Serum adiponectin levels, insulin resistance, and lipid profile in children born small for gestational age are affected by the severity of growth retardation at birth

OBJECTIVE: Insulin resistance has been linked to intrauterine growth retardation (IUGR); adiponectin is a protein with insulin-sensitizing properties. This study was designed to test whether being born small for gestational age (SGA) has an effect on blood levels of adiponectin and leptin, insulin resistance parameters, and lipid profile in pre-puberty, taking into consideration the severity of IUGR. METHODS: Serum levels of adiponectin, leptin, total cholesterol (t-CHOL), high density lipoprotein (HDL)-cholesterol, low density lipoprotein (LDL)-cholesterol, triglycerides, apolipoproteins A-1 (Apo A-1), Apo B and Apo E, lipoprotein(a) (Lp(a)), fasting glucose, and insulin (Ins), the homeostasis model assessment insulin resistance index (HOMA-IR) and anthropometric indices were evaluated in 70 children aged 6-8 years, born appropriate for gestational age (AGA; n = 35) and SGA (n = 35), matched for age, gender, height, and BMI. SGA children were divided into two subgroups according to the severity of IUGR: SGA<3rd percentile (n = 20), and SGA 3rd-10th percentile (n = 15). They were also subdivided in two subgroups, those with (n = 25) and those without (n = 10) catch-up growth, considering their actual height corrected for mid-parental height. RESULTS: SGA children had higher Ins and HOMA-IR than AGA children (Ins, 42 +/- 23 vs 32 +/- 11 pmol/l; HOMA-IR, 1.30 +/- 0.8 vs 0.92 +/- 0.3; P<0.05). No significant difference in serum leptin was found between the SGA and the AGA groups but adiponectin showed a trend to be higher in SGA children (13.6 +/- 5.7 vs 10.8 +/- 5.9 microg/ml respectively). SGA children without catch-up growth had higher adiponectin (15.6 +/- 8.5 microg/ml, P<0.05) than AGA children. Among the SGA children, the subgroup <3rd percentile had higher Lp(a) than the subgroup 3rd-10th percentile (P<0.05). An independent positive correlation between adiponectin and Lp(a) was observed in SGA children (R = 0.59, P<0.01). CONCLUSION: SGA children, although more insulin resistant, had similar or higher adiponectin levels than matched AGA children in pre-puberty. The severity of IUGR appears to affect their metabolic profile during childhood.     

Both intrauterine growth restriction and postnatal growth influence childhood serum concentrations of adiponectin

OBJECTIVE: Insulin resistance has been linked to intrauterine growth restriction; adiponectin is a strong determinant of insulin sensitivity. We aimed at studying the contributions of birthweight and insulin sensitivity to circulating adiponectin in children born small for gestational age (SGA). DESIGN: Cross-sectional, hospital-based study dealing with insulin sensitivity in SGA children. PATIENTS: Thirty-two prepubertal children born SGA (age 5.4 +/- 2.9 years) and 37 prepubertal children born appropriate for gestational age (AGA, age 5.9 +/- 3.0 years). MEASUREMENTS: Serum levels of fasting glucose, serum lipids, insulin (immunometric assay) and adiponectin concentrations (ELISA) were assessed, and insulin resistance (IR) and insulin secretion (beta-cell) were calculated by the homeostasis model of assessment (HOMA). RESULTS: SGA children had similar HOMA-IR, HOMA-beta-cell and adiponectin concentrations than AGA children. However, in a separate analysis of subjects older than 3 years of age, SGA children showed higher HOMA-IR after adjusting for sex, age and body mass index (BMI) standard deviation score (SDS). Circulating adiponectin was higher in SGA children [adjusted means: 14.5 mg/l (95% CI 12.9-16.1) and 18.7 mg/l (95% CI 17.0-20.3) for AGA and SGA children, respectively; P < 0.0001]. Further analysis revealed that the group of overweight SGA (arbitrarily defined as being in the higher quartile for the BMI SDS distribution in the sample) had decreased serum concentrations of adiponectin, compared to lean SGA children [adjusted means: 12.9 mg/l (95% CI 9.3-16.5) vs. 19.0 (95% CI 16.8-21.3), respectively; P = 0.001]. In a multiple regression model, HOMA-IR and SGA status explained 35% and 15% of adiponectin variance, respectively. CONCLUSIONS: Prenatal growth restriction is associated with insulin resistance but relatively increased adiponectin concentrations, provided overweight does not ensue. The contributions of circulating adiponectin to the increased risks for developing insulin resistance and type-2 diabetes in formerly SGA subjects merit further studies.     

Longitudinal changes in insulin-like growth factor-I, insulin sensitivity, and secretion from birth to age three years in small-for-gestational-age children

INTRODUCTION: Insulin resistance (IR) develops as early as age 1 to 3 yr in small for gestational age (SGA) infants who show rapid catch-up postnatal weight gain. In contrast, greater insulin secretion is related to infancy height gains. We hypothesized that IGF-I levels could be differentially related to gains in length and weight and also differentially related to IR and insulin secretion. METHODS: In a prospective study of 50 SGA (birth weight < 5th percentile) and 14 normal birth weight [appropriate for gestational age (AGA)] newborns, we measured serum IGF-I levels at birth, 1 yr, and 3 yr. IR (by homeostasis model assessment) and insulin secretion (by short iv glucose tolerance test) were also measured at 1 yr and 3 yr. RESULTS: SGA infants had similar mean length and weight at 3 yr compared with AGA infants. SGA infants had lower IGF-I levels at birth (P < 0.0001), but conversely they had higher IGF-I levels at 3 yr (P = 0.003) than AGA infants. Within the SGA group, at 1 yr IGF-I was associated with length gain from birth and insulin secretion (P < 0.0001); in contrast at 3 yr IGF-I was positively related to weight, body mass index, and IR. CONCLUSIONS: IGF-I levels increased rapidly from birth in SGA, but not AGA children. During the key first-year growth period, IGF-I levels were related to beta-cell function and longitudinal growth. In contrast, by 3 yr, when catch-up growth was completed, IGF-I levels were related to body mass index and IR, and these higher IGF-I levels in SGA infants might indicate the presence of relative IGF-I resistance.     

小于胎龄儿青春前期线性生长方式与血清胰岛素水平关系的研究

目的 探讨小于胎龄儿(small for gestational age,SGA)出生后生长追赶状态与血清胰岛素水平的关系.方法 青春前期30例有生长追赶SGA(catch-up growth SGA,CUG-SGA组)、37例无生长追赶SGA(NCUG-SGA组)和42例适于胎龄儿(appropriate for gestational age,AGA组),测定空腹血糖、空腹胰岛素(FINS)和血清胰岛素样生长因子I(IGF-I).结果 (1)与NCUG-SGA和AGA组比较,CUG-SGA组FINS和稳态模型评估的胰岛素抵抗指数(HOMA-IR)显著为高(P<0.01或P<0.05),而NCUG-SGA组与AGA组则无显著性差异(P>0.05).CUG-SGA组血清IGF-I水平较NCUG-SGA组显著为高[(212.61±17.81对137.40±14.66)ng/ml,P=0.001],但与AGA组无显著性差异(P=0.095).(2)SGA组HOMA-IR与年龄、身高标准差分值增值(AHtSDS)和体重指数分别正相关;≤6岁SGA组FINS与△HtSDS呈正相关,>6岁组FINS与体重标准差分值增值呈正相关.结论 生后早期胰岛素可能以生长因子角色参与了SGA儿的生长追赶;胰岛素抵抗程度与生长追赶程度相随.

Abstract：

Objective To evaluate the association between two different linear growth patterns with the levels of serum insulin in children bem small for gestational age(SGA).Methods Serum fasting glucose,fasting insulin,and insulin-like growth factor-I(IGF-I)concentrations were determined in 30 catch-up growth(CUG)children bern SGA [CUG-SGA,16 females,14males,(6.62±0.66)year],37 non-catch-up growth(NCUG)children born SGA[NCUG-SGA,15 females,22 males,(5.97±0.56)year],and42 appropriate for gestational age(AGA)children with normal height[AGA,16females,26males,(7.05±0.39)year].Results (1) Basal fasting insulin and homeostasis model assessment for insulin resistance(HOMA-IR)were significantly higher in CUG-SGA group than in NCUG-SGA and AGA group(P<0.01 or P<0.05).But there was no difference in fasting insulin between NCUG-SGA group and AGA group.IGF-I levels in CUG-SGA were significantly higher than in NCUG-SGA group[(212.61±17.81 vs 137.40±14.66)ng/ml,P=0.001],but showed no difference from AGA group(P=0.095).(2)In the SGA group,HOMA-IR showed positive correlation with age,△height SDS,and current body mass index.Fasting insulin showed positive correlation with △height SDS(r=0.500,P=0.002)in≤6 year group as well as with △weight SDS(r=0.496,P=0.030)in>6 year group.Conclusions Insulin as a growth factor may participate in postnatal catch-up growth accompanied with increased insulin resistance in SGA children.     

Serum levels of adiponectin and IGFBP-1 in short children born small for gestational age

OBJECTIVE: The aim of this study was to quantify serum adiponectin concentrations in short children born small for gestational age (SGA) compared with those in children born appropriate for gestational age (AGA), and to assess the relationship between the serum levels of adiponectin and insulin-like growth factor binding protein-1 (IGFBP-1) known as a predictor of the development of type 2 diabetes mellitus and cardiovascular disease. SUBJECTS AND METHODS: Sixteen prepubertal short children born SGA and 20 short children born AGA, matched for age, body mass index, height, pubertal status, gestational age, bone age and midparental height, were included in the study. The serum levels of adiponectin, IGFBP-1, insulin and insulin-like growth factor-I (IGF-I) were measured in the fasting state. RESULTS: The levels of serum adiponectin were significantly lower in the SGA than in AGA children (10.5 +/- 4.2 vs. 13.9 +/- 5.1 micro g/ml, P < 0.05). The levels of serum IGFBP-1, insulin and IGF-I were all similar in both groups. Overall, there was a significant positive correlation between adiponectin and IGFBP-1 (r = 0.40, P < 0.05). CONCLUSIONS: Our results suggest that hypoadiponectinaemia in short SGA children without catch-up growth may reflect insulin resistance and imply a higher risk of developing type 2 diabetes mellitus. Additionally, adiponectin may be a more sensitive indicator for latent insulin resistance than IGFBP-1 in short SGA children.     

Blood glucose concentrations are reduced in children born small for gestational age (SGA), and thyroid-stimulating hormone levels are increased in SGA with blunted postnatal catch-up growth

Fetal growth restriction is associated with an increased risk of developing insulin resistance and type 2 diabetes in adulthood. In addition, 10-20% of children born small for gestational age (SGA) do not achieve a normal final height. The purpose of this study was to investigate insulin sensitivity and endocrine status in SGA children, compared with that in children born appropriate for gestational age (AGA). Furthermore, within the SGA group, we aimed to relate postnatal growth to anthropometric, biochemical, and endocrine parameters. Eighty-two SGA children (with a mean age of 8.6 +/- 3.5 yr) and 53 short-AGA children (with a mean age of 9.3 +/- 3.3 yr) were studied. A case-control study was carried out in 26 SGA and 26 short-AGA subjects. For each SGA subject, we selected a short-AGA child matched for sex, age (within 1 yr), pubertal status, body mass index (within 0.5 kg/m(2)), and height (within 0.25 z-score). Children's statures were corrected for their midparental height, and SGA children were subdivided into 2 groups: catch-up growth (CG) group (children with corrected height with at least 0 z-score); and non-CG (NCG) group (subjects with corrected height with less than 0 z-score). Comparing SGA with short-AGA subjects, no significant differences in fasting insulin, fasting glucose/insulin ratio, homeostasis assessment model for insulin resistance, and homeostasis assessment model-beta-cell values were observed. SGA children showed significantly reduced levels of glucose (4.4 +/- 0.6 vs. 4.9 +/- 0.6 mM, P < 0.0001), total cholesterol (160.1 +/- 28.8 vs. 171.8 +/- 28.5 mg/dl, P = 0.02), and high-density-lipoprotein cholesterol (53.3 +/- 12.1 vs. 58 +/- 11.4 mg/dl, P = 0.02). The analysis of the subjects selected for the case-control study confirmed that SGA children did not have significant differences in the indices of insulin sensitivity but showed significantly lower glucose levels (4.4 +/- 0.7 vs. 4.9 +/- 0.4 mM, P < 0.005). Subdividing the SGA group into CG (n = 25) and NCG (n = 57) children, we found that NCG children showed significantly higher levels of TSH (2.5 +/- 1.3 vs. 1.9 +/- 0.6 mU/liter, P = 0.002). Our data indicate that SGA children do not have altered insulin sensitivity when compared with auxologically identical AGA subjects but show a significant reduction of glucose concentrations. Whether the lower glucose levels are attributable to an early phase of augmented insulin sensitivity, as previously reported in animal models, has to be established. The finding of higher TSH concentrations in SGA children with blunted CG suggests that intrauterine reprogramming might involve thyroid function, which, in turn, might affect postnatal growth and cholesterol metabolism, eventually increasing the risk of cardiovascular disease.     

Serum leptin in formerly small-for-gestational-age children during adolescence: relationship to gender, puberty, body composition, insulin sensitivity, creatinine, and serum uric acid

Serum leptin levels reflect body fat mass (FM), and have been described to be related to serum uric acid levels in adult type 2 diabetic and healthy subjects. We therefore aimed to evaluate the interrelationship between leptin and markers of the metabolic syndrome by studying serum leptin concentration, body mass index (BMI), percent body fat (Fat%), total fat mass (FM), sum of skinfolds (SS), triglycerides (TG), total cholesterol (CHOL), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), glucose, insulin, calculated insulin resistance (HOMA), creatinine (CR), and uric acid (UA) concentration in 50 former small-for-gestational-age (SGA) children and 21 infants born adequate for gestational age (AGA) at the time of mid-puberty. Our data confirm previous results showing a positive association between leptin and body fatness, and female gender. Twelve children with impaired glucose tolerance (IGT) had higher UA levels than subjects with normal glucose tolerance (NGT) (5.1 +/- 1.1 v 4.2 +/- 1.2 mg/dL, P <.05), and showed the strongest relation between serum leptin and UA (r =.76, P <.001). Multiple regression analyses demonstrated that gender, estimates of total body adiposity (Fat% and SS), birth weight (BW), gestational age (GA), stimulated glucose and insulin, and serum UA are independently associated with serum leptin concentration in former SGA children with dysglycemia (R(2) =.89, P <.001). A long-term effect of intrauterine growth restriction on body fatness, metabolic syndrome, and serum leptin levels is suggested.     

Insulin sensitivity and secretion are related to catch-up growth in small-for-gestational-age infants at age 1 year: results from a prospective cohort

Strong associations between low birth weight and insulin resistance have been described. However, most of these studies have been retrospective. We aimed to determine whether infants born small for gestational age (SGA: birth weight <5th percentile for gestational age) have decreased insulin sensitivity, compared with appropriate for gestational age (AGA: birth weight >10th percentile) at 1 yr of age. We studied blood lipids, fasting insulin levels, other markers of insulin sensitivity, and insulin secretion during an iv glucose tolerance test in a cohort of 85 SGA and 23 AGA 1-yr-old infants. In addition, SGA infants were stratified according to catch-up growth (CUG) in weight (WCUG) or length (LCUG) during the first year of life. At 1 yr, SGA infants had a clear tendency to higher triglycerides. Fasting insulin was significantly higher in SGA infants with WCUG, compared with those who did not catch up and AGA infants (mean +/- SEM, 32.6 +/- 4.6 vs. 14.9 +/- 2.3 vs. 21.4 +/- 3.3 pM, respectively; P < 0.05). Length increment (in SD score) was the principal determinant of postload insulin secretion (R(2) = 0.1, P < 0.01). We conclude that insulin secretion and sensitivity are closely linked to patterns of rapid WCUG and LCUG during early postnatal life. Fasting insulin sensitivity is more related to WCUG and current body mass index, whereas insulin secretion seems to be directly related to LCUG.     

The tumour necrosis factor (TNF)-alpha-308GA promoter polymorphism is related to prenatal growth and postnatal insulin resistance

OBJECTIVE: Variation in the tumour necrosis factor gene, (TNF) has been associated with insulin resistance traits. We questioned whether the TNF-308G/A polymorphism is associated with birthweight and insulin resistance in children born small for gestational age (SGA), a patient population known to be at risk for insulin resistance. DESIGN: A cross-sectional, hospital-based study assessing insulin sensitivity in SGA children. PATIENTS: One hundred and ninety-eight school-age children born either SGA (n=90, age 7.4+/- 4.5 years) or appropriate for gestational age (AGA, n=108, age 8.7+/- 4.0 years). MEASUREMENTS: All children were genotyped for the TNF-308G/A polymorphism; a biochemical profile was also performed in prepubertal SGA (n=58) and AGA (n=57) subjects. RESULTS: Genotype frequencies for the TNF-308G/A single nucleotide polymorphisms (SNPs) (GG and GA/AA) differed between SGA and AGA children (86%vs. 72% and 14%vs. 28%, respectively; P=0.025). The GG genotype was associated with lower birthweight and birth length (2747.0+/- 23.3 g vs. 2851.0+/- 45.7 g, P=0.045, and 47.0+/- 0.2 cm vs. 48.2+/- 0.4 cm, P=0.011, respectively) and, in AGA but not in SGA children, with higher systolic blood pressure [103.3 (95% confidence interval (CI) 96.4-110.2) mmHg vs. 92.8 (84.9-100.7) mmHg; P=0.028], higher blood glucose [4.8 (4.7-5.0) mmol/l vs. 4.5 (4.3-4.8) mmol/l; P=0.042] and higher homeostasis model assessment for insulin resistance (HOMA-IR) index [1.4 (1.1-1.7) vs. 0.9 (0.4-1.3); P=0.005]. In multivariate analysis, the TNF-308GG genotype was an independent predictor of HOMA-IR during childhood, explaining 8% of its variance. CONCLUSION: SGA children show increased frequency of the TNF-308G allele, an allele that is associated with prenatal growth and with postnatal insulin resistance. The TNF-308G/A polymorphism may have implications in the growth and metabolic abnormalities that characterise SGA children.     

Reduced insulin sensitivity and the presence of cardiovascular risk factors in short prepubertal children born small for gestational age (SGA)

BACKGROUND: Epidemiological studies have shown that the metabolic syndrome, a combination of type 2 diabetes mellitus, hypertension, dyslipidaemia and a high body mass index (BMI), occurs more frequently among adults who were born with a low birth weight. Because insulin is thought to play a key role in the pathogenesis of this syndrome we investigated insulin sensitivity and risk factors for cardiovascular disease in short prepubertal children born small for gestational age (SGA). PATIENTS AND METHODS: Frequently sampled intravenous glucose tolerance tests (FSIGT) were performed in 28 short prepubertal children born SGA. Short stature was defined as a height < -2SD. SGA was defined as a birth length and/or a birth weight for gestational age < -2SD. Twelve short children born appropriate for gestational age (AGA) were used as controls for the FSIGT's results only. AGA was defined as a birth weight and/or birth length for gestational age > -2SD. In short SGA children, blood pressure (BP), fasting levels of serum free fatty acids (FFA), triglycerides (TG), total cholesterol (TC), high-density lipoprotein (HDL) cholesterol and low-density lipoprotein (LDL) were measured and compared to reference values. RESULTS: Mean insulin sensitivity (Si) level in short SGA children was significantly reduced to 38% of the mean Si level measured in short AGA controls (P = 0.004). Mean acute insulin response (AIR) was significantly higher in SGA children compared to short AGA controls (P < 0.001). Differences in Si and AIR between the two groups remained significant after adjusting for age and BMI (P < 0.001 and P = 0.003, respectively). The mean (SD) systolic BP SDS was 1.3 (1,1), being significantly higher than zero. Mean fasting serum levels of FFA, TC, TG, HDL and LDL were all within the normal range. However, 6 of the 28 SGA children had serum FFA levels above the normal range. Cardiovascular risk factors could statistically be represented in two clusters. Both clusters played a significant role in the development of insulin insensitivity (1/Si). CONCLUSION: Although the metabolic syndrome has been described in adulthood, our study showed that risk factors for the development of type 2 diabetes mellitus and cardiovascular disease are already present during childhood in short prepubertal children born SGA, suggesting a pretype 2 diabetes mellitus phenotype.     

Fat mass accumulation during childhood determines insulin sensitivity in early adulthood

BACKGROUND/OBJECTIVES: Low birth weight and postnatal catch-up growth have been associated with an increased risk for diabetes mellitus type II (DMII). We evaluated the contribution of birth and adult size, body composition, and waist-to-hip ratio to DMII risk factors in young adulthood. METHODS: In a group of 136 young adults, aged 18-24 yr, insulin sensitivity and disposition index were determined by frequent sampling iv glucose tolerance test. The association of clinical parameters with these variables was analyzed with multiple regression modeling. In addition, differences in insulin sensitivity and disposition index, a measure for beta-cell function, were analyzed in four subgroups, young adults either born small for gestational age SGA with short stature (n = 25) or SGA with catch-up growth (n = 23) or born appropriate for gestational age with idiopathic short stature (n = 23) or with normal stature (controls) (n = 26). RESULTS: Fat mass was the only significant predictor of insulin sensitivity, whereas birth length and birth weight were not significant. After correction for age, gender, and adult body size, insulin sensitivity was significantly lower in subjects born SGA with catch-up growth compared with controls. None of the variables had a significant influence on disposition index, and there was no significant difference in disposition index between the subgroups. CONCLUSIONS: Our data show that a higher body fat mass at 21 yr is associated with reduced insulin sensitivity, independent of birth size. These findings have important implications for public health practice.     

Adiponectin levels in the first two years of life in a prospective cohort: relations with weight gain, leptin levels and insulin sensitivity

Adiponectin, a novel adipocytokine with insulin sensitizing properties, is inversely related to obesity and insulin resistance in adults. We recently reported large variations in weight gain and insulin sensitivity during the first year in infants born small for gestational age (SGA) or appropriate for gestational age (AGA). We now determined whether adiponectin levels were related to postnatal growth and insulin sensitivity in a prospective cohort followed from birth to two years old (n = 85) (55 female/30 male, 65 SGA/20 AGA). Serum adiponectin levels at one year and two years were higher compared to reported levels in adults and older children, and decreased from one year (21.6 +/- 0.6 microg/ml) to two years (15.7 +/- 0.7 microg/ml) (p < 0.05). At two years adiponectin levels were lower in females (15.3 +/- 0.4 microg/ml) than males (16.4 +/- 0.6 microg/ml) (p < 0.05), but no gender difference was seen in leptin or insulin levels. No differences in adiponectin levels were seen between SGA and AGA infants at one or two years. However, in SGA infants changes in adiponectin between one to two years old were inversely related to weight gain (r = -0.310, p < 0.05). Changes in leptin levels between one to two years were positively related to weight gain in both SGA and AGA infants (r = 0.450 and r = 0.500 respectively, both p < 0.05). Adiponectin levels were unrelated to insulin levels at one or two years, nor to change in insulin levels between one to two years. In multiple regression analysis, adiponectin levels were related only to postnatal age; omitting age from the model, the determinants of higher adiponectin levels were male gender (p = 0.03), lower postnatal body weight (p < 0.001), and higher birth weight SD score (p = 0.004). In conclusion, fall in serum adiponectin levels during the first two years of life were related to increasing age and greater weight gain SGA infants, but were unrelated to insulin sensitivity.     

Effects of the Trp64Arg polymorphism in the beta3-adrenergic receptor gene on insulin sensitivity in small for gestational age neonates

To evaluate whether the Trp64Arg polymorphism in the beta3-adrenergic receptor (AR) gene is associated with decreased birth weight and might account for some of the association between birth weight and impaired insulin sensitivity, the beta3-AR genotype was assessed in 296 neonates of singleton pregnancies, including 76 neonates classified as small for gestational age (SGA) and 220 neonate classified as appropriate for gestational age (AGA). Fasting glucose and insulin levels were measured on d 3 after birth. The insulin levels and insulin-to-glucose ratio were significantly higher in the SGA group than in the AGA group. Frequency of the Trp64Arg allele was similar in the AGA and SGA groups (0.15 and 0.17, respectively). Moreover, when we adjusted for sex and gestational age, there was no significant difference in birth weight, fasting glucose, insulin levels, or insulin-to-glucose ratio between those with and without the mutation. However, in the SGA group, carriers of the Trp64Arg allele had significantly higher fasting insulin levels and insulin-to-glucose ratios than noncarriers (17.54 +/- 2.11 vs. 13.18 +/- 1.47 microIU/ml, P < 0.05; and 4.89 +/- 0.60 vs. 3.14 +/- 0.42, P < 0.05, respectively), whereas no association was detected for this polymorphism in the AGA group.SGA is an important factor that predisposes to insulin resistance, and the Trp64Arg beta3-AR gene polymorphism may contribute to insulin resistance associated with reduced fetal growth.     

Simultaneous evaluation of insulin secretion and action using a model

For the simultaneous evaluation of insulin secretion and insulin sensitivity, a glucose regulation model has been developed. In order to estimate the parameters of the model, an intravenous glucose infusion test (GIT, 100 mg/kg.min x 2 min and 10 mg/kg.min x 118 min) was carried out on 15 healthy subjects (N), 12 subjects with impaired glucose tolerance (IGT), 20 non-insulin-dependent diabetics (NIDDM) and 13 patients with chronic pancreatitis (CP). The coefficient (microU/mg) for insulin secretion depending on blood glucose concentration in IGT, NIDDM and CP were lower (35.9 +/- 2.7, 24.5 +/- 3.3, 43.1 +/- 3.1) than in N (77.5 +/- 7.9). The coefficients (microU.min/mg) for insulin secretion depending on rate of change in blood glucose concentration in IGT and NIDDM were significantly lower (6.5 +/- 2.1, 3.8 +/- 1.2) than in N (52.8 +/- 8.8). The insulin sensitivity index (ISI; 10(-2) mg/(microU/ml).kg.min) in NIDDM was lower (4.98 +/- 0.75) than in N (11.37 +/- 1.08). Administration of exogenous insulin did not significantly affect the value of ISI in N and NIDDM. ISI showed a tendency to increase (15.09 +/- 1.92) in CP. It was demonstrated that the proposed model which estimates both insulin secretory ability and insulin sensitivity simultaneously is quite useful for analyzing the mechanism of impaired glucose tolerance.     

Longitudinal changes in insulin sensitivity and secretion from birth to age three years in small- and appropriate-for-gestational-age children

Aims/hypothesis Insulin resistance and type 2 diabetes risk in human subjects who were small-for-gestational-age (SGA) at birth may be a consequence of rapid early postnatal weight gain. Materials and methods We prospectively studied early changes in fasting insulin sensitivity and insulin secretion, assessed by a short intravenous glucose tolerance test that was conducted several times from birth to 3 years of age in 55 SGA (birthweight below fifth percentile) newborns and in 13 newborns with a birthweight appropriate for gestational age (AGA). Results Most SGA infants showed postnatal upward weight centile crossing and by 3 years were similar in size to AGA infants. SGA infants had lower pre-feed insulin levels at postnatal age 48 h than AGA infants (median 34.4 vs 59.7 pmol/l, p<0.05), but by the age of 3 years they had higher fasting insulin levels (median 38.9 vs 23.8 pmol/l, p<0.005), which were related to rate of weight gain between 0 and 3 years (r=0.47, p=0.0003). First-phase insulin secretion did not differ between SGA and AGA infants, but SGA infants had a lower glucose disposition index (beta cell compensation) (median 235 vs 501 min mmol⁻¹ l⁻¹, p=0.02), which persisted after allowing for postnatal weight gain (p=0.009). Conclusions/interpretation SGA infants showed a marked transition from lower pre-feed insulin and increased insulin sensitivity at birth to insulin resistance over the first 3 years of life. This transition was related to rapid postnatal weight gain, which could indicate a propensity to central fat deposition. The additional observation of reduced compensatory beta cell secretion underlines the need for long-term surveillance of glucose homeostasis in all SGA subjects, whether or not they show postnatal catch-up growth.     

Influence of insulin treatment on insulin sensitivity in insulin requiring type 2 diabetes patients

Insulin resistance in type 2 diabetes subjects was investigated before and 6 months after insulin administration in 43 type 2 diabetes patients (28 females and 15 males). Their age was 56.1+/-8.6 years, diabetes duration 11.7+/-6.8 years, BMI 29.5+/-5.3 kg/m2. All patients were on maximal dosage of oral hypoglycaemic agents and had poor metabolic control (HbA1c 11.2+/-1.6%). Insulin sensitivity was measured by euglycaemic clamp (insulin infusion rate 1 mU kg-1 min-1). The glucose disposal rate (M-value) was considerably lower in patients (2.4+/-1.6 mg kg-1 min-1, 0.2-8.1) compared with healthy subjects (7.1+/-0.2 mg kg-1 min-1, p<0.01). M-value was strongly associated with WHR (r=-0.41, p<0.05). The patients with poorest insulin sensitivity had the highest level of total cholesterol (r=-0.41, p=0.02) and LDL-cholesterol (r=-0.38, p=0.03). After 6 months of insulin treatment BMI was 30.3+/-4.2 kg/m2 (p<0.05), mean weight increase was 2.7+/-0.8 kg. M-value was substantially increased to 4.5+/-2.3 mg kg-1 min-1 (p<0.001), the degree of improvement depended on basal insulin sensitivity (r=-0.55, p<0.01). HbA1c was reduced to 7.7+/-1.4% (p<0.01), the correlation M-value with change of HbA1c (r=-0.59, p<0.01) was shown. Total cholesterol decreased from 6.3+/-1.1 to 5.4+/-1.1 mmol/l, LDL-cholesterol from 4.1+/-1.1 to 3.4+/-1.0 mmol/l, triglycerides from 2.6+/-1.6 to 1.6+/-0.7 mmol/l (p<0.001). In conclusion, insulin treatment of type 2 diabetes patients leads to decrease in insulin resistance due to reduction in glucose toxicity and plasma atherogenicity despite weight gain.     

Phenotypic characteristics according to insulin sensitivity in non-obese Korean women with polycystic ovary syndrome

Over 50% of women with polycystic ovary syndrome (PCOS) have been reported to have varying degree of insulin resistance and it may contribute to hyperandrogenism. The aim of the study is to identify whether the insulin resistance is present in non-obese Korean women with PCOS and whether the phenotype is different according to insulin sensitivity. Seventy-three non-obese (BMI<23 kg/m(2)) women with PCOS and 34 age and BMI comparable control women with regular menstrual cycles were examined. Standard 75 g OGTT was performed to determine the status of glucose tolerance. Insulin sensitivity was measured by euglycemic hyperinsulinemic clamp technique. The fasting plasma glucose (p<0.01) and post-glucose load plasma insulin (p<0.01) of women with PCOS were higher than those of controls. Glucose disposal rate (M-value) was lower in women with PCOS compared to controls (p<0.05). Insulin resistant (IR) and insulin sensitive (IS) PCOS were divided by the M-value of 25-percentile (5.5mg/kg min) in controls. Between IR and IS groups, DHEAS (p<0.01), post-glucose load plasma insulin (p<0.05) showed differences after the adjustment for BMI. Our non-obese women with PCOS showed significant insulin resistance compared to their age and BMI comparable control subjects and their insulin resistance may contribute to hyperandrogenism especially via adrenal androgen overproduction.     

Increased oxidative stress in prepubertal children born small for gestational age

CONTEXT: Low birth weight is associated with an increased risk of metabolic and cardiovascular diseases in adulthood. The development of insulin resistance (IR) seems to play a pivotal role; no data on the oxidant-antioxidant status are available in this risk group. OBJECTIVE: This study is an assessment of oxidant-antioxidant status in prepubertal children born small for gestational age (SGA) in comparison to healthy controls and the relationship to IR. DESIGN: This cross-sectional study compares indexes of IR and oxidant-antioxidant status in three different groups (SGA+, SGA-, controls), with analysis by post hoc and Pearson correlation. SETTING: The study was conducted in the Academic Department of Pediatrics. PARTICIPANTS: A total of 19 SGA+ and 16 SGA- children were compared with 13 controls. INTERVENTION: No intervention was used. MAIN OUTCOME MEASURES: Indexes of IR (glucose to insulin ratio, homeostasis model assessment of IR) were evaluated, and markers of oxidative stress (lag phase, malonildialdehyde, vitamin E) were measured. RESULTS: Homeostasis model assessment of IR was significantly higher in SGA+ than SGA- children (1.32+/-0.9 vs. 0.69+/-0.47; P=0.03) and controls (0.71+/-0.37; P=0.04). Glucose to insulin ratio was significantly lower in SGA+ than SGA- children (12.41+/-5.01 vs. 26.54+/-17.18; P=0.02) and controls (26.96+/-20.70; P=0.04). Lag phase was significantly shorter in SGA+ than SGA- children (24.3+/-4.38 vs. 35.59+/-11.29 min; P=0.003) and controls (45.28+/-7.69 min; P=0.0001) and in SGA- than controls (P=0.01). Malonildialdehyde was significantly higher in SGA+ than SGA- children (0.79+/-0.3 vs. 0.6+/-0.1 nmol/mg; P=0.03) and controls (0.36+/-0.04 nmol/mg; P=0.0001) and in SGA- children than controls (P=0.02). Vitamin E was significantly reduced in SGA+ children than controls (27.54+/-7.9 vs. 43.23+/-11.32 micromol/liter; P=0.002). CONCLUSION: Oxidative stress is present in both SGA+ and SGA- children, with a continuous alteration in relation to IR. Therefore, catch-up growth might exert the greatest influence in the development of future diseases.     

How insulin resistant are patients with noninsulin-dependent diabetes mellitus?

The study was carried out to quantify the ability of physiological increases in the plasma insulin concentration to stimulate glucose disposal above basal levels in 25 normal subjects and 25 patients with noninsulin-dependent diabetes mellitus (NIDDM). Patients were sex, age, and weight matched, and glucose disposal was determined under basal conditions (plasma insulin, approximately 10 microU/ml) and after plasma insulin levels had been increased to approximately 90 microU/ml. The mean (+/- SEM) glucose disposal rate was significantly greater (P less than 0.001) under basal conditions in patients with NIDDM (110 +/- 5 mg/m2 X min) than in individuals with normal glucose tolerance (77 +/- 4 mg/m2 X min). Glucose disposal rates increased in both normal subjects and NIDDM patients when plasma insulin concentrations were increased to about 90 microU/ml; however, the increment was much greater in normal subjects. Thus, glucose disposal only rose to a mean (+/- SEM) value of 145 +/- 7 mg/m2 X min in patients with NIDDM, representing an approximate 30% increase due to insulin. In contrast, a similar elevation of plasma insulin in normal subjects resulted in an increase in glucose disposal of approximately 300%, reaching a mean (+/- SEM) value of 310 +/- 24 mg/m2 X min. These results indicate that the defect in insulin-stimulated glucose uptake is significantly greater in patients with NIDDM than has previously been found.