Distribution Of Lymphatic Vessels Research Articles

Lymphatic Mapping with Multi-Lymphosome Indocyanine Green Lymphography in Legs with Lymphedema

AbstractIt is observed that the locations of the most functional lymphatic vessels in the lymphedematous limbs can differ significantly from those in healthy limbs. The aim of this study was to elucidate the lymphatic map of lymphedematous limbs. We retrospectively analyzed 59 patients (118 limbs) with lower limb lymphedema. Fifty-five were women and four were men. The mean age and duration of lymphedema was 62.4 and 7.7 years, respectively. For the lateral thigh lymphosome, we injected indocyanine green (ICG) at the lateral knee and measured the distance (Dt) between the anterior superior iliac spine (ASIS) and the point where the lymphatic vessels crossed the reference line (the line connecting the ASIS and the patellar center). For the lateral calf lymphosome, we injected ICG at the lateral ankle and measured the distance (Dc) between the inferior patellar border and the point where the lymphatic vessels crossed the reference line (the anterior border of the tibia). In the lateral thigh, the mean Dt was 30.4 ± 0.6 cm (range, 0–41 cm) and the distribution peaked at approximately 30 cm from the ASIS. In the calf, the mean Dc was 13.1 ± 0.9 cm (range, −11 to 32 cm). The distribution of lymphatic vessel locations was highly variable. We could establish the lymphatic map in the lymphedematous legs. The distribution of lymphatic vessels in the thigh and lower legs had one and two peaks, respectively.

Magnetic resonance lymphography findings across different clinical stages of lower limb lymphedema

ObjectiveTo investigate the imaging findings of lower limb lymphedema using magnetic resonance lymphography (MRL). MethodsMRL was used to record the lymphatic vessel morphology, distribution of lymphatic vessels, dermal backflow (DBF), and morphology of inguinal lymph nodes in 112 patients (175 affected limbs) with the lower limb lymphedema at different clinical stages (according to the International Society of Lymphology staging criteria 2020). ResultsThe lymphatic vessel morphology significantly differed in different clinical stages (X2=59.306; P=0.000). ISL stage I is dominated by ‘scattered beads’ and ‘branch-like’ distribution, ISL stage Ⅱ has tree branch or ‘capillary-like’ distribution, and ISL stage Ⅲ primarily has a capillary pattern and contrast agent accumulation in the foot. There were statistically significant differences in the distribution of lymphatic vessels and DBF in different clinical stages. The distribution of enhanced lymphatic vessels was distal to the knee in ISL stage I, involved areas below the knee joint or involving the whole limb in ISL stage II, and Involving the whole limb in ISL stage III (X2=44.591; P=0.000). With the progression of edema, DFB severity increased (X2=76.416; P=0.000). ConclusionMRL revealed the morphology and distribution of lymphatic vessels and detected abnormal inguinal lymph nodes in patients at different stages of lymphedema, which can provide reference information for surgical treatment.

Periarterial or perivenous invasion is an independent indicator of lymph node metastasis in invasive breast carcinoma of no special type

Pathological diagnosis of breast cancer often includes cases of lymph node metastases without lymphatic or lymphovascular invasion by the primary tumor. In this study, to resolve this discrepancy, we designed a sensitive method to detect lymphatic invasion and correlate it with lymph node metastasis. Elastica van Gieson (EVG) staining and D2–40 immunohistochemistry revealed the abundant distribution of lymphatic vessels around blood vessels in the mammary tissue in close proximity to the elastic fibers around the arteries and veins. Based on the histological location of the blood and lymphatic vessels, we hypothesized that, in breast cancer, perivascular invasion is similar to lymphatic invasion and correlates with the presence of lymph node metastasis. Using EVG staining, perivascular invasion was histologically classified into periarterial invasion (periA), perivenous invasion (periV), and periarterial or perivenous invasion (periA/V). We tested our method and compared it to other methods commonly used for identifying lymphatic invasion in 105 patients with invasive breast carcinoma of no special type (IBC-NST) who received minimal preoperative therapy. The correlation between perivascular invasion and lymph node metastasis in these patients was statistically analyzed, including findings related to lymphatic invasion, such as retractile artifacts and perineural invasion. PeriA, periV, and periA/V showed significant correlations with lymph node metastasis. PeriA/V had high sensitivity and negative predictive value. The odds ratio (OR) for periV was significantly high in the univariate analysis, while the ORs for periA/V, retraction artifacts, and perineural invasion were significantly high in both the univariate and multivariate analyses. In particular, periA/V revealed a strong correlation with lymph node metastasis (OR: 61.8). These findings indicate that the IBC-NST periA/V ratio is a sensitive pointer of lymphatic invasion and could be an independent and reliable indicator of lymph node metastasis.

Widespread distribution of lymphatic vessels in human dura mater remote from sinus veins.

Background and purpose: Previous experimental studies have shown that meningeal lymphatic vessels are located primarily along the walls of the dural sinus veins. Whether they are more widespread throughout human dura mater has presently not been characterized. The present study explored in humans whether meningeal lymphatic vessels may be identified remote from the sinus veins and whether they differ in the various location of dura mater. Methods: We included 15 patients who underwent neurosurgery, in whom dura mater was removed as part of the planned procedure. Tissue was prepared for immunohistochemistry using the lymphatic endothelial cell markers lymphatic vessel endothelial hyaluronan receptor 1 protein (LYVE-1), podoplanin and vascular endothelial growth factor receptor 3 (VEGFR3). Results: Lymphatic endothelial cell positive cells were found in dura mater at the posterior fossa (n = 8), temporal skull base (n = 5), frontal convexity (n = 1), and cranio-cervical junction (n = 1). They were most commonly seen remote from blood vessels, but also occurred along blood vessels, and seemed to be most abundant at the skull base. Conclusion: The present observations show that human lymphatic vessels are widespread in dura mater, not solely lining the dural sinuses.

Microanatomical organization of hepatic venous lymphatic system in humans.

Lymphatic fluid drains from the liver via the periportal lymphatic, hepatic venous lymphatic, and superficial lymphatic systems. We performed a postmortem study to clarify the three-dimensional structure and flow dynamics of the human hepatic venous lymphatic system, as it still remains unclear. Livers were excised whole from three human cadavers, injected with India ink, and sliced into 1-cm sections from which veins were harvested. The distribution of lymphatic vessels was observed in 5 μm sections immunostained for lymphatic and vascular markers (podoplanin and CD31, respectively) using light microscopy. Continuity and density of lymphatic vessel distribution were assessed in en-face whole-mount preparations of veins using stereomicroscopy. The structure of the external hepatic vein wall was assessed with scanning electron microscopy (SEM). The lymphatic dynamics study suggested that lymphatic fluid flows through an extravascular pathway around the central and sublobular veins. A lymphatic vessel network originates in the wall of sublobular veins, with a diameter greater than 110 μm, and the peripheral portions of hepatic veins and continues to the inferior vena cava. The density distribution of lymphatic vessels is smallest in the peripheral portion of the hepatic vein (0.03%) and increases to the proximal portion (0.22%, p = 0.012) and the main trunk (1.01%, p < 0.001), correlating positively with increasing hepatic vein diameter (Rs = 0.67, p < 0.001). We revealed the three-dimensional structure of the human hepatic venous lymphatic system. The results could improve the understanding of lymphatic physiology and liver pathology.

Endothelial Microparticle-Mediated Transfer of microRNA-19b Inhibits the Function and Distribution of Lymphatic Vessels in Atherosclerotic Mice

In recent years, the function of the lymphatic system in atherosclerosis has attracted attention due to its role in immune cell trafficking, cholesterol removal from the periphery, and regulation of the inflammatory response. However, knowledge of the mechanisms regulating lymphangiogenesis and lymphatic function in the pathogenesis of atherosclerosis is limited. Endothelial microparticles carrying circulating microRNA (miRNA)s are known to mediate cell–cell communication, and our previous research showed that miRNA-19b in EMPs (EMPmiR-19b) was significantly increased in circulation and atherosclerotic vessels, and this increase in EMPmiR-19b promoted atherosclerosis. The present study investigated whether atherogenic EMPmiR-19b influences pathological changes of the lymphatic system in atherosclerosis. We first verified increased miR-19b levels and loss of lymphatic system function in atherosclerotic mice. Atherogenic western diet-fed ApoE-/- mice were injected with phosphate-buffered saline, EMPs carrying control miRNA (EMPcontrol), or EMPmiR-19b intravenously. The function and distribution of the lymphatic system was assessed via confocal microscopy, Evans blue staining, and pathological analysis. The results showed that lymphatic system dysfunction existed in the early stage of atherosclerosis, and the observed pathological changes persisted at the later stage, companied by an increased microRNA-19b level. In ApoE-/- mice systemically treated with EMPmiR-19b, the distribution, transport function, and permeability of the lymphatic system were significantly inhibited. In vitro experiments showed that miRNA-19b may damage the lymphatic system by inhibiting lymphatic endothelial cell migration and tube formation, and a possible mechanism is the inhibition of transforming growth factor beta receptor type II (TGF-βRII) expression in lymphatic endothelial cells by miRNA-19b. Together, our findings demonstrate that atherogenic EMPmiR-19b may destroy lymphatic system function in atherosclerotic mice by downregulating TGF-βRII expression.

Diagnostic significance of CyclinD1 and D2-40 expression for follicular neoplasm of the thyroid

ObjectivesTo evaluate the expression and differential diagnostic significance of CyclinD1 and D2–40 in follicular neoplasm (FN) and other thyroid adenomatoid lesions. MethodsA total of 144 cases of thyroid adenomatoid lesions were enrolled. Immunohistochemistry for CyclinD1 and D2–40 was performed. ResultsWe found two patterns of CyclinD1 expression: nuclear (N) and cytoplasmic (C). The expression of N-CyclinD1 / C-CyclinD1 in FN (77.4%, 48/62; 50.0%, 31/62) was much higher than that in multinodular goiters with dominant nodules (MNG-DN) (16.4%, 10/61; 4.9%, 3/61) (p < 0.05). In contrast, the expression of D2–40 in MNG-DN (82.0%,50/61) was much higher than that in FN (4.8%, 3/62) (p < 0.05). In addition, unique staining patterns were observed: CyclinD1 showed no immunostaining only in all 8 cases of oncocytic cell tumors (OCT); D2–40 staining showed the characteristic wide distribution of lymphatic vessels in all 8 cases of poorly differentiated thyroid carcinoma (PDTC). Finally, the expression of CyclinD1 and D2–40 did not differ among follicular thyroid adenoma and follicular thyroid carcinoma / noninvasive follicular thyroid neoplasm with papillary-like nuclear features (p > 0.05). ConclusionsCyclinD1 and D2–40 are helpful diagnostic markers of FN, which can assist to discern FN from MNG-DN / OCT / PDTC.

Dysregulation of Amphiregulin stimulates the pathogenesis of cystic lymphangioma

Along with blood vessels, lymphatic vessels play an important role in the circulation of body fluid and recruitment of immune cells. Postnatal lymphangiogenesis commonly occurs from preexisting lymphatic vessels by sprouting, which is induced by lymphangiogenic factors such as vascular endothelial growth factor C (VEGF-C). However, the key signals and cell types that stimulate pathological lymphangiogenesis, such as human cystic lymphangioma, are less well known. Here, we found that mouse dermal fibroblasts that infiltrate to sponges subcutaneously implanted express VEGF-D and sushi, Von Willebrand factor type A, EGF, and pentraxin domain containing 1 (SVEP1) in response to PDGFRβ signal. In vitro, Pdgfrb knockout (β-KO) fibroblasts had reduced expression of VEGF-D and SVEP1 and overproduced Amphiregulin. Dysregulation of these three factors was involved in the cyst-like and uneven distribution of lymphatic vessels observed in the β-KO mice. Similarly, in human cystic lymphangioma, which is one of the intractable diseases and mostly occurs in childhood, fibroblasts surrounding cystic lymphatics highly expressed Amphiregulin. Moreover, fibroblast-derived Amphiregulin could induce the expression of Amphiregulin in lymphatic endothelial cells. The dual source of Amphiregulin activated EGFR expressed on the lymphatic endothelial cells. This exacerbation cascade induced proliferation of lymphatic endothelial cells to form cystic lymphangioma. Ultimately, excessive Amphiregulin produced by fibroblasts surrounding lymphatics and by lymphatic endothelial cells per se results in pathogenesis of cystic lymphangioma and will be a fascinating therapeutic target of cystic lymphangioma.

Optimal Surgery for Early Ampullary Carcinoma Based on a Pathological Examination Following Resection

Introduction: The aim of this study was to investigate whether partial resection (PR) instead of pancreaticoduedenectomy (PD) is acceptable for early (Tis-T1) ampullary carcinoma (AC). Methods: Of 101 patients who underwent resection for AC between January 1985 and December 2018, 40 patients with early AC (Tis: 2; T1a: 18; T1b: 20) and 16 patients treated with PR were assesed. In addition, the lymphatic vessel distribution in the ampulla of Vater was investigated immunohistologically using D2-40. Results: The 5-year survival rate was 100% and 87.4% in the Tis-T1a and T1b patients, respectively. On pathological examination, 10.0% (Tis-T1a: 0%; T1b: 20.0%) were lymph node (LN) metastasis (+), 20.0% (Tis-T1a: 0%; T1b: 40.0%) were lymphovascular invasion (+), 5.0% (Tis-T1a: 0%; T1b: 10.0%) were microvascular invasion (+), and 0% were perineural invasion (+). For the tumor differentiation, papillary or well differentiated tumors were found in all Tis-T1a patients, but moderate in 35.0% of the T1b patients. On immunohistological examination, abundant capillary lymphatic vessels were present in the mucosa of the ampulla of Vater. In the 16 patients treated with PR, the final pathological diagnosis was T1a in 12, pT1b in 1, and pT2 in 3, and the 4 non-T1a patients all died of recurrence. Conclusions: For T1b AC, PD may be the standard treatment because of the frequencies of LN metastasis and lymphovascular invasion. Abundant lymphatic capillaries in the mucosa of the ampulla of Vater and difficulty with preoprative diagnosis of the invasion depth indicate that PR may not be acceptable for Tis-T1a AC.

Alfred Biesiadecki (1839-1889) and his place in the history of dermatology

Modern dermatology, as a separate branch of medicine, came into being in the 19th century. Alfred Biesiadecki was an outstanding anatomic pathologist and the pioneer in the histopathologic examination of the skin. Biesiadecki was the first to describe the exact distribution of lymphatic vessels in the skin. He dealt with the histopathologic mechanisms of dermatitis and skin grafts, and his work was the forerunner of studies of neoplasms in the skin vasculature. His scientific achievements secured him a prominent place in the history of dermatology in Europe and around the globe. The present work outlines a biography of Alfred Biesiadecki and his most important studies of both dermatology and other branches of medicine.

Observation of the cytoarchitecture of the human esophageal mucosa with special attention to the lamina muscularis mucosae and the distribution of lymphatic vessels.

The cytoarchitecture of the esophageal mucosa was examined by using light microscopy, transmission electron microscopy, and scanning electron microscopy. The cytoarchitecture of the muscularis mucosae varied greatly among the cervical, thoracic, and abdominal esophagus, especially in the cervical esophagus, the muscularis mucosae suffered a loss and the distribution of lymphatic vessels also varied according to the site. It was suggested that these morphological differences would have a strong influence on the infiltration of esophageal cancer and the mode of lymph node metastasis.

Abnormal lymphatic vessel development is associated with decreased decidual regulatory T cells in severe preeclampsia.

The lymphatic vasculature controls leukocytes trafficking and limits the adaptive immune response. In previous models of preeclampsia (PE), defective immune function caused by disruption of lymphangiogenesis was shown to be involved in the disease pathophysiology. Especially, the dysfunction of regulatory T cells (Treg) at the maternal-fetal interface may be one of the causes of severe PE. In particular, activation of Tregs to obtain immune tolerance requires adequate antigen presentation through the lymphatic system. We hypothesized that impaired lymphangiogenesis and imbalanced Tregs at the maternal-fetal interface are associated with the pathophysiology of severe PE. However, the current research addressing this hypothesis is limited. Therefore, to compare differences in lymphangiogenesis in severe PE and normal conditions, we aimed to examine the location of lymphatics at the maternal-fetal interface and to investigate the association between lymphangiogenesis and Tregs in severe PE. We obtained entire uterus from normal pregnant mice. Placental and fetal membranes, including decidua, were obtained from 10 pregnant women with severe PE and 10 gestational age-matched controls. Immunohistochemistry for LYVE1 was used to localize the distribution of lymphatic vessels and CD4, CD25, and FOXP3 for Treg. LYVE1-positive vessels were present in the uterine wall of mice. LYVE1-positive lymphatic vessels were localized on the human decidua. Tubular lymphatics were abundant in the control decidua, but significantly reduced in severe PE. Furthermore, lymphatic vessel density correlated with the number of decidual Tregs. Abnormal decidual lymphangiogenesis is associated with reduced numbers of decidual Tregs in severe PE.

Aspects of lymphatic vessel configuration of the human male urinary bladder and adjacent organs: A histological basis for understanding the spread of cancer metastases

PurposeThe spread of cancer cells via lymphatic vessels (LVs) is supposed to be an early event in the dissemination process of bladder cancer metastasis. However, the configuration of LVs in the human bladder has not been extensively examined microscopically. Therefore the distribution of LVs in the bladder was investigated. Materials and methodsUsing D2-40 immunohistochemistry labeling, LVs of bladders and adjacent organs obtained from 10 donated male cadavers, in which the bladders were not dilated post mortem. ResultsThe bladder smooth muscle layer contained abundant dilated LVs, especially close to the center of the thickness of the bladder body wall. The LVs also made a delicate network in the mucosal tissue, although the density was lower than that in the smooth muscle layer. Independent from the artery and vein, LVs ran along and bundled the smooth muscles. Externally, LVs tended to run in parallel with longitudinal smooth muscles of the outer walls, especially at the posterior surface near the bladder neck. Additional LVs were traced in adjacent organs: prostate, seminal vesicles and rectum. ConclusionsThe present study indicates that clinical interventions should be attentive with the treatment of bladder cancer patients, especially considering the bladder neck or trigone area, to prevent the spread of cancer cells via LVs.

Teaching Palmar Anatomy: A Comparative Case Study of Conventional Scalpel Dissection With an Innovative Hydro‐dissection Method

We present a comparative case study of two dissection methods for teaching palmar anatomy: 1) an innovative hydro‐dissection method using water and brushes, and 2) conventional scalpel dissection. The objective was to compare the visibility of palmar structures for students using the two methods. Conventional dissection methods used to study the palmar aspect of the hand are difficult for students, due to the thickness of the skin firmly bound to the palmar aponeurosis and the drying of tissue layers in the course of dissection. This difficulty complicates students' observation of key structures in the hand, such as nerve innervations and deep fascia. A method of hydro‐dissection we have developed based on descriptions found in an ancient Indian surgical Āyurvedic treatise, the Susruta Saṃhitā, is tested here as an alternative method. The hand dissected using the hydro‐dissection method was soaked for seven days in a six‐liter tank filled with distilled water moving at a constant velocity. Subsequently, the students used special blunt metal brushes designed for this technique, for peeling and scraping the tissue while the hand was submerged. The second hand was dissected using conventional scalpel cutting dissection methods. These two processes are presented with documentation and photographs showing the structures visible over time during the course of both dissection processes. The results were that superficial fascia, the venous network, the lymphatic vessel distribution, the superficial branching of the radial nerve and ulnar nerve were more clearly visible in the hand that had undergone hydro‐dissection. The fascial compartments, short muscles of thumb and little finger, deep and superficial branches of ulnar nerve, deep and superficial palmar arch, and retinaculum were identified by the students more easily in the course of hydro‐dissection, due to the ease of tracing in comparison with the conventional method. The fibrous sheath expansions of both the flexor and extensor expansions could be identified using this method without a high‐level of skill and experience in dissection. Students were also able to make clearer identification of ligaments because they are not cut in the process. Movements of the digits was easier because the tissues were well‐moistened throughout the study. Articular study of the palm with the major and minor joints was also simplified since hydration in hydro‐dissection preserved the capsules and tiny ligaments from the usual damages occurring during blade dissection. In conclusion, hydro‐dissection is an effective blunt dissection method for students studying palmar anatomy and, we suggest, also for plantar anatomy. This method is particularly effective for entry‐level students without a high level of skill in dissection. We are currently working to develop a hydro‐dissection machine to standardize water quality, temperature, pressure, and flow, so that we can test this method on other structures and eventually develop an atlas and manual of hydro‐dissection. This study demonstrates the efficacy of hydro‐dissection for teaching structures in the palmar aspect of the hand.Support or Funding InformationGovernment Ayurveda Medical College ThiruvananthapuramThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Lymphatic vessels: an emerging actor in atherosclerotic plaque development.

Atherosclerosis is a chronic inflammatory disease of large- to medium-sized arteries and is the main underlying cause of death worldwide. The lymphatic vasculature is critical for processes that are intimately linked to atherogenesis such as the immune response and cholesterol metabolism. However, whether lymphatic vessels truly contribute to the pathogenesis of atherosclerosis is less clear despite increasing research efforts in this field. PubMed and Ovid MEDLINE databases were searched. In addition, key review articles were screened for relevant original publications. Current knowledge about lymphatic vessels in the arterial wall came from studies that examined the presence and location of such vessels in human atherosclerotic plaque specimens, as well as in a variety of arteries in animal models for atherosclerosis (e.g. rabbits, dogs, rats and mice). Generally, three experimental approaches have been used to investigate the functional role of plaque-associated lymphatic vessels; experimental lymphostasis was used to investigate lymphatic drainage of the arterial wall, and more recently, studies with genetic interventions and/or surgical transplantation have been performed. Lymphatic vessels seem to be mostly present in the adventitial layer of the arterial walls of animals and humans. They are involved in reverse cholesterol transport from atherosclerotic lesions, and arteries with a dense lymphatic network seem naturally protected against atherosclerosis. Lymphangiogenesis is a process that is an important part of the inflammatory loop in atherosclerosis. However, how augmenting or impeding the distribution of lymphatic vessels impacts disease progression remains to be investigated in future studies.

A New Technique to Map the Lymphatic Distribution and Alignment of the Penis.

The present study was to examine the distribution of lymphatic vessels in the penis of normal adult males, which could provide an anatomical basis for improvement of incisions in penile lengthening surgery, and may also help to prevent postoperative refractory edema. Thirteen normal adult male volunteers were recruited for this study. Contrast agent was injected subcutaneously in the foreskin of the penis, and after two minutes magnetic resonance lymphangiography (MRL) was performed. The acquired magnetic resonance images were analyzed to determine the changes in the number and diameter of lymphatic vessels in different parts of the penis. Maximum intensity projections (MIP) and materializes interactive medical image control system (MIMICS) were applied to analyze the overall distribution of lymphatic vessels in the penis. Magnetic resonance imaging (MRI) showed that the lymphatic vessels were in conspicuous contrast with surrounding tissues and could be clearly identified. Penile lymphatic vessels were clearly visible in the root of the penis. At the junction of the penis and the abdominal wall, all lymphatic vessels were found to be concentrated in the dorsal part of the penis. MIP two-dimensional reconstruction showed that the overall distribution of relatively large lymphatic vessels in the dorsal and ventral parts of the penis could be seen clearly on bilateral 45° position, but not inside the abdominal wall because some of lymphatic vessels were overlapped by other tissues in the abdomen. MIMICS three-dimensional reconstruction was able to reveal the overall spatial distribution of lymphatic vessels in the penis from any angle. The reconstruction results showed that there were 1-2 main lymphatic vessels on the root of dorsal penis, which coursed along the cavernous to the first physiological curvature of the penis. Lymphatic vessels merged on both sides of the ventral penis. At the root of the penis, lymphatic vessels gradually coursed to the dorsal surface of the penis and folded at the abdominal wall to the outside, and finally merged into the inguinal lymph nodes. The changes in distribution, number and diameter of the lymphatic vessels in the penis were observed by MRI. MIP and MIMICS reconstructions directly revealed the anatomical features of penile lymphatic vessels such as spatial distribution, overall alignment, and the relations to adjacent structures, drainage and reflux. The study will provide the anatomical basis for penile surgery, penile lymphatic reflux disorders caused by trauma or lymphatic vessels obstruction, and lymph node metastasis in penile cancer.

A detailed appraisal of mesocolic lymphangiology--an immunohistochemical and stereological analysis.

Inadequate resection of the adjoining mesentery is associated with adverse outcome for colon cancer. Disruption of the integrity of the mesenteric lymphatic package has been implicated in this, though not proven. Recent studies have determined mesenteric anatomy and histology and now provide an opportunity to determine accurately the distribution of lymphatic vessels. The aim of this study was to characterise the distribution of the lymphatic vessels (LV) within the small intestinal and colonic mesentery, and in Toldt's fascia, which lies between the mesocolon and underlying retroperitoneum. Mesenteric samples were harvested from 12 human cadavers. Samples were taken from the small bowel mesentery, ascending, transverse, descending mesocolon and from both apposed and non-apposed portions of the mesosigmoid. Serial sections were stained immunohistochemically with monoclonal antibody D2-40 (podoplanin), and Masson's Trichrome. Lymphatic vessel (LV) density and radius of diffusion were determined using a stereological approach. A lymphatic network was embedded within the mesenteric connective tissue lattice throughout each mesenteric region. LV were identifiable within the submesothelial connective tissue where they measured 10.2 ± 4.1 μm in diameter and had an average radius of diffusion of 174.72 ± 97.68 μm. Unexpectedly, LV were identified in Toldt's fascia, where they measured 4.3 ± 3.1 μm in diameter and had a radius of diffusion of 165.12 ± 66.26 μm. This is the first study systematically to determine and quantify the distribution of lymphatic vessels within the mesenteric organ and to demonstrate the presence of such vessels within Toldt's fascia. A rich lymphatic network occupies all levels of the mesenteric connective tissue lattice. Within the latter, they are found within 0.1 mm of peritonealised mesenteric surfaces and are separated by an average distance of 0.17 mm and may be particularly vulnerable during surgery.

Improved computer-assisted analysis of the global lymphatic network in human cervical tissues

Lymphatic dissemination is a key event in cervical cancer progression and related tumor lymphatic markers are viewed as promising prognostic factor of nodal extension. However, validating such parameters requires an objective characterization of the lymphatic vasculature. Here, we performed a global analysis of the lymphatic network using a new computerized method applied on whole uterine cervical digital images. Sixty-eight cases of cervical neoplasia (12 CIN3, 10 FIGO stage 1A and 46 stage IB1) and 10 cases of normal cervical tissue were reacted with antibodies raised against D2-40, D2-40/p16 and D2-40/Ki67. Immunostained structures were automatically detected on whole slides. The lymphatic vessel density (D2-40), proliferating lymphatic vessel density (D2-40/ki67) and spatial lymphatic distribution in respect to the adjacent epithelium were assessed from normal cervix to early cervical cancer and correlated with lymphovascular space invasion and lymph node status. Prominent lymphatic vessel density and proliferating lymphatic vessel density are detected under the transformation zone of benign cervix and no further increase is noted during cancer progression. Notably, a shift of lymphatic vessel distribution toward the neoplastic edges is detected. In IB1 cervical cancer, although intra- and peritumoral lymphatic vessel density are neither correlated with lymphovascular space invasion nor with lymph node metastasis, a specific spatial distribution with more lymphatic vessels in the vicinity of tumor edges is predictive of lymphatic dissemination. Herein, we provide a new computerized method suitable for an innovative detailed analysis of the lymphatic network. We show that the transformation zone of the benign cervix acts as a baseline lymphangiogenic niche before the initiation of neoplastic process. During cancer progression, this specific microenvironment is maintained with lymphatic vessels even in closer vicinity to tumor cells.

Lymphatic and nerve distribution throughout the parametrium

BackgroundOur objective was to concomitantly assess distribution of lymphatic and nerve structures in the parametrium. MethodsTwenty hemipelvises from ten fresh cadavers were dissected to differentiate between, three different parts of the parametrium: the lateral parametrium, the proximal and the distal part of the posterior parametrium. Histologic and immunofluorescence analyses of nerve and lymphatic structures were performed using NSE and LYVE-1 staining, respectively. The percentage of structures was independently scored as 0 (0%), 1 (1–20%), 2 (20–50%), 3 (50–80%), 4 (>80%). ResultsThe lateral parametrium and the proximal part of the posterior parametrium contained both nerve (scored 2.25 and 2.50, respectively) and lymphatic (scored 2.50 and 2.00, respectively) structures. The distal part of the posterior parametrium also contained numerous nerve structures (scored 2.00) but lymphatic structures were rare (scored 0.88). No difference in nerve distribution was found according to the parts of parametrium while a significantly lower distribution of lymphatic vessels was observed in the distal part of the posterior parametrium (p=0.03). ConclusionThe distal part of the posterior parametrium is of high nerve density and low lymphatic density raising the issue as to whether it should be removed during radical hysterectomy.

Microscopic analysis of lymphatic vessels in primary lymphedematous skin

ZusammenfassungHintergrund: Obwohl das Lymphsystem der Haut bei den primären Lymphödemen einbezo-gen ist, werden die Morphologie und die An-ordnung der Lymphgefäße in der betroffenen Hautregion der unteren Extremität bei dieser Krankheit wenig beschrieben und verstanden. Unser Ziel war es, die strukturellen und räumlichen Eigenschaften der Lymphgefäße in der be-troffenen Hautregion der unteren Extremität bei Patienten mit primären Lymphödemen zu charakterisieren und ihre Rolle bei dieser Krankheit herauszuarbeiten.Methoden: Es wurden Hautbiopsien der unteren Extremität von 14 Patienten mit primärem Lymphödem sowie von 10 altersmäßig ent-sprechenden Kontrollen entnommen und immunhistochemisch sowie mikroskopischeuntersucht unter Verwendung von podoplanin-Antikörpern (einem lymphatischen Marker). Die Lymphgefäße jedes Abschnittes wur-den gezählt und der innere luminale Durchmesser bestimmt.Ergebnisse: Die Gesamtdichte und der innere luminale Durchmesser der Lymphgefäße in der betroffenen Haut der untereren Extremität der Patienten mit primärem Lymph-ödem waren verglichen mit Kontrollen größer (p=0,004 bzw. p=0,014 ). Im oberen Bereich der Lederhaut bis 300 μm war die Dichte der Lymphgefäße der Lymphödem-Patienten niedriger im Vergleich zu den Kontrollen (p=0,00). Demgegenüber war die Dichte der Lymphgefäße in der tiefen Lederhaut (&gt;300 μm) bei primärem Lymphödem höher als bei den Kontrollen (p=0,00).Zusammenfassung: Die betroffene Haut der unteren Extremität der Primärlymphödem-Pa-tienten wird gekennzeichnet durch die Hyper-plasie und Dilatation von Lymphvasculaturen hauptsächlich in der tiefen Lederhaut, was auf eine pathogene Rolle bei der Entstehung und der klinischen Manifestation der Krankheit hindeuten könnte.