Vitamin E-diffused liners show less head penetration than cross-linked polyethylene liners in total hip arthroplasty: a ten-year multi-arm randomized trial.

Aims: The primary outcome was investigating differences in wear, as measured by femoral head penetration, between cross-linked vitamin E-diffused polyethylene (vE-PE) and cross-linked polyethylene (XLPE) acetabular component liners and between 32 and 36 mm head sizes at the ten-year follow-up. Secondary outcomes included acetabular component migration and patient-reported outcome measures (PROMs) such as the EuroQol five-dimension questionnaire, 36-Item Short-Form Health Survey, Harris Hip Score, and University of California, Los Angeles Activity Scale (UCLA). Methods: A single-blinded, multi-arm, 2 × 2 factorial randomized controlled trial was undertaken. Patients were recruited between May 2009 and April 2011. Radiostereometric analyses (RSAs) were performed from baseline to ten years. Of the 220 eligible patients, 116 underwent randomization, and 82 remained at the ten-year follow-up. Eligible patients were randomized into one of four interventions: vE-PE acetabular liner with either 32 or 36 mm femoral head, and XLPE acetabular liner with either 32 or 36 mm femoral head. Parameters were otherwise identical except for acetabular liner material and femoral head size. Results: A total of 116 patients participated, of whom 77 were male. The median ages of the vE-PE 32 mm and 36 mm groups were 65 (interquartile range (IQR) 57 to 67) and 63 years (IQR 56 to 66), respectively, and of the XLPE 32 mm and 36 mm groups were 64 (IQR 58 to 66) and 61 years (IQR 54 to 66), respectively. Mean total head penetration was significantly lower into vE-PE acetabular liner groups than into XLPE acetabular liner groups (-0.219 mm (95% confidence interval -0.348 to -0.090); p = 0.001). There were no differences in wear according to head size, acetabular component migration, or PROMs, except for UCLA. There were no cases of aseptic loosening or failures requiring revision at long-term follow-up. Conclusion: Significantly lower wear was observed in vE-PE acetabular liners than in XLPE acetabular liners. No difference in wear was observed between different head size or PROMs except for the UCLA at ten years.

TransCon IL-2 ß/γ: a novel long-acting prodrug with sustained release of an IL-2Rß/γ-selective IL-2 variant with improved pharmacokinetics and potent activation of cytotoxic immune cells for the treatment of cancer.

BACKGROUND: Recombinant interleukin-2 (IL-2, aldesleukin) is an approved cancer immunotherapy but causes severe toxicities including cytokine storm and vascular leak syndrome (VLS). IL-2 promotes antitumor function of IL-2Rß/γ+ natural killer (NK) cells and CD8+, CD4+ and gamma delta (γδ) T cells. However, IL-2 also potently activates immunosuppressive IL-2Rα+ regulatory T cells (Tregs) and IL-2Rα+ eosinophils and endothelial cells, which may promote VLS. Aldesleukin is rapidly cleared requiring frequent dosing, resulting in high Cmax likely potentiating toxicity. Thus, IL-2 cancer immunotherapy has two critical drawbacks: potent activation of undesired IL-2Rα+ cells and suboptimal pharmacokinetics with high Cmax and short half-life. METHODS: TransCon IL-2 ß/γ was designed to optimally address these drawbacks. To abolish IL-2Rα binding yet retain strong IL-2Rß/γ activity, IL-2 ß/γ was created by permanently attaching a small methoxy polyethylene glycol (mPEG) moiety in the IL-2Rα binding site. To improve pharmacokinetics, IL-2 ß/γ was transiently attached to a 40 kDa mPEG carrier via a TransCon (transient conjugation) linker creating a prodrug, TransCon IL-2 ß/γ, with sustained release of IL-2 ß/γ. IL-2 ß/γ was characterized in binding and primary cell assays while TransCon IL-2 ß/γ was studied in tumor-bearing mice and cynomolgus monkeys. RESULTS: IL-2 ß/γ demonstrated selective and potent human IL-2Rß/γ binding and activation without IL-2Rα interactions. TransCon IL-2 ß/γ showed slow-release pharmacokinetics with a low Cmax and a long (>30 hours) effective half-life for IL-2 ß/γ in monkeys. In mouse tumor models, TransCon IL-2 ß/γ promoted CD8+ T cell and NK cell activation and antitumor activity. In monkeys, TransCon IL-2 ß/γ induced robust activation and expansion of CD8+ T cells, NK cells and γδ T cells, relative to CD4+ T cells, Tregs and eosinophils, with no evidence of cytokine storm or VLS. Similarly, IL-2 ß/γ enhanced proliferation and cytotoxicity of primary human CD8+ T cells, NK cells and γδ T cells. SUMMARY: TransCon IL-2 ß/γ is a novel long-acting prodrug with sustained release of an IL-2Rß/γ-selective IL-2. It has remarkable and durable pharmacodynamic effects in monkeys and potential for improved clinical efficacy and tolerability compared with aldesleukin. TransCon IL-2 ß/γ is currently being evaluated in a Phase 1/2 clinical trial (NCT05081609).

Revision Risk of Total Hip Arthroplasty With Vitamin E Doped Liners: Results From the Danish Hip Arthroplasty Register.

BACKGROUND: Vitamin E-doped cross-linked polyethylene (VEPE) liners were introduced in total hip arthroplasty (THA) to reduce wear and risk of aseptic loosening and liner fracture. We report this nationwide population-based study to investigate the safety of VEPE liners for THA compared to cross-linked annealed or remelted polyethylene (XLPE). METHODS: We included THAs from The Danish Hip Arthroplasty Register from January 1, 2008 to June 30, 2019, with uncemented cup, VEPE or XLPE liner, and metal or ceramic head. The outcome was revision due to (1) polyethylene-related endpoints (aseptic loosening, granuloma, osteolysis, or liner fractures) and (2) other endpoints. RESULTS: A total of 110,803 THAs were assessed for eligibility and 53,842 THAs (46,645 patients) were included in the study: 5069 (9.4%) THAs with a VEPE liner and 48,773 (91.6%) with a XLPE liner. Median observation time was 5.48 (interquartile range 3.80-7.15) years for VEPE and 4.85 (interquartile range 2.68-7.76) for XLPE. VEPE had a lower risk of revision for polyethylene-related endpoints compared to XLPE (hazard ratio [HR] 0.60, 95% confidence interval 0.36-0.98) during complete follow-up. THAs with VEPE liners were associated with increased risk of any revision within the first 3 months (HR 1.62, 1.36-1.94), revision recorded as aseptic loosening within 3 months (HR 4.46, 2.26-8.80), and periprosthetic fracture within 3 months (HR 2.57, 1.98, 3.33). CONCLUSION: VEPE liners had a lower risk of revision due to polyethylene-related endpoints, but a higher risk of all-cause revision within 3 months.

Vitamin E-doped total hip arthroplasty liners show similar head penetration to highly cross-linked polyethylene at five years: a multi-arm randomized controlled trial.

AIMS: The most frequent indication for revision surgery in total hip arthroplasty (THA) is aseptic loosening. Aseptic loosening is associated with polyethylene liner wear, and wear may be reduced by using vitamin E-doped liners. The primary objective of this study was to compare proximal femoral head penetration into the liner between a) two cross-linked polyethylene (XLPE) liners (vitamin E-doped (vE-PE)) versus standard XLPE liners, and b) two modular femoral head diameters (32 mm and 36 mm). METHODS: Patients scheduled for a THA were randomized to receive a vE-PE or XLPE liner with a 32 mm or 36 mm metal head (four intervention groups in a 2 × 2 factorial design). Head penetration and acetabular component migration were measured using radiostereometric analysis at baseline, three, 12, 24, and 60 months postoperatively. The Harris Hip Score, University of California, Los Angeles (UCLA) Activity Score, EuroQol five-dimension questionnaire (EQ-5D), and 36-Item Short-Form Health Survey questionnaire (SF-36) were assessed at baseline, three, 12, 36, and 60 months. RESULTS: Of 220 screened patients, 127 were included in this study. In all, 116 received the allocated intervention, and 94 had their results analyzed at five years. Head penetration was similar between liner materials and head sizes at five years, vE-PE versus XLPE was -0.084 mm (95% confidence interval (CI) -0.173 to 0.005; p = 0.064), and 32 mm versus 36 mm was -0.020 mm (95% CI -0.110 to 0.071; p = 0.671), respectively. No differences were found in acetabular component migration or in the patient-reported outcome measures. CONCLUSION: No significant difference in head penetration was found at five years between vE-PE and XLPE liners, nor between 32 mm and 36 mm heads. Cite this article: Bone Joint J 2020;102-B(10):1303-1310.

Vascular endothelial growth factor for in vivo bone formation: A systematic review.

BACKGROUND: To achieve optimal bone formation one of the most influential parameters has been mentioned to be adequate blood supply. Vascular endothelial growth factor (VEGF) is hereby of particular interest in bone regeneration, because of its primary ability to induce neovascularization and chemokine affection for endothelial cells (EC), and is considered to be the main regulator of vascular formation. However, the growth factor has yet to be implemented in a clinical setting in orthopaedic intervention surgery. We hypothesised that the development of VEGF in vivo for bone formation in the last decade had progressed towards clinical application since the latest systematic review from 2008. OBJECTIVE: This systematic review recapped the last 13 years of in vivo bone regeneration using vascular endothelial growth factor (VEGF). METHOD: A total of 1374 articles were identified using the PubMed search string (vegf or "vascular endothelial growth factor") and (osteogen∗ or "bone formation" or "bone regeneration"). By 3 selection phases 24 published articles were included by the criteria of being in vivo, using only VEGF for bone formation, published after 2007 and written in English. Articles in vitro, written in different languages than English and older than 2007 was excluded. The most recent systematic review on this subject was published in 2008, with the latest included study from 01 to 11-2007. All included studies were classified based on animal, type of defect, scaffold, control group, type of VEGF, release rate, dosage of VEGF, time of evaluation and results. Each study was evaluated for risk of bias by modified CAMARADES quality assessment for the use in experimental animal studies. The score was calculated by peer review journal publication, use of control group, randomisation of groups, justified VEGF dosage, blinding of results, details on animal model, sample size calculation, comply with ethics and no conflict of interest. RESULTS: No clinical trials or human application studies were obtained from our search. Experimentally, 11 articles using solely VEGF for bone formation had a group or a timepoint significantly better than the corresponding control group. 18 articles revealed no significant difference of VEGF compared to the control group and 1 article reported a significant decreased bone growth using VEGF compared to control. CONCLUSION: Based on these results no clinical studies have yet been performed. However, indications in the best use of VEGF from experimental studies could be made towards that the optimal release is within the first three weeks, in defect models, with the best effect before eight weeks. Future designs should incorporate this with standardised and reproducible models for verification towards clinical practice. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: This systematic review aims to assess the existing literature to focus on methodologies and outcomes that can provide future knowledge regarding the solitary use of VEGF for bone regeneration in a clinical setting.

Optimizing combination of vascular endothelial growth factor and mesenchymal stem cells on ectopic bone formation in SCID mice.

INTRODUCTION: Insufficient blood supply may limit bone regeneration in bone defects. Vascular endothelial growth factor (VEGF) promotes angiogenesis by increasing endothelial migration. This outcome, however, could depend on time of application. Sheep mesenchymal stem cells (MSCs) in severe combined immunodeficient (SCID) mice were used in this study to evaluate optimal time points for VEGF stimulation to increase bone formation. METHODS: Twenty-eight SCID (NOD.CB17-Prkdcscid /J) mice had hydroxyapatite granules seeded with 5 × 105 MSCs inserted subcutaneous. Pellets released VEGF on days 1-7, days 1-14, days 1-21, days 1-42, days 7-14, and days 21-42. After 8 weeks, the implant-bone-blocks were harvested, paraffin embedded, sectioned, and stained with both hematoxylin and eosin (HE) and immunohistochemistry for human vimentin (hVim) staining. Blood samples were collected for determination of bone-related biomarkers in serum. RESULTS: The groups with 5 × 105 MSCs and VEGF stimulation on days 1-14 and days 1-21 showed more bone formation when compared to the control group of 5 × 105 MSCs alone (p < 0.01). Serum biomarkers had no significant values. The hVim staining confirmed the ovine origin of the observed ectopic bone formation. CONCLUSION: Optimal bone formation of MSCs was reached when stimulating with VEGF during the first 14 or 21 days after surgery. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3326-3332, 2017.

Bone Formation by Sheep Stem Cells in an Ectopic Mouse Model: Comparison of Adipose and Bone Marrow Derived Cells and Identification of Donor-Derived Bone by Antibody Staining.

Background. Scaffolds for bone tissue engineering (BTE) can be loaded with stem and progenitor cells (SPC) from different sources to improve osteogenesis. SPC can be found in bone marrow, adipose tissue, and other tissues. Little is known about osteogenic potential of adipose-derived culture expanded, adherent cells (A-CEAC). This study compares in vivo osteogenic capacity between A-CEAC and bone marrow derived culture expanded, adherent cells (BM-CEAC). Method. A-CEAC and BM-CEAC were isolated from five female sheep and seeded on hydroxyapatite granules prior to subcutaneous implantation in immunodeficient mice. The doses of cells in the implants were 0.5 × 106, 1.0 × 106, or 1.5 × 106 A-CEAC and 0.5 × 106 BM-CEAC, respectively. After eight weeks, bone volume versus total tissue volume (BV/TV) was quantified using histomorphometry. Origin of new bone was assessed using human vimentin (HVIM) antibody staining. Results. BM-CEAC yielded significantly higher BV/TV than any A-CEAC group, and differences between A-CEAC groups were not statistically significant. HVIM antibody stain was successfully used to identify sheep cells in this model. Conclusion. A-CEAC and BM-CEAC were capable of forming bone, and BM-CEAC yielded significantly higher BV/TV than any A-CEAC group. In vitro treatment to enhance osteogenic capacity of A-CEAC is suggested for further research in ovine bone tissue engineering.

Global gene expression in Escherichia coli biofilms.

It is now apparent that microorganisms undergo significant changes during the transition from planktonic to biofilm growth. These changes result in phenotypic adaptations that allow the formation of highly organized and structured sessile communities, which possess enhanced resistance to antimicrobial treatments and host immune defence responses. Escherichia coli has been used as a model organism to study the mechanisms of growth within adhered communities. In this study, we use DNA microarray technology to examine the global gene expression profile of E. coli during sessile growth compared with planktonic growth. Genes encoding proteins involved in adhesion (type 1 fimbriae) and, in particular, autoaggregation (Antigen 43) were highly expressed in the adhered population in a manner that is consistent with current models of sessile community development. Several novel gene clusters were induced upon the transition to biofilm growth, and these included genes expressed under oxygen-limiting conditions, genes encoding (putative) transport proteins, putative oxidoreductases and genes associated with enhanced heavy metal resistance. Of particular interest was the observation that many of the genes altered in expression have no current defined function. These genes, as well as those induced by stresses relevant to biofilm growth such as oxygen and nutrient limitation, may be important factors that trigger enhanced resistance mechanisms of sessile communities to antibiotics and hydrodynamic shear forces.

Antigen 43-mediated autotransporter display, a versatile bacterial cell surface presentation system.

Antigen 43 (Ag43), a self-recognizing outer membrane protein of Escherichia coli, has been converted into an efficient and versatile tool for surface display of foreign protein segments. Ag43 is an autotransporter protein characterized by the feature that all information required for transport to the outer membrane and secretion through the cell envelope is contained within the protein itself. Ag43 consists of two subunits (alpha and beta), where the beta-subunit forms an integral outer membrane translocator to which the alpha-subunit is noncovalently attached. The simplicity of the Ag43 system makes it ideally suited as a surface display scaffold. Here we demonstrate that the Ag43 alpha-module can accommodate and display correctly folded inserts and has the ability to display entire functional protein domains, exemplified by the FimH lectin domain. The presence of heterologous cysteine bridges does not interfere with surface display, and Ag43 chimeras are correctly processed into alpha- and beta-modules, offering optional and easy release of the chimeric alpha-subunits. Furthermore, Ag43 can be displayed in many gram-negative bacteria. This feature is exploited for display of our chimeras in an attenuated Salmonella strain.