Lipotransfer has been applied in breast augmentation surgery for several years and the resident adipose-derived stem cells (ASCs) play an important role in enhancing fat graft survival. However, the ...interaction between ASCs and mammary epithelium is not fully understood. Many studies have shown that ASCs have a tumor-supportive effect in breast cancer. To the best of our knowledge, this is the first study on the effect of mammary epithelial cells on the human ASCs in 3D culture. ASCs were cultivated on matrigel in the conditioned medium (CM) prepared from a human breast epithelial cell line (HBL-100). The ASCs formed KRT18-positive acini-like structures after stimulation with breast epithelial cells. The expression of epithelial genes (CDH1 and KRT18) was up-regulated while the expression of mesenchymal specific genes (CDH2 and VIM) was down-regulated as determined by qRT-PCR. The stemness marker (CD29) and angiogenic factors (CD31 and VEGF) were also down-regulated as examined by immunofluorescence. In addition, the CM obtained from HBL-100 enhanced the migration and inhibited the adipogenic differentiation of ASCs. These results demonstrate that ASCs have the ability to transform into epithelial-like cells when cultured with mammary epithelial cells. Given these observations, we infer that ASCs have a positive effect on lipotransfer, not only due to their ability to secrete growth factors, but also due to their direct participation in the formation of new breast tissue.
We present a novel method for local image feature matching. Instead of performing image feature detection, description, and matching sequentially, we propose to first establish pixel-wise dense ...matches at a coarse level and later refine the good matches at a fine level. In contrast to dense methods that use a cost volume to search correspondences, we use self and cross attention layers in Transformer to obtain feature descriptors that are conditioned on both images. The global receptive field provided by Transformer enables our method to produce dense matches in low-texture areas, where feature detectors usually struggle to produce repeatable interest points. The experiments on indoor and outdoor datasets show that LoFTR outperforms state-of-the-art methods by a large margin. LoFTR also ranks first on two public benchmarks of visual localization among the published methods. Code is available at our project page: https://zju3dv.github.io/loftr/.
Biomineralization of natural polymers in simulated body fluid (SBF) can significantly improve its biocompatibility, osteoconductivity, and osteoinductivity because of the hydroxyapatite (HAp) ...deposition. Nevertheless, the superficial HAp crystal deposition hamper the deep inorganic ions exchange in porous microgels, thus gradually leading to a nonuniform regeneration effect. Inspired by the pearl forming process, this article uses the microarray chips to fabricate the multi-layer mineralized graphene oxide (GO)-collagen (Col)-hydroxyapatite (HAp) microgel, denoted as MMGCH. These fabricated MMGCH microgels exhibit porous structure and uniform HAp distribution. Furthermore, the suitable microenvironment offered by microgel promotes the time-dependent proliferation and osteogenic differentiation of stem cells, which resulted in upregulated osteogenesis-related genes and proteins, such as alkaline phosphatase, osteocalcin, and collagen-1. Finally, the MMGCH microgels possess favorable bone regeneration capacities both in cranial bone defects and mandibular bone defects via providing a suitable microenvironment for host-derived cells to form new bone tissues. This work presents a biomimetic means aiming to achieve full-thickness and uniform HAp deposition in hydrogel for bone defect repair.
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•Microarray chips for multi-layered materials synthesis with multi-layer mineralization of hydroxyapatite.•Pearl-inspired graphene oxide-collagen microgel with uniformly distributed hydroxyapatite was first reported.•The method of improving mineralization efficiency can be applied to various types of polymers.•The fabricated pearl-inspired microgel showed favorable bone regeneration effects both in cranial and mandibular bone defect models.
Uncertainty of target motion, limited perception ability of onboard cameras, and constrained control have brought new challenges to unmanned aerial vehicle (UAV) dynamic target tracking control. In ...virtue of the powerful fitting ability and learning ability of the neural network, this paper proposes a new deep reinforcement learning (DRL)-based end-to-end control method for UAV dynamic target tracking. Firstly, a DRL-based framework using onboard camera image is established, which simplifies the traditional modularization paradigm. Secondly, neural network architecture, reward functions, and soft actor-critic (SAC)-based speed command perception algorithm are designed to train the policy network. The output of the policy network is denormalized and directly used as speed control command, which realizes the UAV dynamic target tracking. Finally, the feasibility of the proposed end-to-end control method is demonstrated by numerical simulation. The results show that the proposed DRL-based framework is feasible to simplify the traditional modularization paradigm. The UAV can track the dynamic target with rapidly changing of speed and direction.
Mesenchymal stem cells (MSC)-based tissue engineered breast represent the visible future for breast reconstruction after mastectomy. However, autologous MSCs might not be appropriate for the large ...graft construction due to cell senescence during excessive cell expansion, thus hindering its further off-the-shelf application. The human umbilical cord mesenchymal stem cells (hUCMSCs) have been found to induce low immune response and can be easily stored, making them ideal for off-the-shelf tissue engineering application. Here, we explored the feasibility of using umbilical cord mesenchymal stem cells as tissue-engineered breast seed cells.
The allogenic hUCMSCs were injected into transplanted fat tissue with or without breast scaffolds as an alternative for breast tissue engineering in vivo, and its potential mechanism of angiogenesis in vitro was explored.
Transplantation of hUCMSCs promoted proliferation, migration, and angiogenesis of human umbilical vein endothelial cells (HUVECs) through paracrine mechanism by activating the integrin β1/ERK1/2/HIF-1α/VEGF-A signaling pathway. Histological examination of grafted fat revealed that the group which received hUCMSCs transplantation had more fat tissue (93.60 ± 2.40) % and fewer MAC2
CD206
M1 macrophages (0.50 ± 0.47) cells/field compared to the control group fat tissue (45.42 ± 5.96) and macrophage cells/field (5.00 ± 2.23). Moreover, the hUCMSCs- labeled with a tracing dye differentiated into adipocytes and vascular endothelial cells in the adipose tissue. When applied to the tissue-engineered breast with a scaffold, the group treated with hUCMSCs had more adipose tissues and CD31
cells than the control group.
These results demonstrate that allogeneic hUCMSCs promote the regeneration of adipose tissue and can be used to construct a tissue engineered breast.
Hydrogel-based micro-tissue engineering technique, a bottom-up approach, is promising in constructing soft tissue of large size with homogeneous spatial distribution and superior regeneration ...capacity compared to the top-down approach. However, most of the studies employed micro-tissues with simple mesenchymal stem cells, which could hardly meet the growth of matrix and vessels. Therefore, we recommend a dual micro-tissues assembly strategy to construct vascularized tissue-engineered breast grafts (TEBGs). Adipose micro-tissues (AMs) and vessel micro-tissues (VMs) were fabricated by seeding adipose-derived stem cells (ADSCs) and human umbilical vein endothelial cells (HUVECs) on collagen microgels (COLs) with a uniform diameter of ∼250 μm, respectively. TEBGs were constructed by injecting the dual micro-tissues into 3D printed breast-like Thermoplastic Urethane (TPU) scaffolds, then implanted into the subcutaneous pockets on the back of nude mice. After 3 months of implantation, TEBGs based on dual micro-tissues performed larger volume of adipose tissue regeneration and neo-vessel formation compared to TEBGs based on single AMs. This study extends the application of micro-tissue engineering technique for the construction of soft grafts, and is expected to be useful for creating heterogeneous tissue constructs in the future.
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Due to wavelength-dependent light absorption and scattering, underwater images often appear with a colour cast and blurry details. Most existing deep learning methods utilize a single input ...end-to-end network structure, which leads to a single form and content of the extracted features. To address these problems, we present a novel multi-feature underwater image enhancement method via embedded fusion mechanism (MFEF). We find that the quality of reconstruction results is affected by the quality of the input image to some extent, and use pre-processing to obtain high-quality images, which can improve the final reconstruction effect. We introduce the white balance (WB) algorithm and the contrast-limited adaptive histogram equalization (CLAHE) algorithm employing multiple path inputs to extract different forms of rich features in multiple views. To fully interact with features from multiple views, we design a multi-feature fusion (MFF) module to fuse derived image features. We suggest a novel pixel-weighted channel attention module (PCAM) that calibrates the detailed features of the degraded images using a weight matrix to give diverse weights to the encoded features. Ultimately, our network utilizes a fusion mechanism-based encoder and decoder that can be applied to restore various underwater scenes. In the UIEB dataset, our PSNR increased by 10.2% compared to that of Ucolor. Extensive experimental results demonstrate that the MFEF method outperforms other state-of-the-art underwater image enhancement methods in various real-world datasets.
Skin fibrosis, a pathological process featured by fibroblast activation and extracellular matrix (ECM) deposition, makes a significant contribution to morbidity. Studies have identified biomechanics ...as the central element in the complex network of fibrogenesis that drives the profibrotic feedback loop. In this study, we found that the acetylation of α‐tubulin at lysine 40 (K40) was augmented in fibrotic skin tissues. Further analysis showed that α‐tubulin acetylation is required for fibroblast activation, including contraction, migration, and ECM deposition. More importantly, we revealed that biomechanics‐induced upregulation of K40 acetylation promotes fibrosis by mediating mechanosensitive Yes‐associated protein S127 dephosphorylation and its cytoplasm nucleus shuttle. Furthermore, we demonstrated that the knockdown of α‐tubulin acetyltransferase 1 could rescue the K40 acetylation upregulation caused by increased matrix rigidity and ameliorate skin fibrosis both in vivo and in vitro. Herein, we highlight the critical role of α‐tubulin acetylation in matrix stiffness‐induced skin fibrosis and clarify a possible molecular mechanism. Our research suggests α‐tubulin acetylation as a potential target for drug design and therapeutic intervention.
Matrix stiffness-induced α‐tubulin acetylation is required for skin fibrosis formation.
Acetylated α‐tubulin at K40 promoted fibroblast activation by dephosphorylating Yes‐associated protein and maintaining its nuclear retention.
Downregulating K40 acetylation of α‐tubulin through knockdown of α‐tubulin acetyltransferase 1 could ameliorate fibrosis formation.
Background. Mesenchymal stromal cells (MSCs) and their secreted extracellular vesicles (MSC-EVs) possess similar proregenerative effects when injected into defects immediately following trauma. ...However, MSC-EVs are superior to MSCs in terms of storage and rejection reflection, while immediate administration of MSC-EVs is related to several target cells for most donor cells die within few weeks. Besides, the inflammatory cascade is incited, providing an unfavorable environment for target cells. We hypothesized that delayed injection of MSC-EVs might have priority on tissue regeneration than instant injection. Method. Extracellular vesicles isolated from adipose-derived mesenchymal stromal cells (ADSC-EVs) were administered into human umbilical vein endothelial cells (HUVECs) in vitro at different doses. The migration of HUVECs was assessed using the scratch wound healing assay, whereas the length of tubes and number of vessel-like structures formed by HUVECs were determined using tube formation assay. Next, 24 BALB/c nude mice were randomly divided into three groups (n=8). For the EV-delayed group, ADSC-EVs were injected into transplanted fat a week later than the EV-immediate group. The volume and weight of grafts were measured at 3 months after fat transplantation. Further, the number of CD31-possitive vessels and CD206-possitive cells in the fat grafts was quantified. Results. Compared with the EV-immediate group, the EV-delayed group had a higher fat tissue retention volume (0.11±0.02 mL versus 0.08±0.01 mL), more neovessels (31.00±4.60 versus 24.20±3.97), and fewer cysts. Furthermore, there were more Ki67-positive cells (25.40±7.14 versus 16.20±4.17) and CD206-positive M2 macrophages cells (23.60±3.44 versus 14.00±3.85) in the EV-delayed group than in the EV-immediate group. Conclusion. Delayed injection of ADSC-EVs promotes fat graft volume retention by stimulating angiogenesis. These findings suggest that delayed supplementation might be a more effective strategy for the application of MSC-EVs in tissue regeneration.
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