Combining nerve and tendon transfers in tetraplegia: a proposal of a new surgical strategy based on literature review.

Spinal cord injury (SCI) is very common, most frequently resulting from motor vehicle accidents and falling from a height. Often, SCI occurs at the cervical level, resulting in tetraplegia, which consists of loss of effective arm and/or hand function. For these patients, hand function is considered the most desired function, above bowel, bladder and sexual function. Fortunately, understanding about nerve and tendon transfers is steadily growing, providing new surgical solutions for functional restoration in tetraplegia patients. The primary aim of this systematic review of the literature is to assess all the various ways to improve upper-limb function, using both nerve transfers and classical tendon transfers in patients suffering from tetraplegia. Surgical indications, optimum timing and contraindications were reviewed. In accordance with the International Classification for Surgery of the Hand in Tetraplegia, ten subgroups of tetraplegic patients were analysed and a proposal for treatment combining nerve and tendon transfers formulated for each subgroup, seeking alternatives to classical surgical strategies. We also sought to propose strategies that, in instances of failure, still would allow for the use of some classical surgical approach. Starting with traditional management, we proposed new strategies using tenodesis and tendon transfers in association with nerve surgery. We believe that the suggestions described in the current paper could both improve and complete current surgical strategies and contribute to ensuring that more patients benefit from these options in future.

In Vitro Co-Culture Models of Breast Cancer Metastatic Progression towards Bone.

Advanced breast cancer frequently metastasizes to bone through a multistep process involving the detachment of cells from the primary tumor, their intravasation into the bloodstream, adhesion to the endothelium and extravasation into the bone, culminating with the establishment of a vicious cycle causing extensive bone lysis. In recent years, the crosstalk between tumor cells and secondary organs microenvironment is gaining much attention, being indicated as a crucial aspect in all metastatic steps. To investigate the complex interrelation between the tumor and the microenvironment, both in vitro and in vivo models have been exploited. In vitro models have some advantages over in vivo, mainly the possibility to thoroughly dissect in controlled conditions and with only human cells the cellular and molecular mechanisms underlying the metastatic progression. In this article we will review the main results deriving from in vitro co-culture models, describing mechanisms activated in the crosstalk between breast cancer and bone cells which drive the different metastatic steps.

Direct but not indirect co-culture with osteogenically differentiated human bone marrow stromal cells increases RANKL/OPG ratio in human breast cancer cells generating bone metastases.

BACKGROUND: Bone metastases arise in nearly 70% of patients with advanced breast cancer, but the complex metastatic process has not been completely clarified yet. RANKL/RANK/OPG pathway modifications and the crosstalk between metastatic cells and bone have been indicated as potential drivers of the process. Interactions between tumor and bone cells have been studied in vivo and in vitro, but specific effects of the direct contact between human metastatic cells and human bone cells on RANKL/RANK/OPG pathway have not been investigated. FINDINGS: We directly co-cultured bone metastatic human breast cancer cells (BOKL) with osteo-differentiated human mesenchymal cells (BMSCs) from 3 different donors. BMSCs and BOKL were then enzymatically separated and FACS sorted. We found a significant increase in the RANKL/OPG ratio as compared to control, which was not observed in BOKL cultured in medium conditioned by BMSCs, neither in BOKL directly cultured with fibroblasts or medium conditioned by fibroblasts. Direct co-culture with osteo-differentiated BMSCs caused BOKL aggregation while proliferation was not affected by co-culture. To more specifically associate RANKL expression to osteogenic differentiation degree of BMSCs, we determined their osteogenic markers expression and matrix calcification relative to osteoblasts and fibroblasts. CONCLUSIONS: In conclusion, our co-culture model allowed to demonstrate for the first time that direct contact but not paracrine interactions between human metastatic breast cancer cells and bone cells has a significant effect on RANKL/OPG expression in bone metastatic cells. Furthermore, only direct contact with the bone microenvironment induced BOKL clustering without however significantly influencing their proliferation and migration.

Characterization of articular chondrocytes isolated from 211 osteoarthritic patients.

We analyzed specific features of chondrocytes as cellular yield, cell doubling rates and the dependence between these parameters and patient-related data in a set of 211 osteoarthritic (OA) patients undergoing total joint replacement. For each patient the data available were joint type, age and gender. Knee samples chosen randomly among all biopsies were graded according to ICRS score. Patients' age ranged between 30 and 90 years with a mean age of 66 ± 9.7 years. Patients were divided into age classes and statistically significant differences in proliferation rate at passage 1 were found between chondrocytes derived from young and old donors, with the last ones characterized by a lower proliferation rate. A similar trend was observed for proliferation rate at passage 2. For all the samples, cellular yields ranged between 0.1 and 5.5 million cells/g of tissue. No significant correlation was observed between the level of cartilage degeneration (ICRS score) and cellular yield and proliferation rates. However, in samples with a high degree of cartilage degeneration (ICRS score 4) the cellular yield was lower compared to the other three groups (ICRS scores 1-3). In this study we performed a systematic characterization of basic parameters of chondrocytes originating from a wide group of OA patients. Considering the use of autologous chondrocytes in chondral treatments, the characterization of cell basic features may represent an important step to determine the quality of the cell source which is a major determinant in the outcome of cell-based therapies.

Complex or not too complex? One size does not fit all in next generation microphysiological systems.

In the attempt to overcome the increasingly recognized shortcomings of existing in vitro and in vivo models, researchers have started to implement alternative models, including microphysiological systems. First examples were represented by 2.5D systems, such as microfluidic channels covered by cell monolayers as blood vessel replicates. In recent years, increasingly complex microphysiological systems have been developed, up to multi-organ on chip systems, connecting different 3D tissues in the same device. However, such an increase in model complexity raises several questions about their exploitation and implementation into industrial and clinical applications, ranging from how to improve their reproducibility, robustness, and reliability to how to meaningfully and efficiently analyze the huge amount of heterogeneous datasets emerging from these devices. Considering the multitude of envisaged applications for microphysiological systems, it appears now necessary to tailor their complexity on the intended purpose, being academic or industrial, and possibly combine results deriving from differently complex stages to increase their predictive power.

Implants removal in children: results of a survey among Italian orthopaedic surgeons.

In the treatment of paediatric limb disorders, the use of metal implants has been increasing over the last decades. Recent studies have addressed the decision of orthopaedic surgeons regarding the removal of implants after the treatment of fracture, and there is a growing consensus within the scientific community supporting the choice of not removing implants in children. This survey aimed to investigate the rationale behind the Italian orthopaedic community's decision regarding metal implant removal in paediatric patients. An electronic questionnaire was sent to all members of the Italian Paediatric Orthopaedic and Traumatology Society, Italian Orthopaedic and Traumatology Society, Italian Club of Osteosynthesis, and South Italy Society of Orthopaedic and Traumatology. The survey comprised 34 questions about hardware removal after the treatment of long bone fractures, epiphyseal growth plate injuries, slipped capital femoral epiphysis (SCFE), and flat foot. Of the 3500 orthopaedic surgeons who received the questionnaire, 5.5% responded. The leading indications for implant removal were the patient's intolerance, pain, ROM limitations, and hardware breakage. Removal of elastic nails for long bone fractures, cannulated screws for growth plate injuries, and SCFE and screws for arthroereisis for flat foot correction were analysed in detail. The consensus among Italian Orthopaedic Surgeons is to remove elastic nails and cannulated screws in cases of pain, intolerance, or breakage and to reduce further risks during patient growth. An increasing number of physicians, however, are endorsing and advocating the growing trend in the literature of not routinely removing the hardware.

A personalized osteoarthritic joint-on-a-chip as a screening platform for biological treatments.

Osteoarthritis (OA) is a highly disabling pathology, characterized by synovial inflammation and cartilage degeneration. Orthobiologics have shown promising results in OA treatment thanks to their ability to influence articular cells and modulate the inflammatory OA environment. Considering their complex mechanism of action, the development of reliable and relevant joint models appears as crucial to select the best orthobiologics for each patient. The aim of this study was to establish a microfluidic OA model to test therapies in a personalized human setting. The joint-on-a-chip model included cartilage and synovial compartments, containing hydrogel-embedded chondrocytes and synovial fibroblasts, separated by a channel for synovial fluid. For the cartilage compartment, a Hyaluronic Acid-based matrix was selected to preserve chondrocyte phenotype. Adding OA synovial fluid induced the production of inflammatory cytokines and degradative enzymes, generating an OA microenvironment. Personalized models were generated using patient-matched cells and synovial fluid to test the efficacy of mesenchymal stem cells on OA signatures. The patient-specific models allowed monitoring changes induced by cell injection, highlighting different individual responses to the treatment. Altogether, these results support the use of this joint-on-a-chip model as a prognostic tool to screen the patient-specific efficacy of orthobiologics.

Phasor-FLIM-guided unraveling of ATRA supramolecular organization in liposomal nanoformulations.

Here we use fluorescence lifetime imaging microscopy (FLIM) to study the supramolecular organization of nanoencapsulated liposomal all-trans retinoic acid (ATRA), exploiting ATRA's intrinsic fluorescence as a source of signal and phasor transformation as a fit-free analytical approach to lifetime data. Our non-invasive method is suitable for checking for the presence of a fraction of ATRA molecules interacting with liposomal membranes. The results are validated by independent small-angle X-ray scattering (SAXS) and nano-differential scanning calorimetry (NanoDSC) measurements, probing ATRA's putative position on the membrane and effect on membrane organization. Besides the insights on the specific case-study proposed, the present results confirm the effectiveness of Phasor-FLIM analysis in elucidating the nanoscale supramolecular organization of fluorescent drugs in pharmaceutical formulations. This underscores the importance of leveraging advanced imaging techniques to deepen our understanding and optimize drugs' performance in delivery applications.

Differential angiogenesis of bone and muscle endothelium in aging and inflammatory processes.

Different tissues have different endothelial features, however, the implications of this heterogeneity in pathological responses are not clear yet. "Inflamm-aging" has been hypothesized as a possible trigger of diseases, including osteoarthritis (OA) and sarcopenia, often present in the same patient. To highlight a possible contribution of organ-specific endothelial cells (ECs), we compare ECs derived from bone and skeletal muscle of the same OA patients. OA bone ECs show a pro-inflammatory signature and higher angiogenic sprouting as compared to muscle ECs, in control conditions and stimulated with TNFα. Furthermore, growth of muscle but not bone ECs decreases with increasing patient age and systemic inflammation. Overall, our data demonstrate that inflammatory conditions in OA patients differently affect bone and muscle ECs, suggesting that inflammatory processes increase angiogenesis in subchondral bone while associated systemic low-grade inflammation impairs angiogenesis in muscle, possibly highlighting a vascular trigger linking OA and sarcopenia.

Chronic Monteggia in pediatric population: A narrative literature review.

Monteggia lesion is a traumatic condition that affects the forearm and is characterized by the association of an ulna fracture with a dislocation of the radius capitellar and proximal radius ulnar joints in the majority of cases. Although several authors have contributed to the understanding of this pathology over the years, it remains a challenge for orthopedists, and if not recognized and treated properly, it can have serious consequences. In these cases, a chronic injury develops, which is even more difficult to manage in terms of timing and treatment options. A narrative review of the literature on missed elbow injuries in children was conducted, and chronic Monteggia was the most frequently encountered injury. The analysis of the articles attempts to clarify some points and draw general conclusions on which to reflect.

3D Biofabricated In Vitro Models of Vascularized and Mineralized Bone Tissues.

This protocol describes a comprehensive practical guide for the biofabrication of 3D in vitro models of vascularized and mineralized bone Minitissues. These models give the possibility to study the contribution of physical and biochemical parameters on bone vascularization, as well as the osteoblast/osteoclast mediated matrix remodeling. Based on the specific pathophysiological processes to be investigated, the 3D bone Minitissues allow to select the most suitable cell composition, by coculturing up to four cell types, and to customize the material properties of the hydrogel matrix. Considering their versatility, these 3D bone Minitissues could be relevant for the recapitulation of bone pathologies such as bone tumors and metastases and could be and used as screening platforms to test antimetastatic drugs.

Use of a 3D Model for the Correction of a Complex Madelung Deformity in a Teenager: A Case Report.

CASE: The aim of the article is to report on a case of a teenager affected by Madelung deformity treated with a double osteotomy, planned by means of a 3D model. Using a custom-made cutting guide, the radial osteotomy was performed, and after the reorientation, a shortening ulnar osteotomy completed the procedure. Postoperative clinical assessment showed a normal alignment of the ulna with increased range of motion wrist motion. CONCLUSIONS: Using a 3D model when planning a multidirectional correction of a Madelung deformity may be advantageous to achieve a more accurate and precise realignment of the carpus and distal radioulnar joint.

A microfluidic model of human vascularized breast cancer metastasis to bone for the study of neutrophil-cancer cell interactions.

The organ-specific metastatization of breast cancer to bone is driven by specific interactions between the host microenvironment and cancer cells (CCs). However, it is still unclear the role that circulating immune cells, including neutrophils, play during bone colonization (i.e. pro-tumoral vs. anti-tumoral). Here, we aimed at analyzing the migratory behavior of neutrophils when exposed to breast CCs colonizing the bone and their contribution to the growth of breast cancer micrometastases. Based on our previous bone metastasis models, we designed a microfluidic system that allows to independently introduce human vascularized breast cancer metastatic seeds within a bone-mimicking microenvironment containing osteo-differentiated mesenchymal stromal cells and endothelial cells (ECs). ECs self-assembled into microvascular networks and connected the bone-mimicking microenvironment with the metastatic seed. Compared to controls without CCs, metastatic seeds compromised the architecture of microvascular networks resulting in a lower number of junctions (5.7 â€‹± â€‹1.2 vs. 18.8 â€‹± â€‹4.5, p â€‹= â€‹0.025) and shorter network length (10.5 â€‹± â€‹1.0 vs. 13.4 â€‹± â€‹0.8 [mm], p â€‹= â€‹0.042). Further, vascular permeability was significantly higher with CCs (2.60 â€‹× â€‹10-8 â€‹± â€‹3.59 â€‹× â€‹10-8 â€‹vs. 0.53 â€‹× â€‹10-8 â€‹± â€‹0.44 â€‹× â€‹10-8 [cm/s], p â€‹= â€‹0.05). Following metastatic seed maturation, neutrophils were injected into microvascular networks resulting in a higher extravasation rate when CCs were present (27.9 â€‹± â€‹13.7 vs. 14.7 â€‹± â€‹12.4 [%], p â€‹= â€‹0.01). Strikingly, the percentage of dying CCs increased in presence of neutrophils, as confirmed by confocal imaging and flow cytometry on isolated cells from the metastatic seeds. The biofabricated metastatic niche represents a powerful tool to analyze the mechanisms of interaction between circulating immune cells and organ-specific micrometastases and to test novel drug combinations targeting the metastatic microenvironment.

Correction: A microphysiological early metastatic niche on a chip reveals how heterotypic cell interactions and inhibition of integrin subunit ß3 impact breast cancer cell extravasation.

Correction for 'A microphysiological early metastatic niche on a chip reveals how heterotypic cell interactions and inhibition of integrin subunit ß3 impact breast cancer cell extravasation' by Martina Crippa et al., Lab Chip, 2021, DOI: .

A microphysiological early metastatic niche on a chip reveals how heterotypic cell interactions and inhibition of integrin subunit ß3 impact breast cancer cell extravasation.

During metastatic progression multiple players establish competitive mechanisms, whereby cancer cells (CCs) are exposed to both pro- and anti-metastatic stimuli. The early metastatic niche (EMN) is a transient microenvironment which forms in the circulation during CC dissemination. EMN is characterized by the crosstalk among CCs, platelets, leukocytes and endothelial cells (ECs), increasing CC ability to extravasate and colonize secondary tissues. To better understand this complex crosstalk, we designed a human "EMN-on-a-chip" which involves the presence of blood cells as compared to standard metastases-on-chip models, hence providing a microenvironment more similar to the in vivo situation. We showed that CC transendothelial migration (TEM) was significantly increased in the presence of neutrophils and platelets in the EMN-on-a-chip compared to CC alone. Moreover, exploiting the EMN-on-chip in combination with multi-culture experiments, we showed that platelets increased the expression of epithelial to mesenchymal transition (EMT) markers in CCs and that the addition of a clinically approved antiplatelet drug (eptifibatide, inhibiting integrin ß3) impaired platelet aggregation and decreased CC expression of EMT markers. Inhibition of integrin ß3 in the co-culture system modulated the activation of the Src-FAK-VE-cadherin signaling axis and partially restored the architecture of inter-endothelial junctions by limiting VE-cadherinY658 phosphorylation and its nuclear localization. These observations correlate with the decreased CC TEM observed in the presence of integrin ß3 inhibitor. Our EMN-on-a-chip can be easily implemented for drug repurposing studies and to investigate new candidate molecules counteracting CC extravasation.

Improving cell seeding efficiency through modification of fiber geometry in 3D printed scaffolds.

Cell seeding on 3D scaffolds is a very delicate step in tissue engineering applications, influencing the outcome of the subsequent culture phase, and determining the results of the entire experiment. Thus, it is crucial to maximize its efficiency. To this purpose, a detailed study of the influence of the geometry of the scaffold fibers on dynamic seeding efficiency is presented. 3D printing technology was used to realize polylactic acid porous scaffolds, formed by fibers with a non-circular cross-sectional geometry, named multilobed to highlight the presence of niches and ridges. An oscillating perfusion bioreactor was used to perform bidirectional dynamic seeding of MG63 cells. The fiber shape influences the fluid dynamic parameters of the flow, affecting values of fluid velocity and wall shear stress. The path followed by cells through the scaffold fibers is also affected and results in a larger number of adhered cells in multilobed scaffolds compared to scaffolds with standard pseudo cylindrical fibers. Geometrical and fluid dynamic features can also have an influence on the morphology of adhered cells. The obtained results suggest that the reciprocal influence of geometrical and fluid dynamic features and their combined effect on cell trajectories should be considered to improve the dynamic seeding efficiency when designing scaffold architecture.

Engineering the early bone metastatic niche through human vascularized immuno bone minitissues.

Bone metastases occur in 65%-80% advanced breast cancer patients. Although significant progresses have been made in understanding the biological mechanisms driving the bone metastatic cascade, traditional 2Din vitromodels and animal studies are not effectively reproducing breast cancer cells (CCs) interactions with the bone microenvironment and suffer from species-specific differences, respectively. Moreover, simplifiedin vitromodels cannot realistically estimate drug anti-tumoral properties and side effects, hence leading to pre-clinical testing frequent failures. To solve this issue, a 3D metastatic bone minitissue (MBm) is designed with embedded human osteoblasts, osteoclasts, bone-resident macrophages, endothelial cells and breast CCs. This minitissue recapitulates key features of the bone metastatic niche, including the alteration of macrophage polarization and microvascular architecture, along with the induction of CC micrometastases and osteomimicry. The minitissue reflects breast CC organ-specific metastatization to bone compared to a muscle minitissue. Finally, two FDA approved drugs, doxorubicin and rapamycin, have been tested showing that the dose required to impair CC growth is significantly higher in the MBm compared to a simpler CC monoculture minitissue. The MBm allows the investigation of metastasis key biological features and represents a reliable tool to better predict drug effects on the metastatic bone microenvironment.

Radiobiological Studies of Microvascular Damage through In Vitro Models: A Methodological Perspective.

Ionizing radiation (IR) is used in radiotherapy as a treatment to destroy cancer. Such treatment also affects other tissues, resulting in the so-called normal tissue complications. Endothelial cells (ECs) composing the microvasculature have essential roles in the microenvironment's homeostasis (ME). Thus, detrimental effects induced by irradiation on ECs can influence both the tumor and healthy tissue. In-vitro models can be advantageous to study these phenomena. In this systematic review, we analyzed in-vitro models of ECs subjected to IR. We highlighted the critical issues involved in the production, irradiation, and analysis of such radiobiological in-vitro models to study microvascular endothelial cells damage. For each step, we analyzed common methodologies and critical points required to obtain a reliable model. We identified the generation of a 3D environment for model production and the inclusion of heterogeneous cell populations for a reliable ME recapitulation. Additionally, we highlighted how essential information on the irradiation scheme, crucial to correlate better observed in vitro effects to the clinical scenario, are often neglected in the analyzed studies, limiting the translation of achieved results.

Organs-on-a-chip as model systems for multifactorial musculoskeletal diseases.

Multifactorial diseases affecting musculoskeletal tissues are characterized by the interactions between multiple tissues, such as muscle and nerves in neuromuscular diseases, or multiple cellular components in a tissue, as in the case of bone tumors, interacting with bone cells. For these diseases also the influence of different biophysical and biochemical stimuli, such as mechanical overload and inflammatory molecules in osteoarthritis, play a key role. To investigate these complex phenomena, organ-on-a-chip systems have been developed, taking into account specific disease characteristics such as being directly derived from patients, the presence of specifically mutated cells, or a combination of relevant biophysical and/or biochemical stimuli. Depending on the envisaged application, different issues remain to be addressed. In particular, improving automation and output sensors are key for drug screening applications, while refining model microarchitecture to enhance physiological fidelity is needed for more basic science studies.