Association between Gly241Arg ICAM-1 gene polymorphism and serum sICAM-1 concentration in the Stanislas cohort

Evaluating Associations between Average Pain Intensity and Genetic Variation in People with Sickle Cell Disease: An Exploratory Study

BACKGROUND

Pain is one of the most common and deleterious symptoms experienced by individuals with sickle cell disease (SCD). There is a paucity of studies identifying potential genetic mechanisms of pain in this population.

AIM

Examine associations between 11 functional single nucleotide polymorphisms in 9 candidate genes with reports of average pain intensity in individuals with sickle cell disease.

METHOD

Cross-sectional analyses were performed on data and blood samples collected through the Duke SCD Implementation Consortium Registry. Participants were asked to rate their pain "on the average" using an 11-point numeric rating scale (0 = no pain; 10 = pain as bad as you can imagine). We genotyped 11 single nucleotide polymorphisms in 9 pain-related genes using TaqMan® Genotyping Assays. Associations between each polymorphism and reports of average pain were evaluated.

RESULTS

The 86 participants (mean age: 28.7 years; 64% female) included in this study reported moderate pain on average (Mean = 4, Standard Deviation = 2.4). ICAM1 rs1799969 was the only genetic polymorphism that was significantly associated with pain (p = .01). Individuals with one or more minor alleles had lower average pain (Mean = 1.25, Standard Deviation = 1.50) than individuals without a minor allele (Mean = 4.13, Standard Deviation = 2.25). The effect size for ICAM1 rs1799969 was 1.30, which is considered large. The effect sizes for all other single nucleotide polymorphisms ranged from small to medium (range: 0-0.3).

CONCLUSIONS

Our findings provide preliminary evidence that the minor allele in ICAM1 rs1799969 had protective effects against experiencing more severe pain in sickle cell disease.

Boswellia serrata Preserves Intestinal Epithelial Barrier from Oxidative and Inflammatory Damage

Aminosalicylates, corticosteroids and immunosuppressants are currently the therapeutic choices in inflammatory bowel diseases (IBD), however, with limited remission and often serious side effects. Meanwhile complementary and alternative medicine (CAM) use is increasing, particularly herbal medicine. Boswellia serrata is a traditional Ayurvedic remedy with anti-inflammatory properties, of interest for its usefulness in IBDs. The mechanism of this pharmacological potential of Boswellia serrata was investigated in colonic epithelial cell monolayers exposed to H2O2 or INF-γ+TNF-α, chosen as in vitro experimental model of intestinal inflammation. The barrier function was evaluated by the transepithelial electrical resistance (TEER) and paracellular permeability assay, and by the tight junction proteins (zonula occludens-1, ZO-1 and occludin) immunofluorescence. The expression of phosphorylated NF-κB and reactive oxygen species (ROS) generation were determined by immunoblot and cytofluorimetric assay, respectively. Boswellia serrata oleo-gum extract (BSE) and its pure derivative acetyl-11-keto-β-boswellic acid (AKBA), were tested at 0.1-10 μg/ml and 0.027 μg/ml, respectively. BSE and AKBA safety was demonstrated by no alteration of intestinal cell viability and barrier function and integrity biomarkers. H2O2 or INF-γ+TNF-α treatment of Caco-2 cell monolayers significantly reduced TEER, increased paracellular permeability and caused the disassembly of tight junction proteins occludin and ZO-1. BSE and AKBA pretreatment significantly prevented functional and morphological alterations and also the NF-κB phosphorylation induced by the inflammatory stimuli. At the same concentrations BSE and AKBA counteracted the increase of ROS caused by H2O2 exposure. Data showed the positive correlation of the antioxidant activity with the mechanism involved in the physiologic maintenance of the integrity and function of the intestinal epithelium. This study elucidates the pharmacological mechanisms mediated by BSE, in protecting intestinal epithelial barrier from inflammatory damage and supports its use as safe adjuvant in patients affected by IBD.

Association of intercellular adhesion molecular-1 gene polymorphism in ischemic stroke patients

BACKGROUND

Ischemic stroke (IS) is a prevalent disease causing a body disability, the third leading cause of death in Taiwan. It shows that the level of intercellular adhesion molecular-1 (ICAM-1) in IS patients is higher than control subjects.

OBJECTIVE

This study is to investigate the possible association of ICAM-1 (G1548A) polymorphism in IS patients.

MATERIALS AND METHODS

A total of 646 subjects were enrolled in this study, including 312 IS patients, and 334 controls without a history of symptomatic IS. The ICAM-1 (G1548A) polymorphism was analyzed by polymerase chain reaction and restriction fragment length polymorphism. Clinical factors were also determined.

RESULTS

The frequencies of the ICAM-1 (G1548A) polymorphism for G/G, G/A, and A/A were 74.8%, 23.9%, and 0.3%, respectively, in healthy controls, and 62.8%, 32.1%, and 5.1%, respectively, in patients. The frequency of the ICAM-1 (G1548A) A allele (21.2% versus 13.2%, respectively; P = 0.007) and the carriers of the ICAM-1 (G1548A) A allele (37.2% versus 25.2%; P = 0.019, OR 1.76, 95% CI 1.1-2.83) are great in IS patients compared with healthy controls. There is a higher risk of IS associated with homozygosity for the ICAM-1 (G1548A) A allele (AA genotype) compared with the control population (5.1% vs. 0.3%, respectively, P = 0.04; OR 5.1, 95% CI 1.19-21.66). We also observed both hypertension and diabetes has shown a positive association with IS.

CONCLUSIONS

The ICAM-1 (G1548A) polymorphism was associated with independent risk factor for the development of IS.

Genetic polymorphisms of ICAM 1 and IL28 as predictors of liver fibrosis severity and viral clearance in hepatitis C genotype 4

BACKGROUND AND OBJECTIVES

Intercellular adhesion molecule-1 (ICAM-1) is located on chromosome 19p13.2, and this protein plays an important role in the pathogenesis of the hepatitis C virus (HCV). The rs12979860 polymorphism of the IL-28B gene participates in HCV clearance. This study investigated the association of the genetic markers (SNPs), rs5496, rs281437 and rs12979860 polymorphisms, with viral clearance and the progression of hepatic fibrosis in HCV genotype 4 patients who were treated with pegylated interferon and ribavirin.

METHODS

Thirty consecutive HCV genotype 4 patients who were treated with pegylated interferon and ribavirin therapy for 48 weeks were grouped into responders (control group) and non-responders (case group). The severity of fibrosis was classified according to the Scheuer Score. SNP genotyping of rs5496 [A/G], rs281437 [C/T] and rs12979860 [C/T] were performed using the 5' nuclease assay with a TaqMan MGB probe in an ABI 7500 Fast Real-Time PCR System (Applied Biosystems).

RESULTS

All SNPs exhibited Hardy-Weinberg Equilibrium (HWE). The patients with the C allele of rs12979860 exhibited an approximately eight times higher risk of SVR compared to patients with the T allele (aOR=7.98; CI: 1.07-59.36, P=0.012). No significant association of rs5496 and rs281437 with treatment response was detected (P=0.185 and P=0.123, respectively). Patients with the T allele of rs281437 exhibited an approximately 13 times higher risk of severe fibrosis compared to patients with the C allele (aOR=13.0; CI: 1.32-128.11, P= 0.028). No significant association of the other genetic variants with the degree of fibrosis in the study subjects was detected for rs5496 and rs12979860.

CONCLUSION

The present study revealed associations between the ICAM-1 gene marker, rs281437, and the progression of hepatic fibrosis in HCV genotype 4 and rs12979860 of the IL-28 B gene with viral clearance.

Lack of association between intercellular adhesion molecule-1 (ICAM-1) polymorphisms and polycystic ovary syndrome

PURPOSE

This study examined the possible association of G241R and K469E single nucleotide polymorphisms (SNPs) of ICAM-1 gene with the occurrence and clinical/biochemical characteristics of polycystic ovary syndrome (PCOS).

METHODS

G241R and K469E SNPs in DNA from peripheral blood leukocytes of 169 PCOS and 259 healthy control women were investigated by real-time PCR combined with melting curve analysis using fluorescence-labeled hybridization probes.

RESULTS

We did not find significant differences in the distributions of G241R and K469E polymorphisms, nor in the haplotype frequencies between PCOS and control women. None of the studied polymorphisms were found to affect insulin resistance indices significantly.

CONCLUSIONS

These preliminary results suggest that the 241 and 469 SNPs of ICAM-1 gene may not be risk factors for PCOS. Further studies with a larger cohort, analyzing other ICAM-1 polymorphisms are necessary to support our observations before any statement can be made about the relationship between PCOS and ICAM-1 polymorphisms.

Genome-wide association analysis of soluble ICAM-1 concentration reveals novel associations at the NFKBIK, PNPLA3, RELA, and SH2B3 loci

Soluble ICAM-1 (sICAM-1) is an endothelium-derived inflammatory marker that has been associated with diverse conditions such as myocardial infarction, diabetes, stroke, and malaria. Despite evidence for a heritable component to sICAM-1 levels, few genetic loci have been identified so far. To comprehensively address this issue, we performed a genome-wide association analysis of sICAM-1 concentration in 22,435 apparently healthy women from the Women's Genome Health Study. While our results confirm the previously reported associations at the ABO and ICAM1 loci, four novel associations were identified in the vicinity of NFKBIK (rs3136642, P = 5.4 × 10(-9)), PNPLA3 (rs738409, P  =  5.8 × 10(-9)), RELA (rs1049728, P =  2.7 × 10(-16)), and SH2B3 (rs3184504, P =  2.9 × 10(-17)). Two loci, NFKBIB and RELA, are involved in NFKB signaling pathway; PNPLA3 is known for its association with fatty liver disease; and SH3B2 has been associated with a multitude of traits and disease including myocardial infarction. These associations provide insights into the genetic regulation of sICAM-1 levels and implicate these loci in the regulation of endothelial function.

Genome-wide association analysis of soluble ICAM-1 concentration reveals novel associations at the NFKBIK, PNPLA3, RELA, and SH2B3 loci

Soluble ICAM-1 (sICAM-1) is an endothelium-derived inflammatory marker that has been associated with diverse conditions such as myocardial infarction, diabetes, stroke, and malaria. Despite evidence for a heritable component to sICAM-1 levels, few genetic loci have been identified so far. To comprehensively address this issue, we performed a genome-wide association analysis of sICAM-1 concentration in 22,435 apparently healthy women from the Women's Genome Health Study. While our results confirm the previously reported associations at the ABO and ICAM1 loci, four novel associations were identified in the vicinity of NFKBIK (rs3136642, P = 5.4×10⁻⁹), PNPLA3 (rs738409, P = 5.8×10⁻⁹), RELA (rs1049728, P = 2.7×10⁻¹⁶), and SH2B3 (rs3184504, P = 2.9×10⁻¹⁷). Two loci, NFKBIB and RELA, are involved in NFKB signaling pathway; PNPLA3 is known for its association with fatty liver disease; and SH3B2 has been associated with a multitude of traits and disease including myocardial infarction. These associations provide insights into the genetic regulation of sICAM-1 levels and implicate these loci in the regulation of endothelial function.

Soluble Intercellular Adhesion Molecule 1 (sICAM-1) is an inflammatory marker that has been associated with several common diseases such as diabetes, heart disease, stroke, and malaria. While it is known that blood concentrations of sICAM-1 are at least partially genetically determined, our current knowledge of which genes mediate this effect is limited. Taking advantage of technologies allowing us to interrogate genetic variation on a whole-genome basis, we found that variation in the NFKBIK, PNPLA3, RELA, and SH2B3 genes are important determinant of sICAM-1 blood concentrations. The NFKBIB and RELA genes are involved in regulation of inflammation. These observations are significant because this is the first report of genetic association within these extensively studied inflammation genes. The PNPLA3 gene has previously been associated with liver disease, and the SH2B3 gene has been associated with a multitude of traits including cardiovascular disease. Extension of these associations to sICAM-1 adds to the intriguing diversity of effects of these genes.

On the use of variance per genotype as a tool to identify quantitative trait interaction effects: a report from the Women's Genome Health Study

Testing for genetic effects on mean values of a quantitative trait has been a very successful strategy. However, most studies to date have not explored genetic effects on the variance of quantitative traits as a relevant consequence of genetic variation. In this report, we demonstrate that, under plausible scenarios of genetic interaction, the variance of a quantitative trait is expected to differ among the three possible genotypes of a biallelic SNP. Leveraging this observation with Levene's test of equality of variance, we propose a novel method to prioritize SNPs for subsequent gene–gene and gene–environment testing. This method has the advantageous characteristic that the interacting covariate need not be known or measured for a SNP to be prioritized. Using simulations, we show that this method has increased power over exhaustive search under certain conditions. We further investigate the utility of variance per genotype by examining data from the Women's Genome Health Study. Using this dataset, we identify new interactions between the LEPR SNP rs12753193 and body mass index in the prediction of C-reactive protein levels, between the ICAM1 SNP rs1799969 and smoking in the prediction of soluble ICAM-1 levels, and between the PNPLA3 SNP rs738409 and body mass index in the prediction of soluble ICAM-1 levels. These results demonstrate the utility of our approach and provide novel genetic insight into the relationship among obesity, smoking, and inflammation.

Finding gene–gene and gene–environment interactions is a major challenge in genetics. In this report, we propose a novel method to help detect these interactions. This method works by first identifying a subset of genetic variants more likely to be involved in genetic interactions and then testing these variants for interaction effects. Using this method, we were able to identify three previously unknown genetic interactions. The first interaction involves a measure of body fat and a genetic variant of the LEPR gene in the prediction of C-reactive protein concentration, a marker of inflammation. The second interaction involves the same measure of body fat and a genetic variant of the PNPLA3 gene in the prediction of ICAM-1 levels, also a marker of inflammation. These results are significant because both LEPR and PNPLA3 are linked to the biological response to increased body fat, and inflammation itself is known to be increased in obesity and is thought to contribute to its adverse health effect. Finally, a third interaction was identified between a genetic variant of the ICAM1 gene and smoking in the prediction of ICAM-1 levels. The ICAM1 gene encodes ICAM-1 itself and smoking is known to be an important determinant of ICAM-1 concentrations.

Large-scale genomic studies reveal central role of ABO in sP-selectin and sICAM-1 levels

P-selectin and intercellular adhesion molecule-1 (ICAM-1) participate in inflammatory processes by promoting adhesion of leukocytes to vascular wall endothelium. Their soluble levels have been associated with adverse cardiovascular events. To identify loci affecting soluble levels of P-selectin (sP-selectin) and ICAM-1 (sICAM-1), we performed a genome-wide association study in a sample of 4115 (sP-selectin) and 9813 (sICAM-1) individuals of European ancestry as a part of The Cohorts for Heart and Aging Research in Genome Epidemiology consortium. The most significant SNP association for sP-selectin was within the SELP gene (rs6136, P = 4.05 x 10(-61)) and for sICAM-1 levels within the ICAM-1 gene (rs3093030, P = 3.53 x 10(-23)). Both sP-selectin and sICAM-1 were associated with ABO gene variants (rs579459, P = 1.86 x 10(-41) and rs649129, P = 1.22 x 10(-15), respectively) and in both cases the observed associations could be accounted for by the A1 allele of the ABO blood group. The absence of an association between ABO blood group and platelet-bound P-selectin levels in an independent subsample (N = 1088) from the ARIC study, suggests that the ABO blood group may influence cleavage of the P-selectin protein from the cell surface or clearance from the circulation, rather than its production and cellular presentation. These results provide new insights into adhesion molecule biology.

LS-SNP/PDB: annotated non-synonymous SNPs mapped to Protein Data Bank structures

SUMMARY

LS-SNP/PDB is a new WWW resource for genome-wide annotation of human non-synonymous (amino acid changing) SNPs. It serves high-quality protein graphics rendered with UCSF Chimera molecular visualization software. The system is kept up-to-date by an automated, high-throughput build pipeline that systematically maps human nsSNPs onto Protein Data Bank structures and annotates several biologically relevant features.

AVAILABILITY

LS-SNP/PDB is available at (http://ls-snp.icm.jhu.edu/ls-snp-pdb) and via links from protein data bank (PDB) biology and chemistry tabs, UCSC Genome Browser Gene Details and SNP Details pages and PharmGKB Gene Variants Downloads/Cross-References pages.

The relation of genetic and environmental factors to systemic inflammatory biomarker concentrations

BACKGROUND

Environmental and genetic correlates of inflammatory marker variability are incompletely understood. In the family-based Framingham Heart Study, we investigated heritability and candidate gene associations of systemic inflammatory biomarkers.

METHODS AND RESULTS

In offspring participants (n=3710), we examined 11 inflammatory biomarkers (CD40 ligand, C-reactive protein, intercellular adhesion molecule-1, interleukin-6, urinary isoprostanes, monocyte chemoattractant protein-1, myeloperoxidase, P-selectin, tumor necrosis factor-alpha, tumor necrosis factor receptor II, fibrinogen). Heritability and bivariate genetic and environmental correlations were assessed by Sequential Oligogenic Linkage Analysis routines in 1012 family members. We examined 1943 tagging single-nucleotide polymorphisms in 233 inflammatory pathway genes with >or=5 minor allele carriers using a general genetic linear model. Clinical correlates explained 2.4% (CD40 ligand) to 28.5% (C-reactive protein) of the variability in inflammatory biomarkers. Estimated heritability ranged from 10.9% (isoprostanes) to 44.8% (P-selectin). Most correlations between biomarkers were weak although statistically significant. A total of 45 single-nucleotide polymorphism-biomarker associations met the q-value threshold of 0.25. Novel top single-nucleotide polymorphisms were observed in ICAM1 gene in relation to intercellular adhesion molecule-1 concentrations (rs1799969, P=1.32 x 10(-8)) and MPO in relation to myeloperoxidase (rs28730837, P=1.9 x 10(-5)). Lowest P values for trans-acting single-nucleotide polymorphisms were observed for APCS with monocyte chemoattractant protein-1 concentrations (rs1374486, P=1.01 x 10(-7)) and confirmed for IL6R with interleukin-6 concentrations (rs8192284, P=3.36 x 10(-5)). Novel potential candidates (APCS, MPO) need to be replicated.

CONCLUSIONS

Our community-based data support the relevance of clinical and genetic factors for explaining variation in inflammatory biomarker traits.

Intercellular adhesion molecule-1 K469E polymorphism in Korean patients with spontaneous preterm delivery

OBJECTIVES

To investigate the association between intercellular adhesion molecule-1 (ICAM-1) gene K469E polymorphism and spontaneous preterm delivery in a Korean population.

METHODS

Genomic DNA was extracted from whole blood from 55 women experiencing preterm labor and 153 multiparous women (control group) with a history of at least 2 term deliveries. DNA samples were analyzed by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

The spontaneous preterm delivery (SPD) group carried the 469E allele significantly more frequently than those in the control group (odds ratio [OR], 1.62; 95% CI, 1.04-2.53). The EE genotype was significantly associated with increased risk of SPD (OR, 2.84; 95% CI, 1.17-6.89; P = 0.02). Allelic frequencies in women with abnormal C-reactive protein levels (K = 0.48; E = 0.52) were significantly different from frequencies in the controls (K = 0.68; E = 0.32) (P = 0.006).

CONCLUSIONS

ICAM-1 gene K469E polymorphism may be a candidate region and useful predictor of susceptibility to SPD in the Korean population.

The STANISLAS Cohort: a 10-year follow-up of supposed healthy families. Gene-environment interactions, reference values and evaluation of biomarkers in prevention of cardiovascular diseases

The description of this familial longitudinal cohort was published in this journal 10 years ago, in 1998. To date, 117 publications on the STANISLAS Cohort (SC) have appeared, corresponding to five main categories of results: familial resemblance and heritability; genetics and gene-environment interactions; mRNA and proteins as gene products; reference values and biological variations of proteins; and finally preventive medicine and prepathological epidemiological data. More than 600 data values on demographic and laboratory data have been collected on each individual taking part out of the 1006 families at the beginning and for all three recruitments. Serum and plasma are stored in liquid nitrogen for all participants for all three recruitments. DNA has been extracted from all participants and mRNA from 357 families. They are stored at -80 degrees C. Owing to the SC study, heritability and many gene-environment interactions have been described. The expression of 166 genes related to cardiovascular diseases was measured in peripheral blood mononuclear cells RNA. Reference values for proteins and vitamins have been established in addition to reference values for the carotid and femoral intima media thickness in adults and children. The data obtained contribute to a better understanding of the relation between the studied polymorphisms (161 polymorphic sites) and health, and predisposition to obesity, high blood pressure and metabolic syndrome. To the best of our knowledge, the SC study is internationally the only longitudinal family cohort of subjects who are presumed to be healthy, which enables the study of the chain DNA-RNA-proteins.

Novel association of ABO histo-blood group antigen with soluble ICAM-1: results of a genome-wide association study of 6,578 women

While circulating levels of soluble Intercellular Adhesion Molecule 1 (sICAM-1) have been associated with diverse conditions including myocardial infarction, stroke, malaria, and diabetes, comprehensive analysis of the common genetic determinants of sICAM-1 is not available. In a genome-wide association study conducted among 6,578 participants in the Women's Genome Health Study, we find that three SNPs at the ICAM1 (19p13.2) locus (rs1799969, rs5498 and rs281437) are non-redundantly associated with plasma sICAM-1 concentrations at a genome-wide significance level (P<5×10⁻⁸), thus extending prior results from linkage and candidate gene studies. We also find that a single SNP (rs507666, P = 5.1×10⁻²⁹) at the ABO (9q34.2) locus is highly correlated with sICAM-1 concentrations. The novel association at the ABO locus provides evidence for a previously unknown regulatory role of histo-blood group antigens in inflammatory adhesion processes.

Soluble Intercellular Adhesion Molecule 1 (sICAM-1) is an inflammatory marker that has been associated with several common diseases such as diabetes, heart disease, stroke, and malaria. While it is known that blood concentrations of sICAM-1 are at least partially genetically determined, our current knowledge of which genes mediate this effect is limited. Taking advantage of new technologies allowing us to interrogate genetic variation on a whole genome basis, we found that a variation in the ABO gene is an important determinant of sICAM-1 blood concentrations. Since the ABO gene is responsible for the ABO blood groups, this discovery sheds light on a new role for blood groups and offers novel mechanisms to explain the association between sICAM-1 blood concentrations and various common diseases.

Intercellular adhesion molecule 1 (ICAM1) Lys56Met and Gly241Arg gene variants, plasma-soluble ICAM1 concentrations, and risk of incident cardiovascular events in 23,014 initially healthy white women

BACKGROUND AND PURPOSE

The objective of this study was to examine the association of 2 nonsynonymous intercellular adhesion molecule 1 (ICAM1) gene variants (Lys56Met and Gly241Arg) with baseline plasma soluble ICAM1 concentrations and with risk of total and selected cardiovascular disease (CVD) events in a prospective cohort of 23 014 apparently healthy white American women followed for 10 years. ICAM1 variations have been associated with plasma soluble ICAM1 concentrations and inflammatory conditions, including atherosclerosis. However, to date, no large prospective, genetic-epidemiological data set is available that would allow evaluation of the degree of association of these gene variants with risk of CVD.

METHODS

ICAM1 genotypes and baseline plasma soluble ICAM1 concentrations were determined. The primary outcome measure was a composite CVD end point (incident ischemic stroke, myocardial infarction, or death due to ischemic CVD); other measures were incident ischemic stroke, myocardial infarction, and coronary revascularization. During follow-up, 751 total incident CVD events, 187 incident myocardial infarction cases, 203 incident ischemic stroke cases, and 433 coronary revascularization events occurred.

RESULTS

All observed genotype frequencies were in Hardy-Weinberg equilibrium across the whole sample population. We found baseline plasma soluble ICAM1 concentrations to be significantly reduced among carriers of Met56 allele (P<0.0001) and Arg241 allele (P<0.0001) as compared with the respective noncarriers of these variants. However, the polymorphisms tested and the respective haplotypes were neither associated with overall risk nor with risk with risk for selected CVD events regardless of whether analyses were adjusted for traditional CVD risk factors/confounders (all P values >0.10).

CONCLUSIONS

In this large prospective study, we found an association of the nonsynonymous gene variants tested with reduced baseline plasma soluble ICAM1 concentrations. However, no evidence was found for an association of the gene variants tested with the overall or selected CVD end points examined, suggesting that these variants may not add useful aids to current risk predictors for early assessment of cardiovascular events.

Genome-wide association with select biomarker traits in the Framingham Heart Study

BACKGROUND

Systemic biomarkers provide insights into disease pathogenesis, diagnosis, and risk stratification. Many systemic biomarker concentrations are heritable phenotypes. Genome-wide association studies (GWAS) provide mechanisms to investigate the genetic contributions to biomarker variability unconstrained by current knowledge of physiological relations.

METHODS

We examined the association of Affymetrix 100K GeneChip single nucleotide polymorphisms (SNPs) to 22 systemic biomarker concentrations in 4 biological domains: inflammation/oxidative stress; natriuretic peptides; liver function; and vitamins. Related members of the Framingham Offspring cohort (n = 1012; mean age 59 +/- 10 years, 51% women) had both phenotype and genotype data (minimum-maximum per phenotype n = 507-1008). We used Generalized Estimating Equations (GEE), Family Based Association Tests (FBAT) and variance components linkage to relate SNPs to multivariable-adjusted biomarker residuals. Autosomal SNPs (n = 70,987) meeting the following criteria were studied: minor allele frequency > or = 10%, call rate > or = 80% and Hardy-Weinberg equilibrium p > or = 0.001.

RESULTS

With GEE, 58 SNPs had p < 10(-6): the top SNPs were rs2494250 (p = 1.00*10(-14)) and rs4128725 (p = 3.68*10(-12)) for monocyte chemoattractant protein-1 (MCP1), and rs2794520 (p = 2.83*10(-8)) and rs2808629 (p = 3.19*10(-8)) for C-reactive protein (CRP) averaged from 3 examinations (over about 20 years). With FBAT, 11 SNPs had p < 10(-6): the top SNPs were the same for MCP1 (rs4128725, p = 3.28*10(-8), and rs2494250, p = 3.55*10(-8)), and also included B-type natriuretic peptide (rs437021, p = 1.01*10(-6)) and Vitamin K percent undercarboxylated osteocalcin (rs2052028, p = 1.07*10(-6)). The peak LOD (logarithm of the odds) scores were for MCP1 (4.38, chromosome 1) and CRP (3.28, chromosome 1; previously described) concentrations; of note the 1.5 support interval included the MCP1 and CRP SNPs reported above (GEE model). Previous candidate SNP associations with circulating CRP concentrations were replicated at p < 0.05; the SNPs rs2794520 and rs2808629 are in linkage disequilibrium with previously reported SNPs. GEE, FBAT and linkage results are posted at http://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/study.cgi?id=phs000007 webcite.

CONCLUSION

The Framingham GWAS represents a resource to describe potentially novel genetic influences on systemic biomarker variability. The newly described associations will need to be replicated in other studies.

Association of intercellular adhesion molecule 1 polymorphisms with retinopathy in Chinese patients with Type 2 diabetes

AIMS

To investigate the relationship of the K469E and G241R polymorphisms of the intercellular adhesion molecule 1 (ICAM-1) gene with diabetic retinopathy in Chinese patients with Type 2 diabetes mellitus.

PATIENTS AND METHODS

One hundred and seventy-two Chinese patients with Type 2 diabetes and 80 normal control subjects were recruited. Patients with diabetes were placed into two groups: the diabetic retinopathy (DR) group and the non-diabetic retinopathy (NDR) group. The DR group was subdivided into those with proliferative retinopathy (PDR) and non-proliferative retinopathy (NPDR). Genomic DNA was prepared using the hydroxybenzene-chloroform extraction method. Genotypes and alleles were detected by polymerase chain reaction-heteroduplex-single-strand conformation polymorphism (PCR-HA-SSCP) analysis combined with gene sequencing.

RESULTS

The patients with retinopathy had an increased frequency of the K469K genotype compared with both the patients without retinopathy and the control subjects (61.4 vs. 40.0 and 35.0%, respectively; chi(2) = 8.280 and 13.952, respectively; P < 0.05). The frequency of the K allele in the DR group was higher than in the NDR group and control subjects (75.4 vs. 58.8 and 61.3%, respectively; chi(2) = 9.693 and 11.219, respectively; P < 0.05). Genotype and allele frequencies were similar in the NDR group and control subjects, and in the PDR and NPDR groups.

CONCLUSION

The ICAM-1 gene K469E polymorphism is associated with diabetic retinopathy in Chinese patients with Type 2 diabetes. Patients with the K469K genotype were more likely to have diabetic retinopathy than patients with the K469E or E469E genotype.

ICAM1 amino-acid variant K469E is associated with paediatric bronchial asthma and elevated sICAM1 levels

Intercellular adhesion molecule-1 (ICAM1) acts as ligand for beta2-integrin molecules and mediates leucocyte trafficking to the site of inflammation. Intercellular adhesion molecule-1-deficient mice show impaired lymphocyte recruitment to the lung, less airway hyper-responsiveness and less lung inflammation than healthy controls. Thus, the aim of the study was to test common ICAM1 polymorphisms for association with paediatric asthma. Furthermore, we were interested in whether soluble ICAM1 (sICAM1) serum levels were in correlation with genotypes. The following polymorphisms in ICAM1 were genotyped on 352 children with asthma and 270 controls: rs5491 (resulting in the amino-acid exchange K56M), rs5493 (G241S), rs5498 (K469E), rs5030400 (R478W) and rs885743 in the 3'-untranslated region. In addition, sICAM1 serum levels were measured. Only K469E and rs885743 were present in our populations. K469E showed association with asthma (P = 0.0037 with Armitage's trend test). Haplotype analysis by FAMHAP using both polymorphisms revealed association with asthma by P < 0.000001. In addition, serum sICAM1 levels were correlated with K469E genotypes (P = 0.009 by Kruskal-Wallis test). We conclude from our data that K469KE is associated with paediatric asthma in the German population. Furthermore, the same polymorphism is correlated with serum levels of sICAM1. Functional analyses have to further clarify the pathophysiological mechanism conferred by the polymorphisms.

Association between ICAM-1 Gly-Arg polymorphism and renal parenchymal scarring following childhood urinary tract infection

Renal parenchymal scarring (RPS) following urinary tract infection (UTI) is an important cause of renal morbidity in children. Studies have shown that the intensity of the inflammatory response following infection is related to the risk of RPS. However, genetic variability in this response has not been studied. Adhesion molecules play a crucial role in leucocyte recruitment following infection, and polymorphisms have been reported in the genes for key cell adhesion molecules. We have investigated the possibility that children who develop RPS following UTI may exhibit altered genotype or allele frequencies for polymorphisms of the intercellular adhesion molecule-1 (ICAM-1) (exons 4 and 6), E-selectin (exons 2 and 4), platelet endothelial cell adhesion molecule-1 (PECAM-1) (exon 3) and CD11b (3'UTR) genes, which may predict outcome of UTI. DNA was isolated from 99 children shown to have developed RPS, 43 children with no evidence of scarring (NS) following UTI and 170 healthy controls. Genotyping was performed by restriction fragment length polymorphism (RFLP) analysis. When the RPS group was compared with the NS group, there was a significant reduction in the frequency of the ICAM-1 exon 4 A allele (10.6 vs. 21.3%, respectively, chi2 = 6.01, P = 0.014). There was no significant difference in either allele or genotype frequency for any of the other polymorphisms studied. These data suggest that the A allele of the ICAM-1 exon 4 polymorphism may protect against the risk of RPS following UTI and may participate in the regulation of the inflammatory response following UTI.

Circulating markers of endothelial function in cardiovascular disease

Endothelial dysfunction is a key event in cardiovascular disease. Measurement of endothelial dysfunction in vivo presents a major challenge, but has important implications since it may identify the clinical need for therapeutic intervention, specifically in primary prevention. Several biological markers have been used as indicators of endothelial dysfunction. The soluble adhesion molecules sICAM-1 and sVCAM-1 lack specificity and are increased in inflammatory processes. Both markers are increased in coronary artery disease. sICAM-1 level predicts the risk for cardiovascular disease or diabetes mellitus in healthy individuals. sE-selectin is specific for the endothelium and is increased in coronary artery disease and diabetes mellitus. sE-selectin is also associated with diabetic risk. The endothelium-specific marker, soluble thrombomodulin, is associated with severity of coronary artery disease, stroke or peripheral occlusive arterial disease and is not increased in healthy or asymptomatic subjects. Interestingly, thrombomodulin decreases during treatment of hypercholesterolemia or hyperhomocysteinemia. In contrast, von Willebrand factor is the best endothelial biomarker and predicts risk for ischemic heart disease or stroke.

Selected gene polymorphisms and their interaction with maternal smoking, as risk factors for gastroschisis

BACKGROUND

Gastroschisis is a severe birth defect in which the infant is born with a portion of the intestines extruding through a small tear in the abdominal wall, usually to the right of the umbilical cord. Its etiology is unknown, but the prevailing hypothesis is that it results from a vascular accident at the time of involution of the right umbilical vein or of the development of the superior mesenteric artery.

METHODS

In a case-control study of 57 cases of gastroschisis and 506 controls, we tested DNA for polymorphisms of 32 genes representing enzymes involved in angiogenesis, blood vessel integrity, inflammation, wound repair, and dermal or epidermal strength.

RESULTS

In logistic regression, controlling for maternal ethnicity, and using the homozygote wild-type as referent, the following gene polymorphisms were associated with an increased risk for a gastroschisis for heterozygotes: ICAM1 gly241arg (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.1 -3.4); NOS3 glu298asp (OR, 1.9; 95% CI, 1.1-3.4); NPPA 2238T > C (OR, 1.9; 95% CI, 1.0-3.4); and ADD1 gly460trp (OR, 1.5; 95% CI, 0.8-2.8). Additionally, for the NPPA and ADD1 single-nucleotide polymorphisms (SNPs), the homozygote variants had a significantly higher risk than the heterozygotes (OR, 7.5; 95% CI, 1.7-33.5 and OR, 4.9; 95% CI, 1.9-12.9, respectively). Three SNPs showed a strong interaction with maternal smoking. The risk for smokers with 1 or 2 variant alleles compared to nonsmokers with the wild-type allele were: NOS3 (OR, 5.2; 95% CI, 2.4-11.4); ICAM1 (OR, 5.2; 95% CI, 2.1-12.7); and NPPA (OR, 6.4; 95% CI, 2.8-14.6).

CONCLUSIONS

These results support the hypothesis of a vascular compromise as part of a multifactorial etiology of gastroschisis involving both genes and environmental factors.

Intercellular adhesion molecule-1 and childhood asthma

We investigated the role of intercellular adhesion molecule-1 in childhood asthma by examining associations of functional variants at codons 29 (A --> T), 241 (G --> A), and 469 (A --> G) in Children's Health Study participants. Among African-Americans, 469G carriers had lower risk for asthma (ever asthma OR = 0.4, 95% CI 0.2-0.9) but increased risk among 29T carriers (early onset active asthma OR = 2.2, 95% CI 1.0-4.9). Protective associations with the 241A allele were observed among non-Hispanic and Hispanic whites (ever asthma OR = 0.7, 95% CI 0.6-0.9; early onset active asthma OR = 0.5, 95% CI 0.4-0.8), and these associations were not confounded by population stratification. To gauge the potential impact of confounding by population stratification, we performed analyses by ethnic group and in an independent family-based sample. Regional associations were stable across analyses. Haplotype associations of the four common haplotypes (29A/241G/469A, AGG, TGA, and AAG) with asthma showed that Hispanics with the AAG haplotype had lower asthma risk compared to carriers of two copies of AGA haplotype (OR = 0.6, 95% CI 0.4-0.9). Among non-Hispanic whites, the AAG haplotype was associated with reduced risk for active asthma. For African-Americans, who had a low frequency of the AAG haplotype, carrying one copy of the AGG haplotype was associated with a lower risk of asthma (OR = 0.3, 95% CI 0.1-0.8), as compared with two copies of the AGA haplotype. Consistent with information on variant function, the 241A and 469G variants may indicate haplotypes that are associated with reduced risk for asthma.

Quantitative genetic analysis of cellular adhesion molecules: the Fels Longitudinal Study

Circulating concentrations of inflammatory markers predict cardiovascular disease (CVD) risk and are closely associated with obesity. However, little is known concerning genetic influences on serum levels of inflammatory markers. In this study, we estimated the heritability (h2) of soluble cellular adhesion molecule (sCAM) concentrations and examined the correlational architecture between different sCAMs. The study population included 234 men and 270 women aged 18-76 years, belonging to 121 families participating in the Fels Longitudinal Study. Serum levels of soluble intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), E-selectin (sESEL-1) and P-selectin (sPSEL-1) were assayed using commercially available kits. A variance components-based maximum likelihood method was used to estimate the h2 of the different serum inflammatory markers while simultaneously adjusting for the effects of known CVD risk factors, such as age and smoking. Additionally, we used bivariate extensions of these methods to estimate genetic and random environmental correlations among sCAMs. Levels of sCAMs were significantly heritable: h2=0.24+/-0.10 for sICAM-1, h2=0.22+/-0.10 for sVCAM-1, h2=0.50+/-0.11 for sESEL-1, and h2=0.46+/-0.10 for sPSEL-1. In addition, a significant genetic correlation (rho(G)=0.63) was found between sICAM-1 and sVCAM-1 indicating some degree of shared genetic control. In the Fels Longitudinal Study, the levels of four sCAMs are significantly influenced by genetic effects, and sICAM-1 shares a common genetic background with sVCAM-1.

ICAM G241A polymorphism and soluble ICAM-1 serum levels: evidence for an active immune process in schizophrenia

OBJECTIVES

We have previously reported reduced serum levels of soluble intercellular adhesion molecule-1 (sICAM-1) in schizophrenic patients. A single-nucleotide polymorphism (SNP) of the ICAM-1 gene was described at position 241. The G-->A SNP results in a nonsynonymous amino acid exchange of the ICAM-1 protein, and the A allele was shown to be also associated with several immunological disorders like rheumatoid arthritis.

METHODS

We investigated 70 schizophrenic patients and 128 unrelated healthy control persons regarding the relationship between the serum levels of sICAM-1 and the ICAM-1 G214A polymorphism.

RESULTS

We were able to replicate our previous finding of reduced sICAM-1 levels in schizophrenia. Healthy control persons carrying the polymorphic A allele showed markedly lower sICAM-1 serum levels than carriers of the homozygous GG wild type (p < 0.004). In contrast, no significant difference in the sICAM-1 serum levels were seen regarding the G241A genotype distribution in schizophrenic patients.

CONCLUSION

We hypothesize that the biochemical effect of the G241A SNP is masked in schizophrenic patients, indicating a disease-related mechanism leading to reduced levels of sICAM-1 in schizophrenia.

Intercellular adhesion molecule-1 polymorphisms in Korean patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is characterized by synovial proliferation and the accumulation of inflammatory cells in the affected joints. Intercellular adhesion molecule-1 (ICAM-1) is readily detected in RA synovial tissues and helps recruit inflammatory cells to the joint. ICAM-1 shows genetic polymorphisms at codons 241 (R241G) and 469 (K469E). In order to investigate the association between ICAM-1 gene polymorphisms and RA, we genotyped ICAM-1 R241G and ICAM-1 K469E polymorphisms in 143 Korean patients with RA, and in 138 healthy controls, by using the polymerase chain reaction-restriction fragment length polymorphism method. No polymorphism of R241G was found in Korean subjects. However, the frequency of the K469 allele was found to be significantly lower in RA patients than in healthy controls. Allele frequency of K469 was lower in RA patient group, compared to that in healthy controls, regardless of the shared epitope status. Distribution of K469E allele frequencies was not different whether the patient had rheumatoid factor, radiographic erosion or extra-articular complications. In conclusion, this study shows lower frequency of the ICAM-1 K469E allele in Korean patients with RA than that in healthy controls.