Suture Model Research Articles

Simple incision and suture modeling on fixed structured grids

This paper presents a simple yet versatile approach to simulate skin incisions and suturing using nonlinear finite element analysis on a fixed structured grid with a spring-based suture model. Incisions and wounds are introduced by element removal and the sutures are discretely modeled by applying linear constraint relations pairwise to groups of nodes. Two numerical examples utilize the closing of an elliptical wound to study the influence of the number of sutures and their location, and two test cases use the Z-plasty transposition flap technique to investigate the versatility of the proposed method and for comparison with state-of-the-art results. The results indicate that the presented method is able to recreate literature results to an acceptable level of accuracy. Further, the method proves versatile due to the ability to freely introduce incisions and wounds onto the fixed grid modeling domain without remeshing. Lastly, the two main advantages of the discrete suture representation are the ability to capture local stress concentrations near the sutures and the full freedom in placing the sutures.

Establishment and evaluation of a stable and reliable rat model of peritoneal adhesions

BackgroundIn this study, we aimed to establish a stable and standardized animal model of peritoneal adhesions. MethodsForty-eight male Sprague–Dawley rats were randomly divided (n = 12 each) into blank control, classic cecum sidewall, ischemic button, and cecum–sidewall suture groups. The modified American Fertility Society adhesion score was used on postoperative day 7 to evaluate adhesions. Sixty male Sprague–Dawley rats were used to dynamically observe the adhesion characteristics of cecum–sidewall ischemic injury suture model at different time points (n = 60, randomly divided into groups a–e with 12 rats each). The modified American Fertility Society and Zühlke histologic scoring systems, hematoxylin-eosin staining, Masson staining, and computed tomography of the abdomen were used to evaluate adhesions on postoperative days 1, 3, 5, 7, and 14. ResultsNo peritoneal adhesions were observed in the blank control group on postoperative day 7. In the classic cecum sidewall group, 8 rats had inconsistent adhesions, which had a modified American Fertility Society adhesion score of 2.25 ± 1.96. All rats in the ischemic button and cecum–sidewall suture groups developed significant adhesions with modified American Fertility Society scores of 3.08 ± 1.31 and 4.67 ± 0.78, respectively. When the modified American Fertility Society score was used, statistically significant differences were observed between the classic cecum sidewall groups and cecum–sidewall suture groups and between the ischemic button groups and cecum–sidewall suture groups. All animals in groups a–e developed adhesions; adhesion scores increased gradually with time. ConclusionsThe cecum–sidewall ischemic injury suture model is a stable and standardized animal model of peritoneal adhesions.

Ischemia-reperfusion injury in a salvaged penumbra: Longitudinal high-tesla perfusion magnetic resonance imaging in a rat model

IntroductionAlthough ischemia-reperfusion (I/R) injury varies between cortical and subcortical regions, its effects on specific regions remain unclear. In this study, we used various magnetic resonance imaging (MRI) techniques to examine the spatiotemporal dynamics of I/R injury within the salvaged ischemic penumbra (IP) and reperfused ischemic core (IC) of a rodent model, with the aim of enhancing therapeutic strategies by elucidating these dynamics. Materials and methodsA total of 17 Sprague–Dawley rats were subjected to 1 h of transient middle cerebral artery occlusion with a suture model. MRI, including diffusion tensor imaging (DTI), T2-weighted imaging, perfusion-weighted imaging, and T1 mapping, was conducted at multiple time points for up to 5 days during the I/R phases. The spatiotemporal dynamics of blood–brain barrier (BBB) modifications were characterized through changes in T1 within the IP and IC regions and compared with mean diffusivity (MD), T2, and cerebral blood flow. ResultsDuring the I/R phases, the MD of the IC initially decreased, normalized after recanalization, decreased again at 24 h, and peaked on day 5. By contrast, the IP remained relatively stable. Both the IP and IC exhibited hyperperfusion, with the IP reaching its peak at 24 h, followed by resolution, whereas hyperperfusion was maintained in the IC until day 5. Despite hyperperfusion, the IP maintained an intact BBB, whereas the IC experienced persistent BBB leakage. At 24 h, the IC exhibited an increase in the T2 signal, corresponding to regions exhibiting BBB disruption at 5 days. ConclusionsHyperperfusion and BBB impairment have distinct patterns in the IP and IC. Quantitative T1 mapping may serve as a supplementary tool for the early detection of malignant hyperemia accompanied by BBB leakage, aiding in precise interventions after recanalization. These findings underscore the value of MRI markers in monitoring ischemia-specific regions and customizing therapeutic strategies to improve patient outcomes.

Establishment of a pMCAO model in SD rats and screening for behavioral indicators suitable for long-term monitoring

ABSTRACT Objective: This study aimed to establish a permanent middle cerebral artery occlusion (pMCAO) model in rats to simulate the pathological process of stroke patients with no reperfusion. And screen highly sensitive items that could be used to detect long-term behavioral abilities in rat of intraluminal suture models. Method: Established the pMCAO model then tested the rats for the bilateral asymmetry, modified neurological severity score, grid-walking, cylinder, rotating, and water maze test from week 1 to week 16. Results: The infarct volume of the model rats was stable (26.72% ±1.86%). The sensorimotor test of bilateral asymmetry, grid-walking, cylinder, and mNSS test showed significant differences from week 1 to week 16 after injury. The water maze test at week 16 showed significant differences in spatial exploration and learning ability between the two groups. We confirmed that there was no significant difference between MRI and TTC staining in detecting the degree of brain injury, which facilitated the diversity of subsequent detection methods. We also confirmed that at multiple time points, grid, cylinder and water maze test were significantly positively correlated with rat brain infarct volume. Conclusion: They are suitable for the long-term observation of behaviors in the sequela stage of stroke in rat.

Metabasites from the Central East Kunlun Orogenic Belt Inform a New Suture Model for Subduction and Collision in the Early Paleozoic Proto-Tethys Ocean

The discovery of eclogite outcrops in the East Kunlun Orogen Belt (EKOB) has confirmed the existence of an Early Paleozoic HP-UHP metamorphic belt. However, the protoliths and metamorphic histories of widespread metabasites remain poorly constrained. We collected three types of metabasites from the central part of EKOB. We present an integrated study of petrography, whole-rock geochemistry, Sr-Nd isotopes, estimated P–T conditions, and zircon U-Pb isotope ages. The results show that amphibolites and retrograde eclogites have clockwise P–T paths with peak conditions of, respectively, 11–12 kbar and 675–695 °C, and 21.5–22.2 kbar and 715–750 °C. Zircon dating of metabasites from Dagele yields Late Ordovician (~449 Ma) to Early Silurian (~440 Ma) protolith ages and Early Devonian (~414 Ma) amphibolite facies metamorphic ages. Retrograde eclogites from east Nuomuhong have a protolith age of ~902 Ma and metamorphic ages of ~418 Ma, consistent with other eclogites from East Kunlun. Our data suggest that the protoliths of Dagele metabasites represent arc-type magmatism during the subduction of a small back-arc oceanic basin. Instead, the protoliths of retrograde eclogites are Neoproterozoic tholeiitic basalts emplaced into continental crust and subsequently deeply subducted. We develop a new model for Early Paleozoic subduction and collision in the East Kunlun region, emphasizing the role of ‘dominant’ and ‘secondary’ suture boundaries. This model helps explain the ages and metamorphic histories of the metabasites studied here and offers new perspectives on the evolution of the Proto-Tethys Ocean.

Simulation training of laparoscopic biliary-enteric anastomosis with a three-dimensional-printed model leads to better skill transfer: a randomized controlled trial.

A new simulation model and training curriculum for laparoscopic bilioenteric anastomosis has been developed. Currently, this concept lacks evidence for the transfer of skills from simulation to clinical settings. This study was conducted to determine whether training with a three-dimensional (3D) bilioenteric anastomosis model result in greater transfer of skills than traditional training methods involving video observation and a general suture model. Fifteen general surgeons with no prior experience in laparoscopic biliary-enteric anastomosis were included in this study and randomised into three training groups: video observation only, practice using a general suture model, and practice using a 3D-printed biliary-enteric anastomosis model. Following five training sessions, each surgeon was asked to perform a laparoscopic biliary-enteric anastomosis procedure on an isolated swine organ model. The operative time and performance scores of the procedure were recorded and compared among the three training groups. The operation time in the 3D-printed model group was significantly shorter than the suture and video observation groups ( P =0.040). Furthermore, the performance score of the 3D-printed model group was significantly higher than those of the suture and video observation groups ( P =0.001). Finally, the goal score for laparoscopic biliary-enteric anastomosis in the isolated swine organ model was significantly higher in the 3D model group than in the suture and video observation groups ( P =0.004). The utilisation of a novel 3D-printed model for simulation training in laparoscopic biliary-enteric anastomosis facilitates improved skill acquisition and transferability to an animal setting compared with traditional training techniques.

Imaging of Endometriotic Lesions Using cRGD-MN Probe in a Mouse Model of Endometriosis

Approximately 10% of women suffer from endometriosis during their reproductive years. This disease is a chronic debilitating condition whose etiology for lesion implantation and survival heavily relies on adhesion and angiogenic factors. Currently, there are no clinically approved agents for its detection. In this study, we evaluated cRGD-peptide-conjugated nanoparticles (RGD-Cy5.5-MN) to detect lesions using magnetic resonance imaging (MRI) in a mouse model of endometriosis. We utilized a luciferase-expressing murine suture model of endometriosis. Imaging was performed before and after 24 h following the intravenous injection of RGD-Cy5.5-MN or control nanoparticles (Cy5.5-MN). Next, we performed biodistribution of RGD-Cy5.5-MN and correlative fluorescence microscopy of lesions stained for CD34. Tissue iron content was determined using inductively coupled plasma optical emission spectrometry (ICP-OES). Our results demonstrated that targeting endometriotic lesions with RGD-Cy5.5-MN resulted in a significantly higher delta T2* upon its accumulation compared to Cy5.5-MN. ICP-OES showed significantly higher iron content in the lesions of the animals in the experimental group compared to the lesions of the animals in the control group. Histology showed colocalization of Cy5.5 signal from RGD-Cy5.5-MN with CD34 in the lesions pointing to the targeted nature of the probe. This work offers initial proof-of-concept for targeting angiogenesis in endometriosis which can be useful for potential clinical diagnostic and therapeutic approaches for treating this disease.

Abstract TP287: Estrous Cycle Stages and Cerebral Blood Flow: Implications for Ischemic Tolerance in Stroke

Introduction: Previous stroke studies in female rodents have demonstrated that the severity of ischemic damage is differentially impacted by the estrous cycle. Estrogen is considered to be neuroprotective, but it is unclear whether this protection is dependent on the vasodilator properties of estrogen. In this study, we investigated the impact of estrus cycle stage on stroke lesion volume and whether that impact was dependent on cerebral blood flow (CBF) changes during stroke. Methods: Ischemia was induced in adult ( 10 weeks) male and female Sprague-Dawley rats by 30 minutes middle cerebral artery occlusion (MCAO) using the suture model. Prior to the stroke procedure, the phases of the estrous cycle (proestrus(P), estrus(E), metestrus(M) and diestrus (D)) were determined by vaginal smear tests in female rats. Cerebral blood flow (CBF) was measured by laser doppler and infarct volume were measured by TTC staining at d2 post-stroke. Results: Females in proestrus and diestrus (P/D) stages of the estrous cycle, which have reportedly high levels of estrogen, had significantly (p<0.05) smaller CBF decreases during ischemia and a trend for smaller infarcts than those in estrous and metestrus stages, which have lower estrogen levels. This suggests that the protective effects of estrogen may be related to effects on blood flow. However, when compared to male rats, females in P/D stages had significantly (p<0.05) smaller brain infarcts despite having similar CBF decreases. This implies that additional mechanisms are responsible for the neuroprotection observed in females when compared to males. Conclusion: Estrous cycle stage affects CBF decrease during ischemia, but this does not account for the difference in infarct size observed between male and female rats. Our study indicates that multiple mechanisms are responsible for ischemic tolerance in specific stages of the estrous cycle. Keywords: stroke, estrous cycle, CBF, estrogen

Analysis of material parameter uncertainty propagation in preoperative flap suture simulation

Skin flap transplantation is the most commonly used method to repair tissue defect and cover the wound. In clinic, finite element method is often used to design the pre-operation scheme of flap suture. However, the material parameters of skin flap are uncertain due to experimental errors and differences in body parts. How to consider the influence of material parameter uncertainty on the mechanical response of flap suture in the finite element modeling is an urgent problem to be solved at present. Therefore, the influence of material parameter uncertainty propagation in skin flap suture simulation was studied, Firstly, the geometric model of clinical patient’s hand wound was constructed by using reverse modeling technology, the patient’s three-dimensional wound was unfolded into a flat surface by using curved surface expansion method, yielding a preliminary design contour for the patient’s transplant flap. Based on the acquired patient wound geometry model, the finite element model of flap suture with different fiber orientations and different sizes was constructed in Abaqus, and the uncertainty propagation analysis method based on Monte Carlo simulation combined with surrogate model technology was further used to analyze the stress response of flap suture considering the uncertainty of material parameters. Results showed that the overall stress value was relatively lower when the average fiber orientation was 45°. which could be used as the optimal direction for the flap excision. when the preliminary design contour of the flap was scaled down within 90%, the stress value after flap suturing remained within a safe range.

Subject playing with flat images: Transmedia spreadability of anime and manga character images

Anime and manga characters are so ubiquitous in Japan that people see them anywhere, regardless of public or private. The two-dimensional flatness of line drawing allows the character images to straddle the boundaries of the worlds of works and media. The analysis of individual artworks needs to be revised to understand the transmedia spreadability of characters and our living conditions. This paper, thus, overviews the preceding discussions of anime and manga scholars on human-character relations and compares them with the theory of subject formation in film studies, whose realist tendency once emphasized the three-dimensional space and time. While psychoanalysis-influenced theories such as suture and male gaze model after one-point perspective and subordinate two-dimensionality, Thomas Lamarre formulates a de-unified perspective in relation to the multilayered image field of Japanese anime. In conjunction with the orientation of cultural and fan studies to emphasize audience agency, this article discusses the de-unified perspective on flat images which has the potential for understanding the complexity of subject formation through the interplay with two-dimensional images.

The potential of cell-assembled extracellular matrix for biological sutures: A promising innovation.

Most surgical procedures require using suture materials that are mechanically efficient and accepted by the patient's body. These sutures are essentially composed of synthetic polymers. However, once implanted in patients, they are recognized as foreign bodies and generate chronic inflammation. Thereafter, the patient's immune system will degrade, encapsulate, or even expel the materials. Our innovation, the Cell-Assembled extracellular Matrix (CAM), synthesized from mesenchymal cells, replicates native tissue environments and promotes integration, reducing complications. In a recent study, we introduced CAM-based biological sutures, demonstrating favorable mechanical properties and vascular surgery compatibility. Controlled culture duration tailors CAM for specific applications. Diverse CAM-based suture models were ex vivo tested in animal aorta anastomoses, confirming compatibility. In vivo carotid anastomoses in sheep validated the clinical significance of these innovative sutures. CAM sutures, derived from immunologically favorable allogeneic fibroblast cells, offer high biocompatibility and exhibit superior mechanical properties compared to synthetics by reducing permeability and increasing burst resistance. In vivo testing in sheep underscores clinical applicability, achieving hemostasis and immediate complication prevention. Importantly, CAM-based sutures are compatible with existing vascular surgery techniques, facilitating adoption by surgeons. In conclusion, our findings underscore the effectiveness and clinical significance of these innovative biological sutures.

Development and Validation of a Uterine Prolapse, Epidural, and Vaginal Suture Model.

Uterine prolapses sporadically present to bovine practitioners. Exposing veterinary students to this is challenging due to the inability to replicate a live animal prolapses in a teaching environment. The objective of this study was to develop a model that represents each step of the process of correcting a uterine prolapse and to perform a validation study of the model and rubric used to score performance using a skill comparison between experienced veterinarians and novices (students). The model was designed and built, and 27 students and 18 bovine veterinarians were recruited to participate in the evaluation of this model. Each participant performed each step of the model while being video recorded. Following model use, all participants completed a survey on their prior experiences and opinions of the model. Videos were viewed, and performances scored by one author using a rubric. Opinions on the model were mostly favorable in regard to use and realistic experience. There was no significant difference between the scores of veterinarians and veterinary students. However, there was an association with an excellent level of global rating scores for veterinarians while the veterinary student participants were associated with borderline satisfactory to good competency levels except for the epidural. There was a statistically significant association between the global rating scores and the check list competency levels. The lack of significant difference may be attributed to students previous experiences Based on feedback from the survey responses, the model will be used in clinical skills labs to provide experience in this area.

Finite element analysis of the knee joint stress after partial meniscectomy for meniscus horizontal cleavage tears

ObjectiveTo establish a finite element model of meniscus horizontal cleavage and partial resection, to simulate the mechanical changes of knee joint under 4 flexion angles, and to explore what is the optimal surgical plan. MethodsWe used Mimics Research, Geomagic Wrap, and SolidWorks computer software to reconstruct the 3D model of the knee joint, and then produced the horizontal cleavage tears model of the internal and lateral meniscus, the suture model, and the partial meniscectomy model. These models were assembled into a complete knee joint in SolidWorks software, and corresponding loads and boundary constraints were added to these models in ANSYS software to simulate the changing trend of pressure and shear force on femoral condylar cartilage, meniscus, and tibial cartilage under the flexion angles of 0°, 10°, 20°, 30° and 40° of the knee joint. At the same time, the difference of force area between medial interventricular and lateral interventricular of knee joint under four states of bending the knee was compared, to explore the different effects of different surgical methods on knee joint after horizontal meniscus tear. ResultsWithin the four medial meniscus injury models, the lowest peak internal pressure and shear force of the knee joint was observed in the meniscal suture model; the highest values were found in the bilateral leaflet resection model and the inferior leaflet resection model; the changes of pressure, shear force and stress area in the superior leaflet resection model were the most similar to the changes of the knee model with the meniscal suture model. ConclusionSuture repair is the best way to maintain the force relationship in the knee joint. However, resection of the superior leaflet of the meniscus is also a reliable choice when suture repair is difficult.

An Objective Method for Assessing the Realism of Simulation Models

Our team created an experimental simulation model of a skin suture, and to assess the level of realism, we applied a method of objective assessment of physical properties on specialized equipment and carried out a comparative assessment of various models based on the data obtained. The objective assessment method can be used as an additional criterion to prove the realism of the simulation model. Based on the data obtained, it is possible to produce an artificial reusable skin suture simulator, which will be as close as possible in physical properties to human skin.

Measuring hand movement for suturing skill assessment: A simulation-based study

BackgroundTo maximize patient safety, surgical skills education is increasingly adopting simulation-based curricula for formative skills assessment and training. However, many standardized assessment tools rely on human raters for performance assessment, which is resource-intensive and subjective. Simulators that provide automated and objective metrics from sensor data can address this limitation. We present an instrumented bench suturing simulator, patterned after the clock face radial suturing model from the Fundamentals of Vascular Surgery, for automated and objective assessment of open suturing skills. MethodsFor this study, 97 participants (35 attending surgeons, 32 residents, and 30 novices) were recruited at national vascular conferences. Automated hand motion metrics, especially focusing on rotational motion analysis, were developed from the inertial measurement unit attached to participants’ hands, and the proposed suite of metrics was used to differentiate between the skill levels of the 3 groups. ResultsAttendings’ and residents’ performances were found to be significantly different from novices for all metrics. Moreover, most of our novel metrics could successfully distinguish between finer skill differences between attending and resident groups. In contrast, traditional operative skill metrics, such as time and path length, were unable to distinguish attendings from residents. ConclusionThis study provides evidence for the effectiveness of rotational motion analysis in assessing suturing skills. The suite of inertial measurement unit-based hand motion metrics introduced in this study allows for the incorporation of hand movement data for suturing skill assessment.

Novel mesh suture may resist bone cutting seen with wire-based sternal closures.

Sternal dehiscence is frequently associated with wire-based closures cutting through fragile bone, allowing sternal motion, separation, and infection. We investigated whether bone cutting could be limited by using a newly available mesh suture with improved force distribution. Five sternal models were closed using 8 interrupted single sternal wires, double sternal wires, braided poly(ethylene terephthalate) sutures, single-wrapped mesh sutures, or double-wrapped mesh sutures. To simulate chest-wall forces, closed sternal models were pulled apart using 1020N of axial force applied incrementally. Double sternal wire and double-wrapped mesh suture were further compared by closing 3 new models with each material and subjecting these models to cyclic loading cycles, simulating breathing and coughing. Image analysis of needle hole size measured "bone cutting" by each closure material and sternal distraction as a function of force. All models exhibited maximal separation at the xiphoid. During axial loading, needle hole size increased 7.2% in the double-wrapped mesh suture model and 9.2% in the double-wire model. Single-wrapped mesh suture, single wires, and braided poly(ethylene terephthalate) extended needle hole size by 6.7%, 47.0%, and 168.3% of original size, respectively. The double-wire model resisted sternal distraction best, separating 0.285cm at the xiphoid. During cyclic loading, mesh suture exhibited significantly less bone cutting (P=.02) than double wire, with comparable levels of sternal separation (P=.07). Mesh suture may resist bone cutting seen in sternal wire closure in bone models with comparable distraction to currently used sternal closure methods.

Detection of Endometriosis Lesions Using Gd-Based Collagen I Targeting Probe in Murine Models of Endometriosis

PurposeEndometriosis is a chronic condition characterized by high fibrotic content and affecting about 10% of women during their reproductive years. Yet, no clinically approved agents are available for non-invasive endometriosis detection. The purpose of this study was to investigate the utility of a gadolinium-based collagen type I targeting probe (EP-3533) to non-invasively detect endometriotic lesions using magnetic resonance imaging (MRI). Previously, this probe has been used for detection and staging of fibrotic lesions in the liver, lung, heart, and cancer. In this study we evaluate the potential of EP-3533 for detecting endometriosis in two murine models and compare it with a non-binding isomer (EP-3612).ProceduresFor imaging, we utilized two GFP-expressing murine models of endometriosis (suture model and injection model) injected intravenously with EP3533 or EP-33612. Mice were imaged before and after bolus injection of the probes. The dynamic signal enhancement of MR T1 FLASH images was analyzed, normalized, and quantified, and the relative location of lesions was validated through ex vivo fluorescence imaging. Subsequently, the harvested lesions were stained for collagen, and their gadolinium content was quantified by inductively coupled plasma optical emission spectrometry (ICP-OES).ResultsWe showed that EP-3533 probe increased the signal intensity in T1-weighted images of endometriotic lesions in both models of endometriosis. Such enhancement was not detected in the muscles of the same groups or in endometriotic lesions of mice injected with EP-3612 probe. Consequentially, control tissues had significantly lower gadolinium content, compared to the lesions in experimental groups. Probe accumulation was similar in endometriotic lesions of either model.ConclusionsThis study provides evidence for feasibility of targeting collagen type I in the endometriotic lesions using EP3533 probe. Our future work includes investigation of the utility of this probe for therapeutic delivery in endometriosis to inhibit signaling pathways that cause the disease.

The application of an intraoral banana peel suturing model in surgical training of dental students.

This study investigated the application of an intraoral banana peel suturing model in helping students to acquire intraoral surgical techniques. This is a self-control study conducted from January 2021 to March 2021. An intraoral banana peel suturing model was implemented to provide oral suture experience for undergraduates majoring in stomatology. The sutures students placed in the model were photographed and evaluated blindly by a professional team using an established scoring system. Training scores were recorded before (training 1) and after 2 months of training (training 2). Linear regression was used to examine factors related to the scores. Suturing training was conducted in the School and Hospital of Stomatology at Peking University. A total of eighty-two students in Peking University School and Hospital of Stomatology were in their fourth pre-clinical year and followed a workshop on surgical sutures according to the curriculum. All students who should take this course were included, and the response rate was 100%. The mean training 2 score (23.04±3.83) was higher than the mean training 1 score (13.94±3.15). The training 1 score was not significantly correlated with any of the students' general characteristics. The training 2 score was correlated with the training 1 score and the cumulative duration of practice outside of class. The intraoral banana peel suturing model can be used for suture training, and dental students' suture ability was improved after using the banana peel for suture practice.

ABCB5+ Limbal Epithelial Stem Cells Inhibit Developmental but Promote Inflammatory (Lymph) Angiogenesis While Preventing Corneal Inflammation.

The limbus, the vascularized junction between the cornea and conjunctiva, is thought to function as a barrier against corneal neovascularization. However, the exact mechanisms regulating this remain unknown. In this study, the limbal epithelial stem cell (LESC) marker ABCB5 was used to investigate the role of LESCs in corneal neovascularization. In an ABCB5KO model, a mild but significant increase of limbal lymphatic and blood vascular network complexity was observed in developing mice (4 weeks) but not in adult mice. Conversely, when using a cornea suture model, the WT animals exhibited a mild but significant increase in the number of lymphatic vessel sprouts compared to the ABCB5KO, suggesting a contextual anti-lymphangiogenic effect of ABCB5 on the limbal vasculature during development, but a pro-lymphangiogenic effect under inflammatory challenge in adulthood. In addition, conditioned media from ABCB5-positive cultured human limbal epithelial cells (ABCB5+) stimulated human blood and lymphatic endothelial cell proliferation and migration. Finally, a proteomic analysis demonstrated ABCB5+ cells have a pro(lymph)angiogenic as well as an anti-inflammatory profile. These data suggest a novel dual, context-dependent role of ABCB5+ LESCs, inhibiting developmental but promoting inflammatory (lymph)angiogenesis in adulthood and exerting anti-inflammatory effects. These findings are of high clinical relevance in relation to LESC therapy against blindness.

Gap26 inhibited angiogenesis through the β-catenin-VE-cadherin-VEGFR2-Erk signaling pathway

PurposeTo investigate the effect of connexin 43 (Cx43) on corneal neovascularization and its regulation of VEGFR2 on vascular endothelial cells. MethodsIn vivo, we used mouse corneal suture model to induce corneal neovascularization and discovered the function of gap26 in corneal neovascularization. In vitro, the effect of gap26 on HUVEC was observed by cell proliferation, tube formation and scratch experiments. WB and PCR detected the changes in angiogenic protein and mRNA expression. Knockdown of key mRNA in neovascularization using siRNA confirmed that Cx43 regulates neovascularization through the β-catenin-VE-cadherin-VEGFR2-Erk signaling pathway. ResultsIn vivo, gap26 can reduce mouse corneal neovascularization. In vitro, we show that Cx43 expression is increased in the presence of VEGFA stimulation, and when we use gap26 to inhibit Cx43 can reduce vascular endothelial cell proliferation, tube formation and migration. We found that the expression of pVEGFR2 and pErk increased in response to VEGFA, while they decreased after using gap26. And the expression of β-catenin and VE-cadherin decreased in response to VEGFA, while they increased after using gap26. Furthermore, we found that Cx43 regulates angiogenesis through the β-catenin-VE-cadherin-VEGFR2-Erk pathway. ConclusionsGap26 can downregulate VEGFR2 phosphorylation by stabilizing the expression of β-catenin and VE-cadherin on the cell membrane, thereby inhibiting VEGFA-induced HUVECs proliferation, migration and tube formation and inhibiting corneal neovascularization.