Aloenxertos criopreservados no tratamento de defeitos osteocartilagíneos

A reparação cirúrgica dos defeitos da cartilagem articular representa uma das situações mais difíceis de tratar em Ortopedia. Os aloenxertos osteocartilagíneos devem ser reservados para a reconstrução de defeitos significativos envolvendo cartilagem e osso (> 3 cm de diâmetro e 1 cm de profundidade), isto é, nas lesões demasiado extensas para serem corrigidas através de outras técnicas. Os aloenxertos osteocartilagíneos criopreservados apresentam vantagens em relação aos frescos, que incluem uma maior segurança microbiológica, menor capacidade imunogénica ligada ao tecido ósseo e estão disponíveis em maior número. No entanto, os aloenxertos osteocartilagíneos frescos mantêm uma maior viabilidade condrocitária e, por isso, oferecem um melhor desempenho clínico. Embora permita recuperar um maior número de condrócitos vivos, a utilização de crioprotectores está ainda longe de originar a protecção completa e eficaz de todos os condrócitos presentes na cartilagem articular, o que compromete significativamente o desempenho clínico a médio ou a longo termo dos aloenxertos osteocartilagíneos criopreservados. A combinação de um potente agente crioprotector como parece ser a arbutina, com meios mecânicos capazes de exercer uma pressão adequada poderá ser a chave para se alcançar uma percentagem significativa de condrócitos vivos após o processo de descongelação da cartilagem criopreservada e, assim, poderá assegurar a eficácia clínica, a médio e longo prazos, dos aloenxertos osteocartilagíneos criopreservados

Cortical strut allografting in reconstructive orthopaedic surgery

Many approaches are used in the repair of skeletal defects in reconstructive orthopaedic surgery, and bone grafting is involved in virtually every procedure. Autografting remains the gold standard for replacing bone loss. However, the limited amount of bone that can be harvested and the morbidity associated with that procedure are major constraints to the clinical use of autografts. In contrast, bone allografts can be used in any kind of surgery, whether involving minor defects or major bone loss. Cortical strut allografts unite to host bone through callus formation, restoring bone stock and can be used as an onlay biological plate. These struts can be made from hemicylinders of tibia being fixed to host bone by circumferential metallic cables or by screws. The purpose of this study was to analyze the radiographic outcomes of twelve cryopreserved cortical onlay strut allografts, used in a group of nine patients, for revision hip arthroplasty of the femoral side, to stabilize femoral periprosthetic fractures, to reinforce poor cortical bone and to treat one atrophic femoral nonunion. The average follow-up period was 4.3 years (range, 1.6 to 9 years). No fractures, nonunions or progressive resorption of the bone allografts were observed. All struts were incorporated to the native femur with minimal resorption, within the first year after surgery. There was no failure of any of the allograft reconstructions.The results obtained show that cortical onlay strut allografts, either alone or in conjunction with metallic plate or cancellous bone allografts, are a valuable adjunct for reconstructive surgery of the hip and to treat atrophic femoral nonunion

Role of glucose as a modulator of anabolic and catabolic gene expression in normal and osteoarthritic human chondrocytes

Cartilage matrix homeostasis involves a dynamic balance between numerous signals that modulate chondrocyte functions. This study aimed at elucidating the role of the extracellular glucose concentration in modulating anabolic and catabolic gene expression in normal and osteoarthritic (OA) human chondrocytes and its ability to modify the gene expression responses induced by pro-anabolic stimuli, namely Transforming Growth Factor-β (TGF). For this, we analyzed by real time RT-PCR the expression of articular cartilage matrix-specific and non-specific genes, namely collagen types II and I, respectively. The expression of the matrix metalloproteinases (MMPs)-1 and -13, which plays a major role in cartilage degradation in arthritic conditions, and of their tissue inhibitors (TIMP) was also measured. The results showed that exposure to high glucose (30 mM) increased the mRNA levels of both MMPs in OA chondrocytes, whereas in normal ones only MMP-1 increased. Collagen II mRNA was similarly increased in normal and OA chondrocytes, but the increase lasted longer in the later. Exposure to high glucose for 24 h prevented TGF-induced downregulation of MMP-13 gene expression in normal and OA chondrocytes, while the inhibitory effect of TGF on MMP-1 expression was only partially reduced. Other responses were not significantly modified. In conclusion, exposure of human chondrocytes to high glucose, as occurs in vivo in diabetes mellitus patients and in vitro for the production of engineered cartilage, favors the chondrocyte catabolic program. This may promote articular cartilage degradation, facilitating OA development and/or progression, as well as compromise the quality and consequent in vivo efficacy of tissue engineered cartilage

Evaluation of the anti-inflammatory, anti-catabolic and pro-anabolic effects of E-caryophyllene, myrcene and limonene in a cell model of osteoarthritis

Osteoarthritis is a progressive joint disease and a major cause of disability for which no curative therapies are yet available. To identify compounds with potential anti-osteoarthritic properties, in this study, we screened one sesquiterpene, E-caryophyllene, and two monoterpenes, myrcene and limonene, hydrocarbon compounds for anti-inflammatory, anti-catabolic and pro-anabolic activities in human chondrocytes. At non-cytotoxic concentrations, myrcene and limonene inhibited IL-1β-induced nitric oxide production (IC50=37.3μg/ml and 85.3µg/ml, respectively), but E-caryophyllene was inactive. Myrcene, and limonene to a lesser extent, also decreased IL-1β-induced NF-κB, JNK and p38 activation and the expression of inflammatory (iNOS) and catabolic (MMP-1 and MMP-13) genes, while increasing the expression of anti-catabolic genes (TIMP-1 and -3 by myrcene and TIMP-1 by limonene). Limonene increased ERK1/2 activation by 30%, while myrcene decreased it by 26%, relative to IL-1β-treated cells. None of the compounds tested was able to increase the expression of cartilage matrix-specific genes (collagen II and aggrecan), but both compounds prevented the increased expression of the non-cartilage specific, collagen I, induced by IL-1β. These data show that myrcene has significant anti-inflammatory and anti-catabolic effects in human chondrocytes and, thus, its ability to halt or, at least, slow down cartilage destruction and osteoarthritis progression warrants further investigation

Differential effects of the essential oils of Lavandula luisieri and Eryngium duriaei subsp. juresianum in cell models of two chronic inflammatory diseases

CONTEXT: Effective drugs to treat osteoarthritis (OA) and inflammatory bowel disease (IBD) are needed. OBJECTIVE: To identify essential oils (EOs) with anti-inflammatory activity in cell models of OA and IBD. MATERIALS AND METHODS: EOs from Eryngium duriaei subsp. juresianum (M. Laínz) M. Laínz (Apiaceae), Laserpitium eliasii subsp. thalictrifolium Sennen & Pau (Apiaceae), Lavandula luisieri (Rozeira) Rivas-Martínez (Lamiaceae), Othantus maritimus (L.) Hoff. & Link (Asteraceae), and Thapsia villosa L. (Apiaceae) were analyzed by GC and GC/MS. The anti-inflammatory activity of EOs (5-200 μg/mL) was evaluated by measuring inducible nitric oxide synthase (iNOS) and nuclear factor-κB (NF-κB) activation (total and phosphorylated IκB-α), in primary human chondrocytes and the intestinal cell line, C2BBe1, stimulated with interleukin-1β (IL-1β) or interferon-γ (IFN-γ), IL-1β and tumor necrosis factor-α (TNF-α), respectively. RESULTS: The EO of L. luisieri significantly reduced iNOS (by 54.9 and 81.0%, respectively) and phosphorylated IκB-α (by 87.4% and 62.3%, respectively) in both cell models. The EO of E. duriaei subsp. juresianum caused similar effects in human chondrocytes, but was inactive in intestinal cells, even at higher concentrations. The EOs of L. eliasii subsp. thalictrifolium and O. maritimus decreased iNOS expression by 45.2 ± 8.7% and 45.2 ± 6.2%, respectively, in C2BBe1 cells and were inactive in chondrocytes. The EO of T. villosa was inactive in both cell types. DISCUSSION AND CONCLUSION: This is the first study showing anti-inflammatory effects of the EOs of L. luisieri and E. duriaei subsp. juresianum. These effects are specific of the cell type and may be valuable to develop new therapies or as sources of active compounds with improved efficacy and selectivity towards OA and IBD

SRC inhibition prevents P-cadherin mediated signaling and function in basal-like breast cancer cells

BACKGROUND: Basal-like breast cancer (BLBC) is a poor prognosis subgroup of triple-negative carcinomas that still lack specific target therapies and accurate biomarkers for treatment selection. P-cadherin is frequently overexpressed in these tumors, promoting cell invasion, stem cell activity and tumorigenesis by the activation of Src-Family kinase (SRC) signaling. Therefore, our aim was to evaluate if the treatment of BLBC cells with dasatinib, the FDA approved SRC inhibitor, would impact on P-cadherin induced tumor aggressive behavior. METHODS: P-cadherin and SRC expression was evaluated in a series of invasive Breast Cancer and contingency tables and chi-square tests were performed. Cell-cell adhesion measurements were performed by Atomic Force Microscopy, where frequency histograms and Gaussian curves were applied. 2D and 3D cell migration and invasion, proteases secretion and self-renew potential were evaluated in vitro. Student's t-tests were used to determine statistically significant differences. The cadherin/catenin complex interactions were evaluated by in situ proximity-ligation assay, and statistically significant results were determined by using Mann-Whitney test with a Bonferroni correction. In vivo xenograft mouse models were used to evaluate the impact of dasatinib on tumor growth and survival. ANOVA test was used to evaluate the differences in tumor size, considering a confidence interval of 95%. Survival curves were estimated by the Kaplan-Meier's method, using the log-rank test to assess significant differences for mice overall survival. RESULTS: Our data demonstrated that P-cadherin overexpression is significantly associated with SRC activation in breast cancer cells, which was also validated in a large series of primary tumor samples. SRC activity suppression with dasatinib significantly prevented the in vitro functional effects of P-cadherin overexpressing cells, as well as their in vivo tumorigenic and metastatic ability, by increasing mice overall survival. Mechanistically, SRC inhibition affects P-cadherin downstream signaling, rescues the E-cadherin/p120-catenin complex to the cell membrane, recovering cell-cell adhesion function. CONCLUSIONS: In conclusion our findings show that targeting P-cadherin/SRC signaling and functional activity may open novel therapeutic opportunities for highly aggressive and poor prognostic basal-like breast cancer.This work was funded by Laço Grant 2014, by FEDER - Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 - Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by FCT - Fundação para a Ciência e a Tecnologia/ Ministério da Ciência, Tecnologia e Ensino Superior under the projects PTDC/SAU-GMG/120049/ 2010-FCOMP-01-0124-FEDER-021209, PEst-C/SAU/LA0003/2013, NORTE-01- 0145-FEDER-000029 and POCI-01-0145-FEDER-016390. FCT funded the research grants of ASR (SFRH/BPD/75705/2011), ARN (SFRH/BD/100380/2014), BS (SFRH/ BPD/104208/2014), AFV (SFRH/BPD/90303/2012), as well as JP with Programa IFCT 2013 (FCT Investigator). IPATIMUP integrates the i3S Research Unit, which is partially supported by FCT in the framework of the project “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274)

Hybridization in human evolution: Insights from other organisms

During the late Pleistocene, isolated lineages of hominins exchanged genes thus influencing genomic variation in humans in both the past and present. However, the dynamics of this genetic exchange and associated phenotypic consequences through time remain poorly understood. Gene exchange across divergent lineages can result in myriad outcomes arising from these dynamics and the environmental conditions under which it occurs. Here we draw from our collective research across various organisms, illustrating some of the ways in which gene exchange can structure genomic/phenotypic diversity within/among species. We present a range of examples relevant to questions about the evolution of hominins. These examples are not meant to be exhaustive, but rather illustrative of the diverse evolutionary causes/consequences of hybridization, highlighting potential drivers of human evolution in the context of hybridization including: influences on adaptive evolution, climate change, developmental systems, sex-differences in behavior, Haldane’s rule and the large X-effect, and transgressive phenotypic variation.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151330/1/evan21787.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151330/2/evan21787_am.pd

Numerical study of circulation on the inner Amazon Shelf

Author Posting. © Springer, 2008. 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 Ocean Dynamics 58 (2008): 187-198, doi:10.1007/s10236-008-0139-4.We studied the circulation on the coastal domain of the Amazon Shelf by applying the hydrodynamic module of the Estuarine and Coastal Ocean Model and Sediment Transport - ECOMSED. The first barotropic experiment aimed to explain the major bathymetric effects on tides and those generated by anisotropy in sediment distribution. We analyzed the continental shelf response of barotropic tides under realistic bottom stress parametrization (Cd), considering sediment granulometry obtained from a faciologic map, where river mud deposits and reworked sediments areas are well distinguished, among others classes of sediments. Very low Cd values were set in the fluid mud regions off the Amapa coast (1.0 10-4 ), in contrast to values around 3:5 10-3 for coarser sediment regions off the Para coast. Three-dimensional experiments represented the Amazon River discharge and trade winds, combined to barotropic tide influences and induced vertical mixing. The quasi-resonant response of the Amazon Shelf to the M2 tide act on the local hydrodynamics by increasing tidal admittance, along with tidal forcing at the shelf break and extensive fluid mud regions. Harmonic analysis of modeled currents agreed well with analysis of the AMASSEDS observational data set. Tidal-induced vertical shear provided strong homogenization of threshold waters, which are subject to a kind of hydraulic control due to the topographic steepness. Ahead of the hydraulic jump, the low-salinity plume is disconnected from the bottom and acquires negative vorticity, turning southeastward. Tides act as a generator mechanism and topography, via hydraulic control, as a maintainer mechanism for the low-salinity frontal zone positioning. Tidally induced southeastward plume fate is overwhelmed by northwestward trade winds so that, along with background circulation, probably play the most important role on the plume fate and variability over the Amazon Shelf