Relationship Between Angiotensin-Converting Enzyme Gene Insertion or Deletion Polymorphism and Insulin Sensitivity in Healthy Newborns

Download (0)

Full text

(1)

ARTICLE

Relationship Between Angiotensin-Converting

Enzyme Gene Insertion or Deletion Polymorphism

and Insulin Sensitivity in Healthy Newborns

Tongyan Han, MD, PhD, Xinli Wang, MD, PhD, Yunpu Cui, MD, PhD, Hongmao Ye, MD, Xiaomei Tong, MD, Meihua Piao, MD

Department of Pediatrics, Third Hospital, Peking University, Beijing, China

The authors have indicated they have no financial relationships relevant to this article to disclose.

ABSTRACT

CONTEXT.It was proposed that the association between low birth weight and adult insulin resistance is principally genetically mediated. The insertion/deletion poly-morphism of the angiotensin-converting enzyme gene was associated with insulin sensitivity in adults.

OBJECTIVE.Our goal was to investigate the relationship between angiotensin-con-verting enzyme gene insertion/deletion polymorphism and the insulin sensitivity in healthy newborns.

PATIENTS AND METHODS.One hundred eighty healthy newborns, all of whom had a

1-minute Apgar score of⬎7 and gestational age⬎33 weeks, were enrolled in the

study. Fasting glucose and insulin levels were measured on day 2 or 3 after birth, and angiotensin-converting enzyme genotype was determined.

RESULTS.The observed frequency distribution of angiotensin-converting enzyme genotypes did not deviate from that predicted by Hardy-Weinberg equilibrium in this group. There were no statistically significant differences in birth size and shape in different angiotensin-converting enzyme genotypes. Those carriers of the ge-notype homozygous for the deletion allele had the highest logarithmically trans-formed homeostasis model assessment compared with those who were heterozy-gous or homozyheterozy-gous for the insertion polymorphism. When compared with those

withⱖ1 insertion allele, those of the genotype homozygous for the deletion allele

had significantly higher logarithmically transformed fasting insulin and logarith-mically transformed homeostasis model assessment results. Regarding birth weight, birth length, ponderal index, and fasting glucose concentration, there were no significant differences between the genotype homozygous for the deletion allele and the genotypes heterozygous or homozygous for the insertion allele.

CONCLUSIONS.In this study, the deletion allele was associated with relatively impaired insulin sensitivity in healthy neonates. It may be a clue to explain the association between the deletion allele and insulin resistance in the long-term.

www.pediatrics.org/cgi/doi/10.1542/ peds.2006-3297

doi:10.1542/peds.2006-3297

Key Words

ACE gene insertion/deletion

polymorphism, D allele, healthy newborns, insulin sensitivity

Abbreviations

RAS—renin-angiotensin system ACE—angiotensin-converting enzyme I/D—insertion/deletion

ID— heterozygous for the I allele II— homozygous for the I allele DD— homozygous for the D allele FI—fasting insulin

PCR—polymerase chain reaction HOMA— homeostasis model assessment PI—ponderal index

Accepted for publication Feb 12, 2007

Address correspondence to Tongyan Han, MD, PhD, Department of Pediatrics, Third Hospital, Peking University, Beijing 100083, P. R. China. E-mail: tyhan66@yahoo.com.cn

(2)

I

MPAIRED INSULIN SENSITIVITYand insulin resistance are thought to contribute to the development of the pen-tad of hypertension, hyperinsulinism, dyslipidemia, obe-sity, and cardiovascular disease, known as metabolic

syndrome.1There is increasing evidence that insulin

re-sistance is programmed during fetal development. In

1992, Hales and Barker2proposed the “thrifty phenotype

hypothesis,” which postulates that all features of meta-bolic syndrome have a strong environmental basis. It suggests that fetal and early nutrition play an important role in determining the susceptibility of an individual to these diseases. Since then, most studies about low birth weight infants proved that a poor intrauterine environ-ment starts a process of adaptation (programming) to unfavorable environments in the fetus, and this process asserts itself especially at the hormonal level, such as in adrenal medulla, the hypothalamus-pituitary axis, and the renin-angiotensin systems (RASs). Seven years later,

Hattersley and Tooke3proposed that the association

be-tween low birth weight and adult insulin resistance was principally genetically mediated. Low birth weight, mea-sures of insulin resistance in life, and ultimately glucose intolerance, diabetes, and hypertension would all be phenotypes of the same insulin resistant genotype. Both genetics and the fetal environment are likely to be im-portant in determining fetal growth in the same way that both genetic and environmental influences are im-portant in adult disease susceptibility.

RASs play an important role in circulatory homeosta-sis. Angiotensin-converting enzyme (ACE) generates an-giotensin II, a pressor, directly through vasoconstriction and indirectly through stimulation of adrenal aldoste-rone release and resultant salt and water retention. In addition, ACE degrades vasodilator kinins. The inser-tion/deletion (I/D) polymorphism of the ACE gene is characterized by the presence (I) or absence (D) of a 287-base pair alu repeat sequence within intron 16 of

the ACE gene. This polymorphism accounts for nearly

half the variance in serum ACE levels.4Tissue ACE

ac-tivity is similar among those heterozygous for the I allele (ID) and homozygous for the I allele (II), with homozy-gous for the D allele (DD) associated with an elevation in tissue ACE activity of as much as 75% in the heart and

white blood cells.5,6 The increased ACE level was

sug-gested by some but not all studies to predispose to

sev-eral common cardiovascular and renal diseases,7–9

espe-cially in people with diabetes.9,10The view that the RAS

is contained in the placenta and that the RAS is a factor in fetal growth as shown by the identification of

recep-tors in trophoblast layers has gained significance.11As in

adult studies, an association between the RAS or DD

carriers and insulin sensitivity was reported.12,13

Cam-bien et al14found that the ACE genotypes were

associ-ated insulin response among a group of young adults who were born small-for-gestational-age, which

sup-ported the “fetal insulin hypothesis.”3 However, their

results were confined to small-for-gestational-age in-fants. In our study, we explored whether there was an association between ACE gene I/D polymorphism and insulin sensitivity in healthy newborns to find some clues of genetic basis of insulin resistance that excluded the influences of environments (intrauterine, diet, life-style, and disease). Therefore, the aims of our study were to (1) measure fasting insulin (FI) and fasting glucose levels in healthy newborns, (2) determine the relation

between ACE gene polymorphism and infant birth

weight and shape, and (3) investigate the relation

be-tweenACEgene polymorphism and insulin sensitivity in

healthy newborns.

METHODS

Sample

The subjects in our study were recruited from singleton newborns who were delivered from April through De-cember 2003 in the department of obstetrics of the Third Hospital, Peking University. Newborns were included in this study if they fulfilled the following inclusion criteria: (1) they had experienced a normal pregnancy with

ges-tational age of ⬎33 weeks; (2) they had a 1-minute

Apgar score of⬎7 and a 5-minute Apgar score of 10; (3)

they were breastfed during the study; and (4) there was a genomic DNA sample that could be used for genotyp-ing. Newborns were excluded if they were born to women with diabetes, gestational diabetes, gestational hypertension, or chronic hypertension and they had intrauterine infections and congenital malformations. All studies were performed after parents gave written informed consent; the study protocol was approved by the Third Hospital Ethics Committee. The investigation conformed to the principles outlined in the Declaration of Helsinki as revised in 2000.

Measures

Birth Weight and Length

Midwives measured the birth weights and crown-to-heel lengths within 2 hours of delivery. Birth weights were recorded to the nearest gram by using a balance scale.

Fasting Glucose and Insulin Concentrations

All of the neonates were breastfed since birth. Blood was obtained by heel prick before feeding between 7:00 and

9:30 AM on day 2 or 3 of life (ⱖ3 hours’ fast) and

analyzed for glucose and insulin concentration.

(3)

assay was 0.26␮IU/mL (1.81 pmol/L) in our laboratory, and the intraassay and interassay coefficients of varia-tion were 2.6% and 5.2%, respectively.

Genotype of ACE Gene

Genomic DNA was prepared from heel-prick blood (300

␮L) by using a commercially available DNA isolation kit

(Wizard genomic DNA purification kit; Promega, Madi-son, WI). The DNA concentration was adjusted to 100

ng/␮L by adding distilled water. The presence of the

insertion and deletion allele in intron 16 of the ACE

gene was detected using the method of Rigat et al.4The

sequence of sense oligonucleotide primer was 5⬘-CTG

GAG ACC ACT CCC ATC CTT TCT-3⬘and the antisense

primer 5⬘-GAT GTG GCC ATC ACA TTC GTC AGA-3⬘.

The polymerase chain reaction (PCR) was performed with 200 ng of genomic DNA template in a final volume

of 25␮L containing 1.5 mmol/L MgCl2, 50 mmol/L KCl,

10 mmol/L Tris-HCl, 10 pmol of each primer, 200

␮mol/L of each deoxyribonucleotide triphosphate, and 1

unit of Taq DNA polymerase (Takara, Shiga, Japan). Amplification was performed by using a DNA thermal cycler (Gene Amp PCR System 9700; Perkin-Elmer, Fos-ter City, CA) with 30 seconds denaturation at 94°C, 45 seconds annealing at 56°C, and 1-minute extension at 72°C for 35 cycles. In the last cycle, the extension step was conducted for 6 minutes. To avoid mistyping of

heterozygotes as DD homozygotes,15 all DD genotype

samples were confirmed by using a pair of primers that produce an amplified product only in the presence of the insertion, which was used to verify the polymorphism:

sense 5⬘-TGG GAC CAC AGC GCC CGC CAC TAC-3⬘

and antisense 5⬘-TCG CCA GCC CTC CCA TGC CCA

TAA-3⬘.16The PCR condition was similar to that

proce-dure for I/D detection, except that the annealing tem-perature was changed to 67°C. All PCR products were visualized after electrophoresis on a 1.5% agarose gel and ethidium bromide staining. Genotyping was per-formed in a blinded fashion.

Statistical Analysis

The previously validated homeostasis model assessment

(HOMA) was used to estimate insulin sensitivity.17

HOMA was calculated from the fasting glucose and in-sulin concentrations according to the equation: HOMA

⫽ [insulin (␮U/mL) ⫻ glucose (mmol/L)]/22.5. Birth

size and shape measures were birth weight, birth length,

and ponderal index (PI⫽[birth weight/birth length3]

100),18studied as continuous variables.

The data are expressed as mean⫾SD. All statistical

analyses were performed by using the Statistical Package for Social Science 10.0 for Windows (SPSS Inc, Chicago, IL). Fasting insulin and HOMA were logarithmically

transformed (log10) before the analysis to approach

nor-mal distribution.

The subjects were primarily divided into 3 groups

according to the 3 ACE genotypes. The statistical differ-ence in genotype distribution and allele frequencies

among the groups was assessed by the Pearson ␹2test.

One-way analysis of variance was used to test for differ-ences in means of phenotypic characteristics between the 3 genotypes (with Bonferroni correction). We fur-ther combined the subjects of ID and II genotypes and compared with the DD carriers. The clinical characteris-tics of the 2 groups were compared by unpaired

Stu-dent’sttest.P⬍.05 was considered statistically

signifi-cant.

RESULTS

One hundred eighty newborns, including 135 term in-fants and 45 preterm inin-fants, were taken into the scope of the study. All of them were Chinese and they were born at term or near term after a normal pregnancy. They had no major neonatal problems and had normal acid-base status at birth. There was no history of mater-nal hypertension, diabetes, or infections. Mean gesta-tional age and birth weight of the study population were

37.65 ⫾ 2.16 weeks and 2946.46 ⫾ 645.75 g,

respec-tively. The male/female ratio was 101:79.

All newborns were genotyped for the ACE I/D poly-morphism. Because the ACE genotype distributions were not significantly different between term infants

and preterm infants (␹2 ⫽ 1.090;P.580), we

com-bined their data and analyzed them as 1 group. The frequencies of DD, ID, and II genotypes were 18.3%, 46.7%, and 35.0%, respectively. The allele frequencies were 41.67% and 58.33% for the D and I alleles, respec-tively. These results were consistent with the

Hardy-Weinberg equilibrium (␹2⫽ 0.188; P.910).

Demo-graphic characteristics of gender, maternal age,

gestational age, delivery method, and 1-minute Apgar score were not different between genotype groups (Ta-ble 1).

There were no statistically significant differences in birth size and shape in different ACE genotypes (Table 2). And the fasting glucose and fasting insulin (logarith-mically transformed) were not significantly different among the 3 genotypes. The individuals with DD

geno-type had the highest HOMA (log10HOMA ⫽ 0.21 ⫾

0.45) compared with individuals with the ID genotype

(log10HOMA⫽0.01⫾0.38;P⫽0.016) or homozygous

(II) (log10HOMA⫽0.01⫾0.40;P⫽0.021). After using

Bonferroni correction, only the difference between DD genotype and ID genotype was significant.

As shown in Table 2, data for those of ID and II genotypes did not differ. When compared with those

withⱖ1 I allele, those with DD genotype had significant

higher log10FI (0.93 ⫾0.41 vs 0.76⫾ 0.36,P⫽ .018)

and log10HOMA (0.21⫾0.45 vs 0.01⫾0.38,P⫽.010)

(Fig 1). Regarding birth weight, birth length, PI, and fasting glucose concentration, there were no significant

(4)

DISCUSSION

Recruits to this study were born at term or near term after a normal pregnancy, had normal acid-base status at birth, no history of maternal hypertension, and were breastfed during the study. The data were, therefore, not confounded by factors that were reported previously to be associated with serum insulin. The frequencies of ACE genotypes and the frequency of D allele in the study population were not different from those reported in our local population. Despite this relatively homogeneous study population, an evident increased fasting insulin and HOMA (logarithmically transformed) in the DD

ge-notype infants was noted when compared with ID⫹II

genotypes, which suggested an association between the D allele and relatively impaired insulin sensitivity.

The results of our study raise the possibility that the ACE genotype is related to insulin sensitivity. However, previous adult studies have reported conflicting results.

Perticone et al19reported that in a group of never-treated

hypertensive individuals with the DD genotype were more insulin resistant as determined by the HOMA method than those individuals with either the ID or II

genotype groups. Katsuya et al20 reported that normal

subjects with the DD genotype were more insulin sen-sitive and had a lower insulin response to oral glucose

administration. Panahloo et al12 found no influence of

ACE genotypes on insulin sensitivity evaluated by plasma proinsulin levels and HOMA in nondiabetic sub-jects.

The ability of the ACE genotype to influence glucose metabolism is not understood; 1 possible mechanism explaining the link may be the elevated ACE levels that are associated with the DD genotype. Genetic analyses

on I/D polymorphism of the ACE gene showed that

circulating and tissue ACE levels were higher in subjects with the DD genotype than in subjects with other

geno-types.21However, because the ACE I/D polymorphism is

intronic, the mechanism of ACE overexpression in sub-jects with DD genotype is unclear; it is possible that this relationship is the result of tight linkage to another locus

involved in the regulation ofACEgene expression.22

Previous studies found that elevated ACE levels were

associated with diabetes mellitus.23As the main

metab-TABLE 1 Comparison of Demographic Characteristics According to ACE Genotypes

ACE Genotypes ␹2/F P

DD (n⫽33) ID (n⫽84) II (n⫽63)

Male,n(%)a 21 (63.6) 40 (47.6) 40 (63.5) 4.612 .100

Maternal age, mean⫾SD, yb 28.795.04 28.495.05 28.844.04 0.114 .892

Vaginal delivery,n(%)a 22 (67.3) 62 (73.8) 44 (69.8) 9.446 .150

Gestational age, mean⫾SD, wkb 37.512.08 37.962.15 37.312.18 1.694 .187

Apgar score at 1 min, mean⫾SDb 9.730.63 9.740.64 9.780.58 0.101 .904

Comparisons were performed withaPearson’s␹2orbanalysis of variance.

TABLE 2 Comparison of Birth Size and Shape and Metabolic Characteristics According to ACE Genotypes

ACE Genotypes F P

DD (n⫽33) ID (n⫽84) II (n⫽63)

Birth weight, g 2858.18⫾616.70 2982.50⫾638.95 2944.63⫾674.64 0.437 .647

Birth length, cm 48.09⫾3.46 48.67⫾2.77 48.29⫾3.10 0.538 .585

PI 2.54⫾0.26 2.55⫾0.29 2.57⫾0.25 0.160 .852

Fasting glucose, mmol/L 4.44⫾1.40 4.14⫾0.94 4.10⫾1.08 1.168 .313

FI, mIU/L 13.22⫾14.52 7.99⫾8.09 7.85⫾5.10 — —

Log10FI 0.93⫾0.41 0.75⫾0.37 0.77⫾0.38 2.865 0.060

HOMA 3.03⫾5.34 1.46⫾1.46 1.46⫾1.05 — —

Log10HOMA 0.21⫾0.45 0.01⫾0.38 0.01⫾0.40 3.377 0.036

Data are expressed as mean⫾SD. Fasting insulin and HOMA were logarithmically transformed (log10) before the analysis to approach normal distribution. All statistical comparisons were performed with analysis of variance. — indicates not applicable.

FIGURE 1

Comparison of log10FI and log10HOMA between DD genotype and ID⫹II genotypes.

(5)

olite of serum ACE activity, angiotensin II was found to be a modulator of insulin sensitivity in both diabetic and

nondiabetic subjects.24,25ACE inhibitors improve insulin

sensitivity in noninsulin dependent diabetes mellitus

pa-tients,26nondiabetic hypertensive patients,27and

nondi-abetic normotensive subjects.28 These findings suggest

the possibility that elevated ACE levels are associated with reduced insulin sensitivity and glucose intolerance, which contributes to the development of metabolic syn-drome.

It was proposed that the RAS has a pivotal role in fetal development and growth, which is contained in the placenta as shown by the identification of receptors in

trophoblast layers.11,29Studies have shown that the RAS

and angiotensin II are fetal growth factors that have a significant role in the regulation of uteroplacental blood flow by means of angiotensin receptors, as well as in

decidualization, placentation, and implantation.11,29

Moreover, ACE activation was suggested to result in redistribution of the placental circulation and thus

prob-ably reduced nutrient transfer to the fetus.30Therefore,

the carrier of DD genotype, with relatively higher ACE concentration, is associated with increased risk of growth restriction. In our study, we failed to find any significant differences in birth size and shape between 3 ACE genotypes, although the carriers of DD genotype had a tendency to be lighter and smaller. This may because of the limited number of subjects examined and only healthy newborns were included in the study.

CONCLUSIONS

In this group of healthy term and near-term neonates, DD genotype carriers had a significantly increased fast-ing insulin and HOMA, which suggested that the D allele was associated with relatively impaired insulin sensitiv-ity. This fact may provide genetic evidence for the clus-tering of metabolic syndrome or insulin resistance syn-drome and may be a clue to explain the association between the D allele and insulin resistance in the long-term. Because of the limitation of the study, we believe that a larger sample size with more small-for-gestation-al-age infants as a control group addressing the impact of ACE genotype on insulin sensitivity could provide a more robust result.

REFERENCES

1. Reaven GM. Role of insulin resistance in human disease (syn-drome X): an expanded definition. Annu Rev Med.1993;44: 121–131

2. Hales CN, Barker DJP. Type 2 (non-insulin-dependent) diabe-tes mellitus: the thrifty phenotype hypothesis. Diabetologia.

1992;35:595– 601

3. Hattersley AT, Tooke JE. The fetal insulin hypothesis: an alter-native explanation of the association of low birthweight with diabetes and vascular disease.Lancet.1999;353:1789 –1792 4. Rigat B, Hubert C, Alhenc-Gelas F, Cambien F, Corvol P,

Sou-brier F. An insertion/deletion polymorphism in the

angioten-sin-1-converting enzyme gene accounting for half the variance of serum enzyme levels.J Clin Invest.1990;86:1343–1346 5. Danser AHJ, Schalekamp MADH, Bax WA, et al.

Angiotensin-converting enzyme in the human heart: effect of the deletion/ insertion polymorphism.Circulation.1995;92:1387–1388 6. Costerousse O, Allegrini J, Lopez M, Alhenc-Gelas F.

Angio-tensin-I converting enzyme in human circulating mononuclear cells: genetic polymorphism of expression in T-lymphocytes.

Biochem J.1993;290:33– 40

7. Cambien F, Evans AE. The angiotensin-I converting enzyme (ACE) gene polymorphism and coronary heart disease. Eur Heart J.1995;16(suppl K):13–22

8. Yoshida H, Mitarai T, Kawamura T, et al. Role of the deletion polymorphism of the angiotensin converting enzyme gene in the progression and therapeutic responsiveness of IgA ne-phropathy.J Clin Invest.1995;96:2162–2169

9. Keavney BD, Dudley CRK, Stratton IM, et al. UK Prospective Diabetes Study (UKPDS) 14: association of angiotensin-converting enzyme insertion/deletion polymorphism with myo-cardial infarction in NIDDM.Diabetologia.1995;38:948 –952 10. Hsieh MC, Lin SR, Hsieh TJ, et al. Increased frequency of

angiotensin-converting enzyme DD genotype in patients with type 2 diabetes in Taiwan.Nephrol Dial Transplant. 2000;15: 1008 –1013

11. Nielsen AH, Schauser KH, Poulsen K. Current topic: the utero-placental renin-angiotensin system. Placenta. 2000;21: 468 – 477

12. Panahloo A, Andre`s C, Mohamed-Ali V, et al. The insertion allele of the ACE gene I/D polymorphism: a candidate gene for insulin resistance?Circulation.1995;92:3390 –3393

13. Chiu KC, McCarthy JE. The insertion allele of the angiotensin I-converting enzyme gene locus is associated with insulin re-sistance.Metabolism.1997;46:395–399

14. Cambien F, Le´ger J, Mallet C, Le´vy-Marchal C, Collin D, Czerni-chow P. Angiotensin I-converting enzyme gene polymorphism modulates the consequences of in utero growth retardation on plasma insulin in young adults.Diabetes.1998;47:470 – 475 15. Shanmugam V, Sell KW, Saha BK. Mistyping ACE

heterozy-gotes.PCR Methods Appl.1993;3:120 –121

16. Fogarty DG, Maxwell AP, Doherty CC, Hughes AE, Nevin NC. ACE gene typing.Lancet.1994;343:851

17. Matthews DR, Hosker JP, Rudenski AS, Naylor BA, Treacher DR, Turner RC. Homeostatic model assessment: insulin resis-tance and b-sell function from fasting glucose and insulin concentrations in man.Diabetologia.1985;28:412– 419 18. Miller H, Hassanein K. Diagnosis of impaired fetal growth in

newborn infants.Pediatrics.1971;48:511–522

19. Perticone F, Ceravolo R, Iacopino S, et al. Relationship be-tween angiotensin-converting enzyme gene polymorphism and insulin resistance in never-treated hypertensive patients.

J Clin Endocrinol Metab.2001;86:172–178

20. Katsuya T, Horiuchi M, Chen YDI, et al. Relations between dele-tion polymorphism of the angiotensin-converting enzyme gene and insulin resistance, glucose intolerance, hyperinsulinemia, and dyslipidemia.Arterioscler Thromb Vasc Biol.1995;15:779 –782 21. Tiret L, Kee F, Poirier O, et al. Deletion polymorphism in

angiotensin-converting enzyme gene associated with parental history of myocardial infarction.Lancet.1993;341:991–992 22. Davis GK, Roberts DH. Molecular genetics of the

renin-angiotensin system: implications for renin-angiotensin II receptor blockade.Pharmacol Ther.1997;75:43–50

23. Feman SS, Mericle RA, Reed GW, May JM, Workman RJ. Serum angiotensin converting enzyme in diabetic patients.

Am J Med Sci.1993;305:280 –284

(6)

25. Morris AD, Petrie JR, Ueda S, et al. Pressor and subpressor doses of angiotensin II increase insulin sensitivity in NIDDM: dissociation of metabolic and blood pressure effects.Diabetes.

1994;43:1445–1449

26. Jauch KW, Hartl W, Guenther B, Wicklmayr M, Rett K, Dietze G. Captopril enhances insulin responsiveness of forearm mus-cle tissue in non-insulin-dependent diabetes mellitus. Eur J Clin Invest.1987;17:448 – 454

27. Pollare T, Lithell H, Berne C. A comparison of the effects of hydrochlorothiazide and captopril on glucose and lipid metab-olism in patients with hypertension.N Engl J Med.1989;321: 868 – 873

28. Allemann Y, Baumann S, Jost M, et al. Insulin sensitivity in normotensive subjects during angiotensin converting enzyme inhibition with fosinopril. Eur J Clin Pharmacol. 1992;42: 275–280

29. Leung PS, Tsai SJ, Wallukat G, Leung TN, Lau TK. The upregu-lation of angiotensin II receptor AT(1) in human preeclamptic placenta.Mol Cell Endocrinol.2001;26:95–102

30. Knock GA, Sullivan MH, McCarthy A, Elder MG, Polak JM, Wharton J. Angiotensin II (AT1) vascular binding sites in hu-man placentae from normal-term, preeclamptic and growth retarded pregnancies. J Pharmacol Exp Ther. 1994;271: 1007–1015

READERS ARE CHANGING

“The news about newspapers could hardly be more dismal: falling circulation, repeated rounds of layoffs, disappearing ads and a chain of bad earning reports. It’s an unsavory stew of ills, one that shows little prospect of becom-ing more appetizbecom-ing. . . . Perhaps most worrisome is the loss of young readers, who have drifted away steadily since the early 1970s, long before there was an Internet, when more than 70% of 18- to 34-year-old Americans read a daily newspaper. Last year that figure stood at 35%. . . . The time that Americans spend reading newspapers has been dropping steadily (now down to 15 hours a month), with scant evidence that quality Internet time is taking its place. In September, the average visitor to newspaper Web sites spent only 41.5 minutes per month on those sites, up 10% from the previous year but not nearly enough to make up the loss. . . . And while the use of newspaper Web sites is growing, the vast preponderance of Americans get their online news through the big portals (AOL, Yahoo, etc.), which means that they are mostly consuming a bland porridge of wire service stories. . . . Most funda-mental is whether the public is still interested in news (as opposed to entertainment, gossip or lifestyle info). More than fearing the death of newspapers—they will struggle on—we ought to fear what changing reading and viewing habits are forcing newspapers to think of as news. We shouldn’t fault the papers for this, however, any more than we should fault the evening news for going soft or the newsweeklies for their endless lifestyle covers or CNN for its hyperventilating over every weather blip. They’re merely pro-viding what their customers are demanding.”

Rattner S.Wall Street Journal. February 16, 2007

(7)

DOI: 10.1542/peds.2006-3297

2007;119;1089

Pediatrics

Piao

Tongyan Han, Xinli Wang, Yunpu Cui, Hongmao Ye, Xiaomei Tong and Meihua

Deletion Polymorphism and Insulin Sensitivity in Healthy Newborns

Relationship Between Angiotensin-Converting Enzyme Gene Insertion or

Services

Updated Information &

http://pediatrics.aappublications.org/content/119/6/1089

including high resolution figures, can be found at:

References

http://pediatrics.aappublications.org/content/119/6/1089#BIBL

This article cites 30 articles, 8 of which you can access for free at:

Subspecialty Collections

http://www.aappublications.org/cgi/collection/genetics_sub

Genetics

sub

http://www.aappublications.org/cgi/collection/fetus:newborn_infant_

Fetus/Newborn Infant following collection(s):

This article, along with others on similar topics, appears in the

Permissions & Licensing

http://www.aappublications.org/site/misc/Permissions.xhtml

in its entirety can be found online at:

Information about reproducing this article in parts (figures, tables) or

Reprints

http://www.aappublications.org/site/misc/reprints.xhtml

(8)

DOI: 10.1542/peds.2006-3297

2007;119;1089

Pediatrics

Piao

Tongyan Han, Xinli Wang, Yunpu Cui, Hongmao Ye, Xiaomei Tong and Meihua

Deletion Polymorphism and Insulin Sensitivity in Healthy Newborns

Relationship Between Angiotensin-Converting Enzyme Gene Insertion or

http://pediatrics.aappublications.org/content/119/6/1089

located on the World Wide Web at:

The online version of this article, along with updated information and services, is

by the American Academy of Pediatrics. All rights reserved. Print ISSN: 1073-0397.

Figure

TABLE 1Comparison of Demographic Characteristics According to ACE Genotypes

TABLE 1Comparison

of Demographic Characteristics According to ACE Genotypes p.4
TABLE 2Comparison of Birth Size and Shape and Metabolic Characteristics According to ACE Genotypes

TABLE 2Comparison

of Birth Size and Shape and Metabolic Characteristics According to ACE Genotypes p.4
FIGURE 1

FIGURE 1

p.4

References