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PURPOSE OF REVIEW: This review delves into recent advancements in understanding generalized and organ-specific lymphatic development. It emphasizes the distinct characteristics and critical anomalies that can impair lymphatic function. By exploring developmental mechanisms, the review seeks to illuminate the profound impact of lymphatic malformations on overall health and disease progression. RECENT FINDINGS: The introduction of genome sequencing, single-cell transcriptomic analysis, and advanced imaging technologies has significantly enhanced our ability to identify and characterize developmental defects within the lymphatic system. As a result, a wide range of lymphatic anomalies have been uncovered, spanning from congenital abnormalities present at birth to conditions that can become life-threatening in adulthood. Additionally, recent research highlights the heterogeneity of lymphatics, revealing organ-specific developmental pathways, unique molecular markers, and specialized physiological functions specific to each organ. A deeper understanding of the unique characteristics of lymphatic cell populations in an organ-specific context is essential for guiding future research into lymphatic disease processes. An integrated approach to translational research could revolutionize personalized medicine, where treatments are precisely tailored to individual lymphatic profiles, enhancing effectiveness and minimizing side effects.
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Lymphatic endothelial cells (LECs) line lymphatic vessels, which play an important role in the transport of lymph fluid throughout the human body. An organized lymphatic network develops via a process termed "lymphangiogenesis." During development, LECs respond to growth factor signaling to initiate the formation of a primary lymphatic vascular network. These LECs display a unique metabolic profile, preferring to undergo glycolysis even in the presence of oxygen. In addition to their reliance on glycolysis, LECs utilize other metabolic pathways such as fatty acid ß-oxidation, ketone body oxidation, mitochondrial respiration, and lipid droplet autophagy to support lymphangiogenesis. This review summarizes the current understanding of metabolic regulation of lymphangiogenesis. Moreover, it highlights how LEC metabolism is implicated in various pathological conditions.
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Recent studies have described the importance of lymphatics in numerous organ-specific physiological and pathological processes. The role of meningeal lymphatics in various neurological and cerebrovascular diseases has been suggested. It has also been shown that these structures develop postnatally and are altered by aging and that the vascular endothelial growth factor C (VEGFC)/ vascular endothelial growth factor receptor 3 (VEGFR3) signaling plays an essential role in the development and maintenance of them. However, the molecular mechanisms governing the development and maintenance of meningeal lymphatics are still poorly characterized. Recent in vitro cell culture-based experiments, and in vivo studies in zebrafish and mouse skin suggest that collagen and calcium binding EGF domains 1 (CCBE1) is involved in the processing of VEGFC. However, the organ-specific role of CCBE1 in developmental lymphangiogenesis and maintenance of lymphatics remains unclear. Here, we aimed to investigate the organ-specific functions of CCBE1 in developmental lymphangiogenesis and maintenance of meningeal lymphatics during aging. We demonstrate that inducible deletion of CCBE1 leads to impaired postnatal development of the meningeal lymphatics and decreased macromolecule drainage to deep cervical lymph nodes. The structural integrity and density of meningeal lymphatics are gradually altered during aging. Furthermore, the meningeal lymphatic structures in adults showed regression after inducible CCBE1 deletion. Collectively, our results indicate the importance of CCBE1-dependent mechanisms not only in the development, but also in the prevention of the age-related regression of meningeal lymphatics. Therefore, targeting CCBE1 may be a good therapeutic strategy to prevent age-related degeneration of meningeal lymphatics.
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Vasos Linfáticos , Pez Cebra , Animales , Ratones , Colágeno Tipo I/metabolismo , Linfangiogénesis , Vasos Linfáticos/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Factor C de Crecimiento Endotelial Vascular/genética , Factor C de Crecimiento Endotelial Vascular/metabolismo , Pez Cebra/metabolismoRESUMEN
Mutations in the transcription factor-coding gene SOX18, the growth factor-coding gene VEGFC and its receptor-coding gene VEGFR3/FLT4 cause primary lymphedema in humans. In mammals, SOX18, together with COUP-TFII/NR2F2, activates the expression of Prox1, a master regulator in lymphatic identity and development. Knockdown studies have also suggested an involvement of Sox18, Coup-tfII/Nr2f2, and Prox1 in zebrafish lymphatic development. Mutants in the corresponding genes initially failed to recapitulate the lymphatic defects observed in morphants. In this paper, we describe a novel zebrafish sox18 mutant allele, sa12315, which behaves as a null. The formation of the lymphatic thoracic duct is affected in sox18 homozygous mutants, but defects are milder in both zygotic and maternal-zygotic sox18 mutants than in sox18 morphants. Remarkably, in sox18 mutants, the expression of the closely related sox7 gene is elevated where lymphatic precursors arise. Sox7 could thus mask the absence of a functional Sox18 protein and account for the mild lymphatic phenotype in sox18 mutants, as shown in mice. Partial knockdown of vegfc exacerbates lymphatic defects in sox18 mutants, making them visible in heterozygotes. Our data thus reinforce the genetic interaction between Sox18 and Vegfc in lymphatic development, previously suggested by knockdown studies, and highlight the ability of Sox7 to compensate for Sox18 lymphatic dysfunction.
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Vasos Linfáticos , Factores de Transcripción SOXF , Proteínas de Pez Cebra , Pez Cebra , Animales , Humanos , Ratones , Vasos Linfáticos/metabolismo , Transducción de Señal/fisiología , Factores de Transcripción SOXF/genética , Factores de Transcripción SOXF/metabolismo , Factores de Transcripción/metabolismo , Pez Cebra/genética , Pez Cebra/metabolismo , Proteínas de Pez Cebra/metabolismoRESUMEN
Intestinal lacteals are essential lymphatic channels for absorption and transport of dietary lipids and drive the pathogenesis of debilitating metabolic diseases. However, organ-specific mechanisms linking lymphatic dysfunction to disease etiology remain largely unknown. In this study, we uncover an intestinal lymphatic program that is linked to the left-right (LR) asymmetric transcription factor Pitx2. We show that deletion of the asymmetric Pitx2 enhancer ASE alters normal lacteal development through the lacteal-associated contractile smooth muscle lineage. ASE deletion leads to abnormal muscle morphogenesis induced by oxidative stress, resulting in impaired lacteal extension and defective lymphatic system-dependent lipid transport. Surprisingly, activation of lymphatic system-independent trafficking directs dietary lipids from the gut directly to the liver, causing diet-induced fatty liver disease. Our study reveals the molecular mechanism linking gut lymphatic function to the earliest symmetry-breaking Pitx2 and highlights the important relationship between intestinal lymphangiogenesis and the gut-liver axis.
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Grasas de la Dieta/metabolismo , Proteínas de Homeodominio/metabolismo , Intestinos/metabolismo , Factores de Transcripción/metabolismo , Animales , Transporte Biológico , Duodeno/metabolismo , Femenino , Proteínas de Homeodominio/genética , Mucosa Intestinal/metabolismo , Metabolismo de los Lípidos/fisiología , Lípidos/fisiología , Linfangiogénesis/fisiología , Vasos Linfáticos/metabolismo , Masculino , Ratones , Transducción de Señal , Factores de Transcripción/genética , Proteína del Homeodomínio PITX2RESUMEN
Microenvironmental signals produced during development or inflammation stimulate lymphatic endothelial cells to undergo lymphangiogenesis, in which they sprout, proliferate, and migrate to expand the vascular network. Many cell types detect changes in extracellular conditions via primary cilia, microtubule-based cellular protrusions that house specialized membrane receptors and signaling complexes. Primary cilia are critical for receipt of extracellular cues from both ligand-receptor pathways and physical forces such as fluid shear stress. Here, we report the presence of primary cilia on immortalized mouse and primary adult human dermal lymphatic endothelial cells in vitro and on both luminal and abluminal domains of mouse corneal, skin, and mesenteric lymphatic vessels in vivo. The purpose of this study was to determine the effects of disrupting primary cilia on lymphatic vessel patterning during development and inflammation. Intraflagellar transport protein 20 (IFT20) is part of the transport machinery required for ciliary assembly and function. To disrupt primary ciliary signaling, we generated global and lymphatic endothelium-specific IFT20 knockout mouse models and used immunofluorescence microscopy to quantify changes in lymphatic vessel patterning at E16.5 and in adult suture-mediated corneal lymphangiogenesis. Loss of IFT20 during development resulted in edema, increased and more variable lymphatic vessel caliber and branching, as well as red blood cell-filled lymphatics. We used a corneal suture model to determine ciliation status of lymphatic vessels during acute, recurrent, and tumor-associated inflammatory reactions and wound healing. Primary cilia were present on corneal lymphatics during all of the mechanistically distinct lymphatic patterning events of the model and assembled on lymphatic endothelial cells residing at the limbus, stalk, and vessel tip. Lymphatic-specific deletion of IFT20 cell-autonomously exacerbated acute corneal lymphangiogenesis resulting in increased lymphatic vessel density and branching. These data are the first functional studies of primary cilia on lymphatic endothelial cells and reveal a new dimension in regulation of lymphatic vascular biology.
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Our understanding of the function and development of the lymphatic system is expanding rapidly due to the identification of specific molecular markers and the availability of novel genetic approaches. In connection, it has been demonstrated that mechanical forces contribute to the endothelial cell fate commitment and play a critical role in influencing lymphatic endothelial cell shape and alignment by promoting sprouting, development, maturation of the lymphatic network, and coordinating lymphatic valve morphogenesis and the stabilization of lymphatic valves. However, the mechanosignaling and mechanotransduction pathways involved in these processes are poorly understood. Here, we provide an overview of the impact of mechanical forces on lymphatics and summarize the current understanding of the molecular mechanisms involved in the mechanosensation and mechanotransduction by lymphatic endothelial cells. We also discuss how these mechanosensitive pathways affect endothelial cell fate and regulate lymphatic development and function. A better understanding of these mechanisms may provide a deeper insight into the pathophysiology of various diseases associated with impaired lymphatic function, such as lymphedema and may eventually lead to the discovery of novel therapeutic targets for these conditions.
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Linfangiogénesis/genética , Sistema Linfático/metabolismo , Mecanotransducción Celular/genética , Morfogénesis/genética , Células Endoteliales/metabolismo , Humanos , Sistema Linfático/crecimiento & desarrollo , Vasos Linfáticos/metabolismo , Estrés MecánicoRESUMEN
A majority of lymphatic valves tend to form in proximity to vessel junctions, and it is often proposed that disturbed flow at junctions creates oscillating shear stress that leads to accumulation of transcription factors which bring about valvogenesis at these sites. In images of networks of dorsal skin lymphatics from embryonic mice (day E16), we compared simulated fluid flow patterns and observed distributions of the transcription factor Prox1, which is implicated in valve formation. Because of creeping-flow conditions, flow across vessel junctions was not 'disturbed', and within a given vessel, shear stress varied inversely with local conduit width. Prox1 concentration was indeed localised to vessel end-regions, but over three networks was not consistently correlated with the vessel normalised-distance distribution of either fluid shear stress or shear-stress axial gradient. These findings do not support the presently accepted mechanism for the role of flow in valve localisation.
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Vasos Linfáticos , Animales , Ratones , Estrés MecánicoRESUMEN
The lymphatic vascular system acts as the major transportation highway of tissue fluids, and its activation or impairment is associated with a wide range of diseases. There has been increasing interest in understanding the mechanisms that control lymphatic vessel formation (lymphangiogenesis) and function in development and disease. Here, we discuss recent insights into new players whose identification has contributed to deciphering the lymphatic regulatory code. We reveal how lymphatic endothelial cells, the building blocks of lymphatic vessels, utilize their transcriptional, post-transcriptional, and epigenetic portfolio to commit to and maintain their vascular lineage identity and function, with a particular focus on development.
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Epigénesis Genética , Proteínas de Homeodominio/metabolismo , Vasos Linfáticos/metabolismo , ARN no Traducido/metabolismo , Transcripción Genética , Proteínas Supresoras de Tumor/metabolismo , Animales , Humanos , Vasos Linfáticos/anatomía & histología , Vasos Linfáticos/embriología , MicroARNs/genética , MicroARNs/metabolismo , ARN no Traducido/genéticaRESUMEN
Non-coding RNAs (ncRNAs), which do not encode proteins, have pivotal roles in manipulating gene expression in development, physiology, and pathology. Emerging data have shown that ncRNAs can regulate lymphangiogenesis, which refers to lymphatics deriving from preexisting vessels, becomes established during embryogenesis, and has a close relationship with pathological conditions such as lymphatic developmental diseases, inflammation, and cancer. This review summarizes the molecular mechanisms of lymphangiogenesis in lymphatic development, inflammation and cancer metastasis, and discusses ncRNAs' regulatory effects on them. Therapeutic targets with regard to lymphangiogenesis are also discussed.
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The lymphatic system comprises blind-ended tubes that collect interstitial fluid and return it to the circulatory system. In mammals, unidirectional lymphatic flow is driven by muscle contraction working in conjunction with valves. Accordingly, defective lymphatic valve morphogenesis results in backflow leading to edema. In fish species, studies dating to the 18th century failed to identify lymphatic valves, a precedent that currently persists, raising the question of whether the zebrafish could be used to study the development of these structures. Here, we provide functional and morphological evidence of valves in the zebrafish lymphatic system. Electron microscopy revealed valve ultrastructure similar to mammals, while live imaging using transgenic lines identified the developmental origins of lymphatic valve progenitors. Zebrafish embryos bearing mutations in genes required for mammalian valve morphogenesis show defective lymphatic valve formation and edema. Together, our observations provide a foundation from which to further investigate lymphatic valve formation in zebrafish.
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Vasos Linfáticos/embriología , Pez Cebra/embriología , Animales , Secuencia de Bases , Embrión no Mamífero/metabolismo , Células Progenitoras Endoteliales/metabolismo , Células Progenitoras Endoteliales/ultraestructura , Cara/anatomía & histología , Regulación del Desarrollo de la Expresión Génica , Proteínas Fluorescentes Verdes/metabolismo , Imagenología Tridimensional , Larva/anatomía & histología , Larva/metabolismo , Vasos Linfáticos/anatomía & histología , Vasos Linfáticos/ultraestructura , Ratones , Morfogénesis , Factores de Transcripción/metabolismo , Pez Cebra/genética , Proteínas de Pez Cebra/metabolismoRESUMEN
The post-transcriptional mechanisms contributing to molecular regulation of developmental lymphangiogenesis and lymphatic network assembly are not well understood. MicroRNAs are important post-transcriptional regulators during development. Here, we use high throughput small RNA sequencing to identify miR-204, a highly conserved microRNA dramatically enriched in lymphatic vs. blood endothelial cells in human and zebrafish. Suppressing miR-204 leads to loss of lymphatic vessels while endothelial overproduction of miR-204 accelerates lymphatic vessel formation, suggesting a critical positive role for this microRNA during developmental lymphangiogenesis. We also identify the NFATC1 transcription factor as a key miR-204 target in human and zebrafish, and show that NFATC1 suppression leads to lymphatic hyperplasia. The loss of lymphatics caused by miR-204 deficiency can be largely rescued by either endothelial autonomous expression of miR-204 or by suppression of NFATC1. Together, our results highlight a miR-204/NFATC1 molecular regulatory axis required for proper lymphatic development.
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Regulación del Desarrollo de la Expresión Génica , Linfangiogénesis , MicroARNs/metabolismo , Factores de Transcripción NFATC/metabolismo , Animales , Células Endoteliales/fisiología , Humanos , Pez CebraRESUMEN
Hippocratic Corpus, a collection of Greek medical literature, described the functional anatomy of the lymphatic system in the fifth century B.C. Subsequent studies in cadavers and surgical patients firmly established that lymphatic vessels drain extravasated interstitial fluid, also known as lymph, into the venous system at the bilateral lymphovenous junctions. Recent advances revealed that lymphovenous valves and platelet-mediated hemostasis at the lymphovenous junctions maintain life-long separation of the blood and lymphatic vascular systems. Here, we review murine models that exhibit failure of blood-lymph separation to highlight the novel mechanisms and molecular targets for the modulation of lymphatic disorders. Specifically, we focus on the transcription factors, cofactors, and signaling pathways that regulate lymphovenous valve development and platelet-mediated lymphovenous hemostasis, which cooperate to maintain blood-lymph separation.
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Plaquetas/metabolismo , Linfa/metabolismo , Linfangiogénesis/genética , Vasos Linfáticos/metabolismo , Animales , Regulación del Desarrollo de la Expresión Génica , Hemostasis/genética , Humanos , Vasos Linfáticos/embriología , Ratones , Transducción de Señal/genéticaRESUMEN
Exogenous cues involved in the regulation of the initial steps of lymphatic endothelial development remain largely unknown. We have used an in vitro model based on the co-culture of vascular precursors derived from mouse embryonic stem cell (ESC) differentiation and OP9 stromal cells to examine the first steps of lymphatic specification and expansion. We found that bone morphogenetic protein 9 (BMP9) induced a dose-dependent biphasic effect on ESC-derived vascular precursors. At low concentrations, below 1 ng/mL, BMP9 expands the LYVE-1-positive lymphatic progeny and activates the calcineurin phosphatase/NFATc1 signaling pathway. In contrast, higher BMP9 concentrations preferentially enhance the formation of LYVE-1-negative endothelial cells. This effect results from an OP9 stromal cell-mediated VEGF-A secretion. RNA-silencing experiments indicate specific involvement of ALK1 and ALK2 receptors in these different BMP9 responses. BMP9 at low concentrations may be a useful tool to generate lymphatic endothelial cells from stem cells for cell-replacement strategies.
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Diferenciación Celular , Células Endoteliales/citología , Factor 2 de Diferenciación de Crecimiento/farmacología , Linfangiogénesis , Células Madre Embrionarias de Ratones/citología , Receptores de Activinas Tipo I/genética , Receptores de Activinas Tipo I/metabolismo , Receptores de Activinas Tipo II/genética , Receptores de Activinas Tipo II/metabolismo , Animales , Calcineurina/metabolismo , Proliferación Celular , Células Cultivadas , Células Endoteliales/metabolismo , Humanos , Vasos Linfáticos/citología , Ratones , Células Madre Embrionarias de Ratones/efectos de los fármacos , Células Madre Embrionarias de Ratones/metabolismo , Factores de Transcripción NFATC/genética , Factores de Transcripción NFATC/metabolismo , Factor A de Crecimiento Endotelial Vascular/genética , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
During embryonic development, lymphatic endothelial cells (LECs) differentiate from venous endothelial cells (VECs), a process that is tightly regulated by several genetic signals. While the aquatic zebrafish model is regularly used for studying lymphangiogenesis and offers the unique advantage of time-lapse video-imaging of lymphatic development, some aspects of lymphatic development in this model differ from those in the mouse. It therefore remained to be determined whether fatty acid ß-oxidation (FAO), which we showed to regulate lymphatic formation in the mouse, also co-determines lymphatic development in this aquatic model. Here, we took advantage of the power of the zebrafish embryo model to visualize the earliest steps of lymphatic development through time-lapse video-imaging. By targeting zebrafish isoforms of carnitine palmitoyltransferase 1a (cpt1a), a rate controlling enzyme of FAO, with multiple morpholinos, we demonstrate that reducing CPT1A levels and FAO flux during zebrafish development impairs lymphangiogenic secondary sprouting, the initiation of lymphatic development in the zebrafish trunk, and the formation of the first lymphatic structures. These findings not only show evolutionary conservation of the importance of FAO for lymphatic development, but also suggest a role for FAO in co-regulating the process of VEC-to-LEC differentiation in zebrafish in vivo.
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Ácidos Grasos/metabolismo , Vasos Linfáticos/embriología , Vasos Linfáticos/metabolismo , Pez Cebra/embriología , Pez Cebra/metabolismo , Animales , Animales Modificados Genéticamente , Carnitina O-Palmitoiltransferasa/antagonistas & inhibidores , Carnitina O-Palmitoiltransferasa/genética , Carnitina O-Palmitoiltransferasa/metabolismo , Diferenciación Celular , Células Endoteliales/citología , Células Endoteliales/metabolismo , Marcación de Gen , Linfangiogénesis/genética , Linfangiogénesis/fisiología , Modelos Animales , Oxidación-Reducción , Imagen de Lapso de Tiempo , Pez Cebra/genética , Proteínas de Pez Cebra/antagonistas & inhibidores , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismoRESUMEN
A critical event in embryo development is the proper formation of the vascular system, of which the hepatobiliary system plays a pivotal role. This has led researchers to use transgenic mice to identify the critical steps involved in developmental disorders associated with the hepatobiliary vascular system. Vascular development is dependent upon normal vasculogenesis, angiogenesis, and the transformation of vessels into their adult counterparts. Any alteration in vascular development has the potential to cause deformities or embryonic death. Numerous publications describe specific stages of vascular development relating to various organs, but a single resource detailing the stage-by-stage development of the vasculature pertaining to the hepatobiliary system has not been available. This comprehensive histology atlas provides hematoxylin & eosin and immunohistochemical-stained sections of the developing mouse blood and lymphatic vasculature with emphasis on the hepatobiliary system between embryonic days (E) 11.5-18.5 and the early postnatal period. Additionally, this atlas includes a 3-dimensional video representation of the E18.5 mouse venous vasculature. One of the most noteworthy findings of this atlas is the identification of the portal sinus within the mouse, which has been erroneously misinterpreted as the ductus venosus in previous publications. Although the primary purpose of this atlas is to identify normal hepatobiliary vascular development, potential embryonic abnormalities are also described.
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Sistema Biliar/embriología , Vasos Sanguíneos/embriología , Hígado/embriología , Sistema Linfático/embriología , Anatomía Artística , Animales , Atlas como Asunto , Embrión de Mamíferos , Desarrollo Embrionario , Ratones , Ratones TransgénicosRESUMEN
Lymphatic vessels are present throughout the entire body in all mammals and function to regulate tissue fluid balance, lipid transport and survey the immune system. Despite the presence of an extensive lymphatic plexus within the heart, until recently the importance of the cardiac lymphatic vasculature and its origins were unknown. Several studies have described the basic anatomy of the developing cardiac lymphatic vasculature and more recently the detailed development of the murine cardiac lymphatics has been documented, with important insight into their cellular sources during embryogenesis. In this review we initially describe the development of systemic lymphatic vasculature, to provide the background for a comparative description of the spatiotemporal development of the cardiac lymphatic vessels, including detail of both canonical, typically venous, and noncanonical (hemogenic endothelium) cellular sources. Subsequently, we address the response of the cardiac lymphatic network to myocardial infarction (heart attack) and the therapeutic potential of targeting cardiac lymphangiogenesis.
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Corazón/anatomía & histología , Vasos Linfáticos/anatomía & histología , Animales , Desarrollo Embrionario , Corazón/embriología , Vasos Linfáticos/embriología , Vasos Linfáticos/fisiologíaRESUMEN
The lymphatic vasculature plays an essential role in the maintenance of tissue interstitial fluid balance and in the immune response. After capture of fluids, proteins and antigens by lymphatic capillaries, lymphatic collecting vessels ensure lymph transport. An important component to avoid lymph backflow and to allow a unidirectional flow is the presence of intraluminal valves. Defects in the function of collecting vessels lead to lymphedema. Several important factors and signaling pathways involved in lymphatic collecting vessel maturation and valve morphogenesis have now been discovered. The present review summarizes the current knowledge about the key steps of lymphatic collecting vessel development and maturation and focuses on the regulatory mechanisms involved in lymphatic valve formation.
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Linfangiogénesis/fisiología , Vasos Linfáticos/embriología , Animales , Tipificación del Cuerpo , Vasos Linfáticos/metabolismo , Linfedema , Ratones , Modelos Biológicos , Morfogénesis/fisiología , Transducción de SeñalRESUMEN
Nuchal translucency (NT) is a hypo-echoic region of subcutaneous fluid accumulation in the posterior neck at the level of the cervical spine between the skin and soft tissues found at 10-14 weeks gestation. This ultrasound finding is important because increased NT measurements place the fetus at increased risk for chromosomal and structural abnormalities. It is a fascinating phenomenon that displays the intersection of anatomy, development, and imaging. In addition, with the ever increasing use of ultrasound in anatomy, NT is a readily demonstrable example of how important ultrasound has become to the practice of medicine. Articles on NT were obtained from OVID database and reviewed for their contribution to an understanding of the anatomical basis of NT. Whereas it is well established that the ultrasound finding of increased NT is a sensitive marker for Trisomy 21 at 10-14 weeks gestation, why this phenomena occurs has yet to be explained. The basis of nuchal edema is most likely multifactorial, a combination of delayed or disturbed lymphangiogenesis, cardiac and vascular abnormalities, and abnormal extracellular matrix components. Further research on the development of the fetal head and neck related to lymphatic development and fluid regulation during 8-14 weeks gestation will enable a greater understanding of how and why increased NT occurs compared to what is currently known. This could lead to early intervention to manage some of the repercussions of Trisomy 21 and other abnormalities related to NT.
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Síndrome de Down/diagnóstico por imagen , Feto/anatomía & histología , Edad Gestacional , Cuello/diagnóstico por imagen , Medida de Translucencia Nucal , Síndrome de Down/embriología , Femenino , Humanos , Cuello/anatomía & histología , Cuello/embriología , Embarazo , Primer Trimestre del EmbarazoRESUMEN
PURPOSE: Many infants develop a postsurgical chylothorax after diaphragmatic hernia repair. The pathogenesis remains elusive but may be owing to dysfunctional lymphatic development. This study characterizes pulmonary lymphatic development in the nitrofen mouse model of CDH. METHODS: CD1 pregnant mice were fed nitrofen/bisdiamine (N/B) or olive oil at E8.5. At E14.5 and E15.5, lung buds were categorized by phenotype: normal, N/B without CDH (N/B - CDH), or N/B with CDH (N/B+CDH). Anti-CD31 was used to localize all endothelial cells, while anti-LYVE-1 was used to identify lymphatic endothelial cells in lung buds using immunofluorescence. Differential protein expression of lymphatic-specific markers was analyzed. RESULTS: Lymphatic endothelial cells localized to the mesenchyme surrounding the airway epithelium at E15.5. CD31 and LYVE-1 colocalization identified lymphatic endothelial cells. LYVE-1 expression was upregulated in N/B+CDH lung buds in comparison to N/B - CDH and normal lung buds by immunofluorescence. Western blotting shows that VEGF-D, LYVE-1, Prox-1, and VEGFR-3 expression was upregulated in N/B+CDH lung buds in comparison to N/B - CDH or control lung buds at E14.5. CONCLUSIONS: Lung lymphatics are hyperplastic in N/B+CDH. Upregulation of lymphatic-specific genes suggests that lymphatic hyperplasia plays an important role in dysfunctional lung lymphatic development in the nitrofen mouse model of CDH.