Distinct characteristics of circulating vascular endothelial growth factor-a and C levels in human subjects

Prognostic Significance of Plasma VEGFA and VEGFR2 in Acute Ischemic Stroke-a Prospective Cohort Study

Enhancement of vascular remodeling in affected brain tissue is a novel therapy for acute ischemic stroke (AIS). However, conclusions regarding angiogenesis after AIS remain ambiguous. Vascular endothelial growth factor A (VEGFA) and VEGF receptor 2 (VEGFR2) are potent regulators of angiogenesis and vascular permeability. We aimed to investigate the association between VEGFA/VEGFR2 expression in the acute stage of stroke and prognosis of patients with AIS. We enrolled 120 patients with AIS within 24 h of stroke onset and 26 healthy controls. Plasma levels of VEGFA and VEGFR2 were measured by enzyme-linked immunosorbent assay (ELISA). The primary endpoint was an unfavorable outcome defined as a modified Rankin Scale (mRS) score > 2 at 3 months after AIS. Univariate and multivariate logistic regression analyses were used to identify risk factors affecting prognosis. Plasma VEGFA and VEGFR2 were significantly higher in patients with AIS than in health controls, and also significantly higher in patients with unfavorable than those with favorable outcomes. Moreover, both VEGFA and VEGFR2 showed a significantly positive correlation with mRS at 3 months. Univariate and multivariate analyses showed VEGFA and VEGFR2 remained associated with unfavorable outcomes, and adding VEGFA and VEGFR2 to the clinical model significantly improved risk reclassification (continuous net reclassification improvement, 105.71%; integrated discrimination improvement, 23.45%). The new risk model curve exhibited a good fit with an area under the receiver operating characteristic curve (ROC) curve of 0.9166 (0.8658-0.9674). Plasma VEGFA and VEGFR2 are potential markers for predicting prognosis; thus these two plasma biomarkers may improve risk stratification in patients with AIS.

Association of vascular endothelial growth factor-C, plasma angiotensinogen and left ventricular hypertrophy in patients with hemodialysis

INTRODUCTION

This study aims to examine the relationship between fluid overload, Vascular Endothelial Growth Factor C (VEGF-C), plasma Angiotensinogen (pAGT), and echocardiography findings in hemodialysis patients.

METHODS

This was a single-center, cross-sectional study. Patients were divided into two groups according to mid-week inter-dialytic weight gain (mIDWG): (1) mIDWG ≤3% and (2) mIDW >3%.

RESULTS

A total of 55 patients were enrolled in this study. While the mean pAGT and left ventricular mass index were significantly higher in patients with mIDWG >3% compared to patients with mIDWG ≤3%, VEGF-C was similar between groups. pAGT ≥76.8 mcg/L, VEGF-C ≤175.5 pg/ML, and pAGT /VEGF-C ≥0.45 were significant cut-offs for the prediction of left ventricular hypertrophy(LVH). Univariate logistic regression analysis revealed that these cut-off values were significantly associated with LVH.

CONCLUSION

Renin-angiotensin-aldosterone system activation may persist in hemodialysis patients with excessive IDWG. Additionally, pAGT and VEGF-C could be risk factors for the development of LVH.

Genome-wide association study and polygenic score assessment of insulin resistance

Insulin resistance (IR) and beta cell dysfunction are the major drivers of type 2 diabetes (T2D). Genome-Wide Association Studies (GWAS) on IR have been predominantly conducted in European populations, while Middle Eastern populations remain largely underrepresented. We conducted a GWAS on the indices of IR (HOMA2-IR) and beta cell function (HOMA2-%B) in 6,217 non-diabetic individuals from the Qatar Biobank (QBB; Discovery cohort; n = 2170, Replication cohort; n = 4047) with and without body mass index (BMI) adjustment. We also developed polygenic scores (PGS) for HOMA2-IR and compared their performance with a previously derived PGS for HOMA-IR (PGS003470). We replicated 11 loci that have been previously associated with HOMA-IR and 24 loci that have been associated with HOMA-%B, at nominal statistical significance. We also identified a novel locus associated with beta cell function near VEGFC gene, tagged by rs61552983 (P = 4.38 × 10-8). Moreover, our best performing PGS (Q-PGS4; Adj R2 = 0.233 ± 0.014; P = 1.55 x 10-3) performed better than PGS003470 (Adj R2 = 0.194 ± 0.014; P = 5.45 x 10-2) in predicting HOMA2-IR in our dataset. This is the first GWAS on HOMA2 and the first GWAS conducted in the Middle East focusing on IR and beta cell function. Herein, we report a novel locus in VEGFC that is implicated in beta cell dysfunction. Inclusion of under-represented populations in GWAS has potentials to provide important insights into the genetic architecture of IR and beta cell function.

Dysregulation of Lymphatic Endothelial VEGFR3 Signaling in Disease

Vascular endothelial growth factor (VEGF) receptor 3 (VEGFR3), a receptor tyrosine kinase encoded by the FLT4 gene, plays a significant role in the morphogenesis and maintenance of lymphatic vessels. Under both normal and pathologic conditions, VEGF-C and VEGF-D bind VEGFR3 on the surface of lymphatic endothelial cells (LECs) and induce lymphatic proliferation, migration, and survival by activating intracellular PI3K-Akt and MAPK-ERK signaling pathways. Impaired lymphatic function and VEGFR3 signaling has been linked with a myriad of commonly encountered clinical conditions. This review provides a brief overview of intracellular VEGFR3 signaling in LECs and explores examples of dysregulated VEGFR3 signaling in various disease states, including (1) lymphedema, (2) tumor growth and metastasis, (3) obesity and metabolic syndrome, (4) organ transplant rejection, and (5) autoimmune disorders. A more complete understanding of the molecular mechanisms underlying the lymphatic pathology of each disease will allow for the development of novel strategies to treat these chronic and often debilitating illnesses.

Colon tumor CD31 expression is associated with higher disease-free survival in patients with metabolic syndrome

Metabolic syndrome (MS) is recognized as a risk factor for colon cancer (CC). However, how does the interplay between metabolic dysfunction caused by MS and its individual components affect CC microenvironment and prognosis remains unexplored. Angiogenesis and lymphangiogenesis are fundamental processes for tumor progression and dissemination, ensuring oxygen and nutrient delivery and supporting one of the most important pathways of tumor dissemination, contributing to metastasis. Thus, our aim was to evaluate whether the expression of molecular biomarkers involved in angiogenic and lymphangiogenic processes influenced CC clinicopathological features and prognosis in patients with MS. Clinical and pathological data of 300 patients submitted to CC surgical resection at a single tertiary hospital were retrospectively retrieved from hospital records. Tumor tissue microarrays of archived paraffin-embedded blocks were used to assess CD31, VEGF-A and D2-40 tissue expression by immunohistochemistry. The percentage of stained area was quantified by computerized morphometric analysis. No association between tissue expression of angiogenesis and lymphangiogenesis biomarkers and tumor clinical and pathological characteristics was found. However, in subgroup analysis of patients with MS, dysglycemia was associated with lower D2-40 expression (p = 0.007) and high waist-circumference was associated with higher D2-40 (p = 0.0029) and VEGF-A expression (p = 0.026). In an adjusted Cox proportional hazard model CD31 expression was significantly associated with greater disease-free survival (HR=0.62; 95% CI: 0.41-0.95, p = 0.028). No association was found between D2-40 and VEGF-A expression and CC prognosis. Our data reinforces previous reports that suggest the potential use of CD31 as a CC prognostic biomarker. Additionally, our data further supports the evidence for an interplay between metabolic dysfunction, tumor microenvironment, and vascularization pathways.

The role of lacteal integrity and junction transformation in obesity: A promising therapeutic target?

Lacteals are the central lymphatic vessels in the villi of the small intestine and perform nutrient absorption, especially dietary lipids, and the transportation of antigen and antigen-presenting cells. Remodeling, proliferation, and cell-cell junctions of lymphatic endothelial cells (LECs) in lacteals are the basis of the maintenance of lacteal integrity and dietary lipid absorption. Normal lipid absorption in the diet depends on sound lacteal development and proliferation, especially integrity maintenance, namely, maintaining the appropriate proportion of button-like and zipper-like junctions. Maintaining the integrity and transforming button-to-zipper junctions in lacteals are strongly connected with obesity, which could be regulated by intestinal flora and molecular signalings, such as vascular endothelial growth factor C-vascular endothelial growth receptor 3 (VEGFC-VEGFR3) signaling, Hippo signaling, Notch signaling, angiopoietin-TIE signaling, VEGF-A/VEGFR2 signaling, and PROX1. This manuscript reviews the molecular mechanism of development, integrity maintenance, and junction transformation in lacteal related to obesity.

Adipose Tissue and Biological Factors. Possible Link between Lymphatic System Dysfunction and Obesity

The World Health Organization (WHO) has recognised obesity as one of the top ten threats to human health. Obesity is not only a state of abnormally increased adipose tissue in the body, but also of an increased release of biologically active metabolites. Moreover, obesity predisposes the development of metabolic syndrome and increases the incidence of type 2 diabetes (T2DM), increases the risk of developing insulin resistance, atherosclerosis, ischemic heart disease, polycystic ovary syndrome, hypertension and cancer. The lymphatic system is a one-directional network of thin-walled capillaries and larger vessels covered by a continuous layer of endothelial cells that provides a unidirectional conduit to return filtered arterial and tissue metabolites towards the venous circulation. Recent studies have shown that obesity can markedly impair lymphatic function. Conversely, dysfunction in the lymphatic system may also be involved in the pathogenesis of obesity. This review highlights the important findings regarding obesity related to lymphatic system dysfunction, including clinical implications and experimental studies. Moreover, we present the role of biological factors in the pathophysiology of the lymphatic system and we propose the possibility of a therapy supporting the function of the lymphatic system in the course of obesity.

The Role of the VEGF Family in Coronary Heart Disease

The vascular endothelial growth factor (VEGF) family, the regulator of blood and lymphatic vessels, is mostly investigated in the tumor and ophthalmic field. However, the functions it enjoys can also interfere with the development of atherosclerosis (AS) and further diseases like coronary heart disease (CHD). The source, regulating mechanisms including upregulation and downregulation, target cells/tissues, and known functions about VEGF-A, VEGF-B, VEGF-C, and VEGF-D are covered in the review. VEGF-A can regulate angiogenesis, vascular permeability, and inflammation by binding with VEGFR-1 and VEGFR-2. VEGF-B can regulate angiogenesis, redox, and apoptosis by binding with VEGFR-1. VEGF-C can regulate inflammation, lymphangiogenesis, angiogenesis, apoptosis, and fibrogenesis by binding with VEGFR-2 and VEGFR-3. VEGF-D can regulate lymphangiogenesis, angiogenesis, fibrogenesis, and apoptosis by binding with VEGFR-2 and VEGFR-3. These functions present great potential of applying the VEGF family for treating CHD. For instance, angiogenesis can compensate for hypoxia and ischemia by growing novel blood vessels. Lymphangiogenesis can degrade inflammation by providing exits for accumulated inflammatory cytokines. Anti-apoptosis can protect myocardium from impairment after myocardial infarction (MI). Fibrogenesis can promote myocardial fibrosis after MI to benefit cardiac recovery. In addition, all these factors have been confirmed to keep a link with lipid metabolism, the research about which is still in the early stage and exact mechanisms are relatively obscure. Because few reviews have been published about the summarized role of the VEGF family for treating CHD, the aim of this review article is to present an overview of the available evidence supporting it and give hints for further research.

Soluble vascular endothelial growth factor receptor 2 and prognosis in patients with chronic heart failure

Aims

Endothelial cell vascular endothelial growth factor receptor 2 (VEGFR‐2) plays a pivotal role in angiogenesis, which induces physiological cardiomyocyte hypertrophy via paracrine signalling between endothelial cells and cardiomyocytes. We investigated whether a decrease in circulating soluble VEGFR‐2 (sVEGFR‐2) levels is associated with poor prognosis in patients with chronic heart failure (HF).

Methods and results

We performed a multicentre prospective cohort study of 1024 consecutive patients with HF, who were admitted to hospitals due to acute decompensated HF and were stabilized after initial management. Serum levels of sVEGFR‐2 were measured at discharge. Patients were followed up over 2 years. The outcomes were cardiovascular death, all‐cause death, major adverse cardiovascular events (MACE) defined as a composite of cardiovascular death and HF hospitalization, and HF hospitalization. The mean age of the patients was 75.5 (standard deviation, 12.6) years, and 57% were male. Patients with lower sVEGFR‐2 levels were older and more likely to be female, and had greater proportions of atrial fibrillation and anaemia, and lower proportions of diabetes, dyslipidaemia, and HF with reduced ejection fraction (<40%). During the follow‐up, 113 cardiovascular deaths, 211 all‐cause deaths, 350 MACE, and 309 HF hospitalizations occurred. After adjustment for potential clinical confounders and established biomarkers [N‐terminal B‐type natriuretic peptide (NT‐proBNP), high‐sensitivity cardiac troponin I, and high‐sensitivity C‐reactive protein], a low sVEGFR‐2 level below the 25th percentile was significantly associated with cardiovascular death [hazard ratio (HR), 1.79; 95% confidence interval (CI), 1.16–2.74] and all‐cause death (HR, 1.43; 95% CI, 1.04–1.94), but not with MACE (HR, 1.11; 95% CI, 0.86–1.43) or HF hospitalization (HR, 1.03; 95% CI, 0.78–1.35). The stratified analyses revealed that a low sVEGFR‐2 level below the 25th percentile was significantly associated with cardiovascular death (HR, 1.76; 95% CI, 1.07–2.85) and all‐cause death (HR, 1.49; 95% CI, 1.03–2.15) in the high‐NT‐proBNP group (above the median), but not in the low‐NT‐proBNP group. Notably, the patients with high‐NT‐proBNP and low‐sVEGFR‐2 (below the 25th percentile) had a 2.96‐fold higher risk (95% CI, 1.56–5.85) for cardiovascular death and a 2.40‐fold higher risk (95% CI, 1.52–3.83) for all‐cause death compared with those with low‐NT‐proBNP and high‐sVEGFR‐2.

Conclusions

A low sVEGFR‐2 value was independently associated with cardiovascular death and all‐cause death in patients with chronic HF. These associations were pronounced in those with high NT‐proBNP levels.

Analysis of probable lipotoxic damage and myocardial fibrosis in epicardial obesity

Myocardial fibrosis is considered a key pathological process in the development of cardiovascular diseases. In epicardial obesity (EO), the main cause of fibrosis development is lipotoxic myocardial damage. It is important to detect myocardial fibrosis at an early stage, using non-invasive diagnostic methods. According to the results of echocardiography (ECG), 110 men with general obesity were divided into the following two groups: Group I with epicardial fat thickness (tEAT) ≥ 7 mm (n = 70) and Group II with tEAT < 7 mm (n = 40) without diastolic dysfunction. The levels of metabolic factors, pro-inflammatory cytokines, adipokines, and free fatty acids (FFA), profibrotic markers were determined in both groups. In Group I, the level of interleukin (IL)-6, C-reactive protein, and tumor necrosis factor (TNF)-α increased and that of leptin and adiponectin decreased compared with those in Group II. There was an increase in the level of all studied profibrotic factors in Group I. The level of TNF-α and IL-6 showed a positive correlation with the level of leptin and FFA and a negative correlation with the level of adiponectin. We also observed a relationship between the level of collagen, transforming growth factor (TGF)-β, and metalloproteinase (MMP)-3 and EO. Our results showed that confirmed EO correlates with not only disadipocytosis and increased levels of pro-inflammatory cytokines, but also increased levels of profibrotic factors. This suggests that the studied markers of fibrosis may be used to determine preclinical cardiac fibrosis with lipotoxic myocardial damage in patients with EO.

On-line hemodiafiltration modulates atherosclerosis signaling in peripheral lymphomonocytes of hemodialysis patients

Background

Hemodialysis patients present a dramatic increase in cardiovascular morbidity/mortality. Circulating immune cells, activated by both uremic milieu and dialysis, play a key role in the pathogenesis of dialysis-related vascular disease. The aim of our study was to identify, through a high-throughput approach, differences in gene expression profiles in the peripheral blood mononuclear cells (PBMCs) of patients treated with on-line hemodiafiltration and bicarbonate hemodialysis.

Methods

The transcriptomic profile was investigated in PBMCs isolated from eight patients on on-line hemodiafiltration and eight patients on bicarbonate hemodialysis by microarray analysis. The results were evaluated by statistical and functional pathway analysis and validated by real time PCR (qPCR) in an independent cohort of patients (on-line hemodiafiltration N = 20, bicarbonate hemodialysis n = 20).

Results

Eight hundred and forty-seven genes were differentially expressed in patients treated with  on-line hemodiafiltration and bicarbonate hemodialysis. Thirty-seven functional gene networks were identified and atherosclerosis signaling was the top canonical pathway regulated by on-line hemodiafiltration. Among the genes of this pathway, on-line hemodiafiltration was associated with a reduced expression of Platelet-derived growth factor A chain (PDGF A), Clusterin, Monoamine Oxidase A, Interleukin-6 (IL-6) and Vascular Endothelial Growth Factor C (VEGF-)C and with an increase of Apolipoprotein E. qPCR confirmed the microarray results. Platelet derived growth factor AA (PDGF-AA), IL-6 and VEGF-C serum levels were significantly lower in the on-line hemodiafiltration group. Finally, 10 patients previously on bicarbonate hemodialysis  were switched to on-line hemodiafiltration and PBMCs were harvested after 6 months. The qPCR results from this perspective group confirmed the modulation of atherosclerotic genes observed in the cross-sectional analysis.

Conclusions

Our data suggest that type of dialysis (on-line hemodiafiltration versus bicarbonate hemodialysis) may modulate the expression of several genes involved in the pathogenesis of atherosclerotic disease.

A Comprehensive miRNome Analysis of Macrophages Isolated from db/db Mice and Selected miRNAs Involved in Metabolic Syndrome-Associated Cardiac Remodeling

Cardiac macrophages are known from various activities, therefore we presume that microRNAs (miRNAs) produced or released by macrophages in cardiac tissue have impact on myocardial remodeling in individuals with metabolic syndrome (MetS). We aim to assess the cardiac macrophage miRNA profile by selecting those miRNA molecules that potentially exhibit regulatory functions in MetS-related cardiac remodeling. Cardiac tissue macrophages from control and db/db mice (an animal model of MetS) were counted and sorted with flow cytometry, which yielded two populations: CD45+CD11b+CD64+Ly6Chi and CD45+CD11b+CD64+Ly6Clow. Total RNA was then isolated, and miRNA expression profiles were evaluated with Next Generation Sequencing. We successfully sequenced 1400 miRNAs in both macrophage populations: CD45+CD11b+CD64+Ly6Chi and CD45+CD11b+CD64+Ly6Clow. Among the 1400 miRNAs, about 150 showed different expression levels in control and db/db mice and between these two subpopulations. At least 15 miRNAs are possibly associated with MetS pathology in cardiac tissue due to direct or indirect regulation of the expression of miRNAs for proteins involved in angiogenesis, fibrosis, or inflammation. In this paper, for the first time we describe the miRNA transcription profile in two distinct macrophage populations in MetS-affected cardiac tissue. Although the results are preliminary, the presented data provide a foundation for further studies on intercellular cross-talk/molecular mechanism(s) involved in the regulation of MetS-related cardiac remodeling.

Efficient aortic lymphatic drainage is necessary for atherosclerosis regression induced by ezetimibe

A functional lymphatic vasculature is essential for tissue fluid homeostasis, immunity, and lipid clearance. Although atherosclerosis has been linked to adventitial lymphangiogenesis, the functionality of aortic lymphatic vessels draining the diseased aorta has never been assessed and the role of lymphatic drainage in atherogenesis is not well understood. We develop a method to measure aortic lymphatic transport of macromolecules and show that it is impaired during atherosclerosis progression, whereas it is ameliorated during lesion regression induced by ezetimibe. Disruption of aortic lymph flow by lymphatic ligation promotes adventitial inflammation and development of atherosclerotic plaque in hypercholesterolemic mice and inhibits ezetimibe-induced atherosclerosis regression. Thus, progression of atherosclerotic plaques may result not only from increased entry of atherogenic factors into the arterial wall but also from reduced lymphatic clearance of these factors as a result of aortic lymph stasis. Our findings suggest that promoting lymphatic drainage might be effective for treating atherosclerosis.

[Angiogenesis system, as a part of endothelial dysfunction in patients with diabetes mellitus type 2: relationship with obesity]

AIM

To investigate parameters of angiogenesis system in patients with diabetes mellitus and their relationship with obesity.

MATERIALS AND METHODS

104 patients with diabetes mellitus type 2 were included in the study. Patients were divided in 2 groups: Obesity+ (body mass index30 kg/m2;n=63) and Obesity- (body mass index 30 kg/m2;n=41). In all patients was performed clinico-diagnostical examination. mRNA expression levels of vascular endothelial growth factor (VEGF), its receptors flt-1 (fms-like tyrosine kinase 1), KDR (human kinase insert domain receptor) were determined in blood mononuclear cells.

RESULTS

There were no statistically significant differences in investigated parameters between study groups. mRNA expression level of VEGF was slightly lower in men compared to women: 0.19 (0.14; 0.32)vs0.28 (0.12; 0.4) respectively,р=0.2236. MRNA expression level of flt-1 was lower in men compared to women: 0.14 (0.04; 0.3)vs0.25 (0.12; 0.38),р=0.0321 (statistically significant). We found statistically significant correlations of mRNA expression level of VEGF with mRNA expression level of flt-1 and KDR. Also we found strong positive correlations of BMI and mRNA expression levels VEGF, flt-1, KDR (r=0.86107,r=0.86125,r=0.86112, respectively,p0.001).

CONCLUSION

Results of the study displayed relationship of obesity and angiogenesis system condition in patients with diabetes mellitus type 2. Further investigations are perspective for the future as a way to new therapeutical approach of obesity and its complications treatment.

[Extracellular matrix of the heart and its changes in myocardial fibrosis]

Neurohumoral changes have recently attracted much attention as a part of the pathogenesis of heart failure. Activation of neurohumoral factors triggers processes resulting in changes of extracellular matrix composition and, thus, development of myocardial fibrosis. This article addresses a number of factors that directly contribute to the development of myocardial fibrosis.

Clinical value of TV-CDS combined with serum tumor markers in diagnosis of ovarian cancer

Clinical application value was investigated of transvaginal color Doppler ultrasound (TV-CDS) combined with serum tumor markers carbohydrate antigen 125 (CA125), vascular endothelial growth factor (VEGF) and osteopontin (OPN) in the diagnosis of ovarian cancer (OC). One hundred and six patients with OC [malignant tumor group (MTG)] and fifty patients with benign ovarian diseases [benign control group (BCG)] were selected. Both groups of patients underwent TV-CDS examination. The lesion morphology and internal structure were observed, and the tumor blood flow signal, resistance index (RI) and pulsability index (PI) under ultrasound were determined. Serum CA125 was detected by electrochemiluminescence, and VEGF and OPN levels were detected by enzyme-linked immunosorbent assay. The incidence of irregular lesion morphology, unclear boundary, uneven internal echo, microcalcification and side-acoustic images in OC group (OCG) was significantly higher than that in BCG (P<0.01). As for blood flow grading, most patients in the MTG were in grade II and III, while most patients in the BCG were in grade 0. Compared with BCG, the flow RI and PI in the OCG were significantly reduced (P<0.01). The levels of serum CA125, VEGF and OPN in OCG were significantly higher than those in BCG. The expression levels of serum CA125, VEGF and OPN in OC patients with clinical high stage (stage III and IV), poorly differentiated, ascites, recurrence and metastasis were significantly higher than those in patients with clinical low stage (stage I and II), well differentiated, no ascites and no recurrence and metastasis (P<0.05). With the disappearance of the tumor or the decrease of tumor load, the serum marker levels after treatment were significantly lower than that before treatment (P<0.05). The sensitivity and accuracy of the combined examination in the diagnosis of OC were obviously improved compared with the single and partial combined examinations (P<0.05). In conclusion, combined examination can significantly improve the sensitivity and accuracy of OC, which is conducive to early diagnosis and clinical intervention of OC.

The Role of Lymphatic Vascular Function in Metabolic Disorders

In addition to its roles in the maintenance of interstitial fluid homeostasis and immunosurveillance, the lymphatic system has a critical role in regulating transport of dietary lipids to the blood circulation. Recent work within the past two decades has identified an important relationship between lymphatic dysfunction and patients with metabolic disorders, such as obesity and type 2 diabetes, in part characterized by abnormal lipid metabolism and transport. Utilization of several genetic mouse models, as well as non-genetic models of diet-induced obesity and metabolic syndrome, has demonstrated that abnormal lymphangiogenesis and poor collecting vessel function, characterized by impaired contractile ability and perturbed barrier integrity, underlie lymphatic dysfunction relating to obesity, diabetes, and metabolic syndrome. Despite the progress made by these models, the contribution of the lymphatic system to metabolic disorders remains understudied and new insights into molecular signaling mechanisms involved are continuously developing. Here, we review the current knowledge related to molecular mechanisms resulting in impaired lymphatic function within the context of obesity and diabetes. We discuss the role of inflammation, transcription factor signaling, vascular endothelial growth factor-mediated signaling, and nitric oxide signaling contributing to impaired lymphangiogenesis and perturbed lymphatic endothelial cell barrier integrity, valve function, and contractile ability in collecting vessels as well as their viability as therapeutic targets to correct lymphatic dysfunction and improve metabolic syndromes.

The circulating vascular endothelial growth factor is only marginally associated with an increased risk for atherosclerosis

BACKGROUND

Vascular endothelial growth factor-A (VEGF-A) is a protein that plays a role in the formation and function of blood vessels, promotes increased vascular permeability or migration of monocytes through endothelial layers. We have tested the hypothesis that plasma levels of VEGF-A may be associated with biochemical and radiological parameters as a marker of cardiovascular risk in Caucasian patients with early-onset CAD.

METHODS

The study group included 100 patients: 75 men not older than 50 years and 25 women not older than 55 years at the moment of CAD diagnosis. The control group (patients without CAD) comprised 50 healthy cases. ELISA test was used to measure plasma concentrations of VEGF. Doppler ultrasound of carotid and peripheral arteries was carried out in each patient. Serum glucose, complete lipid profile, ApoA1, ApoB, Lp(a) and blood count were measured in each case.

RESULTS

Only very weak correlations of plasma VEGF levels with biochemical cardiovascular risk factors in the CAD subjects have been demonstrated. In the study group, VEGF concentration was significantly positively correlated with the same blood parameters as white blood cells, platelets, plateletcrit, apolipoprotein B, total and LDL cholesterol fraction. The plaque of common carotid arteries and bifurcation was present in 39% of CAD patients, however, there was no significant association between VEGF plasma concentration and any measured parameters in Doppler ultrasound of carotid and peripheral arteries.

CONCLUSIONS

The circulating VEGF is only marginally associated with an increased risk for atherosclerosis.

Distinct Characteristics of VEGF-D and VEGF-C to Predict Mortality in Patients With Suspected or Known Coronary Artery Disease

Background

VEGF‐D (vascular endothelial growth factor D) and VEGF‐C are secreted glycoproteins that can induce lymphangiogenesis and angiogenesis. They exhibit structural homology but have differential receptor binding and regulatory mechanisms. We recently demonstrated that the serum VEGF‐C level is inversely and independently associated with all‐cause mortality in patients with suspected or known coronary artery disease. We investigated whether VEGF‐D had distinct relationships with mortality and cardiovascular events in those patients.

Methods and Results

We performed a multicenter, prospective cohort study of 2418 patients with suspected or known coronary artery disease undergoing elective coronary angiography. The serum level of VEGF‐D was measured. The primary outcome was all‐cause death. The secondary outcomes were cardiovascular death and major adverse cardiovascular events defined as a composite of cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke. During the 3‐year follow‐up, 254 patients died from any cause, 88 died from cardiovascular disease, and 165 developed major adverse cardiovascular events. After adjustment for possible clinical confounders, cardiovascular biomarkers (N‐terminal pro‐B‐type natriuretic peptide, cardiac troponin‐I, and high‐sensitivity C‐reactive protein), and VEGF‐C, the VEGF‐D level was significantly associated with all‐cause death and cardiovascular death but not with major adverse cardiovascular events.. Moreover, the addition of VEGF‐D, either alone or in combination with VEGF‐C, to the model with possible clinical confounders and cardiovascular biomarkers significantly improved the prediction of all‐cause death but not that of cardiovascular death or major adverse cardiovascular events. Consistent results were observed within patients over 75 years old.

Conclusions

In patients with suspected or known coronary artery disease undergoing elective coronary angiography, an elevated VEGF‐D value seems to independently predict all‐cause mortality.

Lymphatic Vasculature in Energy Homeostasis and Obesity

Obesity is a leading cause of cardiovascular diseases and cancer. Body mass is regulated by the balance between energy uptake and energy expenditure. The etiology of obesity is determined by multiple factors including genetics, nutrient absorption, and inflammation. Lymphatic vasculature is starting to be appreciated as a critical modulator of metabolism and obesity. The primary function of lymphatic vasculature is to maintain interstitial fluid homeostasis. Lymphatic vessels absorb fluids that extravasate from blood vessels and return them to blood circulation. In addition, lymphatic vessels absorb digested lipids from the intestine and regulate inflammation. Hence, lymphatic vessels could be an exciting target for treating obesity. In this article, we will review our current understanding regarding the relationship between lymphatic vasculature and obesity, and highlight some open questions.

VEGF-C and Mortality in Patients With Suspected or Known Coronary Artery Disease

Background

The lymphatic system has been suggested to play an important role in cholesterol metabolism and cardiovascular disease. However, the relationships of vascular endothelial growth factor‐C (VEGF‐C), a central player in lymphangiogenesis, with mortality and cardiovascular events in patients with suspected or known coronary artery disease are unknown.

Methods and Results

We performed a multicenter, prospective cohort study of 2418 patients with suspected or known coronary artery disease undergoing elective coronary angiography. The primary predictor was serum levels of VEGF‐C. The primary outcome was all‐cause death. The secondary outcomes were cardiovascular death, and major adverse cardiovascular events defined as a composite of cardiovascular death, non‐fatal myocardial infarction, and non‐fatal stroke. During the 3‐year follow‐up, 254 patients died from any cause, 88 died from cardiovascular disease, and 165 developed major adverse cardiovascular events. After adjustment for established risk factors, VEGF‐C levels were significantly and inversely associated with all‐cause death (hazard ratio for 1‐SD increase, 0.69; 95% confidence interval, 0.60–0.80) and cardiovascular death (hazard ratio, 0.67; 95% confidence interval, 0.53–0.87), but not with major adverse cardiovascular events (hazard ratio, 0.85; 95% confidence interval, 0.72–1.01). Even after incorporation of N‐terminal pro‐brain natriuretic peptide, contemporary sensitive cardiac troponin‐I, and high‐sensitivity C‐reactive protein into a model with established risk factors, the addition of VEGF‐C levels further improved the prediction of all‐cause death, but not that of cardiovascular death or major adverse cardiovascular events. Consistent results were observed within 1717 patients with suspected coronary artery disease.

Conclusions

In patients with suspected or known coronary artery disease, a low VEGF‐C value may independently predict all‐cause mortality.

Prediction of VEGF-C as a Key Target of Pure Total Flavonoids From Citrus Against NAFLD in Mice via Network Pharmacology

Pure total flavonoids from Citrus (PTFC) effectively reduce the symptoms of non-alcoholic fatty liver disease (NAFLD). Our previous microarray analysis uncovered the alterations of important signaling pathways in the treatment of NAFLD with PTFC. However, the underlying core genes that might be targeted by PTFC, which play important roles in the progression of NALFD are yet to be identified. In this study, we predicted the vascular endothelial growth factor-C (VEGF-C) as potential key molecular target of PTFC against NAFLD via network pharmacology analysis. The network pharmacology approach presented here provided important clues for understanding the mechanisms of PTFC treatment in the development of NAFLD.

Impact of Lipotoxicity on Tissue "Cross Talk" and Metabolic Regulation

Obesity-associated comorbidities include non-alcoholic fatty liver disease, Type 2 diabetes, and cardiovascular disease. These diseases are associated with accumulation of lipids in non-adipose tissues, which can impact many intracellular cellular signaling pathways and functions that have been broadly defined as "lipotoxic." This review moves beyond understanding intracellular lipotoxic outcomes and outlines the consequences of lipotoxicity on protein secretion and inter-tissue "cross talk," and the impact this exerts on systemic metabolism.

Effect of resveratrol on seric vascular endothelial growth factor concentrations during atherosclerosis

INTRODUCTION

Although it is known that resveratrol has anti-inflammatory and anti-atherogenic actions, its effect on vascular endothelial growth factor (VEGF) in atherosclerosis is unknown.

OBJECTIVE

To evaluate the effect of resveratrol on serum concentrations of VEGF during the progression and evolution of atherosclerosis, as well as and its evolution over time in rabbits fed with a cholesterol diet.

MATERIALS AND METHODS

A total of 48 New Zealand white male rabbits were randomly divided into four groups of 12 rabbits: group1 (control): standard diet (commercial rabbit food); group2: cholesterol diet (0.5% cholesterol); group3 (control resveratrol): standard diet (commercial rabbit food) and resveratrol (2mg/Kg); group4: cholesterol diet (0.5% cholesterol) and resveratrol (2mg/Kg), for 12weeks. Blood samples of overnight-fasted rabbits were collected at baseline and the sixth and twelfth weeks, and the lipid profile, VEGF, and C-reactive protein (CRP) levels were determined. Half of the animals were sacrificed on the sixth or twelfth week, and the aorta was dissected for histological studies.

RESULTS

VEGF and CRP levels were significantly higher in groups2 and 4 than in groups1 and 3, respectively, from the 6th week (p<0.001). VEGF and CRP were significantly lower in group4 than in group2 on 12th week (p<0.004). Supplementation of resveratrol reduced the formation of atherosclerotic lesions.

CONCLUSIONS

Serum VEGF and CRP levels are early markers of atherosclerosis. Oral supplementation of resveratrol exerts anti-inflammatory and anti-atherosclerotic effects, decreasing serum concentrations of VEGF and CRP and the formation and evolution of atherosclerotic lesions.

Oxyresveratrol prevents murine H22 hepatocellular carcinoma growth and lymph node metastasis via inhibiting tumor angiogenesis and lymphangiogenesis

The purpose of this study was to investigate the effects and mechanisms of oxyresveratrol (Oxyres) on hepatocellular carcinoma (HCC) in vitro and in vivo. The MTT and Transwell assays were performed to investigate the effects of Oxyres on cell proliferation and migration of two HCC cell lines, QGY-7701 and SMMC-7721 cells. H22 cells were subcutaneously injected into hind foot pads of 70 male mice to establish a lymph node metastasis model. These mice were randomly divided into seven groups as follows, control group, HCC group, Oxyres 20 mg/kg group, Oxyres 40 mg/kg group, Oxyres 60 mg/kg group, Resveratrol (Res) group, and Adriamycin (ADM) group. Oxyres, Res, and ADM were intraperitoneally injected daily for consecutive 21 days. Tumors and popliteal lymph node were isolated and embedded for histology analysis. Expressions of CD31 and vascular endothelial growth factor receptor-3 (VEGFR3) in tumors were detected by immunohistocehmistry. Expressions of vascular endothelial growth factor C (VEGF-C) were measured by Western blot. Oxyres significantly inhibited the proliferation and migration of QGY-7701 and SMMC-7721 cells. Oxyres significantly inhibited tumor growth (p < 0.001) and metastasis to sentinel lymph nodes (70%) in a dose-dependent manner. Oxyres showed a similar inhibition rate as Res. Oxyres also significantly decreased micro-blood vessel density and micro-lymphatic vessel density in tumors (p < 0.05). Expressions of CD31, VEGFR3, and VEGF-C of tumors were also inhibited by Oxyres (p < 0.05). Oxyres exerts anti-tumor effects against HCC through inhibiting both angiogenesis and lymph node metastasis, which suggests Oxyres be a potential therapeutic agent.

Selected Metabolic Markers in Girls with Turner Syndrome: A Pilot Study

BACKGROUND

Turner syndrome (TS) predisposes an individual to obesity and related metabolic disorders. As the TS population is at a higher risk of cardiovascular diseases and malformations, research into laboratory markers of metabolic complications has been ongoing. Special significance has recently been attributed to matrix metalloproteinases (MMPs), their inhibitors (TIMPs), and neurotrophic factors, such as BDNF and GDNF.

OBJECTIVE

To establish whether cardiometabolic risk in patients with TS is reflected in the concentrations of metalloproteinases and neurotrophic factors.

METHOD

The concentrations of circulating MMP-1, MMP-2, MMP-9, TIMP-1, BDNF, GDNF, and VEGF were measured in 17 patients with TS. The control group was composed of 11 girls with nonpathologic short stature and normal karyotype.

RESULTS

There were no differences in chronological or bone age. No significant differences were observed in mean weight, although the Z-score BMI was higher in the study group. The mean baseline values of MMP-1 and BDNF were significantly lower in the control group than in the study group (p < 0.001, p = 0.001). Regression analysis revealed a positive correlation between MMP-1 concentrations and Z-score BMI (r = 0.36, p = 0.047) and between BDNF and Z-score BMI (r = 0.48, p = 0.013).

CONCLUSION

Our pilot study showed that MMP-1 may be a potential indicator of a higher risk of cardiometabolic complications in girls with TS. The elevated concentrations of BDNF in normal-weight girls with TS need to be studied further, taking into consideration the influence of estrogen-androgen imbalance.

The Lymphatic Vasculature: Its Role in Adipose Metabolism and Obesity

Obesity is a key risk factor for metabolic and cardiovascular diseases, and although we understand the mechanisms regulating weight and energy balance, the causes of some forms of obesity remain enigmatic. Despite the well-established connections between lymphatics and lipids, and the fact that intestinal lacteals play key roles in dietary fat absorption, the function of the lymphatic vasculature in adipose metabolism has only recently been recognized. It is well established that angiogenesis is tightly associated with the outgrowth of adipose tissue, as expanding adipose tissue requires increased nutrient supply from blood vessels. Results supporting a crosstalk between lymphatic vessels and adipose tissue, and linking lymphatic function with metabolic diseases, obesity, and adipose tissue, also started to accumulate in the last years. Here we review our current knowledge of the mechanisms by which defective lymphatics contribute to obesity and fat accumulation in mouse models, as well as our understanding of the lymphatic-adipose tissue relationship.

Overweight and obesity versus concentrations of VEGF-A, sVEGFR-1, and sVEGFR-2 in plasma of patients with lower limb chronic ischemia

OBJECTIVE

Being overweight or obese comprises a significant risk factor for atherosclerosis. Fat tissue also generates factors stimulating angiogenesis, the process by which new blood vessels form. The purpose of this paper is to assess concentrations of the vascular endothelial growth factor A (VEGF-A) and its soluble type-1 and type-2 receptors (sVEGFR-1 and sVEGFR-2) in plasma of patients with peripheral arterial disease (PAD) depending on the level of nutrition according to body mass index (BMI).

METHODS

The study group included patients suffering from symptomatic PAD (n=46) in Fontaine classes IIa-IV without any history of neoplastic disease and who have a normal BMI (n=15), are overweight (n=21) or are obese (n=10). The control group (n=30) consisted of healthy non-smoking volunteers who were neither overweight nor obese. Venous blood plasma samples were collected from both groups at rest in the morning to determine plasma concentrations of VEGF-A, sVEGFR-1, and sVEGFR-2 using the enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

The group of patients with PAD co-existent with being overweight or obese tended to have higher mean concentration levels of VEGF-A and sVEGFR-2 when compared with patients suffering from PAD with normal BMI. A statistically significant positive correlation was obtained between BMI and average plasma concentrations of sVEGFR-2 (R=0.37, P=0.0103). However, no significant correlation was noticed between BMI and VEGF-A or sVEGFR-1 concentrations.

CONCLUSIONS

A positive correlation determined between the level of antiangiogenic factor and BMI value may be indicative of the linearly growing prevalence of some antiangiogenic factors in patients with metabolic disorders, which may be one of numerous factors contributing to incomplete efficiency of collateral circulation development in patients with PAD.

No causal impact of serum vascular endothelial growth factor level on temporal changes in body mass index in Japanese male workers: a five-year longitudinal study

PURPOSE

It has been reported that adipocytes secrete vascular endothelial growth factor. Therefore, we conducted a 5-year longitudinal epidemiological study to further elucidate the association between vascular endothelial growth factor levels and temporal changes in body mass index.

METHODS

Our study subjects were Japanese male workers, who had regular health check-ups. Vascular endothelial growth factor levels were measured at baseline. To examine the association between vascular endothelial growth factor levels and overweight, we calculated the odds ratio using a multivariate logistic regression model. Moreover, linear mixed effect models were used to assess the association between vascular endothelial growth factor level and temporal changes in body mass index during the 5-year follow-up period.

RESULTS

Vascular endothelial growth factor levels were marginally higher in subjects with a body mass index greater than 25 kg/m² compared with in those with a body mass index less than 25 kg/m² (505.4 vs. 465.5 pg/mL, P = 0.1) and were weakly correlated with leptin levels (β: 0.05, P = 0.07). In multivariate logistic regression, subjects in the highest vascular endothelial growth factor quantile were significantly associated with an increased risk for overweight compared with those in the lowest quantile (odds ratio 1.65, 95 % confidential interval: 1.10-2.50). Moreover P for trend was significant (P for trend = 0.003). However, the linear mixed effect model revealed that vascular endothelial growth factor levels were not associated with changes in body mass index over a 5-year period (quantile 2, β: 0.06, P = 0.46; quantile 3, β: -0.06, P = 0.45; quantile 4, β: -0.10, P = 0.22; quantile 1 as reference).

CONCLUSIONS

Our results suggested that high vascular endothelial growth factor levels were significantly associated with overweight in Japanese males but high vascular endothelial growth factor levels did not necessarily cause obesity.

High Triglycerides Are Associated with Low Thrombocyte Counts and High VEGF in Nephropathia Epidemica

Nephropathia epidemica (NE) is a mild form of hemorrhagic fever with renal syndrome. Several reports have demonstrated a severe alteration in lipoprotein metabolism. However, little is known about changes in circulating lipids in NE. The objectives of this study were to evaluate changes in serum total cholesterol, high density cholesterol (HDCL), and triglycerides. In addition to evaluation of serum cytokine activation associations, changes in lipid profile and cytokine activation were determined for gender, thrombocyte counts, and VEGF. Elevated levels of triglycerides and decreased HDCL were observed in NE, while total cholesterol did not differ from controls. High triglycerides were associated with both the lowest thrombocyte counts and high serum VEGF, as well as a high severity score. Additionally, there were higher levels of triglycerides in male than female NE patients. Low triglycerides were associated with upregulation of IFN-γ and IL-12, suggesting activation of Th1 helper cells. Furthermore, levels of IFN-γ and IL-12 were increased in patients with lower severity scores, suggesting that a Th1 type immune response is playing protective role in NE. These combined data advance the understanding of NE pathogenesis and indicate a role for high triglycerides in disease severity.

Transgenic overexpression of VEGF-C induces weight gain and insulin resistance in mice

Obesity comprises great risks for human health, contributing to the development of other diseases such as metabolic syndrome, type 2 diabetes and cardiovascular disease. Previously, obese patients were found to have elevated serum levels of VEGF-C, which correlated with worsening of lipid parameters. We recently identified that neutralization of VEGF-C and -D in the subcutaneous adipose tissue during the development of obesity improves metabolic parameters and insulin sensitivity in mice. To test the hypothesis that VEGF-C plays a role in the promotion of the metabolic disease, we used K14-VEGF-C mice that overexpress human VEGF-C under control of the keratin-14 promoter in the skin and monitored metabolic parameters over time. K14-VEGF-C mice had high levels of VEGF-C in the subcutaneous adipose tissue and gained more weight than wildtype littermates, became insulin resistant and had increased ectopic lipid accumulation at 20 weeks of age on regular mouse chow. The metabolic differences persisted under high-fat diet induced obesity. These results indicate that elevated VEGF-C levels contribute to metabolic deterioration and the development of insulin resistance, and that blockade of VEGF-C in obesity represents a suitable approach to alleviate the development of insulin resistance.

Loss of Adipocyte VEGF Impairs Endurance Exercise Capacity in Mice

PURPOSE

Reducing vascular endothelial growth factor (VEGF) in adipose tissue alters adipose vascularity and metabolic homeostasis. We hypothesized that this would also affect metabolic responses during exercise-induced stress and that adipocyte-specific VEGF-deficient (adipoVEGF-/-) mice would have impaired endurance capacity.

METHODS

Endurance exercise capacity in adipoVEGF-/- (n = 10) and littermate control (n = 11) mice was evaluated every 4 wk between 6 and 24 wk of age using a submaximal endurance run to exhaustion at 20 m·min(-1) at 10° incline. Maximal running speed, using incremental increases in speed at 30-s intervals, was tested at 25 and 37 wk of age.

RESULTS

White and brown adipose tissue capillarity were reduced by 40% in adipoVEGF-/-, and no difference in skeletal muscle capillarity was observed. Endurance run time to exhaustion was 30% lower in adipoVEGF-/- compared with that in controls at all time points (P < 0.001), but no difference in maximal running speed was observed between the groups. After exercise (1 h at 50% maximum running speed), adipoVEGF-/- mice displayed lower circulating insulin (P < 0.001), lower glycerol (P < 0.05), and tendency for lower blood glucose (P = 0.06) compared with controls. There was no evidence of altered oxidative damage or changes in carnitine palmitoyltransferase-1β expression in skeletal muscle of adipoVEGF-/- mice.

CONCLUSIONS

These data suggest that VEGF-mediated deficits in adipose tissue blunt the availability of lipid substrates during endurance exercise, which likely reduced endurance performance. Surprisingly, we also found an unchanged basal blood glucose despite lower circulating insulin in adipoVEGF-/- mice, suggesting that loss of adipocyte VEGF can blunt insulin release and/or increase basal insulin sensitivity.

Network-driven plasma proteomics expose molecular changes in the Alzheimer's brain

Background

Biological pathways that significantly contribute to sporadic Alzheimer’s disease are largely unknown and cannot be observed directly. Cognitive symptoms appear only decades after the molecular disease onset, further complicating analyses. As a consequence, molecular research is often restricted to late-stage post-mortem studies of brain tissue. However, the disease process is expected to trigger numerous cellular signaling pathways and modulate the local and systemic environment, and resulting changes in secreted signaling molecules carry information about otherwise inaccessible pathological processes.

Results

To access this information we probed relative levels of close to 600 secreted signaling proteins from patients’ blood samples using antibody microarrays and mapped disease-specific molecular networks. Using these networks as seeds we then employed independent genome and transcriptome data sets to corroborate potential pathogenic pathways.

Conclusions

We identified Growth-Differentiation Factor (GDF) signaling as a novel Alzheimer’s disease-relevant pathway supported by in vivo and in vitro follow-up experiments, demonstrating the existence of a highly informative link between cellular pathology and changes in circulatory signaling proteins.

Electronic supplementary material

The online version of this article (doi:10.1186/s13024-016-0095-2) contains supplementary material, which is available to authorized users.

Lipoprotein subfractions by nuclear magnetic resonance are associated with tumor characteristics in breast cancer

Background

High-Density Lipoprotein (HDL)-cholesterol, has been associated with breast cancer development, but the association is under debate, and whether lipoprotein subfractions is associated with breast tumor characteristics remains unclear.

Methods

Among 56 women with newly diagnosed invasive breast cancer stage I/II, aged 35–75 years, pre-surgery overnight fasting serum concentrations of lipids were assessed, and body mass index (BMI) was measured. All breast tumors were immunohistochemically examined in the surgical specimen. Serum metabolomics of lipoprotein subfractions and their contents of cholesterol, free cholesterol, phospholipids, apolipoprotein-A1 and apolipoprotein-A2, were assessed using nuclear magnetic resonance. Principal component analysis, partial least square analysis, and uni- and multivariable linear regression models were used to study whether lipoprotein subfractions were associated with breast cancer tumor characteristics.

Results

The breast cancer patients had following means: age at diagnosis: 55.1 years; BMI: 25.1 kg/m²; total-Cholesterol: 5.74 mmol/L; HDL-Cholesterol: 1.78 mmol/L; Low-Density Lipoprotein (LDL)-Cholesterol: 3.45 mmol/L; triglycerides: 1.18 mmol/L. The mean tumor size was 16.4 mm, and the mean Ki67 hotspot index was 26.5 %. Most (93 %) of the patients had estrogen receptor (ER) positive tumors (≥1 % ER+), and 82 % had progesterone receptor (PgR) positive tumors (≥10 % PgR+). Several HDL subfraction contents were strongly associated with PgR expression: Apolipoprotein-A1 (β 0.46, CI 0.22–0.69, p < 0.001), HDL cholesterol (β 0.95, CI 0.51–1.39, p < 0.001), HDL free cholesterol (β 2.88, CI 1.28–4.48, p = 0.001), HDL phospholipids (β 0.70, CI 0.36–1.04, p < 0.001). Similar results were observed for the subfractions of HDL1-3. We observed inverse associations between HDL phospholipids and Ki67 (β -0.25, p = 0.008), and in particular between HDL1’s contents of cholesterol, phospholipids, apolipoprotein-A1, apolipoprotein-A2 and Ki67. No association was observed between lipoproteins and ER expression.

Conclusion

Our findings hypothesize associations between different lipoprotein subfractions, and PgR expression, and Ki 67 % in breast tumors. These findings may have clinical implications, but require confirmation in larger studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-016-0225-4) contains supplementary material, which is available to authorized users.

Inhibition of Inflammation and iNOS Improves Lymphatic Function in Obesity

Although recent studies have shown that obesity decreases lymphatic function, the cellular mechanisms regulating this response remain unknown. In the current study, we show that obesity results in perilymphatic accumulation of inflammatory cells and that local inhibition of this response with topical tacrolimus, an inhibitor of T cell differentiation, increases lymphatic vessel density, decreases perilymphatic iNOS expression, increases lymphatic vessel pumping frequency, and restores lymphatic clearance of interstitial fluid to normal levels. Although treatment of obese mice with 1400W, a selective inhibitor of iNOS, also improved lymphatic collecting vessel contractile function, it did not completely reverse lymphatic defects. Mice deficient in CD4(+) cells fed a high fat diet also gained weight relative to controls but were protected from lymphatic dysfunction. Taken together, our findings suggest that obesity-mediated lymphatic dysfunction is regulated by perilymphatic accumulation of inflammatory cells and that T cell inflammatory responses are necessary to initiate this effect.

Dietary energy balance modulates ovarian cancer progression and metastasis

A high energy balance, or caloric excess, accounts as a tumor promoting factor, while a negative energy balance via caloric restriction, has been shown to delay cancer progression. The effect of energy balance on ovarian cancer progression was investigated in an isogeneic immunocompetent mouse model of epithelial ovarian cancer kept on a regimen of regular diet, high energy diet (HED) and calorie restricted diet (CRD), prior to inoculating the animals intraperitoneally with the mouse ovarian surface epithelial ID8 cancer cells. Tumor evaluation revealed that mice group on HED displayed the most extensive tumor formation with the highest tumor score at all organ sites (diaphragm, peritoneum, bowel, liver, kidney, spleen), accompanied with increased levels of insulin, leptin, insulin growth factor-1 (IGF-1), monocyte chemoattractant protein-1 (MCP-1), VEGF and interleukin 6 (IL-6). On the other hand, the mice group on CRD exhibited the least tumor burden associated with a significant reduction in levels of insulin, IGF-1, leptin, MCP-1, VEGF and IL-6. Immunohistochemistry analysis of tumors from HED mice showed higher activation of Akt and mTOR with decreased adenosine monophosphate activated kinase (AMPK) and SIRT1 activation, while tumors from the CRD group exhibited the reverse profile. In conclusion, ovarian cancer growth and metastasis occurred more aggressively under HED conditions and was significantly curtailed under CRD. The suggested mechanism involves modulated secretion of growth factors, cytokines and altered regulation of AMPK and SIRT1 that converges on mTOR inhibition. While the role of a high energy state in ovarian cancer has not been confirnmed in the literature, the current findings support investigating the potential impact of diet modulation as adjunct to other anticancer therapies and as possible individualized treatment strategy of epithelial ovarian cancer.

Blockade of VEGF-C and VEGF-D modulates adipose tissue inflammation and improves metabolic parameters under high-fat diet

OBJECTIVE

Elevated serum levels of the lymphangiogenic factors VEGF-C and -D have been observed in obese individuals but their relevance for the metabolic syndrome has remained unknown.

METHODS

K14-VEGFR-3-Ig (sR3) mice that constitutively express soluble-VEGFR-3-Ig in the skin, scavenging VEGF-C and -D, and wildtype (WT) mice were fed either chow or high-fat diet for 20 weeks. To assess the effect of VEGFR-3 blockage on adipose tissue growth and insulin sensitivity, we evaluated weight gain, adipocyte size and hepatic lipid accumulation. These results were complemented with insulin tolerance tests, FACS analysis of adipose tissue macrophages, in vitro 3T3-L1 differentiation assays and in vivo blocking antibody treatment experiments.

RESULTS

We show here that sR3 mice are protected from obesity-induced insulin resistance and hepatic lipid accumulation. This protection is associated with enhanced subcutaneous adipose tissue hyperplasia and an increased number of alternatively-activated (M2) macrophages in adipose tissue. We also show that VEGF-C and -D are chemotactic for murine macrophages and that this effect is mediated by VEGFR-3, which is upregulated on M1 polarized macrophages. Systemic antibody blockage of VEGFR-3 in db/db mice reduces adipose tissue macrophage infiltration and hepatic lipid accumulation, and improves insulin sensitivity.

CONCLUSIONS

These results reveal an unanticipated role of the lymphangiogenic factors VEGF-C and -D in the mediation of metabolic syndrome-associated adipose tissue inflammation. Blockage of these lymphangiogenic factors might constitute a new therapeutic strategy for the prevention of obesity-associated insulin resistance.

A preliminary evaluation of VEGF-A, VEGFR1 and VEGFR2 in patients with well-controlled type 2 diabetes mellitus

OBJECTIVE

Decompensated chronic hyperglycemia often leads to late microvascular complications such as retinopathy, diabetic foot syndrome, and diabetic kidney disease. The aim of this study was to determine the concentration of vascular endothelial growth factor A (VEGF-A) and its receptors in patients with well-controlled diabetes.

METHODS

The study was conducted on 31 patients with well-controlled type 2 diabetes without micro- or macroangiopathy. Thirty healthy volunteers were enrolled in a control group. Serum concentrations of VEGF-A, VEGF receptors 1 and 2 (VEGFR1 and VEGFR2), fasting glucose, and lipid profiles were measured, and the plasma concentration of glycated hemoglobin (HbA1c) was determined.

RESULTS

No significant differences were observed between the concentration of VEGF-A, VEGFR1 or VEGFR2 in the subject group and that in the control group. Positive correlations were noted between the levels of VEGF-A, VEGFR2, and triglyceride, and there was a negative correlation between the levels of VEGFR2 and high-density lipoprotein (HDL)-cholesterol in the study group.

CONCLUSIONS

The concentrations of VEGF-A and its receptors 1 and 2 in patients with well-controlled diabetes are comparable to those of healthy individuals, which may indicate that appropriate control of glucose levels delays the occurrence of vascular complications. A negative correlation between VEGFR2 and HDL-cholesterol levels, and positive correlations between VEGF-A, VEGFR2, and triglyceride levels, suggest that lipid abnormalities occurring in diabetes may be involved in the modulation of angiogenesis.

Impaired adipose tissue expandability and lipogenic capacities as ones of the main causes of metabolic disorders

Obesity is considered a major health problem. However, mechanisms involved and its comorbidities are not elucidated. Recent theories concerning the causes of obesity have focused on a limit to the functional capacity of adipose tissue, comparing it with other vital organs. This assumption has been the central point of interest in our laboratory. We proposed that the failure of adipose tissue is initiated by the difficulty of this tissue to increase its cellularity due to excess in fat contribution, owing to genetic or environmental factors. Nevertheless, why the adipose tissue reduces its capacity to make new adipocytes via mesenchymal cells of the stroma has not yet been elucidated. Thus, we suggest that this tissue ceases fulfilling its main function, the storage of excess fat, thereby affecting some of the key factors involved in lipogenesis, some of which are reviewed in this paper (PPARγ, ROR1, FASN, SCD1, Rab18, BrCa1, ZAG, and FABP4). On the other hand, mechanisms involved in adipose tissue expandability are also impaired, predominating hypertrophy via an increase in apoptosis and a decrease in adipogenesis and angiogenesis. However, adipose tissue failure is only part of this great orchestra, only a chapter of this nightmare.

Obesity inhibits lymphangiogenesis in prostate tumors

Lymphangiogenesis is the process that leads to new lymphatic vessels formation from preexisting blood vessels in the presence of appropriate inducing signals, which in pathologic conditions such as cancer, may contribute to tumor cells dissemination. The aim of the present study was to study the role of obesity, leptin and insulin in tumor lymphangiogenesis. For that, we have quantified the lymphatic vessels in prostate tumors through their immunohistochemistry staining by Lyve-1 in RM1 prostate tumors induced in different obese mice models (ob/ob, db/db and diet induced obese (DIO) and in normal weight C57BL/6J mice (control). Lymph vessels density was determined by Lyve-1 immunohistochemistry of prostate adenocarcinomas, while the percentage of the Lyve-1 stained area and lymphatic vessels number were obtained using a morphometric computerized tool. Obese ob/ob and DIO mice presented prostate tumors that were significantly larger (p<0.001) than controls, while tumors of db/db mice were significantly smaller (p=0.047). Lyve-1 expression was significantly higher in prostate tumors of DIO mice compared to tumors of db/db mice (p<0.05); furthermore Lyve-1 expression was negatively correlated with the percentage of the epididymal fat and body weight (p<0.01). No significantly correlations were found between Lyve-1 expression and tumor weight and leptin or insulin plasma levels. Our results suggest that obesity may have a protective effect against prostate cancer dissemination by inhibiting lymphangiogenesis through a still unidentified mechanism that appears not to involve leptin or insulin.

The obesity-inflammation-eicosanoid axis in breast cancer

Inflammation of the adipose tissues occurs in association with obesity. This inflammatory process leads to the induction of cyclooxygenase-2 (COX-2) expression and a consequent elevation in prostaglandin (PG) production, which, together with proinflammatory cytokines, induce aromatase expression and estrogen synthesis. Infiltrating macrophages support the growth of breast epithelial cells and vascular endothelial cells by producing a milieu of cytokines and growth factors. This scenario creates a microenvironment favorable to breast cancer growth and invasion. The eicosanoids promote further development and growth of breast cancers indirectly by the induction of aromatase, particularly in estrogen positive breast cancers, or by direct stimulatory effect of PGE2 and lipoxygenase (LOX) products on the more aggressive, estrogen-independent tumors. Beyond this, the local production of estrogens and proinflammatory cytokines which occurs in association with breast adipose tissue inflammation, and consequent activation of the estrogen receptor and nuclear factor-κB, provides a mechanism by which breast cancers develop resistance to selective estrogen receptor modulation and aromatase inhibitor therapy. The obesity-inflammation-eicosanoid axis in breast cancer does offer a therapeutic target for the prevention of relapse in breast cancer by improving the efficacy of antiaromatase therapy using COX/LOX inhibitors; however, careful consideration of menopausal status and obesity in patients is warranted.

Atherosclerosis and transit of HDL through the lymphatic vasculature

Key components of atherosclerotic plaque known to drive disease progression are macrophages and cholesterol. It has been widely understood, and bolstered by recent evidence, that the efflux of cholesterol from macrophage foam cells quells disease progression or even to promote regression. Following macrophage cholesterol efflux, cholesterol loaded onto HDL must be removed from the plaque environment. Here, we focus on recent evidence that the lymphatic vasculature is critical for the removal of cholesterol, likely as a component of HDL, from tissues including skin and the artery wall. We discuss the possibility that progression of atherosclerosis might in part be linked to sluggish removal of cholesterol from the plaque.

Neurokinin-1 receptor, a new modulator of lymphangiogenesis in obese-asthma phenotype

AIMS

Obesity and asthma are widely prevalent and associated disorders. Recent studies of our group revealed that Substance P (SP) is involved in pathophysiology of obese-asthma phenotype in mice through its selective NK1 receptor (NK1-R). Lymphangiogenesis is impaired in asthma and obesity, and SP activates contractile and inflammatory pathways in lymphatics. Our aim was to study whether NK1-R expression was involved in lymphangiogenesis on visceral (VAT) and subcutaneous (SAT) adipose tissues and in the lungs, in obese-allergen sensitized mice.

MAIN METHODS

Diet-induced obese and ovalbumin (OVA)-sensitized Balb/c mice were treated with a selective NK1-R antagonist (CJ 12,255, Pfizer Inc., USA) or placebo. Lymphatic structures (LYVE-1+) and NK1-R expression were analyzed by immunohistochemistry. A semi-quantitative score methodology was used for NK1-R expression.

KEY FINDINGS

Obesity and allergen-sensitization together increased the number of LYVE-1+ lymphatics in VAT and decreased it in SAT and lungs. NK1-R was mainly expressed on adipocyte membranes of VAT, blood vessel areas of SAT, and in lung epithelium. Obesity and allergen-sensitization combined increased the expression of NK1-R in VAT, SAT and lungs. NK1-R antagonist treatment reversed the effects observed in lymphangiogenesis in those tissues.

SIGNIFICANCE

The obese-asthma phenotype in mice is accompanied by increased expression of NK1-R on adipose tissues and lung epithelium, reflecting that SP released during inflammation may act directly on these tissues. Blocking NK1-R affects lymphangiogenesis, implying a role of SP, with opposite physiological consequences in VAT, and in SAT and lungs. Our results provide a clue for a novel SP role in the obese-asthma phenotype.

Effectiveness of intravitreal ranibizumab in exudative age-related macular degeneration (AMD): comparison between typical neovascular AMD and polypoidal choroidal vasculopathy over a 1 year follow-up

BACKGROUND

The effects of intravitreal ranibizumab (IVR) against exudative age-related macular degeneration (AMD) may be different associated with the lesion phenotype. This study was conducted to compare the outcomes of IVR between two different phenotypes of exudative AMD: typical neovascular AMD (tAMD) and polypoidal choroidal vasculopathy (PCV).

METHODS

This is a retrospective cohort study of 54 eyes from 54 subfoveal exudative AMD patients (tAMD 24, PCV 30 eyes). Three consecutive IVR treatments (0.5 mg) were performed every month, followed by re-injections as needed. Change in the best-corrected visual acuity (BCVA) and central retinal thickness (CRT) were then compared between the tAMD and PCV groups over 12 months of follow-up.

RESULTS

The mean BCVA was significantly improved (-0.11 logMAR units) at month 3 after the initial IVR (p <0 .001, Wilcoxon signed-rank test), and was sustained up to 12 months in all AMD patients (p =0.02). In the subgroup analysis, the tAMD group showed a significant improvement in their mean BCVA (-0.06, -0.17, -0.15 and -0.16 logMAR units at 1, 3, 6 and 12 months, respectively), but there was only a slight but non-significant improvement in the PCV group. The improvement in the BCVA was significantly greater in the tAMD group than in the PCV group (p = 0.043, repeated measures ANOVA) over 12 months. Both phenotypes showed significant improvements in the CRT during 12 months after the initial IVR.

CONCLUSIONS

IVR is an effective therapy for tAMD and PCV in the BCVA improvement in Japanese patients over 12 months of follow-up. The phenotype of tAMD showed a significantly better outcome with IVR than PCV in terms of BCVA improvement.

An in vivo method to quantify lymphangiogenesis in zebrafish

Background

Lymphangiogenesis is a highly regulated process involved in the pathogenesis of disease. Current in vivo models to assess lymphangiogenesis are largely unphysiologic. The zebrafish is a powerful model system for studying development, due to its rapid growth and transparency during early stages of life. Identification of a network of trunk lymphatic capillaries in zebrafish provides an opportunity to quantify lymphatic growth in vivo.

Methods and Results

Late-phase microangiography was used to detect trunk lymphatic capillaries in zebrafish 2- and 3-days post-fertilization. Using this approach, real-time changes in lymphatic capillary development were measured in response to modulators of lymphangiogenesis. Recombinant human vascular endothelial growth factor (VEGF)-C added directly to the zebrafish aqueous environment as well as human endothelial and mouse melanoma cell transplantation resulted in increased lymphatic capillary growth, while morpholino-based knockdown of vegfc and chemical inhibitors of lymphangiogenesis added to the aqueous environment resulted in decreased lymphatic capillary growth.

Conclusion

Lymphatic capillaries in embryonic and larval zebrafish can be quantified using late-phase microangiography. Human activators and small molecule inhibitors of lymphangiogenesis, as well as transplanted human endothelial and mouse melanoma cells, alter lymphatic capillary development in zebrafish. The ability to rapidly quantify changes in lymphatic growth under physiologic conditions will allow for broad screening of lymphangiogenesis modulators, as well as help define cellular roles and elucidate pathways of lymphatic development.