Search

Meningeal lymphatics are conduits for cerebrospinal fluid drainage to lymphatics and lymph nodes in the neck. In this issue of JEM, Boisserand et al. (https://doi.org/10.1084/jem.20221983) provide evidence that expansion of meningeal lymphatics protects against ischemic stroke.

Cerebrospinal fluid (CSF) in the subarachnoid space around the brain has long been known to drain through the lymphatics to cervical lymph nodes1-17, but the connections and regulation have been challenging to identify. Here, using fluorescent CSF tracers in Prox1-GFP lymphatic reporter mice18, we found that the nasopharyngeal lymphatic plexus is a major hub for CSF outflow to deep cervical lymph nodes. This plexus had unusual valves and short lymphangions but no smooth-muscle coverage, whereas downstream deep cervical lymphatics had typical semilunar valves, long lymphangions and smooth muscle coverage that transported CSF to the deep cervical lymph nodes. α-Adrenergic and nitric oxide signalling in the smooth muscle cells regulated CSF drainage through the transport properties of deep cervical lymphatics. During ageing, the nasopharyngeal lymphatic plexus atrophied, but deep cervical lymphatics were not similarly altered, and CSF outflow could still be increased by adrenergic or nitric oxide signalling. Single-cell analysis of gene expression in lymphatic endothelial cells of the nasopharyngeal plexus of aged mice revealed increased type I interferon signalling and other inflammatory cytokines. The importance of evidence for the nasopharyngeal lymphatic plexus functioning as a CSF outflow hub is highlighted by its regression during ageing. Yet, the ageing-resistant pharmacological activation of deep cervical lymphatic transport towards lymph nodes can still increase CSF outflow, offering an approach for augmenting CSF clearance in age-related neurological conditions in which greater efflux would be beneficial.

Background Persistent macrophage infiltration may lead to adverse consequences, such as calcifications and nodules in fat grafts. Lymphatic vessels, which transport inflammatory cells, are involved in regulating inflammatory responses. Less is known, however, about lymphatic vessels after fat grafting. Objectives The aim of this study was to explore the regulation of fat graft survival by lymphatic vessels. Methods A common adipose graft model was constructed to assess the processes responsible for changes in the number of lymphatic vessels in grafts. Adipose tissue samples from C57/BL6 mice and green fluorescent protein–expressing mice were cross-grafted to determine the source of lymphatic vessels. The number of lymphatic vessels in the grafts was increased by treatment with vascular endothelial growth factor C, and the effects of this increase on fat grafting were evaluated. Results The number of lymphatic vessels was greater in postgrafted fat than in inguinal fat before transplantation, with lymphatic vessels in these grafts gradually transitioning from donor to recipient sources. Lymphatic vessels grew more slowly than blood vessels during early stages of grafting; during later stages, however, the number of blood vessels declined markedly, with more lymphatic vessels than blood vessels being observed 60 days after grafting. Vascular endothelial growth factor C treatment increased graft lymphatics and distant volume retention, while reducing fibrosis and oil sacs. Lymphatic vessels acted as drainage channels for macrophages, with the degree of sustained macrophage infiltration decreasing with increases in the number of lymphatic vessels. Conclusions Increasing the number of lymphatic vessels is beneficial for fat graft survival, which may be related to a reduction in prolonged macrophage infiltration. Level of Evidence: 4 [ABSTRACT FROM AUTHOR]

Background: The contribution of the tumor microenvironment and extracellular matrix to the aggressive biology of Gastric Cancer (GC) has been recently characterized; however, the role of EMILIN-1 in this context is unknown. EMILIN-1 is an essential structural element for the maintenance of lymphatic vessel (LV) integrity and displays anti-proliferative properties as demonstrated in skin and colon cancer. Given the key role of LVs in GC progression, the aim of this study was to investigate the role of EMILIN-1 in GC mouse models. Methods: We used the syngeneic YTN16 cells which were injected subcutaneously and intraperitoneally in genetically modified EMILIN-1 mice. In alternative, carcinogenesis was induced using N-Methyl-N-nitrosourea (MNU). Mouse-derived samples and human biopsies were analyzed by IHC and IF to the possible correlation between EMILIN-1 expression and LV pattern. Results: Transgenic mice developed tumors earlier compared to WT animals. 20 days post-injection tumors developed in EMILIN-1 mutant mice were larger and displayed a significant increase of lymphangiogenesis. Treatment of transgenic mice with MNU associated with an increased number of tumors, exacerbated aggressive lesions and higher levels of LV abnormalities. A significant correlation between the levels of EMILIN-1 and podoplanin was detected also in human samples, confirming the results obtained with the pre-clinical models. Conclusions: This study demonstrates for the first time that loss of EMILIN-1 in GC leads to lymphatic dysfunction and proliferative advantages that sustain tumorigenesis, and assess the use of our animal model as a valuable tool to verify the fate of GC upon loss of EMILIN-1. [ABSTRACT FROM AUTHOR]

Ovarian lymphangiomas are rare benign neoplasms characterized by the proliferation of lymphatic vessels within the ovarian tissue. While lymphangiomas can manifest in various anatomical locations, their occurrence within the ovaries is exceptionally uncommon, posing diagnostic and therapeutic challenges for clinicians. The aetiology of ovarian lymphangiomas remains elusive, with theories suggesting congenital malformations, lymphatic obstruction, or acquired lymphatic proliferation as potential contributing factors. The clinical presentation of ovarian lymphangiomas often includes nonspecific symptoms such as abdominal pain, swelling, or discomfort, leading to difficulties in early detection and diagnosis. Radiological imaging, particularly Ultrasound, CT (computed tomography) and MRI (magnetic resonance imaging), plays a crucial role in identifying these lesions and guiding subsequent management strategies. Despite their generally benign nature, ovarian lymphangiomas can attain significant sizes, causing complications such as torsion, rupture, or compression of adjacent structures. Surgical intervention, typically in cystectomy or oophorectomy, is frequently pursued to alleviate symptoms and prevent potential complications. This paper aims to comprehensively review the existing literature on ovarian lymphangiomas, addressing their clinical presentation, diagnostic challenges, and management strategies. By synthesizing available data, we seek to enhance our understanding of this rare entity, providing valuable insights for clinicians encountering similar cases. Improved awareness and knowledge of ovarian lymphangiomas are essential for timely diagnosis and optimal patient outcomes.

Abstract 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.

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. [ABSTRACT FROM AUTHOR]

Cancer dissemination to lymph nodes (LN) is associated with a worse prognosis, increased incidence of distant metastases and reduced response to therapy. The LN microenvironment puts selective pressure on cancer cells, creating cells that can survive in LN as well as providing survival advantages for distant metastatic spread. Additionally, the presence of cancer cells leads to an immunosuppressive LN microenvironment, favoring the evasion of anti-cancer immune surveillance. However, recent studies have also characterized previously unrecognized roles for tumor-draining lymph nodes (TDLNs) in cancer immunotherapy response, including acting as a reservoir for pre-exhausted CD8+ T cells and stem-like CD8+ T cells. In this review, we will discuss the spread of cancer cells through the lymphatic system, the roles of TDLNs in metastasis and anti-cancer immune responses, and the therapeutic opportunities and challenges in targeting LN metastasis. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Since its recent discovery, the meningeal lymphatic system has reshaped our understanding of central nervous system (CNS) fluid exchange, waste clearance, immune cell trafficking, and immune privilege. Meningeal lymphatics have also been demonstrated to functionally modify the outcome of neurological disorders and their responses to treatment, including brain tumors, inflammatory diseases such as multiple sclerosis, CNS injuries, and neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. In this review, we discuss recent evidence of the contribution of meningeal lymphatics to neurological diseases, as well as the available experimental methods for manipulating meningeal lymphatics in these conditions. Finally, we also provide a discussion of the pressing questions and challenges in utilizing meningeal lymphatics as a prime target for CNS therapeutic intervention and possibly drug delivery for brain disorders. [ABSTRACT FROM AUTHOR]

Objective. To find out whether the use of indocyanine green for lymphatic sparing in the laparoscopic Palomo technique reduces the incidence of postoperative hydrocele. Materials and methods. A comparative cohort study of varicocele patients treated with the laparoscopic Palomo technique from 2008 to 2023 was carried out. Patients were divided into two groups according to whether fluorescence lymphography (intratesticular indocyanine green) had been performed or not. Epidemiological, surgical, and clinical data, as well as complications, were recorded. A hypothesis test was conducted using the SPSS software. Results. 30 patients undergoing varicocele surgery through the laparoscopic Palomo technique were included. They were divided into two groups –lymphatic sparing (n= 13) vs. spermatic vessel ligation without sparing (n= 17). Mean age at surgery was 14 years. 5 cases of postoperative hydrocele were identified in the no lymphatic sparing group. 1 of them required surgery for hydrocele treatment. No hydrocele cases were noted in the lymphography group. The difference was statistically significant (p= 0.032). There were no statistically significant differences in terms of operating times or mean hospital stay. No recurrences, postoperative testicular atrophies, or indocyanine-green-related complications were recorded. Mean follow-up was 11.4 months. Conclusions. The use of indocyanine green for lymphatic sparing in the treatment of varicocele through the laparoscopic Palomo technique significantly reduces the incidence of postoperative hydrocele. [ABSTRACT FROM AUTHOR]

[Display omitted] • Macromolecular substances in the spinal canal can enter the thoracic duct. • Changes of lymphatic drainage velocity after spinal cord injury. • Reducing the outflow of spinal lymphatic vessels aggravates the pathological process after spinal cord injury. We aimed to evaluate the role of the spinal lymphatic system in spinal cord injury and whether it has an impact on recovery after spinal cord injury. Flow cytometry was used to evaluate the changes in the number of microvesicles after spinal cord injury. Evans blue extravasation was used to evaluate the function of the lymphatic system. Evans blue extravasation and immunofluorescence were used to evaluate the permeability of blood spinal cord barrier. The spinal cord edema was evaluated by dry and wet weight. Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay was used to evaluate apoptosis after spinal cord injury. Nuclear factor-kappa B pathway was detected by Western blot. Behavioral tests were used to evaluate limb function. Microvesicles released after spinal cord injury can enter the thoracic duct and then enter the blood through the lymph around the spine. After ligation of the thoracic duct, it can aggravate the neuropathological manifestations and limb function after spinal cord injury. The potential mechanism may involve nuclear factor-kappa B pathway. [ABSTRACT FROM AUTHOR]

Cystic Hygroma (CH) also referred to as lymphangioma, is a cystic malformation of the lymphatic vessels that can occur anywhere in the body. Its incidence in adulthood is considered rare and its occurrence in the neck is even rarer and only a few case reports are available till date. We present a case of adult CH of the neck and the literature review of the same. A 30-year-old male presented with painless swelling in the left side of the neck of 2 years duration. Investigations showed a cystic mass on the left lower anterior part of the neck which was surgically removed in-toto with the intact capsule. The biopsy report confirmed the diagnosis. A differential diagnosis of CH should be considered when a cystic lesion is encountered in the neck of an adult, cytological and radiological evaluation is necessary for defining its location and diagnosis. Although various conservative modalities of management are available, they are employed only in certain situations, and surgical excision of CH is considered the gold standard. The chances of recurrence range from 15 to 20%. [ABSTRACT FROM AUTHOR]

Summary: Background: Atraumatic subarachnoid haemorrhage (SAH) is associated with high morbidity and mortality. Proposed mechanisms for red blood cell (RBC) clearance from the subarachnoid space (SAS) are erythrolysis, erythrophagocytosis or through efflux along cerebrospinal fluid (CSF) drainage routes. We aimed to elucidate the mechanisms of RBC clearance from the SAS to identify targetable efflux pathways. Methods: Autologous fluorescently-labelled RBCs along with PEGylated 40 kDa near-infrared tracer (P40D800) were infused via the cisterna magna (i.c.m.) in female reporter mice for lymphatics or for resident phagocytes. Drainage pathways for RBCs to extracranial lymphatics were evaluated by in vivo and in situ near-infrared imaging and by immunofluorescent staining on decalcified cranial tissue or dural whole-mounts. Findings: RBCs drained to the deep cervical lymph nodes 15 min post i.c.m. infusion, showing similar dynamics as P40D800 tracer. Postmortem in situ imaging and histology showed perineural accumulations of RBCs around the optic and olfactory nerves. Numerous RBCs cleared through the lymphatics of the cribriform plate, whilst histology showed no relevant fast RBC clearance through dorsal dural lymphatics or by tissue-resident macrophage-mediated phagocytosis. Interpretation: This study provides evidence for rapid RBC drainage through the cribriform plate lymphatic vessels, whilst neither fast RBC clearance through dorsal dural lymphatics nor through spinal CSF efflux or phagocytosis was observed. Similar dynamics of P40D800 and RBCs imply open pathways for clearance that do not impose a barrier for RBCs. This finding suggests further evaluation of the cribriform plate lymphatic function and potential pharmacological targeting in models of SAH. Funding: Swiss National Science Foundation (310030_189226), SwissHeart (FF191155).

Diffuse pulmonary lymphangiomatosis (DLP) is an extremely rare silent disease, characterized by proliferation and thickening of abnormal pulmonary, pleural, and mediastinal soft tissue lymphatic channels. Its clinical presentation is nonspecific symptoms such as cough, dyspnea, and hemoptysis. Tomographic findings for DLP include thickening of the interlobular septa and peribronchovascular interstitium and ground glass opacities. Nevertheless, the anterior mediastinal mass, associated with thickening of interlobular septa and peribronchovascular interstitial, ground glass opacities, pleural effusion, diffuse infiltration of the mediastinum and pleural thickening in a patient with lymphangiomas, DLP should be suspected as a differential diagnosis. [ABSTRACT FROM AUTHOR]

Despite the large arsenal of diagnostic methods for studying the lymphatic system, there are isolated works on its morpho-functional state in chronic venous insufluciency. The purpose of the study was to study the anatomical and physiological state of the surface lymphatic system of the lower extremities in persons with different clinical classes of chronic vein diseases using fluorescence lifography. The study was conducted in 105 patients divided into six groups according to the clinical class of chronic diseases of the veins of the lower extremities according to the CEAP classiffication. We used fluorescent lymphography using sodium fluorescein to study the anatomical and functional capabilities of the lymphotone. The study revealed that morphofunctional changes in superficial lymphatic vessels in chronic lower extremity vein diseases depend on venous system decompensation. With an increase in the clinical class of chronic diseases of the veins of the lower extremities, the rate of lymph flow through the superficial lymphatic vessels is statistically significantly reduced. At the same time, the antegrade lymph cell is completely absent in С5-С6, with the appearance of retrograde outflow and discharge of the lymph into the deep lymph vessels. Thus, the progression of chronic venous insufficiency leads to proportional progression of morphofunctional changes in the superficial lymphatic system, which leads to the formation of lymphovenous insufficiency.

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Purpose: Caries or iatrogenic thermal trauma of the teeth have a significant impact on the dental pulp structure connected with stimulation of angiogenesis and lymphangiogenesis. Therefore, the aim of the study was to identify the difference in the rate of heat dissipation by vessels present in the dental pulp. Methods: Freshly extracted healthy (n = 10) and carious (n = 14) molars and premolars were cut on a diamond saw and subjected to active thermographic examination and then subjected to lymphoscintigraphy and X-ray examination. The tooth samples were heated uniformly to 40 ± 0.5 °C. A thermal imaging camera with a resolution of 640 × 320 pixels was used to record the sequence of thermograms during free cooling. Due to the different volume of teeth and different surface conditions of the examined teeth (color, roughness) and the related different radiation emissivity, the changes in the temperature (ΔT) of the tooth cross-section surface were analyzed using the subtractive method within 120 seconds from the switching off of the thermal impulse (heating). Results: Thermographic examination of healthy and cariously changed teeth revealed areas of increased tissue fluid flow combined with heat release, which may indirectly indicate the existence of vessels in these areas. On a thermal imaging camera, variations in the rate of heating or cooling across several cross-sectional sections of the same tooth indicate changes in the dental structure's density. Conclusions: In caries-affected teeth, intracanalicular fluid flows are different than those of healthy teeth. Therefore, it can be concluded that the pulp vessels enabling circulation of body fluids - blood and lymphatic - increases with the intensity of inflammation. Maintaining the homeostasis of the dental pulp depends heavily on the circulation of bodily fluids within the dental organ. [ABSTRACT FROM AUTHOR]

Background: Contraction-type lymphatic vessels (LV) are considered suboptimal for lymphaticovenous anastomosis (LVA). However, despite these pathological changes, their functionality and link to outcomes have not been fully elucidated. The aim of this study was to determine the impact on outcomes when contraction-type LVs were used for LVA compared to the noncontractiontype (normal + ectatic) counterpart for treating lower limb lymphedema. Study design: Eighty-three patients with gynecologic cancer-related unilateral lower-limb lymphedema who underwent LVA as their primary treatment were enrolled in this study. The study group included 20 patients who used only contraction-type LVs. An additional 63 patients (control group) received noncontraction-type LVs only. Patients with a history of LVA, liposuction, or excisional therapy were excluded. Patient characteristics, intraoperative findings, functional parameters, and pre-LVA and post-LVA volume changes were recorded and matched using propensity scores. The primary endpoint was the volume change at 6/12 months after LVA. Results: After matching, 20 patients were included in each group. All parameters were matched, except that the study group still had a significantly inferior indocyanine green (ICG)-positive ratio, lymph flow-positive ratio, and washout-positive ratios (P< 0.001, P =0.003, and P<0.001, respectively) when compared to the control group after matching. However, at 1-year follow-up, the postoperative percentage volume reduction was comparable between the groups (P =0.619). Conclusion: The use of contraction-type LVs for LVA is encouraged when no other LVs are available. [ABSTRACT FROM AUTHOR]

Immunohistochemical detection of the LYVE-1 marker in healthy human full-thickness skin (the epidermis and the dermis) was carried out. LYVE-1 expression was found in the endothelium of lymphatic capillaries located in the papillary dermis, in the endothelium of larger lymphatic vessels of the reticular dermis, and in fibroblasts, which indicates their joint participation in hyaluronan metabolism. LYVE-1+ staining detected for the first time in cells of the stratum basale, the stratum spinosum, and the stratum granulosum of healthy human epidermis indicates their participation in hyaluronan metabolism and allows us to consider the spaces between epidermis cells as prelimphatics. [ABSTRACT FROM AUTHOR]

Parathyroid tumors exhibit distinct histopathological features that differentiate benign from malignant lesions. This study aimed to study characteristic distribution of lymphatic and blood vessels in normal parathyroid gland and parathyroid tumors to distinguish cancer from benign tumors. Immunohistochemical staining for lymphatic and blood vessels and parathyroid hormone was performed with parathyroid proliferating lesions including adenoma, multiglandular multiple adenomas, atypical tumor, and carcinoma. Lymphatic vessels were immunostained with lymphatic vessel endothelial receptor 1 (LYVE-1) and blood vessels were immunostained with von Willebrand factor (vWf). Normal parathyroid gland contained several round blood vessels with less linear lymphatic vessels. The less parathormone-immunostained adenomas weighing less than 2 g revealed larger blood vessels with perivascular small linear lymphatic vessels, and the larger adenomas contained proportionally larger blood vessels. Smaller multiglandular multiple adenomas were like smaller adenomas with less parathormone staining and contained larger, round blood vessels with perivascular small linear lymphatic vessels. Larger multiglandular multiple adenomas weighing more than 4 g and one atypical tumor contained nodular pattern consisted of alternating strongly parathormone-positive lobes and negative lobes with numerous, dilated blood vessels and perivascular linear lymphatic vessels. Both primary and metastatic carcinomas were strongly and diffusely positive for parathyroid hormone with numerous lymphatic and blood vessels at the invading margin. Thus, normal parathyroid has rich blood vessels which provide accessibility of minced tissues seeding for auto-transplantation. Immunostaining patterns of parathyroid hormone, lymphatic and blood vessels help to distinguish carcinoma from benign parathyroid proliferating lesions. The negative immunohistochemical staining for parafibromin will detect carriers of hyperparathyroidism-jaw tumor (HPT-JT) syndrome and would help in diagnosing parathyroid cancer in both HPT-JT carriers and sporadic patients.

Abstract Lymphatic system distributes in almost all vertebrate tissues and organs, and plays important roles in the regulation of body fluid balance, lipid absorption and immune monitoring. Although CuNPs or AgNPs accumulation has been reported to be closely associated with delayed hatching and motor dysfunction in zebrafish embryos, their biological effects on lymphangiogenesis remain unknown. In this study, thoracic duct was observed to be partially absent in both CuNPs and AgNPs stressed zebrafish larvae. Specifically, CuNPs stress induced hypermethylation of E2F7/8 binding sites on CCBE1 promoters via their producing ROS, thereby leading to the reduction of binding enrichment of E2F7/8 on CCBE1 promoter and its subsequently reduced expression, then resulting in defective lymphatic vessel formation. Differently, AgNPs stress induced down-regulated CCBE1 expression via down-regulating mRNA and protein levels of E2F7/8 transcription factors, thereby resulting in defective lymphatic vessel formation. This study may be the first to demonstrate that CuNPs and AgNPs damaged lymphangiogenesis during zebrafish embryogenesis, mechanistically, CuNPs epigenetically regulated the expression of lymphangiogenesis regulator CCBE1 via hypermethylating its promoter binding sites of E2F7/8, while AgNPs via regulating E2F7/8 expression. Meanwhile, overexpression of ccbe1 mRNA effectively rescued the lymphangiogenesis defects in both AgNPs and CuNPs stressed larvae, while overexpression of e2f7/8 mRNA effectively rescued the lymphangiogenesis defects in AgNPs rather than CuNPs stressed larvae. The results in this study will shed some light on the safety assessment of nanomaterials applied in medicine and on the ecological security assessments of nanomaterials. Video Abstract

BackgroundMutations in PIEZO1 (Piezo type mechanosensitive ion channel component 1) cause human lymphatic malformations. We have previously uncovered an ORAI1 (ORAI calcium release-activated calcium modulator 1)-mediated mechanotransduction pathway that triggers lymphatic sprouting through Notch downregulation in response to fluid flow. However, the identity of its upstream mechanosensor remains unknown. This study aimed to identify and characterize the molecular sensor that translates the flow-mediated external signal to the Orai1-regulated lymphatic expansion.MethodsVarious mutant mouse models, cellular, biochemical, and molecular biology tools, and a mouse tail lymphedema model were employed to elucidate the role of Piezo1 in flow-induced lymphatic growth and regeneration.ResultsPiezo1 was found to be abundantly expressed in lymphatic endothelial cells. Piezo1 knockdown in cultured lymphatic endothelial cells inhibited the laminar flow-induced calcium influx and abrogated the flow-mediated regulation of the Orai1 downstream genes, such as KLF2 (Krüppel-like factor 2), DTX1 (Deltex E3 ubiquitin ligase 1), DTX3L (Deltex E3 ubiquitin ligase 3L,) and NOTCH1 (Notch receptor 1), which are involved in lymphatic sprouting. Conversely, stimulation of Piezo1 activated the Orai1-regulated mechanotransduction in the absence of fluid flow. Piezo1-mediated mechanotransduction was significantly blocked by Orai1 inhibition, establishing the epistatic relationship between Piezo1 and Orai1. Lymphatic-specific conditional Piezo1 knockout largely phenocopied sprouting defects shown in Orai1- or Klf2- knockout lymphatics during embryo development. Postnatal deletion of Piezo1 induced lymphatic regression in adults. Ectopic Dtx3L expression rescued the lymphatic defects caused by Piezo1 knockout, affirming that the Piezo1 promotes lymphatic sprouting through Notch downregulation. Consistently, transgenic Piezo1 expression or pharmacological Piezo1 activation enhanced lymphatic sprouting. Finally, we assessed a potential therapeutic value of Piezo1 activation in lymphatic regeneration and found that a Piezo1 agonist, Yoda1, effectively suppressed postsurgical lymphedema development.ConclusionsPiezo1 is an upstream mechanosensor for the lymphatic mechanotransduction pathway and regulates lymphatic growth in response to external physical stimuli. Piezo1 activation presents a novel therapeutic opportunity for preventing postsurgical lymphedema. The Piezo1-regulated lymphangiogenesis mechanism offers a molecular basis for Piezo1-associated lymphatic malformation in humans.

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. [ABSTRACT FROM AUTHOR]

Lymphatic vessels are actively involved in the recovery process of inflamed tissues. However, the changes in intramuscular lymphatic vessels during inflammation caused by skeletal muscle injury remain unclear. Therefore, the purpose of this study was to clarify the changes in lymphatic vessels after skeletal muscle injury. The left tibialis anterior muscles of male mice were subjected to lengthening contractions (LC) for inducing skeletal muscle injury, and samples were collected on Days 2, 4, and 7 for examining changes in both the skeletal muscles and intramuscular lymphatic vessels. With hematoxylin–eosin staining, the inflammatory response was observed in myofibers on Days 2 and 4 after LC, whereas regeneration of myofibers was found on Day 7 after LC. The number and area of intramuscular lymphatic vessels analyzed by immunohistochemical staining with an antibody against lymphatic vessel endothelial hyaluronan receptor 1 were significantly increased only on Day 4 after LC. Based on the abovementioned results, intramuscular lymphatic vessels undergo morphological changes such as increase under the state of muscle inflammation. This study demonstrated that the morphology of intramuscular lymphatic vessels undergoes significant changes during the initial recovery phase following skeletal muscle injury. [ABSTRACT FROM AUTHOR]

Historically, research into the lymphatic system has been overlooked due to both a lack of knowledge and limited recognition of its importance. In the last decade however, lymphatic research has gained substantial momentum and has included the development of a variety of computational models to aid understanding of this complex system. This article reviews existing computational fluid dynamic models of the lymphatics covering each structural component including the initial lymphatics, pre-collecting and collecting vessels, and lymph nodes. This is followed by a summary of limitations and gaps in existing computational models and reasons that development in this field has been hindered to date. Over the next decade, efforts to further characterize lymphatic anatomy and physiology are anticipated to provide key data to further inform and validate lymphatic fluid dynamic models. Development of more comprehensive multiscale- and multi-physics computational models has the potential to significantly enhance the understanding of lymphatic function in both health and disease. [ABSTRACT FROM AUTHOR]

Lymphatic system distributes in almost all vertebrate tissues and organs, and plays important roles in the regulation of body fluid balance, lipid absorption and immune monitoring. Although CuNPs or AgNPs accumulation has been reported to be closely associated with delayed hatching and motor dysfunction in zebrafish embryos, their biological effects on lymphangiogenesis remain unknown. In this study, thoracic duct was observed to be partially absent in both CuNPs and AgNPs stressed zebrafish larvae. Specifically, CuNPs stress induced hypermethylation of E2F7/8 binding sites on CCBE1 promoters via their producing ROS, thereby leading to the reduction of binding enrichment of E2F7/8 on CCBE1 promoter and its subsequently reduced expression, then resulting in defective lymphatic vessel formation. Differently, AgNPs stress induced down-regulated CCBE1 expression via down-regulating mRNA and protein levels of E2F7/8 transcription factors, thereby resulting in defective lymphatic vessel formation. This study may be the first to demonstrate that CuNPs and AgNPs damaged lymphangiogenesis during zebrafish embryogenesis, mechanistically, CuNPs epigenetically regulated the expression of lymphangiogenesis regulator CCBE1 via hypermethylating its promoter binding sites of E2F7/8, while AgNPs via regulating E2F7/8 expression. Meanwhile, overexpression of ccbe1 mRNA effectively rescued the lymphangiogenesis defects in both AgNPs and CuNPs stressed larvae, while overexpression of e2f7/8 mRNA effectively rescued the lymphangiogenesis defects in AgNPs rather than CuNPs stressed larvae. The results in this study will shed some light on the safety assessment of nanomaterials applied in medicine and on the ecological security assessments of nanomaterials. -5JubNCLudCTXxnkfqD8au Video Abstract [ABSTRACT FROM AUTHOR]

Open in new tab Download slide OBJECTIVES Chylothorax is a complex condition and many different pharmacological agents have been tried as treatment. Octreotide is used off-label to treat chylothorax, but the efficacy of octreotide remains unclear. A decrease in lymph production is suggested as the mechanism. In this cross-over study, we explore the direct effect of octreotide on human lymphatic drainage. METHODS Pre-clinical: the effect of octreotide on force generation was assessed during acute and prolonged drug incubation on human lymphatic vessels mounted in a myograph. Clinical: in a double-blinded, randomized, cross-over trial including 16 healthy adults, we administered either octreotide or saline as an intravenous infusion for 2.5 h. Near-infrared fluorescence imaging was used to examine spontaneous lymphatic contractions and lymph pressure in peripheral lymphatic vessels and plethysmography was performed to assess the capillary filtration rate, capillary filtration coefficient and isovolumetric pressures of the lower leg. RESULTS Pre-clinical: human thoracic duct (n  = 12) contraction rate was concentration-dependently stimulated by octreotide with a maximum effect at 10 and 100 nmol/l in the myograph chamber. Clinical: spontaneous lymphatic contractions and lymph pressure evaluated by near-infrared fluorescence did not differ between octreotide or placebo (P  = 0.36). Plethysmography revealed similar capillary filtration coefficients (P  = 0.057), but almost a doubling of the isovolumetric pressures (P  = 0.005) during octreotide infusion. CONCLUSIONS Octreotide stimulated lymphatic contractility in the pre-clinical setup but did not affect the spontaneous lymphatic contractions or lymph pressure in healthy individuals. Plethysmography revealed a doubling in the isovolumetric pressure. These results suggest that octreotide increases lymphatic drainage capacity in situations with high lymphatic afterload. [ABSTRACT FROM AUTHOR]

Introduction: There has been an increase in the incidence of spinal epidural abscesses in the recent years. Most published series do not distinguish abscesses secondary to spondylodiscitis from non-associated with spondylodiscitis that originate directly in the epidural space. Materials and Methods: During the period from March 2014 to March 2022, 4 patients (two females and two males) aged from 48 to 70 years with spinal epidural abscesses without presence of spondylodiscitis, were treated at our institution. The history, clinical presentation, paraclinical and imaging data, the type of treatment and outcome were analyzed. Results: All patients had vertebralgia, and in three of the cases it was accompanied by pronounced motor and sensory deficits. Abscesses were located in the cervicothoracic region in two patients, in the thoracic region in one, and in the thoracolumbar region in one, involving segments 5, 7, 4, and 11, respectively. In all patients, a posterior operative access was used -- laminectomy, through which decompression of the nerve structures and evacuation of the epidural abscess was achieved. Staphylococcus aureus was isolated from the abscess in three cases. Postoperatively, the neurologic deficits improved in all patients except for one, who developed uncontrollable sepsis and multiple organ failure and died 48 hours after surgery. The last patient was diagnosed with COVID-19 during the second week, and the patient died on day 35. Conclusion: In pure spinal epidural abscesses not associated with spondylodiscitis, there is no involvement of the vertebral bodies by the infection, which significantly reduces the risk of subsequent development of instability, and spinal fusion is required only in isolated cases. [ABSTRACT FROM AUTHOR]

Objective We aimed to explore whether Taohongyin (peach seed, safflower, Sichuan lovage rhizome, Chinese angelica root-tip, and Chinese clematis root) treats atherosclerosis by regulating macrophage-mediated lymphangiogenesis. Methods The effective components of Taohongyin were identified by UPLC-Q-TOF-MS. RAW264.7 macrophages were transfected with a lentiviral vascular endothelial growth factor C (VEGFC) overexpression construct, a VEGFC knockdown construct (OE-VEGFC), and empty vector (OE-VEHICLE). The atherosclerotic cell model was constructed on RAW264.7 macrophages (ModelRAW264) or on OE-VEGFC (ModelOE-VEGFC) by intervention with human oxidized low density lipoprotein (20 mg/L) and lipopolysaccharide (100 µg/L). The optimal concentration of Taohongyin was determined by the CCK-8 method. A Transwell co-culture model of RAW264.7 macrophages and mouse lymphatic endothelial cells (MLECs) was constructed. Wound healing was assessed by the scratch test. Migration of cells was analyzed by a Transwell assay followed by crystal violet staining. Tube formation was analyzed by the tube formation assay. The contents of VEGFC, interleukin-6 (IL-6), and inducible nitric oxide synthase (iNOS) in the supernatant were determined by ELISA. The VEGFC content was determined by immunofluorescence labeling. The mRNA levels of VEGFC, lymphatic endothelial cell surface receptor (FLT4), podoplanin (PDPN), IL-6, and iNOS were determined by real-time fluorescence quantitative PCR. The protein expression levels of VEGFC, FLT4, HIF-1a, lymphatic vessel endothelial hyaluronic receptor 1 (LYVE-1), homeobox gene transcription factor 1 (Prox-1), IL-6, and iNOS were determined by Western blotting. Results UPLC- Q-TOF-MS identified 22 main active components in Taohongyin, in which hydroxysafflor yellow A (23.3%) and D-amygdalin (23.8%) were at the highest levels. A Taohongyin concentration of 20 mg/L was selected as the optimal concentration. The transfection efficiency of OE-VEGFC and OE-VEHICLE was more than 80%, indicating that the RAW264.7 macrophage VEGFC overexpression model was successfully constructed. Compared with the normal control group, the wound healing capacity of MLECs was significantly increased, cell migration and tube formation were enhanced (all P<0. 05), VEGFC fluorescence was increased (all P < 0.05), the contents of VEGFC, IL-6, and iNOS in the supernatant were increased (all P < 0.05), the mRNA expressions of VEGFC, FLT4, PDPN, IL-6, and iNOS were increased (all P < 0.05), and the protein expressions of VEGFC, FLT4, HIF-1α, LYVE-1, Prox-1, IL-6, and iNOS were increased (all P < 0.05) in the ModelRAW264.7 group. After intervention with Taohongyin of 20 mg/L, all the indicators were decreased (all P < 0.05). Compared with the ModelRAW264.7 group, all the indicators in the ModelOE-VEGFC group were increased (all P < 0.05). Compared with the Taohongyin+ModelRAW264.7 group, all the indicators in the Taohongyin+ModelOE-VEGFC group were increased (all P<0.05). Compared with the ModelOE-VEGFC group, all the indicators in the Taohongyin + ModelOE VEGFC group were decreased (all P < 0.05). Conclusion Taohongyin may reduce macrophage-mediated lymphangiogenesis by inhibiting the VEGFC pathway. [ABSTRACT FROM AUTHOR]

We report a case of a second free jejunal transfer to treat metastasis in the mesenteric lymph node of the first jejunal flap. A 73-year-old man underwent total pharyngolaryngectomy, bilateral neck dissection, and free jejunal transfer for recurrent hypopharyngeal cancer [left pyriform sinus, pT2N0, moderately differentiated squamous cell carcinoma (SCC)] after radiotherapy. Seven years post-surgery, he underwent transoral videolaryngoscopic surgery for oropharyngeal cancer (soft palate, pT1N0, well-differentiated SCC). Ten years after the first jejunal transfer, metastasis was found in the mesenteric lymph node surrounding the jejunal flap's vascular pedicle. Under general anesthesia, resection of the first jejunum including the affected lymph node, and second jejunal transfer were performed. Lymph node pathological examination revealed poorly differentiated SCC, compatible with pharyngeal cancer metastasis. After neck dissection and jejunal flap transfer, lymphatic collateral pathways toward the flap's mesenteric lymph node might form. Possibly, hypopharyngeal or oropharyngeal cancer metastasized via this pathway. [ABSTRACT FROM AUTHOR]

The lymphatic vasculature plays a crucial role in fluid clearance and immune responses in peripheral organs by connecting them to distal lymph nodes. Recently, attention has been drawn to the lymphatic vessel network surrounding the brain’s border tissue (Aspelund et al. in J Exp Med 212:991–999, 2015. ; Louveau et al. in Nat Neurosci 21:1380–1391, 2018. ), which guides immune cells in mediating protection against tumors (Song et al. in Nature 577:689–694, 2020. ) and pathogens Li et al. (Nat Neurosci 25:577–587, 2022. ) while also contributing to autoimmunity (Louveau et al. 2018) and neurodegeneration (Da Mesquita et al. in Nature 560:185–191, 2018. ). New studies have highlighted the integral involvement of meningeal lymphatic vessels in neuropathology. However, our limited understanding of spinal cord meningeal lymphatics and immunity hinders efforts to protect and heal the spinal cord from infections, injury, and other immune-mediated diseases. This review aims to provide a comprehensive overview of the state of spinal cord meningeal immunity, highlighting its unique immunologically relevant anatomy, discussing immune cells and lymphatic vasculature, and exploring the potential impact of injuries and inflammatory disorders on this intricate environment. [ABSTRACT FROM AUTHOR]

Background: The chronological pattern of extrahepatic lymphatic vessel progression in the course of chronic liver disease has not been clarified. This study aimed to clarify the chronological changes in lymphatic vessels with liver disease progression. Methods: This was a prospective cross-sectional study that enrolled a total of 199 patients. The maximum diameter of the cisterna chyli (CC) or terminal thoracic duct (tTD) was measured using computed tomography or ultrasonography, respectively. Changes in the maximum diameters of the CC and tTD were evaluated with patients with chronic liver disease as the pilot set (n = 138). Subsequently, we examined whether CC/tTD could be used to re-allocate unclassified patients by the Baveno-VII criteria to appropriately diagnose clinically significant portal hypertension (CSPH) in the pilot and validation sets. Results: In the pilot set, a scatter-plot showed that both CC and tTD were narrowed as terminal features in chronic liver disease after dilation. Because there was a significant correlation between the CC diameter and hepatic venous pressure gradient (r = 0.724) in unclassified patients, the diagnostic value of CC and tTD for CSPH was good (AUC: 0.961 and 0.913, respectively). After re-allocation, 68 and 27 unclassified patients were reduced to 4 and 5 in the pilot and validation sets, respectively. Conclusion: Both the CC and tTD narrow in the course of liver disease after dilation. Moreover, the maximum diameter of the CC and tTD can be used to re-allocate patients who are unclassified according to the Baveno-VII criteria. Clinical trial number: UMIN trial no. 000044857. [ABSTRACT FROM AUTHOR]

Abstract Background UV-induced cutaneous squamous cell carcinoma (cSCC) is one of the most common skin cancers. The constant alterations of the lymphatic-centered immune microenvironment are essential in transforming from photoaging to cSCC. Studying the mechanism will be beneficial for new targets exploration to the early prediction of cSCC. Aims To investigate the dynamic changes and mechanism of the lymphatic-centered immune microenvironment in transforming from photoaging to cSCC induced by ultraviolet irradiation (UVR). Methods TIMER2.0 was used to analyze whether YAP1/VEGFC signaling pathway is involved in lymphangiogenesis in head and neck squamous cell carcinoma (HNSCC). Meanwhile, lymphatic-centered immune microenvironments alterations and the related cumulative survival time were also analyzed. With the accumulated UVR, skin photoaging developed and gradually progressed into actinic keratosis and cSCC on SKH-1 hairless mice. The skin lymphatic-centered immune microenvironment was evaluated at the 0th, 8th, 12th, 16-18th, and 20-24th week of UVR. Skin phenotype was assessed using optical coherence tomography (OCT) and skin image. H&E and Masson’s trichrome staining evaluated epidermis and dermis. The structure of lymphatic vessels (LVs), blood vessels, and different types of T cells were evaluated by immunohistochemistry staining. The expression of Piezo1 whose deletion in adult lymphatics led to substantial valve degeneration, VE-cadherin that maintained the permeability of LVs, and YAP1 were evaluated by immunohistochemistry staining as well. Besides, the drainage function of LVs was assessed by Evans Blue assay in vivo. Results The lymphatic function and immune cell infiltration underwent adaptive changes under continuous UVR. TIMER2.0 analysis indicated that VEGFC genes high expressed in HNSCC. YAP1 gene expression was positive correlated with VEGFC in HNSCC. LV density increased in human cSCC. More LVs in HNSCC were beneficial to prolong the survival time. VEGFC gene overexpression was positive correlated to CD8+T cell infiltration. More CD8A+T cells and CD8B+T cell infiltration in HNSCC extended survival time. When YAP1 gene overexpression and high infiltration of endothelial cells took place simultaneously might prolong the survival time of HNSCC patients. And high infiltration of CD8+T cells prolonged the survival time as well. In animal studies, UVR-induced eight weeks (photoaging) and 16–18 weeks (precancerous) were two turning points. The density of LVs in UV-8w was the least. When photoaged skin developed into AK lesions (UV-16-18w), LV slightly exceeded healthy skin and proliferated sharply in cSCC (UV-20-24w). YAP1 expression was almost consistent with LV but rose after the photoaging stage. The drainage of cSCC mice induced by UVR was better than that of photoaged skin and worse than that of health skin. The dynamic alterations of LVs number, Piezo1 expression, and collagen might be reasons for it. The expression of Piezo1 was in the highest point after 8 weeks of UVR, then gradually descended to the platform. The total T cells increased slowly, but the infiltration of CD4+T cells increased, and CD8+T cells decreased after eight weeks of UVR. The CD8+T cells and CD4+T cells increased sharply in UV-16-18w and UV-20-24w groups. Conclusion The lymphatic-centered immune microenvironment underwent adaptive changes under continuous UVR via regulating YAP1/VEGFC and Piezo1. During the formation of cSCC, there are two turning points, eight weeks (photoaging) and 16–18 weeks (precancerous). YAP1, Piezo1, LVs, and immune cells constantly changed with the skin state induced by UVR. According to these changes the process of cSCC can be identified in advance and intervene timely.

Background: Discrepancies have been noted between the clinical and histologic diagnosis of vascular malformations. Objective: To evaluate the effectiveness of the International Society for Study of Vascular Anomalies (ISSVA) classification in diagnosing benign vascular anomalies based on clinical and (immuno) histologic parameters, focusing on lymphatic differentiation and vascular proliferation. Method: A retrospective study of 121 consecutive patients with benign skin and soft-tissue vascular anomalies located in the head and neck region (pyogenic granulomas and angioma senilis were excluded) by applying multiplex immunohistochemistry staining for lymph vessels (D2-40), endothelial blood vessels, and proliferating cells (Ki67). Clinical and histologic diagnosis was revised after the ISSVA classification. Results: Initially, 64 lesions were diagnosed as tumors and 57 as malformations. Revision diagnosis following the ISSVA classification revealed 27 tumors, 90 malformations (22.2% lymphatic), and 4 non-ISSVA. Immunostaining showed lymphatic differentiation in 24 (19.8%) of 121 cases, of which 20 were malformations. Proliferative activity (Ki67+) was found in 41 (33.8%) of 121 cases, of which 8 were arteriovenous malformations. Limitation: Quality and size of materials (biopsies vs resections) and clinical information. Conclusion: The diagnostic accuracy of combined histologic and clinical approaches for identifying vascular anomalies following the ISSVA classification can be substantially enhanced by incorporating additional immunostaining techniques to evaluate lymphatic differentiation and proliferative activity, particularly in identifying the occurrence of vascular malformations.

Button-like junctions are discontinuous contacts at the border of oak-leaf-shaped endothelial cells of initial lymphatic vessels. These junctions are distinctively different from continuous zipper-like junctions that create the endothelial barrier in collecting lymphatics and blood vessels. Button junctions are point contacts, spaced about 3 µm apart, that border valve-like openings where fluid and immune cells enter lymphatics. In intestinal villi, openings between button junctions in lacteals also serve as entry routes for chylomicrons. Like zipper junctions that join endothelial cells, buttons consist of adherens junction proteins (VE-cadherin) and tight junction proteins (claudin-5, occludin, and others). Buttons in lymphatics form from zipper junctions during embryonic development, can convert into zippers in disease or after experimental genetic or pharmacological manipulation, and can revert back to buttons with treatment. Multiple signaling pathways and local microenvironmental factors have been found to contribute to button junction plasticity and could serve as therapeutic targets in pathological conditions ranging from pulmonary edema to obesity.

Changes in blood vessels and lymphatics in health and disease are easier to understand and interpret when studied microscopically in three dimensions. The mouse trachea is a simple, yet powerful, and versatile model system in which to achieve this. We describe practical immunohistochemical methods for fluorescence and confocal microscopy of wholemounts of the mouse trachea to achieve this purpose in which the entire vasculature can be visualized from the organ level to the cellular and subcellular level. Blood vessels and lymphatics have highly stereotyped vascular architectures that repeat in arcades between the tracheal cartilages. Arterioles, capillaries, and venules can be easily identified for the blood vessels, while the lymphatics consist of initial lymphatics and collecting lymphatics. Even small abnormalities in either blood vessels or lymphatics can be noticed and evaluated in three dimensions. We and others have used the mouse trachea for examining in situ angiogenesis and lymphangiogenesis, vascular development and regression, vessel patency, differences in transgenic mice, and pathological changes, such as increased vascular permeability induced by inflammatory mediators.

Background Little is known about the distribution of posaconazole in brain tissue and CSF. We therefore analysed trough concentrations of posaconazole in paediatric leukaemia patients in non-inflamed CSF. Patients and methods The study included paediatric patients <18 years of age with acute leukaemia in remission who underwent repeat therapeutic lumbar punctures as part of their anti-leukaemia treatment. CSF and blood were obtained 20–24 h after dosing, and posaconazole was measured by LC-MS/MS. Results Six patients (median age: 10 years; range, 6–14) with acute lymphatic (three) or acute myeloid (three) leukaemia were included who received posaconazole gastroresistant tablets at weight-banded doses (five) or the oral solution (one). In contrast to 14 control samples, posaconazole was detectable in all 11 samples of treated patients. CSF concentrations ranged from 8.3 to 42 ng/mL with a median CSF concentration of 13.6 ng/mL. Concurrent serum concentrations were between 965 and 5177 ng/mL with a median of 1716 ng/mL. Conclusions Trough concentrations of posaconazole in the CSF after systemic administration were low but detectable in all subjects. Concurrent serum concentrations were in the target range for prophylaxis and treatment in 100% and 90%, respectively. [ABSTRACT FROM AUTHOR]

Abstract Alzheimer’s disease (AD) is an aging-related form of dementia associated with the accumulation of pathological aggregates of amyloid beta and neurofibrillary tangles in the brain. These phenomena are accompanied by exacerbated inflammation and marked neuronal loss, which altogether contribute to accelerated cognitive decline. The multifactorial nature of AD, allied to our still limited knowledge of its etiology and pathophysiology, have lessened our capacity to develop effective treatments for AD patients. Over the last few decades, genome wide association studies and biomarker development, alongside mechanistic experiments involving animal models, have identified different immune components that play key roles in the modulation of brain pathology in AD, affecting its progression and severity. As we will relay in this review, much of the recent efforts have been directed to better understanding the role of brain innate immunity, and particularly of microglia. However, and despite the lack of diversity within brain resident immune cells, the brain border tissues, especially the meninges, harbour a considerable number of different types and subtypes of adaptive and innate immune cells. Alongside microglia, which have taken the centre stage as important players in AD research, there is new and exciting evidence pointing to adaptive immune cells, namely T and B cells found in the brain and its meninges, as important modulators of neuroinflammation and neuronal (dys)function in AD. Importantly, a genuine and functional lymphatic vascular network is present around the brain in the outermost meningeal layer, the dura. The meningeal lymphatics are directly connected to the peripheral lymphatic system in different mammalian species, including humans, and play a crucial role in preserving a “healthy” immune surveillance of the CNS, by shaping immune responses, not only locally at the meninges, but also at the level of the brain tissue. In this review, we will provide a comprehensive view on our current knowledge about the meningeal lymphatic vasculature, emphasizing its described roles in modulating CNS fluid and macromolecule drainage, meningeal and brain immunity, as well as glial and neuronal function in aging and in AD.

Shun-Shun Wang,1,2,&ast; Xin-Xu Zhu,1,2,&ast; Xin-Yi Wu,1,2,&ast; Wen-Wu Zhang,1,2 Yang-Dong Ding,1,2 Sheng-Wei Jin,1,2 Pu-Hong Zhang1,2 1Department of Anesthesia and Critical Care, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Zhejiang, People’s Republic of China; 2Key Laboratory of Anesthesiology of Zhejiang Province, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Zhejiang, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Sheng-Wei Jin; Pu-Hong Zhang, Department of Anesthesia and Critical Care, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, 109 Xueyuan Road, Wenzhou, Zhejiang Province, 325027, People’s Republic of China, Email jinshengwei69@163.com; drzhangpuhong@wmu.edu.cnAbstract: Physiological activity cannot be regulated without the blood and lymphatic vasculatures, which play complementary roles in maintaining the body’s homeostasis and immune responses. Inflammation is the body’s initial response to pathological injury and is responsible for protecting the body, removing damaged tissues, and restoring and maintaining homeostasis in the body. A growing number of researches have shown that blood and lymphatic vessels play an essential role in a variety of inflammatory diseases. In the inflammatory state, the permeability of blood vessels and lymphatic vessels is altered, and angiogenesis and lymphangiogenesis subsequently occur. The blood vascular and lymphatic vascular systems interact to determine the development or resolution of inflammation. In this review, we discuss the changes that occur in the blood vascular and lymphatic vascular systems of several organs during inflammation, describe the different scenarios of angiogenesis and lymphangiogenesis at different sites of inflammation, and demonstrate the prospect of targeting the blood vasculature and lymphatic vasculature systems to limit the development of inflammation and promote the resolution of inflammation in inflammatory diseases.Keywords: inflammation, blood vessels, lymphatic vessels, lymphangiogenesis, angiogenesis

Laparoscopic donor nephrectomy (LDN) is increasingly popular because of its advantages over open surgery. Chyle leak after donor nephrectomy is a rare but potentially lethal complication if not treated appropriately. We describe a case of a 43-year-old female patient with no remarkable history who presented a chyle leak on day 2 after right transperitoneal LDN. Since conservative treatment failed, the patient underwent magnetic resonance imaging (MRI) and intranodal lipiodol lymphangiography, which confirmed the chyle leak from the right lumbar lymph trunk into the right renal fossa. The chyle leak was percutaneously embolized twice, on postoperative day (POD) 5 and POD 10, by a mixture of N-butyl-2-cyanoacrylate and lipiodol. The drainage fluid decreased significantly after the second embolization. The subhepatic drainage tube was withdrawn on POD 14, and the patient was discharged on POD 17. MRI lymphangiography and intranodal lipiodol lymphangiography effectively identified the chyle leak point. Percutaneous embolization seems to be a safe, effective method for treating high-output chyle leaks.

Abstract Lymphatic vessels are actively involved in the recovery process of inflamed tissues. However, the changes in intramuscular lymphatic vessels during inflammation caused by skeletal muscle injury remain unclear. Therefore, the purpose of this study was to clarify the changes in lymphatic vessels after skeletal muscle injury. The left tibialis anterior muscles of male mice were subjected to lengthening contractions (LC) for inducing skeletal muscle injury, and samples were collected on Days 2, 4, and 7 for examining changes in both the skeletal muscles and intramuscular lymphatic vessels. With hematoxylin–eosin staining, the inflammatory response was observed in myofibers on Days 2 and 4 after LC, whereas regeneration of myofibers was found on Day 7 after LC. The number and area of intramuscular lymphatic vessels analyzed by immunohistochemical staining with an antibody against lymphatic vessel endothelial hyaluronan receptor 1 were significantly increased only on Day 4 after LC. Based on the abovementioned results, intramuscular lymphatic vessels undergo morphological changes such as increase under the state of muscle inflammation. This study demonstrated that the morphology of intramuscular lymphatic vessels undergoes significant changes during the initial recovery phase following skeletal muscle injury.