Lymphatic Vessel Area Research Articles

Histological and biochemical changes in lymphatic vessels after skeletal muscle injury induced by lengthening contraction in male mice.

Lymphatic vessels are actively involved in the recovery process of inflamed tissues. However, the changes in intramuscular lymphatic vessels during inflammation caused by skeletal muscle injury remain unclear. Therefore, the purpose of this study was to clarify the changes in lymphatic vessels after skeletal muscle injury. The left tibialis anterior muscles of male mice were subjected to lengthening contractions (LC) for inducing skeletal muscle injury, and samples were collected on Days 2, 4, and 7 for examining changes in both the skeletal muscles and intramuscular lymphatic vessels. With hematoxylin-eosin staining, the inflammatory response was observed in myofibers on Days 2 and 4 after LC, whereas regeneration of myofibers was found on Day 7 after LC. The number and area of intramuscular lymphatic vessels analyzed by immunohistochemical staining with an antibody against lymphatic vessel endothelial hyaluronan receptor 1 were significantly increased only on Day 4 after LC. Based on the abovementioned results, intramuscular lymphatic vessels undergo morphological changes such as increase under the state of muscle inflammation. This study demonstrated that the morphology of intramuscular lymphatic vessels undergoes significant changes during the initial recovery phase following skeletal muscle injury.

Impact of intravenous/intranasal polyinosinic–polycytidylic acid administration on the mediastinal fat-associated lymphoid clusters and lung tissue in healthy mice

BackgroundPolyinosinic–polycytidylic acid (pIC) is a synthetic analog of double-stranded RNA. It is used as a synthetic adjuvant to induce an adaptive immune response. However, the effect of pIC on the development of mediastinal fat-associated lymphoid clusters (MFALCs) that regulate intrathoracic hemostasis has remained unidentified. MethodsWe investigated the impact of intranasal (i.n.) administration (pIC i.n. group) and intravenous (i.v.) administration (pIC i.v. group) of pIC on both MFALCs and lung tissue. ResultsCompared with the control phosphate-buffered saline (PBS) groups, both pIC-administered groups displayed a significant increase in the MFALC size (particularly in the pIC i.n. group), area of MFALC high endothelial venules (HEVs), area of lymphatic vessels (LVs), number of proliferating cells (particularly in the pIC i.v. group), and number of immune cells (B220+ B-lymphocytes, CD3+ T-lymphocytes, Iba1+ macrophages, and Gr-1+ granulocytes) in both MFALCs and lung tissues. In addition, a positive correlation was detected between MFALC size and proliferating cells, immune cell population, LVs, and HEVs within MFALCs in both groups. Except for the proliferating cell and B-lymphocyte populations in the i.n. administered group and granulocyte populations in both i.n. and i.v. administered routes, such correlations were significant. ConclusionIn all, our data indicate that local or systemic administration of pIC induces the development of MFALCs and can be used as an immunostimulant therapeutic strategy.

Inhibition of TP signaling promotes endometriosis growth and neovascularization.

Endometriosis is highly dependent on angiogenesis and lymphangiogenesis. Prostaglandin E2, an arachidonic acid metabolite, has been shown to promote the formation of new blood and lymphatic vessels. However, the role of another arachidonic acid metabolite, thromboxane A2 (TXA2) in angiogenesis and lymphangiogenesis during endometriosis remains largely unexplored. Using a murine model of ectopic endometrial transplantation, fragments from the endometrium of WT donor mice were transplanted into the peritoneal walls of recipient WT mice (WT→WT), resulting in an increase in both the area and density of blood and lymphatic vessels. Upon transplantation of endometrial tissue from thromboxane prostanoid (TP) receptor (TXA2 receptor)‑deficient (TP‑/‑) mice into TP‑/‑ mice (TP‑/‑→TP‑/‑), an increase in implant growth, angiogenesis, and lymphangiogenesis were observed along with upregulation of pro‑angiogenic and lymphangiogenic factors, including vascular endothelial growth factors (VEGFs). Similar results were obtained using a thromboxane synthase (TXS) inhibitor in WT→WT mice. Furthermore, TP‑/‑→TP‑/‑ mice had a higher number of F4/80+ cells than that of WT→WT mice, with increased expression of genes related to the anti‑inflammatory macrophage phenotype in endometrial lesions. In cultured bone marrow (BM)‑derived macrophages, the levels of VEGF‑A, VEGF‑C, and VEGF‑D decreased in a TP‑dependent manner. Furthermore, TP signaling affected the polarization of cultured BM‑derived macrophages to the anti‑inflammatory phenotype. These findings imply that inhibition of TP signaling promotes endometrial implant growth and neovascularization.

Thromboxane prostanoid signaling in macrophages attenuates lymphedema and facilitates lymphangiogenesis in mice : TP signaling and lymphangiogenesis.

Accumulating evidence suggests that prostaglandin E2, an arachidonic acid (AA) metabolite, enhances lymphangiogenesis in response to inflammation. However, thromboxane A2 (TXA2), another AA metabolite, is not well known. Thus, this study aimed to determine the role of thromboxane prostanoid (TP) signaling in lymphangiogenesis in secondary lymphedema. Lymphedema was induced by the ablation of lymphatic vessels in mouse tails. Compared with wild-type mice, tail lymphedema in Tp-deficient mice was enhanced, which was associated with suppressed lymphangiogenesis as indicated by decreased lymphatic vessel area and pro-lymphangiogenesis-stimulating factors. Numerous macrophages were found in the tail tissues of Tp-deficient mice. Furthermore, the deletion of TP in macrophages increased tail edema and decreased lymphangiogenesis and pro-lymphangiogenic cytokines, which was accompanied by increased numbers of macrophages and gene expression related to a pro-inflammatory macrophage phenotype in tail tissues. In vivo microscopic studies revealed fluorescent dye leakage in the lymphatic vessels in the wounded tissues. The results suggest that TP signaling in macrophages promotes lymphangiogenesis and prevents tail lymphedema. TP signaling may be a therapeutic target for improving lymphedema-related symptoms by enhancing lymphangiogenesis.

Therapeutic Potential of the Prolyl Hydroxylase Inhibitor Roxadustat in a Mouse Hindlimb Lymphedema Model.

Background: Lymphedema is an intractable disease with no curative treatment available. Conservative treatment is the mainstay, and new drug treatment options are strongly needed. The purpose of this study was to investigate the effect of roxadustat, a prolyl-4-hydroxylase inhibitor, on lymphangiogenesis and its therapeutic effect on lymphedema in a radiation-free mouse hindlimb lymphedema model. Methods and Results: Male C57BL/6N mice (8-10 weeks old) were used for the lymphedema model. Mice were randomized to an experimental group receiving roxadustat or a control group. The circumferential ratio of the hindlimbs was evaluated, and lymphatic flow of the hindlimbs was compared by fluorescent lymphography up to 28 days postoperatively. The roxadustat group showed an early improvement in hindlimb circumference and stasis of lymphatic flow. The number and area of lymphatic vessels on postoperative day 7 were significantly larger and smaller, respectively, in the roxadustat group compared with the control group. Skin thickness and macrophage infiltration on postoperative day 7 were significantly reduced in the roxadustat group compared with the control group. The relative mRNA expression of hypoxia-inducible factor-1α (Hif-1α), vascular endothelial growth factor receptor-3 (VEGFR-3), vascular endothelial growth factor-C (VEGF-C), and Prospero homeobox 1 (Prox1) on postoperative day 4 was significantly higher in the roxadustat group compared with the control group. Conclusions: Roxadustat demonstrated a therapeutic effect in a murine model of hindlimb lymphedema through promotion of lymphangiogenesis through the activation of HIF-1α, VEGF-C, VEGFR-3, and Prox1, suggesting the potential of roxadustat as a therapeutic option in lymphedema.

Characteristic Features of Deep Brain Lymphatic Vessels and Their Regulation by Chronic Stress.

Studies have demonstrated that a functional network of meningeal lymphatic vessels exists in the brain. However, it is unknown whether lymphatic vessels could also extend deep into the brain parenchyma and whether the vessels could be regulated by stressful life events. We used tissue clearing techniques, immunostaining, light-sheet whole-brain imaging, confocal imaging in thick brain sections and flow cytometry to demonstrate the existence of lymphatic vessels deep in the brain parenchyma. Chronic unpredictable mild stress or chronic corticosterone treatment was used to examine the regulation of brain lymphatic vessels by stressful events. Western blotting and coimmunoprecipitation were used to provide mechanistic insights. We demonstrated the existence of lymphatic vessels deep in the brain parenchyma and characterized their features in the cortex, cerebellum, hippocampus, midbrain, and brainstem. Furthermore, we showed that deep brain lymphatic vessels can be regulated by stressful life events. Chronic stress reduced the length and areas of lymphatic vessels in the hippocampus and thalamus but increased the diameter of lymphatic vessels in the amygdala. No changes were observed in prefrontal cortex, lateral habenula, or dorsal raphe nucleus. Chronic corticosterone treatment reduced lymphatic endothelial cell markers in the hippocampus. Mechanistically, chronic stress might reduce hippocampal lymphatic vessels by down-regulating vascular endothelial growth factor C receptors and up-regulating vascular endothelial growth factor C neutralization mechanisms. Our results provide new insights into the characteristic features of deep brain lymphatic vessels, as well as their regulation by stressful life events.

The Peripheral Lymphatic System Is Impaired by the Loss of Neuronal Control Associated with Chronic Spinal Cord Injury

Spinal cord injury (SCI) is associated with venous vascular dysfunction below the level of injury, resulting in dysregulation of tissue fluid homeostasis in afflicted skin. The purpose of this study was to determine whether loss of neuronal control in chronic SCI also affects the skin lymphatic system. Morphology of lymphatics was characterized by immunohistochemistry and lymphatic gene expression profiles determined by DNA microarray analysis. In SCI, skin lymphatic function appeared to be impaired, because the ratio of functionally dilated versus collapsed lymphatic vessels was decreased 10-fold compared with control. Consequently, the average lumen area of lymphatic vessels was almost halved, possibly due to the known impaired connective tissue integrity of SCI skin. In fact, collagenases were found to be overexpressed in SCI skin, and dermal collagen structure was impaired. Molecular profiling also suggested an SCI-specific phenotype of increased connective tissue turnover and decreased lymphatic contractility. The total number of lymphatic vessels in SCI skin, however, was doubled, pointing to enhanced lymphangiogenesis. In conclusion, these data show, for the first time, that lymphatic function and development in human skin are under neuronal control. Because peripheral venous and lymphatic vascular defects are associated with disturbed fluid homeostasis, inappropriate wound healing reactions, and impaired skin immunity, they might contribute to the predisposition of afflicted individuals to pressure ulcer formation and wound healing disorders.

Morphometric study of lymphangiogenesis in different lesions of psoriasis vulgaris with correlation to disease activity.

In the last decades, attention to the role of lymphangiogenesis in psoriasis has been paid. Our study was conducted to evaluate podoplanin-stained lymphatic vessels and the level of lymphangiogenesis in papular psoriatic lesions and psoriatic plaques and ascertain if podoplanin provides any additional prognostic information. Number of lymphatic vessels and total lymphatic vessel area were morphometrically analyzed in podoplanin-stained sections, using anti-D2-40, together with the immunohistochemical study of epidermal Ki-67 in psoriasis vulgaris (n=20) (papules=7 and plaques=13) and control skin specimens (n=20). The number of lymphatic vessels and total lymphatic vessel area were higher in psoriasis cases compared with normal skin (p=0.01, p=0.01 respectively). In psoriatic plaques, the number of lymphatic vessels, total lymphatic vessel area, and epidermal Ki-67 immunoreactivity were higher than in papular lesions (p=0.002, p=0.008, and p=0.01, respectively). Psoriasis vulgaris is found to be a lymphangiogenesis-dependent disease, and the lymphatic vascular network is in remodeling and expanding process. Podoplanin may be implicated in the pathogenesis of psoriasis and could be used as a prognostic biomarker for disease severity and progression.

Dilatation of lymphatic vessels increases liver stiffness on transient elastography irrespective of fibrosis.

Liver stiffness measured using transient elastography (TE) is affected by tissue viscosity. The role of intrahepatic lymphatic fluid in liver stiffness is unclear. The present study aimed to investigate the effects of lymphatic vessel dilatation on liver stiffness. Patients with chronic liver disease (n=116) were enrolled from June 2018 to March 2020. All specimens were acquired by laparoscopic liver biopsy. Biopsy samples were stained with D2-40 for lymphatic vessel quantification based on a five-point scale for each specimen. Independent associations of liver stiffness measured by TE, strain elasticity (liver fibrosis index), and controlled attenuation parameter with fibrosis, lymphatic vessels, alanine aminotransferase, bilirubin, and steatosis were evaluated. Fibrosis, splenic stiffness measurement, and splenic volume were significantly correlated with the area of lymphatic vessels. Fibrosis, lymphatic vessels, and alanine aminotransferase were independent factors significantly associated with liver stiffness measurement (LSM; standardized coefficient [β]=0.375, P<0.001; β=0.342, P<0.001; and β=0.359, P<0.001, respectively). Fibrosis was the only independent factor significantly associated with liver fibrosis index (β=0.360, P<0.001), whereas the fat deposit area was the only independent factor significantly associated with controlled attenuation parameter (β=0.455, P<0.001). The areas under the receiver operating characteristic curves for diagnosing controlled ascites based on LSM, liver fibrosis index, splenic stiffness measurement, collagen proportionate area, and area of lymphatic vessels were 0.94, 0.66, 0.76, 0.64, and 0.79, respectively. Lymphatic vessel dilatation can affect liver stiffness measured using TE. Liver stiffness measurement is a predictive factor for ascites.

Are tumor-associated micro-angiogenesis and lymphangiogenesis considered as the novel prognostic factors for patients with Xp11.2 translocation renal cell carcinoma?

BackgroundTumor micro-angiogenesis and lymphangiogenesis are effective prognostic predictors in many solid malignancies. However, its role on Xp11.2 translocation RCC has not been fully elucidated. Herein, we purposed to explore the correlation between quantitative parameters of tumor-related micro-angiogenesis or lymphangiogenesis and the prognosis of Xp11.2 translocation renal cell carcinoma (Xp11.2 translocation RCC).MethodsTissue samples were obtained from 34 Xp11.2 translocation RCC and 77 clear cell renal cell carcinoma (ccRCC) between January 2007 and December 2018. Micro-angiogenesis was detected using CD34 antibody and quantified with microvessel density (MVD) and microvessel area (MVA), while the lymphangiogenesis in RCC was immunostained with D2–40 antibody and assessed using lymphatic vessel density (LVD) and lymphatic vessel area (LVA). The Kaplan-Meier method of survival analysis was used to estimate prognosis, and both univariate and multivariate analysis was performing using the Cox proportional hazards.ResultsThe MVD and MVA of Xp11.2 translocation RCC in two detected areas (intratumoral and peritumoral area) were not significantly different from that of ccRCC (all P > 0.05). Notably, D2–40-positive lymphatic vessels of Xp11.2 translocation RCC were highly detected in the peritumoral area compared to the intratumoral area. Interestingly, the peritumoral LVD and LVA of Xp11.2 translocation RCC were higher than that of ccRCC (all P < 0.05). Furthermore, both intratumoral MVD or MVA and peritumoral LVD or LVA were significantly associated with pT stage, pN stage, cM stage, AJCC stage, and WHO/ISUP grade (all P < 0.05). Univariate analysis of Cancer-specific survival (CSS) revealed that CSS was substantially longer in patients with low intratumoral MVD or MVA than in patients with high intratumoral MVD or MVA (P = 0.005 and P = 0.001, respectively). Lastly, the Cox proportional hazards model in CSS demonstrated that both intratumoral MVD or MVA and peritumoral LVD or LVA were not independent prognostic parameters (all P > 0.05).ConclusionsThis study outlines that Xp11.2 translocation RCC is a highly vascularized solid RCC, characterized by rich lymph vessels in the peritumoral area. Quantitative parameters of micro-angiogenesis and lymphangiogenesis could not be considered as novel prognostic factors for patients with xp11.2 translocation RCC.

Histopathological evaluation of the effectiveness of oral Eppikajutsuto treatment for lymphatic malformation

BackgroundLymphatic malformation (LM) is a congenital disease caused by lymphatic vessel malformation. Although standard therapies for LMs are sclerotherapy and/or surgical excision, a new therapy using Japanese herbal medicine Eppikajutsuto (TJ-28) has been recently reported as clinically effective. We aimed to experimentally confirm the therapeutic effectiveness of TJ-28 for LMs. MethodsLM lesions were generated in the mesentery and peritoneum of mice by intraperitoneal injection of Freund's incomplete adjuvant. Mice with LMs were treated by gavage or dietary administration of TJ-28 for 2 months. Formalin-fixed paraffin-embedded tissue sections of mesentery and peritoneum tissues were histologically and immunohistochemically examined by focusing on lymph nodes and perinodal lymph vessels. ResultsMultiple Freund's incomplete adjuvant-associated foreign-body granulomas were formed in the mesentery and peritoneum, resulting in congestion of lymph fluid and dilatation of lymph vessels. The numbers and sizes of lymph nodes were not significantly different between TJ-28-treated and control groups. However, the luminal areas of lymphatic vessels were reduced significantly in the TJ-28 treatment group by both gavage and dietary administrations. ConclusionTJ-28 conspicuously reduced congestion of lymph fluid. This is the first histopathological evaluation of LM model mice to study the effectiveness of oral TJ-28 treatment.

Abstract 377: The Role of Impaired Lymphatic Drainage in Cardiac Transplantation

Functional lymphatic drainage inherently modulates cardiac function by maintaining the immune response and tissue-fluid homeostasis. During cardiac transplantation, the lymphatic collecting vessels are severed at the time of heart excision and not surgically reconstructed in the recipient. The consequence resulting from impaired lymphatic drainage in transplanted hearts is unknown. We hypothesize disruption of lymphatic drainage potentiates chronic inflammation by impeding the egress of immune cells and pro-inflammatory cytokines out of the myocardium exacerbating transplant rejection. Methods: Banked human allograft biopsies were utilized to retrospectively evaluate lymphatic differences between patients that did and did not develop chronic transplant rejection from 1 week to 5 years after surgery. Immunofluorescence staining permitted quantification of normalized lymphatic vessel number and area throughout the lifespan of each cardiac allograft (n=24). Autopsy patients with non-cardiac related fatalities served as controls to delineate normal cardiac lymphatic distribution (n=6). Results: Patients without chronic rejection displayed an initial presence of lymphatic vasculature that steadily declined (n=12), while patients with chronic rejection exhibited a delayed increase in lymphatic development (n=12). Conclusions: These data show significant differences in lymphatic area between patients with and without chronic transplant rejection at critical timepoints, suggesting delayed lymphangiogenesis may correlate with rejection. Translational Impact: These preliminary human data support further investigation into lymphatic-modifying therapeutics to prolong the life of cardiac allografts.

Prostaglandin E receptor EP4 stimulates lymphangiogenesis to promote mucosal healing during DSS-induced colitis

In the intestine, the formation of new lymphatic vessels from pre-existing lymphatic vasculature (lymphangiogenesis) is related to the progression of inflammatory bowel disease (IBD). However, it remains unclear whether lymphangiogenesis contributes to mucosal repair after acute colitis. Prostaglandin E receptor EP4 suppresses the development of experimental colitis. In this study, we investigated whether EP4 exerts this effect by contributing to lymphangiogenesis, in turn promoting mucosal tissue repair, following acute colitis. We elicited experimental colitis in male C57/BL6 mice by administering dextran sulphate sodium (DSS) via the drinking water for 5 days, followed by normal water for 9 additional days. From Day 5 through Day 13, the experimental mice received a daily dose of EP4-selective agonist, EP4-selective antagonist, or vehicle. On Day 14, mice treated with vehicle had recovered 95 % of body weight and exhibited moderate increases in disease activity and histological score relative to untreated controls. Compared with vehicle, post-treatment with EP4 antagonist increased signs of colitis, colonic tissue destruction, and CD11b+ cell infiltration, associated with elevated lymphatic vessel density (LVD) and reduced percentage of lymphatic vessel area (LVA%). By contrast, post-treatment with EP4 agonist improved disease activity, suppressed CD11b+ infiltration, and decreased levels of inflammatory cytokines; these changes were associated with upregulation of lymphatic growth factors and lymphangiogenesis, as evidenced by increases in LVA% and lymphatic drainage function. Inhibition of vascular endothelial growth factor receptor 3 (VEGFR3) caused a delay in mucosal repair, accompanied by impaired lymphangiogenesis. These results suggest that EP4 stimulation aids in mucosal repair from DSS-induced acute colitis by promoting lymphangiogenesis.

EP4 signaling facilitates mucosal repair after DSS-induced colitis by enhancement of lymphangiogenesis

Lymphatic development in the intestine is related to inflammatory bowel diseases. Prostaglandin E2 (PGE2)/EP4 prevents from the development of experimental colitis. We previously reported that EP4 facilitates wound healing and wound-associated lymphangiogenesis. In the present study, we examined whether EP4 is involved in tissue repair from colitis by enhancement of lymphangiongenesis. Experimental colitis was induced in male C57/Bl6 mice by the administration of dextran sulphate sodium (DSS) via drinking water for 5 days followed by free water drinking. Mice were received EP4 selective agonist, EP4 selective antagonist, or vehicle from Day 5 through Day 14. At Day 14, mice post-treated with EP4 antagonist were susceptible to signs of colitis, increased colonic tissue destruction and infiltration of macrophages. The increased lymphatic vessel density (LVD) was increased, but percentage of lymphatic vessel area (LVA%) was reduced. These were associated with decreased levels of lymphatic markers and pro-lymphangiogenic factors including VEGF-C and VEGF-D. By contrast, post-treatment with EP4 agonist improved signs of DSS-colitis, suppressed macrophage infiltration and cytokines. This was associated with further enhancement of lymphatic factors and lymphangiogenesis as evidenced by higher LVD and LVA%, and fluorescence intensity in the mesenteric lymph nodes. These results suggest that EP4 activation is helpful for attenuation of DSS-induced colitis by enhancement of drainage function through enlarged lymphatic vessels.

Survival prediction in patients with cutaneous melanoma by tumour lymphangiogenesis

ABSTRACT Objectives: Melanoma induces lymphangiogenesis by secreting lymphangiogenic growth factors. The aim of this study was to examine the role of tumour lymphangiogenesis in survival of patients with cutaneous melanoma. Methods: Immunostaining of one hundred melanoma specimens was done with lymphatic-specific antibody D2-40. The quantification of tumour lymphangiogenesis – lymphatic vessel density (LVD) and lymphatic vessel area (LVA) – was calculated by computer-assisted morphometric analysis. Results: High intratumoural LVD, high peritumoural LVD, male gender, greater tumour thickness and Clark level IV/V were significantly associated with shorter disease-free survival (p= 0.001, p= 0.004, p= 0.004, p= 0.000 and p= 0.008, respectively) and melanoma-specific survival (p= 0.002, p= 0.002, p= 0.001, p= 0.000 and p= 0.017, respectively), while the trunk melanoma site was significantly associated only with shorter disease-free survival (p= 0.033). No significant association of LVA with survival was found. At multivariate analysis, peritumoural LVD [hazard ratio (HR) = 2.143, 95% confidence interval (CI) 1.097–4.189, p= 0.026)] and melanoma thickness (HR = 1.276, 95%CI 1.106–1.473, p= 0.001) were independent predictors of disease-free survival, while intratumoural LVD (HR = 3.446, 95%CI 1.465–8.109, p= 0.005), peritumoural LVD (HR = 2.742, 95%CI 1.313–5.725, p= 0.007) and gender (HR = 2.880, 95%CI 1.304–6.362, p= 0.009) were independent predictors of melanoma-specific survival. Conclusion: Тhis study shows that LVD enables better prediction of survival than melanoma thickness and other clinical-pathological parameters. Intratumoural LVD is the most significant predictor of melanoma-specific survival, while only peritumoural LVD has a significant impact on both, a disease-free survival and a melanoma-specific survival.

Dilated Blood and Lymphatic Microvessels, Angiogenesis, Increased Macrophages, and Adipocyte Hypertrophy in Lipedema Thigh Skin and Fat Tissue.

Background and Aim Lipedema is a common painful SAT disorder characterized by enlargement of fat primarily in the legs of women. Case reports of lipedema tissue samples demonstrate fluid and fibrosis in the interstitial matrix, increased macrophages, and adipocyte hypertrophy. The aims of this project are to investigate blood vasculature, immune cells, and structure of lipedema tissue in a cohort of women. Methods Forty-nine participants, 19 controls and 30 with lipedema, were divided into groups based on body mass index (BMI): Non-Obese (BMI 20 to <30 kg/m2) and Obese (BMI 30 to <40 kg/m2). Histological sections from thigh skin and fat were stained with H&E. Adipocyte area and blood vessel size and number were quantified using ImageJ software. Markers for macrophages (CD68), mast cells (CD117), T cells (CD3), endothelial cells (CD31), blood (SMA), and lymphatic (D2-40 and Lyve-1) vessels were investigated by IHC and IF. Results Non-Obese Lipedema adipocyte area was larger than Non-Obese Controls (p=0.005) and similar to Obese Lipedema and Obese Controls. Macrophage numbers were significantly increased in Non-Obese (p < 0.005) and Obese (p < 0.05) Lipedema skin and fat compared to Control groups. No differences in T lymphocytes or mast cells were observed when comparing Lipedema to Control in both groups. SMA staining revealed increased dermal vessels in Non-Obese Lipedema patients (p < 0.001) compared to Non-Obese Controls. Lyve-1 and D2-40 staining showed a significant increase in lymphatic vessel area but not in number or perimeter in Obese Lipedema participants (p < 0.05) compared to Controls (Obese and Non-Obese). Areas of angiogenesis were found in the fat in 30% of lipedema participants but not controls. Conclusion Hypertrophic adipocytes, increased numbers of macrophages and blood vessels, and dilation of capillaries in thigh tissue of non-obese women with lipedema suggest inflammation, and angiogenesis occurs independent of obesity and demonstrates a role of altered vasculature in the manifestation of the disease.

Immunohistochemical study of CD34 and podoplanin in periodontal disease.

The aim of this study was to evaluate the angiogenesis and lymphangiogenesis in gingival tissue biopsy specimens of individuals with clinically healthy gingiva, chronic gingivitis, and chronic periodontitis (n=30 per clinical condition). Histological sections were stained using hematoxylin and eosin as well as immunohistochemically with hematopoietic progenitor cell antigen CD34 and podoplanin (PDPN) antibodies to evaluate the microvascular count, area, and perimeter of blood and lymphatic vessels, respectively. The results revealed a correlation between the microvascular count of blood and lymphatic vessels (P=0.03; however, in individuals with chronic periodontitis, fewer lymphatic vessels were present than in the clinically healthy gingival tissue (P=0.01), which was not observed in the case of microvascular area and perimeter. Podoplanin labeling was present in the epithelium, and the intensity of labeling was positively correlated to the intensity of the inflammatory infiltrate (P=0.03). In this study, we concluded that an increase in the number of blood and lymphatic vessels was not observed in bouth gingivitis and periodontitis samples. Podoplanin expression is highly associated with an increased inflammatory infiltration suggesting that PDPN might play an additional role in periodontal disease, other than solely as a lymphangiogenesis marker.

Significant increases in the density and number of lymphatic vessels in pleuroparenchymal fibroelastosis.

Some investigators have detected fibrinous exudate or immature organisation in the alveolar spaces prior to the development of subpleural elastofibrosis in patients with pleuroparenchymal fibroelastosis (PPFE). We hypothesised that PPFE progress is associated with an impaired lymphatic drainage system, resulting in the failed resolution of intra-alveolar exudate. The aim of this study is to investigate the pulmonary lymphatic vessels in PPFE, histologically. We retrospectively reviewed our medical records from 1995 to 2017, and selected autopsied or surgically biopsied patients with PPFE (n=18), pulmonary apical cap (n=18), and IPF (n=26). We detected lymphatic endothelial cells by using immunostained specimens, calculating the percentage of lymphatic vessel area in the non-aerated area (lymphatic vessel density) and the number of lymphatic vessels per non-aerated area (per mm2 ) (lymphatic vessel number). These parameters in PPFE were compared with those in apical cap, IPF, and normal lung tissue. The lymphatic vessel density in PPFE patients [2.97%; interquartile range (IQR) 2.61-3.86] was significantly higher than that in normal lung (0.91%; IQR 0.84-1.07), pulmonary apical cap (0.67%; IQR 0.58-0.83), and IPF (0.91%; IQR 0.68-1.25) (P<0.01 in any comparison). The lymphatic vessel number in PPFE was also significantly higher than that in normal lung, pulmonary apical cap, and IPF. Among PPFE patients, the increase in lymphatic vessel density was found to be correlated with the characteristic physiology of PPFE, such as a flattened chest cage on computed tomography and high residual volume/total lung capacity ratio on spirometry. Significant increase in the density and number of lymphatic vessels is a supportive characteristic that enables the differentiation of PPFE from IPF and apical cap.

Lymphangiogenesis Facilitates Initial Lymph Formation and Enhances the Dendritic Cell Mobilizing Chemokine CCL21 Without Affecting Migration.

Lymphatic vessels play an important role in body fluid, as well as immune system homeostasis. Although the role of malfunctioning or missing lymphatics has been studied extensively, less is known on the functional consequences of a chronically expanded lymphatic network or lymphangiogenesis. To this end, we used K14-VEGF-C (keratin-14 vascular endothelial growth factor-C) transgenic mice overexpressing the vascular endothelial growth factor C in skin and investigated the responses to inflammatory and fluid volume challenges. We also recorded interstitial fluid pressure, a major determinant of lymph flow. Transgenic mice had a strongly enhanced lymph vessel area in skin. Acute inflammation induced by lipopolysaccharide and chronic inflammation by delayed-type hypersensitivity both resulted in increased interstitial fluid pressure and reduced lymph flow, both to the same extent in wild-type and transgenic mice. Hyperplastic lymphatic vessels, however, demonstrated enhanced transport capacity after local fluid overload not induced by inflammation. In this situation, interstitial fluid pressure was increased to a similar extent in the 2 strains, thus, suggesting that the enhanced lymph vessel area facilitated initial lymph formation. The increased lymph vessel area resulted in an enhanced production of the chemoattractant CCL21 that, however, did not result in augmented dendritic cell migration after induction of local skin inflammation by fluorescein isothiocyanate. An expanded lymphatic network is capable of enhanced chemoattractant production, and lymphangiogenesis will facilitate initial lymph formation favoring increased clearance of fluid in situations of augmented fluid filtration.

Neoadjuvant hormonal therapy for low-risk prostate cancer induces biochemical recurrence after radical prostatectomy via increased lymphangiogenesis-related parameters.

BackgroundThe effects of neoadjuvant hormonal therapy (NHT) on pathological features and lymphangiogenesis in patients with prostate cancer (PCa) for each pre‐operative risk classification are unclear.MethodsTo clarify the anti‐cancer effects of NHT, we investigated 153 patients (non‐NHT group = 80 and NHT group = 73) who underwent radical prostatectomy (RP) in Nagasaki University Hospital. Lymph vessel density and area (evaluated by D2‐40‐positive vessels), vascular endothelial growth factor (VEGF)‐C and VEGF‐D expressions, and biochemical recurrence (BCR)‐free survival were compared between these two groups for each D'Amico risk classification (low = 33, intermediate = 58, high = 62 patients).ResultsIn low‐risk PCa patients, the risks of lymph vessel invasion and BCR were significantly higher in the NHT group than in the non‐NHT group (P = 0.040 and 0.022, respectively). Such significant difference was not seen in the intermediate‐ or high‐risk PCa groups. Lymph vessel density of the peri‐tumoral and intra‐tumoral areas and the lymph vessel area were significantly higher (P < 0.001) in the NHT group than in the non‐NHT group in low‐risk PCa. In regard to the expression of VEGF‐C or VEGF‐D, significant difference was not detected in low‐risk PCa.ConclusionsNHT stimulated cancer cell progression and BCR via up‐regulation of lymphangiogenesis‐related parameters in patients with low‐risk PCa. Although VEGF‐C and VEGF‐D expressions were not changed by NHT, lymph vessel density and area were increased in low‐risk PCa patients. We suggest that NHT for patients with low‐risk PCa may have a high risk for BCR after RP.