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Lymphedema, a prevalent, multifaceted, and chronic ailment, is mainly managed through physical manipulation and suffers from a lack of specific pharmacological treatments. Secondary lymphedema is mainly caused by impaired lymphatic drainage. Therapeutic lymphangiogenesis is a promising strategy in the treatment of lymphedema. Andrographolide, a natural product from Andrographis paniculata, is unknown whether andrographolide promotes lymphangiogenesis to improve secondary lymphedema. By using the murine tail lymphedema model, we demonstrated that andrographolide can reduce the thickness of subcutaneous tissue in the mice's tail and enhance lymphatic drainage. Moreover, immunofluorescence staining showed that the number of capillary lymphatic vessels in the ANDRO25 group was significantly more than that in the ANDRO50 and Model groups. Near-infrared lymphography images showed that highlighted sciatic lymph nodes could be seen in the ANDRO25 and ANDRO50 groups. In vitro, andrographolide could promote the proliferation and migration of LEC. In conclusion, andrographolide enhanced the recovery of lymphatic vessels, and promoted lymphatic drainage in the murine tail lymphedema model by promoting the proliferation of lymphatic endothelial cells, thereby reducing the symptoms of lymphedema. This suggested andrographolide may be used as a potential therapeutic drug or medical food ingredient to help patients with secondary lymphedema., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: To investigate the findings on lower limb lymphedema using magnetic resonance lymphography (MRL)., Methods: MRL was used to record the lymphatic vessel morphology, distribution of lymphatic vessels, dermal backflow (DBF), and morphology of inguinal lymph nodes in 112 patients (175 affected limbs) with lower limb lymphedema at different clinical stages (according to the International Society of Lymphology staging criteria 2020)., Results: The lymphatic vessel morphology significantly differed at different clinical stages (X 2 =59.306; P = 0.000). ISL stage I is dominated by "scattered beads" and "branch-like" distribution, ISL stage Ⅱ has tree branch or "capillary-like" distribution, and ISL stage Ⅲ primarily has a capillary pattern and contrast agent accumulation in the foot. There were statistically significant differences in the distribution of lymphatic vessels and DBF in different clinical stages. Distribution of the enhanced lymphatic vessels was distal to the knee in ISL stage I, involved areas below the knee joint or the whole limb in ISL stage II, and involved the whole limb in ISL stage III (X 2 =44.591; P = 0.000). With the progression of edema, DBF severity increased (X 2 =76.416; P = 0.000)., Conclusion: MRL revealed the morphology and distribution of lymphatic vessels and detected abnormal inguinal lymph nodes in patients at different stages of lymphedema, which can be used as reference information for surgical treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

Background: Mitral valve (MV) disease including myxomatous degeneration is the most common form of valvular heart disease with an age-dependent frequency. Genetic evidence indicates that mutations of the human transcription factor FOXC1 are associated with MV defects, including MV regurgitation. In this study, we sought to determine whether murine Foxc1 and its closely related factor, Foxc2 , are required in valvular endothelial cells (VECs) for the maintenance of MV leaflets, including VEC junctions and the stratified trilaminar ECM (extracellular matrix)., Methods: Adult mice carrying tamoxifen-inducible, vascular endothelial cell (EC), and lymphatic EC-specific, compound Foxc1;Foxc2 mutations (ie, EC- Foxc -DKO and lymphatic EC- Foxc -DKO mice, respectively) were used to study the function of Foxc1 and Foxc2 in the maintenance of MVs. The EC and lymphatic EC mutations of Foxc1/c2 were induced at 7 to 8 weeks of age by tamoxifen treatment, and abnormalities in the MVs of these mutant mice were assessed via whole-mount immunostaining, immunohistochemistry/RNAscope, Movat pentachrome/Masson Trichrome staining, and Evans blue injection., Results: EC deletions of Foxc1 and Foxc2 in mice resulted in abnormally extended and thicker MVs by causing defects in the regulation of ECM organization with increased proteoglycan and decreased collagen. Notably, reticular adherens junctions were found in VECs of control MV leaflets, and these reticular structures were severely disrupted in EC- Foxc -DKO mice. PROX1 (prospero homeobox protein 1), a key regulator in a subset of VECs on the fibrosa side of MVs, was downregulated in EC- Foxc1/c2 mutant VECs. Furthermore, we determined the precise location of lymphatic vessels in murine MVs, and these lymphatic vessels were aberrantly expanded and dysfunctional in EC- Foxc1/c2 mutant MVs. Lymphatic EC deletion of Foxc1/c2 also resulted in similar structural/ECM abnormalities as seen in EC- Foxc1/c2 mutant MVs., Conclusions: Our results indicate that Foxc1 and Foxc2 are required for maintaining the integrity of the MV, including VEC junctions, ECM organization, and lymphatic vessel formation/function to prevent myxomatous MV degeneration., Competing Interests: None.

Biomimetic tumor microenvironment models bridge the gap between in vitro and in vivo systems and serve as a useful way to address the modeling challenge of how to recreate the cell and system complexity associated with real tissues. Our laboratory has developed an ex vivo rat mesentery culture model, which allows for simultaneous investigation of blood and lymphatic microvascular network remodeling in an intact tissue environment. Given that angiogenesis and lymphangiogenesis are key contributors to the progression of cancer, the objective of this study was to combine tissue and tumor spheroid culture methods to establish a novel ex vivo tumor spheroid-tissue model by verifying its use for evaluating the effects of cancer cell behavior on the local microvascular environment. H1299 or A549 tumor spheroids were formed via hanging drop culture and seeded onto rat mesenteric tissues harvested from adult male Wistar rats. Tissues with transplanted spheroids were cultured in serum-free media for 3 to 5 days. PECAM, NG2, CD11b, and αSMA labeling identified endothelial cells, pericytes, immune cells, and smooth muscle cells, respectively. Time-lapse imaging confirmed cancer cell type specific migration. In addition to increasing PECAM positive capillary sprouting and LYVE-1 positive endothelial cell extensions indicative of lymphangiogenesis, tumor spheroid presence induced the formation of lymphatic/blood vessel connections and the formation of hybrid, mosaic vessels that were characterized by discontinuous LYVE-1 labeling. The results support the application of a novel tumor spheroid microenvironment model for investigating cancer cell-microvascular interactions., (© 2024. The Author(s) under exclusive licence to Biomedical Engineering Society.)

Both lymphatic vessels and macrophages are key factors influencing the inflammatory response. During the inflammatory response, lymphatic vessels undergo dilation and growth, playing a beneficial role in alleviating inflammation by facilitating the drainage of exudate, inflammatory mediators, and leukocytes. Consequently, the promotion of lymphangiogenesis has emerged as a novel therapeutic approach to treating inflammation. Macrophages play a crucial role in promoting lymphangiogenesis by secreting several pro-lymphatic growth factors, including vascular endothelial growth factor (VEGF)-C, and undergoing transdifferentiation into lymphatic endothelial cell progenitors (LECP), which integrate into newly formed lymphatic vessels. Macrophages exhibit heterogeneity and perform diverse functions based on their phenotypes. The regulation of macrophage polarization is crucial in inflammatory responses. Notably, macrophages promote lymphangiogenesis, while lymphatic vessels, in turn, serve as a conduit for macrophages to drain out inflamed tissue and also affect macrophage polarization. Thus, there is an interactive relationship between them. In this review, we discuss current work on the effects of macrophages on lymphangiogenesis as well as lymphatic vessel recruitment of macrophages and regulation of macrophage polarization. Furthermore, we explore the roles of lymphatic vessels and macrophages in various inflammation-related diseases, emphasizing potential therapeutic targets within the context of lymphatic-macrophage interactions., (© 2024 Federation of American Societies for Experimental Biology.)

Objective: To analyze the lympho-vascular space invasion (LVSI) in different molecular subtypes of the cancer genome atlas (TCGA) molecular subtypes of endometrial cancer (EC) and to evaluate the prognostic value of LVSI in EC patients with different molecular subtypes. Methods: A total of 258 patients diagnosed EC undergoing surgery in Peking University People's Hospital from January 2016 to June 2022 were analyzed retrospectively. Among 258 patients, 14 cases were classified as POLE-ultramutated subtype, 43 as high-microsatellite instability (MSI-H) subtype, 155 as copy-number low (CNL) subtype, and 46 as copy-number high (CNH) subtype. Fifty-four patients were positive for LVSI, while 203 tested negative. Results: (1) The incidence of LVSI was found to be highest in the CNH subtype (32.6%,15/46), followed by the MSI-H subtype (27.9%, 12/43), the CNL subtype (16.9%, 26/154), and the POLE-ultramutated subtype (1/14), with statistically significant differences ( χ 2 =7.79, P =0.044). (2) Staging and deep myometrial invasion were higher in the LVSI positive group than those in the LVSI negative group (all P <0.05), except for the POLE-ultramutated subtype. The grade, lymph node metastasis, and the expression of nuclear antigen associated with cell proliferation (Ki-67) were significantly higher in LVSI positive patients than those in LVSI negative EC patients with both MSI-H and CNL subtypes (all P <0.05). In CNL subtypes patients, LVSI was also associated with age, histology subtype,and progesterone receptor (PR; all P <0.05). (3) Of the 257 EC patients, 25 cases recurred during the follow-up period, with a recurrence rate of 9.7% (25/257); among them, the recurrence rate of LVSI positive patients was 22.2% (12/54), which was significantly higher than those with LVSI negative (6.4%, 13/203; χ 2 =12.15, P <0.001). During the follow-up period, none of the 14 patients with POLE-ultramutated had recurrence; among CNL patients, the recurrence rate was 19.2% (5/26) in LVSI positive patients, which was significantly higher than that in LVSI negative ones (5.5%, 7/128; χ 2 =3.94, P =0.047); where as no difference were found in both MSI-H [recurrence rates in LVSI positive and negative patients were 2/12 and 9.7% (3/31), respectively] and CNH subtype [recurrence rates between LVSI positive and negative patients were 5/15 and 9.7% (3/31), respectively] EC patients (both P >0.05). After log-rank test, the 3-year recurrence free survival (RFS) rate were significantly lower in LVSI positive patients from CNL subtype and CNH subtype than those in LVSI negative patients (CNL: 80.8% vs 94.5%; CNH: 66.7% vs 90.3%; both P <0.05). (4) Lymph node metastasis ( HR =6.93, 95% CI : 1.15-41.65; P =0.034) had a significant effect on the 3-year RFS rate of EC patients with MSI-H subtype. Multivariate analysis revealed that PR expression ( HR =0.04, 95% CI : 0.01-0.14; P <0.001) was significantly associated with the 3-year RFS rate of CNL subtype patients. Conclusions: LVSI has the highest positivity rate in CNH subtype, followed by MSI-H subtype, CNL subtype, and the lowest positivity rate in POLE-ultramutated subtype. LVSI is significantly associated with poor prognosis in CNL subtype patients and may affect the prognosis of CNH subtype patients. However, LVSI is not an independent risk factor for recurrence across all four TCGA molecular subtypes.

Background: Lymphatic vessels (LVs) play a crucial role in immune reactions by serving as the principal conduits for immune cells. However, to date, no study has analyzed the morphological changes in the LVs of patients with biliary atresia (BA). In this study, we aimed to determine the morphological changes in the LVs irrigating the liver in patients with BA, elucidate their correlations with the morphology of the portal vein (PV) branches, and discuss their etiopathogenetic significance., Methods: Morphometric analyses of liver biopsy specimens from patients treated between 1986 and 2016 were performed. The parameters measured were as follows: the whole liver area of the specimen, fibrotic area, number of LVs, LVs without patent lumen (designated as Ly0) and PV branches, and diameters of the LVs with patent lumen and the PVs., Results: The numbers of LVs, Ly0, and PV branches per unit area of the whole liver specimen were significantly higher in patients with BA than in control participants with liver disease and those with normal livers. However, no correlation was observed between the fibrotic area and the average diameter of LVs or PVs, and between the fibrotic area and the number of LVs or PV branches. Furthermore, no correlation was observed between the total number of LVs and the number of PV branches., Conclusions: The present study showed a significant increase in the number of total LVs and Ly0, characterized by a high Ly0 to total LVs ratio, suggesting that lymphangiogenesis occurs in the liver of patients with BA., (© 2024. The Author(s).)

Generalized lymphatic anomaly (GLA) and kaposiform lymphangiomatosis (KLA) are rare congenital disorders that arise through anomalous embryogenesis of the lymphatic system. A somatic activating NRAS p.Q61R variant has been recently detected in GLA and KLA tissues, suggesting that the NRAS p.Q61R variant plays an important role in the development of these diseases. To address this role, we studied the effect of the NRAS p.Q61R variant in lymphatic endothelial cells (LECs) on the structure of the lymphatics during embryonic and postnatal lymphangiogenesis applying inducible, LEC-specific NRAS p.Q61R variant in mice. Lox-stop-Lox NrasQ61R mice were crossed with Prox1-CreERT2 mice expressing tamoxifen-inducible Cre recombinase specifically in LECs. Whole-mount immunostaining of embryonic back skin using an antibody against the LEC surface marker VEGFR3 showed considerably greater lymphatic vessel width in LEC-specific NRAS p.Q61R mutant embryos than in littermate controls. These mutant embryos also showed a significant reduction in the number of lymphatic vessel branches. Furthermore, immunofluorescence staining of whole-mount embryonic back skin using an antibody against the LEC-specific nuclear marker Prox1 showed a large increase in the number of LECs in LEC-specific NRAS p.Q61R mutants. In contrast, postnatal induction of the NRAS p.Q61R variant in LECs did not cause abnormal lymphatic vessel morphogenesis. These results suggest that the NRAS p.Q61R variant in LECs plays a role in development of lymphatic anomalies. While this model does not directly reflect the human pathology of GLA and KLA, there are overlapping features, suggesting that further study of this model may help in studying GLA and KLA mechanisms., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Migraines are a type of headache that occur with other neurological symptoms, but the pathophysiology remains unclear. In this issue of the JCI, Nelson-Maney and authors used constitutive and inducible knockouts of the CGRP receptor components, elegantly demonstrating an essential function of CGRP in modulating meningeal lymphatic vessels (MLVs) in migraine. CGRP was shown to induce rearrangement of membrane-bound gap junction proteins in MLVs, resulting in a reduced CSF flux into cervical lymph nodes. The authors also provided evidence of a primary role for CGRP in modulating neuro-immune function. Finally, by showing that blocking CGRP signaling in MLVs attenuated pain behavior associated with acute migraine in rodents, the authors provided a target for pharmacological blockade of CGRP in relation to primary headache disorders.

Lymphatics are involved in the resolution of inflammation and wound healing, but their role in the oral wound healing process after tooth extraction has never been investigated. We therefore sought to evaluate the healing process following the extraction of maxillary molars in two transgenic mouse models: K14-VEGFR3-Ig mice, which lack initial mucosal lymphatic vessels, and K14-VEGFC mice, which have hyperplastic mucosal lymphatics. Maxillary molars were extracted from both transgenic mouse types and their corresponding wild-type (WT) controls. Mucosal and alveolar bone healing were evaluated. A delayed epithelialization and bone regeneration were observed in K14-VEGFR3-Ig mice compared with their WT littermates. The hampered wound closure was accompanied by decreased levels of epidermal growth factor (EGF) and persistent inflammation, characterized by infiltrates of immune cells and elevated levels of pro-inflammatory markers in the wounds. Hyperplastic mucosal lymphatics did not enhance the healing process after tooth extraction in K14-VEGFC mice. The findings indicate that initial mucosal lymphatics play a major role in the initial phase of the oral wound healing process., (© 2024 The Author(s). European Journal of Oral Sciences published by John Wiley & Sons Ltd on behalf of Scandinavian Division of the International Association for Dental Research.)

Pathological diagnosis of breast cancer often includes cases of lymph node metastases without lymphatic or lymphovascular invasion by the primary tumor. In this study, to resolve this discrepancy, we designed a sensitive method to detect lymphatic invasion and correlate it with lymph node metastasis. Elastica van Gieson (EVG) staining and D2-40 immunohistochemistry revealed the abundant distribution of lymphatic vessels around blood vessels in the mammary tissue in close proximity to the elastic fibers around the arteries and veins. Based on the histological location of the blood and lymphatic vessels, we hypothesized that, in breast cancer, perivascular invasion is similar to lymphatic invasion and correlates with the presence of lymph node metastasis. Using EVG staining, perivascular invasion was histologically classified into periarterial invasion (periA), perivenous invasion (periV), and periarterial or perivenous invasion (periA/V). We tested our method and compared it to other methods commonly used for identifying lymphatic invasion in 105 patients with invasive breast carcinoma of no special type (IBC-NST) who received minimal preoperative therapy. The correlation between perivascular invasion and lymph node metastasis in these patients was statistically analyzed, including findings related to lymphatic invasion, such as retractile artifacts and perineural invasion. PeriA, periV, and periA/V showed significant correlations with lymph node metastasis. PeriA/V had high sensitivity and negative predictive value. The odds ratio (OR) for periV was significantly high in the univariate analysis, while the ORs for periA/V, retraction artifacts, and perineural invasion were significantly high in both the univariate and multivariate analyses. In particular, periA/V revealed a strong correlation with lymph node metastasis (OR: 61.8). These findings indicate that the IBC-NST periA/V ratio is a sensitive pointer of lymphatic invasion and could be an independent and reliable indicator of lymph node metastasis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Whether cancer cells metastasize from the primary site to the distant sites via the lymphatic vessels or the blood vessels directly into the circulation is still under intense study. In this review article, we follow the journey of cancer cells metastasizing to the sentinel lymph nodes and beyond to the distant sites. We emphasize cancer heterogeneity and microenvironment as major determinants of cancer metastasis. Multiple molecules have been found to be associated with the complicated process of metastasis. Based on the large sentinel lymph node data, it is reasonable to conclude that cancer cells may metastasize through the blood vessels in some cases but in most cases, they use the sentinel lymph nodes as the major gateway to enter the circulation to distant sites., (© 2024. The Author(s).)

Background: Although there is a large body of literature regarding risk stratification and outcomes for perineural invasion (PNI) in cutaneous squamous cell carcinoma (cSCC), there is a relative paucity of studies exploring the role of lymphovascular invasion (LVI) in cSCC and a lack of clear evidence-based guidelines for how to manage patients with these tumors., Objective: This article is intended to review the available literature regarding LVI in cSCC and formulate evidence-based recommendations for clinical management., Methods and Materials: A literature review was conducted using PubMed to find relevant articles relating to outcomes and management of primary cSCC with LVI., Results: The available literature suggests that LVI is a major risk factor for poor outcomes and increased morbidity and mortality in cSCC., Conclusion: Lymphovascular invasion is a very high-risk feature that should place these tumors in the highest-risk category, and management of these tumors should be similar to that of squamous cell carcinoma with PNI., (Copyright © 2024 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. All rights reserved.)

Most cancers and in particular carcinomas metastasise via the lymphatics to draining lymph nodes from where they can potentially achieve systemic dissemination by invasion of high endothelial blood venules (HEVs) in the paracortex [1, 2]. Currently however, the mechanisms by which tumours invade and migrate within the lymphatics are incompletely understood, although it seems likely they exploit at least some of the normal physiological mechanisms used by immune cells to access lymphatic capillaries and traffic to draining lymph nodes in the course of immune surveillance, immune modulation and the resolution of inflammation [3, 4]. Typically these include directional guidance via chemotaxis, haptotaxis and durotaxis, adhesion to the vessel surface via receptors including integrins, and junctional re-modelling by MMPs (Matrix MetalloProteinases) and ADAMs (A Disintegrin And Metalloproteinases) [5-7]. This short review focusses on a newly emerging mechanism for lymphatic entry that involves the large polysaccharide hyaluronan (HA) and its key lymphatic and immune cell receptors respectively LYVE-1 (Lymphatic Vessel Endothelial receptor) and CD44, and outlines recent work which indicates this axis may also be used by some tumours to aid nodal metastasis., (© 2023. The Author(s).)

Physiological calcification of soft tissues is a common occurrence in aging and various acquired and inherited disorders. ABCC6 sequence variations cause the calcification phenotype of pseudoxanthoma elasticum (PXE) as well as some cases of generalized arterial calcification of infancy, which is otherwise caused by defective ENPP1. ABCC6 is primarily expressed in the liver, which has given the impression that the liver is central to the pathophysiology of PXE/generalized arterial calcification of infancy. The emergence of inflammation as a contributor to the calcification in PXE suggested that peripheral tissues play a larger role than expected. In this study, we investigated whether bone marrow-derived ABCC6 contributes to the calcification in PXE. In Abcc6 ‒/‒ mice, we observed prevalent mineralization in several lymph nodes and surrounding connective tissues and an extensive network of lymphatic vessels within vibrissae, a calcified tissue in Abcc6 ‒/‒ mice. Furthermore, we found evidence of lymphangiogenesis in patients with PXE and mouse skin, suggesting an inflammatory process. Finally, restoring wild-type bone marrow in Abcc6 ‒/‒ mice produced a significant reduction of calcification, suggesting that the liver alone is not sufficient to fully inhibit mineralization. With evidence that ABCC6 is expressed in lymphocytes, we suggest that the adaptative immune system and inflammation largely contribute to the calcification in PXE/generalized arterial calcification of infancy., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: In 2016, the ESMO-ESGO-ESTRO consensus included LVSI (Lymph-vascular space invasion, LVSI) status as a risk stratification factor for stage I endometrioid endometrial cancer (EEC) patients and as one of the indications for adjuvant therapy. Furthermore, LVSI is included in the new FIGO staging of endometrial cancer (EC) in 2023. However, the data contribution of the Chinese population in this regard is limited. The present study aimed to further comfirm the influence of LVSI on the prognosis of early-stage low-grade EEC in a fifteen-year retrospective Chinese cohort study., Methods: This retrospective analysis cohort included 702 EEC patients who underwent TAH/BSO surgery, total abdominal hysterectomy, bilateral salpingooophorectomy in Peking University People's Hospital from 2006 to 2020. Patients were stratified based on LVSI expression status as: LVSI negative group and LVSI positive group. Clinical outcome measures related to LVSI, assessed with a univariate and multivariate Cox proportional hazards regression model., Results: 702 EEC patients with stage I and grade 1-2 were analyzed. 58 patients (8.3%) were LVSI-positive and 14 patients (2.0%) was relapse. Recurrence rates in LVSI-negative and LVSI-positive were 1.6% and 6.9%, respectively. 5-year disease-free survival (DFS) rate in LVSI-negative and LVSI-positive were 98.4% and 93.1%, respectively. These rates for 5-year overall (OS) survival in LVSI-negative were 98.9% while it was 94.8% in LVSI-positive. Multivariate analysis showed that LVSI is an independent risk factor for 5-year DFS (HR = 4.60, p = 0.010). LVSI has a similar result for 5-year OS(HR = 4.39, p = 0.028)., Conclusions: LVSI is an independent predictor of relapse and poor prognosis in early-stage low-grade endometrioid endometrial cancer in the Chinese cohort., (© 2024. The Author(s).)

The subareolar Sappey's plexus was studied using color lymphography and immunohistochemical methods with a panel of antibodies to podoplanin, smooth muscle actin, low molecular weight cytokeratin AE1/AE3, and GATA3 on archival material obtained during radical mastectomies and sectoral resections with lymph node dissection from 86 patients diagnosed with non-special type breast cancer. At the macro- and microscopic levels, the connection between the subareolar lymphatic plexus and the lymphatic system of the breast parenchyma has been demonstrated. In triple negative breast cancer with metastases to the axillary lymph nodes, the involvement of subareolar lymphatic plexus into lymphogenous metastasis to the lymph nodes of the axillary lymphatic collector was shown., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature.)

Objective: We demonstrate the surgical technique of removing the sentinel lymph nodes with its afferent lymphatic vessels attached to the hysterectomy specimen., Design: Stepwise demonstration of the technique with narrated video footage., Setting: Sentinel lymph node sampling has been established as an acceptable staging method in endometrial cancer cases. 1 Lymphatic anatomy has been described according to three consistent channels for endometrial cancer dissemination: (1) an upper paracervical pathway draining external or obturator lymph nodes; (2) a lower pathway draining internal iliac lymph nodes; and (3) the infundibulo-pelvic pathway with a course along the broad ligament. 2 A study in patients with cervical cancer identified tumor cells in the afferent lymphatic vessels of the upper pathway, even when the corresponding sentinel node was negative (3/20 patients). 3 This could be an important prognostic factor in patients with cervical cancer. Since the typical position of sentinel nodes is the same in both endometrial and cervical cancers, we aimed to assess the feasibility of removing 'en bloc' the sentinel node with its afferent lymphatic vessels, and the uterus. 4 INTERVENTIONS: The Da Vinci Xi surgical system was used. Indocyanine green was injected cervically, the pelvic surgical spaces were developed, and the sentinel lymph nodes, along with the afferent lymphatic vessels, were identified using the Firefly infrared camera. The lymphovascular tissue was mobilized and separated from the uterine artery, which was skeletonized and ligated. Colpotomy was performed and the specimen was retrieved vaginally., Discussion: Emerging evidence regarding diagnosis, characterization, and treatment of endometrial cancer has introduced a new era, based on minimally invasive techniques for staging through sentinel lymph node biopsy, molecular classification, and personalized treatment algorithms that include immune checkpoint inhibitors and targeted therapies. 5 Lymph node staging is one of the most significant prognostic factors in endometrial cancer patients and is a guide for adjuvant treatment. Sentinel lymph node biopsy is not inferior to conventional lymphadenectomy and is in fact a better way of identifying low-volume cancer through the use of ultrastaging, as part of the sentinel node algorithm. 6 The dissection technique described in this video could offer an improvement in the staging of endometrial cancer, ensuring that the true sentinel lymph node is identified and that potential cancer cells inside the afferent lymphatic vessels are also excised. Therefore, it could be utilized as a more accurate way of planning adjuvant treatment and consequently improving recurrence and survival; however more studies are needed to further evaluate the feasibility and sensitivity of identifying disease in the afferent lymphatic vessels., Conclusion: This novel surgical technique emphasizes the importance of anatomical knowledge and offers inspiration for studies with potential clinical benefit that should follow., (© 2024. Society of Surgical Oncology.)

Purpose: To investigate the prognostic significance of lymphovascular invasion in invasive breast cancer and the value of using specific vascular endothelial markers to further classify lymphovascular invasion., Methods: We collected 2124 patients with invasive breast cancer who were hospitalized at the First Hospital of Dalian Medical University from 2012 to 2020. Statistical methods were used to investigate the relationship between lymphovascular invasion and clinicopathological characteristics of breast cancer, and the correlation between lymphovascular invasion on overall survival (OS) and disease-free survival (DFS) of various categories of breast cancers. Immunohistochemical staining of breast cancer samples containing lymphovascular invasion using specific vascular endothelial markers D2-40 and CD34 was used to classify lymphovascular invasion and to investigate the relationship between lymphovascular invasion and breast cancer progression., Results: There was a high correlation between lymphovascular invasion and T stage, N stage and nerve invasion. Survival analyses showed that patients with lymphovascular invasion, especially luminal B, triple-negative, and Her-2 overexpression breast cancer patients, had poorer OS and DFS prognosis, and that lymphovascular invasion was an independent prognostic factor affecting OS and DFS in breast cancer. The immunohistochemical staining results showed that positive D2-40 staining of lymphovascular invasion was linked to the N stage and localized recurrence of breast cancer., Conclusion: Lymphovascular invasion is associated with aggressive clinicopathological features and is an independent poor prognostic factor in invasive breast cancer. Breast cancer localized recurrence rate and lymph node metastases are influenced by lymphatic vessel invasion. Immunohistochemical techniques should be added to the routine diagnosis of lymphovascular invasion., (© 2024. The Author(s).)

The integrity of the lymphatic system is critical for preventing the dissemination of tumor cells, such as melanoma, to distant parts of the body. IFN-γ is well studied as a negative regulator for lymphangiogenesis, which is strongly associated with cancer metastasis. However, the exact mechanisms underlying this process remain unclear. In the present study, we investigated whether IFN-γ signaling in lymphatic endothelial cells (LECs) affects tumor cell dissemination by regulating the barrier function of tumor-associated lymphatic vessels. Using LEC-specific IFN-γ receptor (IFN-γR) knockout mice, we found that the loss of IFN-γR in LECs increased the dissemination of melanoma cells into the draining lymph nodes. Notably, IFN-γ signaling in LECs inhibited trans-lymphatic endothelial cell migration of melanoma cells, indicating its regulation of lymphatic barrier function. Further investigations revealed that IFN-γ upregulated the expression of the tight junction protein Claudin-3 in LECs, while knockdown of Claudin-3 in LECs abolished IFN-γ-induced inhibition of trans-lymphatic endothelial migration activity. Mechanistically, IFN-γ inhibits AMPK signaling activation, which is involved in the regulation of fatty acid metabolism. Modulating fatty acid metabolism and AMPK activation in LECs also affected the lymphatic dissemination of melanoma cells, further confirming that this process is involved in IFN-γ-induced regulation of lymphatic barrier function. These results provide novel insights into how IFN-γ modulates tight junctions in LECs, inhibiting the dissemination of melanoma cells via the lymphatic vessels., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

While conventional cancer modalities, such as chemotherapy and radiotherapy, act through direct killing of tumor cells, cancer immunotherapy elicits potent anti-tumor immune responses thereby eliminating tumors. Nevertheless, promising outcomes have not been reported in patients with glioblastoma (GBM) likely due to the immune privileged status of the central nervous system and immunosuppressive micro-environment within GBM. In the past years, several exciting findings, such as the re-discovery of meningeal lymphatic vessels (MLVs), three-dimensional anatomical reconstruction of MLV networks, and the demonstration of the promotion of GBM immunosurveillance by lymphatic drainage enhancement, have revealed an intricate communication between the nervous and immune systems, and brought hope for the development of new GBM treatment. Based on conceptual framework of the updated cancer-immunity (CI) cycle, here we focus on GBM antigen drainage and immune activation, the early events in driving the CI cycle. We also discuss the implications of these findings for developing new therapeutic approaches in tackling fatal GBM in the future., (© 2024. The Author(s).)

Background: Lymphedema is chronic limb swelling resulting from lymphatic dysfunction. It affects an estimated five million Americans. There is no cure for this disease. Assessing lymphatic growth is essential in developing novel therapeutics. Intravital microscopy (IVM) is a powerful imaging tool for investigating various biological processes in live animals. Tissue nanotransfection technology (TNT) facilitates a direct, transcutaneous nonviral vector gene delivery using a chip with nanochannel poration in a rapid (<100 ms) focused electric field. TNT was used in this study to deliver the genetic cargo in the murine tail lymphedema to assess the lymphangiogenesis. The purpose of this study is to experimentally evaluate the applicability of IVM to visualize and quantify lymphatics in the live mice model. Methods and Results: The murine tail model of lymphedema was utilized. TNT was applied to the murine tail (day 0) directly at the surgical site with genetic cargo loaded into the TNT reservoir: TNT pCMV6 group receives pCMV6 (expression vector backbone alone) ( n = 6); TNT Prox1 group receives pCMV6- Prox1 ( n = 6). Lymphatic vessels (fluorescein isothiocyanate [FITC]-dextran stained) and lymphatic branch points (indicating lymphangiogenesis) were analyzed with the confocal/multiphoton microscope. The experimental group TNT Prox1 exhibited reduced postsurgical tail lymphedema and increased lymphatic distribution compared to TNT pCMV6 group. More lymphatic branching points (>3-fold) were observed at the TNT site in TNT Prox1 group. Conclusions: This study demonstrates a novel, powerful imaging tool for investigating lymphatic vessels in live murine tail model of lymphedema. IVM can be utilized for functional assessment of lymphatics and visualization of lymphangiogenesis following gene-based therapy.

Anatomical and functional aspects of the lymphatic drainage of the uterine corpus in endometrial cancer are demonstrated. Main lymphatic pathway runs along the upper pelvic pathway from the uterine artery first line to the medial external iliac nodes, followed by the lateral external and common iliac node basin. The second important pathway runs along the ovarian vessels directly to the paraaortic nodes. Pathways may visualized best by injection of indocyanine green (ICG) into the uterus. In contrast to the upper pelvic pathway visualized by cervical injection, the paraaortic drainage can only be marked by corporal injection. Lymphatic drainage works downstream (peripheral to central, with respect to vascular valves) only. Clinically, pelvic sentinel node excision replaced systematic lymphadenectomy for diagnostic purposes and even paraaortic node staging can be omitted in most of pelvic node negative patients. For therapeutic purposes compartmental resection of the uterus together with its lymphovascular system and first line nodes "en bloc" could be an option as performed in peritoneal mesometrial resection/targeted compartmental lymphadenctomy (PMMR/TCL)., Competing Interests: Declaration of competing interest Rainer Kimmig declares potential conflicts of interest: presentations, advisory boards, proctorings, travel fees for Intuitive Surgical, Medtronic, Medicaroid, Cambridge Medical Robotics, Avatera, Cava Robotics and Active Surgical. Fabinshi Thangarajah and Paul Buderath declare no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The diatom test has been used by forensic pathologist as standard for drowning, but the occurrence of false-positive results (presence of diatoms found in the tissues of subjects who died from causes other than drowning) draws criticism regarding the specificity of the test. Diatoms within food or water can be ingested through the gastrointestinal tract. However, the mechanisms of how the diatoms reach distant organs such as the lung, liver, and kidney have not been studied. In this article, we simulated the process of diatoms entering the gastrointestinal tract using gastric lavage on experimental rabbits. Diatoms are detected in lymph from a lymphatic vessel at the root of the mesentery, portal vein blood, aortic blood, lung, liver, and kidney samples in the gavage group. Of diatoms, 76.24% were the centric diatom, 99.86% of diatoms have a maximum size of less than 50 µm, and most of diatoms concentrate in the lung. Our study provided the evidence supporting the theory that the diatoms could pass through the gastrointestinal barrier and reach the rabbits' other internal organs. The diatoms could reach internal organs through the portal vein and lymphatic vessel at the root of the mesentery. This provides us new insight into our understanding of false-positive diatom test in forensic pathology., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Objective: The pre-collecting and collecting lymph vessels have smooth muscle cells, and sufficient perfusion is vital to maintain their function. Although the vasa vasorum of the collecting lymph vessels (VVCL) have been histologically investigated, little is known about their physiology. This study aimed to investigate the relationship between morphology and blood flow of the VVCL in lymphoedematous limbs., Methods: Medical records of lower extremity lymphoedema patients who underwent video capillaroscopy observation during supermicrosurgical lymphaticovenous anastomosis (LVA) surgery were reviewed. The collecting lymph vessels, dissected for LVA, were examined under video capillaroscopy (GOKO Bscan-ZD, GOKO Imaging Devices Co., Japan) with a magnification of 175x and 620x. Blood flow velocity of the VVCL was calculated by measuring the red blood cell movement using software (GOKO-VIP ver. 1.0.0.4, GOKO Imaging Devices Co., Japan). Based on the video capillaroscopy findings, the VVCL were grouped according to their morphology; the VVCL morphology types and blood flow velocity were then compared according to the lymphosclerosis severity grade., Results: Sixty-seven lymph vessels in 20 lower extremity lymphoedema patients were evaluated, including s0 in 19 (28.4%), s1 in 34 (50.7%), s2 in 10 (14.9%), and s3 in four (6.0%) lymph vessels. The VVCLs were grouped into four types: type 1 (n = 4), type 2 (n = 37), type 3 (n = 19), and type 4 (n = 7). Blood flow velocity of the VVCL ranged 0 - 189.3 μm/sec (average 26.40 μm/sec). There were statistically significant differences in VVCL morphology (p < .001) and blood flow velocity (p < .001) according to lymphosclerotic severity., Conclusion: Vasa vasorum of the collecting lymph vessels could be grouped into four types with different characteristics. Morphological and physiological changes of the VVCL were related to sclerotic changes of the collecting lymph vessels., (Copyright © 2023 European Society for Vascular Surgery. Published by Elsevier B.V. All rights reserved.)

Recently developed antimigraine therapeutics targeting calcitonin gene-related peptide (CGRP) signaling are effective, though their sites of activity remain elusive. Notably, the lymphatic vasculature is responsive to CGRP signaling, but whether meningeal lymphatic vessels (MLVs) contribute to migraine pathophysiology is unknown. Mice with lymphatic vasculature deficient in the CGRP receptor (CalcrliLEC mice) treated with nitroglycerin-mediated (NTG-mediated) chronic migraine exhibit reduced pain and light avoidance compared with NTG-treated littermate controls. Gene expression profiles of lymphatic endothelial cells (LECs) isolated from the meninges of Rpl22HA/+;Lyve1Cre RiboTag mice treated with NTG revealed increased MLV-immune interactions compared with cells from untreated mice. Interestingly, the relative abundance of mucosal vascular addressin cell adhesion molecule 1-interacting (MAdCAM1-interacting) CD4+ T cells was increased in the deep cervical lymph nodes of NTG-treated control mice but not in NTG-treated CalcrliLEC mice. Treatment of cultured hLECs with CGRP peptide in vitro induced vascular endothelial-cadherin (VE-cadherin) rearrangement and reduced functional permeability. Likewise, intra cisterna magna injection of CGRP caused rearrangement of VE-cadherin, decreased MLV uptake of cerebrospinal fluid (CSF), and impaired CSF drainage in control mice but not in CalcrliLEC mice. Collectively, these findings reveal a previously unrecognized role for lymphatics in chronic migraine, whereby CGRP signaling primes MLV-immune interactions and reduces CSF efflux.

Competing Interests: Disclosures None.

Significance Statement: The renal lymphatic vasculature and the lymphatic endothelial cells that make up this network play important immunomodulatory roles during inflammation. How lymphatics respond to AKI may affect AKI outcomes. The authors used single-cell RNA sequencing to characterize mouse renal lymphatic endothelial cells in quiescent and cisplatin-injured kidneys. Lymphatic endothelial cell gene expression changes were confirmed in ischemia-reperfusion injury and in cultured lymphatic endothelial cells, validating renal lymphatic endothelial cells single-cell RNA sequencing data. This study is the first to describe renal lymphatic endothelial cell heterogeneity and uncovers molecular pathways demonstrating lymphatic endothelial cells regulate the local immune response to AKI. These findings provide insights into previously unidentified molecular pathways for lymphatic endothelial cells and roles that may serve as potential therapeutic targets in limiting the progression of AKI., Background: The inflammatory response to AKI likely dictates future kidney health. Lymphatic vessels are responsible for maintaining tissue homeostasis through transport and immunomodulatory roles. Owing to the relative sparsity of lymphatic endothelial cells in the kidney, past sequencing efforts have not characterized these cells and their response to AKI., Methods: Here, we characterized murine renal lymphatic endothelial cell subpopulations by single-cell RNA sequencing and investigated their changes in cisplatin AKI 72 hours postinjury. Data were processed using the Seurat package. We validated our findings by quantitative PCR in lymphatic endothelial cells isolated from both cisplatin-injured and ischemia-reperfusion injury, by immunofluorescence, and confirmation in in vitro human lymphatic endothelial cells., Results: We have identified renal lymphatic endothelial cells and their lymphatic vascular roles that have yet to be characterized in previous studies. We report unique gene changes mapped across control and cisplatin-injured conditions. After AKI, renal lymphatic endothelial cells alter genes involved in endothelial cell apoptosis and vasculogenic processes as well as immunoregulatory signaling and metabolism. Differences between injury models were also identified with renal lymphatic endothelial cells further demonstrating changed gene expression between cisplatin and ischemia-reperfusion injury models, indicating the renal lymphatic endothelial cell response is both specific to where they lie in the lymphatic vasculature and the kidney injury type., Conclusions: In this study, we uncover lymphatic vessel structural features of captured populations and injury-induced genetic changes. We further determine that lymphatic endothelial cell gene expression is altered between injury models. How lymphatic endothelial cells respond to AKI may therefore be key in regulating future kidney disease progression., (Copyright © 2024 by the American Society of Nephrology.)

Objectives: This study aimed to investigate the role of blood and lymphatic microvascular density in the progression of oral squamous cell carcinoma (OSCC)., Materials and Methods: The sample was composed of 54 cases of OSCC. The immunoexpression to anti-alpha-smooth muscle actin (α-SMA) and to anti-endoglin (CD105) was used to determine the microvessel density (MVD); anti-podoplanin (D2-40) was used to assess the lymphatic vessel density (LVD); vascular endothelial growth factor (VEGF) was evaluated in malignant cells. The histological differentiation, the worst pattern of invasion (WPOI), tumour thickness and tumour budding (TB) intensity were assessed using haematoxylin-eosin and anti-pan-cytokeratin (AE1/AE3). Patients' age and sex, TNM classification and follow-up time were collected from the medical records., Results: MVD markers presented a similar pattern of expression in blood vessels. However, only α-SMA + MVD was significantly higher among women and in tumours ≤4 cm. LVD was lower in tumours with lymph node metastasis. Regarding the histological parameters, high TB intensity was associated with histological differentiation, advanced clinical stage, greater tumour thickness and reduced disease-free survival. No difference was found in VEGF., Conclusions: The decrease in OSCC LVD could be related to pathological node involvement, whereas high TB intensity could indicate OSCC progression and worse patient outcomes., (© 2023 Wiley Periodicals LLC.)

Objective: To investigate the impact of lymph-vascular space invasion (LVSI) status on the prognosis of endometrial cancer (EC) according to a three-tiered scoring system for LVSI., Methods: PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), International Clinical Trials Registry Platform (ICTRP), and Clinical Trials.gov were searched from inception to September 1st, 2023. The analysis was conducted using STATA 16.0., Results: A total of 9 studies with 4456 EC patients were included in the analysis. No LVSI was found in 72% of EC patients (95% CI 0.65-0.79), while focal and substantial LVSI were present in 16% (95% CI 0.11-0.21) and 13% (95% CI 0.08-018) of patients, respectively. Compared to the no LVSI group, the focal and substantial LVSI groups had poorer overall survival (for focal LVSI: HR 1.33, 95% CI 1.02-1.74; for substantial LVSI: HR 2.51, 95% CI 1.61-3.90), poorer disease-free survival (for substantial LVSI: HR 2.86, 95% CI 1.21-6.77), and an increased risk of recurrence, including pelvic recurrence (for focal LVSI: HR 2.05, 95% CI 1.03-4.07; for substantial LVSI: HR 6.06, 95% CI 3.31-11.08), distant recurrence (for focal LVSI: HR 2.04, 95% CI 1.42-2.92; for substantial LVSI: HR 3.36, 95% CI 2.35-4.793), and lymph node involvement (for focal LVSI: OR 3.52, 95% CI 1.339.34; for substantial LVSI: OR 5.42, 95% CI 2.78-10.58). Substantial LVSI was more prone to pelvic recurrence (HR 1.82, 95% CI 1.05-3.15) and distant recurrence (HR 2.21, 95% CI 1.48-3.28) than focal LVSI., Conclusions: EC patients with focal and substantial LVSI had poorer survival, recurrence, and a higher incidence of lymph node metastasis than patients without LVSI. The substantial LVSI group was associated with even worse prognosis than the focal LVSI group. The three-tiered LVSI scoring system might effectively predict the prognosis of EC and guide clinical decision-making., Protocol Registration: CRD 42023451793., Competing Interests: Declaration of competing interest The author declares no conflict of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objectives: To assess the prognostic ability of lymphovascular invasion (LVI) in upper tract urothelial carcinoma (UTUC) as a predictor of overall survival (OS) using a large North American cohort., Patients and Methods: Our cohort included 5940 patients with clinical M0 UTUC who underwent a radical nephroureterectomy (RNU), between 2010 and 2016, within the National Cancer Database. The main variable of interest was LVI status, and its interaction with pathological nodal (pN) status. Kaplan-Meier curves were used to depict the OS also stratifying patients on LVI status. Cox regression analysis tested the impact of LVI status on OS after accounting for the available covariates., Results: The median (interquartile range [IQR]) age at diagnosis was 71 (63-78) years and most patients had pathological T1 stage disease (48.6%). Nodal status was pN0, pN1 and pNx in 45.8%, 6.3% and 47.9%, respectively. Overall, 22.1% had LVI. The median (IQR) follow-up time was 32.6 (16.0-53.3) months. At the 5-year postoperative follow-up, the estimated OS rate was 28% in patients with LVI vs 66% in those without LVI (P < 0.001). When patients were stratified based on nodal status those rates were 32% vs 68% in pN0 patients (P < 0.001), 23% vs 30% in pN1 patients (P = 0.8), and 28% vs 65% in pNx patients (P < 0.001). On multivariable analysis, the presence of LVI was associated with less favourable OS (hazard ratio 1.79, 95% confidence interval 1.60-1.99; P < 0.001)., Conclusion: Our study assessed the impact of LVI on OS in patients with UTUC in a large North American nationwide cohort. Our series, as the largest to date, indicate that LVI is associated with less favourable survival outcomes in patients with UTUC after RNU, and this variable could be used in counselling patients about their prognosis and might be a useful tool for future trials to risk-stratify patients., (© 2023 BJU International.)

The complex interplay between malignant cells and the cellular and molecular components of the tumor stroma is a key aspect of cancer growth and development. These tumor-host interactions are often affected by soluble bioactive molecules such as proteoglycans. Decorin, an archetypical small leucine-rich proteoglycan primarily expressed by stromal cells, affects cancer growth in its soluble form by interacting with several receptor tyrosine kinases (RTK). Overall, decorin leads to a context-dependent and protracted cessation of oncogenic RTK activity by attenuating their ability to drive a prosurvival program and to sustain a proangiogenic network. Through an unbiased transcriptomic analysis using deep RNAseq, we identified that decorin down-regulated a cluster of tumor-associated genes involved in lymphatic vessel (LV) development when systemically delivered to mice harboring breast carcinoma allografts. We found that Lyve1 and Podoplanin, two established markers of LVs, were markedly suppressed at both the mRNA and protein levels, and this suppression correlated with a significant reduction in tumor LVs. We further identified that soluble decorin, but not its homologous proteoglycan biglycan, inhibited LV sprouting in an ex vivo 3D model of lymphangiogenesis. Mechanistically, we found that decorin interacted with vascular endothelial growth factor receptor 3 (VEGFR3), the main lymphatic RTK, and its activity was required for the decorin-mediated block of lymphangiogenesis. Finally, we identified that Lyve1 was in part degraded via decorin-evoked autophagy in a nutrient- and energy-independent manner. These findings implicate decorin as a biological factor with antilymphangiogenic activity and provide a potential therapeutic agent for curtailing breast cancer growth and metastasis., Competing Interests: Competing interests statement:The authors declare no competing interest.

Lymphedema has become a global health issue following the growing number of cancer surgeries. Curative or supportive therapeutics have long been awaited for this refractory condition. Transcription factor GATA2 is crucial in lymphatic development and maintenance, as GATA2 haploinsufficient disease often manifests as lymphedema. We recently demonstrated that Gata2 heterozygous deficient mice displayed delayed lymphatic recanalization upon lymph node resection. However, whether GATA2 contributes to lymphatic regeneration by functioning in the damaged lymph vessels' microenvironment remains explored. In this study, our integrated analysis demonstrated that dermal collagen fibers were more densely accumulated in the Gata2 heterozygous deficient mice. The collagen metabolism-related transcriptome was perturbed, and collagen matrix contractile activity was aberrantly increased in Gata2 heterozygous embryonic fibroblasts. Notably, soluble collagen placement ameliorated delayed lymphatic recanalization, presumably by modulating the stiffness of the extracellular matrix around the resection site of Gata2 heterozygous deficient mice. Our results provide valuable insights into mechanisms underlying GATA2-haploinsufficiency-mediated lymphedema and shed light on potential therapeutic avenues for this intractable disease., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Heterotopic ossification (HO) is a challenging condition that occurs after musculoskeletal injury and is characterized by the formation of bone in non-skeletal tissues. While the effect of HO on blood vessels is well established, little is known about its impact on lymphatic vessels. Here, we use a mouse model of traumatic HO to investigate the relationship between HO and lymphatic vessels. We show that injury triggers lymphangiogenesis at the injury site, which is associated with elevated vascular endothelial growth factor C (VEGF-C) levels. Through single-cell transcriptomic analyses, we identify mesenchymal progenitor cells and tenocytes as sources of Vegfc. We demonstrate by lineage tracing that Vegfc-expressing cells undergo osteochondral differentiation and contribute to the formation of HO. Last, we show that Vegfc haploinsufficiency results in a nearly 50% reduction in lymphangiogenesis and HO formation. These findings shed light on the complex mechanisms underlying HO formation and its impact on lymphatic vessels., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Tumor invasion into the lymphatic vasculature represents a critical step during malignant progression of epithelial cancers. In this issue of Cancer Cell, Zheng et al. unravel how cancer-associated fibroblasts interact with lymphatic endothelial cells and the extracellular matrix to promote lymphatic tumor invasion and suggest that these processes could be treatment targets., Competing Interests: Declaration of interests RKJ received consultant fees from Cur, DynamiCure, Elpis, Innocoll, Merck, SPARC, and SynDevRx; owns equity in Accurius, Enlight, and SynDevRx; served on the Board of Trustees of Tekla Healthcare Investors, Tekla Life Sciences Investors, Tekla Healthcare Opportunities Fund, and Tekla World Healthcare Fund; and received research grants from Boehringer Ingelheim and Sanofi. BW holds equity in Meliodys Medical. No reagents or funding from these organizations were used in this study., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Lung cancer is a deeply malignant tumor with high incidence and mortality. Despite the rapid development of diagnosis and treatment technology, abundant patients with lung cancer are still inevitably faced with recurrence and metastasis, contributing to death. Lymphatic metastasis is the first step of distant metastasis and an important prognostic indicator of non-small cell lung cancer. Tumor-induced lymphangiogenesis is involved in the construction of the tumor microenvironment, except promoting malignant proliferation and metastasis of tumor cells, it also plays a crucial role in individual response to treatment, especially immunotherapy. Thus, this article reviews the current research status of lymphatic metastasis in non-small cell lung cancer, in order to provide some insights for the basic research and clinical and translational application in this field., (© 2024. The Author(s).)

Lymphedema, resulting from impaired lymphatic drainage, causes inflammation, fibrosis and tissue damage leading to symptoms such as limb swelling and restricted mobility. Despite various treatments under exploration, no standard effective therapy exists. Here a novel technique using the pyro-drive jet injection (PJI) was used to create artificial clefts between collagen fibers, which facilitated the removal of excess interstitial fluid. The PJI was used to deliver a mixture of lactated Ringer's solution and air into the tail of animals with secondary skin edema. Edema levels were assessed using micro-CT scanning. Histopathological changes and neovascularization were evaluated on the injury-induced regenerative tissue. Regarding tissue remodeling, we focused on connective tissue growth factor (CTGF) and vascular endothelial growth factor (VEGF)-C. PJI markedly diminished soft tissue volume in the experimental lymphedema animals compared to the non-injected counterparts. The PJI groups exhibited a significantly reduced proportion of inflammatory granulation tissue and an enhanced density of lymphatic vessels and α-smooth muscle actin (αSMA)-positive small vessels in the fibrous granulation tissue compared to the controls. In addition, PJI curtailed the prevalence of CTGF- and VEGF-C-positive cells in regenerative tissue. In a lymphedema animal model, PJI notably ameliorated interstitial edema, promoted lymphatic vessel growth, and bolstered αSMA-positive capillaries in fibrous granulation tissue. PJI's minimal tissue impact post-lymph node dissection indicates significant potential as an early, standard preventative measure. Easily applied in general clinics without requiring specialized training, it offers a cost-effective and highly versatile solution to the management of lymphedema., (© 2024. The Author(s) under exclusive licence to Japan Human Cell Society.)

Background:  This study assesses associations between bioimpedance spectroscopy (BIS) and magnetic resonance lymphangiography (MRL) in the staging and assessment of lymphedema., Methods:  Adults who received MRL and BIS between 2020 and 2022 were included. We collected fluid, fat, and lymphedema severity ratings, and measured fluid stripe thickness, subcutaneous fat width, and lymphatic diameter on MRL. BIS lymphedema index (L-Dex) scores were collected from patient charts. We assessed sensitivity and specificity of L-Dex scores to detect MRL-identified lymphedema, and examined associations between L-Dex scores and MRL imaging measures., Results:  Forty-eight limbs across 40 patients were included. L-Dex scores had 72.5% sensitivity and 87.5% specificity for detecting MRL-defined lymphedema, with a 96.7% estimated positive predictive value and 38.9% negative predictive value. L-Dex scores were associated with MRL fluid and fat content scores ( p ≤ 0.05), and lymphedema severity ( p  = 0.01), with better discrimination between fluid than fat content levels on pairwise analysis, and poor discrimination between adjacent severity levels. L-Dex scores were correlated with distal and proximal limb fluid stripe thickness (distal: rho = 0.57, p  < 0.01; proximal: rho = 0.58, p  < 0.01), partially correlated with distal subcutaneous fat thickness when accounting for body mass index (rho = 0.34, p  = 0.02), and were not correlated with lymphatic diameter ( p  = 0.25)., Conclusion:  L-Dex scores have high sensitivity, specificity, and positive predictive value for the identification of MRL-detected lymphedema. L-Dex has difficulty distinguishing between adjacent severity levels of lymphedema and a high false negative rate, explained in part by reduced discrimination between levels of fat accumulation., Competing Interests: None declared., (Thieme. All rights reserved.)

Aim: We aim to identify the specific CD4 + T-cell subtype influenced by brain-to-CLN signaling and explore their role during the acute phase of traumatic brain injury (TBI)., Method: Cervical lymphadenectomy or cervical afferent lymphatic ligation was performed before TBI. Cytokine array and western blot were used to detect cytokines, while the motor function was assessed using mNss and rotarod test. CD4 + T-cell subtypes in blood, brain, and CLNs were analyzed with Cytometry by time-of-flight analysis (CyTOF) or fluorescence-activated cell sorting (FACS). Brain edema and volume changes were measured by 9.4T MRI. Neuronal apoptosis was evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining., Results: Cervical lymphadenectomy and ligation of cervical lymphatic vessels resulted in a decreased infiltration of CD4 + T cells, specifically CD11b-positive CD4 + T cells, within the affected region. The population of CD4 + CD11b + T cells increased in ligated CLNs, accompanied by a decrease in the average fluorescence intensity of sphingosine-1-phosphate receptor-1 (S1PR1) on these cells. Administration of CD4 + CD11b + T cells sorted from CLNs into the lateral ventricle reversed the attenuated neurologic deficits, brain edema, and lesion volume following cervical lymphadenectomy., Conclusion: The infiltration of CD4 + CD11b + T cells exacerbates secondary brain damage in TBI, and this process is modulated by brain-to-CLN signaling., (© 2024 The Authors. CNS Neuroscience & Therapeutics published by John Wiley & Sons Ltd.)

The rediscovery of meningeal lymphatic vessels (MLVs) has sparked research interest in their function in numerous neurological pathologies. Craniosynostosis (CS) is caused by a premature fusion of cranial sutures during development. In this issue of the JCI, Matrongolo and colleagues show that Twist1-haploinsufficient mice that develop CS exhibit raised intracranial pressure, diminished cerebrospinal fluid (CSF) outflow, and impaired paravascular CSF-brain flow; all features that were associated with MLV defects and exacerbated pathology in mouse models of Alzheimer's disease. Activation of the mechanosensor Piezo1 with Yoda1 restored MLV function and CSF perfusion in CS models and in aged mice, opening an avenue for further development of therapeutics.

The lymphatic system, crucial for tissue fluid balance and immune surveillance, can be severely impacted by disorders that hinder its activities. Lymphatic malformations (LMs) are caused by fluid accumulation in tissues owing to defects in lymphatic channel formation, the obstruction of lymphatic vessels or injury to lymphatic tissues. Somatic mutations, varying in symptoms based on lesions' location and size, provide insights into their molecular pathogenesis by identifying LMs' genetic causes. In this review, we collected the most recent findings about the role of genetic and inflammatory biomarkers in LMs that control the formation of these malformations. A thorough evaluation of the literature from 2000 to the present was conducted using the PubMed and Google Scholar databases. Although it is obvious that the vascular endothelial growth factor receptor 3 mutation accounts for a significant proportion of LM patients, several mutations in other genes thought to be linked to LM have also been discovered. Also, inflammatory mediators like interleukin-6, interleukin-8, tumor necrosis factor-alpha and mammalian target of rapamycin are the most commonly associated biomarkers with LM. Understanding the mutations and genes expression responsible for the abnormalities in lymphatic endothelial cells could lead to novel therapeutic strategies based on molecular pathways., (© 2024 John Wiley & Sons Ltd.)

The knowledge of the blood microvasculature and its functional role in health and disease has grown significantly attributable to decades of research and numerous advances in cell biology and tissue engineering; however, the lymphatics (the secondary vascular system) has not garnered similar attention, in part due to a lack of relevant in vitro models that mimic its pathophysiological functions. Here, a microfluidic-based approach is adopted to achieve precise control over the biological transport of growth factors and interstitial flow that drive the in vivo growth of lymphatic capillaries (lymphangiogenesis). The engineered on-chip lymphatics with in vivo-like morphology exhibit tissue-scale functionality with drainage rates of interstitial proteins and molecules comparable to in vivo standards. Computational and scaling analyses of the underlying transport phenomena elucidate the critical role of the three-dimensional geometry and lymphatic endothelium in recapitulating physiological drainage. Finally, the engineered on-chip lymphatics enabled studies of lymphatic-immune interactions that revealed inflammation-driven responses by the lymphatics to recruit immune cells via chemotactic signals similar to in vivo, pathological events. This on-chip lymphatics platform permits the interrogation of various lymphatic biological functions, as well as screening of lymphatic-based therapies such as interstitial absorption of protein therapeutics and lymphatic immunomodulation for cancer therapy., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Introduction: Quantitative, multiplexed imaging is revealing complex spatial relationships between phenotypically diverse tumor infiltrating leukocyte populations and their prognostic implications. The underlying mechanisms and tissue structures that determine leukocyte distribution within and around tumor nests, however, remain poorly understood. While presumed players in metastatic dissemination, new preclinical data demonstrates that blood and lymphatic vessels (lymphovasculature) also dictate leukocyte trafficking within tumor microenvironments and thereby impact anti-tumor immunity. Here we interrogate these relationships in primary human cutaneous melanoma., Methods: We established a quantitative, multiplexed imaging platform to simultaneously detect immune infiltrates and tumor-associated vessels in formalin-fixed paraffin embedded patient samples. We performed a discovery, retrospective analysis of 28 treatment-naïve, primary cutaneous melanomas., Results: Here we find that the lymphvasculature and immune infiltrate is heterogenous across patients in treatment naïve, primary melanoma. We categorized five lymphovascular subtypes that differ by functionality and morphology and mapped their localization in and around primary tumors. Interestingly, the localization of specific vessel subtypes, but not overall vessel density, significantly associated with the presence of lymphoid aggregates, regional progression, and intratumoral T cell infiltrates., Discussion: We describe a quantitative platform to enable simultaneous lymphovascular and immune infiltrate analysis and map their spatial relationships in primary melanoma. Our data indicate that tumor-associated vessels exist in different states and that their localization may determine potential for metastasis or immune infiltration. This platform will support future efforts to map tumor-associated lymphovascular evolution across stage, assess its prognostic value, and stratify patients for adjuvant therapy., Competing Interests: AL reports consulting services for AGS Therapeutics. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Femel, Hill, Illa Bochaca, Booth, Asnaashari, Steele, Moshiri, Do, Zhong, Osman, Leachman, Tsujikawa, White, Chang and Lund.)

Lymphatic vasculature has been shown to promote metastatic spread of breast cancer. Lymphatic vasculature, which is made up of larger collecting vessels and smaller capillaries, has specialized cell junctions that facilitate cell intravasation. Normally, these junctions are designed to collect immune cells and other cellular components for immune surveillance by lymph nodes, but they are also utilized by cancer cells to facilitate metastasis. Although lymphatic development overall in the body has been well-characterized, there has been little focus on how the lymphatic network changes in the mammary gland during stages of remodeling such as pregnancy, lactation, and postpartum involution. In this review, we aim to define the currently known lymphangiogenic factors and lymphatic remodeling events during mammary gland morphogenesis. Furthermore, we juxtapose mammary gland pubertal development and postpartum involution to show similarities of pro-lymphangiogenic signaling as well as other molecular signals for epithelial cell survival that are critical in these morphogenic stages. The similar mechanisms include involvement of M2-polarized macrophages that contribute to matrix remodeling and vasculogenesis; signal transducer and activator of transcription (STAT) survival and proliferation signaling; and cyclooxygenase 2 (COX2)/Prostaglandin E2 (PGE2) signaling to promote ductal and lymphatic expansion. Investigation and characterization of lymphangiogenesis in the normal mammary gland can provide insight to targetable mechanisms for lymphangiogenesis and lymphatic spread of tumor cells in breast cancer., (© 2024. The Author(s).)

The lymphatic vasculature is the natural pathway for the resolution of inflammation, yet the role of pulmonary lymphatic drainage function in sepsis-induced acute respiratory distress syndrome (ARDS) remains poorly characterized. In this study, indocyanine green-near infrared lymphatic living imaging was performed to examine pulmonary lymphatic drainage function in septic mouse models. We found that the pulmonary lymphatic drainage was impaired owing to the damaged lymphatic structure in sepsis-induced ARDS. Moreover, prior lymphatic defects by blocking vascular endothelial growth factor receptor-3 (VEGFR-3) worsened sepsis-induced lymphatic dysfunction and inflammation. Posttreatment with vascular endothelial growth factor-C (Cys156Ser) (VEGF-C156S), a ligand of VEGFR-3, ameliorated lymphatic drainage by rejuvenating lymphatics to reduce the pulmonary edema and promote draining of pulmonary macrophages and neutrophils to pretracheal lymph nodes. Meanwhile, VEGF-C156S posttreatment reversed sepsis-inhibited CC chemokine ligand 21 (CCL21), which colocalizes with pulmonary lymphatic vessels. Furthermore, the advantages of VEGF-C156S on the drainage of inflammatory cells and edema fluid were abolished by blocking VEGFR-3 or CCL21. These results suggest that efficient pulmonary lymphatic drainage is necessary for inflammation resolution in ARDS. Our findings offer a therapeutic approach to sepsis-induced ARDS by promoting lymphatic drainage function.

Despite strong indications that interactions between melanoma and lymphatic vessels actively promote melanoma progression, the molecular mechanisms are not yet completely understood. To characterize molecular factors of this crosstalk, we established human primary lymphatic endothelial cell (LEC) cocultures with human melanoma cell lines. Here, we show that coculture with melanoma cells induced transcriptomic changes in LECs and led to multiple changes in their function. WNT5B, a paracrine signaling molecule upregulated in melanoma cells upon LEC interaction, was found to contribute to the functional changes in LECs. Moreover, WNT5B transcription was regulated by Notch3 in melanoma cells following the coculture with LECs, and Notch3 and WNT5B were coexpressed in melanoma patient primary tumor and metastasis samples. Moreover, melanoma cells derived from LEC coculture escaped efficiently from the primary site to the proximal tumor-draining lymph nodes, which was impaired upon WNT5B depletion. This supported the role of WNT5B in promoting the metastatic potential of melanoma cells through its effects on LECs. Finally, DLL4, a Notch ligand expressed in LECs, was identified as an upstream inducer of the Notch3/WNT5B axis in melanoma. This study elucidated WNT5B as a key molecular factor mediating bidirectional crosstalk between melanoma cells and lymphatic endothelium and promoting melanoma metastasis.

Lymphatic vessels, comprising the secondary circulatory system in human body, play a multifaceted role in maintaining homeostasis among various tissues and organs. They are tasked with a serious of responsibilities, including the regulation of lymph absorption and transport, the orchestration of immune surveillance and responses. Lymphatic vessel development undergoes a series of sophisticated regulatory signaling pathways governing heterogeneous-origin cell populations stepwise to assemble into the highly specialized lymphatic vessel networks. Lymphangiogenesis, as defined by new lymphatic vessels sprouting from preexisting lymphatic vessels/embryonic veins, is the main developmental mechanism underlying the formation and expansion of lymphatic vessel networks in an embryo. However, abnormal lymphangiogenesis could be observed in many pathological conditions and has a close relationship with the development and progression of various diseases. Mechanistic studies have revealed a set of lymphangiogenic factors and cascades that may serve as the potential targets for regulating abnormal lymphangiogenesis, to further modulate the progression of diseases. Actually, an increasing number of clinical trials have demonstrated the promising interventions and showed the feasibility of currently available treatments for future clinical translation. Targeting lymphangiogenic promoters or inhibitors not only directly regulates abnormal lymphangiogenesis, but improves the efficacy of diverse treatments. In conclusion, we present a comprehensive overview of lymphatic vessel development and physiological functions, and describe the critical involvement of abnormal lymphangiogenesis in multiple diseases. Moreover, we summarize the targeting therapeutic values of abnormal lymphangiogenesis, providing novel perspectives for treatment strategy of multiple human diseases., (© 2023. The Author(s).)