated for their ability to transfect the synovia of experimental animals following intraarticular injection. None have given more than low levels of temporary transgene expression and many are inflammatory. Several viral vectors, however, are very effective in this regard and successfully treat experimental models of OA. Adeno-associated virus has been used in a phase I study for the gene therapy of rheumatoid arthritis. Its use in a clinical trial for treating OA is pending.

Adenovirus-mediated gene transfer of glutamine: fructose-6-phosphate amidotransferase antagonizes the effects of interleukin-1beta on rat chondrocytes.

OBJECTIVE: To determine whether overexpression of glutamine: fructose-6-phosphate amidotransferase (GFAT) in synoviocytes will antagonize the response to interleukin-1beta (IL-1beta) of chondrocytes and synovial fibroblasts in co-culture. METHODS: Synovial fibroblasts from the rat were transduced by an adenovirus carrying the cDNA for GFAT and then co-cultured with rat chondrocytes encapsulated in alginate beads. Following challenge with 1, 5, or 10 ng/ml of IL-1beta for 24 h, proteoglycan synthesis by the chondrocytes was determined by incorporation of Na2(35)SO4. Production of nitric oxide (NO) and prostaglandin E2 (PGE2) were monitored by assay of conditioned medium from the co-culture. RESULTS: IL-1beta treatment of untransduced-synoviocyte/chondrocyte co-cultures resulted in markedly decreased proteoglycan synthesis by the chondrocytes, and increased NO and PGE2 levels in the culture medium. In contrast, adenovirus-mediated transfer of GFAT in synoviocytes prevented both the decrease in chondrocyte proteoglycan synthesis and increases in NO and PGE2 provoked by IL-1beta. CONCLUSIONS: Our study suggests that in a synoviocyte/chondrocyte co-culture system, overexpression of GFAT by synoviocytes significantly inhibits subsequent stimulation by IL-1beta in vitro. Since GFAT is the rate limiting enzyme in the synthesis of intracellular glucosamine and its derivatives, these results may open new possibilities for osteoarthritis treatment.

Osteoarthritis gene therapy.

Osteoarthritis (OA) is the Western world's leading cause of disability. It is incurable, costly and responds poorly to treatment. This review discusses strategies for treating OA by gene therapy. As OA affects a limited number of weight-bearing joints and has no major extra-articular manifestations, it is well suited to local, intra-articular gene therapy. Possible intra-articular sites of gene transfer include the synovium and the cartilage. Most experimental progress has been made with gene transfer to synovium, a tissue amenable to genetic modification by a variety of vectors, using both in vivo and ex vivo protocols. The focus so far has been upon the transfer of genes whose products enhance synthesis of the cartilaginous matrix, or inhibit its breakdown, although there is certainly room for alternative targets. It is possible to build a convincing case implicating interleukin-1 (IL-1) as a key mediator of cartilage loss in OA, and the therapeutic effects of IL-1 receptor anatagonist (IL-1Ra) gene transfer have been confirmed in three different experimental models of OA. As transfer of IL-1Ra cDNA to human arthritic joints has already been accomplished safely, we argue that clinical studies of intra-articular IL-1Ra gene transfer in OA are indicated and should be funded. Of the available vector systems, recombinant adeno-associated virus may provide the best combination of safety with in vivo delivery using current technology.

Gene delivery to cartilage defects using coagulated bone marrow aspirate.

The long-term goal of the present study is to develop a clinically applicable approach to enhance natural repair mechanisms within cartilage lesions by targeting bone marrow-derived cells for genetic modification. To determine if bone marrow-derived cells infiltrating osteochondral defects could be transduced in situ, we implanted collagen-glycosaminoglycan (CG) matrices preloaded with adenoviral vectors containing various marker genes into lesions surgically generated in rabbit femoral condyles. Analysis of the recovered implants showed transgenic expression up to 21 days; however, a considerable portion was found in the synovial lining, indicating leakage of the vector and/or transduced cells from the matrix. As an alternative medium for gene delivery, we investigated the feasibility of using coagulated bone marrow aspirates. Mixture of an adenoviral suspension with the fluid phase of freshly aspirated bone marrow resulted in uniform dispersion of the vector throughout, and levels of transgenic expression in direct proportion to the density of nucleated cells in the ensuing clot. Furthermore, cultures of mesenchymal progenitor cells, previously transduced ex vivo with recombinant adenovirus, were readily incorporated into the coagulate when mixed with fresh aspirate. These vector-seeded and cell-seeded bone marrow clots were found to maintain their structural integrity following extensive culture and maintained transgenic expression in this manner for several weeks. When used in place of the CG matrix as a gene delivery vehicle in vivo, genetically modified bone marrow clots were able to generate similarly high levels of transgenic expression in osteochondral defects with better containment of the vector within the defect. Our results suggest that coagulates formed from aspirated bone marrow may be useful as a means of gene delivery to cartilage and perhaps other musculoskeletal tissues. Cells within the fluid can be readily modified with an adenoviral vector, and the matrix formed from the clot is completely natural, native to the host and is the fundamental platform on which healing and repair of mesenchymal tissues is based.