Endothelial cells enhance the in vivo bone-forming ability of osteogenic cell sheets

Addressing the problem of vascularization is of vital importance when engineering three-dimensional (3D) tissues. Endothelial cells are increasingly used in tissue-engineered constructs to obtain prevascularization and to enhance in vivo neovascularization. Rat bone marrow stromal cells were cultured in thermoresponsive dishes under osteogenic conditions with human umbilical vein endothelial cells (HUVECs) to obtain homotypic or heterotypic cell sheets (CSs). Cells were retrieved as sheets from the dishes after incubation at 20 °C. Monoculture osteogenic CSs were stacked on top of homotypic or heterotypic CSs, and subcutaneously implanted in the dorsal flap of nude mice for 7 days. The implants showed mineralized tissue formation under both conditions. Transplanted osteogenic cells were found at the new tissue site, demonstrating CS bone-inductive effect. Perfused vessels, positive for human CD31, confirmed the contribution of HUVECs for the neovascularization of coculture CS constructs. Furthermore, calcium quantification and expression of osteocalcin and osterix genes were higher for the CS constructs, with HUVECs demonstrating the more robust osteogenic potential of these constructs. This work demonstrates the potential of using endothelial cells, combined with osteogenic CSs, to increase the in vivo vascularization of CS-based 3D constructs for bone tissue engineering purposes.We would like to acknowledge Mariana T Cerqueira for the illustration in Figure 1. This study was supported by Formation of Innovation Center for Fusion of Advanced Technologies in the Special Coordination Funds for Promoting Science and Technology 'Cell Sheet Tissue Engineering Center (CSTEC)' and the Global CUE program, the Multidisciplinary Education and Research Center for Regenerative Medicine (MERCREM), from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. Financial support to RP Pirraco by the Portuguese Foundation for Science and Technology (FCT) through the PhD Grant SFRH/BD/44893/2008 is also acknowledged

Outcomes of surgical versus nonsurgical treatment for multiple rib fractures: A US hospital matched cohort database analysis

BACKGROUND Treatment for multiple rib fractures includes surgical stabilization of rib fractures (SSRF) or nonoperative management (NOM). Meta-analyses have demonstrated that SSRF results in faster recovery and lower long-term complication rates versus NOM. Our study evaluated postoperative outcomes for multiple rib fracture patients following SSRF versus NOM in a real-world, all-comer study design. METHODS Multiple rib fracture patients with inpatient admissions in the PREMIER hospital database from October 1, 2015, to September 30, 2020, were identified. Outcomes included discharge disposition, and 3- and 12-month lung-related readmissions. Demographics, comorbidities, concurrent injuries at index, Abbreviated Injury Scale and Injury Severity Scores, and provider characteristics were determined for all patients. Patients were excluded from the cohort if they had a thorax Abbreviated Injury Scale score of <2 (low severity patient) or a Glasgow Coma Scale score of ≤8 (extreme high severity patient). Stratum matching between SSRF and NOM patients was performed using fine stratification and weighting so that all patient data were kept in the final analysis. Outcomes were analyzed using generalized linear models with quasinormal distribution and logit links. RESULTS A total of 203,450 patients were included, of which 200,580 were treated with NOM and 2,870 with SSRF. Compared to NOM, patients with SSRF had higher rates of home discharge (62% SSRF vs. 58% NOM) and lower rates of lung-related readmissions (3 months, 3.1% SSRF vs. 4.0% NOM; 12 months, 6.2% SSRF vs. 7.6% NOM). The odds ratio (OR) for home or home health discharge in patients with SSRF versus NOM was 1.166 (95% confidence interval [CI], 1.073-1.266; p = 0.0002). Similarly, ORs for lung-related readmission at 3- and 12-month were statistically lower in the patients treated with SSRF versus NOM (OR [3 months], 0.764 [95% CI, 0.606-0.963]; p = 0.0227 and OR [12 months], 0.799 [95% CI, 0.657-0.971]; p = 0.0245). CONCLUSION Surgical stabilization of rib fractures results in greater odds of home discharge and lower rates of lung-related readmissions compared with NOM at 12 months of follow-up. LEVEL OF EVIDENCE Therapeutic/Care Management; Level III

Nail fixation of unstable trochanteric fractures with or without cement augmentation: A cost-utility analysis in the United States: Cost-utility of cement augmentation

Objectives: Recent clinical studies have shown favorable outcomes for cement augmentation for fixation of trochanteric fracture. We assessed the cost-utility of cement augmentation for fixation of closed unstable trochanteric fractures from the US payer's perspective. Methods: The cost-utility model comprised a decision tree to simulate clinical events over 1 year after the index fixation surgery, and a Markov model to extrapolate clinical events over patients’ lifetime, using a cohort of 1,000 patients with demographic and clinical characteristics similar to that of a published randomized controlled trial (age ≥75 years, 83 % female). Model outputs were discounted costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER) over a lifetime. Deterministic and probabilistic sensitivity analyses were performed to assess the impact of parameter uncertainty on results. Results: Fixation with augmentation reduced per-patient costs by $754.8 and had similar per-patient QALYs, compared to fixation without augmentation, resulting in an ICER of −$130,765/QALY. The ICER was most sensitive to the utility of revision surgery, mortality risk ratio after the second revision surgery, mortality risk ratio after successful index surgery, and mortality rate in the decision tree model. The probability that fixation with augmentation was cost-effective compared with no augmentation was 63.4 %, 58.2 %, and 56.4 %, given a maximum acceptable ceiling ratio of $50,000,$100,000, and $150,000 per QALY gained, respectively. Conclusion: Fixation with cement augmentation was the dominant strategy, driven mainly by reduced costs. These results may support surgeons in evidence-based clinical decision making and may be informative for policy makers regarding coverage and reimbursement

Cost-Effectiveness of Cement Augmentation Versus No Augmentation for the Fixation of Unstable Trochanteric Fractures

Background:A previous randomized controlled trial (RCT) demonstrated a trend toward a reduced risk of implant-related revision surgery following fixation with use of a Proximal Femoral Nail Antirotation (PFNA) with TRAUMACEM V+ Injectable Bone Cement augmentation versus no augmentation in patients with unstable trochanteric fractures. To determine whether this reduced risk may result in long-term cost savings, the present study assessed the cost-effectiveness of TRAUMACEM V+ cement augmentation versus no augmentation for the fixation of unstable trochanteric fractures from the German health-care payer's perspective.Methods:The cost-effectiveness model comprised 2 stages: a decision tree simulating clinical events, costs, and utilities during the first year after the index procedure and a Markov model extrapolating clinical events, costs, and utilities over the patient's lifetime. Sources of model parameters included the previous RCT, current literature, and administrative claims data. Outcome measures were incremental costs (in 2020 Euros), incremental quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs). Model uncertainty was assessed with deterministic and probabilistic sensitivity analyses.Results:The base-case analysis showed that fixation with cement augmentation was the dominant strategy as it was associated with cost savings (50.3/patient) and QALY gains (0.01 QALY/patient). Major influential parameters for the ICER were the utility of revision, rates of revision surgery within the first year after fixation surgery, and the costs of augmentation and revision surgery. Probabilistic sensitivity analyses demonstrated that estimates of cost savings were more robust than those of increased QALYs (66.4% versus 52.7% of the simulations). For a range of willingness-to-pay thresholds from 0 to 50,000, the probability of fixation with cement augmentation being cost-effective versus no augmentation remained above 50%.Conclusions:Fixation with use of cement augmentation dominated fixation with no augmentation for unstable trochanteric fractures, resulting in cost savings and QALY gains. Given the input parameter uncertainties, future analyses are warranted when long-term costs and effectiveness data for cement augmentation are available.Level of Evidence:Economic and Decision Analysis Level II. See Instructions for Authors for a complete description of levels of evidence

A new technique for seeding chondrocytes onto solvent-preserved human meniscus using the chemokinetic effect of recombinant human bone morphogenetic protein-2

Many investigators are currently studying the use of decellularized tissue allografts from human cadavers as scaffolds onto which patients’ cells could be seeded, or as carriers for genetically engineered cells to aid cell transplantation. However, it is difficult to seed cells onto very dense regular connective tissue which has few interstitial spaces. Here, we discuss the development of a chemotactic cell seeding technique using solvent-preserved human meniscus. A chemokinetic response to recombinant human bone morphogenetic protein-2 (rhBMP-2) was observed in a monolayer culture of primary chondrocytes derived from femoral epiphyseal cartilage of 2-day-old rats. The rhBMP-2 significantly increased their migration upto 10 ng/ml in a dose-dependent manner. When tested with solvent-preserved human meniscus as a scaffold, which has few interstitial spaces, rhBMP-2 was able to induce chondrocytes to migrate into the meniscus. After a 3-week incubation, newly-formed cartilaginous extracellular matrix was synthesized by migrated chondrocytes throughout the meniscus, down to a depth of 3 mm. These findings demonstrate that rhBMP-2 may be a natural chemokinetic factor in vivo, which induces migration of proliferative chondrocytes into the narrow interfibrous spaces. Our results suggest a potential application of rhBMP-2 for the designed distribution of chondrocytes into a scaffold to be used for tissue engineering

Kinetochore fiber formation in animal somatic cells : dueling mechanisms come to a draw

Author Posting. © The Author, 2005. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Chromosoma 114 (2005): 310-318, doi:10.1007/s00412-005-0028-2.The attachment to and movement of a chromosome on the mitotic spindle is mediated by the formation of a bundle of microtubules (MTs) that tethers the kinetochore on the chromosome to a spindle pole. The origin of these “kinetochore fibers” (K-fibers) has been investigated for over 125 years. As noted in 1944 by Schrader, there are only three possible ways to form a K-fiber: either it a) grows from the pole until it contacts the kinetochore; b) grows directly from the kinetochore; or c) it forms as a result of an interaction between the pole and the chromosome. Since Schrader’s time it has been firmly established that K-fibers in centrosome-containing animal somatic cells form as kinetochores capture MTs growing from the spindle pole (route a). It is now similarly clear that in cells lacking centrosomes, including plants and many animal oocytes, K-fibers “self-assemble” from MTs generated by the chromosomes (route b). Can animal somatic cells form K-fibers in the absence of centrosomes by the “self-assembly” pathway? In 2000 the answer to this question was shown to be a resounding “yes”. With this result, the next question became whether the presence of a centrosome normally suppresses K-fiber self-assembly, or if this route works concurrently with centrosome-mediated K-fiber formation. This question, too, has recently been answered: observations on untreated live animal cells expressing GFP-tagged tubulin clearly show that kinetochores can nucleate the formation of their associated MTs in the presence of functional centrosomes. The concurrent operation of these two “dueling” routes for forming K-fibers in animals helps explain why the attachment of kinetochores and the maturation of K-fibers occur as quickly as it does on all chromosomes within a cell.The work is sponsored by NIH grant GMS 40198

A biomaterials approach to influence stem cell fate in injectable cell-based therapies

Background Numerous stem cell therapies use injection-based administration to deliver high-density cell preparations. However, cell retention rates as low as 1% have been observed within days of transplantation. This study investigated the effects of varying administration and formulation parameters of injection-based administration on cell dose recovery and differentiation fate choice of human mesenchymal stem cells. Methods The impact of ejection rate via clinically relevant Hamilton micro-syringes and biomaterial-assisted delivery was investigated. Cell viability, the percentage of cell dose delivered as viable cells, proliferation capacity as well as differentiation behaviour in bipotential media were assessed. Characterisation of the biomaterial-based cell carriers was also carried out. Results A significant improvement of in-vitro dose recovery in cells co-ejected with natural biomaterials was observed, with ejections within 2% (w/v) gelatin resulting in 87.5 ± 14% of the cell dose being delivered as viable cells, compared to 32.2 ± 19% of the dose ejected in the commonly used saline vehicle at 10 μl/min. Improvement in cell recovery was not associated with the rheological properties of biomaterials utilised, as suggested by previous studies. The extent of osteogenic differentiation was shown to be substantially altered by choice of ejection rate and cell carrier, despite limited contact time with cells during ejection. Collagen type I and bone-derived extracellular matrix cell carriers yielded significant increases in mineralised matrix deposited at day 21 relative to PBS. Conclusions An enhanced understanding of how administration protocols and biomaterials influence cell recovery, differentiation capacity and choice of fate will facilitate the development of improved administration and formulation approaches to achieve higher efficacy in stem cell transplantation

International Consensus Statement on Rhinology and Allergy: Rhinosinusitis

Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods: ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion: This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS