Vascular endothelial growth factor haplotypes associated with childhood obesity

Transcriptome analysis of perirenal fat from Spanish Assaf suckling lamb carcasses showing different levels of kidney knob and channel fat

Introduction

Suckling lamb meat is highly appreciated in European Mediterranean countries because of its mild flavor and soft texture. In suckling lamb carcasses, perirenal and pelvic fat depots account for a large fraction of carcass fat accumulation, and their proportions are used as an indicator of carcass quality.

Material and Methods

This study aimed to characterize the genetic mechanisms that regulate fat deposition in suckling lambs by evaluating the transcriptomic differences between Spanish Assaf lambs with significantly different proportions of kidney knob and channel fat (KKCF) depots in their carcasses (4 High-KKCF lambs vs. 4 Low-KKCF lambs).

Results

The analyzed fat tissue showed overall dominant expression of white adipose tissue gene markers, although due to the young age of the animals (17-36 days), the expression of some brown adipose tissue gene markers (e.g., UCP1, CIDEA) was still identified. The transcriptomic comparison between the High-KKCF and Low-KKCF groups revealed a total of 80 differentially expressed genes (DEGs). The enrichment analysis of the 49 DEGs with increased expression levels in the Low-KKCF lambs identified significant terms linked to the biosynthesis of lipids and thermogenesis, which may be related to the higher expression of the UCP1 gene in this group. In contrast, the enrichment analysis of the 31 DEGs with increased expression in the High-KKCF lambs highlighted angiogenesis as a key biological process supported by the higher expression of some genes, such as VEGF-A and THBS1, which encode a major angiogenic factor and a large adhesive extracellular matrix glycoprotein, respectively.

Discussion

The increased expression of sestrins, which are negative regulators of the mTOR complex, suggests that the preadipocyte differentiation stage is being inhibited in the High-KKCF group in favor of adipose tissue expansion, in which vasculogenesis is an essential process. All of these results suggest that the fat depots of the High-KKCF animals are in a later stage of development than those of the Low-KKCF lambs. Further genomic studies based on larger sample sizes and complementary analyses, such as the identification of polymorphisms in the DEGs, should be designed to confirm these results and achieve a deeper understanding of the genetic mechanisms underlying fat deposition in suckling lambs.

VEGF and VEGFB Play Balancing Roles in Adipose Differentiation, Gene Expression, and Function

Obesity is the result of abnormal adipose development and energy metabolism. Using vascular endothelial growth factor (VEGF) B-knockout and inducible VEGF downregulation mouse models, we have shown that VEGFB inactivation caused expansion of white adipose, whitening of brown adipose, an increase in fat accumulation, and a reduction in energy consumption. At the same time, expression of the white adipose-associated genes was increased and brown adipose-associated genes decreased. VEGF repression, in contrast, induced brown adipose expansion and brown adipocyte development in white adipose, increased energy expenditure, upregulated brown adipose-associated genes, and downregulated white adipose-associated genes. When VEGFB-knockout and VEGF-repressed mice are crossed together, VEGF and VEGFB can counteractively regulate large numbers of genes and efficiently reverse each other's roles. These genes, under counteractive VEGF and VEGFB regulations, include transcription factors, adhesion molecules, and metabolic enzymes. This balancing role is confirmed by morphologic and functional changes. This study reports that VEGF and VEGFB counteractively regulate adipose development and function in energy metabolism.

Genetic Contributions to Childhood Obesity: Association of Candidate Gene Polymorphisms and Overweight/Obesity in Korean Preschool Children

This study was aimed to investigate the association of candidate gene polymorphisms and obesity or overweight in young Korean children. A total of 190 Korean preschool children (96 control, 48 overweight, and 46 obese children) were genotyped for the angiotensin converting enzyme (ACE) insertion (I)/deletion (D), angiotensin II type 2 receptor (AT2) C3123A, transforming growth factor (TGF)-β1 T869C, vascular endothelial growth factor (VEGF) T460C, and tumor necrosis factor (TNF)-α G308A polymorphisms. No differences were found among the groups with respect to age, sex, birth weight, blood pressure levels, and serum concentrations of glucose and total cholesterol. Obese children showed a higher incidence of ACE DD genotype and D allelic frequency compared to the controls (odds ratio [OR], 2.7, 95% confidence interval [CI], 1.01-7.21; OR, 2.5, 95% CI, 1.49-4.19; all P < 0.05). The frequency of TC genotype and C allele in the TGF-β1 T869C polymorphism (OR, 2.08, 95% CI, 1.01-4.27; OR, 1.93, 95% CI, 1.15-3.21) and that in the VEGF T460C polymorphism (OR, 2.5, 95% CI, 1.19-5.28; OR, 2.15, 95% CI, 1.26-3.68) was also higher in obese children than in control subjects (all P < 0.05). Overweight children exhibited a higher frequency of the A allele in the AT2 C3123A polymorphism compared to the controls (OR, 1.72, 95% CI, 1.03-2.88, P < 0.05). There were no differences in the TNF-α G308A polymorphism among the groups. The ACE I/D, AT2 C3123A, TGF-β1 T869C, and VEGF T460C polymorphisms can affect susceptibility to obesity or overweight in Korean children.

Pharmacogenetics of erectile dysfunction: navigating into uncharted waters

Sildenafil and other PDE-5 inhibitors have revolutionized erectile dysfunction (ED) treatment. However, a significant number of patients do not respond or present adverse reactions to these drugs. While genetic polymorphisms may underlie this phenomenon, very little research has been undertaken in this research field. Most of the current knowledge is based on sildenafil, thus almost completely ignoring other important pharmacological therapies. Currently, the most promising genes with pharmacogenetic implications in ED are related to the nitric oxide and cGMP pathway, although other genes are likely to affect the responsiveness to treatment of ED. Nevertheless, the small number of studies available opens the possibility of further exploring other genes and phenotypes related to ED. This article provides a comprehensive overview of the genes being tested for their pharmacogenetic relevance in the therapy of ED.

Polymorphisms in VEGFA gene affect the antihypertensive responses to enalapril

PURPOSE

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor that affects blood pressure by promoting vasodilation mediated by nitric oxide. Angiotensin-converting enzyme inhibitors (ACEi) up-regulate the VEGF expression; thus, genetic polymorphisms in the VEGFA gene could affect the antihypertensive responses to these drugs.

METHODS

Hypertensive patients (n = 102) were prospectively treated only with the ACEi enalapril for 60 days. We compared the effect of VEGFA polymorphisms on changes in blood pressure after enalapril treatment. In addition, multiple linear regression analysis was carried out to assess the effect of covariates on blood pressure. Genotypes for g.-2578C>A (rs699947), g.-1154G>A (rs1570360), and g.-634G>C (rs2010963) VEGFA polymorphisms were determined, and haplotype frequencies were estimated.

RESULTS

Individuals carrying the CA and AA genotypes for the g.-2578C>A polymorphism and the AGG haplotype showed more intense decrease in blood pressure in response to enalapril 20 mg/day. A multiple linear regression analysis showed that the AA genotype for the g.-2578C>A polymorphism and the AGG haplotype are associated with more intense decrease in blood pressure in response to enalapril 20 mg/day, while the CC genotype for the g.-2578C>A polymorphism and the CGG haplotype are associated with the opposite effect.

CONCLUSIONS

These findings suggest that polymorphisms in VEGFA gene may affect the antihypertensive responses to enalapril.

The effects of NAMPT haplotypes and metabolic risk factors on circulating visfatin/NAMPT levels in childhood obesity

OBJECTIVE

Polymorphisms in the NAMPT gene, which encodes the adipocytokine visfatin/nicotinamide phosphorybosil transferase (NAMPT), affect the circulating visfatin/NAMPT levels and are associated with obesity and cardiovascular diseases. However, no study has tested the hypothesis that NAMPT haplotypes could affect visfatin/NAMPT levels in case of childhood obesity. We investigated the effects of traditional metabolic risk factors (MRFs) and NAMPT polymorphisms T/C (rs1319501) and A/G (rs3801266) or haplotypes on visfatin/NAMPT levels in obese children and adolescents, and whether NAMPT polymorphisms and/or haplotypes are associated with susceptibility to childhood obesity.

METHODS

We studied 175 control, 99 obese and 82 obese with ⩾ 3 MRFs children and adolescents. Genotypes were determined by a Taqman allele discrimination assay and real-time PCR. The plasma visfatin/NAMPT level was measured using an enzyme immunoassay.

RESULTS

Obese children and adolescents with ⩾ 3 MRFs had higher plasma visfatin/NAMPT levels in comparison with control children and adolescents (P<0.05). Although positive associations were observed between visfatin/NAMPT and body mass index (rs = 0.157; P = 0.034) as well as visfatin/NAMPT and waist circumference (rs = 0.192; P = 0.011), visfatin/NAMPT and high-density lipoprotein cholesterol were inversely associated (rs = -0.162; P = 0.031). No significant differences in genotype, allele or haplotype frequency distributions for the studied polymorphisms were found when the three groups were compared. However, higher plasma visfatin/NAMPT levels were found in control and obese subjects carrying the GG genotype for the A/G (rs3801266) polymorphism (P<0.05) but not in obese children with ⩾ 3 MRFs. Moreover, control subjects carrying the 'T-G' haplotype showed higher plasma visfatin/NAMPT levels. NAMPT genotypes or haplotypes were not associated with childhood obesity.

CONCLUSIONS

Obesity in children with ⩾ 3 MRFs increases plasma visfatin/NAMPT levels, and this marker was associated with body mass index and waist circumference. The A/G polymorphism and NAMPT haplotypes affect plasma visfatin/NAMPT levels in controls but not in obese children with ⩾ 3 MRFs. These results suggest that obesity and MRFs are more influential than genetic polymorphisms in the determination of visfatin/NAMPT levels in obese children. Further research is necessary to explain why the GG genotype is not associated with increased visfatin/NAMPT levels in obese children with ⩾ 3 MRFs.

The beneficial role of vitamin D in obesity: possible genetic and cell signaling mechanisms

The prevalence rates of overweight and obesity are considered an important public issue in the United States, and both of these conditions are increasing among both children and adults. There is evidence of aberrations in the vitamin D-endocrine system in obese subjects. Vitamin D deficiency is highly prevalent in patients with obesity, and many studies have demonstrated the significant effect of calcitriol on adipocytes. Genetic studies have provided an opportunity to determine which proteins link vitamin D to obesity pathology, including the vitamin D receptor, toll-like receptors, the renin-angiotensin system, apolipoprotein E, vascular endothelial growth factor, and poly (ADP-ribose) polymerase-1. Vitamin D also exerts its effect on obesity through cell-signaling mechanisms, including matrix metalloproteinases, mitogen-activated protein kinase pathways, the reduced form of nicotinamide adenine dinucleotide phosphate, prostaglandins, reactive oxygen species, and nitric oxide synthase.

In conclusion, vitamin D may have a role in obesity. The best form of vitamin D for use in the obese individuals is calcitriol because it is the active form of the vitamin D₃ metabolite, its receptors are present in adipocytes, and modulates inflammatory cytokine expression.

Association between vascular endothelial growth factor +936 C/T gene polymorphism and age-related macular degeneration

Objectives

The pathogenesis of age-related macular degeneration (AMD) remains unknown. Vascular endothelial growth factor (VEGF) is an important regulator of angiogenesis and a target for inhibition therapy in wet AMD. This study investigated the association between the VEGF +936 C/T gene polymorphism and AMD, in a Chinese Han population.

Methods

Patients with AMD, and age- and sex-matched controls were enrolled. Restriction fragment length polymorphism was used to analyse the VEGF +936 polymorphism in the promoter and the 3′ untranslated region of the gene.

Results

The study included 200 AMD patients and 200 control subjects. There was a significantly higher prevalence of the TT genotype among AMD patients (9.0%) compared with controls (3.5%); the odds ratio for this genotype in AMD patients was 2.73 (95% confidence intervals 1.11, 6.68). There were no significant associations between any genotype and AMD subphenotypic categories (early, geographic atrophy, choroidal neovascularization).

Conclusions

The present study findings suggested that the VEGF +936 TT genotype was associated with AMD among Han Chinese patients.

Cancer prevention by targeting angiogenesis

Healthy individuals can harbour microscopic tumours and dysplastic foci in different organs in an undetectable and asymptomatic state for many years. These lesions do not progress in the absence of angiogenesis or inflammation. Targeting both processes before clinical manifestation can prevent tumour growth and progression. Angioprevention is a chemoprevention approach that interrupts the formation of new blood vessels when tumour cell foci are in an indolent state. Many efficacious chemopreventive drugs function by preventing angiogenesis in the tumour microenvironment. Blocking the vascularization of incipient tumours should maintain a dormancy state such that neoplasia or cancer exist without disease. The current limitations of antiangiogenic cancer therapy may well be related to the use of antiangiogenic agents too late in the disease course. In this Review, we suggest mechanisms and strategies for using antiangiogenesis agents in a safe, preventive clinical angioprevention setting, proposing different levels of clinical angioprevention according to risk, and indicate potential drugs to be employed at these levels. Finally, angioprevention may go well beyond cancer in the prevention of a range of chronic disorders where angiogenesis is crucial, including different forms of inflammatory or autoimmune diseases, ocular disorders, and neurodegeneration.