Enhanced osteopontin expression in a murine model of allergen-induced airway remodelling

BACKGROUND

Airway remodelling is a central pathophysiological feature of chronic asthma. A wide variety of cytokines and growth factors are likely to be involved in the development of airway remodelling. Osteopontin (OPN) is a cytokine with pro-fibrotic properties; however, its role in airway remodelling in asthma has not been explored.

OBJECTIVE

To determine the expression and cellular sources of OPN in a murine model of chronic allergen-induced airway remodelling.

METHODS

BALB/c mice were sensitized and exposed to ovalbumin (OVA) or saline inhalations for 5 weeks and killed 24 h after the last inhalation. The following parameters of inflammation and remodelling were assessed: differential cell counts in bronchoalveolar lavage (BAL) fluid lung collagen content (colorimetric biochemical assay) and peribronchial smooth muscle content (immunohistochemistry, followed by image analysis). OPN expression in BAL and lung tissue was determined by PCR and ELISA. The cellular source and distribution of OPN were evaluated by immunohistochemistry and immunofluorescence.

RESULTS

OPN expression is up-regulated in lung tissue and in BAL fluid of OVA-treated mice and correlates with collagen content and peribronchial smooth muscle area. In addition, OPN significantly increases collagen deposition in vitro in a murine lung cell line. Cells producing OPN include the airway epithelium and cells of the submucosal inflammatory infiltrate (T cells, eosinophils, and macrophages). Positive staining for OPN was also observed in bronchial tissue from human asthmatic subjects.

CONCLUSION

OPN expression in the lungs is increased in a murine model of allergen-induced chronic airway remodelling, suggesting a role for this cytokine in airway remodelling in asthma.

Depletion of Normal and Malignant B cells with a CD37-specific SMIP molecule

3063

Background: CD37 is a member of the tetraspanin family expressed at high levels by normal mature B cells and by most B cell malignancies. Previously, an antibody to CD37 has been labeled with 131I and tested in clinical trials for therapy of NHL. Treatment with 131I-MB-1, resulted in durable tumor remissions in patients lasting from 4 to 11 months (Press OW, Eary JF, Badger CC, et al. Treatment of refractory non-Hodgkin’s lymphoma with radiolabeled MB-1 (anti-CD37) antibody. J Clin Oncol. 1989;7:1027–1038). Here we assess the functional properties and therapeutic potential of a small modular immunopharmaceutical (SMIP) targeting CD37. Methods: Growth arrest and apoptosis of B lymphoma cell lines was assessed. ADCC activity was evaluated using BJAB targets and human peripheral blood mononuclear cells (PBMC) effectors. Drug-drug interactions were assessed by the Combination Index method. In vivo studies were performed utilizing established human B cell tumor xenografts in nude mice. Results: A CD37-directed SMIP drug candidate mediated growth arrest, apoptosis and ADCC, but not CDC, towards B lymphoma cell lines. The protein showed significant anti-tumor activity in a mouse xenograft model, and selectively depleted normal human B cells in short term cultures of PBMC. When combined with rituximab, the molecule increased apoptosis, C1q binding, and C’ dependent target cell death in vitro, and increased anti-tumor activity in vivo in a xenograft model. Conclusions: In vitro and in vivo characterization of the CD37-targeted SMIP drug suggest a potent capacity to eliminate target cells through combined effects of direct target cell signaling and effector cell recruitment. CD37-mediated growth was synergistic with standard chemotherapies in vitro and showed additive in vivo activity with CD20-targeted therapy. On the basis of these data CD37-directed SMIP therapy is being developed for clinical evaluation against B cell malignancies.

No significant financial relationships to disclose.

Die Bedeutung der Gleitpaarung beim jüngeren Endoprothesenpatienten

The success and long-term survival rates of modern joint arthroplasty leads to a high patient satisfaction and, together with its technical improvements, has broadened the indications to an increasingly younger population. Limitations to the established systems are the long-term survival rates, which are mainly influenced by wear of the articulating parts and the resulting problems. Beside "classic" long-stemmed cemented shafts articulating with metal against polyethylene, short-stemmed or cup designs with a hard-hard self pairing are increasingly used in total hip arthroplasty. This paper reflects the current state of the art in joint arthroplasty for younger patients with the focus on wear couples and discusses future perspectives. Special interest is focused on the advantages and disadvantages of ceramic bearings, problems with allergies to implant components and the design of endoprostheses with regard to avoidance of impingement.

[Failure analysis of total knee replacement. Basics and methodological aspects of the damage analysis]

Possible causes for failure of total knee endoprostheses represent wear, malpositioning, maldimensioning and inadequate design of the implant components, manufacturing defects, material fatigue, corrosion, overloading, infection, and allergy against implant materials. There is a broad spectrum of methodical approaches for the analysis of failure cases. Substantial information for the damage analysis is provided by clinical and intraoperative findings, photo documentation, radiographic course as well as all-solid, physical and histological investigations. Principal purposes of damage analysis are the avoidance of further damage events and the gain of information for improvement of implant design and material as well as the optimisation of the biocompatibility of implants and wear products. Both a detection system of incidents and implant failures as well as a complete data collection enables early identification of system-specific, accumulated cases of implant failure.

Assessment of cup position from plain radiographs: impact of pelvic tilting

The acetabular cup position after total hip arthroplasty (THA) regarding its inclination and version angles are influential parameters concerning the postoperative range of motion and dislocation stability. Standard anterior-posterior X-rays remain an important diagnostic instrument to observe the postoperative outcome and to secure quality control after THA, where an optimal positioning of the patient is recommended when taking these X-rays. The purpose of this preliminary study was to determine the effect of pelvic tilting regarding the positioning calculation of the acetabular cup from standard radiographs using a modified method according to Pettersson et al. (Acta Radiol Diagn, 23:259-263, 1982). In our model experiment, we were able to show that pelvic tilting to either side causes a considerable difference between the radiographic and calculated version angles following approximately linear functions. However, pelvic tilting to either side, leads, regarding the calculation of the inclination, to an average deviation between radiographic and calculated inclination angles less than 2 degrees .

A novel test method for evaluation of the abrasive wear behaviour of total hip stems at the interface between implant surface and bone cement

After total hip replacement, some cemented titanium stems show above-average early loosening rates. Increased release of wear particles and resulting reaction of the peri-prosthetic tissue were considered responsible. The objective was to develop a test method for analysing the abrasive wear behaviour of cemented stems and for generating wear particles at the interface with the bone cement.

By means of the novel test device, cemented hip stems with different designs, surface topographies and material compositions using various bone cements could be investigated. Before testing, the cemented stems were disconnected from the cement mantle to simulate the situation of stem loosening (debonding). Subsequently, constant radial contact pressures were applied on to the stem surface by a force-controlled hydraulic cylinder. Oscillating micromotions of the stem (± 250 μm; 3 × 106cycles; 5 Hz) were carried out at the cement interface initiating the wear process.

The usability of the method was demonstrated by testing geometrically identical Ti-6A1-7Nb and Co-28Cr-6Mo hip stems ( n = 12) with definite rough and smooth surfaces, combined with commercially available bone cement containing zirconium oxide particles. Under identical frictional conditions with the rough shot-blasted stems, clearly more wear particles were generated than with the smooth stems, whereas the material composition of the hip stems had less impact on the wear behaviour.

Evaluierung des Fügeverhaltens und der Rückhaltekräfte von Schnapp-Pfannen für den künstlichen Hüftgelenkersatz / Evaluation of the assembling and retention forces of constraint liners for total hip replacement

Dislocation is a severe complication after total hip replacement which may cause revision surgery in some cases. The use of constraint inserts that are coupled to the femoral head by a snapping mechanism provides an opportunity for treatment of recurrent dislocations. This study was aimed to investigate the assembling and retention forces of a specific constraint liner. Using a universal testing machine the assembling forces were determined for head sizes of 28 and 32 mm and the clinically mostly used as well as the maximum cup size. Subsequently, under variation of load direction and pull-out velocity the retention forces were investigated. For primary assembly of the head the required compressive forces were in a range from 197 N and 283 N depending on head and cup size (each size n = 3). Repeated assembly led to a decrease of these forces up to 29%. The retention forces always were slightly below the assembling forces, i. e. forces to remove the heads from the inserts were between 183 N and 230 N (each size n = 3). Repeated disconnection caused a decrease of the retention forces up to 16%. An increase of load velocity as well as an oblique load direction resulted in an enhancement of the retention forces. For all investigated implant sizes the retention force for the femoral head was approximately ten-times less than the interface strength between the insert and the metal-back. In case of correct implant handling the risk of disconnection between the tested constraint insert and the corresponding metal-back has not to be considered in clinical practice.

Experimentelle Analyse von neutralen, asymmetrischen und Schnapp-Pfannen für die Hüftendoprothetik

AIM

Recurrent dislocation after total hip replacement is a severe complication, which requires specific treatment and implants. The purpose of the present study was to compare a constraint liner with an elevated rim and standard liner regarding their range of motion and dislocation stability.

METHOD

With a test device, range of motion until impingement (ROM (Imp)) and dislocation (ROM (Lux)) were experimentally analyzed using the above-mentioned insert types of a commercial total hip system. On the basis of movement combinations associated with dislocation, the ROM was determined. Further measuring parameter was the resisting moment against subluxation of the femoral head.

RESULTS

The constraint liners showed clear restriction of the movements "internal rotation combined with 90 degrees flexion and 0 degrees adduction" and "external rotation with 10 degrees extension and 15 degrees adduction" of up to 20 degrees compared to the neutral liner. ROM (Imp) was only decreased by about 8 degrees with the elevated-rim liner. The constraint liners revealed the highest resisting moments in subluxation, however, at adequate orientation in the acetabular cup the elevated-rim liners provided a higher ROM (Lux) of up to 12 degrees. Both designs were superior to the neutral liner at retroversion and steep cup position regarding resisting moment and ROM (Lux).

CONCLUSION

In case of insufficient soft tissue tension the use of constraint liners may increase the dislocation stability, however, in contrast to elevated-rim liners the impingement-free movement interval is clearly reduced. Thus, material damage and high shear stress in the bone interface can result. Therefore, constraint liners should only be used in exceptional cases.

The COSTIM bioassay: a novel potency test for dendritic cells

The utility of dendritic cells (DCs) in experimental immunotherapy has driven significant advances in the manufacture of these cells. They are increasingly prepared in vitro for use in clinical trials of human disease, particularly cancer. Thus, it has become imperative that, in concert with other quality control measures, a potency test be employed for lot (batch)-release testing of DC products, both in preclinical studies and human clinical trials. The mixed lymphocyte reaction (MLR) assay has served as a 'gold standard' for evaluating the functional ability of antigen presenting cells. Alternatively, some researchers also employ immunophenotyping, a test unrelated to cellular function, as a potency-determining test. We have developed a novel method named the 'COSTIM bioassay', which, as we describe in this paper, is suitable for quality control or lot-release testing. In this method T-cells are stimulated with a sub-optimal amount of anti-CD3 antibody, such that they remain unable to proliferate unless a source of co-stimulation (accessory cells, such as DC) is added to the culture. Thus, the COSTIM bioassay is a functional test that selectively measures co-stimulatory activity, or functional potency. This method takes less than 2 days for completion and assures better quality control than the MLR.