Expression of ghrelin gene in peripheral blood mononuclear cells and plasma ghrelin concentrations in patients with metabolic syndrome

Effect of the GHRL gene (rs696217) polymorphism on the metabolic disorders in patients with obesity in the Ukrainian population

Objective. Over the past four decades, the prevalence of obesity has tripled and limited genetic studies with specific SNPs have been conducted, but no investigations using ghrelin and obestatin prepropeptide (GHRL) gene have been reported in the Ukrainians population. The aim of this study was to evaluate changes in the level of metabolic hormones in the blood of obese patients in relation to the GHRL (rs696217) polymorphism. Methods. The study involved 53 obesity cases and 48 non-obesity subjects (controls). The GHRL (rs696217) polymorphism was genotyped using a TaqMan real-time polymerase chain reaction method. Blood hormones were determined with commercially available kits using a Multi-skan FC analyzer. Results. Carriers of the T allele of the GHRL (rs696217) polymorphism were statistically significantly more in patients diagnosed with obesity compared to controls indicating a genetically determined cause of obesity. We also established a significant effect of the presence of the T allele of the GHRL (rs696217) polymorphism on the decrease in the adiponectin level and the increase of resistin level in obese patients. The study of the effect of genotypes (TT, GT, GG) of the GHRL (rs696217) polymorphism on the metabolic hormone levels in the blood of obese patients did not show reliably significant differences. Conclusions. The presence of the T allele of the GHRL (rs696217) polymorphism in Ukrainian population indicates an increased risk of the obesity development regardless on the homozygous or heterozygous genotype.

Effectiveness of Resistance Training and Associated Program Characteristics in Patients at Risk for Type 2 Diabetes: a Systematic Review and Meta-analysis

BACKGROUND

Resistance training (RT) is an effective intervention for glycemic control and cardiometabolic health in individuals with type 2 diabetes (T2D). However, the use of RT in individuals at risk for T2D to prevent or delay the onset of T2D, and RT program characteristics that are most effective are still unknown. The purpose of this review is to determine the effects of RT on cardiometabolic risk factors in those at risk for T2D and to examine RT program characteristics associated with intervention effectiveness.

METHODS

PubMed, Cochrane, Web of Science, and Embase databases were systematically searched for published controlled trials that compared cardiometabolic outcomes in adults with cardiometabolic risk for those that underwent an RT intervention with those that did not. A systematic review and meta-analysis was conducted to determine the effect of RT on glycosylated hemoglobin (HbA1c), fasting plasma glucose (FPG), body fat percentage (BF%), total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and triglycerides (TG). Additional analyses examined effects of intervention duration and dietary intervention on FPG and TG.

RESULTS

Fourteen trials with 668 participants were included. For RT compared to controls, the standardized mean difference (SMD) was -1.064 for HbA1c (95% confidence interval [CI] -1.802 to -0.327; p=0.005), -0.99 for FPG (95% CI -1.798 to -0.183; p=0.016), -0.933 for TC (95% CI -1.66 to -0.206; p=0.012), -0.840 for BF% (95% CI -1.429 to -0.251; p=0.005), -0.693 for HDL (95% CI -1.230 to -0.156; p=0.011), -1.03 for LDL (95% CI -2.03 to -0.050; p=0.039), and -0.705 for TG (95% CI -1.132 to -0.279; p=0.001).

CONCLUSIONS

RT is beneficial for improving glycemic control, BF%, and blood lipids in those at risk for diabetes. The addition of a dietary component did not result in larger reductions in FPG and TG than RT alone.

PROSPERO REGISTRATION ID

CRD42019122217.

Association of proinflammatory genes expression with serum interleukin 1β and free fatty acids in metabolically healthy and unhealthy abdominally obese individuals: a case-control study

Background

Proinflammatory genes are highly expressed in several metabolic disorders associated with obesity. But it is not clarified whether gene expression levels and downstream inflammatory markers are related to the metabolic state or the presence of obesity. Hence, the present study aimed to compare Toll-Like Receptor 2 (TLR2), Myeloid Differentiation Factor 88 (MyD88), and NFĸB mRNA expression levels between metabolically healthy abdominally obese (MHAO) and metabolically unhealthy abdominally obese (MUAO) individuals.

Results

We compared mRNA expression levels of the genes as well as serum FFAs and IL-1β in MUAO (n = 36) and MHAO (n = 34) groups. Serum FBS, TG, and HDL-C in addition to systolic and diastolic blood pressure were significantly higher in MUAO than MHAO groups (p < 0.05). The odds of MUAO was significantly decreased with high HDL-C (OR = 0.22, 95%CI: 0.08–0.63) and increased with high FBS (OR = 7.04, 95%CI: 1.42–34.69) and TG (OR = 30.55, 95%CI: 7.48–60.67). There were no significant differences in proinflammatory genes as well as serum FFAs and IL-1β between the two groups. No associations were found between the genes expression and serum markers. However, NFĸB expression was significantly correlated with TLR2 and MyD88 (r = 0.747; p < 0.001). Significant correlations were also noticed between TLR2 and MyD88 expression as well as between serum FFAs and IL-1β in each group (p < 0.001).

Conclusion

Serum concentration of IL-1β, FFAs, and mRNA expression levels of TLR2, MyD88, and NFĸB may be resulted from abdominal obesity and not be related to the presence or absence of metabolic health.

Aerobic, resistance or combined training: A systematic review and meta-analysis of exercise to reduce cardiovascular risk in adults with metabolic syndrome

BACKGROUND AND AIMS

Exercise is beneficial to individuals with metabolic syndrome (MetS). An understudied group, who represent the majority of the MetS population, are individuals who have not developed diabetes. This review examined aerobic, resistance and combined (aerobic + resistance) exercise for cardiovascular risk factors in MetS without diabetes.

METHODS

Eight electronic databases were searched up to September 2017 for randomised controlled trials >4 weeks in duration that compared an exercise intervention to the non-exercise control in MetS without diabetes. MetS criteria, cardiorespiratory fitness and cardiovascular risk factors were meta-analysed in a random effects model.

RESULTS

Eleven studies with 16 interventions were included (12 aerobic, 4 resistance). Aerobic exercise significantly improved waist circumference -3.4 cm (p < 0.01), fasting glucose -0.15 mmol/L (p = 0.03), high-density cholesterol 0.05 mmol/L (p = 0.02), triglycerides -0.29 mmol/L (p < 0.01), diastolic blood pressure -1.6 mmHg (p = 0.01), and cardiorespiratory fitness 4.2 ml/kg/min (p < 0.01), among other outcomes. No significant effects were determined following resistance exercise possibly due to limited data. Sub-analyses suggested that aerobic exercise progressed to vigorous intensity, and conducted 3 days/week for ≥12 weeks offered larger and more widespread improvements.

CONCLUSIONS

Aerobic exercise following current guidelines offers widespread benefits to individuals with MetS without diabetes. More studies on resistance/combined exercise programs in MetS are required to improve the quality of evidence.

The effect of exercise training on clinical outcomes in patients with the metabolic syndrome: a systematic review and meta-analysis

Background

Purpose: to establish if exercise training improves clinical outcomes in people with metabolic syndrome (MetS). Registered with PROSPERO international prospective register of systematic reviews (https://www.crd.york.ac.uk/PROSPERO/Identifier:CRD42017055491). Data sources: studies were identified through a MEDLINE search strategy (1985 to Jan 12, 2017), Cochrane controlled trials registry, CINAHL and SPORTDiscus. Study selection: prospective randomized or controlled trials of exercise training in humans with metabolic syndrome, lasting 12 weeks or more.

Results

We included 16 studies with 23 intervention groups; 77,000 patient-hours of exercise training. In analyses of aerobic exercise studies versus control: body mass index was significantly reduced, mean difference (MD) −0.29 (kg m⁻²) (95% CI −0.44, −0.15, p < 0.0001); body mass was significantly reduced, MD −1.16 kg (95% CI −1.83, −0.48, p = 0.0008); waist circumference was significantly reduced MD −1.37 cm (95% CI −2.02, −0.71, p < 0.0001), peak VO₂ was significantly improved MD 3.00 mL kg⁻¹ min⁻¹ (95% CI 1.92, 4.08, p < 0.000001); systolic blood pressure and diastolic blood pressure were significantly reduced, MD −2.54 mmHg (95% CI −4.34, −0.75, p = 0.006), and, MD −2.27 mmHg (95% CI −3.47, −1.06, p = 0.0002) respectively; fasting blood glucose was significantly reduced MD −0.16 mmol L⁻¹ (95% CI −0.32, −0.01, p = 0.04); triglycerides were significantly reduced MD −0.21 mmol L⁻¹ (95% CI −0.29, −0.13, p < 0.00001); and low density lipoprotein was significantly reduced MD −0.03 mmol L⁻¹ (95% CI −0.05, −0.00, p = 0.02). In analyses of combined exercise versus control: waist circumference, MD −3.80 cm (95% CI −5.65, −1.95, p < 0.0001); peak VO₂ MD 4.64 mL kg⁻¹ min⁻¹ (95% CI 2.42, 6.87, p < 0.0001); systolic blood pressure MD −3.79 mmHg (95% CI −6.18, −1.40, p = 0.002); and high density lipoprotein (HDL) MD 0.14 (95% CI 0.04, 0.25, p = 0.009) were all significantly improved. We found no significant differences between outcome measures between the two exercise interventions.

Conclusions

Exercise training improves body composition, cardiovascular, and, metabolic outcomes in people with metabolic syndrome. For some outcome measures, isolated aerobic exercise appears optimal.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-017-0590-y) contains supplementary material, which is available to authorized users.

Gene expression modulation of lipid and central energetic metabolism related genes by high-fat diet intake in the main homeostatic tissues

HF diet feeding affects the energy balance by transcriptional metabolic adaptations, based in direct gene expression modulation, perinatal programing and transcriptional factor regulation, which could be affected by the animal model, gender or period of dietary treatment.

Dietary fat alters the expression of cortistatin and ghrelin systems in the PBMCs of elderly subjects: putative implications in the postprandial inflammatory response

SCOPE

Dietary fat influences systemic inflammatory status, which determines the progression of age-associated diseases. Since somatostatin (SST), cortistatin (CORT), and ghrelin systems modulate inflammatory response, we aim to comprehensively characterize the presence and regulation of the components of these systems in the peripheral blood mononuclear cells (PMBCs), a subset of white blood cells placed at the crossroad between diet and inflammation, in response to diets with different fat composition, and during the postprandial phase in elderly subjects.

METHODS AND RESULTS

The applied nutrigenomic, inflammation-related PBMC-based approach revealed that the majority of components of SST/CORT and ghrelin systems are present in the human PBMCs. Particularly, CORT, SST/CORT receptors (sst2, sst3, sst5, and sst5TMD4), ghrelin, its acylating enzyme (GOAT), In1-ghrelin variant, and GHSR1b were detected in PBMCs. Their expression was altered in the long-term by diet composition, and in the short-term, during the postprandial phase. Of particular relevance is the postprandial elevation of CORT, sst2, and sst5 expression in PBMCs of subjects under n-3 PUFAs-enriched diet.

CONCLUSION

Our results suggest a potential relevant role of CORT/ssts and ghrelin systems in regulating PBMCs response to nutrient intake, which could help to explain the positive effects of n-3 PUFAs-enriched diets in reducing the inflammatory response.

Increased circulating obestatin in patients with chronic obstructive pulmonary disease

Background

Some peptides, which regulate the metabolic balance, are thought to play important roles in nutritional disorders and systemic inflammation in COPD. Treatment of rats with obestatin decreased body-weight gain. Obestatin was also found to be correlated with inflammation in rheumatoid arthritis. The aims of this study were to investigate the level of circulating obestatin in COPD and to analyze the relationship among obestatin and nutritional status, and systemic inflammation.

Methods

32 COPD patients with BMI less than 20 kg/m² and 22 normal controls were included. Body composition was estimated using “foot-to-foot” BIA technology. Circulating obestatin was determined with enzyme-linked immunosorbent assay. Pulmonary function, TNF-α and C reactive protein were also measured.

Results

The level of circulating obestatin was higher in COPD with underweight than that in normal control (5562.75 ± 3435.43 pg/ml in COPD, 3663.90 ± 2313.95 pg/ml in controls, p = 0.028). BMI, Waist circumference, hip circumference, bodyFAT and FAT% in COPD group were lower than those in normal control. Positive correlation was found among circulating C reactive protein, TNF-α and obestatin. There was no significant correlation among BMI, pulmonary function and obestatin.

Conclusions

This study shows that circulating obestatin is higher in underweight COPD patients, and positively correlated to systemic inflammation, but not to nutritional status.

A link between FTO, ghrelin, and impaired brain food-cue responsivity

Polymorphisms in the fat mass and obesity-associated gene (FTO) are associated with human obesity and obesity-prone behaviors, including increased food intake and a preference for energy-dense foods. FTO demethylates N6-methyladenosine, a potential regulatory RNA modification, but the mechanisms by which FTO predisposes humans to obesity remain unclear. In adiposity-matched, normal-weight humans, we showed that subjects homozygous for the FTO "obesity-risk" rs9939609 A allele have dysregulated circulating levels of the orexigenic hormone acyl-ghrelin and attenuated postprandial appetite reduction. Using functional MRI (fMRI) in normal-weight AA and TT humans, we found that the FTO genotype modulates the neural responses to food images in homeostatic and brain reward regions. Furthermore, AA and TT subjects exhibited divergent neural responsiveness to circulating acyl-ghrelin within brain regions that regulate appetite, reward processing, and incentive motivation. In cell models, FTO overexpression reduced ghrelin mRNA N6-methyladenosine methylation, concomitantly increasing ghrelin mRNA and peptide levels. Furthermore, peripheral blood cells from AA human subjects exhibited increased FTO mRNA, reduced ghrelin mRNA N6-methyladenosine methylation, and increased ghrelin mRNA abundance compared with TT subjects. Our findings show that FTO regulates ghrelin, a key mediator of ingestive behavior, and offer insight into how FTO obesity-risk alleles predispose to increased energy intake and obesity in humans.

Gene expression of peripheral blood mononuclear cells as a tool in dietary intervention studies: What do we know so far?

Peripheral blood mononuclear cells (PBMCs) generally refer to monocytes and lymphocytes, representing cells of the innate and adaptive immune systems. PBMCs are a promising target tissue in the field of nutrigenomics because they seem to reflect the effects of dietary modifications at the level of gene expression. In this review, we describe and discuss the scientific literature concerning the use of gene expression at the mRNA level measured from PBMCs in dietary interventions studies conducted in humans. A search of literature was undertaken using PubMed (last assessed November 24, 2011) and 20 articles were selected for discussion. Currently, results from these studies showed that PBMCs seem to reflect liver environment and complement adipose tissue findings in transcriptomics. PBMC gene expression after dietary intervention studies can be used for studying the response of certain genes related to fatty acid and cholesterol metabolism, and to explore the response of dietary interventions in relation to inflammation. However, PBMC transcriptomics from dietary intervention studies have not resulted yet in clear confirmation of candidate genes related to disease risk. Use of microarray technology in larger well-designed dietary intervention studies is still needed for exploring PBMC potential in the field of nutrigenomics.

Effects of circuit resistance training intensity on the plasma ghrelin to obestatin ratios in healthy young women

BACKGROUND

Ghrelin and obestatin are orexigenic and anorexigenic peptides, respectively. It appears that an accurate balance between theses peptides is important for regulating energy homeostasis and body weight.

OBJECTIVES

The aim of this study was to identify the possible mechanisms by which circuit resistance training influences energy homeostasis and weight control.

PATIENTS AND METHODS

Twenty-seven female students with the mean age of 22 ± 1.54 years and mean body mass index (BMI) of 20.76 ± 1.86 kg/m(2) were selected and randomly divided into experimental and control groups. Subjects performed circuit resistance training with 40% and 80% of 1 repetition maximum (1RM) for 4 weeks. Total plasma ghrelin, obestatin, and glucose levels and the ghrelin to obestatin ratio were measured for all subjects before and after training.

RESULTS

One-way ANOVA tests showed that, the plasma ghrelin to obestatin ratio increased significantly in the 80% 1RM group (P < 0.05). Furthermore, a significant reduction of the plasma obestatin level was found in this group (P < 0.05).

CONCLUSIONS

It appears that an energy deficit caused by circuit resistance training in 80% of the 1RM group resulted in the ghrelin precursor being increasingly used for ghrelin production. Thus, obestatin secretion decreased and the ghrelin to obestatin ratio increased in order to stimulate food intake and lost energy resource consumption to eventually restore the energy balance in the body.

Genetic variants of ghrelin in metabolic disorders

An increasing understanding of the role of genes in the development of obesity may reveal genetic variants that, in combination with conventional risk factors, may help to predict an individual's risk for developing metabolic disorders. Accumulating evidence indicates that ghrelin plays a role in regulating food intake and energy homeostasis and it is a reasonable candidate gene for obesity-related co-morbidities. In cross-sectional studies low total ghrelin concentrations and some genetic polymorphisms of ghrelin have been associated with obesity-associated diseases. The present review highlights many of the important problems in association studies of genetic variants and complex diseases. It is known that population-specific differences in reported associations exist. We therefore conclude that more studies on variants of ghrelin gene are needed to perform in different populations to get deeper understanding on the relationship of ghrelin gene and its variants to obesity.

Association of ADIPOR2 gene variants with cardiovascular disease and type 2 diabetes risk in individuals with impaired glucose tolerance: the Finnish Diabetes Prevention Study

BACKGROUND

Adiponectin is an adipokine with insulin-sensitising and anti-atherogenic effects. Two receptors for adiponectin, ADIPOR1 and ADIPOR2, have been characterized that mediate effects of adiponectin in various tissues. We examined whether genetic variation in ADIPOR2 predicts the development of cardiovascular disease (CVD) and/or Type 2 Diabetes (T2DM) in individuals with impaired glucose tolerance (IGT) participating the Finnish Diabetes Prevention Study (DPS).

METHODS

CVD morbidity and mortality data were collected during a median follow-up of 10.2 years (range 1-13 years) and conversion from IGT to T2DM was assessed during a median follow-up of 7 years (range 1-11 years). Altogether eight SNPs in the ADIPOR2 locus were genotyped in 484 participants of the DPS. Moreover, the same SNPs were genotyped and the mRNA expression levels of ADIPOR2 were determined in peripheral blood mononuclear cells and subcutaneous adipose tissue samples derived from 56 individuals participating in the Genobin study.

RESULTS

In the DPS population, four SNPs (rs10848554, rs11061937, rs1058322, rs16928751) were associated with CVD risk, and two remained significant (p = 0.014 for rs11061937 and p = 0.020 for rs1058322) when all four were included in the same multi-SNP model. Furthermore, the individuals homozygous for the rare minor alleles of rs11061946 and rs11061973 had increased risk of converting from IGT to T2DM. Allele-specific differences in the mRNA expression levels for the rs1058322 variant were seen in peripheral blood mononuclear cells derived from participants of the Genobin study.

CONCLUSIONS

Our results suggest that SNPs in the ADIPOR2 may modify the risk of CVD in individuals with IGT, possibly through alterations in the mRNA expression levels. In addition an independent genetic signal in ADIPOR2 locus may have an impact on the risk of developing T2DM in individuals with IGT.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT00518167.

Weight regain after a diet-induced loss is predicted by higher baseline leptin and lower ghrelin plasma levels

CONTEXT

Appetite-related hormones may play an important role in weight regain after obesity therapy.

OBJECTIVE

Our objective was to investigate the potential involvement of ghrelin, leptin, and insulin plasma levels in weight regain after a therapeutic hypocaloric diet.

DESIGN

A group of obese/overweight volunteers (49 women and 55 men; 35 ± 7 yr; 30.7 ± 2.4 kg/m(2)) followed an 8-wk hypocaloric diet (-30% energy expenditure) and were evaluated again 32 wk after treatment. Body weight as well as plasma fasting ghrelin, leptin, and insulin concentrations were measured at three points (wk 0, 8, and 32).

RESULTS

After the 8-wk hypocaloric diet, the average weight loss was -5.0 ± 2.2% (P < 0.001). Plasma leptin and insulin concentrations decreased significantly, whereas ghrelin levels did not markedly change. In the group regaining more than 10% of the weight loss, leptin levels were higher (P < 0.01), whereas ghrelin levels were lower (P < 0.05). No differences were observed in insulin levels. Weight regain at wk 32 was negatively correlated with ghrelin and positively associated with leptin levels at baseline (wk 0) and endpoint (wk 8). These outcomes showed a gender-specific influence, being statistically significant among men for ghrelin and between women for leptin. Moreover, a decrease in ghrelin after an 8-wk hypocaloric diet was related to an increased risk for weight regain (odds ratio = 3.109; P = 0.008) whereas a greater reduction in leptin (odds ratio = 0.141; P = 0.001) was related to weight-loss maintenance.

CONCLUSIONS

Subjects with higher plasma leptin and lower ghrelin levels at baseline could be more prone to regain lost weight, and hormones levels could be proposed as biomarkers for predicting obesity-treatment outcomes.

Peripheral blood mononuclear cells as a model to study the response of energy homeostasis-related genes to acute changes in feeding conditions

Peripheral blood mononuclear cells (PBMCs) are readily accessible biological material and a potential tissue source to discover novel biomarkers of response to environmental exposures including nutrition. We analyzed whether PBMCs could reflect molecular changes that take place in response to different feeding conditions in key organs/tissues involved in energy homeostasis. We studied energy balance-related genes whose expression was altered in normoweight (control) rats and in diet-induced (cafeteria) obese rats in response to ad libitum feeding, 14-h fasting, and 6-h refeeding after fasting, using whole-genome microarray analysis. In PBMCs, the expression of the genes central to energy metabolism was altered by the feeding conditions. The number of affected genes was 75 in the control rats, but only 23 in the cafeteria obese rats. Most of these genes play a role in metabolic pathways regulated by nutritional changes, such as lipid metabolism (the metabolic pathway mainly reflected in blood cells), carbohydrate metabolism, central energy metabolism, respiratory chain/mitochondrial ATPase system, and food intake regulation. Importantly, our results showed a similar behavior to that of the mesenteric white adipose tissue. In conclusion, metabolic adaptations to acute changes in feeding conditions are reflected in the expression of genes central to energy homeostasis in PBMCs of normoweight rats, while response is impaired in cafeteria obese animals. The lower number of genes affected in obese animals indicates impaired nutritional regulation. PBMCs appear as a suitable potential model to characterize metabolic adaptations to food intake and body weight maintenance in experimental animals. These findings may also inform the development of future peripheral tissue models in the emerging field of clinical nutrigenomics.

Acute circuit-resistance exercise increases expression of lymphocyte agouti-related protein in young women

Exercise-induced leukocytosis and lymphocytosis is accompanied by up-regulation and down-regulation of hundreds of genes in white blood cells (WBCs). Agouti-related protein (AgRP) is an orexigenic peptide secreted predominantly from the arcuate nucleus in the hypothalamus. AgRP affects feeding behavior and plays a role in energy and glucose homeostasis and adiposity. The purpose of the study was to determine effects of circuit resistance exercise (CRE) (9 exercises, 25 s per exercise) at different intensities on peripheral blood lymphocyte (PBL) AgRP mRNA expression and its concentrations in lymphocytes and plasma. Twenty-five young female college students were randomly divided into five groups: control, 40% 1-repetition maximum (1-RM), 60% 1-RM, 80% 1-RM and combined (40 + 60 + 80% 1-RM) loads. Peripheral blood mononuclear cells were isolated by a lymphocyte density gradient centrifugation method for AgRP mRNA expression. Lymphocyte ATP, glycogen, AgRP, growth hormone (GH), and plasma AgRP, GH and glucose concentrations were measured. CRE increased AgRP mRNA lymphocyte expression significantly ( P < 0.0001) at all intensities. A higher and significant ( P < 0.01) increase was found in the 60% 1-RM group when compared with the other groups. The CRE-induced lymphocyte AgRP expression was accompanied by elevations in plasma AgRP, glucose and GH levels as well as higher WBCs, lymphocytes and neutrophil counts. Lymphocyte AgRP and GH concentrations were significantly reduced ( P < 0.05). Lymphocyte ATP content was unchanged and glycogen was reduced in the combined group but not in the other groups. Data indicate that AgRP mRNA is expressed in PBLs and that CRE increases its expression. Data also reveal that the expression of AgRP was accompanied with higher plasma AgRP and GH concentrations. Findings suggest that AgRP may provide an important signal in the immune environment and that the lymphocyte may be considered as an extra-hypothalamic source of plasma AgRP following exercise stress.

Influence of ghrelin gene polymorphisms on hypertension and atherosclerotic disease

Ghrelin is involved in several metabolic and cardiovascular processes. Recent evidence suggests its involvement in blood pressure regulation and hypertension. The aim of the study was to determine associations of single-nucleotide polymorphisms (SNPs) and haplotypes of the ghrelin gene (GHRL) with hypertension and atherosclerotic disease. Six GHRL SNPs (rs27647, rs26802, rs34911341, rs696217, rs4684677 and a -473G/A (with no assigned rsID)) were investigated in a sample of 1143 hypertensive subjects and 1489 controls of Caucasian origin. Both single-locus and haplotype association analyses were performed. In single-locus analyses, only the non-synonymous rs34911341 was associated with hypertension (odds ratio (OR)=1.95 (95% confidence interval (CI): 1.26-3.02), P=0.003). Six common haplotypes with frequency >1% were inferred from the studied GHRL SNPs, and their frequency distribution was significantly different between hypertensive subjects and controls (chi(2)=12.96 with 5 d.f. (degree of freedom), P=0.024). The effect of rs26802 was found to be significantly (P=0.017) modulated by other GHRL SNPs, as its C allele conferred either an increased risk (OR=1.30 (1.08-1.57), P=0.005) or a decreased risk (OR=0.50 (0.23-1.06), P=0.07) of hypertension according to the two different haplotypes on which it can be found. No association of GHRL SNPs or haplotypes with atherosclerotic disease was observed. In conclusion, we observed statistical evidence for association between GHRL SNPs and risk of hypertension.

Ghrelin vaccination decreases plasma MCP-1 level in LDLR(-/-)-mice

Ghrelin is a novel peptide hormone having growth hormone releasing activity and many endocrine and metabolic functions. In rats and pigs, ghrelin immunizations have recently been shown to induce an antibody response against ghrelin simultaneously with a decrease in body weight gain. Our aim was to test the role of ghrelin immunization on atherosclerosis and weight gain in mice. LDLR(-/-)-mice (n=36) were immunized with ghrelin-PADRE, PADRE alone and PBS and then placed on a high fat diet for 22 weeks. Weight gain and food intake were followed throughout the study. Acylated and total ghrelin, cytokines and MCP-1 were analyzed from plasma using commercial kits. Stomach ghrelin was assessed using qRT-PCR and immunohistochemistry. Atherosclerosis was determined from aorta and cross-sections at the end of study. Mice immunized with ghrelin-PADRE developed high plasma IgG titers to ghrelin simultaneously with a significant increase in plasma acylated and total ghrelin levels. Plasma MCP-1 levels decreased in mice immunized with ghrelin-PADRE compared to mice immunized with PADRE and PBS. There were no differences in atherosclerosis determined from aorta and cross-sections as well as in body weights and food intake in LDLR(-/-)-mice between the different immunization groups. Our data indicates that ghrelin-PADRE vaccination induces a strong exclusive IgG response to ghrelin and increases plasma acylated and total ghrelin levels in mice. Ghrelin vaccination decreases plasma MCP-1 levels even though no effects on developing signs of atherosclerosis or weight gain in mice were observed.

Association of sequence variations in the gene encoding insulin-like growth factor binding protein 5 with adiponectin

BACKGROUND

Insulin-like growth factor binding protein 5 (IGFBP5) binds to IGF and thus modulates IGF signaling pathway. We have shown earlier that the IGFBP5 gene was downregulated in the adipose tissue after 12-week carbohydrate diet with low insulinemic response.

OBJECTIVE

The aim was to examine the putative contribution of genetic variation of the IGFBP5 gene to the characteristics of metabolic syndrome and incidence of type 2 diabetes (T2DM) in the Finnish Diabetes Prevention Study (DPS).

METHODS

DPS is a longitudinal study where 522 subjects with impaired glucose tolerance were randomized to either lifestyle intervention group or control group. DNA was available from 507 subjects (mean body mass index (BMI) 31.2+/-4.5 kg/m(2), age 55+/-7 years). The eight single-nucleotide polymorphisms (SNPs) were selected from HapMap database and genotyped by Taqman allelic discrimination protocol. The main results were confirmed in a larger cross-sectional study population (METSIM). In addition, the gene expression of IGFBP5 was studied in two previously published study populations (FUNGENUT and GENOBIN) of 124 subjects with insulin resistance (BMI 32.2+/-3.5 kg/m(2), age 57.7+/-7.4 years).

RESULTS

Three out of eight IGFBP5 markers (rs9341234, rs3276 and rs11575134) were significantly associated with circulating adiponectin concentrations in men. Furthermore, mRNA expression studies of subcutaneous adipose tissue showed that mRNA concentrations of IGFBP5 correlated with adiponectin concentrations in all subjects and in women. None of the IGFBP5 SNPs were associated with T2DM.

CONCLUSIONS

Our findings show that IGFBP5 has a gender-specific association with adiponectin, which may modulate the development of metabolic syndrome.