[Low level laser therapy : A narrative literature review on the efficacy in the treatment of rheumatic orthopaedic conditions]. / Low-Level-Lasertherapie : Eine narrative Literaturübersicht zur Wirksamkeit bei der Behandlung rheumatologisch-orthopädischer Krankheitsbilder.

BACKGROUND: In low level laser therapy (LLLT) low wattage lasers are used to irradiate the affected skin areas, joints, nerves, muscles and tendons without any sensation or thermal damage. Although the exact mechanism of its effect is still unknown, it seems beyond dispute that LLLT induces a variety of stimulating processes at the cellular level affecting cell repair mechanisms, the vascular system and lymphatic system. LLLT has been popular among orthopaedic practitioners for many years, whereas university medicine has remained rather sceptical about it. OBJECTIVES: Overview of studies on the efficacy of LLLT in the treatment of rheumatic orthopaedic conditions, i. e. muscle, tendon lesions and arthropathies. MATERIALS AND METHODS: Narrative literature review (PubMed, Web of Science). RESULTS: While earlier studies often failed to demonstrate the efficacy of LLLT, several recent studies of increasing quality proved the efficacy of LLLT in the treatment of multiple musculoskeletal pain syndromes like neck or lower back pain, tendinopathies (especially of the Achilles tendon) and epicondylolpathies, chronic inflammatory joint disorders like rheumatoid arthritis or chronic degenerative osteoarthritis of the large and small joints. In addition, there is recent evidence that LLLT can have a preventive capacity and can enhance muscle strength and accelerate muscle regeneration. CONCLUSION: LLLT shows potential as an effective, noninvasive, safe and cost-efficient means to treat and prevent a variety of acute and chronic musculoskeletal conditions. Further randomized controlled studies, however, are required to confirm this positive assessment.

Good short- to medium-term results after osteochondral autograft transplantation (OAT) in middle-aged patients with focal, non-traumatic osteochondral lesions of the knee.

BACKGROUND: Osteochondral autograft transplantation (OAT) offers the opportunity to repair cartilaginous defects by restoring hyaline cartilage anatomy. Encouraging results have been reported in patients suffering from acute knee trauma or osteochondritis dissecans. Patients with focal chronic, non-traumatic osteochondral (FCNO) lesions of the knee, however, have rarely been the subject of investigation. Some authors even consider higher age as contraindications to OAT. OBJECTIVES: To assess the short- to medium-term outcomes of OAT in middle-aged patients with FCNO lesions of the knee and to identify predictors of clinical outcome. HYPOTHESIS: Filling FCNO defects with autologous osteochondral grafts should restore the congruency of the middle-aged knee joint and thereby reduce pain and loss of function on the one hand, and increase quality of life on the other hand. METHODS: One hundred and twelve patients (48.01±1.12yrs) with FCNO of the knee were assessed before OAT and 26.2±0.24 months after surgery. Clinical outcome was measured by WOMAC Index and the Visual Analogue Scale (VAS) for pain. RESULTS: Pain (pre-OAT VAS vs. post-OAT VAS: 7.14±0.19 vs. 3.74±0.26, P<0.001) was reduced and quality of life (pre-OAT WOMAC vs. post-OAT WOMAC: 134.88±5.84 vs. 65.92±5.34, P<0.001) improved. Retropatellar defects were associated with poor outcome, while overall surface and number of cylinders were not. DISCUSSION: Middle-aged patients with FCNO of the knee also profit from OAT at a short follow-up. LEVEL OF EVIDENCE: IV. Mono-centric, prospective clinical series.

[MALDI mass spectrometry of the meniscus. Objectification of morphological findings]. / MALDI-Massenspektrometrie am Meniskus. Objektivierung morphologischer Befunde.

BACKGROUND: The classification of meniscal lesions requires correlation with clinical data. For the standardization of histopathology reports a discrimination between normal, low-grade lesions and high-grade lesions is feasible. This classification can be further specified using other methods. MATERIAL AND METHODS: Formalin-fixed, paraffin-embedded specimens of meniscal tissue from 68 patients were analyzed by matrix-assisted laser desorption ionization (MALDI) imaging. RESULTS: The classification of meniscal lesions and differentiation between low-grade and high-grade and acute versus non-acute degeneration is possible by determination of the differential expression of mass-to-charge ratios by statistical comparisons using the P-value from combined Wilcoxon and Kruskal-Wallis (PWKW) tests and a predefined average two-fold difference in intensity. CONCLUSION: The concept of a "meniscus report" is introduced for documentation of meniscus tissue specimens integrating histological, histochemical and proteomic data, thereby specifying the degree of degeneration and the assessment of acute or non-acute lesions. Mass spectrometry contributes to an objective histopathology report. An advisory opinion should always be based on close correlation of clinical and morphological evaluations.

[Sonographic standard values for the patellar tendon in competitive athletes]. / Sonografische Dimensionen der Patellasehne von Hochleistungssportlern.

BACKGROUND: The sonographic validity of a thickened tendon as a morphological correlate of patellar tendinopathy is beyond dispute, regarding the proximal insertion at the very least. There is, however, a lack of mandatory standard values for competitive athletes and normal individuals. In addition, research findings concerning the clinical relevance of qualitative changes such as hypoechogenic regions are still inconclusive. PARTICIPANTS: 202 national squad athletes from the German track and field federation and 199 age-matched normal individuals were examined sonographically. METHOD: 404 patellar tendons of athletes were compared as to tendon diameter at the (i) proximal insertion, (ii) waist, and (iii) distal insertion with 398 patellar tendons of normal individuals using the portable ultrasound scanner "Just Vision". Furthermore, qualitative pathologies and clinical symptoms were assessed. RESULTS: Athletes reported more clinical symptoms and their tendons were thicker than normal tendons at all three positions (all p's < 0.01). In athletes, proximal diameters above 6.0 mm were very likely to go along with clinical symptoms. There was an association between tendon diameter and symptoms at all three positions among the athletes, whereas in controls, this was only true for the proximal insertion. Only few consistent qualitative differences were found between athletes and normal individuals. CONCLUSION: The pattern of results confirms the clinical relevance of the proximal tendon diameter for patellar tendinopathy and provides standard values which should be evaluated in future research with regard to their prognostic utility in competitive sports. The importance of qualitative pathologies such as hypoechogenic regions could not be firmly asserted.

[Training adaptation of the Achilles tendon in competitive athletes--sonographic standard values for the Achilles tendon]. / Trainingsadaptation der Achillessehne beim Hochleistungssportler--sonografische Grenzwerte für Achillessehnen.

BACKGROUND: Current theories and empirical results regarding the sonographic dimensions of the Achilles tendon as well as an alleged training adaptation of the tendon in competitive athletes are tested for the first time in a large in vivo sample. The pathological validity of a thickened tendon in competitive athletes is under scrutiny. MATERIAL AND METHOD: In addition to 202 national squad athletes from the German track and field federation, 199 age-matched normal individuals were examined sonographically. The portable ultrasound scanner Just Vision was used to compare 404 Achilles tendons of athletes with 398 Achilles tendons of normal individuals as to tendon diameter. Furthermore, pathologies were assessed. RESULTS: Achilles tendon diameter at the calcanear insertion was 4.2 ± 0.72 mm on average. Athletes' tendons were thicker than normal tendons (p < 0.001) - athletes, however, also reported more clinical symptoms (p < 0.001). In athletes, increasing diameters were associated with more clinical problems as opposed to normal individuals. At the tendon waist, diameters above 6.0 mm were very likely to go along with pathologies. CONCLUSIONS: For the first time, valid data of Achilles tendon diameters in competitive athletes and normal individuals have been presented. The emerging pattern of results clearly contradicts the notion of a physiological training adaptation of the Achilles tendon.

Autologous conditioned serum (Orthokine) is an effective treatment for knee osteoarthritis.

OBJECTIVE: Osteoarthritis (OA) is prevalent and difficult to treat. Autologous conditioned serum (ACS), marketed under the trade name Orthokine, is a novel, injectable antiarthritic derived from the patient's own blood. The present study is the first time ACS has undergone a controlled clinical trial. METHOD: We investigated 376 patients with knee OA in a prospective, randomized, patient- and observer-blinded, placebo-controlled trial using an intention-to-treat analysis (ITT). The clinical effects of ACS were compared to hyaluronan (HA) and saline (placebo) as assessed by patient-administered outcome instruments (Western Ontario and McMaster Universities osteoarthritis index, global patient assessment, visual analog scale, Short-Form 8) after 7, 13 and 26 weeks. After 104 weeks an observer-blinded follow-up was carried out. Frequency and severity of adverse events were used as safety parameters. RESULTS: In all treatment groups, intra-articular injections produced a reduction in symptoms as well as an improvement in quality of life. However, the effects of ACS were significantly superior to those of HA and saline for all outcome measures and time points, and improvements were clinically relevant; there were no differences between the effects of HA and saline. The frequency of adverse events was comparable in the ACS and saline groups, but higher in the HA group. CONCLUSION: The data demonstrate that ACS injection considerably improves clinical signs and symptoms of OA. It remains to be determined whether ACS is disease-modifying, chondroprotective, or chondroregenerative.

All-ceramic single-tooth restorations: choosing the material to match the preparation--preparing the tooth to match the material.

The shape of a crown preparation is the prime determinant for the choice of material for an all-ceramic restoration. One essential factor is the available space for the restoration, which requires a certain occlusal thickness. The dentist's preparation design determines the available vertical clearance, and the dental technician has the responsibility of advising the dentist with regard to either choosing the right material to match the preparation or to preparing the tooth to match the material. Assuming a minimum static fracture strength of > 2000 N, the following materials can be used for all-ceramic crowns: Laboratory surveys have shown that in most situations, the available occlusal clearance in clinical reality is only 0.8 to 0.9 mm (after cementing). This shows that the available space will often be insufficient for providing monoblock crowns and still on the tight side for veneered oxide ceramics (In Ceram, zirconia, etc.). However, crowns made of veneered oxide ceramics are much more complex to fabricate and much more expensive. By simply providing a minimal occlusal thickness of 1.5 mm, the treatment provider could therefore easily facilitate the use of the much more economical monoblock crowns without compromising either esthetics or strength. Actually, crowns with veneered oxide ceramic copings do not offer any higher fracture resistance compared to Mark II crowns as long as the minimum thickness requirements are met. The flexural strength of CAD/CAM-fabricated lithium disilicate rods is about twice that of CAD/CAM-fabricated Mark II rods. When used for crowns with a wall thickness of 1.5 mm, however, both materials exhibit the same fracture strength of between 2000 and 2500 N. This is related to the different reinforcing action of the adhesive luting agent, which is essentially required for both these materials. When choosing a material, preparation shapes, technical complexity and cost should be thoroughly compared and scrutinized and should figure prominently in the discussions between dentists and dental technician. Unfavorable preparation shapes for single crowns will necessitate compromises in terms of the choice of materials that result in high cost but do not offer anything in the way of higher fracture resistance. What constitutes an appropriate all-ceramic restoration for a single tooth? Do all-ceramic single crowns require the same material bulk as multi-unit bridges? Everything would indicate that a suitable preparation geometry allows feldspathic ceramic monoblock crowns to be milled that do not require any extensive finishing efforts such as thermal annealing or in-laboratory veneering while at the same time demanding no compromises in terms of esthetics and load-bearing capacity.

VITA CAD-Temp for inLab and Cerec 3D.

VITA CAD-Temp is a composite block which enables high-quality provisional restorations to be created using the Sirona milling units. The new Cerec MC XL and inLab MC XL units are the preferred choice on account of their significantly higher milling speeds. The technical requirements are described and an illustrated practical example presented. CAD-Temp constitutes a good example of rapid and efficient collaboration between dentists and dental technicians. This is illustrated on the basis of an example relating to the field of implant prosthetics.

Direct adenoviral transfer of bone morphogenetic protein-2 cDNA enhances fracture healing in osteoporotic sheep.

Osteoporosis, a major public health burden, is associated with increased fracture risk. Fracture healing in osteoporosis is delayed, with reduced callus formation and impaired biomechanical properties of newly formed bone leading to high risk of fixation failure. Adenoviral gene transfer of bone morphogenetic protein-2 (BMP-2) has been shown to enhance fracture healing. This study evaluated the ability of gene transfer to enhance bone healing in osteoporosis. An established sheep model of osteoporosis with well-characterized alterations in fracture healing was used. Osteotomies were created surgically in the tibias of adult female sheep and monitored for 8 weeks, using radiographic, biomechanical, and histological methods. For pilot experiments, primary ovine osteoblasts and mesenchymal stem cells were transduced with a recombinant adenovirus carrying BMP-2 cDNA (Ad.BMP-2). Large increases in alkaline phosphatase production and mineralization confirmed the ability of human BMP-2 to stimulate osteoblastic differentiation in sheep. In vivo bending stiffness measurements during fracture healing as well as ex vivo torsional stiffness measurements demonstrated stiffer callus tissue after treatment with Ad.BMP-2. The differences were found mainly in the early fracture-healing period. Computed tomography demonstrated that animals receiving the BMP-2 cDNA had larger cross-sectional callus area and higher callus density. Histological examination of the tibias confirmed enhanced callus formation. Direct, local adenoviral delivery of an osteogenic gene thus led to enhanced healing of fractures in an ovine model of osteoporosis. These promising data encourage the further development of genetic approaches to enhance bone healing in patients suffering osteoporosis-associated fractures.

Effect of BMP-2 gene transfer on bone healing in sheep.

Critical size defects of bone and delayed fracture healing due to metabolic disorders are still problems in orthopaedic surgery. Adenoviral vectors encoding bone morphogenetic protein-2 (Ad.BMP-2) have been used to stimulate bone formation in small animals. The present study evaluated the use of direct adenoviral gene transfer for inducing bone formation in a large animal. Standardized iliac crest defects were created surgically on both sides of the pelvic bone of white mountain sheep. The efficiency of gene transfer was evaluated using recombinant adenoviruses carrying the cDNA for luciferase. High levels of transgene expression, restricted to the site of injection, were found for the 1st week. Transgene expression then fell considerably, but could still be detected for up to 5 weeks. To investigate the effect on bone healing, Ad.BMP-2 (10(11) particles in 200 mul saline) was unilaterally injected into iliac crest defects and into tibial osteotomies. The contralateral defects remained untreated to evaluate possible systemic effects. The controls were treated with saline solution. Bone formation within the defect, assessed by micro-computed tomography (CT) measurement at 8 weeks, and callus formation after osteotomy were significantly reduced following direct application of Ad.BMP-2. The retardation compared to untreated control animals was additionally found at the contralateral iliac crest indicating a systemic inhibitory effect. Histological analysis confirmed the CT measurement and showed an increased number of inflammatory cells within both defects. Antibodies against the adenovirus and the transgene product were detected in all treated animals. These data show a systemic retardation of bone formation following a single local injection of Ad.BMP-2 in sheep. This finding stands in contrast to the data obtained from small animal models. Further studies are needed to determine the contribution of the immune response to these results, and whether a lower dose of Ad.BMP-2 would be advantageous.

Shading of ceramic crowns using digital tooth shade matching devices.

In the 1990s, there was great optimism due to the development of devices for measuring tooth shade. The frequently not so simple, visual determination of the shade of a tooth was to be done with the aid of a device which recognizes the shade and describes it accurately by reference to a color chart. However, the skepticism towards such devices was also great. It is known that the color effect frequently differs strongly when comparing a tooth from the shade guide with a metal ceramic crown, despite identical shade designation. Anyone who considers visual shade determination to be inadequate and places his hopes in digital shade matching devices will be disappointed. It is the shade-generating structures of the metal ceramic and frequently of the veneer layers that turn out to be too thin which, despite correct shade selection, cause a different color perception. Such problems have been reduced decisively with the development of fracture-proof hard porcelain caps (Vita In-Ceram) with optical characteristics similar to teeth. In addition, the Vita System 3D-Master tooth shade system developed in 1998 by Vita in cooperation with Dr. Hall from Australia, leads the practitioner to a better understanding of the primary tooth shade characteristics of "brightness (value)", "color intensity (chroma)" and "color (wave length of the visible light, hue)". These two innovations allow a more accurate estimate of the basic shade of a natural tooth (reference tooth) and the imitation in the laboratory of its natural, shade-generating structures. If digital shade measurement supplements the visual shade estimate, then a further improvement can be expected--especially in the recognition of the basic shade. Qualitative descriptions of subjective shade measurement of a natural tooth and of its imitation in the dental laboratory by ceramics can be found frequently in professional journals and publications. With digital tooth shade matching devices, which apart from the color code of the color chart also reproduce exact, colorimetric values, such work processes can be recorded quantitatively and objectively. Reports about this type of controlled shade determination and generation are found rarely in the literature, which is surprising in view of the large number of tooth shade matching devices and dental ceramic systems available. In the present paper, the influence of the individual ceramic layers on color perception is measured and described under standardized conditions. The creation of the basic shade as it results from the composition of the various ceramic layers is traced with a spectrophotometer. The Vita In-Ceram Alumina infiltration ceramic and the VitaVM7 veneer ceramic were selected as the ceramic system. MHT-SpectroShade and Vita Easyshade were used as shade matching devices.

The potential of gene therapy for fracture healing in osteoporosis.

Osteoporosis-associated fractures impair a patient's function and quality of life and represent one of the major public health burdens. Demographic changes predict a dramatic increase in osteoporotic fractures. Experimental data have shown that osteoporosis impairs fracture healing. Clinical observations demonstrate high failure rates of implant fixation in osteoporosis. The reduced healing capacity, including impaired bone formation, in osteoporotic humans might be due to defects in mesenchymal stem cells that lead to reduced proliferation and osteoblastic differentiation. Growth factors show remarkable promise as agents that can improve the healing of bone or increase the proliferation and differentiation capacities of mesenchymal stem cells. Their clinical utility is limited by delivery problems. The attraction of gene-transfer approaches is the unique ability to deliver authentically processed gene products to precise anatomical locations at therapeutic levels for sustained periods of time. Unlike the treatment of chronic diseases, it is neither necessary nor desirable for transgene expression to persist beyond the few weeks or months needed to achieve healing. This review presents different approaches of gene therapy to enhance fracture healing and summarizes the promising results of preclinical studies. It focuses on applications of this new technique to fracture healing in osteoporosis. In our opinion, these applications represent some of the few examples in which gene therapy has a good chance of early clinical success.

Apoptotic cell death in the lactating mammary gland is enhanced by a folding variant of alpha-lactalbumin.

Apoptosis is essential to eliminate secretory epithelial cells during the involution of the mammary gland. The environmental regulation of this process is however, poorly understood. This study tested the effect of HAMLET (human alpha-lactalbumin made lethal to tumor cells) on mammary cells. Plastic pellets containing HAMLET were implanted into the fourth inguinal mammary gland of lactating mice for 3 days. Exposure of mammary tissue to HAMLET resulted in morphological changes typical for apoptosis and in a stimulation of caspase-3 activity in alveolar epithelial cells near the HAMLET pellets but not more distant to the pellet or in contralateral glands. The effect was specific for HAMLET and no effects were observed when mammary glands were exposed to native a-lactalbumin or fatty acid alone. HAMLET also induced cell death in vitro in a mouse mammary epithelial cell line. The results suggest that HAMLET can mediate apoptotic cell death in mammary gland tissue.

Regional gene therapy to enhance bone repair.

Gene therapy presents a novel approach to the treatment of challenging bone loss problems. Recombinant, osteogenic growth factors are now available to enhance bone repair, particularly in those applications related to the treatment of fracture nonunions and the enhancement of fusion of the spine. However, there is concern that a single dose of an exogenous protein will not induce an adequate osteogenic signal in many patients, particularly in those cases where there is compromise of host bone and the surrounding soft tissue. Transfer of genes encoding osteogenic proteins has the potential to overcome the delivery problems associated with the use of the proteins themselves. Bone healing is an attractive application for gene therapy, because long-term protein production is not necessary for many bone repair problems. Therefore, the development of gene therapy strategies to treat bone repair problems promises to be easier than the application of gene therapy to treat chronic diseases. The purpose of this review is to highlight the advantages, disadvantages and clinical potential of various gene therapy strategies to enhance bone repair.

[Experiences after 150 cartilage-bone-transplantations of the knee: a prospective analysis of the results]. / Erfahrungen nach 150 Knorpel-Knochen-Transplantationen (KKT) am Kniegelenk: Eine prospektive Ergebnisanalyse.

INTRODUCTION: To evaluate the clinical outcome of cartilage-bone-transplantations of the knee in patients with different indications, we studied the clinical results of 45 patients with a follow-up of 24 months after operation. PATIENTS AND METHODS: 29 male and 16 female patients with a mean age of 37.7 yrs (16-58 yrs) were included. Indications for operation were osteochondritis dissecans (OD) (n=13), limited arthritis (n=20), traumatic lesions (n=5) and retropatellar lesions (n=7). The results were evaluated by clinical score (McDermott Score; preoperatively, and 3, 6, 12, 24 months postoperatively), magnetic resonance imaging, and re-arthroscopy for most patients. RESULTS: 42 of 45 patients judged the operation as successful. The mean score value of all patients raised from 66.3 pts (out of 100 pts) preoperatively to 92.7 pts 24 months postoperatively. The results of the patients with circumscript arthritic lesions (62.9 pts. preoperatively vs. 91.5 pts. postoperatively) were comparable to those of the other patients. CONCLUSION: We conclude that cartilage-bone-transplantation of the knee is a valuable procedure to improve joint function not only after OD or trauma, but also in joints with local arthritic lesions on condition that there is an adequate quality of the donor site.

Mouse mammary gland involution is associated with cytochrome c release and caspase activation.

At weaning, milk producing mammary epithelial cells undergo apoptosis and are removed by phagocytosis. Here, we show that mouse mammary gland involution is associated with mitochondrial cytochrome c release and processing of numerous caspases, including caspase-1, -3, -7, -8 and -9. Induction of caspase-3-like activity paralleled cleavage of poly-(ADP--ribose) polymerase. Dexamethasone inhibited processing of caspase-3, -7 and -8 and apoptosis, but had no effect on caspase-1 accumulation and cytochrome c release. In Bcl-2 transgenic animals, cytochrome c release, caspase activation and apoptosis were impaired. Thus, the pro-apoptotic signaling pathway in mammary epithelial cells during involution involves the release of cytochrome c and activation of caspases. It is inhibited by Bcl-2 at the mitochondrial level and by dexamethasone at a post-mitochondrial level.

[Experimental validation of DXA and MRI-based bone density measurement by ash-method]. / Experimentelle Validierung einer DXA- und MRT-basierten Knochendichtemessung durch Veraschung.

Different methods have been established for bone density measurements such as dual energy X-ray absorptiometry (DXA), quantitative computertomography (QCT), and scintigraphy (VQ-Scan). There are hints that magnetic resonance imaging (MRI) might become a new option for the evaluation of bone density. The aim of this study was to investigate correlations between MRI vs. DXA and MRI vs. mineral content of lumbar vertebrae. Data were obtained from ten lumbar vertebral bodies of cattles. The T-1 MRI-sequences SE, PS, and the T-2 Sequence STIR were used for analysis. Total pixel numbers and a pixel per area ratio were determined. Values were compared to DXA-measurements, to the wet weight, and to separated measurements of the spongious, trabecular, and total mineral content of the vertebral body after ashing. We found correlations between DXA (g/vertebral body) vs. mineral content by ash-method (0.918; p < 0.01), DXA vs. MRI (SE-sequence) (-0.872; p < 0.01), and MRI (SE-sequence) vs. mineral content (0.775; p < 0.01). No correlations were found between PS- or STIR-sequences and the ash-method. This study shows that the determination of the bone mineral content of vertebrae is possible applying MRI in the T1-weighted SE-sequence. Without radiation, the MRI provides additionally early detection of trabecular lesions, fractures, and deformities at the spine, without other diagnostic procedures becoming necessary.

[Osteochondral shear fractures in children. A case report and critical review of the literature]. / Osteochondrale Abscherfrakturen bei Kindern. Eine Falldarstellung unter kritischer Wertung der Literatur.

Only few articles on osteochondral flake fractures in children have been published. Diagnostic tools have been improved over the past decades, but still, diagnosis of severe osteochondral defects may be delayed. The presented case report describes the different techniques currently being available for the diagnosis of osteochondral flake fractures. The different therapeutic options for the treatment of osteochondral flake fractures in children are discussed based on the current literature. This article demonstrates the necessity to consider severe injuries, even if impressive clinical symptoms are lacking.

Gene therapy for osteoporosis: evaluation in a murine ovariectomy model.

Various cytokines and cytokine antagonists hold promise as new therapeutic agents for osteoporosis, but their application is hindered by delivery problems. Gene transfer offers an attractive technology with which to obviate these restrictions. Its utility was evaluated in an animal model of osteoporosis. Disease was induced by surgical ovariectomy and monitored by measuring bone weight after 12 days, and by histomorphometry after 5 weeks. Genes were transferred to the mice by intramedullary injection of adenoviral vectors. LacZ and luciferase marker genes were used to identify the bone marrow cells transduced by this procedure, and to track the possible spread of transgenes to other organs. The effect on bone loss of transferring a cDNA encoding the human interleukin-1 receptor antagonist (IL-1Ra) was then evaluated. The intramedullary injection of adenoviral vectors transduced lining osteoblasts, osteocytes and cells within the bone marrow. Luciferase activity persisted within the injected femora and adjacent musculature for at least 3 weeks, and in the draining lymph nodes for 2 weeks. Transient, low level expression was present in the liver, but no luciferase was detected at any time in the lung or spleen. Intramedullary introduction of the IL-1Ra gene resulted in circulation of the corresponding protein at concentrations that peaked on day 3, and returned to baseline by day 12. Transfer of the IL-1Ra gene strongly reduced the early loss of bone mass occurring in response to ovariectomy. Furthermore, it completely inhibited the loss of matrix detected by histomorphometry at 5 weeks. The protective effect of this gene was not restricted to bones receiving intramedullary injection of the vector, but occurred in all bones that were evaluated. This proof of concept encourages further development of gene therapy approaches to the treatment of osteoporosis.

Potential role of direct adenoviral gene transfer in enhancing fracture repair.

Gene therapy has much to offer in the treatment of conditions in which it is necessary to increase the formation of bone. Nonunions, segmental defects, and aseptic loosening are examples of conditions where the local expression of genes that inhibit osteolysis and promote osteogenesis might be helpful. Studies in which one such possibility has been evaluated experimentally are described. These investigations used a surgically produced segmental defect in the femurs of New Zealand White rabbits as the model system. Adjacent muscle was fashioned around the defect to form a chamber into which adenoviral vectors were injected. High levels of transgene expression were found in the muscle surrounding the defect after injection of vectors carrying marker genes. Transgene expression also was seen in the cut ends of the bone and the scar tissue within the gap. No transgene expression was seen in the contralateral limb, spleen, or lung; transient, low levels of expression were found in the liver. Transgene expression declined with time, disappearing from all tissue but bone by Day 26; expression persisted in bone for at least 6 weeks. The control defects did not heal spontaneously. Injection of adenovirus carrying a human bone morphogenetic protein-2 complementary deoxyribonucleic acid led to healing of the segmental defect within 12 weeks, as judged by radiographic, histologic, and biomechanical criteria. Adenovirus carrying a human transforming growth factor-beta 1 complementary deoxyribonucleic acid showed signs of improved healing, but not to the extent seen with the bone morphogenetic protein-2 complementary deoxyribonucleic acid. This approach to therapy holds much promise as a novel means of promoting osteogenesis.