OBJECTIVETo study the effects of maternal folate deficiency on fetal growth and development and the methylation profiles of insulin-like growth factor system in the offspring rats.

METHODSTwenty-two Sprague-Dawley female rats were randomly assigned to two groups: a folate deficient group (n=12) and a control group (n=10). They were fed with folate deficient and normal diet respectively. Dams were mated after 2 weeks of feeding. Eight female rats from each group were pregnant. On the 20th day of gestation, the fetuses were delivered by caesarean section. Thirty-two fetal rats from each group were randomly selected and the body length and weight were measured. Eight fetal rats from each group were randomly selected and ELISA was used to measure the level of folate content, IGF-1 and IGFBP-3 in the fetal brain and liver. Three fetal rats from each group were randomly selected and methylated DNA immunoprecipitation sequencing (MeDIP-Seq) was used to detect the methylation level of insulin-like growth factor system in the fetal brain and liver. ELISA was used to measure the level of IGF-1 and IGFBP-3 in the maternal serum from both groups.

RESULTSThe mean fetal length and weight were lower in the folate deficient group than in the control group (P<0.05). The levels of IGF-1 and IGFBP-3 in the maternal serum, as well as folate content and IGFBP-3 in the fetal brain and liver were significantly lower in the folate deficient group than in the control group (P<0.05). The methylation levels of IGF-1R, IGF-2R, IGFBP-2, IGFBP-5, IGFBP-6 and IGFBP-7 in the fetal brain were higher in the folate deficient group than in the control group (P<0.05). The methylation levels of IGF-1R, IGF-2R, IGFBP-3 and IGFBP-5 in the fetal liver were higher in the folate deficient group than in the control group. The methylation of IGF-2 gene showed a significant reduction in the folate deficient group (P<0.05).

CONCLUSIONSMaternal folate deficiency may cause retardation of growth and development of the offspring, which is possibly associated with the changes of methylation profiles of insulin-like growth factors.

Animals ; Brain ; metabolism ; DNA Methylation ; Female ; Fetal Development ; Fetus ; metabolism ; Folic Acid Deficiency ; metabolism ; Insulin-Like Growth Factor Binding Protein 3 ; blood ; Insulin-Like Growth Factor I ; analysis ; Liver ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the correlation between methylation of insulin-like growth factor 1 (IGF-1) gene promoter and its placenta-specific expression and fetal macrosoma.

METHODSOne hundred twenty nine healthy pregnant women were recruited between April 2011 and March 2012. Baseline data were collected with self-report questionnaires. Real-time quantitative PCR was used to determine the expression of IGF-1 mRNA in the placenta. Methylation level of the IGF 1 gene was determined with matrix-assisted laser desorption/ionization-time of flight mass spectrometry.

RESULTSThe expression of IGF-1 in placenta and its methylation level showed no significant difference between macrosomic fetuses and controls. No linear correlation was found between IGF-1 mRNA expression and methylation level of IGF-1 promoter (r=0.128, P=0.295). IGF-1 promoter region in placenta showed a hypomethylation status. However, a positive correlation was found between IGF-1 expression and birth weight below 4260 g (r=0.264, P=0.022). The expression of IGF-1 mRNA was significantly higher in those with a birth weight below 4260 g, which suggested that placental IGF-1 expression may contribute to increased birth weight. In regard to fetal overgrowth, however, there seemed to be a negative correlation in which placental IGF-1 expression was downregulated to limit fetal overgrowth.

CONCLUSIONNo linear correlation was found between placental IGF-1 expression and methylation level of IGF-1 promoter with a hypomethylation status. The contribution of placental IGF-1 expression to birth weight is bidirectional. Increased expression seems to promote fetal growth, while decreased expressions may curb overgrowth, therefore control fetal growth in a relatively normal range.

Birth Weight ; DNA Methylation ; Female ; Fetal Macrosomia ; genetics ; Humans ; Infant, Newborn ; Insulin-Like Growth Factor I ; genetics ; Placenta ; metabolism ; Pregnancy ; Promoter Regions, Genetic ; RNA, Messenger ; analysis

OBJECTIVETo study the effect of L-alanyl-L-glutamine (Ala-Gln) on the levels of insulin-like growth factor-1 (IGF-1) and IGF-1 receptor (IGF-1R) in the intestinal tissues of low-birth-weight (LBW) newborn rats with hypoxia/reoxygenation-induced intestinal injury.

METHODSPregnant rats were fed with or without smoking. The rats born by those fed without smoking were included in group A; for the rats born by those fed with smoking, normal-birth-weight rats were included in group B, and LBW rats were randomly divided into control group (group C), hypoxia/reoxygenation (H/R) group (group D), and Ala-Gln group (group E). Each group consisted of 24 newborn rats. The rats in groups D and E received H/R treatment twice a day for three consecutive days to establish an intestinal injury model; the rats in group E were intraperitoneally injected with Ala-Gln (10 ml/kg) before daily H/R treatment, while those in groups C and D were given an equal dose of normal saline by intraperitoneal injections. On days 4, 7, and 10 after birth, 8 rats were sacrificed in each group to collect intestinal tissues. The IGF-1 levels in intestinal tissues were measured using ELISA, and IGF-1R levels were measured by immunohistochemistry.

RESULTSThere were no significant differences in IGF-1 and IGF-1R levels between groups A and B at all time points. The levels of IGF-1 and IGF-1R in group C kept increasing, were higher than those in other groups on day 7 (P<0.05), and reached a normal level on day 10, without significant differences compared with those in groups A and B. Group D had significantly lower IGF-1 and IGF-1R levels than group C at all time points (P<0.05). The levels of IGF-1 and IGF-1R in group E were lower than those in group C on days 4 and 7 (P<0.05), but they increased to approximately the levels in group C and were significantly higher than those in group D on day 10.

CONCLUSIONSIntrauterine and postnatal hypoxia may induce intestinal injury in LBW newborn rats, and parenteral administration of high-dose Ala-Gln can reduce hypoxia-induced intestinal injury. Therefore, Ala-Gln has a protective effect against hypoxia-induced intestinal injury.

Animals ; Birth Weight ; Dipeptides ; pharmacology ; Female ; Hypoxia ; metabolism ; Insulin-Like Growth Factor I ; analysis ; Intestines ; chemistry ; Male ; Pregnancy ; Rats ; Rats, Sprague-Dawley ; Receptor, IGF Type 1 ; analysis

Cows with different Insulin-like Growth Factor-I (IGF-I) concentrations showed comparable expression levels of hepatic growth hormone receptor (GHR). Suppressor of cytokine signaling 2 (SOCS2), could be responsible for additional inhibition of the GHR signal cascade. The aims were to monitor cows with high or low antepartal IGF-I concentrations (IGF-I(high) or IGF-I(low)), evaluate the interrelationships of endocrine endpoints, and measure hepatic SOCS2 expression. Dairy cows (n = 20) were selected (240 to 254 days after artificial insemination (AI)). Blood samples were drawn daily (day -17 until calving) and IGF-I, GH, insulin, thyroid hormones, estradiol, and progesterone concentrations were measured. Liver biopsies were taken (day 264 +/- 1 after AI and postpartum) to measure mRNA expression (IGF-I, IGFBP-2, IGFBP-3, IGFBP-4, acid labile subunit (ALS), SOCS2, deiodinase1, GHR1A). IGF-I concentrations in the two groups were different (p < 0.0001). However, GH concentrations and GHR1A mRNA expression were comparable (p > 0.05). Thyroxine levels and ALS expression were higher in the IGF-I(high) cows compared to IGF-I(low) cows. Estradiol concentration tended to be greater in the IGF-I(low) group (p = 0.06). It was hypothesized that low IGF-I levels are associated with enhanced SOCS2 expression although this could not be decisively confirmed by the present study.
Animals ; Cattle ; Estradiol/blood ; Female ; Growth Hormone/blood ; Insulin/blood ; Insulin-Like Growth Factor Binding Protein 2/analysis ; Insulin-Like Growth Factor Binding Protein 3/analysis ; Insulin-Like Growth Factor Binding Protein 4/analysis ; Insulin-Like Growth Factor I/*analysis/physiology ; Liver/chemistry ; Pregnancy/metabolism/physiology ; Pregnancy, Animal/*metabolism/physiology ; Progesterone/blood ; Suppressor of Cytokine Signaling Proteins/analysis ; Thyroid Hormones/blood

OBJECTIVETo study the effects of astragaloside on the expression of insulin-like growth factor-1 (IGF-1) and associated proteins in mice with viral myocarditis.

METHODSSixty-five 4-week-old BALB/C mice were randomly divided into 5 groups: normal control, astragaloside control, untreated myocarditis, low-dose and high-dose astragaloside-treated myocarditis. The BALB/C mice in the later three groups were intraperitoneally injected with CVB3. The low-dose and high-dose astragaloside-treated myocarditis groups were given astragaloside of 0.07 and 0.6 mg/kg•d, respectively by intragastric administration. Fifteen days later, the samples of blood and muscular tissues were obtained. The expression of IGF-1 in plasma was measured using ELISA. The levels of IGF-1 and associated proteins in muscular tissues were measured by immunohistochemistry. The expression of IGF-1 mRNA in muscular tissues was examined by RT-polymerase chain reaction (RT-PCR).

RESULTSThe expression of IGF-1 and associated proteins increased significantly in mice infected with CVB3. High-dose astragaloside treatment reduced the expression of IGF-1 and associated proteins, but low-dose astragaloside did not.

CONCLUSIONSHigh-dose astragaloside may reduce the expression of IGF-1 and associated proteins in mice with acute viral myocarditis, possibly thus providing protective effects on muscular tissues.

Acute Disease ; Animals ; Coxsackievirus Infections ; drug therapy ; metabolism ; Drugs, Chinese Herbal ; therapeutic use ; Enterovirus B, Human ; Insulin-Like Growth Factor Binding Protein 3 ; analysis ; Insulin-Like Growth Factor I ; analysis ; genetics ; Male ; Mice ; Mice, Inbred BALB C ; Myocarditis ; drug therapy ; metabolism ; Myocardium ; chemistry ; RNA, Messenger ; analysis ; Receptor, IGF Type 1 ; analysis ; Saponins ; therapeutic use ; Triterpenes ; therapeutic use

BACKGROUNDTissue-engineered bioartificial muscle-based gene therapy represents a promising approach for the treatment of heart diseases. Experimental and clinical studies suggest that systemic administration of insulin-like growth factor-1 (IGF-1) protein or overexpression of IGF-1 in the heart exerts a favorable effect on cardiovascular function. This study aimed to investigate a chronic stage after myocardial infarction (MI) and the potential therapeutic effects of delivering a human IGF-1 gene by tissue-engineered bioartificial muscles (BAMs) following coronary artery ligation in Sprague-Dawley rats.

METHODSLigation of the left coronary artery or sham operation was performed. Primary skeletal myoblasts were retrovirally transduced to synthesize and secrete recombinant human insulin-like growth factor-1 (rhIGF-1), and green fluorescent protein (GFP), and tissue-engineered into implantable BAMs. The rats that underwent ligation were randomly assigned to 2 groups: MI-IGF group (n = 6) and MI-GFP group (n = 6). The MI-IGF group received rhIGF-secreting BAM (IGF-BAMs) transplantation, and the MI-GFP group received GFP-secreting BAM (GFP-BAMs) transplantation. Another group of rats served as the sham operation group, which was also randomly assigned to 2 subgroups: S-IGF group (n = 6) and S-GFP group (n = 6). The S-IGF group underwent IGF-1-BAM transplantation, and S-GFP group underwent GFP-BAM transplantation. IGF-1-BAMs and GFP-BAMs were implanted subcutaneously into syngeneic rats after two weeks of operation was performed. Four weeks after the treatment, hemodynamics was performed. IGF-1 was measured by radioimmunoassay, and then the rats were sacrificed and ventricular samples were subjected to immunohistochemistry. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to examine the mRNA expression of bax and Bcl-2. TNF-α and caspase 3 expression in myocardium was examined by Western blotting.

RESULTSPrimary rat myoblasts were retrovirally transduced to secrete rhIGF-1 and tissue-engineered into implantable BAMs containing parallel arrays of postmitotic myofibers. In vitro, they secreted consistent levels of hIGF (0.4 - 1.2 µg×BAM(-1)×d(-1)). When implanted into syngeneic rat, IGF-BAMs secreted and delivered rhIGF. Four weeks after therapy, the hemodynamics was improved significantly in MI rats treated with IGF-BAMs compared with those treated with GFP-BAMs. The levels of serum IGF-1 were increased significantly in both MI and sham rats treated with IGF-BAM. The mRNA expression of bax was lower and Bcl-2 expression was higher in MI-IGF group than MI-GFP group (P < 0.05). Western blotting assay showed TNF-α and caspase 3 expression was lower in MI-IGF group than MI-GFP group after therapy.

CONCLUSIONSrhIGF-1 significantly improves left ventricular function and suppresses cardiomyocyte apoptosis in rats with chronic heart failure. Genetically modified tissue-engineered BAMs provide a method delivering recombinant protein for the treatment of heart failure.

Animals ; Apoptosis ; Caspase 3 ; analysis ; Desmin ; analysis ; Genetic Therapy ; Heart Failure ; pathology ; physiopathology ; therapy ; Insulin-Like Growth Factor I ; genetics ; secretion ; Myoblasts, Skeletal ; metabolism ; Myocytes, Cardiac ; pathology ; Rats ; Rats, Sprague-Dawley ; Recombinant Proteins ; secretion ; Retroviridae ; genetics ; Tissue Engineering ; Tumor Necrosis Factor-alpha ; analysis ; Ventricular Function, Left

OBJECTIVEA stable primary breast cancer model in liver-specific insulin-like growth factor 1 (IGF-1) deficient (LID) mice and control mice was established. To screen apoptosis related genes expression in different serum IGF-1 levels by gene chip and flow cytometry.

METHODSThe LID mice and control mice were used. Induction of breast cancer was achieved by using the 7,12-dimethylbenz(a) anthracene. Ginsenoside Rg3 was used to interfering therapy treatment. The incidence of breast cancer in every group was compared, and expression of apoptosis associated genes was detected by gene chip and flow cytometry.

RESULTSThe incidence of tumor in none ginsenoside Rg3 injected control mice was 66.7%. The incidence of tumor in ginsenoside Rg3 injected LID mice was 12.0% which was significantly lower than any other group (P < 0.05). The apoptosis percentage in none ginsenoside Rg3 injected control mice was (2.7 +/- 0.7)%. The apoptosis percentage in ginsenoside Rg3 injected LID mice was (14.0 +/- 1.7)%. The results of gene chip indicated that in contrast to LID mice, LTA, LTB, TNF-alpha, TRAIL, TRANCE, BLK, BOK, CASP8, TRAF5, and APAF1 genes were down-regulated, and LTBR, TRAF4 genes were up-regulated in the breast cancer tissues of control mice. Application of ginsenoside Rg3 therapy could change the expression of these genes.

CONCLUSIONSCirculating IGF-1 levels play a role in the onset and development of breast cancer. Degrade serum IGF-1 level is able to promote apoptosis by affecting the expression of a series of apoptosis related genes consequently inhibit the growth of breast cancer. There was a synergistic effect with the application of ginsenoside Rg3.

Animals ; Apoptosis ; Breast Neoplasms ; metabolism ; pathology ; Cell Proliferation ; Disease Models, Animal ; Female ; Insulin-Like Growth Factor I ; genetics ; metabolism ; Mice ; Mice, Knockout ; Oligonucleotide Array Sequence Analysis

To determine which genes are regulated by thyroid stimulating hormone (thyrotropin, TSH), insulin and insulin-like growth factor-1 (IGF-1) in the rat thyroid, we used the microarray technology and observed the changes in gene expression. The expressions of genes for bone morphogenetic protein 6, the glucagon receptor, and cyclin D1 were increased by both TSH and IGF-1; for cytochrome P450, 2c37, the expression was decreased by both. Genes for cholecystokinin, glucuronidase, beta, demethyl-Q 7, and cytochrome c oxidase, subunit VIIIa, were up-regulated; the genes for ribosomal protein L37 and ribosomal protein L4 were down-regulated by TSH and insulin. However, there was no gene observed to be regulated by all three: TSH, IGF-1, and insulin molecules studied. These findings suggest that TSH, IGF-1, and insulin stimulate different signal pathways, which can interact with one another to regulate the proliferation of thyrocytes, and thereby provide additional influence on the process of cellular proliferation.
Animals ; Bone Morphogenetic Protein 6 ; Bone Morphogenetic Proteins/biosynthesis ; Cell Line, Tumor ; Cyclin D1/biosynthesis ; *Gene Expression Profiling ; *Gene Expression Regulation ; Insulin/*biosynthesis/metabolism ; Insulin-Like Growth Factor I/*biosynthesis ; Models, Genetic ; *Oligonucleotide Array Sequence Analysis ; Rats ; Receptors, Glucagon/biosynthesis ; Thyroid Gland/*metabolism ; Thyrotropin/*biosynthesis/metabolism ; Time Factors

OBJECTIVETo label the primary articular chondrocytes overexpressing human insulin-like growth factor (hIGF 1) with green fluorescent protein (GFP) for repair of articular cartilage defects in rabbits.

METHODSGFP cDNA was inserted into pcDNA3.1 hIGF 1 to label the expression vector. The recombinant vector, pcGI, a mammalian expression vector with multiple cloning sites under two respective cytomegalovirus promoters/enhancers, was transfected into the primary articular chondrocytes with the help of lipofectamine. After the positive cell clones were selected by G418, G418-resistant chondrocytes were cultured in medium for 4 weeks. The stable expression of hIGF 1 in the articular chondrocytes was determined by in situ hybridization and immunocytochemical analysis and the GFP was confirmed under a fluorescence microscope. Methyl thiazolyl tetrazolium (MTT) and flow cytometer methods were employed to determine the effect of transfection on proliferation of chondrocytes. Gray value was used to analyze quantitatively the expression of type II collagen.

RESULTSThe expression of hIGF 1 and GFP was confirmed in transfected chondrocytes by in situ hybridization, immunocytochemical analysis and fluorescence microscope observation. Green articular chondrocytes overexpressing hIGF 1 could expand and maintain their chondrogenic phenotypes for more than 4 weeks. After the transfection of IGF 1, the proliferation of chondrocytes was enhanced and the chondrocytes could effectively maintain the expression of type II collagen.

CONCLUSIONSThe hIGF 1 eukaryotic expression vector containing GFP marker gene has been successfully constructed. GFP, which can be visualized in real time and in situ, is stably expressed in articular chondrocytes overexpressing hIGF 1. The labeled articular chondrocytes overexpressing hIGF 1 can be applied in cell-mediated gene therapy as well as for other biomedical purposes of transgenic chondrocytes.

Animals ; Cartilage, Articular ; metabolism ; Cells, Cultured ; Chondrocytes ; metabolism ; Flow Cytometry ; Genetic Markers ; Genetic Therapy ; Genetic Vectors ; Green Fluorescent Proteins ; genetics ; Insulin-Like Growth Factor I ; genetics ; metabolism ; Luminescent Agents ; RNA, Messenger ; analysis ; Rabbits

OBJECTIVENumerous studies in children with growth hormone deficiency (GHD) show that recombinant human growth hormone (rhGH) treatment results in significant catch-up growth, but some papers reported that the children who underwent rhGH therapy might be at increased risk of diabetes. The aim of this study was to investigate the effects of rhGH treatment on blood glucose and insulin metabolism in children with GHD and the relationship between growth hormone (GH) and glucose homeostasis.

METHODSIn this study, 44 children with GHD treated with rhGH [0.1 U/(kgxd)] and age- and sex-matched 20 healthy children were enrolled. The GHD group included 28 males and 16 females aged from 4.5 to 16.5 years (mean 10.4 +/- 2.6 years), including 18 cases of complete GHD and 26 cases of partial GHD. The sexual development stage of all subjects was in Tanner I. Oral glucose tolerance tests (OGTT) were done, and body mass index (BMI), serum insulin-like growth factor-1 (IGF-1) level and insulin resistance by homeostasis model (HOMA-IR) were measured at the time of diagnosis and every 3 months after rhGH therapy. Continuous glucose monitoring system (CGMS) was applied for two cases with hyperglycemia.

RESULTS(1) Fasting glucose and IGF-1 levels increased since 3 months of treatment and did not decrease since then. The levels of fasting glucose and IGF-1 at every time points of rhGH therapy were higher than the levels at the time of diagnosis (F = 6.81, P < 0.01; F = 7.31, P < 0.01, respectively). HOMA-IR and fasting insulin levels were increased since 3 and 9 months of treatment (P = 0.001 and P = 0.021, respectively). They decreased after 12 months of therapy and the levels at 18 months of therapy were similar to that at diagnosis. (2) Pearson correlation analysis showed that HOMA-IR was positively correlated with BMI, IGF-1 and the duration of treatment (r = 0.251, 0.437, 0.281, P < 0.01, respectively). The curve between HOMA-IR and duration of therapy was similar with parabola and the quadratic equation obtained was as follows: HOMA-IR = 1.5048 + 0.2177 x duration of therapy (months)-0.0103 x duration of therapy (months)(2) (r(2) = 0.147, F = 14.16, P < 0.01). (3) Two cases had transitory hyperglycemia. Their fasting glucose levels were all higher than 7.1 mmol/L. The glucose levels returned to normal after 1 month and 5 days respectively. OGTT and CGMS showed that their plasma glucose levels were normal after rhGH therapy was applied again.

CONCLUSIONThe children who underwent rhGH therapy may be at increased risk of insulin resistance (especially during the first year) and the therapy may even induce transitory glucose metabolic disorder in a very small proportion of patients. Circulating IGF-1 may participate in the control of insulin sensitivity and play an important role in the hormonal balance between GH and insulin. It may be necessary to monitor glucose metabolism and IGF-1 for all children who are treated with rhGH therapy.

Adolescent ; Blood Glucose ; drug effects ; metabolism ; Body Mass Index ; Case-Control Studies ; Child ; Child, Preschool ; Energy Metabolism ; drug effects ; Female ; Follow-Up Studies ; Glucose ; metabolism ; Glucose Tolerance Test ; Growth Disorders ; drug therapy ; etiology ; metabolism ; Homeostasis ; drug effects ; Human Growth Hormone ; administration & dosage ; adverse effects ; deficiency ; pharmacology ; Humans ; Hyperglycemia ; chemically induced ; Insulin ; blood ; Insulin Resistance ; Insulin-Like Growth Factor I ; analysis ; Male ; Recombinant Proteins ; pharmacology ; Time Factors ; Treatment Outcome