Serum insulin-like growth factor binding protein-1 at 16 weeks and subsequent preeclampsia

OBJECTIVE: To determine whether serum concentrations of insulin-like growth factor-binding protein-1 (IGFBP-1), a major decidual protein, at 16 weeks' gestation differ between women who later develop pregnancy-related hypertension and normotensive women. METHODS: Concentrations of IGFBP-1 were measured using immunoenzymometric assay in serum samples collected for alpha-fetoprotein (AFP) and free beta subunit of hCG (free beta-hCG) determinations in a Down syndrome screening program at 16 weeks' gestation in a population-based cohort of 1049 nulliparous women. After exclusion of subjects with multiple pregnancies, insulin-dependent diabetes, major fetal malformations, and incomplete data, 917 subjects remained eligible. RESULTS: The mean levels (+/- standard deviation) of IGFBP-1 were significantly lower in 34 women who later developed preeclampsia (73 +/- 43 microg/L, P < .01) and in 80 women with White A diabetes (84.7 +/- 53 microg/L, P < .01) compared with controls (103 +/- 58 microg/L). In seven women with White A diabetes and subsequent preeclampsia IGFBP-1 levels were especially low (41 +/- 34 microg/L). The concentrations of AFP and free beta-hCG in the subgroups with hypertensive disorders were not significantly different from those of normotensive women. CONCLUSION: Decreased IGFBP-1 levels at 16 weeks' gestation in women who develop preeclampsia might indicate impaired decidual function. Hyperinsulinemia, a known risk factor for preeclampsia, might contribute to decreased concentrations of serum IGFBP-1. However, due to low sensitivity, assay of serum IGFBP-1 was not clinically valuable for predicting preeclampsia.     

Serum levels of leptin,insulin-like growth factor-I and insulin-like growth factor binding protein-3 in women with pre-eclampsia,and their relationship to insulin resistance

The present study was carried out to compare serum levels of leptin, insulin-like growth factor-I (IGF-I), insulin-like growth factor binding protein-3 (IGFBP-3), homeostasis model assessment–(pancreatic β-cell function) (HOMA-(%B)) and homeostasis model assessment–(tissue insulin sensitivity) (HOMA-(%S)) in women with mild and severe pre-eclampsia and normotensive pregnant women; and to evaluate the possible relationships between these parameters in the pathogenesis of pre-eclampsia. Seventy-three women were divided into three groups: group A consisted of 20 normotensive pregnant women (NPW); group B consisted of 25 women with mild pre-eclampsia (MPE); and group C consisted of 28 women with severe pre-eclampsia (SPE). Serum level of leptin was measured by enzyme immunoassay using a commercial kit. Serum levels of IGF-I and IGFBP-3 were measured with a two-site immunoradiometric assay. Serum level of insulin was measured by the electrochemiluminescence immunoassay method. HOMA used indices of pancreatic β-cell function and tissue insulin sensitivity. Differences between groups were compared by one-way analyses of variance and the post hoc Tukey–HSD test for multiple comparisons; however, when a variable was not normally distributed, the Mann–Whitney U test was used. Associations between variables were tested using Pearson's coefficient of correlation. Birth weight was significantly lower (p?<?0.001) in the MPE and SPE groups than in the NPW group. Serum levels of leptin and insulin in women with SPE and MPE were significantly higher (p?<?0.001) than in NPW. Serum levels of IGF-I and IGFBP-3 were significantly lower in women with SPE and MPE compared with NPW (p?<?0.001). The mean HOMA-(%B) level in women with SPE and MPE was significantly higher than in NPW (p?<?0.001), whereas the mean HOMA-(%S) level in women with SPE and MPE was significantly lower than in NPW (p?<?0.001). In the SPE group, systolic blood pressure correlated significantly with serum levels of IGF-I and leptin (r?=?0.375, p?<?0.05 and r?= 0.495, p?<?0.01, respectively). A negative correlation between mean HOMA-(%S) level and serum IGFBP-3 level was noted (r?=?–0.357, p?<?0.05). There was a positive correlation between serum level of IGF-I and mean HOMA-(%B) level in mildly pre-eclamptic women (r?=?0.541, p?<?0.01). We conclude that pre-eclampsia is associated with insulin resistance; and that existing hyperinsulinemia and insulin resistance in women with pre-eclampsia seem not to correlate with leptin and birth weight, but may correlate positively with IGF-1 and IGFBP-3. Therefore we think that hyperleptinemia, low IGF-I or IGFBP-3, and insulin resistance may contribute to the pathogenesis of pre-eclampsia.     

Serum levels of leptin, insulin-like growth factor-I and insulin-like growth factor binding protein-3 in women with pre-eclampsia, and their relationship to insulin resistance.

The present study was carried out to compare serum levels of leptin, insulin-like growth factor-I (IGF-I), insulin-like growth factor binding protein-3 (IGFBP-3), homeostasis model assessment--(pancreatic beta-cell function) (HOMA-(%B)) and homeostasis model assessment--(tissue insulin sensitivity) (HOMA-(%S)) in women with mild and severe pre-eclampsia and normotensive pregnant women; and to evaluate the possible relationships between these parameters in the pathogenesis of pre-eclampsia. Seventy-three women were divided into three groups: group A consisted of 20 normotensive pregnant women (NPW); group B consisted of 25 women with mild pre-eclampsia (MPE); and group C consisted of 28 women with severe pre-eclampsia (SPE). Serum level of leptin was measured by enzyme immunoassay using a commercial kit. Serum levels of IGF-I and IGFBP-3 were measured with a two-site immunoradiometric assay. Serum level of insulin was measured by the electrochemiluminescence immunoassay method. HOMA used indices of pancreatic beta-cell function and tissue insulin sensitivity. Differences between groups were compared by one-way analyses of variance and the post hoc Tukey-HSD test for multiple comparisons; however, when a variable was not normally distributed, the Mann-Whitney U test was used. Associations between variables were tested using Pearson's coefficient of correlation. Birth weight was significantly lower (p < 0.001) in the MPE and SPE groups than in the NPW group. Serum levels of leptin and insulin in women with SPE and MPE were significantly higher (p < 0.001) than in NPW. Serum levels of IGF-I and IGFBP-3 were significantly lower in women with SPE and MPE compared with NPW (p < 0.001). The mean HOMA-(%B) level in women with SPE and MPE was significantly higher than in NPW (p < 0.001), whereas the mean HOMA-(%S) level in women with SPE and MPE was significantly lower than in NPW (p < 0.001). In the SPE group, systolic blood pressure correlated significantly with serum levels of IGF-I and leptin (r = 0.375, p < 0.05 and r = 0.495, p < 0.01, respectively). A negative correlation between mean HOMA-(%S) level and serum IGFBP-3 level was noted (r = -0.357, p < 0.05). There was a positive correlation between serum level of IGF-I and mean HOMA-(%B) level in mildly pre-eclamptic women (r = 0.541, p < 0.01). We conclude that pre-eclampsia is associated with insulin resistance; and that existing hyperinsulinemia and insulin resistance in women with pre-eclampsia seem not to correlate with leptin and birth weight, but may correlate positively with IGF-1 and IGFBP-3. Therefore we think that hyperleptinemia, low IGF-I or IGFBP-3, and insulin resistance may contribute to the pathogenesis of pre-eclampsia.     

Serum insulin-like growth factor-I and insulin-like growth factor binding protein-3 in premature rupture of membranes

BACKGROUND: The aim of the study was to evaluate whether the circulating levels of insulin-like growth factor-I (IGF-I) and its major circulating binding protein, IGFBP-3, are affected in premature rupture of membranes (PROM) and preterm delivery. METHODS: The levels of IGF-I and IGFBP-3 were measured in 32 pregnant women with PROM and in 27 healthy gestational age-matched pregnant women. Statistical analyzes were performed by analysis of variance. RESULTS: All the patients with PROM had preterm delivery, at a gestational age of 31.9 +/- 0.4 weeks (mean +/- SEM). In the control subjects, pregnancy proceeded to term. In the PROM patients, the serum IGF-I and IGFBP-3 levels (289 +/- 21 ng/ml and 8248 +/- 407 ng/ml, respectively) were not statistically different from those in the control subjects (275 +/- 22 ng/ml and 7579 +/- 488 ng/ml). Seventeen patients with PROM showed a rise in serum C-reactive protein, indicating subclinical intrauterine infection. Also in this subgroup of patients the levels of serum IGF-I (281 +/- 27 ng/ml) and IGFBP-3 (9010 +/- 633 ng/ml) were not different from those in the control subjects. Before delivery, serial serum samples were available from 22 patients with PROM. No consistent changes in IGF-I or IGFBP-3 concentrations were seen during the mean follow-up period of 9 days. CONCLUSIONS: IGF-I and IGFBP-3 do not appear to play any significant role in the maintenance of pregnancy in PROM patients with preterm delivery, whether or not associated with emerging intrauterine infection.     

Regulation of insulin-like growth factor-I and insulin-like growth factor binding protein-1 concentrations in preterm fetuses

OBJECTIVE: Our purpose was to evaluate which factors regulate insulin-like growth factor-I and insulin-like growth factor binding protein-1 concentrations in preterm fetuses. STUDY DESIGN: We studied 76 singleton births between 25 and 36 weeks of gestation. Forty-nine pregnancies were complicated by hypertensive disease; 24 pregnancies were complicated by preterm labor or preterm rupture of membranes; and antenatal glucocorticoids were given in 49 pregnancies. Pathology reports showed infarct(s) or hematoma(s) in 31 of 69 placentas. We recorded blood gas values in umbilical artery and vein and measured glucose, C-peptide, and insulin-like growth factor-I and insulin-like growth factor binding protein-1 concentrations in umbilical vein. RESULTS: Birth weight correlated with umbilical vein insulin-like growth factor-I (r = 0.68, P <.0001) and inversely with insulin-like growth factor binding protein-1 (r = -0.26, P =.02). Babies with birth weight of 25th percentile. Two-factor analysis of variance showed that umbilical vein insulin-like growth factor-I was determined by gestational age (P =.0004) and birth weight percentile (P <.0001), whereas insulin-like growth factor binding protein-1 was not affected by gestational age. Umbilical vein C-peptide was highly correlated with insulin-like growth factor binding protein-1 (r = -0.55, P <.0001), but not insulin-like growth factor-I, levels. Blood gas values in umbilical artery and vein, particularly umbilical artery PO (2), were correlated with umbilical vein insulin-like growth factor-I and insulin-like growth factor binding protein-1 (r = 0.51 and -0.48, respectively; P <.0001); changes in insulin-like growth factor-I and insulin-like growth factor binding protein-1 occurred at umbilical artery PO (2) <14.8 mm Hg. Multiple regression analysis showed that umbilical vein insulin-like growth factor-I was predicted by umbilical artery PO (2), gestational age, and the presence of placental infarcts/hematomas (R (2) of model = 0.58, P <.0001), and umbilical vein insulin-like growth factor binding protein-1 by umbilical vein C-peptide, umbilical artery PO (2), and placental infarcts/hematomas (R (2) = 0.49, P <.0001). CONCLUSION: In the preterm fetus, circulating insulin-like growth factor-I is related to gestational age and the in utero growth potential, whereas insulin-like growth factor binding protein-1 is related only to the in utero growth potential. The PO (2) is a robust determinant of both insulin-like growth factor-I and insulin-like growth factor binding protein-1 levels; hypoxia may restrain fetal growth through its effects on the insulin-like growth factor/insulin-like growth factor binding protein axis. Insulin is a powerful determinant of insulin-like growth factor binding protein-1, but not insulin-like growth factor-I, concentrations in the preterm fetus.     

Longitudinal analysis of serum insulin-like growth factor-I and insulin-like growth factor binding protein-1 in antiphospholipid syndrome and in healthy pregnancy

OBJECTIVE: The purpose of this study was to determine the concentrations of serum insulin-like growth factor-I and insulin-like growth factor binding protein-1 in pregnancies that are complicated with primary antiphospholipid syndrome. STUDY DESIGN: Longitudinal blood samples were collected from 8 weeks of gestation in 28 women with treated primary antiphospholipid syndrome and 19 control women. Serum insulin-like growth factor-I and insulin-like growth factor binding protein-1 were measured by immunoradiometric assay. RESULTS: Three antiphospholipid syndrome pregnancies miscarried, four pregnancies had intrauterine growth restriction and preeclampsia, six pregnancies had a thrombotic event, and one pregnancy had abruptio placentae. Mean (+/-SD) birth weight in antiphospholipid syndrome group was 2867 +/- 914 g (control, 3492 +/- 527 g; P =.02), and the mean gestation at delivery was 36.5 +/- 5.2 weeks (control, 40.3 +/- 0.7 weeks; P =.002). Insulin-like growth factor binding protein-1 and insulin-like growth factor-I concentrations increased with gestational age in both groups (2.8% and 2.4% per week), but insulin-like growth factor binding protein-1 was 61% higher in the antiphospholipid syndrome group (95% CI, 16%-122%; P =.004). Insulin-like growth factor-I was not significantly different (8% higher in antiphospholipid syndrome; 95% CI, -10% to 30%; P =.41). CONCLUSION: Serum concentrations of insulin-like growth factor binding protein-1 are abnormal in the antiphospholipid syndrome group and may reflect abnormalities in trophoblast invasion.     

The relationship between insulin and insulin-like growth factor binding protein-1 is modified by pre-eclampsia

Insulin is the main negative regulator of insulin-like growth factor binding protein-1 (IGFBP-1) in the non-pregnant state. Although changes in insulin resistance and circulating level of IGFBP-1 occur in pre-eclampsia, little is known about the relationship between insulin and IGFBP-1 in pregnancies complicated by the disease. In this study, we have investigated whether the relationship between insulin and IGFBP-1 is modified by pre-eclampsia. Maternal levels of insulin and IGFBP-1 were measured, at 4-weekly intervals between 16 and 36 weeks' gestation, in plasma samples obtained from ten normal pregnant controls and ten women who developed pre-eclampsia. The controls were chosen to be similar in maternal age and booking body mass index to the pre-eclampsia group. Insulin levels increased in both the normal controls and the women who developed pre-eclampsia. The levels in pre-eclampsia were significantly greater than those in normal pregnancy at 32 and 36 weeks' gestation (p?=?0.02 and 0.005, respectively). IGFBP-1 levels were unchanged in normal pregnancy and rose in pre-eclampsia. In normal pregnancy, insulin levels were inversely related to IGFBP-1 levels throughout. In women developing pre-eclampsia, the relationship between insulin and IGFBP-1 was negative at 16 weeks and positive from 24 weeks. These data suggest that whereas the inverse relationship between insulin and IGFBP-1 is maintained during normal pregnancy, this relationship is reversed in women who develop pre-eclampsia.     

Relationship of insulin-like growth factor-I and insulin-like growth factor binding proteins in umbilical cord plasma to preeclampsia and infant birth weight.

OBJECTIVE: To determine whether preeclampsia influences insulin-like growth factor-I (IGF-I), insulin-like growth factor binding protein-1 (IGFBP-1), and insulin-like growth factor binding protein-3 (IGFBP-3), independent of its effect on birth weight. METHODS: Cord blood was collected in 12,804 consecutive deliveries. We identified 258 preeclamptic pregnancies that were subclassified as mild or severe and early or late. For comparison, 609 control pregnancies were selected. Fetal growth was expressed as the ratio between observed and expected birth weight, with adjustment for gestational age at birth. IGF-I, IGFBP-1, and IGFBP-3 were measured in umbilical plasma. The contribution of preeclampsia and birth weight to each measured factor was assessed by multiple linear regression analyses. RESULTS: Between mild preeclampsia and controls, there were no differences in IGF-I, IGFBP-1, and IGFBP-3. In severe and early onset preeclampsia, umbilical cord plasma IGF-I was approximately 50% lower, and IGFBP-1 was more than twice as high as in controls (both P <.01). At each birth weight level, IGF-I was lower and IGFBP-1 was higher in severe or early preeclampsia than among controls of similar weight. Birth weight and preeclampsia were, independent of each other, associated with IGF-I, whereas birth weight, but not preeclampsia, was associated with IGFBP-1, after adjustment for gestational age. CONCLUSION: Fetal growth restriction caused by severe or early preeclampsia is associated with lower umbilical levels of IGF-I than low birth weight caused by other conditions. Preeclampsia may contribute to the observed IGF-I reduction, either as part of the underlying causes of preeclampsia, or as a consequence of the disease.     

The relationship between insulin and insulin-like growth factor binding protein-1 is modified by pre-eclampsia.

Insulin is the main negative regulator of insulin-like growth factor binding protein-1 (IGFBP-1) in the non-pregnant state. Although changes in insulin resistance and circulating level of IGFBP-1 occur in pre-eclampsia, little is known about the relationship between insulin and IGFBP-1 in pregnancies complicated by the disease. In this study, we have investigated whether the relationship between insulin and IGFBP-1 is modified by pre-eclampsia. Maternal levels of insulin and IGFBP-1 were measured, at 4-weekly intervals between 16 and 36 weeks' gestation, in plasma samples obtained from ten normal pregnant controls and ten women who developed pre-eclampsia. The controls were chosen to be similar in maternal age and booking body mass index to the pre-eclampsia group. Insulin levels increased in both the normal controls and the women who developed pre-eclampsia. The levels in pre-eclampsia were significantly greater than those in normal pregnancy at 32 and 36 weeks' gestation (p = 0.02 and 0.005, respectively). IGFBP-1 levels were unchanged in normal pregnancy and rose in pre-eclampsia. In normal pregnancy, insulin levels were inversely related to IGFBP-1 levels throughout. In women developing pre-eclampsia, the relationship between insulin and IGFBP-1 was negative at 16 weeks and positive from 24 weeks. These data suggest that whereas the inverse relationship between insulin and IGFBP-1 is maintained during normal pregnancy, this relationship is reversed in women who develop pre-eclampsia.     

Metformin therapy increases insulin-like growth factor binding protein-1 in hyperinsulinemic women with polycystic ovary syndrome

OBJECTIVES: Polycystic ovary syndrome (PCOS) is associated with hyperandrogenism, insulin resistance, compensatory hyperinsulinemia, and increased levels of free insulin-like growth factor-I (IGF-I), presumably due to a decline in IGF binding protein 1 (IGFBP-1). This study was designed to evaluate effects of metformin therapy on serum levels of IGFBP-1 and IGF-I. STUDY DESIGN: Twenty-seven obese, hyperandrogenic PCOS women with elevated fasting insulin were treated for 12 weeks with metformin (500 mg p.o., t.i.d.). Serum levels of insulin, testosterone, sex hormone binding globulin (SHBG), IGF-I, and IGFBP-1 were measured before and after treatment. Body mass index (BMI) and waist-to-hip ratio (WHR) were assessed at baseline and at the end of therapy. RESULTS: Metformin therapy significantly increased IGFBP-1 concentration by 38% (P = 0.05) but had no demonstrable effect on the total IGF-I levels. Fasting insulin levels declined by 38% (P = 0.0001) while the glucose/insulin ratio increased by 72% (P = 0.0001) and quantitative insulin sensitivity check index (QUICKI) increased by 8% (P = 0.0001). Metformin treatment also significantly decreased testosterone (by 37%, P = 0.0001) and increased SHBG concentration (by 16%, P = 0.04). Multiple linear regression analysis revealed that baseline IGFBP-1 levels correlated inversely and independently with two baseline parameters: WHR (P = 0.003) and free testosterone index (P = 0.04). CONCLUSIONS: The present study shows that metformin therapy not only restores normal levels of insulin and testosterone, but also decreases the pool of free-bioactive IGF-I by increasing the levels of circulating IGFBP-1. We provide further arguments in favor of metformin therapy in hyperinsulinemic women with PCOS.     

Serum levels and molecular sizes of growth hormone during pregnancy in relation to levels of lactogens, insulin-like growth factor I and insulin-like growth factor binding protein-1.

Growth hormone (GH), placental lactogen (PL), prolactin (PRL), insulin-like growth factor I (IGF-I) and IGF binding protein-1 (IGFBP-1) were determined in serum by radioimmunoassays (RIAs) in 12 women during pregnancy. GH and PL were analyzed by two monoclonal antibodies (Mab 3 and Mab 1) raised against pituitary GH. Serum IGFBP-1 had reached maximum levels at midpregnancy while PRL, PL and IGF-I increased continuously during pregnancy. Mab 1, which cross-reacts with PL, measured consistently higher levels of PL in serum than a commercial PL RIA (p less than 0.01) due to interference of cross-reacting serum proteins in the Mab 1 RIA. The GH-specific Mab 3 showed decreasing GH levels in unfractionated serum throughout gestation, but detected GH-immunoreactive proteins of approximately 40-200 kD after molecular sieve chromatography of pooled serum from late pregnancy. It is suggested that the formation of GH complexes of large molecular mass account for the successive disappearance of monomeric GH during pregnancy.     

Oral contraceptives increase insulin-like growth factor binding protein-1 concentration in women with polycystic ovarian disease.

Insulin-like growth factor-I (IGF-I) stimulates ovarian androgen production. Insulin-like growth factor binding protein-1 (IGFBP-1) inhibits IGF actions in vitro. OBJECTIVE: To investigate the effect of oral contraceptive (OC) pills, given for 3 months, on serum gonadotropin, androgen, IGF-I, and IGFBP-1 concentrations, and glucose tolerance in seven women with polycystic ovarian disease (PCOD) and in five healthy control subjects. PATIENTS: Seven women with PCOD and five healthy control subjects. INTERVENTIONS: An oral glucose tolerance test (OGTT) was performed before and after treatment with OC. RESULTS: After treatment with OC, serum luteinizing hormone, androstenedione, and free testosterone levels decreased, and sex hormone-binding globulin concentration increased in the women with PCOD as well as in the control subjects. The cumulative response of serum insulin to OGTT was larger in the women with PCOD than in the control subjects both before and after treatment. Serum IGF-I concentration, which was unchanged during OGTT, decreased from basal level of 326 +/- 70 micrograms/L to 199 +/- 28 micrograms/L after treatment with OC in the women with PCOD, whereas no change was found in the control subjects (from 235 +/- 11 micrograms/L to 226 +/- 11 micrograms/L). Treatment with OC caused an increase of the mean basal IGFBP-1 concentration from 24 +/- 7 micrograms/L to 73 +/- 14 micrograms/L in the women with PCOD. This increase was constant during the OGTT. In the control subjects, treatment with OC did not result in any significant change in IGFBP-1 concentrations (from 44 +/- 11 micrograms/L to 61 +/- 9 micrograms/L). CONCLUSION: The combination of decreased total IGF-I concentration and increased IGFBP-1 concentration induced by OC may decrease ovarian androgen production in PCOD.     

胰岛素样生长因子-Ⅱ和胰岛素样生长因子结合蛋白-1对妊娠早期胚胎发育的影响

目的 探讨胰岛素样生长因子-Ⅱ（insulin-like growth factorⅡ，IGF-Ⅱ）与胰岛素样生长因子结合蛋白1（insulin-like growth factor binding protein-1，IGFBP-1）在妊娠早期对胚胎发育的影响。方法 应用逆转录聚合酶链反应（RT—PCR）、酶联免疫吸附试验（ELISA）分别检测2002-04—2004-01中山大学附属一院47例早孕空胚妊娠妇女（观察组）和38例正常早孕人流妇女（对照组）绒毛组织中的IGF-Ⅱ、蜕膜组织IGFBP-1的mRNA表达量，及母血清中IGFBP-1水平，比较两组数值的相关性。结果 观察组蜕膜组织IGFBP．1mRNA为（3．30±0．32）mg／L，绒毛组织IGF-Ⅱ mRNA为（1．50±0．41）mg／L，母血清IGFBP-1为（50．87±12．08）μg／L；对照组蜕膜组织IGFBP-1 mRNA为（2．14±0．21）mg／L，绒毛组织IGF-Ⅱ mRNA为（3．80±0．17）mg／L，母血清IGFBP-1为（24．31±3．61）μg／L。观察组与对照组间IGF-Ⅱ mRNA、IGFBP-1 mRNA及母血清IGFBP-1比较差异有统计学意义（P〈0．05）；绒毛组织中IGF-Ⅱ mRNA与蜕膜组织中IGFBP-1 mRNA的表达量呈负相关，蜕膜组织IGFBP-1 mRNA与母血清IGFBP-1呈正相关：结论 IGF-Ⅱ、IGFBP-1可能可以作为早期胚胎发育预测潜能的指标，     

Maternal serum insulin-like growth factor binding protein-1 in pregnancy at high altitude

OBJECTIVE: To investigate the effect of environmental hypoxia at 4300-m altitude on the maternal serum concentration of insulin-like growth factor binding protein-1 (IGFBP-1). METHODS: We conducted a cross-sectional study of 108 pregnant women in Peru, 62 from high altitude (4300 m, 14100 ft) and 46 from sea level at 14-42 weeks' gestation. For comparison, 20 healthy nonpregnant women (ten from high altitude and ten from sea level) were also examined. Total and nonphosphorylated IGFBP-1 were measured in maternal serum. RESULTS: Both total and nonphosphorylated IGFBP-1 were higher at high altitude than at sea level in the pregnant groups (ratio = 1.28, P =.008, and ratio = 1.45, P =.003, respectively), and there was significant interaction between high altitude and sea level (P =.037 and P =.043, respectively). The threshold model showed that the difference became significant from 25 weeks' gestation onwards. CONCLUSION: Before 25 weeks of pregnancy, there was no significant difference in IGFBP-1 between women living at high or low altitude, suggesting that the increased IGFBP-1 at high altitude is unlikely to be related to inadequate trophoblast invasion resulting in placental hypoxia. In the second half of pregnancy, the maternal and fetal demands increase dramatically, and low atmospheric oxygen with resulting maternal systemic hypoxemic hypoxia may cause placental hypoxia. This stimulates increased production of IGFBP-1, which in turn restricts the insulin-like growth factor-mediated fetal growth as an adaptive mechanism to prevent worsening of the fetoplacental hypoxia.     

Cervical phosphorylated insulin-like growth factor binding protein-1 in prediction of preterm delivery

Background  The aim of this study was to evaluate the phosphorylated isoform of insulin-like growth factor binding protein-1 (phIGFBP-1) in endocervical secretions as a predictor of preterm delivery in symptomatic and asymptomatic pregnant women. Methods  The study included 105 patients between 24 and 34 weeks’ gestation with uterine contractions and 73 controls. Ph IGFBP-1 in cervical secretions was assessed in all patients by using a qualitative, immunochromatographic one-step dipstick test. Data analysis included Student’s test, Chi-Square, Fisher’s exact test and Kruskal Wallis variance analysis. Results  Preterm birth rate was 19.04% (20/105) in the study group. Of the 25 patients with a positive phIGFBP-1 test, mean gestational age at delivery was 32.8 ± 3.8, whereas of the 80 patients with a negative phIGFBP-1 test mean gestational age at delivery was 37.8 ± 2.5, in the study group (P < 0.05). The sensitivity, specificity, positive predictive value and negative predictive value for phIGFBP-1 in symptomatic patients were 70, 87.05, 56 and 92.5%, respectively, while in asymptomatic patients they were 40, 82.35, 14.28 and 94.91%, respectively. Conclusions  The phIGFBP-1 in cervical secretions is a potential specific marker for preterm delivery occurring before 37 weeks. Also cervical detection of phIGFBP-1 by immunochromotography is a rapid and easily applicable test that highly predicts preterm delivery.     

Maternal zinc and cord blood zinc, insulin-like growth factor-1, and insulin-like growth factor binding protein-3 levels in small-for-gestational-age newborns

PURPOSE: To determine the relationship between maternal serum zinc (Zn) levels and birth weight of the offspring and their correlation with cord blood Zn, insulin-like growth factor (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) levels. METHOD: 22 term small-for-gestational-age (SGA) and 34 term appropriate-for-gestational-age (AGA) infants and their mothers were included. Maternal and cord blood Zn levels and cord blood IGF-1 and IGFBP-3 levels were measured. RESULTS: Eighteen percent of mothers had Zn deficiency (< 75 mcg/dl). No significant difference between IGF-1 and IGFBP-3 levels and birth weight of infants of the mothers with and without Zn deficiency was found. Maternal and neonatal Zn levels correlated (r = 0.38, p < 0.01). Mean IGF-1 and IGFBP-3 levels were significantly lower in the SGA group compared to the AGA group (42.3 +/- 16.8 ng/ml, 1.2 +/- 0.2 mcg/ml, and 62.4 +/- 22.7 ng/ml, 1.5 +/- 0.4 mcg/ml, p < 0.001). A correlation was found between birth weight, IGF-1 and IGFBP-3 levels, and weight gain of the mother during pregnancy (p < 0.01). CONCLUSIONS: Zn deficiency was not observed to be a risk factor for low birth weight. The significant difference between the SGA and AGA babies' IGF-1 and IGFBP-3 levels emphasizes function of the IGF system in intrauterine growth.     

The regional expression of insulin-like growth factor II (IGF-II) and insulin-like growth factor binding protein-1 (IGFBP-1) in the placentae of women with pre-eclampsia

Insulin-like growth factors and their binding proteins regulate cellular proliferation, differentiation and function, and play an important role in placental development. IGF-II and IGFBP-1 are abundantly expressed by cells at the maternal-fetal interface and mediate cell-to-cell communication between trophoblasts and decidua. Placentae of pre-eclamptic pregnancies show villous cytotrophoblast proliferation, increased syncytial sprout formation and impaired trophoblast invasion. We hypothesized that the expression of IGF-II and IGFBP-1 by cells at the maternal-fetal interface is altered in pre-eclampsia. We determined the regional abundance and cellular localization of IGF-II mRNA and IGFBP-1 mRNA and protein in placentae from normotensive control and pre-eclamptic pregnancies. IGF-II mRNA was expressed in both the chorionic villi and basal plate decidua regions. Increased IGF-II mRNA abundance was observed in the intermediate trophoblasts of peri-infarct regions. IGFBP-1 expression was present only in the decidua of the basal plate and membranes, and this expression was decreased significantly in pre-eclamptic placentae. The increased IGF-II expression in the intermediate trophoblast surrounding placental infarcts suggests a role for IGF-II in placental repair or remodelling. Decreased IGFBP-1 mRNA expression in the basal plate decidua suggests that the increased concentrations of IGFBP-1 the circulation of pre-eclamptic women is not of decidual origin. The altered IGF-II and IGFBP-1 expression at the fetomaternal interface may be important in the pathophysiology of pre-eclampsia.     

Role of visfatin, insulin-like growth factor-I and insulin in fetal growth

OBJECTIVE: IGF-I and insulin are the main regulators of intrauterine and postnatal growth. Adipose tissue secreted cytokines are implicated in intrauterine growth. The relevant function of the adipocytokine visfatin is unknown. MATERIALS AND METHODS: Serum visfatin, IGF-I and insulin levels were measured by enzyme immunoassays in 40 singleton full-term fetuses and neonates on postnatal days 1(N1) and 4 (N4). RESULTS: No significant correlations exist between visfatin and IGF-I or insulin. N1 and N4 visfatin positively correlated with customized (adjusted) birth weight centiles (r=0.511, P=0.021, and r=0.597, P=0.005, respectively). Fetal and N1 IGF-I positively correlated with customized centiles (r=0.608, P<0.001 and r=0.485, P=0.006, respectively). Fetal insulin positively correlated with customized centiles (r=0.654, P=0.021). CONCLUSIONS: Potential implication of visfatin in fetal growth is probably not mediated by IGF-I or insulin. Although a more active role cannot be excluded, visfatin may simply represent a marker of fat accumulation.