Vascular endothelial growth factor, its soluble receptor, and hepatocyte growth factor: clinical and genetic correlates and association with vascular function

Challenges and advances in materials and fabrication technologies of small-diameter vascular grafts

The arterial occlusive disease is one of the leading causes of cardiovascular diseases, often requiring revascularization. Lack of suitable small-diameter vascular grafts (SDVGs), infection, thrombosis, and intimal hyperplasia associated with synthetic vascular grafts lead to a low success rate of SDVGs (< 6 mm) transplantation in the clinical treatment of cardiovascular diseases. The development of fabrication technology along with vascular tissue engineering and regenerative medicine technology allows biological tissue-engineered vascular grafts to become living grafts, which can integrate, remodel, and repair the host vessels as well as respond to the surrounding mechanical and biochemical stimuli. Hence, they potentially alleviate the shortage of existing vascular grafts. This paper evaluates the current advanced fabrication technologies for SDVGs, including electrospinning, molding, 3D printing, decellularization, and so on. Various characteristics of synthetic polymers and surface modification methods are also introduced. In addition, it also provides interdisciplinary insights into the future of small-diameter prostheses and discusses vital factors and perspectives for developing such prostheses in clinical applications. We propose that the performance of SDVGs can be improved by integrating various technologies in the near future.

Endocrine responses of the stress system to different types of exercise

Physical activity is an important part of human lifestyle although a large percentage of the population remains sedentary. Exercise represents a stress paradigm in which many regulatory endocrine systems are involved to achieve homeostasis. These endocrine adaptive responses may be either beneficial or harmful in case they exceed a certain threshold. The aim of this review is to examine the adaptive endocrine responses of hypothalamic-pituitary-adrenal axis (HPA), catecholamines, cytokines, growth hormone (GH) and prolactin (PRL) to a single bout or regular exercise of three distinct types of exercise, namely endurance, high-intensity interval (HIIE) and resistance exercise. In summary, a single bout of endurance exercise induces cortisol increase, while regular endurance exercise-induced activation of the HPA axis results to relatively increased basal cortisolemia; single bout or regular exercise induce similar GH peak responses; regular HIIE training lowers basal cortisol concentrations, while catecholamine response is reduced in regular HIIE compared with a single bout of HIIE. HPA axis response to resistance exercise depends on the intensity and volume of the exercise. A single bout of resistance exercise is characterized by mild HPA axis stimulation while regular resistance training in elderly results in attenuated inflammatory response and decreased resting cytokine concentrations. In conclusion, it is important to consider which type of exercise and what threshold is suitable for different target groups of exercising people. This approach intends to suggest types of exercise appropriate for different target groups in health and disease and subsequently to introduce them as medical prescription models.

Angiopoietin-2 predicts all-cause mortality in male but not female end-stage kidney disease patients on hemodialysis

Background

Angiopoietin-2 (Ang-2) plays a pivotal role in pathological vascular remodeling and angiogenesis. Both vascular mechanisms are active in patients with end-stage renal disease (ESRD) and may contribute to the high mortality in these patients. The aim of this multicenter prospective cohort study was to investigate baseline serum Ang-2 concentrations in ESRD patients on hemodialysis (HD) for their ability to predict all-cause mortality.

Methods

We conducted a prospective cohort study in 340 stable HD patients from different chronic dialysis centers in Berlin, Germany. The primary endpoint was all-cause mortality during a 5-year follow-up period. Blood samples and clinical data were collected at baseline. Serum Ang-2 was measured with a validated enzyme-linked immunosorbent assay (Biomedica, Vienna, Austria).

Results

A total of 313 HD patients (206 men and 107 women) were finally included in the study. Receiver operating characteristic (ROC) analysis of Ang-2 concentrations yielded an area under the curve (AUC) of 0.65 (P < 0.0001) for predicting all-cause mortality in the entire study population and was used to determine the optimal cut-off (111.0 pmol/L) for all-cause mortality. Kaplan–Meier survival analysis indicated that male but not female end-stage kidney disease patients on HD with higher Ang-2 concentrations had a significantly lower survival (log-rank test, P < 0.0001 and P = 0.380 for male and female patients, respectively). Multivariable Cox regression analyses adjusted for age, comorbidity, smoking, dialysis vintage, serum creatinine, hemoglobin, C-reactive protein, serum albumin, intact parathyroid hormone (iPTH), low-density lipoprotein (LDL) and Kt/V likewise indicated that elevated Ang-2 concentrations are associated with all-cause mortality in male {hazard ratio [HR] 3.294 [95% confidence interval (CI) 1.768–6.138]; P = 0.0002} but not in female end-stage kidney disease patients on HD [HR 1.084 (95% CI 0.476–2.467); P = 0.847].

Conclusion

Ang-2 at baseline is independently associated with all-cause mortality in male ESRD patients on HD.

Determining the Intracortical Responses After a Single Session of Aerobic Exercise in Young Healthy Individuals: A Systematic Review and Best Evidence Synthesis

ABSTRACT

Alibazi, RJ, Pearce, AJ, Rostami, M, Frazer, AK, Brownstein, C, and Kidgell, DJ. Determining the intracortical responses after a single session of aerobic exercise in young healthy individuals: a systematic review and best evidence synthesis. J Strength Cond Res 35(2): 562-575, 2021-A single bout of aerobic exercise (AE) may induce changes in the excitability of the intracortical circuits of the primary motor cortex (M1). Similar to noninvasive brain stimulation techniques, such as transcranial direct current stimulation, AE could be used as a priming technique to facilitate motor learning. This review examined the effect of AE on modulating intracortical excitability and inhibition in human subjects. A systematic review, according to PRISMA guidelines, identified studies by database searching, hand searching, and citation tracking between inception and the last week of February 2020. Methodological quality of included studies was determined using the Downs and Black quality index and Cochrane Collaboration of risk of bias tool. Data were synthesized and analyzed using best-evidence synthesis. There was strong evidence for AE not to change corticospinal excitability and conflicting evidence for increasing intracortical facilitation and reducing silent period and long-interval cortical inhibition. Aerobic exercise did reduce short-interval cortical inhibition, which suggests AE modulates the excitability of the short-latency inhibitory circuits within the M1; however, given the small number of included studies, it remains unclear how AE affects all circuits. In light of the above, AE may have important implications during periods of rehabilitation, whereby priming AE could be used to facilitate motor learning.

Quantile-specific heritability of serum growth factor concentrations

BACKGROUND

"Quantile-dependent expressivity" occurs when the effect size of a genetic variant depends upon whether the phenotype (e.g. growth factor concentration) is high or low relative to its distribution.

METHODS

Quantile-regression analysis was applied to family sets from the Framingham Heart Study to determine whether the heritability (h²) of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), angiopoietin-2, and angiopoietin-2 (sTie-2) and VEGFR1 (sFlt-1) receptor concentrations were quantile-specific.

RESULTS

Quantile-specific h² (±SE) increased with increasing percentiles of the age- and sex-adjusted VEGF (P_trend<10^-16), HGF (P_trend=0.0004), angiopoietin-2 (P_trend=0.0002), sTie-2 (P_trend=1.2 × 10^-5), and sFlt-1 distributions (P_trend=0.04).

CONCLUSION

Heritabilities of VEGF, HGF, angiopoitein-2, sTie-2 and sFlt-1 concentrations are quantile dependent. This may explain reported interactions of genetic loci (rs10738760, rs9472159, rs833061, rs3025039, rs2280789, rs1570360, rs2010963) with metabolic syndrome, diet, recurrent miscarriage, hepatocellular carcinoma, erysipelas, diabetic retinopathy, and bevacizumab treatment in their effect on VEGF concentrations.

Serum vascular endothelial growth factor as a biomarker for prognosis of minor ischemic stroke

Objectives Although vascular endothelial growth factor (VEGF) is a well-known molecule involved with neuronal survival and angiogenesis. there are no prospective studies directed at evaluating a potential association between serum VEGF and minor ischemic stroke. The goal of this study was to investigate the utility of serum VEGF as an index for assessing the 90-day prognosis of minor ischemic stroke patients. Methods Records of acute minor stroke patients (N = 225) and those of age- and gender-matched healthy control subjects (N = 225) were prospectively reviewed. Clinical, laboratory, and imaging data were evaluated. Serum samples collected from these stroke patients immediately after admission were assessed for VEGF levels and compared with those of control subjects. Results Serum VEGF levels were significantly increased in stroke patients (40.01 ± 16.48 pg/mL) as compared with those of controls (32.98 ± 10.35 pg/mL). No statistically significant differences in serum VEGF levels were obtained among the three stroke subtypes analyzed in this study (large-artery atherosclerosis, small-artery occlusion and other types of brain infarction). Multivariate regression analysis revealed that serum VEGF levels and cerebral artery stenosis ≥ 50 % were independently associated with an unfavorable outcome. Unfavorable outcome rates were significantly greater in stroke patients showing VEGF levels in the upper quartiles of the distribution, and these VEGF levels were found to serve as a significant predictor of unfavorable outcomes in these minor ischemic stroke patients. Conclusion Increased serum VEGF may serve as an independent predictor of an unfavorable outcome in minor ischemic stroke.

Increased hepatocyte growth factor levels over 2 years are associated with coronary heart disease: the Multi-Ethnic Study of Atherosclerosis (MESA)

Hepatocyte growth factor (HGF) is associated with subclinical and clinical atherosclerosis. However, the significance of change in HGF and development of atherosclerotic disease is unknown. In a large and diverse population-based cohort, we report that change in the biomarker HGF is an independent predictor of incident CHD.

Genetic variation determines VEGF-A plasma levels in cancer patients

Angiogenesis is essential in tumor biology and is regulated by vascular endothelial growth factor (VEGF) ligands and receptors. Here we aimed to discover genetic variants associated with levels of circulating angiogenic proteins in cancer patients. Plasma was collected at baseline in 216 pancreatic and 114 colorectal cancer patients. Thirty-one angiogenic proteins were measured by ELISA. 484,523 Single Nucleotide Polymorphisms (SNP) were tested for association with plasma levels for each protein in pancreatic cancer patients. Three top-ranked hits were then genotyped in colorectal cancer patients, where associations with the same proteins were measured. The results demonstrated rs2284284 and MCP1 (P-value = 6.7e–08), rs7504372 and VEGF-C (P-value = 9.8e–09), and rs7767396 and VEGF-A (P-value = 5.8e–09) were SNP-protein pairs identified in pancreatic cancer patients. In colorectal cancer patients, only rs7767396 (A > G) and VEGF-A was validated (P-value = 5.18e–05). The AA genotype of rs7767396 exhibited 2.04–2.3 and 2.7–3.4-fold higher VEGF-A levels than those with AG and GG genotypes. The G allele of rs7767396 reduces binding of the NF-AT1 transcription factor. In conclusion, a common genetic variant predicts the plasma levels of VEGF-A in cancer patients through altered binding of NF-AT1.

Circulating Vascular Growth Factors and Magnetic Resonance Imaging Markers of Small Vessel Disease and Atrophy in Middle-Aged Adults

Background and Purpose- Little is known about associations between vascular growth factors and magnetic resonance imaging (MRI) markers in midlife. We investigated the association of serum VEGF (vascular endothelial growth factor), Ang2 (angiopoietin 2), sTie2 (soluble tyrosine kinase with immunoglobulin-like and EGF-like domains 2), and HGF (hepatocyte growth factor) concentrations with MRI markers of brain aging in middle-aged adults. Methods- We evaluated 1853 participants (mean age, 46±9 years; 46% men) from the Framingham Heart Study. Serum growth factor concentrations were measured using standardized immunoassays. Outcomes included total brain, cortical and subcortical gray matter, white matter, cerebrospinal fluid, and white matter hyperintensity volumes derived from MRI; as well as fractional anisotropy in white matter tracts from diffusion tensor imaging. We related VEGF, Ang2, sTie2, and HGF to MRI measures using multivariable regression models adjusting for vascular risk factors. We tested for interactions with APOE (apolipoprotein E) genotype and CRP (C-reactive protein). Results were corrected for multiple comparisons. Results- Higher sTie2 was associated with smaller total brain (estimate by SD unit±SE=-0.08±0.02, P=0.002) and larger white matter hyperintensity (0.08±0.02, P=0.002) volumes. Furthermore, higher Ang2 (0.06±0.02, P=0.049) and HGF (0.09±0.02, P=0.001) were associated with larger cerebrospinal fluid volumes. Finally, higher Ang2 was associated with decreased fractional anisotropy, in APOE-ε4 carriers only. Conclusions- Vascular growth factors are associated with early MRI markers of small vessel disease and neurodegeneration in middle-aged adults.

The Relationship Between Vascular Endothelial Growth Factor Cis- and Trans-Acting Genetic Variants and Metabolic Syndrome

BACKGROUND

We have investigated the association between 4 cis- and trans-genetic variants (rs6921438, rs4416670, rs6993770 and rs10738760) of the vascular endothelial growth factor (VEGF) gene and metabolic syndrome (MetS) and its individual components in an Iranian population.

MATERIAL & METHOD

Three hundred and thirty-six subjects were enrolled and MetS was defined according to the International-Diabetes-Federation (IDF) criteria. Genotyping was carried out in all the individuals for 4 VEGF genetic variants using an assay based on a combination of multiplex polymerase chain reaction and biochip array hybridization.

RESULTS

As may be expected, patients with MetS had significantly higher levels of serum high-sensitivity C-reactive protein, waist circumference, hip circumference, body mass index, fat percentage, systolic blood pressure, diastolic blood pressure and triglyceride, whereas the high-density lipoprotein cholesterol levels were significantly lower, compared to the control group (P < 0.05). We also found that 1 of the VEGF- level associated genetic variants, rs6993770, was associated with the presence of MetS; the less common T allele at this locus was associated with an increased risk for MetS. This association remained significant after adjustment for confounding factors (P = 0.007). Individuals with MetS carrying the AT + TT genotypes had markedly higher levels of fasting blood glucose, triglyceride and systolic blood pressure (P < 0.05).

CONCLUSIONS

We have found an association between the rs6993770 polymorphism and MetS. This gene variant was also associated with serum VEGF concentrations. There was also an association between this variant and the individual components of the MetS, including triglyceride, fasting blood glucose and systolic blood pressure.

Serum Vascular Endothelial Growth Factor Levels in the IVAN Trial; Relationships with Drug, Dosing, and Systemic Serious Adverse Events

Purpose

To describe serum vascular endothelial growth factor (sVEGF) in patients with neovascular age-related macular degeneration (nAMD) receiving anti-VEGF agents and associations between sVEGF and systemic serious adverse events (SSAEs).

Design

Exploratory analyses of a randomized controlled trial that enrolled 610 participants with nAMD and compared 2 anti-VEGF antibodies, ranibizumab and bevacizumab, and 2 treatment regimens, monthly vs. discontinuous, with 2 years' follow-up.

Participants

Adults aged 50+ years with treatment-naïve nAMD and a visual acuity of ≥25 letters (Snellen equivalent 20/320) in the affected eye.

Methods

Intravitreal injection of anti-VEGF antibodies.

Main Outcome Measures

sVEGF and occurrence of SSAE, with particular interest in arteriothromboembolic events (ATE) and immunologically mediated events (IME).

Results

On average, sVEGF (measured at months 0, 1, 11, 12, 23, and 24) decreased from a geometric mean of 168 pg/mL at baseline to 64 pg/mL at month 24. The decrease was greater with bevacizumab than with ranibizumab and was dependent on time since last treatment; at month 24 sVEGF was 11% lower with bevacizumab if treated ≥3 months previously, 51% lower if treated 2 months previously, and 76% lower if treated the previous month, compared with ranibizumab. The hazard of experiencing an ATE increased with age (hazard ratio [HR] = 2.01; 95% confidence interval [CI] = 1.32–3.05; P = 0.001) and higher sVEGF (HR = 1.16; 95% CI = 1.03–1.30, per 100 unit rise in sVEGF; P = 0.013). There was no association between sVEGF and the hazard of an IME (HR = 1.01; 95% CI = 0.76–1.33; P = 0.942); however, the hazard of an IME was significantly increased by treatment with bevacizumab compared with ranibizumab (HR = 3.53; 95% CI = 1.35–9.22; P = 0.010). The hazard of an “other SSAE” (not categorized as ATE or IME) increased with age (HR 1.51, 95% CI 1.14–2.01, P = 0.005) and decreased if an injection had been administered within the previous month (HR = 0.68; 95% CI = 0.45–1.03; P = 0.069).

Conclusions

The decrease in sVEGF is greater with bevacizumab than with ranibizumab, but this difference is eliminated when treatment is withheld for 3 months. Higher sVEGF increased the hazard of an ATE and bevacizumab increases the hazard of an IME compared with ranibizumab.

Hepatocyte growth factor demonstrates racial heterogeneity as a biomarker for coronary heart disease

OBJECTIVE

To determine if hepatocyte growth factor (HGF), a promising biomarker of coronary heart disease (CHD) given its release into circulation in response to endothelial damage, is associated with subclinical and clinical CHD in a racial/ethnic diverse population.

METHODS

HGF was measured in 6738 participants of the Multi-Ethnic Study of Atherosclerosis (MESA). Highest mean HGF values (pg/mL) were observed in Hispanic, followed by African, non-Hispanic white, then Chinese Americans.

RESULTS

In all races/ethnicities, HGF levels were associated with older age, higher systolic blood pressure (SBP) and body mass index, lower high-density lipoprotein, diabetes and current smoking. In fully adjusted models, each SD higher HGF was associated with an average increase in coronary artery calcium (CAC) of 55 Agatston units for non-Hispanic whites (p<0.001) and 51 Agatston units for African-Americans (p=0.007) but was not in the other race/ethnic groups (interaction p=0.02). There were 529 incident CHD events, and CHD risk was 41% higher in African (p<0.001), 17% in non-Hispanic white (p=0.026) and Chinese (p=0.36), and 6% in Hispanic Americans (p=0.56) per SD increase in HGF.

CONCLUSION

In a large and diverse population-based cohort, we report that HGF is associated with subclinical and incident CHD. We demonstrate evidence of racial/ethnic heterogeneity within these associations, as the results are most compelling in African-Americans and non-Hispanic white Americans. We provide evidence that HGF is a biomarker of atherosclerotic disease that is independent of traditional risk factors.

The effects of Nigella sativa on thyroid function, serum Vascular Endothelial Growth Factor (VEGF) - 1, Nesfatin-1 and anthropometric features in patients with Hashimoto's thyroiditis: a randomized controlled trial

Background

Hashimoto’s thyroiditis is an autoimmune disorder and the most common cause of hypothyroidism. The use of Nigella sativa, a potent herbal medicine, continues to increase worldwide as an alternative treatment of several chronic diseases including hyperlipidemia, hypertension and type 2 diabetes mellitus (T2DM). The aim of the current study was to evaluate the effects of Nigella sativa on thyroid function, serum Vascular Endothelial Growth Factor (VEGF) – 1, Nesfatin-1 and anthropometric features in patients with Hashimoto’s thyroiditis.

Methods

Forty patients with Hashimoto’s thyroiditis, aged between 22 and 50 years old, participated in the trial and were randomly allocated into two groups of intervention and control receiving powdered Nigella sativa or placebo daily for 8 weeks. Changes in anthropometric variables, dietary intakes, thyroid status, serum VEGF and Nesfatin-1 concentrations after 8 weeks were measured.

Results

Treatment with Nigella sativa significantly reduced body weight and body mass index (BMI). Serum concentrations of thyroid stimulating hormone (TSH) and anti-thyroid peroxidase (anti-TPO) antibodies decreased while serum T3 concentrations increased in Nigella sativa-treated group after 8 weeks. There was a significant reduction in serum VEGF concentrations in intervention group. None of these changes had been observed in placebo treated group. In stepwise multiple regression model, changes in waist to hip ratio (WHR) and thyroid hormones were significant predictors of changes in serum VEGF and Nesgfatin-1 values in Nigella sativa treated group (P < 0.05).

Conclusions

Our data showed a potent beneficial effect of powdered Nigella sativa in improving thyroid status and anthropometric variables in patients with Hashimoto’s thyroiditis. Moreover, Nigella sativa significantly reduced serum VEGF concentrations in these patients. Considering observed health- promoting effect of this medicinal plant in ameliorating the disease severity, it can be regarded as a useful therapeutic approach in management of Hashimoto’s thyroiditis.

Trial registration

Iranian registry of clinical trials (registration number IRCT2015021719082N4- Registered March-15-2015).

Hepatocyte Growth Factor Is Positively Associated With Risk of Stroke: The MESA (Multi-Ethnic Study of Atherosclerosis)

BACKGROUND AND PURPOSE

Hepatocyte growth factor (HGF) is positively associated with ischemic and hemorrhagic stroke risk factors. However, understanding the relation between HGF and stroke is in its infancy. Therefore, we sought to examine the association of circulating HGF with incident stroke using data from the MESA (Multi-Ethnic Study of Atherosclerosis). We hypothesized that circulating HGF would be positively associated with an increased risk of stroke.

METHODS

Participants aged 45 to 84 years (n=6711) had HGF measured between 2000 and 2002 and were followed for incident stroke through 2013 (n=233). Cox proportional hazards regression was used to calculate hazard ratios and 95% confidence intervals for incident stroke. A secondary analysis stratified results by adjudicated stroke type (n=183 ischemic; n=39 hemorrhagic; n=11 other).

RESULTS

After adjustment for potential confounding variables, risk of stroke was 17% higher with each standard deviation increase in HGF (hazard ratio, 1.17; 95% confidence interval, 1.03-1.34). This association was mainly driven by ischemic stroke and did not change on exclusion of cardioembolic strokes, although the number of excluded cases was small. The few hemorrhagic and other types of stroke were not associated with HGF.

CONCLUSIONS

Circulating HGF was positively associated with the incidence of stroke in a diverse, population-based cohort of men and women from the United States. Our findings support the hypothesis that circulating HGF is a marker of endothelial damage and suggest that HGF may have utility as a prognostic marker of stroke risk.

Angiopoietin-2, its soluble receptor Tie-2, and metabolic syndrome components in a population-based sample

OBJECTIVE

Since angiopoietin-2 (Ang-2) levels strongly correlate with cardiovascular mortality and subclinical cardiovascular disease, it was hypothesized that levels of Ang-2 and its soluble receptor (sTie-2) were associated with the metabolic syndrome (MetS) and individual MetS components.

METHODS

Within the population-based Study of Health in Pomerania, two sets of analyses were performed. First, Ang-2 and sTie-2 were related to the prevalence of MetS and its components cross-sectionally (n = 3,205). Second, the association between baseline Ang-2 and sTie-2 and incident MetS or longitudinal changes in its components in 1,295 individuals was investigated.

RESULTS

High Ang-2 levels (90th percentile), compared with low Ang-2 levels (10th percentile), were positively associated with MetS (OR: 1.78) and with the following MetS criteria: increased triglycerides, lower HDL cholesterol, and higher non-fasting glucose. Furthermore, high sTie-2 levels (90th percentile), compared with low levels (10th percentile), were positively related to MetS (OR: 1.58) and most of its components. However, Ang-2 and sTie-2 levels were not associated with incident MetS or longitudinal change in components of MetS.

CONCLUSIONS

Ang-2 and sTie-2 levels were cross-sectionally associated with MetS and several of its components. However, Ang-2 and sTie-2 levels were not associated with incident MetS or changes in individual MetS components during follow-up.

Effects of cigarette smoking on cardiovascular-related protein profiles in two community-based cohort studies

BACKGROUND AND AIMS

Cardiovascular diseases account for the largest fraction of smoking-induced deaths. Studies of smoking in relation to cardiovascular-related protein markers can provide novel insights into the biological effects of smoking. We investigated the associations between cigarette smoking and 80 protein markers known to be related to cardiovascular diseases in two community-based cohorts, the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS, n = 969, 50% women, all aged 70 years) and the Uppsala Longitudinal Study of Adult Men (ULSAM, n = 717, all men aged 77 years).

METHODS

Smoking status was self-reported and defined as current smoker, former smoker or never-smoker. Levels of the 80 proteins were measured using the proximity extension assay, a novel PCR-based proteomics technique.

RESULTS

We found 30 proteins to be significantly associated with current cigarette smoking in PIVUS (FDR<5%); and ten were replicated in ULSAM (p < 0.05). Matrix metalloproteinase-12 (MMP-12), growth/differentiation factor 15 (GDF-15), urokinase plasminogen activator surface receptor (uPAR), TNF-related apoptosis-inducing ligand receptor 2 (TRAIL-R2), lectin-like oxidized LDL receptor 1 (LOX-1), hepatocyte growth factor (HGF), matrix metalloproteinase-10 (MMP-10) and matrix metalloproteinase-1 (MMP-1) were positively associated, while endothelial cell-specific molecule 1 (ESM-1) and interleukin-27 subunit alpha (IL27-A) showed inverse associations. All of them remained significant in a subset of individuals without manifest cardiovascular disease.

CONCLUSIONS

The findings of the present study suggest that cigarette smoking may interfere with several essential parts of the atherosclerosis process, as evidenced by associations with protein markers representing endothelial dysfunction, inflammation, neointimal formation, foam cell formation and plaque instability.

Serum levels of Dkk-1, sclerostin and VEGF in patients with ankylosing spondylitis and their association with smoking, and clinical, inflammatory and radiographic parameters

OBJECTIVE

To evaluate serum Dickkopf-1 (Dkk-1), sclerostin and vascular endothelial growth factor (VEGF) levels in patients with ankylosing spondylitis (AS) compared to healthy controls as well as their association with smoking, and clinical, inflammatory and radiographic parameters.

METHODS

Serum samples for total Dkk-1, sclerostin and VEGF were obtained from 57 tumour necrosis factor (TNF) inhibitor naïve patients with AS and 34 sex-, age- and body mass index (BMI)-matched controls. The erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Bath AS Disease Activity Index (BASDAI), Bath AS Functional Index (BASFI), modified Stroke AS Spine Score (mSASSS) and smoking status were assessed for each patient.

RESULTS

There was no significant difference in serum bone metabolism markers between AS patients and controls. Dkk-1 levels were significantly (P<0.05) higher in AS patients with elevated ESR and CRP and no syndesmophytes, and were significantly (P<0.001) correlated with sclerostin levels (r=0.592). VEGF levels were significantly (P<0.05) higher in AS patients with current and ever smoking, elevated ESR and CRP, and high BASDAI and BASFI, and were significantly (P<0.05) correlated with ESR (r=0.284), CRP (r=0.285), BASDAI (r=0.349) and BASFI (r=0.275). In multivariate regression analyses, high Dkk-1 levels were significantly (P≤0.001) associated with elevated ESR and CRP, no syndesmophytes and high sclerostin levels, and high VEGF levels significantly (P<0.05) with ever smoking, and elevated ESR and CRP.

CONCLUSION

In AS, serum Dkk-1 concentrations appear to be related not only to syndesmophyte formation but also to systemic inflammation. Furthermore, high VEGF levels may be associated with smoking exposure.

Circulating vascular endothelial growth factor and the risk of cardiovascular events

OBJECTIVE

To investigate the relation of circulating concentrations of vascular endothelial growth factor (VEGF) for the risk of developing cardiovascular disease (CVD) in a large community-based sample.

METHODS

We prospectively assessed the relation of circulating VEGF concentrations with the incidence of CVD among 3041 Framingham Heart Study participants (mean age 63.4±11.1 years, 59% women). Multivariable Cox proportional hazards models were estimated adjusting for standard risk factors to VEGF quartiles to incident CVD. Restricted cubic splines were used to examine the linearity of the association.

RESULTS

After a mean follow-up of 8.8 (±2.8) years, 527 individuals experienced a first CVD event. Compared with participants in the first VEGF quartile, individuals in the second VEGF quartile had a 34% increased risk for future CVD (HR 1.34, 95% CI 1.03 to 1.74; p value=0.03) and individuals in third quartile had a 59% higher risk (HR 1.59; 95% CI 1.23 to 2.05, p value=0.0003). Individuals in the highest VEGF quartile had a similar cardiovascular risk as compared with those in the lowest VEGF quartile (HR 1.18, 95% CI 0.91 to 1.53, p value=0.21). Evaluation of restricted cubic splines confirmed the nonlinear, inverted U-shaped relation of serum VEGF and CVD events (p<0.0001 for model fit, p=0.006 for non-linearity).

CONCLUSIONS

Circulating VEGF concentrations exhibit a complex non-linear (inverted U-shaped) relation with the risk of developing CVD events, with the lowest risk experienced at the lower and upper end of the distribution. The underlying pathophysiological mechanisms remain to be elucidated.

Six Novel Loci Associated with Circulating VEGF Levels Identified by a Meta-analysis of Genome-Wide Association Studies

Vascular endothelial growth factor (VEGF) is an angiogenic and neurotrophic factor, secreted by endothelial cells, known to impact various physiological and disease processes from cancer to cardiovascular disease and to be pharmacologically modifiable. We sought to identify novel loci associated with circulating VEGF levels through a genome-wide association meta-analysis combining data from European-ancestry individuals and using a dense variant map from 1000 genomes imputation panel. Six discovery cohorts including 13,312 samples were analyzed, followed by in-silico and de-novo replication studies including an additional 2,800 individuals. A total of 10 genome-wide significant variants were identified at 7 loci. Four were novel loci (5q14.3, 10q21.3, 16q24.2 and 18q22.3) and the leading variants at these loci were rs114694170 (MEF2C, P = 6.79x10^-13), rs74506613 (JMJD1C, P = 1.17x10^-19), rs4782371 (ZFPM1, P = 1.59x10^-9) and rs2639990 (ZADH2, P = 1.72x10^-8), respectively. We also identified two new independent variants (rs34528081, VEGFA, P = 1.52x10^-18; rs7043199, VLDLR-AS1, P = 5.12x10^-14) at the 3 previously identified loci and strengthened the evidence for the four previously identified SNPs (rs6921438, LOC100132354, P = 7.39x10^-1467; rs1740073, C6orf223, P = 2.34x10^-17; rs6993770, ZFPM2, P = 2.44x10^-60; rs2375981, KCNV2, P = 1.48x10^-100). These variants collectively explained up to 52% of the VEGF phenotypic variance. We explored biological links between genes in the associated loci using Ingenuity Pathway Analysis that emphasized their roles in embryonic development and function. Gene set enrichment analysis identified the ERK5 pathway as enriched in genes containing VEGF associated variants. eQTL analysis showed, in three of the identified regions, variants acting as both cis and trans eQTLs for multiple genes. Most of these genes, as well as some of those in the associated loci, were involved in platelet biogenesis and functionality, suggesting the importance of this process in regulation of VEGF levels. This work also provided new insights into the involvement of genes implicated in various angiogenesis related pathologies in determining circulating VEGF levels. The understanding of the molecular mechanisms by which the identified genes affect circulating VEGF levels could be important in the development of novel VEGF-related therapies for such diseases.

Vascular Endothelial Growth Factor (VEGF) is a protein with a fundamental role in development of vascular system. The protein, produced by many types of cells, is released in the blood. High levels of VEGF have been observed in different pathological conditions especially in cancer, cardiovascular, and inflammatory diseases. Therefore, identifying the genetic factors influencing VEGF levels is important for predicting and treating such pathologies. The number of genetic variants associated with VEGF levels has been limited. To identify new loci, we have performed a Genome Wide Association Study meta-analysis on a sample of more than 16,000 individuals from 10 cohorts, using a high-density genetic map. This analysis revealed 10 variants associated with VEGF circulating levels, 6 of these being novel associations. The 10 variants cumulatively explain more than 50% of the variability of VEGF serum levels. Our analyses have identified genes known to be involved in angiogenesis related diseases and genes implicated in platelet metabolism, suggesting the importance of links between this process and VEGF regulation. Overall, these data have improved our understanding of the genetic variation underlying circulating VEGF levels. This in turn could guide our response to the challenge posed by various VEGF-related pathologies.

Interleukin-6, interleukin-6 receptor gene variant, small-vessel disease and incident dementia

BACKGROUND AND PURPOSE

Mixed neurogenerative and vascular dementia has emerged as the leading cause of dementia in the elderly. Inflammation is implicated in atherosclerosis, cerebral small-vessel disease (SVD) as well as cognitive impairment. However, longitudinal data on the predictive value of circulating inflammatory markers including gene variants and magnetic resonance imaging (MRI) findings in incident dementia are scarce. It was investigated whether circulating interleukin-6 (IL-6), C-reactive protein (CRP) and gene variants increase dementia risk.

METHODS

In a cohort of Japanese participants with vascular risk factors in an observational study from 2001, the association between baseline IL-6, CRP levels, gene variants [interleukin-6 receptor (IL-6R), rs2228145; IL-6, rs2097677; CRP, rs3093059] and incident all-cause dementia was evaluated. Baseline MRI was used to determine SVD (lacuna, white matter hyperintensities) and atrophy (medial-temporal lobe atrophy, bicaudate ratio). Cox proportional hazards analyses were performed for predictors of dementia, adjusting for age, sex, apolipoprotein Eε4, education, cerebrovascular events, vascular risk factors and MRI findings.

RESULTS

Of 803 subjects (mean 67.0 ± 8.5 years, males 59%), during a mean of 7.5 ± 3.2 years follow-up, 60 incident dementia patients (Alzheimer's disease 31; vascular dementia 17; mixed-type six; other six) were diagnosed. In multivariable analyses adjusted for age, sex, cerebrovascular events, MRI findings and IL-6R variant (rs2228145), IL-6 levels (relative risk 1.68, P = 0.048) or highest tertile (relative risk 2.38, P = 0.031) for all-cause dementia remained significant. Although subjects with rs2228145 carrier had significantly higher IL-6 levels, a significant association between rs2228145 and dementia was not observed. Conversely, CRP and remaining gene variants were not associated with dementia.

CONCLUSIONS

The deleterious effect of higher IL-6 on dementia remains consistent irrespective of conventional risk factors, MRI findings and IL-6R variant.

Identifying Common Genetic Risk Factors of Diabetic Neuropathies

Type 2 diabetes mellitus (T2DM) is a global public health problem of epidemic proportions, with 60-70% of affected individuals suffering from associated neurovascular complications that act on multiple organ systems. The most common and clinically significant neuropathies of T2DM include uremic neuropathy, peripheral neuropathy, and cardiac autonomic neuropathy. These conditions seriously impact an individual's quality of life and significantly increase the risk of morbidity and mortality. Although advances in gene sequencing technologies have identified several genetic variants that may regulate the development and progression of T2DM, little is known about whether or not the variants are involved in disease progression and how these genetic variants are associated with diabetic neuropathy specifically. Significant missing heritability data and complex disease etiologies remain to be explained. This article is the first to provide a review of the genetic risk variants implicated in the diabetic neuropathies and to highlight potential commonalities. We thereby aim to contribute to the creation of a genetic-metabolic model that will help to elucidate the cause of diabetic neuropathies, evaluate a patient's risk profile, and ultimately facilitate preventative and targeted treatment for the individual.

Fat quality and incident cardiovascular disease, all-cause mortality, and cancer mortality

CONTEXT

Cellular characteristics of fat quality have been associated with cardiometabolic risk and can be estimated by computed tomography (CT) attenuation.

OBJECTIVE

The aim was to determine the association between CT attenuation (measured in Hounsfield units [HU]) and clinical outcomes.

METHODS

This was a prospective community-based cohort study using data from the Framingham Heart Study (n = 3324, 48% women, mean age 51 years) and Cox proportional hazard models.

MAIN OUTCOMES

The primary outcomes of interest were incident cardiovascular disease (CVD) and all-cause mortality. The secondary outcomes of interest were incident cancer, non-CVD death, and cancer death.

RESULTS

There were 111 incident CVD events, 137 incident cancers, 85 deaths including 69 non-CVD deaths, and 45 cancer deaths in up to 23 047 person-years of follow-up. A 1-SD increment in visceral adipose tissue (VAT) HU was inversely associated with incident CVD in the age- and sex-adjusted model (hazard ratio [HR] 0.78, P = .02) but not after multivariable adjustment (HR 0.83, P = .11). VAT HU was directly associated with all-cause mortality (multivariable HR 1.40, P = .003), which maintained significance after additional adjustment for body mass index (HR 1.53, P < .001) and VAT volume (HR 1.99, P < .001). Non-CVD death remained significant in all 3 models, including after adjustment for VAT volume (HR 1.97, P < .001). VAT HU was also associated with cancer mortality (HR 1.93, P = .002). Similar results were obtained for sc adipose tissue HU.

CONCLUSIONS

Fat quality, as estimated by CT attenuation, is associated with all-cause mortality, non-CVD death, and cancer death. These associations highlight how indirect indices of fat quality can potentially add to a better understanding of obesity-related complications.

Genome-wide association study for endothelial growth factors

BACKGROUND

Endothelial growth factors including angiopoietin-2 (Ang-2), its soluble receptor Tie-2 (sTie-2), and hepatocyte growth factor play important roles in angiogenesis, vascular remodeling, local tumor growth, and metastatic potential of various cancers. Circulating levels of these biomarkers have a heritable component (between 13% and 56%), but the underlying genetic variation influencing these biomarker levels is largely unknown.

METHODS AND RESULTS

We performed a genome-wide association study for circulating Ang-2, sTie-2, and hepatocyte growth factor in 3571 Framingham Heart Study participants and assessed replication of the top hits for Ang-2 and sTie-2 in 3184 participants of the Study of Health in Pomerania. In multivariable-adjusted models, sTie-2 and hepatocyte growth factor concentrations were associated with single-nucleotide polymorphisms in the genes encoding the respective biomarkers (top P=2.40×10(-65) [rs2273720] and 3.64×10(-19) [rs5745687], respectively). Likewise, rs2442517 in the MCPH1 gene (in which the Ang-2 gene is embedded) was associated with Ang-2 levels (P=5.05×10(-8) in Framingham Heart Study and 8.39×10(-5) in Study of Health in Pomerania). Furthermore, single-nucleotide polymorphisms in the AB0 gene were associated with sTie-2 (top single-nucleotide polymorphism rs8176693 with P=1.84×10(-33) in Framingham Heart Study; P=2.53×10(-30) in Study of Health in Pomerania) and Ang-2 (rs8176746 with P=2.07×10(-8) in Framingham Heart Study; P=0.001 in Study of Health in Pomerania) levels on a genome-wide significant level. The top genetic loci were explained between 1.7% (Ang-2) and 11.2% (sTie-2) of the interindividual variation in biomarker levels.

CONCLUSIONS

Genetic variation contributes to the interindividual variation in growth factor levels and explains a modest proportion of circulating hepatocyte growth factor, Ang-2, and Tie-2. This may potentially contribute to the familial susceptibility to cancer, a premise that warrants further studies.

Effects of Lys-Glu-Trp peptide on cell-cell interactions and vascular endothelium proliferation under normal conditions and during atherosclerosis

The molecular mechanism of atherosclerosis is based on decreased expression of signal molecules connexin (Cx37 and Cx40), vascular endothelial growth factor (VEGF), and proliferative protein Ki-67, which characterize the processes of cell-cell interactions and proliferation of vascular endotheliocytes. Lys-Glu-Trp peptide in doses of 4 and 40 μg/ml promoted recovery of Cx37, Cx40, and VEGF expression in cultured endotheliocytes from the aorta of patients with atherosclerosis, which attests to vasoprotective effects of this agent.

Vascular endothelial growth factor from embryonic status to cardiovascular pathology

Vascular endothelial growth factor (VEGF) is a multifunctional cytokine with distinct functions in angiogenesis, lymphangiogenesis, vascular permeability, and hematopoiesis. VEGF is a highly conserved, disulfide-bonded dimeric glycoprotein of 34 to 45 kDa produced by several cell types including fibroblasts, neutrophils, endothelial cells, and peripheral blood mononuclear cells, particularly T lymphocytes and macrophages. Six VEGF isoforms are generated as a result of alternative splicing from a single VEGF gene, consisting of 121, 145, 165, 183, 189, or 206 amino acids. VEGF121, VEGF145, and VEGF165 are secreted whereas VEGF183, VEGF189, and VEGF206 are cell membrane-bound. VEGF145 has a key role during the vascularization of the human ovarian follicle and corpus luteum, in the placentation and embryonic periods, and in bone and wound healing, while VEGF165 is the most abundant and biologically active isoform. VEGF has been linked with a number of vascular pathologies including cardiovascular diseases such ischemic heart disease, heart failure, stroke, and diabetes and its related complications. In this review we aimed to present some important roles of VEGF in a number of clinical issues and indicate its involvement in several phenomena from the initial steps of the embryonic period to cardiovascular diseases.

Circulating angiogenic and inflammatory cytokine responses to acute aerobic exercise in trained and sedentary young men

PURPOSE

Endurance exercise training can ameliorate many cardiovascular and metabolic disorders and attenuate responses to inflammatory stimuli. The purpose of this study was to determine whether the angiogenic and pro-inflammatory cytokine response to acute endurance exercise differs between endurance-trained and sedentary young men.

METHODS

Ten endurance-trained and ten sedentary healthy young men performed 30 min of treadmill running at 75 % VO2max with blood sampling before and after exercise. Plasma concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-8, IL-6, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), placental growth factor (PlGF), and soluble VEGF receptor-1 (sFlt-1) were measured by multiplex ELISA.

RESULTS

Acute exercise increased IL-6 by 165 % (P < 0.05), IL-8 by 32 % (P < 0.05), PlGF by ~16 % (P < 0.05), sFlt-1 by 36 % (P < 0.001), and tended to increase bFGF by ~25 % (P = 0.06) in main effects analyses. TNF-α and VEGF did not change significantly with exercise in either group. Contrary to our hypothesis, there were no significant differences in TNF-α, IL-6, VEGF, bFGF, PlGF, or sFlt-1 between groups before or after acute exercise; however, there was a tendency for IL-8 concentrations to be higher in endurance-trained subjects compared to sedentary subjects (P = 0.06).

CONCLUSIONS

These results indicate that 30 min of treadmill running at 75 % VO2max produces a systemic angiogenic and inflammatory reaction, but endurance exercise training does not appear to significantly alter these responses in healthy young men.

Serum brain-derived neurotrophic factor and vascular endothelial growth factor levels are associated with risk of stroke and vascular brain injury: Framingham Study

BACKGROUND AND PURPOSE

Brain-derived neurotrophic factor (BDNF), a major neurotrophin and vascular endothelial growth factor (VEGF) have a documented role in neurogenesis, angiogenesis, and neuronal survival. In animal experiments, they impact infarct size and functional motor recovery after an ischemic brain lesion. We sought to examine the association of serum BDNF and VEGF with the risk of clinical stroke or subclinical vascular brain injury in a community-based sample.

METHODS

In 3440 Framingham Study participants (mean age, 65±11 years; 56% women) who were free of stroke/transient ischemic attack (TIA), we related baseline BDNF and logVEGF to risk of incident stroke/TIA. In a subsample with brain MRI and with neuropsychological tests available (n=1863 and 2104, respectively; mean age, 61±9 years, 55% women, in each), we related baseline BDNF and logVEGF to log-white matter hyperintensity volume on brain MRI, and to visuospatial memory and executive function tests.

RESULTS

During a median follow-up of 10 years, 193 participants experienced incident stroke/TIA. In multivariable analyses adjusted for age, sex, and traditional stroke risk factors, lower BDNF and higher logVEGF levels were associated with an increased risk of incident stroke/TIA (hazard ratio comparing BDNF Q1 versus Q2-Q4, 1.47; 95% confidence interval, 1.09-2.00; P=0.012 and hazard ratio/SD increase in logVEGF, 1.21; 95% confidence interval, 1.04-1.40; P=0.012). Persons with higher BDNF levels had less log-white matter hyperintensity volume (β±SE=-0.05±0.02; P=0.025), and better visual memory (β±SE=0.18±0.07; P=0.005).

CONCLUSIONS

Lower serum BDNF and higher VEGF concentrations were associated with increased risk of incident stroke/TIA. Higher levels of BDNF were also associated with less white matter hyperintensity and better visual memory. Our findings suggest that circulating BDNF and VEGF levels modify risk of clinical and subclinical vascular brain injury.

Effects of prior acute exercise on circulating cytokine concentration responses to a high-fat meal

High-fat meal consumption alters the circulating cytokine profile and contributes to cardiometabolic diseases. A prior bout of exercise can ameliorate the triglyceride response to a high-fat meal, but the interactive effects of exercise and high-fat meals on cytokines that mediate cardiometabolic risk are not fully understood. We investigated the effects of prior exercise on the responses of circulating tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-8, leptin, retinol-binding protein 4 (RBP4), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), placental growth factor (PlGF), and soluble fms-like tyrosine kinase-1 (sFlt-1) to a high-fat meal. Ten healthy men were studied before and 4 h after ingestion of a high-fat meal either with or without ∼50 min of endurance exercise at 70% of VO2 max on the preceding day. In response to the high-fat meal, lower leptin and higher VEGF, bFGF, IL-6, and IL-8 concentrations were evident (P < 0.05 for all). There was no effect of the high-fat meal on PlGF, TNF-α, or RBP4 concentrations. We found lower leptin concentrations with prior exercise (P < 0.05) and interactive effects of prior exercise and the high-fat meal on sFlt-1 (P < 0.05). The high-fat meal increased IL-6 by 59% without prior exercise and 218% with prior exercise (P < 0.05). In conclusion, a prior bout of endurance exercise does not affect all high-fat meal-induced changes in circulating cytokines, but does affect fasting or postprandial concentrations of IL-6, leptin, and sFlt-1. These data may reflect a salutary effect of prior exercise on metabolic responses to a high-fat meal.

Insulin infusion reduces hepatocyte growth factor in lean humans

OBJECTIVE

Plasma Hepatocyte Growth Factor (HGF) is significantly elevated in obesity and may contribute to vascular disease, metabolic syndrome or cancer in obese individuals. The current studies were done to determine if hyperinsulinemia increases plasma HGF.

MATERIALS/METHODS

Twenty-two participants (10 women/12 men, BMI 20.6-34.5 kg/m(2), age 18-49 years) underwent a hyperinsulinemic euglycemic clamp with measurement of HGF at baseline and steady state. Relationships between baseline HGF, anthropometrics, triglycerides, liver enzymes, c-reactive protein and adiponectin were also evaluated.

RESULTS

Fasting HGF was positively correlated (P<0.050) with weight (r=0.63), BMI (r=0.55), waist circumference (r=0.68), WHR (r=0.48), triglycerides (r=0.44), alanine aminotransferase (r=0.74) and γ-glutamyl transpeptidase (r=0.56), but not c-reactive protein or adiponectin. In stepwise regression, alanine aminotransferase and insulin sensitivity accounted for significant variation in fasting HGF. A significant effect of insulin to suppress HGF during the clamp (P=0.029) was found after adjustment for BMI. HGF was reduced 7% at steady state in the lean subjects only (437.1 ±57.8 vs 405.4±72.0 pg/ml; P=0.030).

CONCLUSIONS

The positive correlation of HGF with hepatic enzymes suggests liver may be a significant source of circulating HGF in lean subjects. The strong correlation of plasma HGF with adiposity and the lack of an effect of insulin to increase HGF during the clamp in obese subjects suggest that adiposity, rather than elevated insulin levels, may be the major contributor to plasma HGF in obese subjects. Thus, a reduction in plasma HGF through weight loss is likely the best way to decrease comorbidities mediated by this angiogenic and mitogenic factor.

What is the contribution of two genetic variants regulating VEGF levels to type 2 diabetes risk and to microvascular complications?

Vascular endothelial growth factor (VEGF) is a key chemokine involved in tissue growth and organ repair processes, particularly angiogenesis. Elevated circulating VEGF levels are believed to play a role in type 2 diabetes (T2D) microvascular complications, especially diabetic retinopathy. Recently, a genome-wide association study identified two common single nucleotide polymorphisms (SNPs; rs6921438 and rs10738760) explaining nearly half of the variance in circulating VEGF levels. Considering the putative contribution of VEGF to T2D and its complications, we aimed to assess the effect of these VEGF-related SNPs on the risk of T2D, nephropathy and retinopathy, as well as on variation in related traits.SNPs were genotyped in several case-control studies: French and Danish T2D studies (N(cases) = 6,920-N(controls) = 3,875 and N(cases) = 3,561-N(controls) = 2,623; respectively), two French studies one for diabetic nephropathy (N(cases) = 1,242-N(controls) = 860) and the other for diabetic retinopathy (N(cases) = 1,336-N(controls) = 1,231). The effects of each SNP on quantitative traits were analyzed in a French general population-based cohort (N = 4,760) and two French T2D studies (N = 3,480). SNP associations were assessed using logistic or linear regressions.In the French population, we found an association between the G-allele of rs6921438, shown to increase circulating VEGF levels, and increased T2D risk (OR = 1.15; P = 3.7×10(-5)). Furthermore, the same allele was associated with higher glycated hemoglobin levels (β = 0.02%; P = 9.2×10(-3)). However, these findings were not confirmed in the Danes. Conversely, the SNP rs10738760 was not associated with T2D in the French or Danish populations. Despite having adequate statistical power, we did not find any significant effects of rs6921438 or rs10738760 on diabetic microvascular complications or the variation in related traits in T2D patients.In spite of their impact on the variance in circulating VEGF, we did not find any association between SNPs rs6921438 and rs10738760, and the risk of T2D, diabetic nephropathy or retinopathy. The link between VEGF and T2D and its complications might be indirect and more complex than expected.

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.

Targeted therapies in colorectal cancer-an integrative view by PPPM

In developed countries, colorectal cancer (CRC) is the third most common malignancy, but it is the second most frequent cause of cancer-related death. Clinicians are still faced with numerous challenges in the treatment of this disease, and future approaches which target the molecular features of the disorder will be critical for success in this disease setting. Genetic analyses of many solid tumours have shown that up to 100 protein-encoding genes are mutated. Within CRC, numerous genetic alterations have been identified in a number of pathways. Therefore, understanding the molecular pathology of CRC may present information on potential routes for treatment and may also provide valuable prognostic information. This will be particularly pertinent for molecularly targeted treatments, such as anti-vascular endothelial growth factor therapies and anti-epidermal growth factor receptor (EGFR) monoclonal antibody therapy. KRAS and BRAF mutations have been shown to predict response to anti-EGFR therapy. As EGFR can also signal via the phosphatidylinositol 3-kinase (PI3K) kinase pathway, there is considerable interest in the potential roles of members of this pathway (such as PI3K and PTEN) in predicting treatment response. Therefore, a combined approach of new techniques that allow identification of these biomarkers alongside interdisciplinary approaches to the treatment of advanced CRC will aid in the treatment decision-making process and may also serve to guide future therapeutic approaches.

Obesity and intermittent hypoxia increase tumor growth in a mouse model of sleep apnea

BACKGROUND

Intermittent hypoxia and obesity which are two pathological conditions commonly found in patients with obstructive sleep apnea (OSA), potentially enhance cancer progression.

OBJECTIVE

To investigate whether obesity and/or intermittent hypoxia (IH) mimicking OSA affect tumor growth.

METHODS

A subcutaneous melanoma was induced in 40 mice [22 obese (40-45g) and 18 lean (20-25g)] by injecting 10(6) B16F10 cells in the flank. Nineteen mice (10 obese/9 lean) were subjected to IH (6h/day for 17days). A group of 21 mice (12 obese/9 lean) were kept under normoxia. At day 17, tumors were excised, weighed and processed to quantify necrosis and endothelial expression of vascular endothelial growth factor (VEGF) and CD-31. VEGF in plasma was also assessed.

RESULTS

In lean animals, IH enhanced tumor growth from 0.81±0.17 to 1.95±0.32g. In obese animals, a similar increase in tumor growth (1.94±0.18g) was observed under normoxia, while adding IH had no further effect (1.69±0.23g). IH only promoted an increase in tumoral necrosis in lean animals. However, obesity under normoxic conditions increased necrosis, VEGF and CD-31 expression in tumoral tissue. Plasma VEGF strongly correlated with tumor weight (ρ=0.76, p<0.001) in the whole sample; it increased in lean IH-treated animals from 66.40±3.47 to 108.37±9.48pg/mL, p<0.001), while the high baseline value in obese mice (106.90±4.32pg/mL) was unaffected by IH.

CONCLUSIONS

Obesity and IH increased tumor growth, but did not appear to exert any synergistic effects. Circulating VEGF appeared as a crucial mediator of tumor growth in both situations.

VEGF pathway genetic variants as biomarkers of treatment outcome with bevacizumab: an analysis of data from the AViTA and AVOREN randomised trials

BACKGROUND

No biomarkers that could guide patient selection for treatment with the anti-VEGF monoclonal antibody bevacizumab have been identified. We assessed whether genetic variants in the VEGF pathway could act as biomarkers for bevacizumab treatment outcome.

METHODS

We investigated DNA from white patients from two phase 3 randomised studies. In AViTA, patients with metastatic pancreatic adenocarcinoma were randomly assigned to receive gemcitabine and erlotinib plus either bevacizumab or placebo. In AVOREN, patients with metastatic renal-cell carcinoma were randomly assigned to receive interferon alfa-2a plus either bevacizumab or placebo. We assessed the correlation of 138 SNPs in the VEGF pathway with progression-free survival and overall survival in a subpopulation of patients from AViTA. Significant findings were confirmed in a subpopulation of patients from AVOREN and functionally studied at the molecular level.

FINDINGS

We investigated DNA of 154 patients from AViTA, of whom 77 received bevacizumab, and 110 patients from AVOREN, of whom 59 received bevacizumab. Only rs9582036, a SNP in VEGF receptor 1 (VEGFR1 or FLT1), was significantly associated with overall survival in the bevacizumab group of AViTA after correction for multiplicity (per-allele hazard ratio [HR] 2·1, 95% CI 1·45-3·06, p=0·00014). This SNP was also associated with progression-free survival (per-allele HR 1·89, 1·31-2·71, p=0·00081) in bevacizumab-treated patients from AViTA. AC and CC carriers of this SNP exhibited HRs for overall survival of 2·0 (1·19-3·36; p=0·0091) and 4·72 (2·08-10·68; p=0·0002) relative to AA carriers. No effects were seen in placebo-treated patients and a significant genotype by treatment interaction (p=0·041) was recorded, indicating that the VEGFR1 locus containing this SNP serves as a predictive marker for bevacizumab treatment outcome in AViTA. Fine-mapping experiments of this locus identified rs7993418, a synonymous SNP affecting tyrosine 1213 in the VEGFR1 tyrosine-kinase domain, as the functional variant underlying the association. This SNP causes a shift in codon usage, leading to increased VEGFR1 expression and downstream VEGFR1 signalling. This VEGFR1 locus correlated significantly with progression-free survival (HR 1·81, 1·08-3·05; p=0·033) but not overall survival (HR 0·91, 0·45-1·82, p=0·78) in the bevacizumab group in AVOREN.

INTERPRETATION

A locus in VEGFR1 correlates with increased VEGFR1 expression and poor outcome of bevacizumab treatment. Prospective assessment is underway to validate the predictive value of this novel biomarker.

FUNDING

F Hoffmann-La Roche.

Relation of vascular growth factors with CT-derived measures of body fat distribution: the Framingham Heart Study

BACKGROUND

Visceral adiposity is associated with metabolic risk. Given that angiogenesis is a key feature of adipogenesis, variation in the association of levels of circulating vascular growth factors (and their soluble receptors) with distinct body fat compartments may explain differences in the systemic pathogenicity of regional fat depots.

METHODS AND RESULTS

Four body fat compartments [visceral adipose tissue (VAT), sc adipose tissue (SAT), thoracic periaortic fat, and pericardial fat] derived from computed tomography were related to serum concentrations of vascular endothelial growth factor (VEGF), the soluble VEGF receptor (fms-like tyrosine kinase-1), hepatocyte growth factor (HGF), and angiopoietin-2 and its soluble receptor (soluble tyrosine kinase with immunoglobulin-like and EGF-like domains 2 sTie-2) in 1806 Framingham Heart Study participants (mean age 44.9 yr, 44.5% women). In multivariable models, we observed positive associations between several fat compartments and VEGF and HGF levels. The magnitude of the associations were similar for VAT, SAT, and periaortic fat. We observed effect modification by sex. A stronger association was observed between VAT and HGF levels in women; higher VAT and periaortic fat were jointly associated with higher HGF concentrations (P=0.02 and P=0.051, respectively). In women within the highest tertile of VAT, HGF levels significantly increased with higher periaortic fat (P=0.0005).

CONCLUSIONS

In our large community-based sample, greater adiposity was associated with higher circulating growth factor levels in general. Additional studies are warranted to confirm the stronger association of VAT and periaortic fat with HGF in women and to examine its potential contribution to the sex-related differences in cardiometabolic risk.

Circulating vascular growth factors and central hemodynamic load in the community

Mean and pulsatile components of hemodynamic load are related to cardiovascular disease. Vascular growth factors play a fundamental role in vascular remodeling. The links between growth factors and hemodynamic load components are not well described. In 3496 participants from the Framingham Heart Study third generation cohort (mean age: 40±9 years; 52% women), we related 4 tonometry-derived measures of central arterial load (carotid femoral pulse wave velocity and forward pressure wave, mean arterial pressure, and the global reflection coefficient) to circulating concentrations of angiopoietin 2, its soluble receptor; vascular endothelial growth factor, its soluble receptor; hepatocyte growth factor; insulin-like growth factor 1; and its binding protein 3. Using multivariable linear regression models, adjusted for standard cardiovascular risk factors, serum insulin-like growth factor 1 concentrations were negatively associated with carotid femoral pulse wave velocity, mean arterial pressure, and reflection coefficient (P≤0.01 for all), whereas serum vascular endothelial growth factor levels were positively associated with carotid femoral pulse wave velocity and mean arterial pressure (P<0.04). Serum insulin-like growth factor binding protein 3 and soluble angiopoietin 2 receptor levels were positively related to mean arterial pressure and to forward pressure wave, respectively (P<0.05). In our cross-sectional study of a large community-based sample, circulating vascular growth factor levels were related to measures of mean and pulsatile hemodynamic load in a pattern consistent with the known physiological effects of insulin-like growth factor 1 and vascular endothelial growth factor.

Identification of cis- and trans-acting genetic variants explaining up to half the variation in circulating vascular endothelial growth factor levels

RATIONALE

Vascular endothelial growth factor (VEGF) affects angiogenesis, atherosclerosis, and cancer. Although the heritability of circulating VEGF levels is high, little is known about its genetic underpinnings.

OBJECTIVE

Our aim was to identify genetic variants associated with circulating VEGF levels, using an unbiased genome-wide approach, and to explore their functional significance with gene expression and pathway analysis.

METHODS AND RESULTS

We undertook a genome-wide association study of serum VEGF levels in 3527 participants of the Framingham Heart Study, with preplanned replication in 1727 participants from 2 independent samples, the STANISLAS Family Study and the Prospective Investigation of the Vasculature in Uppsala Seniors study. One hundred forty single nucleotide polymorphism (SNPs) reached genome-wide significance (P<5×10(-8)). We found evidence of replication for the most significant associations in both replication datasets. In a conditional genome-wide association study, 4 SNPs mapping to 3 chromosomal regions were independently associated with circulating VEGF levels: rs6921438 and rs4416670 (6p21.1, P=6.11×10(-506) and P=1.47×10(-12)), rs6993770 (8q23.1, P=2.50×10(-16)), and rs10738760 (9p24.2, P=1.96×10(-34)). A genetic score including these 4 SNPs explained 48% of the heritability of serum VEGF levels. Six of the SNPs that reached genome-wide significance in the genome-wide association study were significantly associated with VEGF messenger RNA levels in peripheral blood mononuclear cells. Ingenuity pathway analyses showed found plausible biological links between VEGF and 2 novel genes in these loci (ZFPM2 and VLDLR).

CONCLUSIONS

Genetic variants explaining up to half the heritability of serum VEGF levels were identified. These new insights provide important clues to the pathways regulating circulating VEGF levels.

Vitamin C status is related to proinflammatory responses and impaired vascular endothelial function in healthy, college-aged lean and obese men

Vitamin C supplementation has been suggested to reduce cardiovascular disease risk. However, no studies have examined the relationship between vitamin C status and vascular dysfunction in lean and obese individuals in the absence of supplementation. We examined whether vascular function is interrelated with vitamin C status and inflammation in healthy, college-aged lean and obese men with no history of dietary supplementation. A cross-sectional study was conducted during winter 2008 in lean and obese men aged 21±3 years (n=8/group). Brachial artery flow-mediated dilation (FMD) was measured to determine vascular endothelial function. Plasma antioxidants (vitamin C, vitamin E, and thiols), inflammatory proteins (C-reactive protein [CRP], myeloperoxidase [MPO], and cytokines), and cellular adhesion molecules were measured. Participants also completed 3-day food records on the days preceding their vascular testing. Group differences were evaluated by t tests, and correlation coefficients were determined by linear regression. FMD was 21% lower (P<0.05) in obese men. They also had 51% lower vitamin C intakes and 38% lower plasma vitamin C concentrations. Obese men had greater plasma concentrations of CRP, MPO, inflammatory cytokines, and cellular adhesion molecules. Participants' CRP and MPO were each inversely related (P<0.05) to FMD (r=-0.528 and -0.625) and plasma vitamin C (r=-0.646 and -0.701). These data suggest that low vitamin C status is associated with proinflammatory responses and impaired vascular function in lean and obese men. Additional study is warranted to determine whether improving dietary vitamin C intakes from food attenuate vascular dysfunction.

Coronary angiogenesis during experimental hypertension: is it reversible?

BACKGROUND

We investigated coronary angiogenesis and serum vascular endothelial growth factor (VEGF) and its soluble receptor-1 (sFlt-1) concentrations in two-kidney one-clip (2K1C) hypertensive rats before and after reversal of hypertension.

METHODS

THE ANIMAL GROUPS WERE: (i) sham-clipped for 12 weeks; (ii) 2K1C for 12 weeks; (iii) sham-clipped for 12 weeks and unclipped for 12 weeks; and (iv) 2K1C for 12 weeks and unclipped for 12 weeks. Blood samples were taken before experiments and after clipping and unclipping; capillary density was also evaluated.

RESULTS

Our results showed that blood pressure in hypertensive animals was higher than sham group (175 ± 10 vs. 110.3 ± 11.3 mmHg; p < 0.05). Unclipping significantly reduced blood pressure in hypertensive rats (p < 0.05). Serum VEGF and sFlt-1 levels in hypertensive group were significantly lower than sham group (VEGF: 74.36 ± 5.85 vs. 104.07 ± 7.75 pg/ml; sFlt-1: 426.67 ± 25.74 vs. 690.76 ± 41.14 pg/ml, respectively; p < 0.05). Unclipping in hypertensive animals increased serum VEGF and sFlt-1 concentrations (VEGF: 93.65 ± 8.61 vs. 74.36 ± 5.85 pg/ml; sFlt-1: 742.05 ± 79.23 vs. 426.67 ± 25.74 pg/ml, respectively; p < 0.05). In hypertensive animals, capillary density in the heart was higher than sham group, non-significantly (p > 0.05) and after unclipping, it reached to sham group level.

CONCLUSIONS

It seems that changes in capillary density and serum VEGF and sFlt-1 concentrations in renovascular hypertension are reversible by removing the cause of hypertension and it shows the importance of early diagnosis and treatment of hypertension in clinical condition.

Vascular Endothelial Growth Factor, Soluble Fms-Like Tyrosine Kinase 1, and the Severity of Coronary Artery Disease

Background: The association between vascular endothelial growth factor (VEGF), soluble fms-like tyrosine kinase 1 (sFlt-1), and coronary artery disease (CAD) was investigated. Methods: We enrolled 112 hypertensive patients with proven CAD and 112 hypertensive controls matched for age and gender. The severity of CAD was assessed by the most severe clinical presentation of CAD in patients’ history and by the number of diseased vessels. Results: Vascular endothelial growth factor level was lower, whereas sFlt-1 level was higher in the CAD group compared to the controls. Diabetes mellitus (P = .001), smoking (P = .004), and higher sFlt-1 level (P = .01) were independently associated with CAD. Younger age (P = .02), smoking (P = .049), and higher VEGF levels (P = .02) were independently associated with a history of myocardial infarction (MI), whereas higher sFlt-1 level (P = .01) was independently associated with multivessel disease. Conclusion: Plasma sFlt-1 levels are positively associated with the presence of CAD and are associated with angiographical severity of CAD.

Hepatocyte growth factor and the risk of ischemic stroke developing among postmenopausal women: results from the Women's Health Initiative

BACKGROUND AND PURPOSE

Hepatocyte growth factor (HGF) is a potent angiogenic factor and may play a role in the development and progression of atherosclerotic lesions, the underlying mechanism of cardiovascular disease. However, there have been no prospective studies examining the relationship between HGF levels and risk of stroke.

METHODS

We conducted a nested case-control study (972 incident stroke cases and 1:1 age-matched and race-matched controls) to prospectively evaluate the association between plasma HGF and risk of ischemic stroke within the Women's Health Initiative Observational Study, a cohort of postmenopausal women aged 50 to 79 years.

RESULTS

Baseline HGF levels were correlated positively with body mass index, systolic blood pressure, low-density lipoprotein cholesterol, insulin resistance, and inflammatory markers, such as C-reactive protein, and inversely with high-density lipoprotein cholesterol (all P<0.05). Baseline HGF levels were higher among cases than controls (geometric means, 601.8 vs 523.2 pg/mL; P=0.003). Furthermore, the risk of incident ischemic stroke was significantly greater among women in the highest vs lowest quartile of plasma HGF levels (OR, 1.46; 95% CI, 1.12-1.91; P(trend)=0.003) in a conditional logistic regression model that adjusted for body mass index. These results were only slightly attenuated after further adjustment for additional stroke risk factors (OR, 1.39; 95% CI, 1.04-1.85; P(trend)=0.023).

CONCLUSIONS

Circulating levels of HGF are associated with an increased risk of incident ischemic stroke, independent of obesity and other risk factors for cardiovascular disease, among postmenopausal women aged 50 to 79 years.

Clinical and genetic correlates of circulating angiopoietin-2 and soluble Tie-2 in the community

BACKGROUND

Experimental studies suggest that endothelial growth factors play an important role in angiogenesis and vascular remodeling. The clinical and genetic correlates of circulating angiopoietin-2 (Ang-2) and its soluble receptor/regulator Tie-2 (sTie-2) have not been determined in a community-based sample.

METHODS AND RESULTS

Serum Ang-2 and sTie-2 were assayed in 3778 third-generation cohort participants of the Framingham Heart Study (mean age, 40+/-9 years; 53% women). Clinical correlates and heritability of both biomarkers were assessed using generalized estimating equations and variance-component analyses. Ang-2 levels were higher and sTie-2 levels were lower in women than in men. Ang-2 was positively related to age, smoking, systolic blood pressure, hypertension treatment, and diabetes (P<0.05 for all) but was inversely associated with total cholesterol and diastolic blood pressure (P<0.0001 for both), and sTie-2 was positively associated with body mass index, diabetes, and triglycerides but was inversely related to age, alcohol consumption, and glomerular filtration rate (P<0.05 for all). Both Ang-2 and sTie-2 were higher in participants with metabolic syndrome (P<0.005), with stronger associations of Ang-2 with blood pressure traits and of sTie-2 with obesity-dyslipidemia components. Heritability estimates for Ang-2 and sTie-2 were 27% and 56%, respectively (P<0.0001). A region on chromosome 9 was significantly linked to circulating sTie-2 levels (logarithm of the odds score, 8.31).

CONCLUSION

Circulating levels of Ang-2 and sTie-2 are heritable traits associated with cardiovascular disease risk factors, including the metabolic syndrome. These observations are consistent with the notion that angiogenesis and vascular remodeling are determined in part by genetic influences and associated with metabolic risk factors.

Omentum-derived stromal cells improve myocardial regeneration in pig post-infarcted heart through a potent paracrine mechanism

Cell-based therapy could be a valid option to treat myocardial infarct (MI). Adipose-derived stromal cells (ADStCs) have demonstrated tissue regenerative potential including cardiomyogenesis. Omentum is an extremely rich source of visceral fat and its accumulation seems to correlate with cardiovascular diseases. We investigated the capacity of human fat Omentum-derived StCs (FOStCs) to affect heart function upon acute infarct in pigs induced by permanent ligation of the anterior interventricular artery (IVA). We demonstrated for the first time that the local injection of 50x10(6) of FOStCs ameliorates the functional parameters of post-infarct heart. Most importantly, histology of FOStCs treated hearts demonstrated a substantial improvement of cardiomyogenesis. In culture, FOStCs produced an impressive number and amount of angiogenic factors and cytokines. Moreover, the conditioned medium of FOStCs (FOStCs-CM) stimulates in vitro cardiac endothelial cells (ECs) proliferation and vascular morphogenesis and inhibits monocytes, EC activation and cardiomyocyte apoptosis. Since FOStCs in vivo did not trans-differentiate into cardiomyocyte-like cells, we conclude that FOStCs efficacy was presumably mediated by a potent paracrine mechanism involving molecules that concomitantly improved angiogenesis, reduced inflammation and prevented cardiomyocytes death. Our results highlight for the first time the important role that human FOStCs may have in cardiac regeneration.