Lymphatic Distribution Research Articles

Lymphatic Channel Distribution in Comparison With Blood Vessels in the Upper Eyelid.

To examine microscopically the distribution of the lymphatic channels in comparison with the blood vessels in the upper eyelid. Central sagittal sections of 13 upper eyelids (8 right, 5 left) from 11 Japanese cadavers, aged 36 to 87 years old (average age: 66.6 years), were histologically examined. The specimens were fixed in 10% formalin. Staining with D2-40 for lymphatic channels and with the antibody for α-smooth muscle actin for blood vessels was utilized. The lymphatic channels were mainly distributed superficially, just under the skin, but the blood vessels were situated deeper, and diffusely spread throughout the upper eyelid. The positional predispositions of the lymphatic channels and the blood vessels were different. The former is mainly superficial and the latter is deeper and diffuse.

Volumetric imaging of the tumor microvasculature reflects outcomes and genomic states of clear cell renal cell carcinoma.

Tumor structure is heterogeneous and complex, and it is difficult to obtain complete characteristics by two-dimensional analysis. The aim of this study was to visualize and characterize volumetric vascular information of clear cell renal cell carcinoma (ccRCC) tumors using whole tissue phenotyping and three-dimensional light-sheet microscopy. Here, we used the diagnosing immunolabeled paraffin-embedded cleared organs pipeline for tissue clearing, immunolabeling, and three-dimensional imaging. The spatial distributions of CD34, which targets blood vessels, and LYVE-1, which targets lymphatic vessels, were examined by calculating three-dimensional density, vessel length, vessel radius, and density curves, such as skewness, kurtosis, and variance of the expression. We then examined those associations with ccRCC outcomes and genetic alteration state. Formalin-fixed paraffin-embedded tumor samples from 46 ccRCC patients were included in the study. Receiver operating characteristic curve analyses revealed the associations between blood vessel and lymphatic vessel distributions and pathological factors such as a high nuclear grade, large tumor size, and the presence of venous invasion. Furthermore, three-dimensional imaging parameters stratified ccRCC patients regarding survival outcomes. An analysis of genomic alterations based on volumetric vascular information parameters revealed that PI3K-mTOR pathway mutations related to the blood vessel radius were significantly different. Collectively, we have shown that the spatial elucidation of volumetric vasculature information could be prognostic and may serve as a new biomarker for genomic alterations. High-end tissue clearing techniques and volumetric immunohistochemistry enable three-dimensional analysis of tumors, leading to a better understanding of the microvascular structure in the tumor space.

Biochemical and Histological Differences between Longitudinal and Vertical Fibres of Dupuytren's Palmar Aponeurosis and Innovative Clinical Implications.

Dupuytren's disease, a chronic and progressive fibroproliferative lesion of the hand, which affects the palmar fascia, has a recurrence rate after selective aponeurotomy of 20-40% at 5 years. This study focused, for the first time, on the microanatomical and histopathological characteristics of the longitudinal and vertical fibres (usually spared during surgery) in the aponeurosis with Dupuytren's disease, in different stages of the Tubiana's classification. Twelve human samples were collected and analysed by immunostaining, Total Collagen Assay, ELISA Immunoassay, and immunoblotting for the Von Willebrand factor, α-Sma, D2-40, CD-68, Total Collagen, Collagen-I and III, IL1β, TNF-α to analyse the blood and lymphatic vascularization, the amount and distribution of collagen, and the inflammation. The results show a progressive increase in the arterial vascularization in the vertical fibres (from 8.8/mm2 in the early stage to 21.4/mm2 in stage 3/4), and a parallel progressive decrease in the lymphatic drainage (from 6.2/mm2 to 2.8/mm2), correlated with a local inflammatory context (increase in IL-1β and TNF-α until the stage 2) in both the longitudinal and vertical fibres. The acute inflammation after stage 2 decreased, in favour of a fibrotic action, with the clear synthesis of new collagen (up to ~83 µg/mg), especially Collagen-I. These results clearly demonstrate the involvement of the septa of Legueu and Juvara in the disease pathology and the modifications with the disease's progression. A greater understanding of the pathology becomes fundamental for staging and the adequate therapeutic timing, to obtain the best morpho-functional result and the lowest risk of complications.

Quantification of Lymphangiogenesis in the Murine Lymphedema Tail Model Using Intravital Microscopy.

Background: Lymphedema is chronic limb swelling resulting from lymphatic dysfunction. It affects an estimated five million Americans. There is no cure for this disease. Assessing lymphatic growth is essential in developing novel therapeutics. Intravital microscopy (IVM) is a powerful imaging tool for investigating various biological processes in live animals. Tissue nanotransfection technology (TNT) facilitates a direct, transcutaneous nonviral vector gene delivery using a chip with nanochannel poration in a rapid (<100 ms) focused electric field. TNT was used in this study to deliver the genetic cargo in the murine tail lymphedema to assess the lymphangiogenesis. The purpose of this study is to experimentally evaluate the applicability of IVM to visualize and quantify lymphatics in the live mice model. Methods and Results: The murine tail model of lymphedema was utilized. TNT was applied to the murine tail (day 0) directly at the surgical site with genetic cargo loaded into the TNT reservoir: TNTpCMV6 group receives pCMV6 (expression vector backbone alone) (n = 6); TNTProx1 group receives pCMV6-Prox1 (n = 6). Lymphatic vessels (fluorescein isothiocyanate [FITC]-dextran stained) and lymphatic branch points (indicating lymphangiogenesis) were analyzed with the confocal/multiphoton microscope. The experimental group TNTProx1 exhibited reduced postsurgical tail lymphedema and increased lymphatic distribution compared to TNTpCMV6 group. More lymphatic branching points (>3-fold) were observed at the TNT site in TNTProx1 group. Conclusions: This study demonstrates a novel, powerful imaging tool for investigating lymphatic vessels in live murine tail model of lymphedema. IVM can be utilized for functional assessment of lymphatics and visualization of lymphangiogenesis following gene-based therapy.

Clinical Effectiveness of Fluorescence Lymph Node Mapping Using ICG for Laparoscopic Right Hemicolectomy: A Prospective Case-Control Study.

The distinction between D3 lymph nodes and actual lymphatic pathways in primary tumors can be difficult during surgery, making it challenging to confirm the completeness of D3 lymph node dissection. Fluorescence lymph node mapping (FLNM) is a promising method for lymph node visualization. This study aimed to assess whether FLNM enhances the effectiveness of D3 lymph node dissection in patients with right-sided colon cancer. Endoscopic submucosal indocyanine green injection were performed on the distal margin of the colon cancer. In an FLNM group, the lymphatic drainage pathway and distribution of D3 lymph nodes were explored. Pathological evaluations were conducted for the fluorescent D3 and non-fluorescent D3 lymph nodes. The FLNM group showed a significantly higher number of harvested lymph nodes in the D3 area. In stage III patients, the proportion of D3 lymph node metastasis was significantly higher in the FLNM group. The harvested D3 lymph node count showed a proportional correlation with a metastatic lymph node count of up to 15. FLNM could be considered a promising new strategy to potentially increase harvested D3 lymph node counts in colon cancer surgery.

Socio-economic and environmental factors associated with high lymphatic filariasis morbidity prevalence distribution in Bangladesh.

Lymphatic filariasis (LF) is a vector-borne parasitic disease which affects 70 million people worldwide and causes life-long disabilities. In Bangladesh, there are an estimated 44,000 people suffering from clinical conditions such as lymphoedema and hydrocoele, with the greatest burden in the northern Rangpur division. To better understand the factors associated with this distribution, this study examined socio-economic and environmental factors at division, district, and sub-district levels. A retrospective ecological study was conducted using key socio-economic (nutrition, poverty, employment, education, house infrastructure) and environmental (temperature, precipitation, elevation, waterway) factors. Characteristics at division level were summarised. Bivariate analysis using Spearman's rank correlation coefficient was conducted at district and sub-district levels, and negative binomial regression analyses were conducted across high endemic sub-districts (n = 132). Maps were produced of high endemic sub-districts to visually illustrate the socio-economic and environmental factors found to be significant. The highest proportion of rural population (86.8%), poverty (42.0%), tube well water (85.4%), and primary employment in agriculture (67.7%) was found in Rangpur division. Spearman's rank correlation coefficient at district and sub-district level show that LF morbidity prevalence was significantly (p<0.05) positively correlated with households without electricity (district rs = 0.818; sub-district rs = 0.559), households with tube well water (sub-district rs = 0.291), households without toilet (district rs = 0.504; sub-district rs = 0.40), mean annual precipitation (district rs = 0.695; sub-district rs = 0.503), mean precipitation of wettest quarter (district rs = 0.707; sub-district rs = 0.528), and significantly negatively correlated with severely stunted children (district rs = -0.723; sub-district rs = -0.370), mean annual temperature (district rs = -0.633.; sub-district rs = 0.353) and mean temperature (wettest quarter) ((district rs = -0.598; sub-district rs = 0.316) Negative binomial regression analyses at sub-district level found severely stunted children (p = <0.001), rural population (p = 0.002), poverty headcount (p = 0.001), primary employment in agriculture (p = 0.018), households without toilet (p = <0.001), households without electricity (p = 0.002) and mean temperature (wettest quarter) (p = 0.045) to be significant. This study highlights the value of using available data to identify key drivers associated with high LF morbidity prevalence, which may help national LF programmes better identify populations at risk and implement timely and targeted public health messages and intervention strategies.

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.

PC8. Prophylactic Axillary Lymphovenous Bypass Using the Branched Vein Graft Technique

PURPOSE: Prophylactic lymphovenous bypass reduces the risk of lymphedema after axillary lymph node dissection (ALND). Extensive axillary dissection often creates a large gap between disrupted lymphatic vessels and potential recipient veins. The wide distribution of lymphatics throughout the lateral axilla further compounds the difficulty of including all injured vessels for bypass. We describe the technical details and preliminary clinical outcomes of patients who underwent prophylactic lymphovenous bypass using a branched vein graft (BVG) from the superficial circumflex iliac vein (SCIV). METHODS: A retrospective review was performed, focusing on operative details and clinical results. Technique: A 8-10 cm BVG containing valves is harvested from the SCIV and coupled to an appropriate recipient vein. A 27-gauge cannula is used to intubate the BVG lumen at various branch openings as appropriate. This allows a 10-0 suture to be passed outward through the cannula. Lymphatic vessels are then captured and intussuscepted into the BVG with 4 - 6 mm of overlap, without any bunching or kinking. Upon completing the bypass, the intussuscepting suture is removed to avoid lymphatic obstruction. Valves in the graft prevent reflux. RESULTS: Seven patients were identified for inclusion. A median of 3 disrupted lymphatic vessels were encountered per case (range 1-5). Follow-up was 3 weeks to 6 months. Six patients demonstrated no clinical evidence of lymphedema. 1 patient had trace swelling localized to the thumb at 2 months. CONCLUSION: The branched vein graft technique effectively facilitates the immediate bypass of multiple injured lymphatics over a wide area after ALND.

MR lymphangiography of lymphatic abnormalities in children and adults with Noonan syndrome

Noonan syndrome is associated with complex lymphatic abnormalities. We report dynamic-contrast enhanced MR lymphangiography (DCMRL) findings in children and adults with Noonan syndrome to further elucidate this complex disease spectrum. A retrospective evaluation of patients with confirmed Noonan syndrome and clinical signs of lymphatic dysfunction undergoing DCMRL between 01/2019 and 04/2021 was performed. MRL included T2-weighted imaging (T2w) and DCMRL. Clinical history/presentation and genetic variants were recorded. T2w-imaging was evaluated for central lymphatic abnormalities and edema distribution. DCMRL was evaluated regarding the presence of cisterna chyli/thoracic duct, lymphatic leakages, pathological lymphatic reflux and abnormal lymphatic perfusion. The time from start of contrast-injection to initial enhancement of the thoracic duct venous junction was measured to calculate the speed of contrast propagation. Eleven patients with Noonan syndrome with lymphatic abnormalities (5 female, 6 male; 7 infants, 4 adults; mean age 10.8 ± 16.4 years) were identified (PTPN11 n = 5/11 [45.5%], RIT1 n = 5/11 [45.5%], KRAS n = 1/11 [9%]). Patients had a chylothorax (n = 10/11 [91%]) and/or pulmonary lymphangiectasia [dilated pulmonary lymph vessels] (n = 9/11 [82%]). Mediastinal/pulmonary edema was depicted in 9/11 (82%) patients. The thoracic duct (TD) was (partially) absent in 10/11 (91%) cases. DCMRL showed lymphatic reflux into intercostal (n = 11/11 [100%]), mediastinal (n = 9/11 [82%]), peribronchial (n = 8/11 [73%]), peripheral (n = 5/11 [45.5%]) and genital lymphatics (n = 4/11 [36%]). Abnormal pulmonary/pleural lymphatic perfusion was seen in 8/11 patients (73%). At infancy peripheral/genital edema was more prevalent in patients with RIT1 than PTPN11 (n = 3/5 vs. n = 0/5). Compared to patients with PTPN11 who had fast lymphatic enhancement in 4/5 patients, enhancement took markedly longer in 4/5 patients with RIT1-mutations. Thoracic duct dysplasia, intercostal reflux and pulmonary/pleural lymphatic perfusion are characteristic findings in patients with Noonan syndrome presenting with chylothorax and/or pulmonary lymphangiectasia. Central lymphatic flow abnormalities show possible phenotypical differences between PTPN11 and RIT1-mutations.

Periostin in lymph node pre-metastatic niches governs lymphatic endothelial cell functions and metastatic colonization

Although lymph node (LN) metastasis is an important prognostic parameter in cervical cancer, the tissue remodeling at a pre-metastatic state is poorly documented in LNs. We here identified periostin (POSTN) as a component of non-metastatic LNs by applying proteomic analyses and computerized image quantifications on LNs of patients with cervical cancer. We provide evidence for remarkable modifications of POSTN and lymphatic vessel distributions and densities in non-metastatic sentinel and metastatic human LNs, when compared to distant non-metastatic LNs. POSTN deposition at a pre-metastatic stage was demonstrated in a pre-clinical murine model (the ear sponge assay). Its expression by fibroblastic LN cells was assessed by in situ hybridization and in vitro cultures. In vitro, POSTN promoted lymphatic endothelial cell functions and tumor cell proliferation. Accordingly, the in vivo injection of recombinant POSTN together with VEGF-C boosted the lymphangiogenic response, while the metastatic potential of tumor cells was drastically reduced using a POSTN blocking antibody. This translational study also supports the existence of an unprecedented dialog “in cascade”, between the primary tumor and the first pelvic nodal relay in early cervical cancer, and subsequently from pelvic LN to para-aortic LNs in locally advanced cervical cancers. Collectively, this work highlights the association of POSTN deposition with lymphangiogenesis in LNs, and provides evidence for a key contribution of POSTN in promoting VEGF-C driven lymphangiogenesis and the seeding of metastatic cells.

Postoperative lymphatic recurrence distribution and delineation of the radiation field in lower thoracic squamous cell esophageal carcinomas: a real-world study

BackgroundTo study lymphatic recurrence distribution after radical surgery in the real world and guide clinical tumor volume delineation for regional lymph nodes during postoperative radiotherapy for lower thoracic squamous cell esophageal carcinomas.MethodsWe enrolled patients who underwent radical esophagectomy, without radiation before or after surgery, at 3 cancer hospitals. Patients were classified into groups according to tumor locations. We included patients with tumors in the lower thoracic segment and analyzed the postoperative lymph node recurrence mode. A cutoff value of 10% was used to differentiate high-risk lymph node drainage areas from others.ResultsWe enrolled 1905 patients in the whole study series, including 652 thoracic esophageal carcinomas that met our inclusion criteria; there were 241 cases of lower thoracic esophageal carcinomas. 1st, 2nd, 4th, 7th, 8th groups of lymph nodes, according to the 8th edition of the AJCC classification, displayed as high-risk recurrence areas, representing 17.8%, 23.9%, 11.7%, 10.9% and 12.2% of lymph node recurrence. Stage III-IV tumors located in the lower segment of the thoracic esophagus showed a tendency to recur in the left gastric nodes (7.9%) and celiac nodes (10.6%).ConclusionsAccording to our results, we recommended including the 4th, 7th and 8th groups of lymph nodes in the radiation field, and for patients with stage III-IV disease, the 17th and 20th groups of nodes should be irradiated during postoperative treatment. Whether including 1st/2nd groups in preventive irradiation needed more proofs.

Methylene blue and carbon nanoparticles had no significant adverse effects on the survival and function of lymph nodes after non-vascularized transplantation in a mouse model

BackgroundLymph node transfer has been known as a physiologic approach for “curing” lymphedema. The transplantation of methylene blue and carbon nanoparticles stained lymph nodes aims to investigate their impact on the survival of transplanted lymph nodes. MethodsFour weeks after transplantation, the survival condition of transplanted lymph nodes was detected by the reconnection with lymphatics, reconnected lymphatic function, HE staining, and distribution of B-cells and T-cells. Also, the number of lymphatics (LYVE-1) and blood vessels (CD31) of transplanted lymph nodes was investigated. ResultsReconnected lymphatic function, the number of transplanted lymph nodes of achieving lymphatic reconstruction, and the surviving and potentially surviving ones were close. Besides, the control group (n = 11, CD31: mean = 9.527 ± 1.017, LYVE-1: mean = 21.45 ± 1.780), the methylene blue group (n = 12, CD31: mean = 9.73 ± 0.8998, LYVE-1: mean = 20.67 ± 1.601) and the carbon nanoparticles group (n = 11, CD31:mean = 8.709 ± 1.435, LYVE-1: mean = 19.60 ± 2.268). After calculation, both CD31 and LYVE-1 showed no significant difference statistically among the three groups. ConclusionsOur findings justify the use of methylene blue and carbon nanoparticles in reverse lymphatic mapping, as they can increase the efficiency of collecting “target lymph nodes” and minimize the iatrogenic injury in the donor area while having no significant adverse effects on the survival condition of transplanted lymph nodes. And this approach is easy to operate and worthy of clinical application and popularization.

Generalized lymphatic anomaly: an unusual cause of mediastinal widening -A case report

While simple lymphatic malformations which may be microcystic or macrocystic (Cystic hygroma) are quite common, complex lymphatic anomalies such as generalized lymphatic anomaly are uncommon. Due to its rarity and nonspecific presentation, diagnosis may often be delayed. A 7yr old male presented with non-specific respiratory symptoms and knee pain. Chest imaging findings of low attenuation soft tissue mass with infiltration along the lymphatic distribution adjacent to the bronchovascular bundles and multiple punched out lytic lesions in the bones with preserved cortex were seen. In the given clinical scenario, laboratory findings, these imaging findings were highly suggestive for generalised lymphatic anomaly.We suggest a complete radiological evaluation in such children as imaging can be highly suggestive even in the absence of genetic or histopathological diagnosis.

NPTD classification: an updated classification of gastric cancer location for function preserving gastrectomy based on physiological lymphatic flow

BackgroundThe correlation between tumor location and lymphatic flow distribution in gastric cancer has been previously reported, and PTD (Proximal – Transitional – Distal) classification was proposed. Our group updated and developed the nPTD classification.MethodWe retrospectively studied gastric cancer patients who underwent the dye method sentinel node biopsy from 1993 to 2020. The inclusion criteria were a single lesion type 0 cancer of ≤5 cm in the long axis, clinically node-negative, and invasion within the proper muscle layer pathologically. In this study, the distribution of dyed lymphatic flow was evaluated for each occupied area of the tumor.ResultsWe included 416 patients in this study. The tumors located in the watershed of the right and left gastroepiploic arteries near greater curvature had extensive lymphatic flow; therefore, a newly circular region with a diameter of 5 cm is set on the watershed of the greater curvature between P and T zone as the ‘n’ zone. In addition, for cancers located in the lesser P curvature, lymphatic flow to the greater curvature was not observed. Therefore, the P zone was divided into two: the lesser curvature side (PL) and the greater curvature side (PG).ConclusionsThe advantage of the nPTD classification is that it provides not only proper nodal dissection but also adequate function-preserving gastrectomy. If the tumor is localized within the PL, the proximal gastrectomy resection area can be further reduced. In contrast, for cancers located in the ‘n’ zone, near-total gastrectomy is required because of the extensive lymphatic flow.

Historical Review of Lymphatic Studies in the Hand

As a part of vascular systems, the lymphatic system was discovered later than the others. Initially lymphatic vessels were observed in the viscera of mammals. Lymphatic vessels of the human limbs were not found until the mercury injection technique was introduced, which were largely referred by later literature. However the knowledge sometimes does not match or explain some of the unexpected clinical findings. Although, the superficial lymphatic distribution of the upper limb has been updated during the last decade, but the deep lymphatic pathways of the hand were still remained in uncertainty till a recent article was reported. This review the current investigative approaches through the historical perspective for clinical management and scientific researches in this region.

Immune parameters in two different laying hen strains during five production periods

During life, the number and function of immune cells change with potential consequences for immunocompetence of an organism. In laying hens, studies have primarily focused on early development of immune competence and only few have investigated systemic and lymphatic distribution of leukocyte subsets during adolescence and the egg-laying period. The present study determined the number of various leukocyte types in blood, spleen, and cecal tonsils of 10 Lohmann Brown-Classic and 10 Lohmann LSL-Classic hens per wk of life 9/10, 15/16, 23/24, 29/30, and 59/60, encompassing important production as well as developmental stages, by flow cytometry. Although immune traits differed between the 2 hen strains, identical patterns of age-related immunological changes were found. The numbers of all investigated lymphocyte types in the spleen as well as the numbers of blood γδ T cells increased from wk 9/10 to 15/16. This suggests an ongoing release of lymphocytes from primary lymphoid tissues and an influx of blood lymphocytes into the spleen due to novel pathogen encounters during adolescence. A strong decrease in the number of CTL and γδ T cells and an increase in innate immune cells within blood and spleen were found between wk of life 15/16 and 23/24, covering the transition phase to egg-laying activity. Numbers of peripheral and splenic lymphocytes remained low during the egg-laying period or even further decreased, for example blood CD4+ T cells and splenic γδ T cells. Functional assessments showed that in vitro IFN-γ production of mitogen-stimulated splenocytes was lower in wk 60. Taken together, egg-laying activity seems to alter the immune system toward a more pronounced humoral and innate immune response, with probable consequences for the immunocompetence and thus for productivity, health and welfare of the hens.

Lymphatics in Eye Fluid Homeostasis: Minor Contributors or Significant Actors?

Simple SummaryThe eye contains fluid compartments whose tight regulation is essential for proper eye functioning. Lymphatic vessels are known to be important in several physiological functions including interstitial fluid homeostasis. Recent works has provided evidence of a potential role of lymphatic vessels in the drainage of ocular fluids. They may in particular contribute to the intraocular pressure regulation, whose increase is a major risk factor for the progression of glaucoma, an eye disease that can lead to blindness. They could also participate in the clearance of toxic waste products responsible for eye retinal neurodegenerative processes. In this review, we performed an update of ocular lymphatic vessel distribution, of their mechanisms of development and of their role in aqueous humor drainage and eye fluid regulation. We discussed these data and made some proposals to elucidate unresolved questions to improve knowledge concerning the lymphatic vessels roles in ocular fluid regulation, which could have repercussions in eye disease therapeutic strategies.Lymphatic vessels exert major effects on the maintenance of interstitial fluid homeostasis, immune cell trafficking, lipid absorption, tumor progression and metastasis. Recently, novel functional roles for the lymphatic vasculature have emerged, which can be associated with pathological situations. Among them, lymphatics have been proposed to participate in eye aqueous humor drainage, with potential consequences on intraocular pressure, a main risk factor for progression of glaucoma disease. In this review, after the description of eye fluid dynamics, we provide an update on the data concerning the distribution of ocular lymphatics. Particular attention is given to the results of investigations allowing the three dimensional visualization of the ocular surface vasculature, and to the molecular mechanisms that have been characterized to regulate ocular lymphatic vessel development. The studies concerning the potential role of lymphatics in aqueous humor outflow are reported and discussed. We also considered the novel studies mentioning the existence of an ocular glymphatic system which may have, in connection with lymphatics, important repercussions in retinal clearance and in diseases affecting the eye posterior segment. Some remaining unsolved questions and new directions to explore are proposed to improve the knowledge about both lymphatic and glymphatic system interactions with eye fluid homeostasis.

Oral delivery of topotecan in polymeric nanoparticles: Lymphatic distribution and pharmacokinetics

There have been many attempts to formulate a variety of drugs in nano-size formulations. However, biodistribution characteristics of these formulated drugs remain unclear. Information about the pharmacokinetics and distributions of these formulations is essential for future practical use and advanced formulation development. Topotecan is a useful agent for treating a variety of cancers. It exhibits anti-cancer activity by inhibiting topoisomerase. However, oral bioavailability of topotecan was not satisfactory in previous studies. Reversible hydrolysis of its active site according to pH environment was a major limitation in terms of treatment. To improve the bioavailability and retention of topotecan in target organs (such as lung and brain) and increase its delivery to the lymphatic system as a major pathway for cancer metastasis, this study was conducted on topotecan-loaded nanoparticles using poly(lactic-co-glycolic acid) (PLGA). These nanoparticles were prepared by double emulsion solvent evaporation. Formulated topotecan-loaded PLGA nanoparticles were subjected to several in vitro tests to determine various physicochemical properties such as size, zeta potential, encapsulation efficiency, morphology, and release profile. These nanoparticles were also subjected to in vivo studies using rats. Based on in vivo results, pharmacokinetic properties, distribution in the body, and delivery efficiency of these formulated nanoparticles were confirmed. Topotecan-loaded PLGA nanoparticles showed a delayed release pattern in vitro. Their pharmacokinetic profiles and distributions in the body were clearly different from those of free topotecan hydrochloride. Results confirmed that topotecan encapsulated in the PLGA polymer was stable from hydrolysis and present in an active form for a longer time in the body. Biometric imaging revealed in vivo properties of topotecan-loaded PLGA nanoparticles for qualitative confirmation. And oral delivery of topotecan in polymeric nanoparticles to lymph and various body tissues has been identified. Findings of this study indicate that topotecan formulated into nanoparticles (using PLGA) has a better pharmacokinetic profile and a better delivery to lymphoid tissues, lung, and brain than free topotecan hydrochloride, suggesting that these topotecan-loaded PLGA nanoparticles might provide better therapeutic results.

Pilot study supporting the existence of novel lymphatic channels within the canine anterior uveal tract using Lyve-1 and CD31.

To demonstrate the existence of lymphatics in the canine anterior uvea using lymphatic-specific markers Lyve-1, Prox-1, and podoplanin, the endothelial cell marker CD31, and basement membrane matrix marker collagen IV. Prospective Study. Eight normal globes from animals euthanized for unrelated health problems. Sagittally cut serial sections of six normal canine eyes were immunofluorescence double-stained with Lyve-1 and CD31 and single-stained with colorimetric Prox-1 and collagen IV. Three serial sections from 2 additional eyes were cut in the coronal plane at the level of the ciliary body and immunofluorescence double-stained with Lyve-1 and CD31 to map lymphatic channel distribution. Lymphatics from normal canine lymph nodes were used for validation of podoplanin. Four of 6 of the sagitally sectioned eyes had Lyve-1-positive lymphatic-like structures that were distinct from CD31-positive blood vessels in the iris base and ciliary body. Both of the coronally sectioned globes had Lyve-1-positive lymphatic-like structures in the ciliary body. The location of these structures was evaluated and found to be diffusely present circumferentially around the ciliary body. These results support the existence of lymphatic channels in the anterior uveal tract of the canine eye. This could indicate the presence of a novel uveolymphatic outflow pathway, which may play a role in aqueous humor outflow. Future studies are needed to confirm the existence and elucidate the role of this proposed uveolymphatic outflow pathway and potentially develop novel treatment options for managing glaucoma.

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.