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Background: Lymphangiogenesis is believed to be a protective response in the setting of multiple forms of kidney injury and mitigates the progression of interstitial fibrosis. To augment this protective response, promoting kidney lymphangiogenesis is being investigated as a potential treatment to slow the progression of kidney disease. As injury-related lymphangiogenesis is driven by signaling from the receptor VEGFR3 (vascular endothelial growth factor receptor 3) in response to the cognate growth factor VEGF (vascular endothelial growth factor)-C released by tubular epithelial cells, this signaling pathway is a candidate for future kidney therapeutics. However, the consequences to kidney development and function to targeting this signaling pathway remain poorly defined., Methods: We generated a new mouse model expressing Vegfc under regulation of the nephron progenitor Six2Cre driver strain ( Six2Vegfc ). Mice underwent a detailed phenotypic evaluation. Whole kidneys were processed for histology and 3-dimensional imaging., Results: Six2Vegfc mice had reduced body weight and kidney function compared with littermate controls. Six2Vegfc kidneys demonstrated large peripelvic fluid-filled lesions with distortion of the pelvicalcyceal system which progressed in severity with age. Three-dimensional imaging showed a 3-fold increase in total cortical vascular density. Histology confirmed a substantial increase in LYVE1+ (lymphatic vessel endothelial hyaluronan receptor-1)/PDPN+ (podoplanin)/VEGFR3+ lymphatic capillaries extending alongside EMCN+ (endomucin) peritubular capillaries. There was no change in EMCN+ peritubular capillary density., Conclusions: Kidney lymphatic density was robustly increased in the Six2Vegfc mice. There were no changes in peritubular blood capillary density despite these endothelial cells also expressing VEGFR3. The model resulted in malformation of the lymphatic hilar plexus, resulting in severe hydronephrosis that resembled a human condition termed renal lymphangiectasia. This study defines the vascular consequences of augmenting VEGFC signaling during kidney development and provides new insight into human renal lymphatic malformations., Competing Interests: S.E. Quaggin holds patents related to therapeutic targeting of the ANGPT-TEK (angiopoeitin-TEK receptor tyrosine kinase or Tie2) pathway in ocular hypertension and glaucoma and vascular diseases and owns stock in Mannin Research. S.E. Quaggin also receives consulting fees from AstraZeneca, Janssen, the Lowy Medical Research Foundation, Novartis, Pfizer, Janssen, Unity Biotechnology, and Roche/Genentech. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The other authors report no conflicts.

Kaposiform lymphangiomatosis (KLA) is a vascular anomaly featuring lymphatic expansion. It has no known cause, no effective treatment, and is associated with high morbidity. Proliferative cells from 3 KLA patient lesions were characterized relative to adiopose-derived mesenchyme stem cells (ADSCs) and cells derived from a patient with the related disease kaposiform hemangioendothelioma (KHE). KLA cells variably expressed markers of mesenchyme stem cells (CD73, CD90, CD105, CD146) and lacked endothelial cell markers (CD31, CD34) as determined by flow cytometry. They expressed markers of vascular pericytes (neural/glial antigen 2, alpha-smooth muscle actin, platelet-derived growth factor-beta receptor, and CXCL12) as determined by quantitative reverse transcription polymerase chain reaction. Lesion cells transcribed vascular markers VEGFC and VEGFD, as well as VCAM-1, the latter of which was confirmed by flow cytometry, consistent with angiogenic MSC-like pericytes. Furthermore, conditioned medium from each was shown to promote the proliferation of growth factor-starved lymphatic endothelial cells. Unlike kaposiform hemangioendothelioma-derived MSC-like pericytes and ADSCs, KLA isolates were defective in support of vascular network formation in co-cultures with either vascular or lymphatic endothelial cells. Genetic analysis by whole exome sequencing revealed novel variant alleles in 2 populations of KLA cells (BAD, TSC1) that may bear on aberrant pericyte growth and function.

Purpose: To report a novel intervention for the treatment of conjunctival lymphangiectasia-subconjunctival injection of bevacizumab., Methods: A 53-year-old white male presented with a 3-month history of right ocular discomfort and redness unresponsive to conventional topical treatment of lubricants and steroids. A clinical diagnosis of conjunctival lymphangiectasia was confirmed by biopsy. Bevacizumab (25 mg/mL) was injected subconjunctivally into the affected area., Results: An improvement in the degree of conjunctival chemosis was evident at 5 days postinjection. At 1-month follow-up, symptoms had fully resolved. No recurrence had been observed at 3 years' follow-up., Conclusions: Subconjunctival bevacizumab injection may be an effective treatment for conjunctival lymphangiectasia.

Rationale: Lymphatic vessels in the respiratory tract normally mature into a functional network during the neonatal period, but under some pathological conditions they can grow as enlarged, dilated sacs that result in the potentially lethal condition of pulmonary lymphangiectasia., Objective: We sought to determine whether overexpression of the lymphangiogenic growth factor (vascular endothelial growth factor-C [VEGF-C]) can promote lymphatic growth and maturation in the respiratory tract. Unexpectedly, perinatal overexpression of VEGF-C in the respiratory epithelium led to a condition resembling human pulmonary lymphangiectasia, a life-threatening disorder of the newborn characterized by respiratory distress and the presence of widely dilated lymphatics., Methods and Results: Administration of doxycycline to Clara cell secretory protein-reverse tetracycline-controlled transactivator/tetracycline operator-VEGF-C double-transgenic mice during a critical period from embryonic day 15.5 to postnatal day 14 was accompanied by respiratory distress, chylothorax, pulmonary lymphangiectasia, and high mortality. Enlarged sac-like lymphatics were abundant near major airways, pulmonary vessels, and visceral pleura. Side-by-side comparison revealed morphological features similar to pulmonary lymphangiectasia in humans. The condition was milder in mice given doxycycline after age postnatal day 14 and did not develop after postnatal day 35. Mechanistic studies revealed that VEGF recptor (VEGFR)-3 alone drove lymphatic growth in adult mice, but both VEGFR-2 and VEGFR-3 were required for the development of lymphangiectasia in neonates. VEGFR-2/VEGFR-3 heterodimers were more abundant in the dilated lymphatics, consistent with the involvement of both receptors. Despite the dependence of lymphangiectasia on VEGFR-2 and VEGFR-3, the condition was not reversed by blocking both receptors together or by withdrawing VEGF-C., Conclusions: The findings indicate that VEGF-C overexpression can induce pulmonary lymphangiectasia during a critical period in perinatal development.

Lymphatic vessels are thought to arise from PROX1-positive endothelial cells (ECs) in the cardinal vein in response to induction of SOX18 expression; however, the molecular event responsible for increased SOX18 expression has not been established. We generated mice with endothelial-specific, inducible expression of an RAF1 gene with a gain-of-function mutation (RAF1(S259A)) that is associated with Noonan syndrome. Expression of mutant RAF1(S259A) in ECs activated ERK and induced SOX18 and PROX1 expression, leading to increased commitment of venous ECs to the lymphatic fate. Excessive production of lymphatic ECs resulted in lymphangiectasia that was highly reminiscent of abnormal lymphatics seen in Noonan syndrome and similar "RASopathies." Inhibition of ERK signaling during development abrogated the lymphatic differentiation program and rescued the lymphatic phenotypes induced by expression of RAF1(S259A). These data suggest that ERK activation plays a key role in lymphatic EC fate specification and that excessive ERK activation is the basis of lymphatic abnormalities seen in Noonan syndrome and related diseases.

Diffuse pulmonary lymphatic diseases are typically diagnosed shortly after birth or in childhood, but rarely may become evident in adulthood. We report 3 adult patients who presented with diffuse interstitial lung disease clinically and radiologically but on biopsy were found to have diffuse pulmonary lymphatic disease (2 cases of pulmonary lymphangiectasis and 1 case of pulmonary lymphangiomatosis). These patients presented with the insidious onset of symptoms including shortness of breath and cough. Imaging studies of the chest showed diffuse pulmonary interstitial opacities, often with a perilymphatic distribution. The clinical differential diagnostic considerations before surgical lung biopsy included infection, neoplasm, and interstitial lung disease. The histopathologic features included abnormal vessels and associated fibrosis following lymphatic routes, namely visceral pleura, bronchovascular bundles, and interlobular septa. Lymphangiectasis was characterized by dilation of normally distributed lymphatic spaces, whereas lymphangiomatosis showed a complex anastamosing proliferation of lymphatic vascular spaces without significant dilatation. The dilated lymphatic spaces often had undergone muscularization, which could easily lead to misclassification as veins. Immunohistochemical staining for the lymphatic endothelial marker D2-40 was helpful in correctly classifying these lesions. Diffuse pulmonary lymphatic disease can rarely present in adulthood, wherein the histologic findings can be subtle and could be overlooked as nonspecific reactive changes or misdiagnosed as an idiopathic interstitial lung disease. Recognition of the characteristic lymphangitic distribution of abnormally dilated or reduplicated lymphatic spaces is key to the correct diagnosis.

Adrenomedullin (AM) and its receptor complexes, calcitonin receptor-like receptor (Calcrl) and receptor activity modifying protein 2/3, are highly expressed in lymphatic endothelial cells and are required for embryonic lymphatic development. To determine the role of Calcrl in adulthood, we used an inducible Cre-loxP system to temporally and ubiquitously delete Calcrl in adult mice. Following tamoxifen injection, Calcrl(fl/fl)/CAGGCre-ER™ mice rapidly developed corneal edema and inflammation that was preceded by and persistently associated with dilated corneoscleral lymphatics. Lacteals and submucosal lymphatic capillaries of the intestine were also dilated, while mesenteric collecting lymphatics failed to properly transport chyle after an acute Western Diet, culminating in chronic failure of Calcrl(fl/fl)/CAGGCre-ER™ mice to gain weight. Dermal lymphatic capillaries were also dilated and chronic edema challenge confirmed significant and prolonged dermal lymphatic insufficiency. In vivo and in vitro imaging of lymphatics with either genetic or pharmacologic inhibition of AM signaling revealed markedly disorganized lymphatic junctional proteins ZO-1 and VE-cadherin. The maintenance of AM signaling during adulthood is required for preserving normal lymphatic permeability and function. Collectively, these studies reveal a spectrum of lymphatic defects in adult Calcrl(fl/fl)/CAGGCre-ER™ mice that closely recapitulate the clinical symptoms of patients with corneal, intestinal and peripheral lymphangiectasia.

Objective: To determine the presence, degree, and extent of lymphatic, elastic, and collagen fiber alterations in dermatochalasis (DC) specimens., Design: Case control study of patients with DC compared with age-, gender-, and site-matched controls., Participants: A total of 25 eyelid specimens were studied; 15 of these were blepharoplasty specimens (experimental) and 10 were entropion/ectropion specimens of patients without DC (controls)., Methods: The number and maximal dilation of lymphangiectasia was measured by light microscopy, immunohistochemistry with lymphatic marker D2-40, and elastic tissue content by Verhoeff-van Gieson histochemistry. The number of macrophages was compared between patients with DC and controls in CD68 immunostained specimens., Main Outcome Measures: Lymphatic density, edema, and inflammation., Results: Dermatochalasis eyelid specimens showed increased lymphangiectasia density (5.6 vs. 2.4 lymphatics/high power field; P<0.05), maximal lymphatic dilation (127 vs. 51.5 μm; P<0.05), loss of elastic fibers (2.2 vs. 8.9 fibers/high power field; P<0.05), and greater disruption of collagen networks and edema compared with controls (increased stromal collagen bed of 752 vs. 269 μm; P<0.05; increased intercollagen space of 32.5 vs. 11.8 μm; P<0.05). Macrophages were present in greater quantities in DC specimens (28.6 vs. 11.9 macrophages/high power field; P<0.05)., Conclusions: Patients with DC show an increase in number and maximal dilation of lymphatic vessels in conjunction with widely spaced collagen bundles. This finding coexists with loss of elastic fibers, components known to be essential to the structure and function of the lymphatic system. Governed by macrophages, the pathogenesis of DC may begin with subclinical inflammation leading to elastolysis and secondary lymphostasis., Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article., (Copyright © 2011 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Diffuse pulmonary lymphangiomatosis (DPL) is a rare disease that is characterized by diffuse proliferation of abnormal pulmonary lymphatic channels. DPL occurs mostly in children and young adults and often undergoes a progressive clinical course, eventually causing deterioration of the lung. Both the clinical diagnosis and treatment of DPL remain a challenge. Here, we report a case of DPL in a 53-year-old Chinese woman with comprehensive investigations including pulmonary function tests, computer tomography (CT), bronchoscopy and histological examination of the lung biopsy, and review the literature.

We describe the histological examination of 18 aborted fetuses that had increased nuchal translucency (NT) between 11(+0) and 13(+6) weeks' gestation. The aim of this study was to assess the corresponding NT anatomic features by immunohistochemical (IHC) investigation. A morphological study was performed using lymphatic and blood endothelial specific markers, as well as smooth muscle actin (SMA). We found that all 18 cases were D2-40 positive, CD31 positive, and CD34 negative, suggesting the presence of nuchal lymph vessel ectasia. We found that 12/18 cases were SMA staining positive and 6/18 cases were SMA negative, suggesting that 6/18 cases had nuchal cystic lymphangiectasia, whereas 12/18 had cystic hygromas. The present data seem to confirm the reasonable hypothesis that lymphangiogenesis plays a relevant role in nuchal edema, increased NT, and that increased NT is the result of a lymphatic malformation or a delayed development of the lymphatic system.

Aims: To present the clinico-pathological findings of eight cases of acquired vulval lymphangiectasia (AVL) with discussion of the terminology and differential diagnosis., Methods: Vulvectomy or biopsy specimens from eight patients with AVL were reviewed. All patients had undergone surgery, lymphadenectomy and/or radiotherapy, most commonly for carcinoma of the cervix, up to 26 years prior to presentation with the lymphangiectatic lesions. Immunohistochemistry for CD31, CD34, D2-40, p53 and p16 was performed in each case., Results: The original clinical and pathological diagnoses were most frequently 'lymphangioma circumscriptum' but viral infection was considered in some cases. All specimens showed dermal lymphangiectasia associated with marked reactive epidermal hyperplasia. The lymphatic endothelial cells showed CD31 and D2-40 expression but CD34 was negative. The keratinocytes showed focal p53 immunoreactivity in four cases., Conclusions: AVL is the preferred nomenclature for the lesions presented herein. The clinical and histological features usually are characteristic but the differential diagnosis may include condyloma and differentiated type vulval intraepithelial neoplasia (VIN). Immunohistochemistry may be helpful but lack of CD34 expression should be noted and may prove useful in the differential diagnosis of other vulval vascular lesions. Focal p53 protein immunoreactivity should not be considered indicative of differentiated type VIN in this clinical setting.

This case report presents a hydroptic trisomy 21 fetus affected by lymphatic dysplasia with no other malformations. Our studies using CD31, CD34, smooth muscle actin, desmin, and D2-40 antibodies immunohistochemistry confirm the diagnosis of severe pulmonary lymphangiectasia associated with lymphangiectasia ih the mediastinum and small bowel.

Lymphangioma (LA) and congenital pulmonary lymphangiectasis (CPL) are part of a spectrum of lymphatic disorders less well characterized than other vascular tumors and malformations. Recent studies showed proliferative and involutional growth phases for hemangiomas that distinguish them from malformations. We investigated immunohistochemical reactivity and proliferative activity to determine whether a similar diagnostically/prognostically useful pattern exists for LA, comparing LA with CPL as a malformative lesion. Immunohistochemical tests for vimentin, Factor VIII-related protein, CD31, CD34, CD45RO, smooth muscle actin, Type IV collagen, MIB-1, bcl-2, and topoisomerase IIalpha were performed on 20 LAs and 10 cases of CPL. Giemsa staining was also performed to quantitate mast cells. Clinicopathologic correlation was performed by medical record review. LA and CPL shared a similar immunohistochemical profile for vimentin, Factor VIII-related protein, CD31, CD34, smooth muscle actin, CD34, and, to a lesser extent, CD45RO. CD31 and CD34 displayed the most uniform pattern of endothelial reactivity, although CD34 had high background staining. bcl-2 was negative. Four LAs exhibited focal low reactivity for MIB-1 and topoisomerase IIalpha; recent infection and thrombosis were associated conditions. LAs displayed seven-fold more mast cells and more reactive T lymphocytes than did cases of CPL. LA and CPL had similar immunohistochemical profiles; LA resembled vascular malformations more than hemangiomas. CD31 and CD34 were useful for detection of small lymphatics at resection margins of LA, a feature associated with recurrence. MIB-1 and topoisomerase IIalpha expression were associated with inflammatory, thrombotic, or reactive processes and were not diagnostically useful. Abundant mast cells, which also were noted in other soft tissue neoplasms, prompt speculation concerning their role in the growth of LAs.

Immunohistochemical staining was used to demonstrate basement membrane (BM) laminin and type IV collagen in eight cases of Kaposi's sarcoma (KS). These KS were not associated with AIDS and represented different histological stages of the disease: patch (three cases), plaque (one case), and nodule (four cases). Nine cases of benign angiogenic lesions, five of blood vessel origin, and four of lymphatic vessel origin were also studied. An early event in vascular proliferation at the patch stage of KS was an intersection of dermal collagen bundles and the appearance of granular BM material around this space. With the increase of amount and linear arrangement of BM material, well-defined capillaries were formed. Two types of capillary were found in KS lesions. One showed morphological features of blood capillaries, with a round lumen; thick, continuous BM, and occasional pericytes in the wall. The other included irregularly shaped vessels with thin, often disrupted BMs; thus these capillaries morphologically resembled lymphatic capillaries. BM staining also clearly revealed the vascular nature of the nodular lesions of KS, which were composed of a network of slit-like spaces surrounded by BMs. The solid tumor cell areas were sparse; they were composed of spindle-shaped cells surrounded by thin, interrupted basal laminae. By using antibodies against human laminin and human type IV collagen, it was also possible to demonstrate thin, widely disrupted BMs subendothelially in normal dermal lymphatic capillaries. Typically, the BMs in lymphangiomas and lymphangiectasias were continuous and more clearly defined.

Ceruloplasmin labeled with (67)copper and administered intravenously to dogs, control human subjects, and patients with excessive gastrointestinal loss was shown to fulfill the requirements for a label for quantification of gastrointestinal protein loss. The radiocopper moiety was poorly absorbed from the gastrointestinal tract, not actively secreted into the intestinal tract, and did not alter significantly the metabolism of ceruloplasmin. Approximately 70% of the body pool of ceruloplasmin in both dog and man was within the intravascular space. In control human subjects the mean ceruloplasmin concentration was 30 mg per 100 ml with total circulating and total body ceruloplasmin pools of 15.5 and 22 mg per kg, respectively. In patients with excessive gastrointestinal protein loss secondary to intestinal lymphangiectasia, the serum ceruloplasmin concentration was reduced to 16 mg per 100 ml with a comparable reduction in the total circulating and total body ceruloplasmin pools to 8.8 and 12 mg per kg. The survival half-time of ceruloplasmin was 6.1 days in normal human subjects and 4.5 days in normal dogs. From 1.0 to 1.9% of the intravascular pool of ceruloplasmin was lost into the gastrointestinal tract of the dog per day, representing less than 11% of the over-all metabolism of this protein. In control human subjects from 1.9 to 3.9% of the intravascular pool was lost into the gastrointestinal tract each day, representing a maximum of from 11 to 22% of the over-all metabolism of this molecule. In contrast, patients with intestinal lymphangiectasia had a markedly shortened ceruloplasmin survival of 3.1 days, with from 15 to 40% of the intravascular pool of ceruloplasmin cleared into the gastrointestinal tract daily. This represented 76% of the over-all metabolism of this protein. Thus, although bulk loss of serum proteins into the gastrointestinal tract does not normally appear to be a significant factor in protein metabolism in normal dogs and men, such loss is a major factor in the pathogenesis of the hypoceruloplasminemia noted in patients with intestinal lymphangiectasia.