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Lymphatic Endothelium (lymphatic + endothelium)
Selected AbstractsAbsence of lymphatic vessels in human dental pulp: a morphological studyEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2010Renato Gerli Gerli R, Secciani I, Sozio F, Rossi A, Weber E, Lorenzini G. Absence of lymphatic vessels in human dental pulp: a morphological study. Eur J Oral Sci 2010; 118: 110,117. © 2010 The Authors. Journal compilation © 2010 Eur J Oral Sci Few and controversial data are available in the literature regarding the presence of lymphatic vessels in the human dental pulp. The present study was designed to examine morphologically the existence of a lymph drainage system in human dental pulp. Human dental pulp and skin sections were immunohistochemically stained with specific antibodies for lymphatic endothelium (D2-40, LYVE-1, VEGFR-3 [vascular endothelial growth factor receptor-3], and Prox-1), with the pan-endothelial markers CD31 and von Willebrand factor (vWF), and with the blood-specific marker CD34. Several blood vessels were identified in human pulps and skin. Lymphatic vessels were found in all human skin samples but in none of the pulps examined. Western blotting performed on human dermis and on pulps treated with collagenase (to remove odontoblasts) confirmed these results. Transmission electron microscopy indicated that vessels which, by light microscopy, appeared to be initial lymphatic vessels had no anchoring filaments or discontinuous basement membrane, both of which are typical ultrastructural characteristics of lymphatic vessels. These results suggest that under normal conditions human dental pulp does not contain true lymphatic vessels. The various theories about dental pulp interstitial fluid circulation should be revised accordingly. [source] Role of intratumoral lymphatic vessels in the lymph node dissemination of laryngopharyngeal squamous cell carcinomaHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 6 2010Adolfo Hinojar-Gutiérrez MD Abstract Background The development of new markers for lymphatic endothelium allowed the study of intratumoral lymphatic microcirculation, as well as its association with lymph node metastasis. Methods In all, 120 patients with laryngopharyngeal squamous cell carcinoma (LPSCC) without previous treatment were retrospectively studied. The immunohistochemical determination of PA2.26 antigen/podoplanin was used to assess intratumoral lymphatic vessels (ILVs) in the primary tumor. Results Multivariate analysis revealed that lymph node metastasis was associated with tumor location (p = .001), differentiation grade (p = .02), and ILV (p = .013). Hypopharyngeal and supraglottic locations, poor grade of differentiation, and ILV, respectively, increased the risk of developing lymph node metastasis 13.5-, 4.7-, 5.2-, and 3.2-fold. Conclusions In our series, the presence of ILV in the primary tumor was an independent risk factor for the development of lymph node metastasis. The incorporation of ILV assessment into routine clinicopathological study might improve the evaluation of patients with LPSCC. © 2009 Wiley Periodicals, Inc. Head Neck, 2010 [source] Structure, lymphatic vascularization and lymphocyte migration in mucosa-associated lymphoid tissueIMMUNOLOGICAL REVIEWS, Issue 1 2003Giacomo Azzali Summary:, In this review, we consider the morphological aspects and topographical arrangement of gut-associated lymphoid tissue (GALT) (solitary and aggregate lymph nodules or Peyer's patches) and of vermiform appendix in the human child and in some mammals. The spatial arrangement of the vessels belonging to apparatus lymphaticus periphericus absorbens (ALPA) and of blood vessels within each lymphoid follicle as well as the ultrastructural characteristics of the lymphatic endothelium with high absorption capacity are considered. Particular attention is also paid to the morphological and biomolecular mechanisms inducing lymphocyte transendothelial migration to the bloodstream by means of lymphatic vessels as well as their passage from blood into lymphoid tissue through the high endothelial venules (HEVs). The preferential transendothelial passage of lymphocytes and polymorphonuclear neutrophils within ALPA vessels of the interfollicular area does not occur following the opening of intercellular contacts, but rather it occurs by means of ,intraendothelial channels'. In HEVs, on the contrary, the hypothesis is plausible that lymphocyte transendothelial migration into lymphoid tissue occurs through a channel-shaped endothelial invagination entirely independent of interendothelial contacts. The lymph of ALPA vessels of the single Peyer's patch is conveyed into precollector lymphatic vessels and into prelymph nodal collectors, totally independent of the ALPA vessels of the gut segments devoid of lymphoid tissue. The quantitative distribution of T lymphocytes in the lymph of mucosal ALPA vessels suggests a prevalent function of fluid uptake, whereas a reservoir and supply function is implicated for the vessels of interfollicular area. The precollector lymphatic vessels and prelymph nodal collectors are considered to be vessels with low absorption capacity, whose main function is lymph conduction and flow. [source] Effects of lithium carbonate on rat seminiferous tubules: an ultrastructural studyINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 6 2006O. Zarnescu Summary Lithium salts are commonly used for treatment of bipolar disorder but prolonged treatment with therapeutic doses induces substantial toxic effects. In the present study we examined the effects of lithium carbonate on the ultrastructure of rat seminiferous tubules. Rats were exposed to lithium carbonate at doses of 35 mg/kg/day for 21 days. After lithium treatment, the tunica propria widened and folded together with convolutions of the basement membrane, myoid cells and lymphatic endothelium. In the seminiferous epithelium loss of germ cell attachment and appearance of expanded intercellular spaces between spermatogenic cells were observed. Early stages of spermatogenic cells showed nuclear protrusions or swellings because of an extensive enlargement of the outer nuclear membrane. Round spermatids exhibited abnormally shaped acrosomes and dilation of the subacrosomal space. Many abnormal, degenerated late spermatids with random orientation were seen towards the basal and adluminal compartments of the seminiferous epithelium. In addition, spermatids exhibited alteration in F-actin bundle ectoplasmic specialization and contained many mitochondria-associated granular bodies. [source] The expression of E-selectin and chemokines in the cultured human lymphatic endothelium with lipopolysaccharidesJOURNAL OF ANATOMY, Issue 5 2008Yoshihiko Sawa Abstract This study investigated the expression of selectins and chemokines in cultured human lymphatic endothelial cells stimulated with lipopolysaccharides. In microarray, vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 gene expressions in the lymphatic endothelium with lipopolysaccharides did not change at 0.5 h but increased two- to three-fold at 12 h, whereas E-selectin increased 10-fold at 0.5 h and 68-fold at 12 h compared with untreated cells. The E-selectin mRNA and protein increased in the lymphatic endothelial cells with lipopolysaccharides at more than two-fold levels compared with human umbilical vein endothelial cells. Induction of Cys-Cys chemokine ligand 2, 3, 5, 7, 8 and 20 mRNAs in the lymphatic endothelial cells with lipopolysaccharides was detected in microarray and real-time PCR. The Cys-Cys chemokine ligand 2, 5 and 20 mRNA amounts in cells with high concentration lipopolysaccharides were larger in the lymphatic endothelial cells than in human umbilical vein endothelial cells. The Cys-Cys chemokine ligand 3 and 8 mRNAs were not detected in human umbilical vein endothelial cells. Induction of Cys-X-Cys chemokine ligand 1, 3, 5, 6 and 8 mRNAs was detected in the lymphatic endothelial cells with lipopolysaccharides. The Cys-X-Cys chemokine ligand 3, 5 and 8 mRNA amounts in cells with high concentration lipopolysaccharides were larger in the lymphatic endothelial cells than in human umbilical vein endothelial cells. In conclusion, it was demonstrated that the cultured human lymphatic endothelial cells express E-selectin and phagocyte-attractive chemokine genes. [source] Markers for the lymphatic endothelium: In search of the holy grail?MICROSCOPY RESEARCH AND TECHNIQUE, Issue 2 2001Jonathan P. Sleeman Abstract The ability to discriminate reliably at the histological level between blood and lymphatic microcapillaries would greatly assist the study of a number of biological and pathological questions and may also be of clinical utility. A structure,function comparison of these types of microcapillary suggests that differences which could function as markers to allow discrimination between blood and lymphatic endothelium should exist. Indeed, to date a variety of such markers have been proposed, including basement membrane components, constituents of junctional complexes such as desmoplakin and enzymes such as 5,-nucleotidase. Additionally, a variety of cell surface molecules are thought to be differentially expressed, including PAL-E, VEGFR-3, podoplanin, and LYVE-1. Several of the lymphatic markers proposed in the literature require further characterization to demonstrate fully their lymphatic specificity and some have proven not to be reliable. The relative merits and drawbacks of each of the proposed markers is discussed. Microsc. Res. Tech. 55:61,69, 2001. © 2001 Wiley-Liss, Inc. [source] Development of the avian lymphatic system,MICROSCOPY RESEARCH AND TECHNIQUE, Issue 2 2001Jörg Wilting Abstract Recently, highly specific markers of the lymphatic endothelium have been found enabling us to reinvestigate the embryonic origin of the lymphatics. Here we present a review of our studies on the development of the lymphatic system in chick and quail embryos. We show that the lymphatic endothelium is derived from two sources: the embryonic lymph sacs and mesenchymal lymphangioblasts. Proliferation studies reveal a BrdU-labeling index of 11.5% of lymph sac endothelial cells by day 6.25, which drops to 3.5% by day 7. Lymphangioblasts are able to integrate into the lining of lymph sacs. Lymphatic endothelial cells express the vascular endothelial growth factor (VEGF) receptors-2 and -3. Their ligand, VEGF-C, is expressed almost ubiquitously in embryonic and fetal tissues. Elevated expression levels are found in the tunica media of large blood vessels, which usually serve as major routes for growing lymphatics. The homeobox gene, Prox1, is expressed in lymphatic but not in blood vascular endothelial cells throughout all stages examined, namely, in developing lymph sacs of day 6 embryos and in lymphatics at day 16. Experimental studies show the existence of lymphangioblasts in the mesoderm, a considerable time before the development of the lymph sacs. Lymphangioblasts migrate from the somites into the somatopleure and contribute to the lymphatics of the limbs. Our studies indicate that these lymphangioblasts already express Prox1. Microsc. Res. Tech. 55:81,91, 2001. © 2001 Wiley-Liss, Inc. [source] Lymphatic vessel density in pulmonary adenocarcinoma immunohistochemically evaluated with anti-podoplanin or anti-D2-40 antibody is correlated with lymphatic invasion or lymph node metastasesPATHOLOGY INTERNATIONAL, Issue 4 2007Yoshin Adachi In lung cancers, lymph node metastasis of cancer cells is one of the most important prognostic factors, and lymphatic vessel invasion (LVI) is very important in the stage preceding lymph node metastases. Recently, it has been reported that lymphatic vessel density (LVD) is associated with lymph node metastasis. The aim of the present study was to evaluate the relationship between LVD and LVI based on the immunohistochemical expression of podoplanin or D2-40, which are new specific markers for lymphatic endothelium. Using 76 cases of pulmonary adenocarcinoma, the relationship between LVD and LVI, lymph node metastases, vascular endothelial growth factor C (VEGF-C), VEGF-D or hepatocyte growth factor (HGF) expression was investigated. LVD was significantly associated with LVI, lymph node metastases and VEGF-D expression. LVI was also associated with lymph node metastases, histological subtype, VEGF-C or VEGF-D expression. High LVD, induced by VEGF-C or VEGF-D expression of cancer cells, is a good indicator of lymphatic metastases and LVI in pulmonary adenocarcinoma. [source] Prediction of lymphatic invasion by peritumoral lymphatic vessel density in prostate biopsy coresTHE PROSTATE, Issue 10 2008Kenji Kuroda Abstract BACKGROUND Lymphatic invasion in radical prostatectomy specimens has been suggested to be an unfavorable prognostic factor in clinically localized prostate cancer. Lymphangiogenesis detected by antibodies specific for lymphatic endothelial cells has been associated with lymphatic invasion and lymph node metastasis in prostate cancer. This study was designed to examine whether lymphangiogenesis in prostate biopsy could predict lymphatic spread in radical prostatectomy specimens. METHODS Paraffin-embedded positive biopsy cores obtained from 99 patients who underwent radical prostatectomy at our institution were immunostained with D2-40 monoclonal antibody, which specifically recognizes lymphatic endothelium. The association between lymphatic parameters in prostate biopsy and pathological parameters in radical prostatectomy specimens was analyzed. RESULTS Peritumoral and intratumoral lymphatic (ITL) vessels were observed in 90 (90.9%) and 23 cases (23.2%). Average and maximal peritumoral lymphatic vessel density (PTLD) and the presence of ITL in positive biopsy cores were significantly associated with positive biopsy core rates (P,=,0.0015 for average PTLD, P,<,0.0001 for maximal PTLD, and P,=,0.0038 for ITL) and lymphatic vessel invasion (P,<,0.0001 for average PTLD, P,<,0.0001 for maximal PTLD, and P,=,0.0322 for ITL). Among preoperative parameters, the biopsy Gleason score (P,=,0.0092, HR,=,6.108) and average PTLD (P,=,0.0034, HR,=,1.860) were significant predictors of lymphatic invasion in radical prostatectomy specimens in multivariate analysis. CONCLUSIONS PTLD in prostate biopsy specimens assessed by immunohistochemistry using D2-40 antibody could be a useful parameter for predicting lymphatic spread of clinically localized prostate cancer. Prostate 68:1057,1063, 2008. © 2008 Wiley-Liss, Inc. [source] From tumor lymphangiogenesis to lymphvascular nicheCANCER SCIENCE, Issue 6 2009Satoshi Hirakawa Metastasis in sentinel lymph nodes indicates the initial spread of tumors from a primary site. The recent discovery of tumor-associated growth of lymphatic vessels clarified that tumor lymphangiogenesis actively promotes enhanced draining/sentinel lymph node metastasis. Studies of experimental carcinogenesis have further established that tumors continue to induce lymphangiogenesis in metastatic foci such as draining lymph nodes. Lymphangiogenesis within draining lymph nodes probably contributes to enhanced distant lymph node and distant organ metastases. Lymph node lymphangiogenesis has recently been identified in several human malignancies, such as cutaneous malignant melanoma. Tumor-associated lymphangiogenesis thus has potential significance not only at the primary site, but also in lymph nodes. Primary tumors induce new lymphatic vessel growth in draining lymph nodes before metastasis. The remarkable enlargement of sinusoidal lymphatic endothelium might facilitate tumor cell transport to the lymph nodes, and potentially contribute to the migration, residence, and/or survival of metastatic tumor cancer stem cells by inducing a specific tumor microenvironment. Therefore, the novel concept of ,lymphvascular niche' is proposed herein to explain lymphatic network expansion. This concept might help to improve understanding of the molecular mechanism of lymph node metastasis, and change therapeutic approaches to treating cancer metastasis. (Cancer Sci 2009; 100: 983,989) [source] | ||||||||||