Vascular endothelial growth factor receptor 3 (VEGFR3) and LYVE-1 are specifically expressed in the endothelium of the lymphatic systems. VEGF-C, D, FOXC2, Prox 1, and SOX18 are known to play central roles in lymphatic development. We investigated the expression of regulatory molecules for lymphangiogenesis in the duodenal mucosa of idiopathic intestinal lymphangiectasia.
Biopsy samples were obtained from duodenal biopsies in patients with intestinal lymphangiectasia complicated with protein-losing from white spot lesions in which lymphangiectasia was histologically confirmed. Immunohistochemical analysis for VEGFR3 and LYVE-1 was performed. mRNA expression of VEGF-C, VEGF-D, VEGFR3, and transcription factors was determined by the quantitative reverse transcription-polymerase chain reaction method.
In the control mucosa, VEGFR3 was weakly expressed on the central lymphatic vessels in the lamina propria and LYVE-1 was expressed mainly on the lymphatic vessels in the submucosa. In intestinal lymphangiectasia, VEGFR3 and LYVE-1 expression levels were increased on the mucosal surface corresponding to widely dilated lymphatic vessels, while they were decreased in the deeper mucosa. mRNA expression study showed a significant increase in the expression level of VEGFR3 in lymphangiectasia, but the expression of VEGF-C and -D mRNA was significantly suppressed compared with that in controls despite the presence of lymphangiectasia. The mRNA expression levels of FOXC2 and SOX18 were also decreased, whereas Prox 1 was not altered.
There is an altered expression of regulatory molecules for lymphangiogenesis in the duodenal mucosa in these patients.
"It is congenital or idiopathic, and has been linked to several syndromes including Milroy's, Von Recklinghausen, Turner, Klippel Trenaunay, Hennekam, and Noonan's (Keberle et al. 2000; Suresh et al. 2009). An immunohistochemical study by Hokari et al. (2008) identified several growth factors and receptors significant in lymphangiogenesis and lymphangiectasia, namely VEGF-C and -D, FOXC2, SOX18, Prox 1, and VEGFR3 and LYVE-1, respectively, the latter two of which were specific and sensitive markers for lymphatics. Macdonald et al. (2010) recently found an association between PIL and severity of small intestinal angiodysplasia. "
[Show abstract][Hide abstract] ABSTRACT: To investigate the toxicity and carcinogenic potential of indole-3-carbinol (I3C), the National Toxicology Program has conducted 13-week subchronic studies in Fisher 344 rats and B6C3F1 mice, and chronic 2-year bioassays in Sprague-Dawley rats and B6C3F1 mice. While the chronic study results are not yet available, subchronic study results and short-term special evaluations of interim sacrifices in the 2-year rat bioassay are presented. F344 rats were orally gavaged ≤300 mg I3C/kg body weight 5 days a week for 13 weeks. Rats treated with ≥150 mg/kg demonstrated a dose-related dilation of lymphatics (lymphangiectasis) of the duodenum, jejunum, and mesenteric lymph nodes. Material within dilated lacteals stained positively for Oil Red O and Sudan Black, consistent with lipid. Electron microscopic evaluation confirmed extracellular lipid accumulation within the villar lamina propria, lacteals, and within villar macrophages. Analyses of hepatic and pulmonary CYP1A enzymes demonstrated dose-dependent I3C induction of CYP1A1 and 1A2. B6C3F1 mice orally gavaged ≤250 mg I3C/kg body weight did not demonstrate histopathological changes; however, hepatic CYP induction was similar to that in rats. The histopathologic changes of intestinal lymphangiectasis and lipidosis in this study share similarities with intestinal lymphangiectasia as observed in humans and dogs. However, the resultant clinical spectrum of protein-losing enteropathy was not present.
"sia is characterized by highly dilated lymphatic capil - laries in the intestinal villi . Because the normal lymphatic response to changes in interstitial pressure is hindered by this hyperdilation , absorption by the intestine is compro - mised . Moreover , the levels of FOXC2 and SOX18 tran - scription are significantly lower in these patients ( Hokari et al . 2008 ; Johnson and Oliver 2009 ) ."
[Show abstract][Hide abstract] ABSTRACT: The lymphatic vascular system is essential for lipid absorption, fluid homeostasis, and immune surveillance. Until recently, lymphatic vessel dysfunction had been associated with symptomatic pathologic conditions such as lymphedema. Work in the last few years had led to a better understanding of the functional roles of this vascular system in health and disease. Furthermore, recent work has also unraveled additional functional roles of the lymphatic vasculature in fat metabolism, obesity, inflammation, and the regulation of salt storage in hypertension. In this review, we summarize the functional roles of the lymphatic vasculature in health and disease.
Genes & development 10/2010; 24(19):2115-26. DOI:10.1101/gad.1955910 · 10.80 Impact Factor
"Several genes, such as VEGFR3 (vascular endothelial growth factor receptor 3), prospero-related homeobox-transcriptional factor PROX1, forkhead transcriptional factor FOXC2 and SOX18 are implicated in the development of the lymphatic system. In a recent paper, Hokari et al. reported inconsistently changed expressions of regulatory molecules for lymphangiogenesis in the duodenal mucosa of PIL patients . "
[Show abstract][Hide abstract] ABSTRACT: Primary intestinal lymphangiectasia (PIL) is a rare disorder characterized by dilated intestinal lacteals resulting in lymph leakage into the small bowel lumen and responsible for protein-losing enteropathy leading to lymphopenia, hypoalbuminemia and hypogammaglobulinemia. PIL is generally diagnosed before 3 years of age but may be diagnosed in older patients. Prevalence is unknown. The main symptom is predominantly bilateral lower limb edema. Edema may be moderate to severe with anasarca and includes pleural effusion, pericarditis or chylous ascites. Fatigue, abdominal pain, weight loss, inability to gain weight, moderate diarrhea or fat-soluble vitamin deficiencies due to malabsorption may also be present. In some patients, limb lymphedema is associated with PIL and is difficult to distinguish lymphedema from edema. Exsudative enteropathy is confirmed by the elevated 24-h stool alpha1-antitrypsin clearance. Etiology remains unknown. Very rare familial cases of PIL have been reported. Diagnosis is confirmed by endoscopic observation of intestinal lymphangiectasia with the corresponding histology of intestinal biopsy specimens. Videocapsule endoscopy may be useful when endoscopic findings are not contributive. Differential diagnosis includes constrictive pericarditis, intestinal lymphoma, Whipple's disease, Crohn's disease, intestinal tuberculosis, sarcoidosis or systemic sclerosis. Several B-cell lymphomas confined to the gastrointestinal tract (stomach, jejunum, midgut, ileum) or with extra-intestinal localizations were reported in PIL patients. A low-fat diet associated with medium-chain triglyceride supplementation is the cornerstone of PIL medical management. The absence of fat in the diet prevents chyle engorgement of the intestinal lymphatic vessels thereby preventing their rupture with its ensuing lymph loss. Medium-chain triglycerides are absorbed directly into the portal venous circulation and avoid lacteal overloading. Other inconsistently effective treatments have been proposed for PIL patients, such as antiplasmin, octreotide or corticosteroids. Surgical small-bowel resection is useful in the rare cases with segmental and localized intestinal lymphangiectasia. The need for dietary control appears to be permanent, because clinical and biochemical findings reappear after low-fat diet withdrawal. PIL outcome may be severe even life-threatening when malignant complications or serous effusion(s) occur.
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