Reconstruction Of Blood Vessels Research Articles

Amino Acid Functionalized SrTiO3 Nanoarrays with Enhanced Osseointegration Through Programmed Rapid Biofilm Elimination and Angiogenesis Controlled by NIR-Driven Gas Therapy.

Bacterial biofilm formation is closely associated with persistent infections of medical implants, which can lead to implantation failure. Additionally, the reconstruction of the vascular network is crucial for achieving efficient osseointegration. Herein, an anti-biofilm nanoplatform based on L-arginine (LA)/new indocyanine green (NICG) that is anchored to strontim titanium oxide (SrTiO3) nano-arrays on a titanium (Ti) substrate by introducing polydopamine (PDA) serving as the interlayer is designed and successfully fabricated. Near-infrared light (NIR) is used to excite NICG, generating reactive oxygen species (ROS) that react with LA to release nitric oxide (NO) molecules. Utilizing the concentration-dependent effect of NO, high power density NIR irradiation applied during the early stage after implantation to release a high concentration of NO, which synergized with the photothermal effect of PDA to eliminate bacterial biofilm. Subsequently, the irradiation power density can be finely down-regulated to reduce the NO concentration in subsequent treatment for accelerating the reconstruction of blood vessels. Meanwhile, SrTiO3 nano-arrays improve the hydrophilicity of the implant surface and slowly release strontium (Sr) ions for continuously optimizing the osteogenic microenvironment. Effective biofilm elimination and revascularization alongside the continuous optimization of the osteogenic microenvironment can significantly enhance the osseointegration of the functionalized Ti implant in in vivo animal experiments.

A Recombinant Lentiviral Vegfr2-Silencing Vector Attenuates Roxarsone-Promoted Growth of Rat Vascular Endothelial Cells and Angiogenesis in Matrigel Plug and B16F10 Xenograft Models.

Roxarsone (ROX) is widely used as a feed addictive for livestock and poultry. ROX promotes angiogenesis, which can lead to health problems, and it is necessary to identify methods to counter this angiogenic effect of ROX. The VEGF/VEGFR2 signaling pathway is involved in the growth and reconstruction of new blood vessels during angiogenesis. In this study, a recombinant lentiviral vector encoding Vegfr2 shRNA was transfected into rat vascular endothelial cells and used in mouse matrigel plug and melanoma xenograft models to investigate its potential to regulate ROX-induced angiogenesis and tumor growth. Treating endothelial cells with ROX increased cell proliferation, migration, and a tube-like structure of growth relative to the control group. The addition of the lentiviral Vegfr2-silencing vector significantly attenuated the effects of ROX on endothelial cells. The hemoglobin content of mouse matrigel plugs treated with ROX was increased significantly. This effect was dramatically attenuated by the co-administration of shRNA targeting Vegfr2. The volume, weight and CD34 staining of the melanoma xenograft tumors increased by ROX were also attenuated by Vegfr2 silence. These results indicate that the down-regulation of VEGFR2 protein plays an inhibitory role in the ROX-promoted angiogenesis in vivo and in vitro. These data support the targeting of Vegfr2 gene as an effective means to treat ROX-induced angiogenesis and tumor growth.

A semiparametric Gaussian mixture model for chest CT-based 3D blood vessel reconstruction.

Computed tomography (CT) has been a powerful diagnostic tool since its emergence in the 1970s. Using CT data, 3D structures of human internal organs and tissues, such as blood vessels, can be reconstructed using professional software. This 3D reconstruction is crucial for surgical operations and can serve as a vivid medical teaching example. However, traditional 3D reconstruction heavily relies on manual operations, which are time-consuming, subjective, and require substantial experience. To address this problem, we develop a novel semiparametric Gaussian mixture model tailored for the 3D reconstruction of blood vessels. This model extends the classical Gaussian mixture model by enabling nonparametric variations in the component-wise parameters of interest according to voxel positions. We develop a kernel-based expectation-maximization algorithm for estimating the model parameters, accompanied by a supporting asymptotic theory. Furthermore, we propose a novel regression method for optimal bandwidth selection. Compared to the conventional cross-validation-based (CV) method, the regression method outperforms the CV method in terms of computational and statistical efficiency. In application, this methodology facilitates the fully automated reconstruction of 3D blood vessel structures with remarkable accuracy.

Retinal vessel volume reference database derived from volume-rendered optical coherence tomography angiography

Optical coherence tomography angiography (OCTA) enables three-dimensional reconstruction of the functional blood vessels in the retina. Therefore, it enables the quantification of 3D retinal vessel parameters such as surface area and vessel volume. In spite of the widespread use of OCTA, no representative volume-rendered vessel volume (VV) data are published to date. In this study, OCTA 3 × 3 mm macular cubes were processed with volume-rendering techniques to measure VV in 203 eyes from 107 healthy volunteers. Generalized linear models (GLM) were constructed to assess the impact of age, gender, visual acuity (VA), spherical equivalent (SE), and axial length (AL) on VV. Overall mean VV was 0.23 ± 0.05mm3. Age and axial length showed a negative correlation with VV. However, GLM model analysis found that AL exerted the most pronounced influence on VV. No statistically significant associations were identified between gender or between left and right eyes. This is the first study to assess 3D OCTA VV and its naturally occurring variations in a large series of healthy subjects. It offers novel insights into the characterization of normal retinal vascular anatomy in healthy individuals, contributing to a valuable reference for future research in this field.

Study on high-precision three-dimensional reconstruction of pulmonary lesions and surrounding blood vessels based on CT images.

The adoption of computerized tomography (CT) technology has significantly elevated the role of pulmonary CT imaging in diagnosing and treating pulmonary diseases. However, challenges persist due to the complex relationship between lesions within pulmonary tissue and the surrounding blood vessels. These challenges involve achieving precise three-dimensional reconstruction while maintaining accurate relative positioning of these elements. To effectively address this issue, this study employs a semi-automatic precise labeling process for the target region. This procedure ensures a high level of consistency in the relative positions of lesions and the surrounding blood vessels. Additionally, a morphological gradient interpolation algorithm, combined with Gaussian filtering, is applied to facilitate high-precision three-dimensional reconstruction of both lesions and blood vessels. Furthermore, this technique enables post-reconstruction slicing at any layer, facilitating intuitive exploration of the correlation between blood vessels and lesion layers. Moreover, the study utilizes physiological knowledge to simulate real-world blood vessel intersections, determining the range of blood vessel branch angles and achieving seamless continuity at internal blood vessel branch points. The experimental results achieved a satisfactory reconstruction with an average Hausdorff distance of 1.5 mm and an average Dice coefficient of 92%, obtained by comparing the reconstructed shape with the original shape,the approach also achieves a high level of accuracy in three-dimensional reconstruction and visualization. In conclusion, this study is a valuable source of technical support for the diagnosis and treatment of pulmonary diseases and holds promising potential for widespread adoption in clinical practice.

Transmetacarpal replantation

Introduction. Transmetacarpal amputation (TA) distal to the superficial palmar arch is one of the most difficult procedures in replantation surgery because it requires the reconstruction of blood vessels, muscles, tendons, bones, nerves, and skin. We present a case of a patient with TA of the left hand and microsurgical replantation. Case report. A 23-year-old left-hand dominant male worker with a positive smoking history sustained TA from a radial saw blade and avulsion injury of the palmar side of the thumb with no other apparent injuries. The time between the amputation and replantation was 4 hrs. The patient sustained the amputation at the level of metacar-pophalangeal joints. The successful replantation included: wound and intrinsic muscles debridement, microvascular anastomoses of the blood vessels, internal fixation of the metacarpal bones, neurorrhaphy, tenorrhaphy, and wound closure with local skin flap for thumb soft tissue defect. The patient was followed for seven years postoperatively. Conclusion. The replantation surgery requires a specialized department and well-educated teams of hand microsurgeons, orthopedic surgeons, and anesthesiologists. The most imortant factors that influenced the outcome after the replantation in the presented case included the type and level of injury, ischemia time, comorbidities, age, smoking history, and physical therapy.

Brain MRA 3D Skeleton Extraction Based on Normal Plane Centroid Algorithm

INTRODUCTION: Analysis of magnetic resonance angiography image data is crucial for early detection and prevention of stroke patients. Extracting the 3D Skeleton of cerebral vessels is the focus and difficulty of analysis.
 OBJECTIVES: The objective is to remove other tissue components from the vascular tissue portion of the image with minimal loss by reading MRA image data and performing processing processes such as grayscale normalization, interpolation, breakpoint detection and repair, and image segmentation to facilitate 3D reconstruction of cerebral blood vessels and the reconstructed vascular tissues make extraction of the Skeleton easier.
 METHODS: Considering that most of the existing techniques for extracting the 3D vascular Skeleton are corrosion algorithms, machine learning algorithms require high hardware resources, a large number of learning and test cases, and the accuracy needs to be confirmed, an average plane center of mass computation method is proposed, which improves the average plane algorithm by combining the standard plane algorithm and the center of mass algorithm.
 RESULTS: Intersection points and skeleton breakpoints on the Skeleton are selected as critical points and manually labeled for experimental verification, and the algorithm has higher efficiency and accuracy than other algorithms in directly extracting the 3D Skeleton of blood vessels.
 CONCLUSION: The method has low hardware requirements, accurate and reliable image data, can be automatically modeled and calculated by Python program, and meets the needs of clinical applications under information technology conditions.

Dual siRNA-Loaded Cell Membrane Functionalized Matrix Facilitates Bone Regeneration with Angiogenesis and Neurogenesis.

Vascularization and innervation play irreplaceable roles in bone regeneration and bone defect repair. However, the reconstruction of blood vessels and neural networks is often neglected in material design. This study aims to design a genetically functionalized matrix (GFM) and enable it to regulate angiogenesis and neurogenesis to accelerate the process of bone defect repair. The dual small interfering RNA (siRNA)-polyvinylimide (PEI)(siRP) complexes that locally knocked down soluble vascular endothelial growth factor receptor 1 (sFlt-1) and p75 neurotrophic factor receptor (p75NTR ) are prepared. The hybrid cell membrane (MM) loaded siRP is synthesized as siRNA@MMs to coat on polylactone (PCL) electrospun fibers for mimicking the natural bone matrix. The results indicates that siRNA@MMs could regulate the expression of vascular-related and neuro-related cytokines secreted by mesenchymal stem cells (MSCs). GFMs promote the expression of osteogenic differentiation through paracrine function in vitro. GFMs attenuates inflammation and promotes osseointegration by regulating the coupling of vascularization and innervation in vivo. This study uses the natural hybrid cell membrane to carry genetic material and assist in the vascularization and innervation function of two siRNA. The results present the significance of neuro-vascularized organoid bone and may provide a promising choice for the design of bone tissue engineering scaffold.

Reconstruction and Validation of Arterial Geometries for Computational Fluid Dynamics Using Multiple Temporal Frames of 4D Flow-MRI Magnitude Images

PurposeSegmentation and reconstruction of arterial blood vessels is a fundamental step in the translation of computational fluid dynamics (CFD) to the clinical practice. Four-dimensional flow magnetic resonance imaging (4D Flow-MRI) can provide detailed information of blood flow but processing this information to elucidate the underlying anatomical structures is challenging. In this study, we present a novel approach to create high-contrast anatomical images from retrospective 4D Flow-MRI data.MethodsFor healthy and clinical cases, the 3D instantaneous velocities at multiple cardiac time steps were superimposed directly onto the 4D Flow-MRI magnitude images and combined into a single composite frame. This new Composite Phase-Contrast Magnetic Resonance Angiogram (CPC-MRA) resulted in enhanced and uniform contrast within the lumen. These images were subsequently segmented and reconstructed to generate 3D arterial models for CFD. Using the time-dependent, 3D incompressible Reynolds-averaged Navier–Stokes equations, the transient aortic haemodynamics was computed within a rigid wall model of patient geometries.ResultsValidation of these models against the gold standard CT-based approach showed no statistically significant inter-modality difference regarding vessel radius or curvature (p > 0.05), and a similar Dice Similarity Coefficient and Hausdorff Distance. CFD-derived near-wall hemodynamics indicated a significant inter-modality difference (p > 0.05), though these absolute errors were small. When compared to the in vivo data, CFD-derived velocities were qualitatively similar.ConclusionThis proof-of-concept study demonstrated that functional 4D Flow-MRI information can be utilized to retrospectively generate anatomical information for CFD models in the absence of standard imaging datasets and intravenous contrast.

Biomimetic Liquid Crystal-Modified Mesoporous Silica−Based Composite Hydrogel for Soft Tissue Repair

The reconstruction of blood vessels plays a critical role in the tissue regeneration process. However, existing wound dressings in tissue engineering face challenges due to inadequate revascularization induction and a lack of vascular structure. In this study, we report the modification of mesoporous silica nanospheres (MSNs) with liquid crystal (LC) to enhance bioactivity and biocompatibility in vitro. This LC modification facilitated crucial cellular processes such as the proliferation, migration, spreading, and expression of angiogenesis−related genes and proteins in human umbilical vein endothelial cells (HUVECs). Furthermore, we incorporated LC−modified MSN within a hydrogel matrix to create a multifunctional dressing that combines the biological benefits of LC−MSN with the mechanical advantages of a hydrogel. Upon application to full−thickness wounds, these composite hydrogels exhibited accelerated healing, evidenced by enhanced granulation tissue formation, increased collagen deposition, and improved vascular development. Our findings suggest that the LC−MSN hydrogel formulation holds significant promise for the repair and regeneration of soft tissues.

“Call Vascular”: Vascular Surgery an Indispensable Service in a Highly Functional Complex Hospital System

With the maturation of vascular surgery as an independent specialty, vascular surgeons have become an essential resource in any hospital system. Not only do vascular surgeons provide the breadth of open and endovascular treatment to patients with vascular disease, but they are also an important resource for other surgical subspecialties, providing open exposure, control of life-threatening hemorrhage, repair and reconstruction of blood vessels, using both open and endovascular techniques. We conducted a retrospective review of the concurrent intraoperative involvement of vascular surgery with another surgical service at tertiary care, level 1 trauma designated academic medical center over a ten-year period in which vascular surgery was consulted to assist another surgical service. The consults were classified as intraoperative, emergent in which vascular surgery was consulted prior to surgery either in the emergency department or in the hospital and electively scheduled procedures. We identified 362 cases in which vascular surgery was consulted for operative assistance by another surgical service from August 2012 to May 2022. This equates to approximately three consults per month. The majority (57%) were trauma cases. Of the nontrauma-related cases, 33% were intraoperative consults, 35% emergent, and 32% were electively scheduled procedures. Of the trauma cases, 50% were intraoperative consults and 50% emergent consults (Table I). The most common reason for a vascular surgery consult on a trauma patient was limb ischemia (65%), followed by assistance with uncontrolled hemorrhage (25%). The most common reason for a vascular surgery consult on a nontrauma patient was for assistance with exposure (52%) followed by uncontrolled hemorrhage (21%) (Table II). The specialties requiring vascular assistance included trauma surgery, general surgery, urology, orthopedic surgery, plastic surgery, obstetrics/gynecology, neurosurgery, cardiothoracic surgery, transplant surgery, surgical oncology, orthopedic oncology, pediatric surgery, ENT, and cardiology. Vascular surgery provides operative support to and collaboration with every other surgical specialty. In the majority of cases, vascular surgery is consulted either intraoperatively or emergently. In addition to providing care to patients with vascular disease, vascular surgeons assist other specialists in providing care to their patients. Vascular surgeons are a crucial resource for a hospital, and it is essential for hospitals to have full-time vascular surgery availability.Table IType of consultNontraumaTraumaAll cases regardless of trauma statusIntraoperative consults51103154 (43%)Emergent consults54105159 (44%)Elective consults49049 (13%)Total154 (43%)208 (57%)362 (100%) Open table in a new tab Table IIReason for vascular consultNon-traumaTraumaAll cases regardless of trauma statusUncontrolled hemorrhage335184 (23%)Limb ischemia31135166 (46%)Organ ischemia10212 (3%)Exposure8020100 (28%)Total154 (43%)208 (57%)362 (100%) Open table in a new tab

Current Status and Future Outlook of Additive Manufacturing Technologies for the Reconstruction of the Trachea.

Tracheal stenosis and defects occur congenitally and in patients who have undergone tracheal intubation and tracheostomy due to long-term intensive care. Such issues may also be observed during tracheal removal during malignant head and neck tumor resection. However, to date, no treatment method has been identified that can simultaneously restore the appearance of the tracheal skeleton while maintaining respiratory function in patients with tracheal defects. Therefore, there is an urgent need to develop a method that can maintain tracheal function while simultaneously reconstructing the skeletal structure of the trachea. Under such circumstances, the advent of additive manufacturing technology that can create customized structures using patient medical image data provides new possibilities for tracheal reconstruction surgery. In this study, the three-dimensional (3D) printing and bioprinting technologies used in tracheal reconstruction are summarized, and various research results related to the reconstruction of mucous membranes, cartilage, blood vessels, and muscle tissue, which are tissues required for tracheal reconstruction, are classified. The prospects for 3D-printed tracheas in clinical studies are also described. This review serves as a guide for the development of artificial tracheas and clinical trials using 3D printing and bioprinting.

Development of pre-seeded tissue-engineered vascular grafts in vitro

Current vascular surgery employs reconstruction of occluded blood vessels using autologous grafts. As a considerable proportion of patients lack healthy autologous vessels to be used as the grafts, the development of tissue-engineered, small-diameter vascular grafts has significant clinical relevance. Biodegradable vascular grafts, which have a defined degradation rate upon the implantation, provide an opportunity for the controlled vascular regeneration. Such polymer framework acts as a guiding matrix for organising the patient's newly formed tissues to ensure consistent and complete vessel remodeling. The crucial aspect of tissue-engineered vascular graft regeneration is endothelialisation, as non-endothelialised blood vessels suffer from the thrombosis if having < 5 mm diameter because of low blood flow. This review describes two approaches to stimulate endothelialization. The first is the biofunctionalization of the luminal surface with the bioactive peptides with the following in situ implantation. Using the body as a bioreactor, this approach relies on the selective recruitment of endothelial cells. The second approach includes in vitro pre-seeding of a luminal surface with an endothelial cell monolayer. The development of such pre-seeded vascular grafts requires the choice of an appropriate polymer for the manufacture of a 3D matrix, isolation of endothelial cell culture, and tuning of mechanical stimuli to control the cell specification during the pre-seeding. In addition to the pre-seeding of endothelial cells on the luminal surface, it is necessary to adapt them to the flow to prevent shedding or incorrect orientation. Cell adhesion can be enhanced by the attachment of extracellular matrix proteins to the luminal surface or by mimicking natural blood flow conditions. Sustained mechanical stimuli facilitate the adaptation of endothelial cells to the flow and contribute to the maturation of endothelial progenitor cells.

Endothelialization and smooth muscle cell regeneration capabilities of a bi-layered small diameter vascular graft for blood vessel reconstruction

Despite the tremendous advances in the past few decades, the clinical problems associated with low mechanical strength, thrombosis, and inadequate endothelialization still have not been improved in small diameter vascular grafts. The objective of this study is to design and fabricate a dual layered small-diameter vascular graft by electrospinning process which will mechanically and biologically match the gold standard of blood vessel substitution. The presented graft was composed of polycaprolactone/gelatin (inner layer) and polyurethane/polycaprolactone (outer layer) and fabricated by sequential electrospinning process. Physico-mechanical evaluation, in vitro biocompatibility and hemocompatibility assays were performed for both layers to ensure safe in vivo applications Then, the vascular grafts were successfully implanted into a rat abdominal aorta model. Tubular vascular graft had a nanofibrous and porous outer structure, which provided a conducive micro-environment for smooth muscle cell migration as well as proliferation but the lumen wall had a smooth surface to reduce thrombogenicity and improve endothelialization. Both layers showed excellent biocompatibility and hemocompatibility in all in vitro assays. After three months, the harvested grafts exhibited smooth muscle cell regeneration and complete endothelialization on the graft lumen. The dual layered graft could therefore play a pivotal role in the arena of vascular tissue regeneration application.

Osteogenic Differentiated Human Bone Marrow Stem Cells Contribute to Sprouting Angiogenesis Deceleration via Paracrine Excreted IGFBP7

AbstractDeceleration of sprouting angiogenesis until its final disappearance after blood vessel reconstruction is crucial for controlled tissue repair; however, its underlying mechanism remains unclear. It is reported that osteogenic differentiated bone marrow stem cells (OD‐BMSCs) contribute to sprouting angiogenesis deceleration by releasing intrinsic “OFF” signals. In vitro experiments show that insulin‐like growth factor‐binding protein 7 (IGFBP7) is the main component of OD‐BMSCs paracrine products which could inhibit the tube formation ability of endothelial cells. In addition, cell functional experiments show that IGFBP7 inhibits sprouting angiogenesis by reducing cell migration and tip cell specification. Furthermore, it is found that early IGFBP7 intervention, which accelerates sprouting angiogenesis deceleration during the early stage of healing, impedes bone defect healing. These results demonstrate that OD‐BMSCs could offer intrinsic inhibitory signals on sprouting angiogenesis and the appropriate emergence timing of these signals is crucial to maintain vasculature homeostasis during bone repairing. These results provide insight into the complex interaction between osteogenesis–angiogenesis coupling and suggest the potential therapeutic application of IGFBP7 in regulating vascular homeostasis.

The role of the cerebral and cervical arteries ultrasound examination in migraine diagnosis

Migraine as a primary disease is a very common problem. However, headache attacks that mimic migraine attacks can often be secondary, due to various type of pathology of cervical and cerebral vessels. The common or internal carotid arteries, vertebral arteries, and the anterior, middle, and posterior cerebral arteries, the anterior and posterior communicating arteries, or the basilar artery may be affected. Identification of such diseases is the primary task of differential diagnosis in migraine, especially migraine with aura, and secondary cephalgic syndromes, since in some cases we are talking about life-threatening conditions that require immediate intervention: rupture of brain artery aneurysm or arteriovenous malformation, dissection of one or more cervical arteries. Various types of ultrasound are successfully used to diagnose vascular diseases, ranging from “blind” dopplerography to three-dimensional reconstruction of blood vessels and contrast ultrasound. The defect of the oval window can be complicated by paradoxical microembolism, that can lead to impaired cerebral circulation. This anatomical feature is also available for diagnosis using ultrasound; and once the diagnosis is established, surgical closure of the foramen ovale defect reduces not only the prevalence of migraine with aura attacks, but also the risk of the stroke. This review article discusses the clinical and diagnostic aspects of cerebral aneurysms and arteriovenous malformations, dissection of brachiocephalic arteries’ wall. It also discusses the diagnosis of cerebral arteries’ microembolism, caused by the paradoxical movement of material emboli through non-closure of the foramen ovale, as the cause of one of the most formidable complications of migraine - stroke.

Construction of enzyme-laden vascular scaffolds based on hyaluronic acid oligosaccharides-modified collagen nanofibers for antithrombosis and in-situ endothelialization of tissue-engineered blood vessels

The current use of synthetic grafts often yields low patency in the reconstruction of small-diameter blood vessels owing to the deposition of thrombi and imperfect coverage of the endothelium on the graft lumen. Therefore, the design of vascular scaffolds with antithrombotic performance and endothelialization is greatly required. Herein, we developed an enzyme-laden scaffold based on hyaluronic acid oligosaccharides-modified collagen nanofibers (labeled HA-COL) to improve the anti-platelet capacity and endothelialization of vascular grafts. In this study, HA-COL nanofibers not only encouraged the endothelialization of vascular scaffolds, but acted as an antiplatelet enzyme-laden platform. Apyrase (Apy) and 5’-nucleotidase (5’-NT) were covalently grafted onto the nanofibers, which in turn converted the platelet-sensitive substance: adenosine diphosphate (ADP) into adenosine monophosphate (AMP) and adenosine, thereby, improving the antithrombotic performance of the scaffolds. Notably, the catalytic end-product: adenosine would work in coordination with HA-COL to synergistically enhance the endothelialization of the vascular scaffolds. The results demonstrated that the enzyme-laden scaffolds maintained catalytic performance, reduced platelet adhesion and aggregation, and guaranteed higher patency after 1-month in situ transplantation. Moreover, these scaffolds showed optimal cytocompatibility, tissue compatibility, scaffold biodegradability and tissue regenerative capability during in vivo implantation. Overall, these engineered vascular scaffolds demonstrated their capacity for endothelialization and antithrombotic performance, suggesting their potential for small-diameter vascular tissue engineering applications. Statement of significanceConsidering the critical problems in small-diameter vascular reconstruction, the enzyme-laden vascular scaffolds were prepared for improving in-situ endothelialization and antithrombotic performances of artificial blood vessels. The electrospun HA-COL nanofibers were used as the main matrix materials, which provided favorable structural templates for the regeneration of vasculature and functioned as a platform for the loading of enzymes. The enzyme-laden scaffolds with the biomimetic cascading reaction would convert ADP into adenosine, thereby, decreasing the sensitivity of platelets and improving the antithrombotic performance of tissue-engineered blood vessels (TEBVs). The nanofibrous scaffolds exhibited optimal cytocompatibility, tissue compatibility and regenerative capability, working together with catalytic products of dual-enzyme reaction that would synergistically contribute to TEBVs endothelialization. This study provides a new method for the improvement of in-situ endothelialization of small-diameter TEBVs while qualified with antithrombotic performance.

Short-wave infrared computed tomography.

We demonstrate a short-wave infrared computed tomography method. It uses a fiber-coupled 1.44µm super-luminescent diode as light source, a PbSe photodiode as infrared detector, and an electronically controlled rotation and translation stage for high-speed Radon scanning. It is a safe and low power nondestructive testing method that can be used for the detection of plastic polymers, biological tissue and other materials that visible light cannot penetrate. We analyze the theoretical resolution of the method and build a short-wave infrared computed tomography system, which realizes the tomography and 3D reconstruction of black plastic bottles and artificial blood vessels. The measured resolution reaches10µm.

Small extracellular vesicles derived from hypoxic mesenchymal stem cells promote vascularized bone regeneration through the miR-210-3p/EFNA3/PI3K pathway

Angiogenesis is closely coupled with osteogenesis and has equal importance. Thus, promoting angiogenesis during the bone repair process is vital for ideal bone regeneration. As important mediators of cell-cell communication and biological homeostasis, mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) have been proved to be highly involved in bone and vascular regeneration. Because hypoxia microenvironment promotes the proangiogenic activity of MSCs, in the present study, we investigate the effect and underlying molecular mechanisms of sEVs from hypoxia-preconditioned MSCs (hypo-sEVs) on angiogenesis and develop an effective strategy to promote vascularized bone regeneration. Compared to sEVs from normoxia MSCs (nor-sEVs), hypo-sEVs promoted the proliferation, migration, and angiogenesis of HUVECs and ultimately enhanced bone regeneration and new blood vessel reconstruction in a critical-size calvarial bone defect model. miRNA sequence and the verified results showed that miR-210-3p in hypo-sEVs was increased via HIF-1α under hypoxia. The upregulated miR-210-3p in hypo-sEVs promoted angiogenesis by downregulating EFNA3 expression and enhancing the phosphorylation of the PI3K/AKT pathway. Thus, this study suggests a successful strategy to enhance vascularized bone regeneration by utilizing hypo-sEVs via the miR-210-3p/EFNA3/PI3K/AKT pathway. Statement of significanceConsidering the significance of vascularization in ideal bone regeneration, strategies to promote angiogenesis during bone repair are required. Hypoxia microenvironment can promote the proangiogenic potential of mesenchymal stem cells (MSCs). Nonetheless, the therapeutic effect of small extracellular vesicles (sEVs) from hypoxia-preconditioned MSCs on cranio-maxillofacial bone defect remains unknown, and the underlying mechanism is poorly understood. This study shows that hypo-sEVs significantly enhance the proliferation, migration, and angiogenesis of HUVECs as well as promote vascularized bone formation. Moreover, this work indicates that HIF-1α can induce overexpression of miR-210-3p under hypoxia, and miR-210-3p can hinder EFNA3 expression and subsequently activate the PI3K/AKT pathway. The application of hypo-sEVs provides a facile and promising strategy to promote vascularized bone regeneration in a critical-size bone defect model.

Reconstruction of the superficial femoral vessels with muscle flap coverage for soft tissue sarcomas of the proximal thigh.

BackgroundSurgical resection of soft tissue sarcoma with a margin of healthy tissue may necessitate resection and reconstruction of major blood vessels together with soft tissues of the proximal thigh to preserve the limb. The long‐term functional outcomes of these reconstructions remain unestablished. The aim of this report was to assess the vascular and functional outcomes of soft tissue sarcoma patients with femoral vessel reconstructions.Patients and MethodsPatients who had undergone oncovascular reconstruction during the treatment of proximal thigh soft tissue sarcoma in 2014–2020 were reviewed for details of the vascular and soft tissue reconstructions, and the oncological and functional outcomes. This included eight patients of a median age 59 (range 19–77) years. All had a reconstruction of at least the superficial femoral artery and vein as well as soft tissue reconstruction with a muscle flap. All vessel reconstructions were done with either autologous vein (six grafts/four patients) or allograft (10 grafts/six patients). A microvascular latissimus dorsi flap, with a skin island, was incorporated to cover the vascular grafts in five patients. A pedicled sartorius or gracilis muscle flap was used to fill the defect in three patients.ResultsGraft patency was assessed in seven patients with a median follow‐up of 48 (1–76) months. The arterial graft was patent in 6/8 and the vein graft in 2/8 patients. The gait had returned to normal in five of the six patients assessed. The median MTSS was 70 (43–87)% and the TESS 90 (75–100)%. No local recurrence of the sarcoma was detected.ConclusionsVascular reconstruction combined with soft tissue reconstruction enables limb‐sparing surgery in patients with soft tissue sarcoma involving proximal femoral vessels. Although the surgeries are complex with high early morbidity, the achieved long‐term functional outcomes are worthwhile.