© 1999 American Heart Association, Inc.
Atherosclerosis and Lipoproteins |
A Common Mutation of the Insulin Receptor Substrate-1 Gene Is A Risk Factor for Coronary Artery Disease
From the Istituto di II Clinica Medica (M.G.B., M.P.D., E.M., S.L., P.P.), Istituto di Terapia Medica Sistematica (A.M., F.C., G.R., G U., M.A.), IInd Cattedra di Cardiologia (G.P., F.B., P.C.), and Istituto di Chirurgia del Cuore e dei Grossi Vasi (G.P.), University of Rome "La Sapienza," and the Laboratorio di Epidemiologia e Biostatistica (F.S.), Istituto Superiore di Sanità, Rome, Italy.
Correspondence to Marco Giorgio Baroni, MD, PhD, II Clinica Medica, University of Rome "La Sapienza," Policlinico Umberto I, Viale del Policlinico 155, 00161 Rome, Italy. E-mail baroni{at}caspur.it
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Abstract |
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Abstract—Insulin resistance is associated with increased risk of atherosclerosis. Insulin receptor substrate-1 (IRS-1) plays a key role in tissue insulin sensitivity. A common mutation (G972R) of the IRS-1 gene has been shown to impair IRS-1 function, and it has been associated with reduced insulin sensitivity and lipid abnormalities. This led us to investigate the role of the G972R mutation in predisposing individuals to coronary artery disease (CAD). The DNA of 318 subjects with angiographically documented coronary atherosclerosis (>50% stenosis) and 208 population control subjects was analyzed for the presence of the G972R mutation. This mutation was detected by nested polymerase chain reaction and BstNI restriction enzyme digestion. The frequency of the G972R mutation was significantly higher among patients with CAD than controls (18.9% versus 6.8%, respectively; P<0.001). After controlling for other coronary risk factors, the relative risk of CAD associated with the G972R mutation was 2.93 (95% CI 1.30 to 6.60; P<0.02) in the entire cohort. This risk was found to be even higher in the subgroups of obese subjects (odds ratio [OR] 6.97, 95% CI 2.24 to 21.4; P<0.001) and subjects with clinical features of insulin resistance syndrome (OR 27.3, 95% CI 7.19 to 104.0; P<0.001). The IRS-1 gene variant was associated with a higher frequency of diabetes mellitus (14.9% among carriers versus 6.5% among noncarriers; P<0.01) and with a 60% increase of plasma total triglycerides (P<0.001). Also, plasma concentrations of total cholesterol and the ratio of total cholesterol to HDL cholesterol were significantly (P<0.001) higher among carriers than noncarriers, although to lesser a extent. These effects were independent of CAD status. The G972R mutation in the IRS-1 gene was found to be a significant independent predictor of CAD. Moreover, this mutation greatly increased the risk of CAD in obese subjects and in patients with the cluster of abnormalities of insulin resistance syndrome. Besides the increased frequency of diabetes, carriers showed a more atherogenic lipid profile, suggesting a potential role of the IRS-1 gene in the pathogenesis of lipid abnormalities associated with CAD.
Key Words: insulin resistance • IRS-1 gene • coronary artery disease • obesity • hyperlipidemia • association studies
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Introduction |
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There is increasing evidence that genetic factors contribute significantly to the risk of coronary artery disease (CAD).1 However, except for genetically determined lipid abnormalities, little is known about genetic factors leading to coronary atherosclerosis.2 Insulin resistance and hyperinsulinemia are conditions known to be associated with an increased risk of CAD.3 4 Therefore, genetic variants affecting tissue sensitivity to insulin may represent candidate genes for CAD.
The insulin receptor substrate-1 (IRS-1) gene has been proposed as having a role in the insulin-resistant disorders.5 Its gene product, the IRS-1 protein, is a cytoplasm molecule expressed in most insulin-sensitive tissues and has been demonstrated to play a pivotal role in modulating the cellular effects of insulin.5 6 After the binding of insulin to its receptor, the intrinsic tyrosine kinase activity of the receptor ß-subunit is activated, thus catalyzing the phosphorylation of specific tyrosine residues on the IRS-1 protein. Thereby, phosphorylated IRS-1 binds with high affinity to several cellular signal proteins, thus functioning as a multisite "docking" protein linking the receptor kinase to the variety of cell functions regulated by insulin.7 8
The genetic analysis of the IRS-1 gene has revealed several
base-pair changes that result in amino acid
substitutions.9 10 11 The most common amino acid change is a
glycine to arginine substitution at codon 972 (G972R), which has an
overall frequency of 
6% in the general population.12
This mutation has been reported to significantly impair IRS-1 function
in experimental models,13 and clinical studies have shown
that this genetic variant is associated with reduced insulin
sensitivity.14 Moreover, earlier observations have
indicated that the presence of a mutated IRS-1 gene is associated with
dyslipidemia,14 15 16 further suggesting that
this gene variant may have a significant effect on several risk factors
for CAD.
To investigate whether this common variant of the IRS-1 gene may be a genetic marker for risk of CAD, we studied the distribution of the G972R mutation in patients with angiographically defined coronary atherosclerosis and assessed its relation with clinical and metabolic abnormalities.
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Methods |
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Subjects
A total of 526 subjects were included in the present study. The case population consisted of 318 consecutive patients (266 men and 52 women, aged 40 to 78 years) selected for having angiographic evidence of coronary atherosclerosis (one or more stenoses >50% in at least one major coronary artery).17 One hundred fourteen of these patients underwent coronary angiography for myocardial infarction, and 204 for stable or unstable angina. None of them was enrolled during the acute phase of the ischemic syndrome. All angiograms were independently evaluated by 2 cardiologists who did not known that the patients were to be included in the study. Patients with concurrent thyroid, liver, or renal disease and those on lipid-lowering medications were excluded. Control subjects were 208 unrelated individuals (108 men and 100 women, aged 40 to 80 years) randomly selected from a population of free-living individuals screened for coronary risk factors. In these subjects, CAD was excluded by the Rose questionnaire and ECG (Minnesota coding),18 the use of which to classify CAD patients for population-based screenings has been well established.18 A structured questionnaire was used to characterize both case patients and controls. History included questions about known CAD risk factors (smoking habits, alcohol consumption, and exercise habits), medical history (hypertension, diabetes, and cardiac history), and current medications. Diagnosis of non—insulin-dependent diabetes mellitus (NIDDM) was based on history of hypoglycemic treatment and/or fasting blood glucose >7.8 mmol/L (140 mg/dL)19 ; diagnosis of hypertension was based on the presence of elevated systolic (>160 mm Hg) and/or diastolic (>95 mm Hg) blood pressure and/or the current use of antihypertensive drugs. Data collection included height and weight (to determine body mass index [BMI], assessed as weight in kilograms divided by height2 in meters) and systolic and diastolic blood pressures. Fasting blood samples for laboratory measurements and DNA isolation were obtained early in the morning after an overnight fast.
DNA Analysis
Blood was collected in 10 mL Na-EDTA and kept frozen at
-20°C. DNA was extracted by the salting-out method20
and stored at 4°C in 10 mmol/L Tris-HCl and 1 mmol/L EDTA
(pH 8.0) until analysis. To ensure privacy, DNA extraction and
analysis were carried out anonymously with the use of code
numbers.
The presence of a glycine to arginine substitution at codon 972 of the
IRS-1 gene (G972R) was determined according to the method of Almind et
al9 with some modifications. A primary polymerase chain
reaction (PCR) was performed in a final volume of 25 µL containing
100 to 200 ng of genomic DNA, 200 µmol/L dNTPs, 1.5
mmol/L MgCl2, 0.2 µmol/L of primers, and
0.05 U of Taq DNA polymerase (Applied Biotechnologies) in the standard
buffer. Sequences of primers have been already reported.10
A standard thermocycling procedure was carried out at annealing
temperatures of 64°C for 1 minute. In this primary PCR reaction,
fragments of 479 bp were amplified. A secondary nested PCR reaction was
performed with 1 µL of a 1:10 diluted primary PCR product as
template. Primers for this second PCR were those described by Almind et
al.9 A fragment of 263 bp was obtained during the
secondary PCR. Restriction enzyme digestion was carried out at 60°C
for 12 hours in 15 µL reaction buffers containing 10 µL of the
secondary PCR product, 1.5 µL of 10x NEB buffer 2 (New England
Biolabs Inc), and 10 U of the restriction enzyme BstNI (New
England Biolabs Inc). The fragments were analyzed by 4.5%
high-resolution agarose gel electrophoresis. Digestion patterns
obtained in wild-type and heterozygous IRS-1 mutation carriers are
shown in Figure 1
. Genotypes were
scored by 2 independent investigators who did not know whether the
samples were from a case patient or from controls. Ambiguous samples
were analyzed a second time.
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Other Laboratory Measurements and Techniques
Cholesterol and triglyceride
concentrations in whole plasma and lipoprotein fractions were measured
with a Technicon RA-1000 Autoanalyzer. HDL
cholesterol was determined in the whole plasma after
precipitation of apoB-containing lipoproteins with phosphotungstic
acid/MgCl2.21 Plasma glucose was
measured with a glucose oxidase method adapted for the Technicon
RA-1000 Autoanalyzer. Plasma insulin concentrations were
measured in frozen samples by radioimmunoassay (Biodata Insulin Kit).
The interassay coefficient of variation was 7.5%.
Statistical Analysis
The means were compared by ANOVA or the 2-tailed Student
t test. For comparing discrete variables,
2 analysis or the Fisher exact test
was used. Logarithmic transformation was used to normalize distribution
of plasma triglycerides and insulin values. All comparisons
were made after age and sex standardization. The frequencies of the
alleles and genotypes in case patients and controls were
determined by direct count and compared by the
2 test with the values predicted assuming
Hardy-Weinberg equilibrium. To estimate the relative risk of CAD
associated with IRS-1 genotypes, odds ratios (ORs) were
calculated by multivariate analysis. These
analyses were performed in the whole group as well as in the
subgroups of obese subjects and of those showing features of
insulin-resistance syndrome (IRS). Obese subjects were defined on the
basis of a BMI value >25 kg/m2. Subjects with
IRS were defined as those showing at least 2 of the following clinical
characteristics: hypertension, obesity, high triglycerides
(>2.26 mmol/L [200 mg/dL]),22 and high
fasting insulin (>9.2 µU/mL, corresponding to the 75th percentile of
fasting insulin distribution in the controls). Age, sex, smoking,
obesity, total cholesterol, hypertension, diabetes, and
fasting insulin were included in the logistic model as confounding
variables. Obesity, hypertension, and fasting insulin were not
considered for adjustment in the obese and IRS subgroups. For each OR,
a 2-tailed probability value and 95% confidence intervals were
estimated. The association of concomitant variables with
genotypes was tested by 1-way ANOVA. Data for continuous
variables were expressed as mean±SD; a 2-tailed value of
P<0.05 was considered statistically significant. Bonferroni
correction was used for repeated measurements. All computations were
carried out with the BMDP Statistical package.
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Results |
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Study Subjects
The distribution of selected risk factors in CAD patients and controls are reported in Table 1
.
The 2 groups were comparable in age, body mass, and prevalence of
menopause. As expected, CAD patients showed significantly higher
frequencies of the classic coronary risk factors, such as male
sex, smoking, hypertension, and diabetes. The prevalence of
hypertriglyceridemia was significantly
higher in CAD patients, whereas
hypercholesterolemia did not differ between the
groups. CAD patients also showed significantly reduced levels of HDL
cholesterol and increased fasting insulin and blood glucose
levels compared with controls. Similar differences were observed when
CAD and control men and women were analyzed separately, except
for BMI, which was significantly higher in CAD men but not in CAD women
with respect to their controls (26.7±3.4 versus 25.6±3.0
kg/m2 [P<0.001] and 27.2±4.1
versus 26.7±3.0 kg/m2 [P<0.4],
respectively). The frequency of users of ß-blockers and/or
diuretics was significantly higher in CAD than in control
subjects (36.5% versus 14.4%, respectively; P<0.01).
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Frequency of G972R Mutation in the IRS-1 Gene
In the total cohort, 74 (14.2%) of 522 subjects were found to be
heterozygous for the G972R mutation in the IRS-1 gene; no homozygous
carrier was found (Table 2). In the CAD
group, the control group, and the total cohort, the observed
frequencies were in Hardy-Weinberg equilibrium. The frequency of G972R
mutation carriers in our control population was 6.8%, which is similar
to that previously reported in normal subjects from different ethnic
groups.12 No sex-related differences were found in
the frequency of the G972R mutation in both case patients and
controls.
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Association Between G972R Mutation and CAD
Genotypes and allele frequencies of G972R
mutation in CAD patients and controls are reported in Table 2
.
This mutation was found to be almost 3 times more frequent in CAD
patients than in controls (18.9% versus 6.8%, respectively), and the
difference was highly significant (2=14.9,
P<0.0001). Also, allele frequencies were significantly
different between the 2 groups (P<0.0002), with the mutated
R allele showing a frequency of 9.5% and of 3.5% in CAD patients
and controls, respectively. ORs were calculated as measure of risk of
CAD attributable to the presence of the G972R mutation by logistic
regression analysis (Table 3).
After controlling for other risk factors, heterozygosity for the R
allele was associated with a significantly higher risk of
coronary atherosclerosis (OR 2.93, 95%
confidence interval 1.30 to 6.60; P<0.01). Sex
(P<0.001), smoking (P<0.001), history of
diabetes (P<0.0005), and fasting insulin
(P<0.001) were strongly and independently associated with
CAD. Also, obesity and hypertension were associated with increased risk
of CAD, although the association did not reach statistical
significance. Total cholesterol was not shown to be
significantly associated with CAD, and this is in agreement with the
lack of difference in the prevalence of
hypercholesterolemia between case patients and
controls.
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To test the potential interaction between the IRS-1 gene variant and
the conditions known to be associated with
hyperinsulinemia and insulin resistance, we
repeated the analyses by subdividing the sample according to
BMI (above or below 25 kg/m2) and to the presence
or absence of IRS. The results, presented in Figure 2, indicate that obesity (BMI >25
kg/m2), per se, did not significantly affect CAD
risk. However, when obesity was associated with the presence of the
G972R mutation, the risk of CAD increased up to 6 times (OR 6.92, 95%
CI 2.24 to 21.4; P<0.001) for these individuals compared
with nonobese/noncarrier individuals. After stratification for IRS, the
affected noncarriers already showed a significantly increased risk of
CAD (OR 5.10, 95% CI 3.04 to 8.58; P<0.001), and this
effect was further enhanced by the presence of the G972R mutation in
the IRS-1 gene (OR 27.3, 95% CI 7.19 to 104.0;
P<0.001).
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Association Between G972R Mutation and Clinical and Metabolic
Characteristics
Table 4 compares clinical and
biochemical data according to the presence of the G972R mutation.
Carrier individuals showed significantly higher values of plasma total
cholesterol (P<0.001) and
triglycerides (P<0.001). These subjects also
showed lower levels of HDL cholesterol, but the difference
was not statistically significant. However, when the ratio of total
cholesterol to HDL cholesterol was estimated,
it was significantly higher in subjects with the mutant IRS-1
allele (P<0.001). Furthermore, diabetes was
significantly more frequent in mutation carriers compared with
wild-type carriers (14.9% versus 6.5%, respectively;
P<0.01). Fasting insulin and glucose concentrations did not
differ between the 2 groups, nor did the prevalence of hypertension. To
exclude the possibility that the differences observed might simply
reflect the presence of CAD, we repeated the comparisons after
stratification for CAD status. Compared with noncarrier CAD subjects
(n=268), CAD carriers of the G972R mutation (n=62) showed increased
concentrations of total cholesterol (5.82±1.05 versus
6.73±1.06 mmol/L, respectively; P<0.01), total
triglycerides (2.02±0.95 versus 3.38±1.34 mmol/L,
respectively; P<0.001), and ratio of total
cholesterol to HDL cholesterol (5.5±1.5 versus
8.2±0.9, respectively; P<0.05). Also, the frequency of
diabetes was higher among CAD subjects with the IRS-1 mutation compared
with those with wild-type IRS-1 (17% versus 7.1%, respectively;
P<0.01).
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Discussion |
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The rationale for including the IRS-1 gene in the list of candidate genes for CAD was based on the demonstration that defects in tissue sensitivity to insulin may cause several metabolic alterations leading to the development of coronary atherosclerosis.4 Because the IRS-1 protein appears to have a pivotal role in modulating tissue response to insulin, a structural defect in this protein may well influence the risk of CAD.
In the present study, subjects with angiographic evidence of coronary atherosclerosis were compared with population controls for whom coronary disease was excluded on the basis of clinical history and noninvasive tests. Even though the possible enrollment of asymptomatic CAD subjects in the control group cannot be definitely ruled out, its effect on comparisons appears to be negligible. In fact, compared with CAD patients, controls showed the expected lower prevalence of risk factors for atherosclerotic disease, similar to that observed in the same age group of the general Italian population.24 Therefore, our control group is representative of the general population of healthy individuals. This is further supported by the observation that the 6.8% frequency of the G972R mutation in controls is very similar to that previously reported in normal subjects.12 A large number of consecutive subjects with well-defined coronary status and the expected higher frequency of classical coronary risk factors were selected as case patients. Sex, diabetes, fasting insulin levels, and smoking were the strongest predictors of coronary stenosis in our cohort. It is noteworthy that hypertriglyceridemia was the most prevalent lipid disorder in our CAD group, a finding already reported in other large angiographically based case-control studies.25 26
We found that the G972R mutation in the IRS-1 gene was significantly associated with increased risk of CAD and that this effect was independent of the other coronary risk factors. Overall, subjects heterozygous for the mutated R allele showed a CAD risk almost 3 times as high as that for wild-type carriers. More notably, the most substantial increase in the risk of CAD was observed within the subgroups of individuals with obesity or IRS, suggesting that the G972R mutation in the IRS-1 gene may worsen or induce these abnormalities.
The mechanisms responsible for these associations remain speculative. We observed that the G972R substitution in the IRS-1 gene was significantly related to a more atherogenic lipid profile as well as to a 2 times higher frequency of diabetes mellitus. Therefore, the association between the IRS-1 mutation and CAD may occur as a result of the possible effect of the IRS-1 gene variant on these risk factors. It is well known that diabetes is a strong risk factor for CAD,27 and previous studies have reported that the G972R mutation is almost twice as frequent in NIDDM patients as in control subjects.12 16 We confirmed this finding, further suggesting that this IRS-1 gene variant might act as a susceptibility gene for NIDDM. However, the multivariate analysis clearly demonstrated that the association of the G972R mutation with increased risk of CAD was independent of diabetes, indicating that additional factors may play a role. We found that the most remarkable change in the lipid profile of mutation carriers was a 60% increase in plasma triglycerides. Also, Clausen et al14 described significantly higher triglyceride levels in heterozygous carriers of the G972R mutation. More recently, hypertriglyceridemia has been shown in homozygous IRS-1–deficient mice, suggesting a direct role of the IRS-1 gene in modulating triglyceride levels.28 Both hyperinsulinemia and insulin resistance are known to predispose individuals to diabetes and hypertriglyceridemia.4 29 However, when we compared fasting insulin levels between carriers and noncarriers, we did not find any significant difference. A similar observation has been reported by others,14 and it may be explained by the fact that fasting insulin is only a crude estimate of individual whole-body insulin sensitivity.30 In the present study, we could not directly measure insulin resistance, but previous reports have established that the G972R substitution in the IRS-1 gene causes insulin insensitivity.14 On the other hand, other possible metabolic effects of IRS-1 should be considered. In this respect, the IRS-1–mediated activation of phosphatidylinositol-3 kinase has been reported to be involved in the antilipolytic effect of insulin.31 Because it has been demonstrated that the G972R substitution significantly reduces the IRS-1–mediated phosphatidylinositol-3 kinase activation,13 it is conceivable that mutation carriers may have impaired antilipolysis. As a consequence, an increased efflux of free fatty acid from adipose tissue would provide more substrate available for VLDL-triglyceride synthesis by the liver.32 In addition, hypertriglyceridemia might be due to defective hydrolysis of plasma triglycerides. This mechanism has been demonstrated in the mouse model of IRS-1 deficiency, in which lipoprotein lipase activity was found to be significantly reduced in both plasma and adipose tissue after heparin administration.28 It is known that increased triglyceride concentration enhances atherogenesis by causing adverse changes in many CAD risk factors.33 Furthermore, it may, per se, reduce tissue insulin sensitivity.34 Although further studies are needed to better define the role of the IRS-1 gene in modulating triglycerides and in fatty acid metabolism, our findings clearly indicate that this IRS-1 gene variant may predispose to proatherogenic alterations in plasma lipids.
An additional interesting finding of the present study was that the G972R mutation significantly contributes to increasing the risk of CAD in subjects with obesity or IRS. This phenomenon was particularly evident in obese subjects, in whom only those carrying the G972R mutation showed a significantly increased risk of CAD. Obesity is associated with CAD risk only in the presence of a visceral distribution of adipose tissue.35 In the present study, we did not assess the regional distribution of body fat, and so far, no data indicating that the presence of IRS-1 variant is associated with the accumulation of visceral adipose tissue are available. Another possibility might be that the G972R mutation represents a genetic marker in obese individuals, who are more predisposed to develop the abnormalities associated with insulin resistance. Additional work is warranted to clarify these important issues. Nevertheless, our results suggest that the identification of the G972R IRS-1 gene mutation might be particularly useful in the presence of obesity or IRS for the detection of individuals at higher risk of CAD.
In conclusion, we demonstrated that a common mutation in the IRS-1 gene may represent a useful genetic marker of increased risk of CAD. Even though the mechanisms underlying this effect cannot be inferred from the present study, our findings suggest that mutations in the IRS-1 gene may increase CAD risk by predisposing individuals to the development of metabolic risk factors such as diabetes and dyslipidemia. Further studies are needed to investigate the clinical and therapeutic implication of our results.
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Acknowledgments |
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This study was supported by grant E252 from Telethon Italy and from the Ente Cassa di Risparmio di Roma (to Dr Baroni) and by grants 95.0000982.PF40, 95.00910.PF41, 96.05269.74, and 95.00924.41 from the Italian National Research Council (CNR) (to Drs Arca and Urbinati). We are indebted to L. Porcu and R. Cantini for their excellent technical support, to Drs A. Barbato and N. Di Lecce for their invaluable contribution to the population screening, and to Dr A. Candeloro for assistance in the recruitment of patients.
Received January 28, 1999; accepted April 9, 1999.
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References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
-
Marenberg ME, Rish N, Berkman LF, Floderus U.
Genetic susceptibility to death from coronary heart disease in
a study of twins. N Engl J Med. 1994;330:1041–1046.
[Abstract/Free Full Text] - Cambien F, Soubrier F. Genetic risk factors for myocardial infarction. In: Mockrin SC, ed. Molecular Genetics and Gene Therapy of Cardiovascular Disease. New York, NY: Marcel Dekker Inc; 1997:239–269.
- Reaven GM. Role of insulin resistance in human disease: Banting Lecture. Diabetes. 1988;37:1595–1607.[Abstract]
- DeFronzo RA, Ferrannini E. Insulin resistance: a multifaceted syndrome responsible for NIDDM, obesity, hypertension, dyslipidemia and atherosclerotic cardiovascular disease. Diabetes Care.. 1991;14:173–194.[Abstract]
- Kahn CR. Insulin action, diabetogenes and the cause of type II diabetes. Diabetes. 1994;43:1066–1084.[Medline] [Order article via Infotrieve]
- Sun XJ, Rothemberg P, Khan CR, Backer JM, Araki E, Wilden PA, Cahill DA, Goldstein BJ, White MF. Structure of the insulin receptor substrate IRS-1 defines a unique signal transduction protein. Nature. 1991;352:73–77.[Medline] [Order article via Infotrieve]
- Meyers MG, White MF. The new elements of insulin signaling: insulin receptor substrate-1 and proteins with SH2 domains. Diabetes. 1993;42:643–650.[Abstract]
- Kanai F, Ito K, Todaka M, Hayashi H, Kamhara S, Ishii K, Okada T, Hazeki O, Ui M, Ebina Y. Insulin-stimulated GLUT4 translocation is relevant to the phosphorylation of IRS-1 and the activity of PI-3 kinase. Biochem Biophys Res Commun. 1993;195:762–768.[Medline] [Order article via Infotrieve]
- Almind K, Bjorbaek C, Vestergaard H, Hansen T, Echwald S, Pedersen O. Amino acid polymorphism of insulin receptor substrate-1 in non-insulin-dependent diabetes mellitus. Lancet. 1993;342:828–832.[Medline] [Order article via Infotrieve]
- Laakso M, Malkki M, Kekalainen P, Kuusisto J, Deeb SS. Insulin receptor substrate-1 variants in non-insulin-dependent diabetes. J Clin Invest. 1994;94:1141–1146.
- Imai Y, Fusco A, Suzuki Y, Lesniak MA, D’Alfonso R, Sesti G, Bertoli A, Lauro R, Accili D, Taylor SI. Variant sequences of insulin receptor substrate-1 in non-insulin-dependent-diabetes mellitus. J Clin Endocrinol Metab. 1994;79:1655–1658.[Abstract]
- Hitman GA, Hawrami K, McCarthy MI, Viswanathan M, Snehalatha C, Ramachandran A, Tuomilehto J, Tuomilehto-Wolf E, Nissinen A, Pedersen O. Insulin receptor substrate-1 gene mutations in NIDDM: implications for the study of polygenic disease. Diabetologia. 1995;38:481–486.[Medline] [Order article via Infotrieve]
- Almind K, Inoue G, Pedersen O, Kahn CR. A common amino acid polymorphism in insulin receptor substrate-1 causes impaired insulin signaling: evidence from transfection studies. J Clin Invest. 1996;97:2569–2575.[Medline] [Order article via Infotrieve]
- Clausen JO, Hansen T, Bjorbaek C, Echwald SM, Urhammer SA, Rasmussen S, Andersen CB, Hansen L, Almind K, Winther K, Haraldsdottir J, Borch-Johnsen K, Pedersen O. Insulin resistance: interactions between obesity and a common variant of insulin receptor substrate-1. Lancet. 1995;346:397–402.[Medline] [Order article via Infotrieve]
- Campagna F, D’Andrea MP, Baroni MG, Montali A, Simoni ML, Porcu L, Ricci G, Urbinati GC, Arca M. Genetic determinants of dyslipidemia associated with the insulin resistance syndrome (IRS). Atherosclerosis. 1997;135(suppl 1):S7. Abstract.
- Zang Y, Wat N, Stratton IM, Warren-Perry MG, Orho M, Groop L, Turner RC. UKPDS19: heterogeneity in NIDDM: separate contribution of IRS-1 and beta3-adrenergic-receptor mutations to insulin resistance and obesity respectively with no evidence for glycogen synthase gene mutations. Diabetologia. 1996;39:1505–1511.[Medline] [Order article via Infotrieve]
- Austen WG, Edwards JE, Frye RL. A reporting system on patients evaluated for coronary artery disease: report of the ad hoc committee for grading of coronary artery disease, Council on Cardiovascular Surgery, American Heart Association. Circulation. 1975;51(suppl IV):IV-5–IV-40.
- Rose GA, Blackburn H. Cardiovascular Survey Methods. No. 56. 1st ed. Geneva, Switzerland: World Health Organization; 1968.
- National Diabetes Data Group. Classification and diagnosis of diabetes mellitus and other categories of glucose intolerance. Diabetes. 1979;28:1039–1057.[Medline] [Order article via Infotrieve]
-
Miller SA, Dykes DD, Polesky HF. A simple salting-out
procedure for extracting DNA from human nucleated cells. Nucleic
Acids Res. 1988;16:1215.
[Free Full Text] - Department of Health, Education and Welfare. Lipid and lipoprotein analysis. In: Manual of Laboratory Operations: Lipid Research Clinics Program. Washington, DC: Department of Health, Education, and Welfare; 1984. Publication NIH/F5–628.
- NIH Consensus Development Panel on Triglycerides, High-Density Lipoprotein, and Coronary Heart Disease. Triglyceride, high-density lipoprotein, and coronary heart disease. JAMA. 1993;269:505–510.[Medline] [Order article via Infotrieve]
- Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Summary of the second report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation and Treatment of High Cholesterol in Adults (APT II). JAMA. 1993;269:3015–3023.[Medline] [Order article via Infotrieve]
- Menotti A, Seccareccia F, Lanti MD, RIFLE Project Research Group. Mean levels and distributions of some cardiovascular risk factors in Italy in the 1970’s and 1980’s: the Italian RIFLE Pooling Project: risk factors and life expectancy. G Ital Cardiol. 1995;25:1539–1572.[Medline] [Order article via Infotrieve]
- Genest JJ, McNamara JR, Salem DN, Schaefer EJ. Prevalence of risk factors in men with premature coronary artery disease. Am J Cardiol. 1991;67:1185–1189.[Medline] [Order article via Infotrieve]
-
Reed D, Yano K. Predictors of arteriographically
defined coronary stenosis in the Honolulu Heart
Program. Am J Epidemiol. 1991;134:111–122.
[Abstract/Free Full Text] - The International Task Force for Prevention of Coronary Heart Disease. Coronary heart disease: reducing the risk. Nutr Metab Cardiovasc Dis. 1998;8:205–271.
- Abe H, Yamada N, Kamata K, Kuwaki T, Shimada M, Osuga J, Shionoiri F, Yahagi N, Kadowaki T, Tamemoto H, Ishibashi S, Yazaki Y, Makuuchi M. Hypertension, hypertriglyceridemia, and impaired endothelium-dependent vascular relaxation in mice lacking insulin receptor substrate-1. J Clin Invest. 1998;101:1784–1788.[Medline] [Order article via Infotrieve]
- Ferrannini E, Haffner SM, Mitchell BD, Stern MP. Hyperinsulinaemia: the key feature of cardiovascular and metabolic syndrome. Diabetologia. 1991;34:416–422.[Medline] [Order article via Infotrieve]
-
Laakso M. How good a marker is insulin level for
insulin resistance? Am J Epidemiol. 1993;137:959–965.
[Abstract/Free Full Text] - Okada T, Kawano Y, Sakakibara T, Hazeki O, Ui M. Essential role of phosphatidylinositol-3' kinase in insulin induced glucose transport and antilipolysis in rat adipocytes. J Biol Chem. 1994;5:3568–3573.
- Bjorntorp P. Fatty acids, hyperinsulinemia and insulin resistance: which comes first? Curr Opin Lipidol. 1994;5:166–174.[Medline] [Order article via Infotrieve]
-
Austin MA. Plasma triglycerides and
coronary heart disease. Arterioscler Thromb. 1991;11:2–14.
[Abstract/Free Full Text] - Ferrannini E, Barrett EJ, Bevilacqua S, De Fronzo RA. Effect of fatty acids on glucose production and utilisation in men. J Clin Invest. 1983;72:1737–1747.
-
Després JP, Moorjani S, Lupien PJ, Tremblay A,
Nadeau A, Bouchard C. Regional distribution of body fat, plasma
lipoproteins and cardiovascular disease.
Arteriosclerosis. 1990;10:497–511.
[Abstract/Free Full Text]
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