Leucine 7 to proline 7 polymorphism in the preproneuropeptide Y is associated with proteinuria, coronary heart disease, and glycemic control in type 1 diabetic patients

Neuropeptide Y gene variants in obesity, dietary intake, blood pressure, lipid and glucose metabolism: A longitudinal birth cohort study

OBJECTIVE

Neuropeptide Y affects several physiological functions, notably appetite regulation. We analysed the association between four single nucleotide polymorphisms (SNP) in the NPY gene (rs5574, rs16147, rs16139, rs17149106) and measures of obesity, dietary intake, physical activity, blood pressure, glucose and lipid metabolism from adolescence to young adulthood.

METHODS

The sample included both birth cohorts of the Estonian Children Personality Behaviour and Health Study at ages 15 (n = 1075 with available complete data), 18 (n = 913) and 25 (n = 926) years. Linear mixed-effects regression models were used for longitudinal association between NPY SNP-s and variables of interest. Associations at ages 15, 18 and 25 were analysed by ANOVA.

RESULTS

Rs5574 CC-homozygotes had a greater increase per year in waist-to-hip ratio (WHR) and a smaller decrease in daily energy intake and carbohydrate intake from age 15-25 years; fasting glucose and cholesterol were higher in rs5574 CC-homozygotes. Rs16147 TT-homozygotes had higher body weight and a greater increase in sum of 5 skinfolds, waist circumference, WHR and waist-to-height ratio; however, they had lower carbohydrate intake throughout the observation period. Rs16147 TT-homozygotes and both rs16139 and rs17149106 heterozygotes had higher triglyceride levels. All NPY SNP-s were associated with blood pressure: rs5574 TT-and rs16147 CC-homozygotes had a smaller increase in diastolic blood pressure, while rs16139 and rs17149106 heterozygous had lower blood pressure throughout the study.

CONCLUSION

Variants of the NPY gene were associated with measures of obesity, dietary intake, glucose and lipid metabolism and blood pressure from adolescence to young adulthood.

A role for NPY-NPY2R signaling in albuminuric kidney disease

Neuropeptide Y (NPY) is implicated in many pathological conditions including obesity, diabetes, and insulin resistance. However, a pathogenic role of NPY in kidney disease has not been described. We found that NPY is produced by the podocyte in the glomerulus, and this production decreases in renal disease, in contrast to an increase in circulating NPY levels. In the glomerulus, NPY signals via the NPY receptor 2 (NPY2R) and modulates PI3K, MAPK, and NFAT signaling, along with RNA processing and cell migration and, if prolonged, predicted nephrotoxicity. The pharmacological inhibition of NPY-NPY2R signaling also protected against albuminuria and kidney disease in a mouse model of glomerulosclerosis, suggesting that inhibiting this pathway may be therapeutically beneficial in the prevention of kidney disease.

Albuminuria is an independent risk factor for the progression to end-stage kidney failure, cardiovascular morbidity, and premature death. As such, discovering signaling pathways that modulate albuminuria is desirable. Here, we studied the transcriptomes of podocytes, key cells in the prevention of albuminuria, under diabetic conditions. We found that Neuropeptide Y (NPY) was significantly down-regulated in insulin-resistant vs. insulin-sensitive mouse podocytes and in human glomeruli of patients with early and late-stage diabetic nephropathy, as well as other nondiabetic glomerular diseases. This contrasts with the increased plasma and urinary levels of NPY that are observed in such conditions. Studying NPY-knockout mice, we found that NPY deficiency in vivo surprisingly reduced the level of albuminuria and podocyte injury in models of both diabetic and nondiabetic kidney disease. In vitro, podocyte NPY signaling occurred via the NPY2 receptor (NPY2R), stimulating PI3K, MAPK, and NFAT activation. Additional unbiased proteomic analysis revealed that glomerular NPY-NPY2R signaling predicted nephrotoxicity, modulated RNA processing, and inhibited cell migration. Furthermore, pharmacologically inhibiting the NPY2R in vivo significantly reduced albuminuria in adriamycin-treated glomerulosclerotic mice. Our findings suggest a pathogenic role of excessive NPY-NPY2R signaling in the glomerulus and that inhibiting NPY-NPY2R signaling in albuminuric kidney disease has therapeutic potential.

A Review of Single-Nucleotide Polymorphisms in Orexigenic Neuropeptides Targeting G Protein-Coupled Receptors

Many physiological pathways are involved in appetite, food intake, and the maintenance of energy homeostasis. In particular, neuropeptides within the central nervous system have been demonstrated to be critical signaling molecules for modulating appetite. Both anorexigenic (appetite-decreasing) and orexigenic (appetite-stimulating) neuropeptides have been described. The biological effects of these neuropeptides can be observed following central administration in animal models. This review focuses on single nucleotide polymorphisms (SNPs) in six orexigenic neuropeptides: agouti-related protein (AGRP), galanin, melanin concentrating hormone (MCH), neuropeptide Y (NPY), orexin A, and orexin B. Following a brief summary of the neuropeptides and their orexigenic activities, reports associating SNPs within the orexigenic neuropeptides to energy homeostasis, food intake, obesity, and BMI in humans are reviewed. Additionally, the NIH tool Variation Viewer was utilized to identify missense SNPs within the mature, biologically active neuropeptide sequences. For SNPs found through Variation Viewer, a concise discussion on relevant pharmacological structure-activity relationship studies for select SNPs is included. This review is meant to update reported orexigenic neuropeptide SNPs and demonstrate the potential utility of genomic sequence databases for finding SNPs that may result in altered receptor signaling for neuropeptide pathways associated with appetite.

Novel risk genes identified in a genome-wide association study for coronary artery disease in patients with type 1 diabetes

Background

Patients with type 1 diabetes are more at risk of coronary artery disease than the general population. Although evidence points to a genetic risk there have been no study investigating genetic risk factors of coronary artery disease specific to individuals with type 1 diabetes. To identify low frequency and common genetic variations associated with coronary artery disease in populations of individuals with type 1 diabetes.

Methods

A two-stage genome wide association study was conducted. The discovery phase involved the meta-analysis of three genome-wide association cohorts totaling 434 patients with type 1 diabetes and coronary artery disease (cases) and 3123 T1D individuals with no evidence of coronary artery disease (controls). Replication of the top association signals (p < 10⁻⁵) was performed in five additional independent cohorts totaling 585 cases and 2612 controls.

Results

One locus (rs115829748, located upstream of the MAP1B gene) reached the statistical threshold of 5 × 10⁻⁸ for genome-wide significance but did not replicate. Nevertheless, three single nucleotide polymorphisms provided suggestive evidence for association with coronary artery disease in the combined studies: CDK18 rs138760780 (OR = 2.60 95% confidence interval [1.75–3.85], p = 2.02 × 10⁻⁶), FAM189A2 rs12344245 (OR = 1.85 [1.41–2.43], p = 8.52 × 10⁻⁶) and PKD1 rs116092985 (OR = 1.53 [1.27–1.85], p = 1.01 × 10⁻⁵). In addition, our analyses suggested that genetic variations at the ANKS1A, COL4A2 and APOE loci previously found associated with coronary artery disease in the general population could have stronger effects in patients with type 1 diabetes.

Conclusions

This study suggests three novel candidate genes for coronary artery disease in the subgroup of patients affected with type 1 diabetes. The detected associations deserve to be definitively validated in additional epidemiological studies.

Electronic supplementary material

The online version of this article (10.1186/s12933-018-0705-0) contains supplementary material, which is available to authorized users.

The Proline 7 Substitution in the Preproneuropeptide Y Is Associated with Higher Hepatic Lipase Activity In Vivo

Hepatic lipase (HL) functions as a lipolytic enzyme that hydrolyzes triglycerides and phospholipids present in circulating plasma lipoproteins. Plasma HL activity is known to be regulated by hormonal and metabolic factors, but HL responsiveness to insulin as well as its role in modulating atherosclerotic risk is still controversial. We investigated on the influence of a known polymorphism in the neurotransmitter neuropeptide Y (NPY) on HL activity in two different cohorts consisting of diabetic and nondiabetic patients. HL activity was 24% and 34% higher on nondiabetic and diabetic subjects in the presence of the 7Pro allele in NPY, respectively. The presence of the 7Pro allele was an independent predictor of HL activity in multivariate analyses in both cohorts. These data suggest a regulatory effect of NPY on HL activity. Among carriers of the 7Pro allele, we also found a statistically significant lower absolute number of infarctions compared to noncarriers (p < 0.05) and a nonsignificant trend towards less myocardial infarction in the 7Pro allele diabetic carriers (p = 0.085). In conclusion, the common 7Pro allele in NPY was associated with higher HL activity in nondiabetic and diabetic subjects and its presence seems to coincide with a lower frequency of certain cardiovascular events.

Association of Neuropeptide-Y (NPY) and Interleukin-1beta (IL1B), Genotype-Phenotype Correlation and Plasma Lipids with Type-II Diabetes

BACKGROUND

Neuropeptide Y (NPY) is known to play a role in the regulation of satiety, energy balance, body weight, and insulin release. Interleukin-1beta (IL1B) has been associated with loss of beta-cell mass in type-II diabetes (TIID).

OBJECTIVES

The present study attempts to investigate the association of NPY exon2 +1128 T/C (Leu7Pro; rs16139), NPY promoter -399 T/C (rs16147) and IL1B -511 C/T (rs16944) polymorphisms with TIID and their correlation with plasma lipid levels, BMI, and IL1B transcript levels.

METHODS

PCR-RFLP was used for genotyping these polymorphisms in a case-control study involving 558 TIID patients and 1085 healthy age-matched controls from Gujarat. Linkage disequilibrium and haplotype analysis of the NPY polymorphic sites were performed to assess their association with TIID. IL1B transcript levels in PBMCs were also assessed in 108 controls and 101 patients using real-time PCR.

RESULTS

Our results show significant association of both structural and promoter polymorphisms of NPY (p<0.0001 and p<0.0001 respectively) in patients with TIID. However, the IL1B C/T polymorphism did not show any association (p = 0.3797) with TIID patients. Haplotype analysis revealed more frequent association of CC and CT haplotypes (p = 3.34 x 10-5, p = 6.04 x 10-9) in diabetics compared to controls and increased the risk of diabetes by 3.02 and 2.088 respectively. Transcript levels of IL1B were significantly higher (p<0.0001) in patients as compared to controls. Genotype-phenotype correlation of IL1B polymorphism did not show any association with its higher transcript levels. In addition, NPY +1128 T/C polymorphism was found to be associated with increased plasma LDL levels (p = 0.01).

CONCLUSION

The present study provides an evidence for a strong correlation between structural and promoter polymorphisms of NPY gene and upregulation of IL1B transcript levels with susceptibility to TIID and altering the lipid metabolism in Gujarat population.

Neuropeptide Y reduces the expression of PLCB2, PLCD1 and selected PLC genes in cultured human endothelial cells

Endothelial cells (EC) are the first elements exposed to mediators circulating in the bloodstream, and react to stimulation with finely tuned responses mediated by different signal transduction pathways, leading the endothelium to adapt. Neuropeptide Y (NPY), the most abundant peptide in heart and brain, is mainly involved in the neuroendocrine regulation of the stress response. The regulatory roles of NPY depend on many factors, including its enzymatic processing, receptor subtypes and related signal transduction systems, including the phosphoinositide (PI) pathway and related phospholipase C (PI-PLC) family of enzymes. The panel of expression of PI-PLC enzymes differs comparing quiescent versus differently stimulated human EC. Growing evidences indicate that the regulation of the expression of PLC genes, which codify for PI-PLC enzymes, might act as an additional mechanism of control of the PI signal transduction pathway. NPY was described to potentiate the activation of PI-PLC enzymes in different cell types, including EC. In the present experiments, we stimulated human umbilical vein EC using different doses of NPY in order to investigate a possible role upon the expression PLC genes. NPY reduced the overall transcription of PLC genes, excepting for PLCE. The most significant effects were observed for PLCB2 and PLCD1, both isoforms recruited by means of G-proteins and G-protein-coupled receptors. NPY behavior was comparable with other PI-PLC interacting molecules that, beside the stimulation of phospholipase activity, also affect the upcoming enzymes' production acting upon gene expression. That might represent a mode to regulate the activity of PI-PLC enzymes after activation.

Systemic treatment with neuropeptide Y receptor Y1-antagonist enhances atherosclerosis and stimulates IL-12 expression in ApoE deficient mice

AIMS

Neuropeptide Y (NPY) and Y1 receptors are involved in the mechanisms related to the development of atherosclerosis. We investigated the effects of systemically given NPY and its receptor Y1-antagonist on the development of atherosclerosis and associated inflammatory molecules in ApoE(-/-) mice during high-fat diet.

METHODS

Five weeks old ApoE(-/-) were fed atherogenic high cholesterol diet for 8weeks. The mice were injected with two doses of NPY (50 or 100μg/kg) or Y1 receptor antagonist BIBP3226 (100μg/kg) or vehicle intraperitoneally for 8weeks. Atherosclerosis lesion areas in aortic arch and descending aortas were determined, inflammatory molecules and NPY were determined in aortic wall, spleen, liver or in serum.

RESULTS

Neuropeptide Y1 receptor antagonist, BIBP3226 (100μg/kg) increased atherosclerotic lesion areas compared to vehicle in descending aortas in ApoE(-/-) mice (p=0.021). The expression levels of macrophage-derived cytokine, interleukin-12 (IL-12) in spleens and livers were 8-fold increased with BIBP3226 (p=0.006 and p=0.003, respectively) as determined by RT-qPCR. Cholesterol levels in serum correlated positively with VCAM-1 expression (p=0.003) and negatively with NPY expression (p=0.044) in aortic wall in mice treated with BIBP 3226.

CONCLUSIONS

The results indicate that systemic treatment with Y1-antagonist enhances atherosclerosis development in ApoE deficient mice by triggering an overwhelming IL-12 production. The findings are highly valuable for evaluation of the development potential of Y1 ligands for therapeutics to treat or prevent atherosclerosis.

Association between neuropeptide Y gene polymorphisms and alcohol dependence: a case-control study in two independent populations

BACKGROUND

Alcohol dependence is a chronic, progressive neurobiological brain disorder. Previous research reported an inverse association between ethanol drinking and cerebral neuropeptide Y (NPY) levels. There are conflicting results of studies on NPY gene polymorphisms in association with alcohol dependence in humans.

METHODS

To assess the role of the NPY gene in alcohol dependence, we genotyped three polymorphisms--in a sample of 195 subjects from the Kota population (80 alcohol dependence and 115 controls) and 141 subjects from the Badaga population (80 alcohol dependence and 61 controls). Phenotype was defined based on the DSM-IV criteria. Genotyping was performed using sequencing. Association of the NPY gene with alcohol dependence was tested by using logistic regression and haplotype analyses and linkage disequilibrium.

RESULTS

All three polymorphisms were found to be in the Hardy-Weinberg equilibrium in both populations. The results of our study reveal a significant association between G1258A and alcohol dependence in both the Kota and Badaga populations. The linkage disequilibrium between the markers is not strong or significant. Haplotype analysis also did not show significant association between the NPY gene and alcohol dependence.

CONCLUSION

These data support the hypothesis that alcohol dependence is influenced by the NPY G1258A polymorphism in Indian populations.

Neuropeptide Y in the noradrenergic neurons induces the development of cardiometabolic diseases in a transgenic mouse model

Neuropeptide Y (NPY) is a neuropeptide widely expressed in the brain and a peptide transmitter of sympathetic nervous system (SNS) co-released with noradrenaline (NA) in prolonged stress. Association of a gain-of-function polymorphism in the human NPY gene with dyslipideamia, diabetes and vascular diseases suggests that increased NPY plays a role in the pathogenesis of the metabolic syndrome in humans. In the hypothalamus, NPY plays an established role in the regulation of body energy homeostasis. However, the effects of NPY elsewhere in the brain and in the SNS are less explored. In order to understand the role of NPY co-expressed with NA in the sympathetic nerves and brain noradrenergic neurons, a novel mouse model overexpressing NPY in noradrenergic neurons was generated. The mouse displays metabolic defects such as increased adiposity, hepatosteatosis, and impaired glucose tolerance as well as stress-related hypertension and increased susceptibility to vascular wall hypertrophy. The mouse phenotype closely reflects the findings of the several association studies with human NPY gene polymorphisms, and fits with the previous work on the effects of stress-induced NPY release on metabolism and vasculature. Thus, in addition of promoting feeding and obesity in the hypothalamus, NPY expressed in the noradrenergic neurons in the brain and in the SNS induces the development of cardiometabolic diseases.

High frequency of Neuropeptide Y Leu7Pro polymorphism in an Iranian population and its association with coronary artery disease

OBJECTIVE

Neuropeptide Y (NPY), a 36-amino acid peptide, is widely expressed in the central and peripheral nervous systems as well as in the heart. A relationship has been reported between NPY gene variants and coronary artery disease (CAD) in some populations. However, there are few data on the NPY gene polymorphism and CAD in the Persian population. In the current study we have investigated the relationship between the NPY Leu7Pro polymorphism and CAD within a population from Iran.

METHODS

A total of 1061 subjects were recruited; 609 patients and 452 healthy subjects. Four hundred and twenty eight of the patients had >50% stenosis; with the remaining 181 patients having <50% stenosis based on angiography. Angiography positive patients were divided into three groups: those with single (n=115), double (n=140), and triple vessel (n=173) disease. DNA analysis for the Leu7Pro polymorphism was performed using a PCR-RFLP technique.

RESULTS

A significantly higher frequency of the Leu7Pro genotype was observed in CAD patients compared with the control group (P<0.05). Patients with the Pro7 had significantly higher values for weight (P=0.027), BMI (P=0.001), hip circumference (P=0.003) and prevalence of diabetes mellitus (P=0.018) but reduced prevalence of a history of myocardial infarction (P=0.017).

CONCLUSIONS

The frequency of Leu7Pro polymorphism of NPY was 5.9% in our Iranian population; higher than reported for other Asian populations. The Leu7Pro polymorphism was associated with CAD in an Iranian population.

Inflammatory effects of blood leukocytes: association with vascular function in neuropeptide Y proline 7-genotyped type 2 diabetes patients

OBJECTIVE

We investigated the associations of inflammatory blood cell activation with vascular parameters in patients with type 2 diabetes to elucidate the possible mechanisms of accelerated atherosclerosis observed in subjects with the Leucine 7 to Proline 7 polymorphism (Leu7Pro) in the neuropeptide Y (NPY).

METHODS

Our study included 31 Caucasian patients with type 2 diabetes; 12 of them had the Leu7Pro7 (heterozygous), and 19 had the Leu7Leu7 (wild type) genotype. Vascular parameters were determined by ultrasound methods. Leukocyte analyses were performed from blood samples using flow cytometry. NPY concentrations were determined in plasma.

RESULTS

The amount of platelet-granulocyte complexes was positively correlated with NPY concentration (p=0.008) and carotid intima-media thickness (p=0.035) in the Leu7Pro7 group. Interferon gamma (IFN-γ) expression in monocytes correlated negatively with brachial artery flow-mediated dilatation also in the Leu7Pro7 group (p=0.037). The expression of tissue factor on monocytes correlated negatively with brachial artery diameter in the Leu7Pro7 patients as well (p=0.019).

CONCLUSION

The results indicate significant associations between inflammatory cell activation in blood and vascular atherosclerosis in genetically prone subjects, and provide possible mechanistic information about the role of NPY and the Leu7Pro polymorphism in the development of atherosclerosis.

No association of the neuropeptide Y (Leu7Pro) and ghrelin gene (Arg51Gln, Leu72Met, Gln90Leu) single nucleotide polymorphisms with eating disorders

BACKGROUND

Genetic factors likely contribute to the biological vulnerability of eating disorders.

AIMS

Case-control association study on one neuropeptide Y gene (Leu7Pro) polymorphism and three ghrelin gene (Arg51Gln, Leu72Met and Gln90Leu) polymorphisms.

METHODS

114 eating disorder patients (46 with anorexia nervosa, 30 with bulimia nervosa, 38 with binge eating disorder) and 164 healthy controls were genotyped.

RESULTS

No differences were detected between patients and controls for any of the four polymorphisms in allele frequency and genotype distribution (P > 0.05). Allele frequencies and genotypes had no significant influence on body mass index (P > 0.05) in eating disorder patients.

CONCLUSION

Positive findings of former case-control studies of associations between ghrelin gene polymorphisms and eating disorders could not be replicated. Neuropeptide Y gene polymorphisms have not been investigated in eating disorders before.

A polymorphism in the angiotensin II type 1 receptor gene has different effects on the risk of diabetic nephropathy in men and women

BACKGROUND

The etiology of diabetic nephropathy depends partly on genetic factors. Elevated systemic and intraglomerular blood pressure and glomerular filtration rate, partly regulated by the renin-angiotensin system, increase the risk of diabetic nephropathy.

METHODS

The present case-control study investigated the association of the rs5186 polymorphism, in the angiotensin II type 1 receptor gene (AGTR1), with diabetic nephropathy. The study included 3561 patients with type 1 diabetes from Denmark, Finland, France and Sweden. Microalbuminuria was defined as albumin excretion rate (AER) ≥20 to <200 μg/min or albumin concentration ≥30 to <300 mg/l (n=707), macroalbuminuria was defined as AER≥200 μg/min or ≥300 mg/l (n=1546), and patients with renal replacement therapy were also included in this group. The controls had >15 years diabetes duration, AER <20 μg/min or <30 mg/l, and no antihypertensive treatment (n=1308).

RESULTS

AA genotype of the rs5186 polymorphism significantly increased the risk of diabetic nephropathy in male patients, OR=1.27 (95% CI=1.02-1.58), P=0.03, adjusted for age at diabetes onset, HbA1c, diabetes duration, smoking and country of origin. Among the women, there were no significant associations between rs5186 and diabetic nephropathy, OR=0.89 (0.71-1.11), P=0.30.

CONCLUSION

We conclude that the AGTR1 gene may be associated with increased risk of diabetic nephropathy in men with type 1 diabetes.

Association between testosterone, estradiol and sex hormone binding globulin levels in men with type 1 diabetes with nephropathy

Male sex is a risk factor for development and progression of diabetic nephropathy; however, the relationship between sex hormone levels and diabetic nephropathy in type 1 diabetic men is unknown. This was a prospective follow-up study as part of the nationwide Finnish Diabetic Nephropathy (FinnDiane) Study; 297 patients were followed for 5.9+/-1.5 years. Serum total testosterone (Tt) and estradiol (Te), calculated free testosterone (cFt) and estradiol (cFe) and sex hormone binding globulin were measured at baseline and correlated with urinary albumin excretion rate, estimated glomerular filtration rate and markers of metabolic syndrome. Diabetes without renal disease was associated with decreased Tt (p<0.001), Te (p<0.001) and cFt (p=0.001) levels compared with healthy non-diabetic men. With progression of renal disease from micro- to macroalbuminuria, this decrease in serum Tt was even more pronounced. Cox regression showed that cFt and cFe were independent predictors of the progression from macroalbuminuria to end-stage renal disease. Our study shows that men with type 1 diabetes exhibit dysregulated sex hormone levels, which is most pronounced in men with progressive renal disease, suggesting that sex hormones may play a role in the pathogenesis of diabetic nephropathy associated with type 1 diabetes.

Neuropeptide Y gene polymorphisms are not associated with obesity in a South Indian population

BACKGROUND/OBJECTIVES

Neuropeptide Y (NPY) gene has been shown to have a critical role in the regulation of satiety, reproduction, central endocrine and cardiovascular systems. Among the primary functions associated with NPY are its acute effects on feeding behavior and energy expenditure. The aim of this study is to evaluate the relationship between obesity and NPY gene polymorphisms in a South Indian Population.

SUBJECTS/METHODS

Three polymorphisms in NPY gene (Leu7Pro, Ser50Ser and A7735G) were analyzed in 263 individuals of an endogamous Kota population. On the basis of body mass index (BMI), they were divided into two groups. Associations were tested using logistic regression and haplotype analyses and linkage disequilibrium (LD).

RESULTS

There was no evidence of deviation from Hardy-Weinberg equilibrium. Logistic regression analysis did not reveal significant association with obesity and NPY single-nucleotide polymorphisms (SNPs) in the present study. All three SNPs were in weak LD with low r (2) values. Haplotype analysis also did not yield significant association between NPY gene and obesity (global P=0.756).

CONCLUSIONS

Our study did not validate the association between previously implicated SNPs in NPY gene and obesity in an Indian population. Population-specific validation of putative associations has far reaching implications for the future personal genomics medicine applications.

PreproNPY Pro7 protects against depression despite exposure to environmental risk factors

BACKGROUND

There is extensive evidence, from both clinical cases and rodent models, for reduced levels of the widely expressed neuropeptide Y (NPY) in anxiety and depressive disorders. The rare allele of the Leu7Pro polymorphism in the signal peptide of preproNPY has been associated with higher processing into mature NPY, and higher NPY levels in plasma and cerebrospinal fluid. The Pro7 allele was proposed to protect against depression in a small Swedish clinical sample (Heilig M., Zachrisson O., Thorsell A., Ehnvall A., Mottagui-Tabar S., Sjögren M., Asberg M., Ekman R., Wahlestedt C., Agren H., 2004. Decreased cerebrospinal fluid neuropeptide Y (NPY) in patients with treatment refractory unipolar major depression: preliminary evidence for association with preproNPY gene polymorphism. J. Psychiatr. Res. 38, 113-121).

METHOD

Leu7Pro was analyzed in a large well-characterized longitudinal population-based sample of adult Swedes with data on life situation and life history, including 461 with depression diagnosis, 157 with anxiety diagnosis and 1514 healthy individuals with no symptom of psychopathology.

RESULTS

Pro7 was rarer in depression cases than in healthy individuals (OR=2.7; P=0.0004). The protective effect of Pro7 was similar despite exposure to known environmental vulnerability factors. Pro7 appeared with similar effect size in those with an anxiety diagnosis, but this was not statistically significant (OR=2.3; P=0.06).

LIMITATION

The size of the anxiety sample and possibly some recall bias of childhood conditions.

CONCLUSION

Pro7 allele of preproNPY protected against depression among Swedes. Pro7 is not common, but was found to exert its protective effect also in an environment-induced vulnerable state. This supports a protective effect of NPY in line with previous reports suggesting anxiolytic-like and antidepressant-like effects of NPY.

Neuropeptide Y gene polymorphisms confer risk of early-onset atherosclerosis

Neuropeptide Y (NPY) is a strong candidate gene for coronary artery disease (CAD). We have previously identified genetic linkage to familial CAD in the genomic region of NPY. We performed follow-up genetic, biostatistical, and functional analysis of NPY in early-onset CAD. In familial CAD (GENECARD, N = 420 families), we found increased microsatellite linkage to chromosome 7p14 (OSA LOD = 4.2, p = 0.004) in 97 earliest age-of-onset families. Tagged NPY SNPs demonstrated linkage to CAD of a 6-SNP block (LOD = 1.58-2.72), family-based association of this block with CAD (p = 0.02), and stronger linkage to CAD in the earliest age-of-onset families. Association of this 6-SNP block with CAD was validated in: (a) 556 non-familial early-onset CAD cases and 256 controls (OR 1.46-1.65, p = 0.01-0.05), showing stronger association in youngest cases (OR 1.84-2.20, p = 0.0004-0.09); and (b) GENECARD probands versus non-familial controls (OR 1.79-2.06, p = 0.003-0.02). A promoter SNP (rs16147) within this 6-SNP block was associated with higher plasma NPY levels (p = 0.04). To assess a causal role of NPY in atherosclerosis, we applied the NPY1-receptor-antagonist BIBP-3226 adventitially to endothelium-denuded carotid arteries of apolipoprotein E-deficient mice; treatment reduced atherosclerotic neointimal area by 50% (p = 0.03). Thus, NPY variants associate with atherosclerosis in two independent datasets (with strong age-of-onset effects) and show allele-specific expression with NPY levels, while NPY receptor antagonism reduces atherosclerosis in mice. We conclude that NPY contributes to atherosclerosis pathogenesis.

Type 1 diabetes, hyperglycaemia, and the heart

Type 1 diabetes is associated with a substantially increased risk of cardiovascular disease that might not always be appreciated in view of the fairly young age of patients with this condition. In fact, in type 1 diabetes, the heart is subject to a variety of pathological insults, including accelerated atherosclerosis, cardiac autonomic neuropathy, and possibly intrinsic cardiomyopathy. Although the relation between hyperglycaemia and microvascular complications has been well established, a direct effect of hyperglycaemia on cardiovascular disease in type 1 diabetes has long been debated. More recently, several studies, most notably the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications, have clarified this issue and provided conclusive evidence that hyperglycaemia is indeed a mediator of cardiovascular risk in type 1 diabetes and that intensive diabetes therapy can reduce cardiovascular disease outcomes. We review current concepts in type 1 diabetes and the heart, focusing on recent insights into the central role of hyperglycaemia.

Leucine 7 to proline 7 polymorphism in the neuropeptide Y gene and changes in serum lipids during a family-based counselling intervention among school-aged children with a family history of CVD

OBJECTIVE

To compare whether serum lipids and their changes during a health education intervention are associated with the Leu7Pro polymorphism in the signal peptide part of neuropeptide Y (NPY) in children with normal weight and in those with overweight.

DESIGN

An intervention study.

SETTING

A family-based intervention of risk factors for prevention of CHD in Finland.

SUBJECTS

Subjects were 443 children with a family history of CVD participating in family-based health education. The children were divided into two groups according to NPY genotype: children with Leu7/Pro7 or Pro7/Pro7 genotype (n 50) and children with Leu7/Leu7 genotype (n 393). The final sample of the follow-up study included 353 (80 %) children (Pro7 allele carriers, n 43; Leu7/Leu7, n 310).

RESULTS

At baseline, the Leu7Pro polymorphism was not associated with serum lipid values after adjustment for body weight in boys or girls. There was a significant interaction of NPY genotype group by time and body weight (P = 0.043 for three-way interaction: time x NPY genotype x body weight) in LDL-cholesterol (LDL-C) concentration among boys. LDL-C decreased among boys with normal weight in both NPY groups and in overweight boys with the Leu7/Leu7 genotype, whereas it increased in overweight boys with the Pro7 allele. Two-way interaction (time x NPY genotype) showed no significant differences in changes of serum lipids between the NPY genotype groups among boys or girls.

CONCLUSIONS

The Leu7Pro polymorphism may be associated with dietary response to LDL-C concentration in overweight boys with a family history of early-onset CVD.

Distribution of neuropeptide Y Leu7Pro polymorphism in patients with type 1 diabetes and diabetic nephropathy among Swedish and American populations

OBJECTIVE

The distribution of Leu7Pro polymorphism in the neuropeptide Y gene shows a geographical north to south gradient of decreasing frequency, suggesting that it may be a population-specific causal variant. This polymorphism is found to be associated with diabetic nephropathy (DN) and coronary heart disease in Finnish women with type 1 diabetes (T1D). The present study aims to evaluate the susceptibility of this polymorphism to the development of DN in two different populations.

DESIGN

One sample set consists of 174 (females 98 and males 76) Swedish T1D patients with DN and 249 (females 132 and males 117) patients without DN. Another sample set includes 597 (females 356 and males 241) American T1D patients without DN and 577 (females 264 and males 313) patients with DN, who were descents of European Caucasians and were from the Genetics of Kidneys in Diabetes (GoKinD) Study.

METHODS

Genotyping of Leu7Pro polymorphism was performed by dynamic allele-specific hybridization.

RESULTS

The C allele frequencies of Leu7Pro polymorphism in T1D patients between Swedish and American GoKinD populations were significantly different (6.3 vs 4.0%; P=0.006). Particularly, the C allele frequency in Swedish female T1D patients with DN was significantly higher in comparison with T1D patients without DN (10.2 vs 4.2%; P=0.011, OR=2.614, 95% confidence intervals: 1.249-5.467). No significant association of this polymorphism with DN was observed in Swedish male T1D patients and the patients from GoKinD.

CONCLUSIONS

The present study provides further evidence that Leu7Pro polymorphism confers the susceptibility to the development of DN in Swedish female T1D patients.

Allelic variation in the NPY gene in 14 Indian populations

NPY is a 36-aminoacid peptide expressed in several areas of the nervous system. Neuropeptide Y (NPY) receptors represent a widely diffused system that is involved in the regulation of multiple biological functions. The human NPY gene is located in chromosome 7. The functional significance of coding Leu7Pro polymorphism in the signal peptide of preproNPY is known. Six hundred and fifty four individuals of 14 ethnic Indian populations were screened for three mutations in the NPY gene, including Leu7Pro. We found that the Pro7 frequencies among the studied populations were much higher than in previous studies from other parts of the world. The highest allele frequency of Pro7 was detected in the Kota population in the Nilgiri Hill region of south India, and this may reflect a founder event in the past or genetic drift. All populations followed the Hardy-Weinberg equilibrium for the assayed markers. A total of five haplotypes were observed, only two of which were found to occur with a high frequency in all populations. No linkage disequilibrium (LD) was observed across the tested alleles in any population with the exception of Leu7Pro and Ser50Ser in the Badaga population (chi(2) = 13.969; p = 0.0001).

A functional polymorphism in the manganese superoxide dismutase gene and diabetic nephropathy

Oxidative stress has been suggested to contribute to the development of diabetic nephropathy. Manganese superoxide dismutase (MnSOD) protects the cells from oxidative damage by scavenging free radicals. The demand for antioxidants is increased by smoking, which could disturb the balance between antioxidants and radicals. The present study aimed to determine whether a valine/alanine polymorphism in MnSOD (V16A, rs4880), alone or in combination with smoking, can contribute to development of diabetic nephropathy in 1,510 Finnish and Swedish patients with type 1 diabetes. Overt diabetic nephropathy (n = 619) was defined as having an albumin excretion rate (AER) >200 microg/min or renal replacement therapy; incipient diabetic nephropathy was defined as having an AER of 20-200 microg/min (n = 336). The control subjects had diabetes duration of >or=20 years, without albuminuria (AER <20 microg/min) and without antihypertensive treatment (n = 555). In addition to male sex and elevated A1C, smoking was significantly associated with diabetic nephropathy (overt plus incipient), odds ratio (OR) 2.00 (95% CI 1.60-2.50). When controlling for age at onset, diabetes duration, A1C, smoking, and sex, the Val/Val genotype was associated with an increase in risk of diabetic nephropathy (1.32 [1.00-1.74], P = 0.049). When evaluating the combined effect of genotype and smoking, we used logistic regression with stratification according to smoking status and genotype. The high-risk group (ever smoking plus Val/Val genotype) had 2.52 times increased risk of diabetic nephropathy (95% CI 1.73-3.69) compared with the low-risk group, but no departure from additivity was found. Our results indicate that smoking and homozygosity for the MnSOD Val allele is associated with an increased risk of diabetic nephropathy, which supports the hypothesis that oxidative stress contributes to the development of diabetic nephropathy.

A genome-wide linkage scan for genes controlling variation in renal function estimated by serum cystatin C levels in extended families with type 2 diabetes

We performed a variance components linkage analysis of renal function, measured as glomerular filtration rate (GFR), in 63 extended families with multiple members with type 2 diabetes. GFR was estimated from serum concentrations of cystatin C and creatinine in 406 diabetic and 428 nondiabetic relatives. Results for cystatin C were summarized because they are superior to creatinine results. GFR aggregates in families with significant heritability (h(2)) in diabetic (h(2) = 0.45, P < 1 x 10(-5)) and nondiabetic (h(2) = 0.36, P < 1 x 10(-3)) relatives. Genetic correlation (r(G) = 0.35) between the GFR of diabetic and nondiabetic relatives was less than one (P = 0.01), suggesting that genes controlling GFR variation in these groups are different. Linkage results supported this interpretation. In diabetic relatives, linkage was strong on chromosome 2q (logarithm of odds [LOD] = 4.1) and suggestive on 10q (LOD = 3.1) and 18p (LOD = 2.2). In nondiabetic relatives, linkage was suggestive on 3q (LOD = 2.2) and 11p (LOD = 2.1). When diabetic and nondiabetic relatives were combined, strong evidence for linkage was found only on 7p (LOD = 4.0). In conclusion, partially distinct sets of genes control GFR variation in relatives with and without diabetes on chromosome 2q, possibly on 10q and 18p in the former, and on 7p in both. None of these genes overlaps with genes controlling variation in urinary albumin excretion.

The AT2 gene may have a gender-specific effect on kidney function and pulse pressure in type I diabetic patients

Diabetic nephropathy shows a higher incidence in male subjects, which may in part be owing to genetic factors. The angiotensin II type 2 receptor (AT2), present in the renal glomerulus, may oppose the deleterious effects of the type I receptor (AT1) through vasodilatation and growth inhibition. We determined whether the functional intronic G1675A or A1818T polymorphism of the X-chromosomal AT2 gene is associated with blood pressure levels or with kidney function. We genotyped 996 (538 female/458 male subjects) Finnish patients with type I diabetes from the FinnDiane-study in a cross-sectional study. DNA samples were amplified using standard polymerase chain reaction protocol and the genotypes were determined by the minisequencing method. Male patients with the AA haplotype had a lower glomerular filtration rate (83 +/- 32 vs 94 +/- 34 ml min(-1) 1.73 m(-2), P = 0.008) and a higher pulse pressure (PP) (62 +/- 18 vs 57 +/- 15 mm Hg, P = 0.002; P < 0.05 after adjustment for age) than did those with the GT haplotype. No differences between the genotypes or haplotypes and these variables were evident in females. In males, the G1675A was also an independent variable in a linear regression analysis with PP (r(2) = 0.16, coefficient=3.64, s.e.m.=1.38, P < 0.01) as the dependent variable. These data suggest a gender-specific association between the AT2 gene and kidney function and premature aging of the arterial tree in patients with type I diabetes.

VEGF gene variability and type 1 diabetes: evidence for a protective role

Vascular endothelial growth factor (VEGF) is a multifunctional cytokine originally described as an angiogenic factor. A number of reports have recently demonstrated that VEGF increases pancreatic islet survival after islet transplantation by stimulating angiogenesis and improving islet revascularization. Whether VEGF can protect from the autoimmune destruction of insulin-producing beta-cells that characterizes the development of type 1 diabetes is presently unknown. To clarify this issue, we studied the association of three polymorphisms of the promoter region of VEGF with type 1 diabetes in the Italian and the Finnish populations. The polymorphisms considered [C(-2578)A, G(-1190)A, and G(-1154)A] are known to modulate in vitro and in vivo VEGF expression. We found that VEGF promoter genotypes are associated with type 1 diabetes in both populations, but with different combinations. In Italian individuals, the -2578AA and -1190AA genotypes are associated with type 1 diabetes and accelerate its onset, while in Finnish individuals, -1154GG and -1190GG protect from type 1 diabetes and delay its onset. In conclusion, because the expected functional consequence of both genotype combinations is a reduced VEGF expression in diabetic patients, we propose a protective role of VEGF in the development of type 1 diabetes.

Glu298Asp and NOS4ab polymorphisms in diabetic nephropathy

BACKGROUND AND AIMS

The risk of diabetic nephropathy (DN) increases with increase in intraglomerular pressure, which may partly be regulated by nitric oxide (NO). NO-production can be affected by polymorphisms in the endothelial NO-synthase gene (NOS3), hyperglycaemia and smoking. We therefore studied association between DN and two polymorphisms in NOS3, Glu298Asp and NOS4ab, in Caucasian type 1 diabetes (T1D) patients.

PATIENTS AND METHODS

A total of 1510 Finnish and Swedish T1D patients were included in a cross-sectional case-control study. Incipient DN was defined as an albumin excretion rate (AER) of 20-200 microg/min (n = 336). Overt DN = AER>200 microg/min or renal replacement therapy (n = 619). All patients with DN were considered as cases. The controls were T1D patients with diabetes duration 20 years, AER<20 microg/min and without antihypertensive treatment (n = 555). The genetic markers studied were a 27 bp repeat (NOS4ab) and Glu298Asp (rs1799983).

RESULTS

Age at onset of diabetes, male sex, duration of diabetes, HbA1c, blood pressure and smoking were assessed as possible confounders in the logistic regression analysis, which showed that homozygosity for the Glu-allele of the Glu298Asp-polymorphism was independently associated with increased risk of DN (OR = 1.46; 95% CI = 1.12-1.91). The variables smoking (OR = 2.13; 95% CI = 1.63-2.78), male sex (OR = 1.61; 95% CI = 1.23-2.10), HbA1c (OR per % increase above upper limit of the normal reference range = 1.02; 95% CI = 1.02-1.03), systolic (OR = 1.05; 95% CI = 1.04-1.06) and diastolic blood pressure (OR = 1.04; 95% CI = 1.02-1.05) also significantly and independently increased the risk of DN when taking age at diabetes onset and diabetes duration into account. The NOS4 a-allele was not associated with DN.

CONCLUSIONS

The Glu/Glu-genotype of the NOS3 Glu298Asp polymorphism may increase the risk of developing DN independently of other known risk factors.

The T1128C polymorphism of neuropeptide Y gene in a chinese population

BACKGROUND

Several papers have shown that the T1128C polymorphism of the neuropeptide Y (NPY) gene was related to certain diseases and disorders. However, the allele frequency of the 1128C showed significant differences among some populations with different genetic backgrounds, being absent in Japanese and Korean populations. Therefore, this present study was aimed to explore whether the T1128C polymorphism of the NPY gene exists in a Chinese population.

METHODS

A total of 304 newly diagnosed inpatients with coronary heart disease (CHD) were selected as the subjects in the present study. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis was performed to detect the T1128C polymorphism.

RESULTS

Of the 304 CHD patients, only one patient showed the T1128/C1128 genotype in the NPY gene, the others were all the T1128/T1128 genotype.

CONCLUSIONS

The T1128C polymorphism of the NPY gene is population specific and extremely low in a Chinese population.

The Leu7Pro polymorphism of preproNPY is associated with decreased insulin secretion, delayed ghrelin suppression, and increased cardiovascular responsiveness to norepinephrine during oral glucose tolerance test

CONTEXT

Neuropeptide Y (NPY) plays a role in angiogenesis, cardiovascular regulation, and hormone secretion. The leucine7 to proline7 (Leu7Pro) polymorphism of preproNPY is associated with vascular diseases and has an impact on hormone levels in healthy subjects.

OBJECTIVE

The current study investigated the role of the Leu7Pro polymorphism in metabolic and cardiovascular autonomic regulation.

DESIGN AND SUBJECTS

A 5-h oral glucose tolerance test was performed on 27 healthy volunteers representing two preproNPY genotypes (Leu7/Pro7 and Leu7/Leu7) matched for age, sex, body mass index and physical activity.

MAIN OUTCOME MEASURES

Simultaneously we performed cardiovascular autonomic function tests and plasma measurements of sympathetic transmitters, glucose, insulin, and ghrelin.

RESULTS

The subjects with Leu7/Pro7 genotype had decreased plasma NPY, norepinephrine (NE), and insulin concentrations and insulin to glucose ratios. The suppression of ghrelin concentrations after glucose ingestion was delayed in these subjects. They also had increased heart rate variability indices and baroreflex sensitivity. However, they displayed significant negative association of NE concentration with variability of low-frequency R-R-intervals and with baroreflex sensitivity.

CONCLUSIONS

The Leu7Pro polymorphism of preproNPY is related to decreased level of basal sympathetic activity, decreased insulin secretion, and delayed ghrelin suppression during oral glucose tolerance test. The increased responsiveness of autonomic functions to NE associated with the polymorphism may be connected to increased cardiovascular vulnerability.