Angiogenesis and biomarkers of cardiovascular risk in adults with metabolic syndrome

Reduced myocardial work in asymptomatic heavy alcohol use and its correlation with epicardial adipose tissue volume and serum biomarkers

BACKGROUND

It is unclear whether long-term heavy alcohol use leads to early cardiac function decline.

HYPOTHESIS

Long-term heavy alcohol use developed reduced cardiac function in subclinical status by analyzing myocardial work (MW). Epicardial adipose tissue (EAT) volume and serum biomarkers contribute to identify potential factors sensitive in predicting early cardiac function decline.

METHODS

We enrolled 31 asymptomatic participants with heavy alcohol use and 33 age and sex-matching nondrinking individuals. Participants underwent echocardiography, MW analysis, EAT volume measurement, serum biochemical examinations, and body composition assessment. We used multivariate linear regression to identify correlation between MW and total cholesterol (TC), EAT volume, and placental growth factor (PlGF). To determine global work efficiency (GWE) below the normal reference value of 96%, we developed receiver operating curves with area under curve (AUC) to compare different combinations of TC, EAT volume, and PlGF.

RESULTS

All 64 participants were male. GWE was reduced in the alcohol use group compared with the control group (96, interquartile range [IQR] = [95-97.75] vs. 97, IQR = [97-98], p = .004). TC was positively associated with GWE (β = .434, 95% confidence interval [CI] = 0.228 to 1.328, p = .008), whereas EAT volume (β = -.398, 95% CI = -0.000446 to -0.000093, p = .005) and PlGF (β = -.493, 95% CI = -1.010 to -0.230, p = .004) were inversely associated with GWE. The most significant AUC for reduced GWE was TC + EAT volume (0.851, 95% CI = 0.671 to 1, p = .006).

CONCLUSION

Asymptomatic heavy alcohol use has shown early reduced cardiac function which can be associated with altered fat metabolism, suggesting individuals with alcohol use and abnormal fat metabolism need to be alert to heart damage.

Genetics of PlGF plasma levels highlights a role of its receptors and supports the link between angiogenesis and immunity

Placental growth factor (PlGF) is a member of the vascular endothelial growth factor family and is involved in bone marrow-derived cell activation, endothelial stimulation and pathological angiogenesis. High levels of PlGF have been observed in several pathological conditions especially in cancer, cardiovascular, autoimmune and inflammatory diseases. Little is known about the genetics of circulating PlGF levels. Indeed, although the heritability of circulating PlGF levels is around 40%, no studies have assessed the relation between PlGF plasma levels and genetic variants at a genome-wide level. In the current study, PlGF plasma levels were measured in a population-based sample of 2085 adult individuals from three isolated populations of South Italy. A GWAS was performed in a discovery cohort (N = 1600), followed by a de novo replication (N = 468) from the same populations. The meta-analysis of the discovery and replication samples revealed one signal significantly associated with PlGF circulating levels. This signal was mapped to the PlGF co-receptor coding gene NRP1, indicating its important role in modulating the PlGF plasma levels. Two additional signals, at the PlGF receptor coding gene FLT1 and RAPGEF5 gene, were identified at a suggestive level. Pathway and TWAS analyses highlighted genes known to be involved in angiogenesis and immune response, supporting the link between these processes and PlGF regulation. Overall, these data improve our understanding of the genetic variation underlying circulating PlGF levels. This in turn could lead to new preventive and therapeutic strategies for a wide variety of PlGF-related pathologies.

Therapeutic angiogenesis in coronary artery disease: a review of mechanisms and current approaches

INTRODUCTION

Despite tremendous advances, the shortcomings of current therapies for coronary disease are evidenced by the fact that it remains the leading cause of death in many parts of the world. There is hence a drive to develop novel therapies to tackle this disease. Therapeutic approaches to coronary angiogenesis have long been an area of interest in lieu of its incredible, albeit unrealized potential.

AREAS COVERED

This paper offers an overview of mechanisms of native angiogenesis and a description of angiogenic growth factors. It progresses to outline the advances in gene and stem cell therapy and provides a brief description of other investigational approaches to promote angiogenesis. Finally, the hurdles and limitations unique to this particular area of study are discussed.

EXPERT OPINION

An effective, sustained, and safe therapeutic option for angiogenesis truly could be the paradigm shift for cardiovascular medicine. Unfortunately, clinically meaningful therapeutic options remain elusive because promising animal studies have not been replicated in human trials. The sheer complexity of this process means that numerous major hurdles remain before therapeutic angiogenesis truly makes its way from the bench to the bedside.

Hyperglycaemia up-regulates placental growth factor (PlGF) expression and secretion in endothelial cells via suppression of PI3 kinase-Akt signalling and activation of FOXO1

Placenta growth factor (PlGF) is a pro-inflammatory angiogenic mediator that promotes many pathologies including diabetic complications and atherosclerosis. Widespread endothelial dysfunction precedes the onset of these conditions. As very little is known of the mechanism(s) controlling PlGF expression in pathology we investigated the role of hyperglycaemia in the regulation of PlGF production in endothelial cells. Hyperglycaemia stimulated PlGF secretion in cultured primary endothelial cells, which was suppressed by IGF-1-mediated PI3K/Akt activation. Inhibition of PI3K activity resulted in significant PlGF mRNA up-regulation and protein secretion. Similarly, loss or inhibition of Akt activity significantly increased basal PlGF expression and prevented any further PlGF secretion in hyperglycaemia. Conversely, constitutive Akt activation blocked PlGF secretion irrespective of upstream PI3K activity demonstrating that Akt is a central regulator of PlGF expression. Knock-down of the Forkhead box O-1 (FOXO1) transcription factor, which is negatively regulated by Akt, suppressed both basal and hyperglycaemia-induced PlGF secretion, whilst FOXO1 gain-of-function up-regulated PlGF in vitro and in vivo. FOXO1 association to a FOXO binding sequence identified in the PlGF promoter also increased in hyperglycaemia. This study identifies the PI3K/Akt/FOXO1 signalling axis as a key regulator of PlGF expression and unifying pathway by which PlGF may contribute to common disorders characterised by endothelial dysfunction, providing a target for therapy.

Biomarkers and Their Relation to Cardiac Function Late After Peripartum Cardiomyopathy

BACKGROUND

Angiogenic imbalance involving the placental protein soluble Fms-like tyrosine kinase-1 (sFlt-1) and cleavage of the nursing-hormone prolactin by the enzyme cathepsin D (CD) both play a role in the pathogenesis of peripartum cardiomyopathy (PPCM). We hypothesized that angiogenic imbalance and increased activity of CD have a long-lasting impact in women with PPCM.

METHODS AND RESULTS

A nationwide Danish cohort of women with PPCM (PPCM group, n = 28), age matched women with previous preeclampsia (n = 28) and uncomplicated pregnancies (n = 28) participated in a follow-up study including biomarker analysis, exercise testing and cardiac magnetic resonance imaging. The median time to follow-up was 91 months (range 27-137 months) for the PPCM group. Levels of sFlt-1, placental growth factor, N-terminal pro-natriuretic brain peptide, and copeptin were all significantly higher in the PPCM group. More women in the PPCM group had detectable CD activity (68%) compared with the preeclampsia group (29%) and uncomplicated pregnancies group (36%) (P = .0002). Levels of angiogenic factors and biomarkers correlated inversely with maximal exercise capacity and cardiac functional parameters assessed with cardiac magnetic resonance imaging.

CONCLUSIONS

Women with PPCM had higher biomarker levels and CD activity up to 7 years after diagnosis. Higher biomarker levels correlated inversely with maximal exercise capacity and markers of cardiac dysfunction suggesting that persistent angiogenic imbalance and increased CD activity is associated with residual cardiac dysfunction.

Immune network dysregulation associated with child neurodevelopmental delay: modulatory role of prenatal alcohol exposure

Background

Evidence suggests that cytokine imbalances may be at the root of deficits that occur in numerous neurodevelopmental disorders, including schizophrenia and autism spectrum disorder. Notably, while clinical studies have demonstrated maternal cytokine imbalances with alcohol consumption during pregnancy—and data from animal models have identified immune disturbances in alcohol-exposed offspring—to date, immune alterations in alcohol-exposed children have not been explored. Thus, here we hypothesized that perturbations in the immune environment as a result of prenatal alcohol exposure will program the developing immune system, and result in immune dysfunction into childhood. Due to the important role of cytokines in brain development/function, we further hypothesized that child immune profiles might be associated with their neurodevelopmental status.

Methods

As part of a longitudinal study in Ukraine, children of mothers reporting low/no alcohol consumption or moderate-to-heavy alcohol consumption during pregnancy were enrolled in the study and received neurodevelopmental assessments. Group stratification was based on maternal alcohol consumption and child neurodevelopmental status resulting in the following groups: A/TD, alcohol-consuming mother, typically developing child; A/ND, alcohol-consuming mother, neurodevelopmental delay in the child; C/TD, control mother (low/no alcohol consumption), typically development child; and C/ND, control mother, neurodevelopmental delay in the child. Forty cytokines/chemokines were measured in plasma and data were analyzed using regression and constrained principle component analysis.

Results

Analyses revealed differential cytokine network activity associated with both prenatal alcohol exposure and neurodevelopmental status. Specifically, alcohol-exposed children showed activation of a cytokine network including eotaxin-3, eotaxin, and bFGF, irrespective of neurodevelopmental status. However, another cytokine network was differentially activated based on neurodevelopmental outcome: A/TD showed activation of MIP-1β, MDC, and MCP-4, and inhibition of CRP and PlGF, with opposing pattern of activation/inhibition detected in the A/ND group. By contrast, in the absence of alcohol-exposure, activation of a network including IL-2, TNF-β, IL-10, and IL-15 was associated with neurodevelopmental delay.

Conclusions

Taken together, this comprehensive assessment of immune markers allowed for the identification of unique immune milieus that are associated with alcohol exposure as well as both alcohol-related and alcohol-independent neurodevelopmental delay. These findings are a critical step towards establishing unique immune biomarkers for alcohol-related and alcohol-independent neurodevelopmental delay.

Association Between Cardiac Natriuretic Peptides and Lipid Profile: a Systematic Review and Meta-Analysis

Cardiac natriuretic peptides (NPs) play a fundamental role in maintaining cardiovascular (CV) and renal homeostasis. Moreover, they also affect glucose and lipid metabolism. We performed a systematic review and meta-analysis of studies investigating the association of NPs with serum lipid profile. A PubMed and Scopus search (2005–2018) revealed 48 studies reporting the association between NPs and components of lipid profile [total cholesterol (TC), low-density lipoprotein cholesterol (LDLc), high-density lipoprotein cholesterol (HDLc) and triglycerides (TG)]. Despite high inconsistency across studies, NPs levels were inversely associated with TC [k = 32; pooled r = −0.09; I² = 90.26%], LDLc [k = 31; pooled r = −0.09; I² = 82.38%] and TG [k = 46; pooled r = −0.11; I² = 94.14%], while they were directly associated with HDLc [k = 41; pooled r = 0.06; I² = 87.94%]. The relationship with LDLc, HDLc and TG lost significance if only studies on special populations (works including subjects with relevant acute or chronic conditions that could have significantly affected the circulating levels of NPs or lipid profile) or low-quality studies were taken into account. The present study highlights an association between higher NP levels and a favorable lipid profile. This confirms and extends our understanding of the metabolic properties of cardiac NPs and their potential in CV prevention.

Biomarkers of Atrial Fibrillation in Metabolic Syndrome

Whether the increased atrial fibrillation (AF) risk in metabolic syndrome (MetS) patients is due to the syndrome as a whole or simply the sum of the risks of its individual component parts is still obscure. These two clinical entities share many pathophysiological links and thus distinction between a casual observation and a significant association is difficult. Biomarkers associated with pathogenesis of AF in the context of MetS have the ability to refine future risk prediction. In the present review we identify circulating substances that could be regarded as potential biomarkers for prediction of incident AF, or of cardiovascular events in the setting of AF in patients with MetS. Cardiac myocyte injury and stress markers (troponin and natriuretic peptides), markers of renal function (glomeral filtration rate, cystatin-C), and inflammation markers/mediators (interleukin- 6, CRP) are promising biomarkers of patients with AF and MetS.

Correlation of plasma B-type natriuretic peptide levels with metabolic risk markers

BACKGROUND AND OBJECTIVE

Natriuretic peptide type B (BNP) is a marker of myocardium injury. This peptide has been associated with metabolic risk markers, although controversy exists in this regard. The aim of the present study was to determine the correlation of plasma BNP levels with metabolic risk parameters.

MATERIALS AND METHODS

A retrospective, observational study that included 152 patients, who were classified according to their clinical diagnosis as patients with metabolic syndrome. Plasma BNP levels and clinical metabolic parameters were assessed by using Spearmańs rank correlation coefficient.

RESULTS

A significant inverse association with weight (r=-.408; p<.0001) and BMI (r=-.443; p<.001) was obtained. While a positive significant association with systolic pressure (r=.324; p<.001) was observed. A significant decrease was found in BNP levels and components of metabolic syndrome. (p<.05).

CONCLUSION

Based on the results from this study, we can conclude that BNP determination could be an adequate metabolic marker.

Association between the expression of vascular endothelial growth factors and metabolic syndrome or its components: a systematic review and meta-analysis

BACKGROUND

Several studies have linked vascular endothelial growth factors (VEGFs) with metabolic syndrome or its components. However, there has been no systematic appraisal of the findings of these studies to date. The current systematic review and meta-analysis was conducted to explore this association.

METHODS

PubMed, EMBASE, the Cochrane library, and clinical trials registries were used to retrieve peer-reviewed clinical studies that had evaluated the association of VEGFs with metabolic syndrome or its components without applying language and date restrictions. The final search was performed on 29 September 2017.

RESULTS

We included 32 studies in this systematic review and meta-analysis, of which 16 studies (19 study arms) were included in the meta-analysis and remaining studies were qualitatively assessed. Overall, VEGF-A, VEGF-B and VEGF-C were strongly associated with metabolic syndrome or its components. The components of metabolic syndrome varied in their association. Obesity was not correlated with increased VEGF-A expression (p = 0.12), whereas VEGF-B and VEGF-C expression was significantly higher in those with obesity. In contrast, hyperglycemia in type 1 diabetes was strongly associated with increased VEGF-A levels (p < 0.00001), as was type 2 diabetes (p = 0.0006). The studies included in the qualitative analysis similarly showed an increase in VEGF family expression in people with metabolic syndrome, and with its components.

CONCLUSION

The increased concentrations of vascular endothelial growth factors are variably associated with metabolic syndrome or its components. Each VEGF protein has a unique set of associations with the disease state.

Important signals regulating coronary artery angiogenesis

Angiogenesis is a complex process of budding, the formation of new blood vessels from pre-existing microvessels, via migration, proliferation and survival. Vascular angiogenesis factors include different classes of molecules that have a fundamental role in blood vessel formation. Numerous inducers of angiogenesis, such as the members of the vascular endothelial growth factor (VEGF) family, basic fibroblast growth factor (bFGF), angiopoietin (Ang), hepatocyte growth factor (HGF), and hypoxia inducible factor-1 (HIF-1), have an important role in angiogenesis. However, VEGF, platelet-derived growth factor (PDGF), and transforming growth factor β (TGF-β) expression appear to be important in intraplaque angiogenesis. Interaction and combined effects between growth factors is essential in endothelial cell migration, proliferation, differentiation, and endothelial cell-cell communication that ultimately lead to the microvessel formation. Since VEGF has a key role during angiogenesis; it may be considered as a good therapeutic target in the clinic. The essential function of several angiogenic factors involved in coronary angiogenesis and intraplaque angiogenesis in atherosclerosis are carefully considered along with the use of angiogenic factors in clinical practice.

Posttraumatic Stress Disorder as a Catalyst for the Association Between Metabolic Syndrome and Reduced Cortical Thickness

BACKGROUND

Metabolic syndrome (MetS), defined by a constellation of cardiometabolic pathologies, is highly prevalent among veterans, especially veterans with posttraumatic stress disorder (PTSD), and poses a major risk for adverse health outcomes, including neurodegeneration and mortality. Given this, we evaluated 1) the association between MetS and neural integrity, indexed by cortical thickness; 2) the relationship between PTSD and MetS; and 3) whether PTSD was associated with cortical thickness indirectly through MetS.

METHODS

The sample consisted of 346 U.S. military veterans (89.3% male; 71.4% white) who deployed to Iraq, Afghanistan, or both. Neuroimaging data were available for 274 participants.

RESULTS

In whole-brain analyses, MetS was negatively associated with cortical thickness in two left and four right hemisphere regions, as follows: bilateral temporal lobe, including temporal pole, fusiform gyrus, and insula, and extending into occipital cortex (left hemisphere) and orbitofrontal cortex (right hemisphere); bilateral precuneus, posterior cingulate, calcarine, and occipital-parietal cortex; and right rostral anterior cingulate cortex and central sulcus/postcentral gyrus. Path models showed that PTSD predicted MetS (β = .19, p < .001), which was associated with reduced cortical thickness (β = -.29 to -.43, all p < .001).

CONCLUSIONS

Results from this young veteran sample provide evidence that PTSD confers risk for cardiometabolic pathology and neurodegeneration and raise concern that this cohort may be aging prematurely and at risk for substantial medical and cognitive decline. This study highlights the need to identify the molecular mechanisms linking PTSD to MetS and effective interventions to reduce PTSD-related health comorbidities.

Influence of cigarette smoking on cardiac biomarkers: the Atherosclerosis Risk in Communities (ARIC) Study

AIMS

Cigarette smoking has been associated with incident heart failure independent of coronary artery disease (CAD), but the mechanisms linking smoking to cardiac damage are not well understood. This study sought to evaluate the relationship between smoking and N-terminal pro-brain natriuretic peptide (NT-proBNP) and high-sensitivity Troponin T (hs-TnT), which are, respectively, biomarkers of myocardial wall stress and injury, in a large community-based cohort.

METHODS AND RESULTS

We examined the association between smoking history and NT-proBNP and hs-TnT in 9649 participants free of overt CAD or heart failure from the Atherosclerosis Risk in Communities (ARIC) Study who attended Visit 4 (1996-1998), as well as the association with change in these biomarkers from Visit 4 to Visit 5 (2011-2013) in 3151 participants. At Visit 4, higher cumulative cigarette exposure, assessed by total pack-years, was associated with elevated levels of NT-proBNP (P < 0.001) and hs-TnT (P = 0.01) among ever smokers in multivariable analyses adjusted for potential confounders. After 15 years of follow-up, participants who were active smokers at Visit 4 had greater incidence of elevated NT-proBNP {adjusted proportion = 48% [95% confidence interval (CI) 41, 54] vs. 35 (95% CI 32, 39); P = 0.006} and hs-TnT [adjusted proportion = 32% (95% CI 26, 38) vs. 23 (95% CI 20, 26); P = 0.021] compared with never smokers, adjusting for baseline and follow-up covariates.

CONCLUSIONS

In a large community-based cohort free of overt CAD and heart failure, cigarette smoking was associated with biomarkers of myocardial wall stress and injury at baseline as well as with a continued measurable increase in these biomarkers after 15 years of follow-up.

Biomarkers of Metabolic Syndrome: Biochemical Background and Clinical Significance

Biomarkers of the metabolic syndrome are divided into four subgroups. Although dividing them in groups has some limitations, it can be used to draw some conclusions. In a first part, the dyslipidemias and markers of oxidative stress are discussed, while inflammatory markers and cardiometabolic biomarkers are reviewed in a second part. For most of them, the biochemical background and clinical significance are discussed, although here also a well-cut separation cannot always be made. Altered levels cannot always be claimed as the cause, risk, or consequence of the syndrome. Several factors are interrelated to each other and act in a concerted, antagonistic, synergistic, or modulating way. Most important conclusions are summarized at the end of every reviewed subgroup. Genetic biomarkers or influences of various food components on concentration levels are not included in this review article.

Association between the polymorphisms of the vascular endothelial growth factor gene and metabolic syndrome

Vascular endothelial growth factor (VEGF) is a major angiogenic factor. Increased levels of VEGF have been reported in patients with metabolic syndrome (MetS). The role of VEGF polymorphisms in MetS susceptibility, however, has not been reported previously. Thus, the present study was performed to analyze the associations between the VEGF -634G>C and 936C>T polymorphisms and the patients with MetS. A total of 320 patients with MetS (mean age, 49.86±11.76 years) and 320 healthy subjects (mean age, 50.94±8.43 years) were enrolled in the study. The VEGF -634G>C polymorphism in the 5'-untranslated region (UTR) and 936C>T polymorphism in 3'-UTR were analyzed by polymerase chain reaction-restriction fragment length polymorphism. The VEGF -634G>C polymorphism significantly affected MetS susceptibility. The CC genotype of the -634G>C polymorphism was significantly associated with an increased risk of MetS [adjusted odds ratio (AOR)=3.973; 95% confidence interval (CI), 2.321-6.799; P<0.0001]. AORs of the dominant (GG vs. GC+CC) and recessive models (GG+GC vs. CC) between the cases and controls were 2.569 (95% CI, 1.657-3.983; P<0.0001) and 2.163 (95% CI, 1.475-3.171; P=0.0001), respectively. Haplotypes of -634G>C and 936C>T were also associated with MetS susceptibility. When the haplotype data were stratified by gender, the association remained only in males. The -634G>C polymorphism was also associated with the subgroups of MetS risk components by the stratification analysis. The 936C>T polymorphism was, however, not associated with the MetS susceptibility. The present study demonstrates that the VEGF -634G>C polymorphism and haplotypes may be a genetic determinant for the MetS susceptibility. To the best of our knowledge, this is the first study on the significant association of the VEGF polymorphisms in MetS patients. To confirm the effects of the VEGF polymorphisms on MetS, further functional and population studies are required.

The relationship between adiponectin and left ventricular mass index varies with the risk of left ventricular hypertrophy

BACKGROUND

Adiponectin directly protects against cardiac remodeling. Despite this beneficial effect, most epidemiological studies have reported a negative relationship between adiponectin level and left ventricular mass index (LVMI). However, a positive relationship has also been reported in subjects at high risk of left ventricular hypertrophy (LVH). Based on these conflicting results, we hypothesized that the relationship between serum adiponectin level and LVMI varies with the risk of LVH.

METHODS

A community-based, cross-sectional study was performed on 1414 subjects. LVMI was measured by echocardiography. Log-transformed adiponectin levels (Log-ADPN) were used for the analysis.

RESULTS

Serum adiponectin level had a biphasic distribution (an increase after a decrease) with increasing LVMI. Although Log-ADPN did not correlate with LVMI, Log-ADPN was modestly associated with LVMI in the multivariate analysis (β = 0.079, p = 0.001). The relationship between adiponectin level and LVMI was bidirectional according to the risk of LVH. In normotensive subjects younger than 50 years, Log-ADPN negatively correlated with LVMI (r = -0.204, p = 0.005); however, Log-ADPN positively correlated with LVMI in ≥50-year-old obese subjects with high arterial stiffness (r = 0.189, p = 0.030). The correlation coefficient between Log-ADPN and LVMI gradually changed from negative to positive with increasing risk factors for LVH. The risk of LVH significantly interacted with the relationship between Log-ADPN and LVMI. In the multivariate analysis, Log-ADPN was associated with LVMI in the subjects at risk of LVH; however, Log-ADPN was either not associated or negatively associated with LVMI in subjects at low risk of LVH.

CONCLUSION

Adiponectin level and LVMI are negatively associated in subjects at low risk of LVH and are positively associated in subjects at high risk of LVH. Therefore, the relationship between adiponectin and LVMI varies with the risk of LVH.

Circulating biomarkers

Cardiovascular diseases (CVD) remain a leading cause of death worldwide. In the past years new biomarkers have drawn the clinician's attention for their use in primary prevention and in the identification of individuals at cardiovascular risk. Biomarkers also provide information on the progression and possible recurrence of cardiovascular events, and include inflammatory markers (C-reactive protein and interleukin-18), endothelial dysfunction markers (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1), neurohormonal markers (brain natriuretic peptide and copeptine), ischemia biomarkers (apolipoprotein J) and necrosis markers (troponins). Although biomarkers provide utility for predicting cardiovascular risk, the identification and characterization of new biomarkers to achieve increasing diagnosis and prognostic efficiency in CVD prevention is of high clinical interest. In this review we will discuss on recently discovered biomarkers and their clinical applications.

Increased circulating High-Sensitivity Troponin T concentrations in children and adolescents with obesity and the metabolic syndrome: a marker for early cardiac damage?

OBJECTIVE

Childhood obesity is associated with an increased risk for atherosclerosis mediated by the pathogenetic mechanisms that lead to the development of the Metabolic Syndrome (MetS). High-Sensitivity Troponin T (hs-TnT) is a specific marker of ischemic myocardial damage, whereas a minimal elevation of this biomarker has been found in adults with a high-risk for cardiovascular disease. We hypothesized that hs-TnT might be altered in obese children with and/or without the Mets.

MATERIALS AND METHODS

Fifty-seven (34 males) obese and 25 non-obese (6 males) children were assessed at the Childhood Obesity Clinic of our department. Obesity was defined using the IOTF criteria. Metabolic syndrome was defined with the IDF criteria. Hs-TnT was measured using an electrochemiluminescence-based assay.

RESULTS

The entire group of obese children had significantly higher hs-TnT concentrations [4.1 ± 3.4 ng/L] (p=0.029) than the non-obese ones [3.0 ± 0.2 ng/L), however, in both groups the levels of the cardiac biomarker were within the normal range. Comparison of the obese children with or without the MetS and the non-obese, revealed that those with the MetS had significantly higher hs-TnT (6.7±7.1 ng/L) than the obese without MetS (3.7 ± 2.1 ng/L) [p=0.044], and the non-obese [p=0.014]. Hs-TnT did not differ between the obese without MetS and the non-obese.

CONCLUSIONS

Circulating concentrations of hs-TnT in obese children with the MetS are higher than those of the obese without the MetS and the non-obese, suggesting that it is obesity-related metabolic changes rather than obesity per se linked to increased hs-TnT in children.

Disruption of components of vascular endothelial growth factor angiogenic signalling system in metabolic syndrome. Findings from a study conducted in rural Bangladeshi women

Metabolic syndrome (MetS) is associated with impaired angiogenesis, a process that is chiefly regulated by vascular endothelial growth factor (VEGF) upon binding to its specific receptors, VEGF-R1 and VEGF-R2. The purpose of the present study was to assess trends or patterns in plasma levels of VEGF and its soluble receptors in subjects with (MetS) or without (non-MetS) MetS; and further examine their association with clinical or metabolic parameters using a subpopulation of South Asian country. A total of 1,802 rural Bangladeshi women aged ≥15 years were studied using a population-based cross-sectional survey. Plasma levels of VEGF were found to be significantly increased (MetS vs. non-MetS: 483.9 vs. 386.9, p<0.001), whereas, the soluble forms of VEGF receptors, sVEGF-R1 and sVEGF-R2, were significantly decreased in subjects with Mets (sVEGF-R1, MetS vs. non-MetS: 512.5 vs. 631.3, p<0.001; sVEGF-R2, MetS vs. non-MetS: 9,302.8 vs. 9,787.4, p=0.004). After adjustment for age and all potential variables, multiple regression analysis revealed that plasma levels of VEGF had significant positive association with blood glucose (p = 0.019) and body mass index (p = 0.007). We also found that mean plasma levels of VEGF increased in direct proportion to levels of MetS components. The present study is the first ever to demonstrate a positive association between trends in levels of plasma VEGF and MetS using a large sample size from South Asia. The association between plasma VEGF and MetS needs further investigations in order to clearly decipher the clinical predictive value and accuracy of plasma VEGF in MetS.

VEGF is indirectly associated with NO production and acutely increases in response to hyperglycaemia(1)

BACKGROUND

Increased levels of vascular endothelial growth factor (VEGF) have been observed in patients with metabolic syndrome (MetS). Nitric oxide (NO) formation is reduced in MetS, but its relationship to VEGF production remains poorly defined. We evaluated the association between VEGF/NO synthesis and insulin sensitivity in obese subjects and investigated the secretory response of VEGF to an acute elevation of glucose.

MATERIALS AND METHODS

Seven healthy normal-weight subjects, seven obese subjects without MetS and seven obese subjects with MetS were recruited. Anthropometry, body composition and cardiometabolic functions (blood pressure, glucose, insulin, triglycerides, total cholesterol, HDL-C and VEGF) were measured, and a novel stable isotope method was used to assess in vivo rates of NO production. A frequent sampling intravenous glucose tolerance test was performed to study the dynamics of VEGF release.

RESULTS

Fasting VEGF levels were significantly higher in the two obese groups compared to the control group (P for trend = 0·02), but the difference was not significant after adjustment for age. Vascular endothelial growth factor levels were associated with systolic blood pressure (ρ = 0·54; P = 0·01) and NO production (ρ = -0·44; P = 0·04). Vascular endothelial growth factor levels increased in response to acute hyperglycaemia in normal-weight and obese subjects (P < 0·001).

CONCLUSIONS

Vascular endothelial growth factor levels rapidly increase during hyperglycaemia and are inversely related to NO production at steady state. The potential link between the acute secretion of VEGF and atherosclerotic risk in subjects with poorly controlled glycaemia as well as the potential of lowering elevated VEGF levels by increasing NO production and/or availability warrants further investigation.

Genetic and environmental factors influencing the Placental Growth Factor (PGF) variation in two populations

Placental Growth Factor (PGF) is a key molecule in angiogenesis. Several studies have revealed an important role of PGF primarily in pathological conditions (e.g.: ischaemia, tumour formation, cardiovascular diseases and inflammatory processes) suggesting its use as a potential therapeutic agent. However, to date, no information is available regarding the genetics of PGF variability. Furthermore, even though the effect of environmental factors (e.g.: cigarette smoking) on angiogenesis has been explored, no data on the influence of these factors on PGF levels have been reported so far. Here we have first investigated PGF variability in two cohorts focusing on non-genetic risk factors: a study sample from two isolated villages in the Cilento region, South Italy (N=871) and a replication sample from the general Danish population (N=1,812). A significant difference in PGF mean levels was found between the two cohorts. However, in both samples, we observed a strong correlation of PGF levels with ageing and sex, men displaying PGF levels significantly higher than women. Interestingly, smoking was also found to influence the trait in the two populations, although differently. We have then focused on genetic risk factors. The association between five single nucleotide polymorphisms (SNPs) located in the PGF gene and the plasma levels of the protein was investigated. Two polymorphisms (rs11850328 and rs2268614) were associated with the PGF plasma levels in the Cilento sample and these associations were strongly replicated in the Danish sample. These results, for the first time, support the hypothesis of the presence of genetic and environmental factors influencing PGF plasma variability.

PlGF: a multitasking cytokine with disease-restricted activity

Placental growth factor (PlGF) is a member of the vascular endothelial growth factor (VEGF) family that also comprises VEGF-A (VEGF), VEGF-B, VEGF-C, and VEGF-D. Unlike VEGF, PlGF is dispensable for development and health but has diverse nonredundant roles in tissue ischemia, malignancy, inflammation, and multiple other diseases. Genetic and pharmacological gain-of-function and loss-of-function studies have identified molecular mechanisms of this multitasking cytokine and characterized the therapeutic potential of delivering or blocking PlGF for various disorders.

Genetics of VEGF serum variation in human isolated populations of cilento: importance of VEGF polymorphisms

Vascular Endothelial Growth Factor (VEGF) is the main player in angiogenesis. Because of its crucial role in this process, the study of the genetic factors controlling VEGF variability may be of particular interest for many angiogenesis-associated diseases. Although some polymorphisms in the VEGF gene have been associated with a susceptibility to several disorders, no genome-wide search on VEGF serum levels has been reported so far. We carried out a genome-wide linkage analysis in three isolated populations and we detected a strong linkage between VEGF serum levels and the 6p21.1 VEGF region in all samples. A new locus on chromosome 3p26.3 significantly linked to VEGF serum levels was also detected in a combined population sample. A sequencing of the gene followed by an association study identified three common single nucleotide polymorphisms (SNPs) influencing VEGF serum levels in one population (Campora), two already reported in the literature (rs3025039, rs25648) and one new signal (rs3025020). A fourth SNP (rs41282644) was found to affect VEGF serum levels in another population (Cardile). All the identified SNPs contribute to the related population linkages (35% of the linkage explained in Campora and 15% in Cardile). Interestingly, none of the SNPs influencing VEGF serum levels in one population was found to be associated in the two other populations. These results allow us to exclude the hypothesis that the common variants located in the exons, intron-exon junctions, promoter and regulative regions of the VEGF gene may have a causal effect on the VEGF variation. The data support the alternative hypothesis of a multiple rare variant model, possibly consisting in distinct variants in different populations, influencing VEGF serum levels.