Maternal and cord blood levels of insulin-like growth factors--I and--II and insulin-like growth factor binding protein-1: correlation with birth weight and maternal anthropometric indices

OBJECTIVES

To study the correlation of maternal and cord blood insulin like growth factor (IGF)-I and -II and IGF binding protein (IGFBP)-1 levels with birth weight and maternal anthropometric indices.

DESIGN

Longitudinal prospective study.

SETTING

Academic Institutions and a Tertiary Care Maternity Hospital.

PARTICIPANTS

Women with uncomplicated singleton pregnancy (N = 35) and their newborns.

MEASUREMENTS

Maternal weight, height, symphysiofundal height and serum levels of IGF-I, IGF-II, IGFBP-1 were measured thrice during the antenatal period, within 24 h of delivery and at 6 weeks and 6 months postpartum. Newborn anthropometric indices were recorded at birth, and at 6 weeks and 6 months of age. Cord blood levels of IGF-1, IGF-II, IGFBP-1, paternal height and weight, and placental weight measured.

RESULTS

Maternal and cord blood IGF-I levels were lower than values reported for Caucasians. All newborns showed adequate growth at birth, and up to 6 months of age. Cord blood IGF-1 positively correlated with chest circumference (r = 0.4532, P = 0.0262), IGFBP-1, negatively with birth weight (r = -0.4024, P = 0.0461) and IGF-II had no effect. Cord blood IGF-I positively correlated with maternal levels at 28 +/- 2 (r = 0.4571, P = 0.0247) and 36 +/- 2 (r = 0.4291, P = 0.0364) weeks of amenorrhoea, whereas IGF-II and IGFBP-1 did not correlate with maternal values. Maternal IGF-I, IGF-II and IGFBP-1 did not correlate with newborn or maternal anthropometric indices. Placental weight correlated significantly with birth weight (r = 0.5299, P = 0.0348) and head circumference (r = 0.5031, P = 0.0470).

CONCLUSIONS

Cord blood IGFBP-1 and placental weight appear to be determinants of birth weight variation even among appropriately grown for gestational age newborns.

Resolution of diabetes mellitus but not acromegaly in a cat with a pituitary macroadenoma treated with hypofractionated radiation

The use of insulin-like growth factor 1 assays in the diagnosis and subsequent monitoring after radiotherapy of an acromegalic cat with a secretory pituitary adenoma and secondary insulin-resistant diabetes mellitus is described. Diabetes resolved, and exogenous insulin was no longer required for the maintenance of normoglycaemia 10 months after completion of a course of hypofractionated radiotherapy. However, insulin-like growth factor 1 remained elevated, and the cat's size and appetite continued to increase. It is suggested that radiotherapy may decrease growth hormone concentration to a level such that diabetogenic effects are no longer evident but not to a level required to decrease insulin-like growth factor 1 secretion.

Intrauterine release of progesterone antagonist ZK230211 is feasible and results in novel endometrial effects: a pilot study

BACKGROUND

Continuous administration of progesterone antagonists (PAs) results in endometrial suppression and amenorrhoea in several model systems. We compared the effects of intrauterine release of a highly specific PA, ZK230211, to those of a progestin using the levonorgestrel-releasing intrauterine system (LNG-IUS).

METHODS

Forty-two women were randomly fitted with an IUS releasing either ZK230211 at a rate 1, 4 or 8 microg/24 h (ZK-IUS) or LNG (at 20 microg/24 h, LNG-IUS) at 4-8 weeks before hysterectomy. Bleeding patterns, endometrial morphology and content of ZK230211, and various immunohistochemistries (IHCs) were evaluated.

RESULTS

Days of bleeding and spotting were unchanged by the use of ZK-IUSs but were increased by LNG-IUS (P < 0.01). ZK230211 was measurable in all endometrial specimens. Endometrium was partly suppressed in 9-30% of women following the use of ZK-IUSs, and in 67% after LNG-IUS. IHCs for Ki-67 and phosphorylated histone H3 were not suggestive of proliferative activity in any group. Compared to LNG, progesterone receptor (PR) was increased following ZK230211 in surface epithelium (all three doses P < 0.01-P < 0.05) and stroma at 4 microg/24 h (P < 0.05). Although low, androgen receptor staining was higher in endothelial epithelium following LNG than ZK230211 (P < 0.05). Insulin-like growth factor-binding protein-1 (IGFBP-1) was detectable only following LNG (P < 0.0001).

CONCLUSIONS

Short-term intrauterine release of ZK230211 did not change bleeding patterns or result in endometrial suppression. Expression of proliferation markers was low following the use of both IUSs. Absence of IGFBP-1 and increase in PR reflect the PA effects of ZK230211.

Predicting preterm delivery in asymptomatic patients with prior preterm delivery by measurement of cervical length and phosphorylated insulin-like growth factor-binding protein-1

OBJECTIVE

To evaluate the efficacy of cervical length measurement in combination with a bedside assessment of phosphorylated insulin-like growth factor-binding protein-1 (phIGFBP-1) as a predictor of preterm delivery in asymptomatic pregnant women with a history of preterm birth.

METHODS

Cervical length was measured using transvaginal sonography at 22-24 weeks of gestation in 105 singleton pregnancies and a rapid strip test was performed to detect phIGFBP-1 in cervical secretions from 24 to 34 weeks. Receiver-operating characteristics (ROC) curves were constructed to compare the performance of phIGFBP-1 at different gestational ages, and cervical length at 22-24 weeks, in predicting preterm delivery.

RESULTS

The rate of spontaneous delivery before 37 and 34 weeks was 23.8% and 11.4%, respectively. Women with cervical lengths less than 20 mm had a risk of spontaneous preterm delivery before 34 and 37 weeks of 43.5% and 69.6%, respectively. The performance of phIGFBP-1 levels as a predictor of preterm delivery was significantly higher when the test was carried out at 30 weeks' gestation. Cervical assessment in combination with phIGFBP-1 at 30 weeks had the steepest ROC curve (area under the curve=0.93; 95% CI, 0.88-0.98, P<0.001).

CONCLUSION

Both cervical length and phIGFBP-1 measurement are useful in the prediction of preterm delivery in patients with a history of preterm birth and the combined method of measuring cervical length at 22-24 weeks and phIGFBP-1 at 30 weeks improves upon either method used alone.

Cervical phIGFBP-1 in the evaluation of the risk of preterm delivery

BACKGROUND

To evaluate the accuracy of the decidual phosphorylated isoform of insulin-like growth factor binding protein-1 in endocervical secretions to predict premature delivery in symptomatic and asymptomatic pregnant women.

METHODS

The study included 332 pregnant women: 109 symptomatic patients (study group) and 223 asymptomatic women (control group). For all women, qualitative and quantitative assessment of the decidual phosphorylated isoform of insulin-like growth factor binding protein-1 in endocervical secretions was carried out, but the quantitative assay was finally performed in 282 of 332. Student's test, the chi2 test, and Fisher's exact test were used as appropriate.

RESULTS

The phosphorylated insulin-like growth factor binding protein-1 qualitative test was positive in 35 of 301 women (11.6%) and 11 (31.4%) of them delivered before 37 weeks; in the remaining 266 women with a negative test, there were 11 (4.7%) premature deliveries (relative risk = 5.8; 95% CI = 3.3-10.3). The mean values of quantitative phosphorylated isoform of insulin-like growth factor binding protein-1 were 56.9 microg/l (95% CI = 40.7-73.1) in cases of a positive qualitative test and 6.1 microg/l (95% CI = 4.0-8.3; p = 0.0001) in women with a negative result. The sensitivity, specificity, positive predictive value, and negative predictive value for phosphorylated isoform of insulin-like growth factor binding protein-1 test in symptomatic patients were 69.2%, 90.5%, 50%, and 95.6% respectively, while in the asymptomatic patients they were 22.2%, 91.8%, 11.8%, and 96% respectively.

CONCLUSIONS

The phosphorylated isoform of insulin-like growth factor binding protein-1 in cervical secretions is a potential specific marker for preterm delivery occurring before 37 weeks. This test may have an important role in the management of women presenting with symptoms suggestive of preterm labour.

Metabolic hormones regulate insulin-like growth factor binding protein-1 mRNA levels in primary cultured salmon hepatocytes; lack of inhibition by insulin

IGF-binding proteins (IGFBPs) modulate the effects of the IGFs, major stimulators of vertebrate growth and development. In mammals, IGFBP-1 inhibits the actions of IGF-I. Rapid increases in circulating IGFBP-1 occur during catabolic states. Insulin and glucocorticoids are the primary regulators of circulating IGFBP-1 in mammals. Insulin inhibits and glucocorticoids stimulate hepatocyte IGFBP-1 gene expression and production. A 22 kDa IGFBP in salmon blood also increases during catabolic states and has recently been identified as an IGFBP-1 homolog. We examined the hormonal regulation of salmon IGFBP-1 mRNA levels and protein secretion in primary cultured salmon hepatocytes. The glucocorticoid agonist dexamethasone progressively increased hepatocyte IGFBP-1 mRNA levels (eightfold) and medium IGFBP-1 immunoreactivity over concentrations comparable with stressed circulating cortisol levels (10(-9) -10(-6) M). GH progressively reduced IGFBP-1 mRNA levels (0.3-fold) and medium IGFBP-1 immunoreactivity over physiological concentrations (5 x 10(-11)-5 x 10(-9) M). Unexpectedly, insulin slightly increased hepatocyte IGFBP-1 mRNA (1.4-fold) and did not change medium IGFBP-1 immunoreactivity over physiological concentrations and above (10(-9) -10(-6) M). Triiodothyronine had no effect on hepatocyte IGFBP-1 mRNA, whereas glucagon increased IGFBP-1 mRNA (2.2-fold) at supraphysiological concentrations (10(-6) M). This study suggests that the major inhibitory role of insulin in the regulation of liver IGFBP-1 production in mammals is not found in salmon. However, regulation of salmon liver IGFBP-1 production by other metabolic hormones is similar to what is found in mammals.

Insulin-like growth factor system components in the periodontium during tooth root resorption and early repair processes in the rat

There is evidence that growth factors, such as the insulin-like growth factors (IGFs), are involved in biological and pathological processes in oro-dento-facial tissues. To investigate their roles in tooth movement, root resorption, and repair, the occurrence of components of the IGF system, including the ligands IGF-I and -II, the IGF receptor 1 (IGF1R) and six IGF-binding proteins (IGFBP-1 to -6), was investigated by immunohistochemistry on sections from rat maxillae where the first molar had been moved mesially by means of an orthodontic appliance for 9 d to induce root resorption. After force deactivation on day 0, early repair was studied after a further 5, 7, 10, 12, 14, and 17 d. The immunostaining pattern in the periodontal ligament, cementum, and bone of control animals showed similarities known from studies in human teeth. Increased immunostaining for nearly all components in pressure sides and resorption lacunae indicated an involvement in resorption processes and clastic activities. During early stages of repair, the occurrence of several components (e.g. IGF-II, IGFBP-5 or -6) within lacunae and in cementoblasts showed an involvement in the resorption-repair sequence, which is considered to be a coupling process as known from bone.

Proteomic analysis of amniotic fluid in pregnancies with Down syndrome

Proteomic analysis is widely used for the detection of diagnostic markers. In the present study amniotic fluid supernatants (AFS) from pregnancies with Down syndrome (DS) fetuses and from chromosomally normal fetuses in the 17th week of gestation were analyzed by 2-DE. Gel comparison revealed significant differences in the two groups. Spots with different expression levels were excised and proteins were identified by MALDI-MS and nano-ESI-MS/MS. Splicing factor arginine/serine-rich 4 (SFRS4; Q08170) was present only in AFS from DS fetuses and completely absent in the control group. Quantitative differences were detected for alpha-1-microglobulin (AMBP; P02760), collagen alpha 1 (I) chain (CO1A1; P02452), collagen alpha 1 (III) chain (CO3A1; P02461), collagen alpha 1 (V) chain d (CO5A1; P20908), and basement membrane-specific heparin sulfate proteoglycan core protein (PGBM; P98160). These proteins were increased in cases with DS, whereas protein IBP-1 (P08833) was decreased by 40% compared with chromosomally normal fetuses. Four proteins, CO1A1, CO3A1, CO5A1, and PGBM, appeared as fragments. As differentially expressed proteins were present in all pregnancies with DS tested, they may represent useful potential markers for prenatal diagnosis. However, for protein biomarkers to be of any clinical utility, systematic analysis of the maternal serum should be conducted.

Factors Predicting Labor Induction Success: A Critical Analysis

Because of the risk of failed induction of labor, a variety of maternal and fetal factors as well as screening tests have been suggested to predict labor induction success. Certain characteristics of the woman (including parity, age, weight, height and body mass index), and of the fetus (including birth weight and gestational age) are associated with the success of labor induction; with parous, young women who are taller and lower weight having a higher rate of induction success. Fetuses with a lower birth weight or increased gestational age are also associated with increased induction success. The condition of the cervix at the start of induction is an important predictor, with the modified Bishop score being a widely used scoring system. The most important element of the Bishop score is dilatation. Other predictors, including transvaginal ultrasound (TVUS) and biochemical markers [including fetal fibronectin (fFN)] have been suggested. Meta-analyses of studies identified from MEDLINE, PubMed, and EMBASE and published from 1990 to October 2005 were performed evaluating the use of TVUS and fFN in predicting labor induction success in women at term with singleton gestations. Both TVUS and Bishop score predicted successful induction [likelihood ratio (LR)=1.82, 95% confidence interval (CI)=1.51-2.20 and LR=2.10, 95%CI=1.67-2.64, respectively]. As well, fFN and Bishop score predicted successful induction (LR=1.49, 95%CI=1.20-1.85, and LR=2.62, 95%CI=1.88-3.64, respectively). Although TVUS and fFN predicted successful labor induction, neither has been shown to be superior to Bishop score. Further research is needed to evaluate these potential predictors and insulin-like growth factor binding protein-1 (IGFBP-1), another potential biochemical marker.

Local changes in the insulin-like growth factor system in human skeletal muscle assessed by microdialysis and arterio-venous differences technique

IGF-I plays a direct role in whole body glucose homeostasis primarily by stimulating skeletal muscle glucose uptake. IGF-I is also involved in exercise induced muscle hypertrophy. Knowledge regarding local changes in muscle IGF-I bioavailability and its regulation by IGFBPs at rest and during exercise is limited. We have therefore explored changes in total IGF-I levels as well as circulating IGFBP levels and their post-translational modifications over an exercising leg. For the first time we have determined IGF-I levels in exercising skeletal muscle microdialysate in an attempt to assess local IGF-I bioavailability. Eighteen healthy young men performed one legged knee-extension exercise during 45min. Blood samples were taken from the femoral artery and vein of the exercising leg. No significant differences between arterial and venous concentrations of total IGF-I or IGFBP-1 were detected over the leg at any time. IGF-I concentrations increased significantly during exercise in the artery but not in the vein. Total IGFBP-1 increased after exercise in both artery and vein. The increase in non-plus less phosphorylated forms of IGFBP-1 was less pronounced and did not reach statistical significance. The proportion of fragmented IGFBP-3 (IGFBP-3 proteolysis) assessed by Western immunoblotting did not change significantly during or after exercise. Although optimization and validation of IGF-I determinations in muscle microdialysate (md) will be required, our first results using this technique demonstrate a significant 2-fold increase in mdIGF-I collected during and after exercise. We conclude that determination of A-V-differences appears to be of limited value in the assessments of local muscle change in the IGF-system. A substantial release of IGF-I during short time is required to detect significant change in the large circulating store of IGF-I. We suggest that an optimized and validated microdialysis technique for determination of local IGF-I may be advantageous in future studies.

Forkhead transcription factor FOXO1A is critical for induction of human decidualization

Experiments utilizing RNA interference technology were performed to determine whether the forkhead transcription factor FOXO1A, a member of the FOXO family of proteins, plays a critical role in the induction of human uterine decidualization. Human decidual fibroblast cells were decidualized in vitro for 6 days with medroxyprogester-one, estradiol, and dibutyryl cAMP in the presence or absence of a highly specific FOXO1A small interfering RNA (siRNA) that inhibits FOXO1A mRNA and protein expression by more than 80%. RNA and proteins were extracted from the cells at 0, 2, 4, and 6 days. FOXO1A and IGFBP-1 proteins were determined by immunoblotting; and intracellular mRNA levels for several decidualization marker genes were determined by real-time PCR. Exposure of the cells to FOXO1A siRNA in five separate experiments resulted in a 40-75% inhibition of prolactin, IGFBP-1, tissue inhibitor of metalloproteinase 3 (TIMP3), somatostatin and endometrial bleeding-associated factor (EBAF) mRNAs, all of which are markedly induced during the decidualization process. In contrast, actin and GAPDH mRNA levels did not change during decidualization. The inhibition of mRNA levels was first noted at day 2 and persisted for the remainder of each experiment. Western blot analysis indicated that the FOXO1A siRNA inhibited IGFBP-1 protein expression by 60-80%. Decidual fibroblast cells exposed in an identical manner to a control RNA that had no effect on FOXO1A expression caused only a 0-15% inhibition of the marker genes and IGFBP-1 protein. Taken together, these findings strongly suggest a critical role for FOXO1A in the induction of human decidualization.

Improvement in insulin sensitivity without concomitant changes in body composition and cardiovascular risk markers following fixed administration of a very low growth hormone (GH) dose in adults with severe GH deficiency

OBJECTIVE

Untreated GH-deficient adults are predisposed to insulin resistance and excess cardiovascular mortality. We showed previously that short-term treatment with a very low GH dose (LGH) enhanced insulin sensitivity in young healthy adults. The present study was therefore designed to explore the hypothesis that LGH, in contrast to the standard GH dose titrated to normalize serum IGF-I levels (SGH), may have differing effects on insulin sensitivity, body composition, and cardiovascular risk markers [lipid profile, C-reactive protein (CRP), interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-alpha) and adiponectin] in adults with severe GH deficiency.

PATIENTS AND METHODS

In this 12-month open, prospective study, 25 GH-deficient adults were randomized to receive either a fixed LGH (0.10 mg/day, n = 13) or SGH (mean dose 0.48 mg/day, n = 12), and eight age- and body mass index (BMI)-matched GH-deficient adults acted as untreated controls. Fasting blood samples were collected at baseline and at months 1, 3, 6, 9 and 12. Assessments of insulin sensitivity, using the hyperinsulinaemic euglycaemic clamp technique, and body composition, using dual-energy X-ray absorptiometry, were performed at baseline and at month 12.

RESULTS

The LGH decreased fasting glucose levels (P < 0.01) and enhanced insulin sensitivity (P < 0.02), but body composition, nonesterified fatty acid (NEFA) levels and cardiovascular risk markers were unchanged. The SGH did not modify insulin sensitivity, decreased truncal fat mass (P < 0.05), CRP (P < 0.05) and IL-6 (P < 0.05) levels, and increased NEFA levels (P < 0.05). No changes were observed with the untreated controls.

CONCLUSION

Our data indicate that, in contrast to the SGH, fixed administration of the LGH enhances insulin sensitivity with no apparent effects on body composition, lipolysis and other surrogate cardiovascular risk markers in adults with severe GH deficiency. Thus, the LGH may potentially be a beneficial replacement dose in reducing type 2 diabetes risk in adults with severe GH deficiency.

Biomarkers of adult and developmental neurotoxicity

Neurotoxicity may be defined as any adverse effect on the structure or function of the central and/or peripheral nervous system by a biological, chemical, or physical agent. A multidisciplinary approach is necessary to assess adult and developmental neurotoxicity due to the complex and diverse functions of the nervous system. The overall strategy for understanding developmental neurotoxicity is based on two assumptions: (1) significant differences in the adult versus the developing nervous system susceptibility to neurotoxicity exist and they are often developmental stage dependent; (2) a multidisciplinary approach using neurobiological, including gene expression assays, neurophysiological, neuropathological, and behavioral function is necessary for a precise assessment of neurotoxicity. Application of genomic approaches to developmental studies must use the same criteria for evaluating microarray studies as those in adults including consideration of reproducibility, statistical analysis, homogenous cell populations, and confirmation with non-array methods. A study using amphetamine to induce neurotoxicity supports the following: (1) gene expression data can help define neurotoxic mechanism(s), (2) gene expression changes can be useful biomarkers of effect, and (3) the site-selective nature of gene expression in the nervous system may mandate assessment of selective cell populations.

Insulin-like growth factor-I and insulin are associated with the presence and advancement of adenomatous polyps

BACKGROUND & AIMS

Insulin and insulin-like growth factor-I (IGF-I) affect proliferation, differentiation, and apoptosis and are potential risk factors for colorectal cancer (CRC). Visceral obesity, possibly via hyperinsulinemia, has also been linked to CRC risk. We evaluated the relationship of insulin, IGF-I, insulin-like growth factor binding protein (IGFBP) 3, and visceral adipose tissue (VAT) in subjects with adenomatous polyps, the precursor lesion of colorectal cancer.

METHODS

Participants were asymptomatic subjects who underwent screening flexible sigmoidoscopy (FSG) within the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Subjects underwent single-slice, computerized tomography scanning to measure VAT and serum fasting insulin, IGF-I, and IGFBP-3 measurements.

RESULTS

Four hundred fifty-eight subjects were enrolled, of which 202 subjects had an adenoma, 70 of which were an advanced adenoma. IGF-I (P = .02), IGF-I/IGFBP-3 ratio (P = .003), and insulin (P = .02) were significantly increased in subjects with adenomas compared with controls. In an unadjusted logistic regression analysis using sex-specific quartile cut points, subjects in quartile 4 in comparison with quartile 1 of IGF-I (odds ratio [OR] = 1.7; [95% CI: 1.0-2.9], Ptrend = .03), IGF-I/IGFBP-3 ratio (OR = 1.9 [95% CI: 1.1-3.3], Ptrend = .01), and insulin (OR = 2.1 [95% CI: 1.2-3.6], Ptrend = .04) were at increased risk of adenoma. When limiting the case group to advanced adenomas, the effect was more pronounced: IGF-I (OR = 2.8 [95% CI: 1.3-6.2], Ptrend = .006), IGF-I/IGFBP-3 ratio (OR = 2.3, [95% CI: 1.0-5.2], Ptrend = .04), and insulin (OR = 2.3 [95% CI: 1.1-4.9], Ptrend = .14). Visceral adipose tissue was not associated with adenoma risk.

CONCLUSIONS

Levels of IGF-I, ratio of IGF-I/IGFBP-3, and insulin are associated with adenomas and even more so with advanced adenomas. These data support the hypothesis that insulin and IGF-I may contribute to the development and advancement of adenomatous polyps.

Insulin-like growth factor II and binding proteins 1 and 3 from second trimester human amniotic fluid are associated with infant birth weight

The developing fetus begins to swallow amniotic fluid (AF) early in gestation, a process that results in ingestion of numerous growth factors. Our objectives were 2-fold: 1) to assess the concentration and distribution of insulin-like growth factor II (IGF II) and its binding proteins (BP) 1 and 3 in 2nd trimester amniotic fluid using ELISA, and 2) to establish whether concentrations of AF IGF II and its binding proteins IGF BP1 and 3, measured early in pregnancy, were associated with and predictive of infant birth weight. Birth weights were categorized using recently developed birth-weight-for-gestational-age percentiles for fetal growth in which infants < 10% were classified as SGA (small-for-gestational-age) and those > 90% as LGA (large-for-gestational-age). AF samples were collected after routine genetic testing (15.1 +/- 0.04 wk, range 12-20 wk) from 543 mother-infant pairs in Montreal, QC, Canada. Maternal and fetal characteristics were obtained from questionnaires and medical chart review. Multivariate regression analysis that controlled for maternal height, prepregnancy weight, smoking behavior, infant gender, gestational age, parity, as well as amniocentesis week showed that higher AF IGF BP1 was associated with lower birth weight (partial r2 = 0.0062). Regression analyses revealed that AF IGF BP3 was positively associated with birth weight within LGA and macrosomia subpopulations (partial r2 = 0.0283 and 0.0404, respectively). These results show that 2nd trimester AF IGF BP1, BP3, and IGF II may emerge as early indicators of fetal growth.

The IGF system in the neonatal ovine uterus

Postnatal development of the ovine uterus primarily involves uterine gland morphogenesis or adenogenesis. Adenogenesis involves the budding differentiation of the glandular epithelium (GE) from the luminal epithelium (LE) and then GE proliferation and coiling/branching morphogenetic development within the stroma between birth (postnatal day or PND 0) and PND 56. Insulin-like growth factor (IGF)-I and IGF-II mRNAs were previously found to be expressed only in the endometrial stroma, whereas the IGF receptor (IGF-1R) mRNA was most abundant in epithelia and in stroma, suggesting that an intrinsic IGF system regulates postnatal development of the uterus. Given that the biological activities of IGFs are modulated by a family of six IGF binding proteins (IGFBPs) and specific proteases, the objective was to determine the effects of age and estrogen disruption on expression of IGFs, IGFBPs and pregnancy-associated plasma protein A (PAPP-A or IGFBP-4 protease) in the ovine uterus. In Study One, circulating levels of IGF-I and IGF-II in the serum of neonatal ewes did not change between PND 0 and PND 56. Levels of immunoreactive IGF-I, IGF-II and IGF-1R protein were most abundant on the apical surface of the endometrial LE and GE. RT-PCR analyses detected expression of IGFBPs (3, 4, 5 and 6) as well as PAPP-A mRNAs in the uterus, but not IGFBP-1 and IGFBP-2 mRNAs. IGFBP-3 and IGFBP-4 mRNAs were expressed specifically in the endometrial stroma and myometrium and increased after birth. PAPP-A mRNA was expressed specifically in the endometrial stroma and increased after birth. In Study Two, ewes were treated from birth with estradiol-17beta valerate (EV), which reduces uterine growth and inhibits endometrial adenogenesis. On PNDs 14 and 56, IGFBP-3 mRNA was decreased in the uterus of EV-treated ewes, but IGF-1R and IGFBP-4 mRNAs were not affected. PAPP-A mRNA was increased by EV treatment on PND 14, but decreased on PND 56. These results support the hypothesis that an intrinsic IGF system in the uterus regulates epithelial-stromal interactions important for postnatal uterine growth and endometrial gland morphogenesis in the sheep.

Identification of proteins released by pancreatic cancer cells by multidimensional protein identification technology: a strategy for identification of novel cancer markers

The purpose of this study is to identify novel proteins released by cancer cells that are involved in extracellular matrix (ECM) remodeling using small-volume samples and automated technology. We applied multidimensional protein identification technology (MudPIT), which incorporates two-dimensional capillary chromatography coupled to tandem mass spectrometry to small quantities of serum-free supernatants of resting or phorbol ester-activated Suit-2 pancreatic cancer cells. Selected markers were validated in additional pancreatic cancer cell lines, primary cancers, and xenografted cancer cells. MudPIT analysis of 10 microl of supernatants identified 46 proteins, 21 of which are classified as secreted, and 10 have never been associated with pancreatic cancer. These include CSPG2/versican, Mac25/angiomodulin, IGFBP-1, HSPG2/perlecan, syndecan 4, FAM3C, APLP2, cyclophilin B, beta2 microglobulin, and ICA69. Evidence that cancer cells release these proteins in vivo was obtained for CSPG2/versican and Mac25/angiomodulin by immunohistochemistry on both primary pancreatic cancers and in a model consisting of Suit-2 cells embedded in an amorphous matrix and implanted in athymic mice. MudPIT allowed efficient and rapid identification of proteins released by cancer cells, including molecules previously undescribed in the type of cancer analyzed. Our finding that pancreatic cancer cells secrete a series of proteoglycans, including versican, perlecan, syndecan 1 and 4, challenges the common view that fibroblasts of tumor stroma are the sole source of these molecules.

The use of biochemical markers in prenatal diagnosis of intrauterine growth retardation: insulin-like growth factor I, Leptin, and alpha-fetoprotein

OBJECTIVE

To determine the relation between weight deficit at birth and IGF-I, IGFBP-I, Leptin, and AFP levels in amniotic fluid after 14-18 weeks; to assess the diagnostic usefulness of these biochemical markers.

STUDY DESIGN

Longitudinal, prospective study. Amniocentesis was performed in pregnant women after 14-18 weeks of gestation.

STUDY POPULATION

86 controls, 18 IUGR <10 percentile, and 17 IUGR <5 percentile.

RESULTS

No significant correlation was found between severity of IUGR and IGF-I, IGFBP-I, or Leptin. AFP was inversely correlated with severity of IUGR; results for the IUGR <10 percentile were: S: 65.7%, SP: 56.9%, PPV: 38.3%, NPV: 80.3%, and an overall diagnostic capacity of 65.6%. Results for the IUGR <5 percentile were: S: 76.4%, SP: 54.8%, PPV: 21.6%, NPV: 93.4% were obtained, and an overall capacity of 70.6%.

CONCLUSIONS

Elevated values of AFP in amniotic fluid may help early detection of populations at risk of developing IUGR.

Insulin-like growth factor-binding protein-1 (IGFBP-1) mediates hypoxia-induced embryonic growth and developmental retardation

Although reduced fetal growth in response to hypoxia has been appreciated for decades, we have a poor understanding of the effects of hypoxia on embryonic development and the underlying cellular and molecular mechanisms. Here we show that hypoxia treatment not only resulted in embryonic growth retardation but also caused significant delay in developmental speed and the timing of morphogenesis in vital organs of zebrafish. Hypoxia strongly induced the expression of insulin-like growth factor (IGF)-binding protein (IGFBP)-1, a secreted protein that binds IGFs in extracellular environments. Hypoxia did not change the expression levels of IGFs, IGF receptors, or other IGFBPs. The hypothesis that elevated IGFBP-1 mediates hypoxia-induced embryonic growth retardation and developmental delay by binding to and inhibiting the activities of IGFs was tested by loss- and gain-of-function approaches. Knockdown of IGFBP-1 significantly alleviated the hypoxia-induced growth retardation and developmental delay. Overexpression of IGFBP-1 caused growth and developmental retardation under normoxia. Furthermore, reintroduction of IGFBP-1 to the IGFBP-1 knocked-down embryos restored the hypoxic effects on embryonic growth and development. When tested in vitro with cultured zebrafish embryonic cells, IGFBP-1 itself had no mitogenic activity, but it inhibited IGF-1- and IGF-2-stimulated cell proliferation. This inhibitory effect was abolished when IGF-1 or IGF-2 was added in molar excess, suggesting that IGFBP-1 inhibits embryonic growth and development by binding to and inhibiting the activities of IGFs. The induction of IGFBP-1 expression may be a conserved physiological mechanism to restrict the IGF-stimulated growth and developmental process under hypoxic stress.

Salmon serum 22 kDa insulin-like growth factor-binding protein (IGFBP) is IGFBP-1

Western ligand blotting of salmon serum typically reveals three insulin-like growth factor (IGF) binding proteins (IGFBPs) at 22, 28 and 41 kDa. Physiologic regulation of the 22 kDa IGFBP is similar to that of mammalian IGFBP-1; it is increased in catabolic states such as fasting and stress. On the other hand, its molecular mass on Western ligand blotting is closest to mammalian IGFBP-4. The conflict between physiology and molecular mass makes it difficult to determine the identity of the 22 kDa IGFBP. This study therefore aimed to identify the 22 kDa IGFBP from protein and cDNA sequences. The 22 kDa IGFBP was purified from chinook salmon serum by a combination of IGF-affinity chromatography and reverse-phase chromatography. The N-terminal aminoacid sequence of the purified protein was used to design degenerate primers. Degenerate PCR with liver template amplified a partial IGFBP cDNA, and full-length cDNA was obtained by 5'- and 3'-rapid amplification of cDNA ends (RACE). The 1915-bp cDNA clone encodes a 23.8 kDa IGFBP, and its N-terminal amino-acid sequence matched that of purified 22 kDa IGFBP. Sequence comparison with six human IGFBPs revealed that it is most similar to IGFBP-1 (40% identity and 55% similarity). These findings indicate that salmon 22 kDa IGFBP is IGFBP-1. Salmon IGFBP-1 mRNA is predominantly expressed in the liver, and its expression levels appear to reflect circulating levels. The 3'-untranslated region of salmon IGFBP-1 mRNA contains four repeats of the nucleotide sequence ATTTA, which is involved in selective mRNA degradation. In contrast, amino-acid sequence analysis revealed that salmon IGFBP-1 does not have an Arg-Gly-Asp (RGD) integrin recognition sequence nor a Pro, Glu, Ser and Thr (PEST)-rich domain (a segment involved in rapid turnover of protein), both of which are characteristic of mammalian IGFBP-1. These findings suggest that association with the cell surface and turnover rate may differ between salmon and mammalian IGFBP-1.

Significance of detecting insulin-like growth factor binding protein-1 in cervicovaginal secretions: comparison with nitrazine test and amniotic fluid volume assessment

OBJECTIVES

The diagnosis of premature rupture of membranes (PROM) is sometimes challenging, and common diagnostic tests are of limited value in the diagnosis. We aimed to study the accuracy of detecting insulin-like growth factor binding protein-1 (IGFBP-1) in vaginal fluid by a rapid dipstick method in comparison with the nitrazine test and amniotic fluid index (AFI) and we studied the predictivity of these methods on the latency of pregnancy in patients with suspected PROM.

MATERIAL AND METHOD

One hundred and fifty-one patients (36 definite PROM, 35 no PROM and 80 suspected PROM) at 20-42 weeks' gestation were included in the study. Patients with preterm labor and PROM, patients at <20 gestational weeks, and those with multiple pregnancies were excluded. IGFBP-1 in the cervicovaginal fluid was measured by a rapid dipstick method (PROM test). AFI was measured by the four-quadrant method and an AFI of <80 mm was considered as oligohydroamnios.

RESULTS

The sensitivity, specificity and accuracy of the nitrazine test, the PROM test and AFI were 97, 16 and 56%, 97, 97 and 97% and 94, 91 and 92%, respectively. The nitrazine test results were affected by vaginal discharge but the PROM test results were not affected. Only a positive PROM test was associated with delivery within 7 days [odds ratio (OR) 12; 95% confidence interval (CI) 4.2-35, p < 0.001].

CONCLUSION

The dipstick method of detecting IGFBP-1 in the vaginal fluid is a rapid, reliable and noninvasive method. The PROM test is the most accurate diagnostic test and predictor of latency in patients with suspected PROM.

Serum levels of insulin, IGF-1, and IGFBP-1 in pre-eclampsia and eclampsia

OBJECTIVES

To investigate whether the serum concentrations of insulin, insulin-like growth factor-1 (IGF-1), and insulin-like growth factor binding protein-1 (IGFBP-1) were altered in women with mild pre-eclampsia, severe pre-eclampsia, and eclampsia.

METHODS

In this prospective study, we investigated 20 mild pre-eclamptic, 20 severe pre-eclamptic, and 20 eclamptic patients in the third trimester. The control group consisted of 20 healthy pregnant women. Serum levels of insulin, IGF-1, and IGFBP-1 were measured.

RESULTS

In patients with eclampsia, serum levels of IGF-1 were lower, and IGFBP-1 were higher, respectively, than control and other study groups (P<0.001) The values of IGF-1 in mild pre-eclampsia and severe pre-eclampsia were lower compared with control groups (both P<0.01), but there were no differences between mild and severe pre-eclampsia. The serum levels of IGFBP-1 in severe pre-eclampsia were higher compared with control groups (P<0.01), but there was no statistical difference between mild pre-eclampsia and other groups.

CONCLUSIONS

IGF-1 was lower, and IGFBP-1 was higher in pre-eclamptic and eclamptic patients than controls, these alterations were related to the severity of pre-eclampsia.

Expression of the insulin-like growth factor binding proteins during postnatal development of the murine mammary gland

IGF-I and IGF-II have known roles in postnatal development of the mammary gland. In contrast, the function of the high-affinity IGF binding proteins (IGFBPs) in mammary growth and differentiation is largely unknown. The goal of these studies was to determine the patterns and levels of IGFBP expression during postnatal growth of the murine mammary gland. IGFBP-1 to -5 proteins were detected in mammary tissue by immunoblotting during both pubertal and pregnancy-induced growth; however, the regulation of each IGFBP was distinct through these developmental periods. IGFBP-2 to -5 mRNAs were readily detectable in the developing gland by in situ hybridization analyses but were expressed in distinct cellular sites. IGFBP-3 and -5 mRNAs were expressed in the developing epithelial structures and in isolated stromal cells during ductal growth and alveolar differentiation. In the terminal end buds (TEBs), IGFBP-3 mRNA expression was consistent with its localization in the cap cells, whereas IGFBP-5 was highly expressed in the body cells of the TEB. In contrast, IGFBP-2 and -4 mRNAs were expressed predominantly in stromal cells. IGFBP-2 mRNA was localized to restricted sites in the neck of the TEB and along the ductal structures, whereas IGFBP-4 mRNA was widely expressed in the stroma surrounding the epithelial structures. Protein and mRNA expression for most of the IGFBPs decreased during lactational ages. Levels of IGFBP-2 and -5 protein increased after pup removal during forced involution. Taken together, these data suggest important functions for the family of IGFBPs during postnatal growth and differentiation of the mammary epithelium.

Value of cervical phosphorylated insulinlike growth factor binding protein-1 in the prediction of preterm labor

OBJECTIVE

To determine the value of cervical phosphorylated insulinlike growth factor binding protein-1 (IGFBP-1) in the prediction of preterm labor.

STUDY DESIGN

In this prospective study, 77 pregnant women, gestational age 24-36 weeks, were enrolled in the study. Twenty women with completely healthy pregnancies formed the control group. Fifty-seven women with signs and symptoms of preterm labor formed the study group. Phosphorylated IGFBP-1 in cervical secretions was assessed in all patients by using a qualitative, immunochromatographic, 1-step dipstick test. Cervical length was measured by transvaginal sonography.

RESULTS

The IGFBP-1 test was negative in all patients in the control group (n = 20), and all of them delivered after 37 weeks, while the test was positive in 15 of 45 (33.3%) patients in the study group. The correlation between cervical length and gestational age at the time of delivery in patients with a positive phosphorylated IGFBP-1 test (n = 15) was significant (r = .553, P = .03). The sensitivity, specificity, positive predictive value and negative predictive value for the phosphorylated IGFBP-1 test were 78%, 87%, 73% and 90%, respectively.

CONCLUSION

Use of a 1-step dipstick test for detecting phosphorylated IGFBP-1 in cervical secretions is of value in the prediction of preterm labor. The high negative predictive value of the test may be useful in avoiding unnecessary medical interventions.

Insulin-like growth factor binding protein 1 and human embryonic development during 6 - 10 gestational weeks

BACKGROUND

Insulin-like growth factor binding protein-1 (IGFBP-1), which is a carrier of Insulin-like growth factors (IGFs) regulates the fetal development by working as an active factor controlling the combination of IGFs with their receptors. This study was designed to investigate the relationship between IGFBP-1 and human embryonic development during weeks 6 - 10 of gestation.

METHODS

A total of 44 pregnant women with singleton pregnancy were divided into two groups: one with abnormal embryo development (n = 32) and the other with normal embryo development (n = 12). Enzyme-linked immunosorbent assay (ELISA) was employed to detect IGFBP-1 levels in maternal serum and decidual tissue. The expression of IGFBP-1 mRNA in deciduas was examined by reverse transcription polymerase chain reaction (RT-PCR) technique.

RESULTS

The level of IGFBP-1 protein in maternal serum was significantly higher in the abnormal group [(125.36 +/- 47.93) micro g/ml] than in the normal group [(70.72 +/- 21.21) micro g/ml]. Both of IGFBP-1 and IGFBP-1 mRNA in deciduas were higher in abnormal group [(1.60 +/- 1.39) micro g/ml and 1.66 +/- 1.64, respectively] than in the normal group [(0.35 +/- 0.23) micro g/ml and 0.40 +/- 0.20, respectively]. The level of IGFBP-1 in maternal serum was positively correlated with IGFBP-1 mRNA (r = 0.90, P < 0.05) and IGFBP-1 protein (r = 0.92, P < 0.05) in decidual tissue.

CONCLUSIONS

During weeks 6 - 10 of gestation, abnormal embryonic development is correlated with elevated IGFBP-1. The level of IGFBP-1 in maternal serum is related to the concentrations of IGFBP-1 mRNA and IGFBP-1 in decidual tissue. The IGFBP-1 level in maternal serum may be used as a predictive marker to evaluate embryonic development.