Association of in vitro fertilization outcome with circulating insulin-like growth factor components prior to cycle initiation

OBJECTIVE

Components of the insulin-like growth factor (IGF) system enhance in vitro embryo quality and implantation rates in both animal models and human in vitro fertilization (IVF). We evaluated whether differences in serum levels of these components in women prior to initiation of an IVF cycle would be predictive of subsequent outcome.

STUDY DESIGN

In this retrospective study sera from women obtained at day 2 of their IVF cycle (at baseline before stimulation) were assayed for IGF-I, IGF-II, and IGF binding protein (BP)-1 by enzyme-linked immunosorbent assay. Samples from 54 women with a live birth, 38 with a transient biochemical pregnancy, 45 with a spontaneous abortion, 54 who did not become pregnant, and 35 who had an ectopic pregnancy were available for analysis. Associations between the assays and outcome were evaluated by the Kruskal-Wallis test and receiver operating characteristic analysis.

RESULTS

There were no differences in the number of oocytes retrieved, oocyte quality, fertilization rates, or embryo grade between groups. Median concentrations of IGF-I were elevated in women with a live birth (29.1 ng/mL) as compared to women with a biochemical pregnancy (25.6 ng/mL), with spontaneous abortion (21.2 ng/mL), who were not pregnant (18.7 pg/mL), or who had an ectopic pregnancy (4.2 pg/mL) (P < .001). Conversely, median levels of IGF-II were reduced in women with a live birth (294.5 ng/mL) as opposed to 357.5, 393.6, 407.2, and 426.9 ng/mL in women with a biochemical pregnancy, with ectopic pregnancy, with spontaneous abortion, or who were not pregnant, respectively (P < .001). Median IGFBP-1 concentrations were markedly elevated in women with a live birth (23.6 ng/mL) compared to 18.3, 14.1, 13.8, and 9.5 ng/mL in women with a biochemical pregnancy, with spontaneous abortion, who were not pregnant, or with an ectopic pregnancy (P < .001). The combination of IGF-I and IGFBP-1 best predicted the occurrence of a live birth with an area under the curve of 0.892.

CONCLUSION

Maternal serum levels of IGF-I, IGF-II, and IGFBP-1 prior to initiation of an IVF cycle are correlated with the likelihood of a live birth. Alterations in maternal IGF system components may influence oocyte quality or the success of early postfertilization events and embryo implantation.

Carnosine decreases IGFBP1 production in db/db mice through suppression of HIF-1

IGF binding protein 1 (IGFBP1) is a member of the binding proteins for the IGF with an important role in glucose homeostasis. Circulating IGFBP1 is derived essentially from the liver where it is mainly regulated negatively by insulin. Carnosine, a natural antioxidant, has been shown to improve metabolic control in different animal models of diabetes but its mechanisms of action are still not completely unraveled. We therefore investigate the effect of carnosine treatment on the IGFBP1 regulation in db/db mice. Db/db mice and heterozygous non-diabetic mice received for 4 weeks regular water or water supplemented with carnosine. Igfbp1 mRNA expression in the liver was evaluated using qPCR and the protein levels in plasma by western blot. Plasma IGF1 and insulin were analyzed using immunoassays. HepG2 cells were used to study the in vitro effect of carnosine on IGFBP1. The modulation of hypoxia inducible factor-1 alpha (HIF-1α) which is the central mediator of hypoxia-induction of IGFBP1 was analyzed using: WB, reporter gene assay and qPCR. Carnosine decreased the circulating IGFBP1 levels and the liver expression Igfbp1, through a complex mechanism acting both directly by suppressing the HIF-1α-mediated IGFBP1 induction and indirectly through increasing circulating insulin level followed by a decrease in the blood glucose levels and increased the plasma levels or IGF1. Reduction of IGFBP1 in diabetes through insulin-dependent and insulin-independent pathways is a novel mechanism by which carnosine contributes to the improvement of the metabolic control in diabetes.

Progesterone receptor transcriptome and cistrome in decidualized human endometrial stromal cells

Decidualization is a complex process involving cellular proliferation and differentiation of the endometrial stroma that is required to establish and support pregnancy. Progesterone acting via its nuclear receptor, the progesterone receptor (PGR), is a critical regulator of decidualization and is known to interact with certain members of the activator protein-1 (AP-1) family in the regulation of transcription. In this study, we identified the cistrome and transcriptome of PGR and identified the AP-1 factors FOSL2 and JUN to be regulated by PGR and important in the decidualization process. Direct targets of PGR were identified by integrating gene expression data from RNA sequencing with the whole-genome binding profile of PGR determined by chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) in primary human endometrial stromal cells exposed to 17β-estradiol, medroxyprogesterone acetate, and cAMP to promote in vitro decidualization. Ablation of FOSL2 and JUN attenuates the induction of 2 decidual marker genes, IGFBP1 and PRL. ChIP-seq analysis of genomic binding revealed that FOSL2 is bound in proximity to 8586 distinct genes, including nearly 80% of genes bound by PGR. A comprehensive assessment of the PGR-dependent decidual transcriptome integrated with the genomic binding of PGR identified FOSL2 as a potentially important transcriptional coregulator of PGR via direct interaction with regulatory regions of genes actively regulated during decidualization.

Influence of Cancer-Associated Endometrial Stromal Cells on Hormone-Driven Endometrial Tumor Growth

Cancer-associated fibroblasts have been shown to inhibit or stimulate tumor growth depending on stage, grade, and tumor type. It remains unclear, however, the effect of endometrial-cancer-associated fibroblasts on hormone-driven responses in endometrial cancer. In this study, we investigated the effect of normal and cancer-associated stromal cells from patients with and without endometrial cancer on endometrial tumor growth in response to estradiol (E2) and progesterone (P4). Compared to benign endometrial stromal cells, the low-grade and high-grade cancer-associated stromal cells exhibited a blunted hormone response for proliferation as well as IGFBP1 secretion. Additional analysis of the influence of stromal cells on hormone-driven tumor growth was done by mixing stromal cells from benign, low-grade, or high-grade tumors, with Ishikawa cells for subcutaneous tumor formation. The presence of both benign and high-grade cancer-associated stromal cells increased estradiol-driven xenografted tumor growth compared to Ishikawa cells alone. Low-grade cancer-associated stromal cells did not significantly influence hormone-regulated tumor growth. Addition of P4 attenuated tumor growth in Ishikawa + benign or high-grade stromal cells, but not in Ishikawa cells alone or with low-grade stromal cells. Using an angiogenesis focused real-time array TGFA, TGFB2 and TGFBR1 and VEGFC were identified as potential candidates for hormone-influenced growth regulation of tumors in the presence of benign and high-grade stromal cells. In summary, endometrial-cancer-associated cells responded differently to in vitro hormone treatment compared to benign endometrial stromal cells. Additionally, presence of stromal cells differentially influenced hormone-driven xenograft growth in vivo depending on the disease status of the stromal cells.

Effects of tibolone and its metabolites on prolactin and insulin-like growth factor binding protein-1 expression in human endometrial stromal cells

The effects of the postmenopausal replacement steroid tibolone and its 3α-, 3β-OH and Δ-4 tibolone metabolites were evaluated on progesterone receptor-mediated classic decidualization markers insulin-like growth factor binding protein-1 (IGFBP-1) and prolactin expression in human endometrial stromal cells (HESCs). Supernatants of conditioned medium or erxtracted RNA from experimental cell incubations of confluent HESCs were subjected to ELISAs, Western blot analysis and RT/PCR, and results were statisically assesed. Over 21 days, specific ELISAs observed linear increases in secreted IGFBP-1 and prolactin levels elicited by tibolone and its metabolites. Cultured HESCs were refractory to E2 and dexamethasone, whereas tibolone and each metabolite exceeded medroxyprogesterone acetate in significantly elevating IGFBP-1 and prolactin output. Anti-progestins eliminated IGFBP-1 and prolactin induction by tibolone and its metabolites. Immunoblotting and RT/PCR confirmed ELISA results. These observations of IGFBP-1 and prolactin expression: (a) indicate the relevance of cultured HESCs in evaluating the chronic effects of tibolone administration to women; (b) are consistent with PR-mediated endometrial atrophy and protection against endometrial bleeding despite the persistence of circulating ER-binding, but not PR-binding metabolites following tibolone administration to women.

Data Mining of Determinants of Intrauterine Growth Retardation Revisited Using Novel Algorithms Generating Semantic Maps and Prototypical Discriminating Variable Profiles

OBJECTIVES

Intra-uterine growth retardation is often of unknown origin, and is of great interest as a "Fetal Origin of Adult Disease" has been now well recognized. We built a benchmark based upon a previously analysed data set related to Intrauterine Growth Retardation with 46 subjects described by 14 variables, related with the insulin-like growth factor system and pro-inflammatory cytokines, namely interleukin-6 and tumor necrosis factor-α.

DESIGN AND METHODS

We used new algorithms for optimal information sorting based on the combination of two neural network algorithms: Auto-contractive Map and Activation and Competition System. Auto-Contractive Map spatializes the relationships among variables or records by constructing a suitable embedding space where 'closeness' among variables or records reflects accurately their associations. The Activation and Competition System algorithm instead works as a dynamic non linear associative memory on the weight matrices of other algorithms, and is able to produce a prototypical variable profile of a given target.

RESULTS

Classical statistical analysis, proved to be unable to distinguish intrauterine growth retardation from appropriate-for-gestational age (AGA) subjects due to the high non-linearity of underlying functions. Auto-contractive map succeeded in clustering and differentiating completely the conditions under study, while Activation and Competition System allowed to develop the profile of variables which discriminated the two conditions under study better than any other previous form of attempt. In particular, Activation and Competition System showed that ppropriateness for gestational age was explained by IGF-2 relative gene expression, and by IGFBP-2 and TNF-α placental contents. IUGR instead was explained by IGF-I, IGFBP-1, IGFBP-2 and IL-6 gene expression in placenta.

CONCLUSION

This further analysis provided further insight into the placental key-players of fetal growth within the insulin-like growth factor and cytokine systems. Our previous published analysis could identify only which variables were predictive of fetal growth in general, and identified only some relationships.

[INDUCTION OF DECIDUAL DIFFERENTIATION OF ENDOMETRIAL MESENCHYMAL STEM CELLS]

In this study, we compared the ability of human mesenchymal stem cells derived from menstrual blood (eMSCs) and mesenchymal stem cells (MSCs) from other tissues to differentiate into decidual cells in vitro. It was demonstrated that during differentiation secretion of decidualization markers (prolactin and insulin-like growth factor binding protein-1) increases in eMSCs from adipose tissue (MSC-AD). Thus, the ability of eMSCs to differentiate into decidual cells is much higher than MSC-BM or MSC-AD. It makes eMSCs promising for application in cellular therapy of infertility associated with decidualzation insufficiency.

The metabolic syndrome and ECG detected left ventricular hypertrophy--influences from IGF-1 and IGF-binding protein-1

Background and Aims

The metabolic syndrome (MetS) is associated with an increased risk for left ventricular hypertrophy (LVH) and cardiovascular mortality. The aim of this study was to investigate potential influences from insulin-like growth factor-1 (IGF-1) and IGF binding protein-1 (IGFBP-1) on the relationship between the MetS and LVH, also taking into account the role of physical activity (PA), use of oestrogen and gender.

Methods and Results

In a population-based cross-sectional study of 60-year-old men (n = 1822) and women (n = 2049) participants underwent physical examination and laboratory tests, including electrocardiography (ECG), and completed an extensive questionnaire. Women showed higher levels of IGFBP-1 than men (37.0 vs. 28.0 µg/l, p<0.001), and women with LVH had lower levels of IGFBP-1 than women without LVH (31.0 µg/l vs. 37.0 µg/l, p<0.001). Furthermore, women with low levels of IGFBP-1 had a significantly increased risk of having LVH (crude OR≈2.5). When stratifying for PA and oestrogen, respectively, a weaker association between IGFBP-1 and LVH was demonstrated in physically active men and women, compared to inactive individuals, as well as in women using oestrogen, compared to non-users.

Conclusion

In a representative sample of 60-year-old Swedish men and women, the main findings were higher levels of IGFBP-1 in women than in men; lower levels of IGFBP-1 in women with LVH, compared to women without LVH; and an increased risk of having LVH in women with low levels of IGFBP-1. The association between IGFBP-1 and LVH was diminished in physically active men and women, as well as in women using oestrogen.

Comparison of placental alpha microglobulin-1 in vaginal fluid with intra-amniotic injection of indigo carmine for the diagnosis of rupture of membranes

AIMS

The purpose of this study was to compare the diagnostic performance of an immunoassay for placental alpha microglobulin-1 (PAMG-1) in vaginal fluid with the intra-amniotic instillation of indigo carmine for the diagnosis of membrane rupture in patients with an equivocal status.

METHODS

A prospective multi-site study was performed involving women reporting signs, symptoms, or complaints suggestive of rupture of membrane (ROM) between 21 and 42 weeks of gestation without obvious leakage of fluid from the cervical os during sterile speculum examination and without confirmation of ROM by traditional methods.

RESULTS

A total of 140 patients were recruited with a prevalence of ROM of 19.3%. The PAMG-1 test had a sensitivity of 100.0% [confidence interval (CI) 0.87-1.0], specificity of 99.1% [(CI) 0.95-0.99], positive predictive value of 96.3% [(CI) 0.82-0.99], negative predictive value of 100.0% [(CI) 0.97-1.0], and ± likelihood ratios of 74.6 [(CI) 20.31-274.51] and 0.0 [(CI) 0.00-0.98].

CONCLUSIONS

The PAMG-1 immunoassay in vaginal fluid yielded results that were comparable to those of the instillation of indigo carmine into the amniotic cavity; therefore, we propose that PAMG-1 is a sensitive and specific test to assess ROM in patients with an equivocal diagnosis based on simple tests. This finding prompts consideration for the use of the noninvasive PAMG-1 test in situations where the use of the invasive dye test is not practical.

Insulin-like growth factor binding protein-1 inhibits cancer cell invasion and is associated with poor prognosis in hepatocellular carcinoma

Insulin-like growth factor binding protein-1 (IGFBP-1) plays an important role in the development and progression of cancer. However, the expression of IGFBP-1 remains equivocal, and little is known about its clinicopathological significance and prognostic value in hepatocellular carcinoma (HCC). In this study, we evaluated the expression of IGFBP-1 in 90 paired HCC tissues and adjacent non-cancerous liver tissues and analyzed its clinical and prognostic significance. The results showed that IGFBP-1 was detected in cytoplasm as well as cell nucleus, and down-regulated in HCC tissues compared to the adjacent non-cancerous liver tissues. The decreased expression of IGFBP-1 was correlated with tumor differentiation, liver cirrhosis, microvascular invasion or metastasis, TNM stage and poor survival. Moreover, low levels of IGFBP-1 may be an independent prognostic indicator for the survival of patients with HCC. We also evaluated its function by adding recombinant IGFBP-1 to the cultured HCC cell lines HepG2 and MHCC97-H. The result of the invasion chamber assay showed that IGFBP-1 could inhibit the invasion of HepG2 and MHCC97-H. MMP-9 secretion by these cells was significantly decreased when the cells were treated with IGFBP-1. Our results suggest that IGFBP-1 inhibits the invasion and metastasis of HCC cells and that IGFBP-1 may be useful as a valuable marker for the prognosis of patients with HCC.

Lysophosphatidic acid enhanced the angiogenic capability of human chondrocytes by regulating Gi/NF-kB-dependent angiogenic factor expression

Lysophosphatidic acid (LPA) has been found to mediate myeloid differentiation, stimulate osteogenesis, alter cell proliferation and migration, and inhibit apoptosis in chondrocytes. The effect of LPA on the angiogenic capability of chondrocytes is not clear. This study aimed to investigate its effect on the angiogenic capability of human chondrocytes and the underlying mechanism of these effects. Human chondrocyte cell line, CHON-001, commercialized human chondrocytes (HC) derived from normal human articular cartilage, and human vascular endothelial cells (HUVECs) were used as cell models in this study. The angiogenic capability of chondrocytes was determined by capillary tube formation, monolayer permeability, cell migration, and cell proliferation. An angiogenesis protein array kit was used to evaluate the secretion of angiogenic factors in conditioned medium. Angiogenin, insulin-like growth factor-binding protein 1 (IGFBP-1), interleukin (IL)-8, monocyte chemoattractant protein-1 (MCP-1), matrix metalloproteinase (MMP)-9, and vascular endothelial growth factor (VEGF) mRNA and protein expressions were evaluated by Q-RT-PCR and EIA, respectively. LPA receptor (LPAR) expression was determined by RT-PCR. Signaling pathways were clarified using inhibitors, Western blot analysis, and reporter assays. The LPA treatment promoted the angiogenic capability of CHON-001 cells and HC, resulting in enhanced HUVEC capillary tube formation, monolayer permeability, migration, and cell growth. Angiogenin, IGFBP-1, IL-8, MCP-1, MMP-9, and VEGF mRNA and protein expressions were significantly enhanced in LPA-treated chondrocytes. LPA2, 3, 4 and 6 were expressed in CHON-001 and HC cells. Pretreatment with the Gi/o type G protein inhibitor, pertussis toxin (PTX), and the NF-kB inhibitor, PDTC, significantly inhibited LPA-induced angiogenin, IGFBP-1, IL-8, MCP-1, MMP-9, and VEGF expressions in chondrocytes. The PTX pretreatment also inhibited LPA-mediated NF-kB activation, suggesting the presence of active Gi/NF-kB signaling in CHON-001 and HC cells. The effect of LPA on the angiogenesis-inducing capacity of chondrocytes may be due to the increased angiogenesis factor expression via the Gi/NF-kB signaling pathway.

Placental alkaline phosphatase de-phosphorylates insulin-like growth factor (IGF)-binding protein-1

BACKGROUND

Insulin-like growth factors (IGF) regulate fetal growth through their effects on placenta. Their actions are influenced by IGF binding protein-1. Phosphorylated IGFBP-1 (pIGFBP-1) has high affinity for IGF-I and usually inhibits IGF-I activity but during pregnancy, it is de-phosphorylated to generate lower affinity isoforms and consequently, increased IGF bioavailability. Here we investigate the role of placenta in this process.

RESULTS

Our data show that term human placental explants, but not their conditioned medium, can de-phosphorylate IGFBP-1 through the action of placental alkaline phosphatase (PLAP).

DISCUSSION

PLAP-mediated de-phosphorylation of IGFBP-1 may provide a mechanism for controlling IGF-I bioavailability and action at the maternal/fetal interface.

IGF binding proteins in cancer: mechanistic and clinical insights

The six members of the family of insulin-like growth factor (IGF) binding proteins (IGFBPs) were originally characterized as passive reservoirs of circulating IGFs, but they are now understood to have many actions beyond their endocrine role in IGF transport. IGFBPs also function in the pericellular and intracellular compartments to regulate cell growth and survival - they interact with many proteins, in addition to their canonical ligands IGF-I and IGF-II. Intranuclear roles of IGFBPs in transcriptional regulation, induction of apoptosis and DNA damage repair point to their intimate involvement in tumour development, progression and resistance to treatment. Tissue or circulating IGFBPs might also be useful as prognostic biomarkers.

Impaired postprandial response of the insulin-like growth factor system in maintenance haemodialysis

OBJECTIVE

Patients on maintenance haemodialysis (HD) have reduced circulating free and bioactive insulin-like growth factor I (IGF-I) due to increased IGF-binding proteins (IGFBPs). This study investigated the postprandial response of the IGF system in HD patients compared with matched healthy subjects.

DESIGN AND PATIENTS

In a crossover study, twelve nondiabetic HD patients were assigned in a random order to three 10-h study days: (1) a non-HD day with one meal served at baseline (NHDM1), (2) an HD day with one meal served during HD (HDM1) and (3) an HD day with two meals served during and after HD, respectively (HDM2). Twelve healthy controls conducted session 1.

RESULTS

After the baseline meal, insulin concentrations changed similarly in HD patients and controls, whereas hyperglycaemia was more prolonged in HD patients (P < 0·001). Postprandial IGFBP-1 showed greater reductions from baseline in controls (-76% [-81; -70%], mean [95% confidence intervals], P < 0·001) than in patients on non-HD days (-45% [-57; -30%], P < 0·001). In the latter group, the response was even more attenuated during HD (-22% [-38; -1%] and -24% [-40; -4%], P ≤ 0·041). After the second meal on HDM2 days, IGFBP-1 further decreased (-50% [-61; -37%], P < 0·001), whereas IGFBP-1 returned to baseline levels on the other study days. Consistently, at the end of the study days, bioactive IGF-I was significantly above baseline only on HDM2 days (+22% [+5; +43%], P = 0·012).

CONCLUSIONS

HD patients were unable to suppress IGFBP-1 to the same extent as healthy controls, which may increase the risk of protein-energy wasting in maintenance HD. A second meal after HD, however, effectively suppressed IGFBP-1 and increased bioactive IGF-I.

Relationship between use of proton pump inhibitors and IGF system in older subjects

OBJECTIVES

to investigate the effects of proton pump inhibitors (PPIs) on the insulin-like-growth factor 1(IGF-1) system in the elderly.

DESIGN

cross-sectional.

SETTING

InCHIANTI study.

PARTICIPANTS

938 older subjects (536 women, 402 men, mean age 75.7±7.4 years).

MEASUREMENTS

complete data on age, sex, BMI, liver function, medications, dietary intake, IGF-1, IGF-binding protein-1 and -3 (IGFBP-1, IGFBP-3).

RESULTS

Participants were categorized by PPI use, identifying 903 PPI non users and 35 users. After adjusting for age, male PPI users (107.0 ± 69.6 vs. 127.1 ± 55.8, p<0.001) and female PPI users (87.6 ± 29.1 vs. 107.6 ± 52.3, p=0.03) had lower IGF-1 levels than non-users. IGFBP-1 levels were similar in the two groups in both sexes. In whole population, after adjustment for age and sex, PPI users had lower IGF-1 levels 81.9 [61.1-113.8] than non-users 110 [77.8-148.6], p=0.02. After further adjustment for BMI, albumin, liver function, C-reactive protein, Interleukin-6, number of medications, ACE-inhibitors use, caloric intake, protein intake, physical activity, glycemia, and IGFBP-1, the use of PPIs remained significantly and negatively associated with IGF-1 levels (β±SE = -19.60±9.83, p=0.045).

CONCLUSION

Use of PPIs was independently and negatively associated with IGF-1 levels.

Liver mTOR controls IGF-I bioavailability by regulation of protein kinase CK2 and IGFBP-1 phosphorylation in fetal growth restriction

Fetal growth restriction (FGR) increases the risk for perinatal complications and predisposes the infant to diabetes and cardiovascular disease later in life. No treatment for FGR is available, and the underlying pathophysiology remains poorly understood. Increased IGFBP-1 phosphorylation has been implicated as an important mechanism by which fetal growth is reduced. However, to what extent circulating IGFBP-1 is phosphorylated in FGR is unknown, and the molecular mechanisms linking FGR to IGFBP-1 phosphorylation have not been established. We used umbilical cord plasma of appropriate for gestational age (AGA) and growth-restricted human fetuses and determined IGFBP-1 and IGF-I concentrations (ELISA) and site-specific IGFBP-1 phosphorylation (Western blotting using IGFBP-1 phospho-site specific antibodies). In addition, we used a baboon model of FGR produced by 30% maternal nutrient restriction and determined mammalian target of rapamycin (mTOR)C1 activity, CK2 expression/activity, IGFBP-1 expression and phosphorylation, and IGF-I levels in baboon fetal liver by Western blot, enzymatic assay, and ELISA. HepG2 cells and primary fetal baboon hepatocytes were used to explore mechanistic links between mTORC1 signaling and IGFBP-1 phosphorylation. IGFBP-1 was hyperphosphorylated at Ser101, Ser119, and Ser169 in umbilical plasma of human FGR fetuses. IGFBP-1 was also hyperphosphorylated at Ser101, Ser119, and Ser169 in the liver of growth-restricted baboon fetus. mTOR signaling was markedly inhibited, whereas expression and activity of CK2 was increased in growth-restricted baboon fetal liver in vivo. Using HepG2 cells and primary fetal baboon hepatocytes, we established a mechanistic link between mTOR inhibition, CK2 activation, IGFBP-1 hyperphosphorylation, and decreased IGF-I-induced IGF-I receptor autophosphorylation. We provide clear evidence for IGFBP-1 hyperphosphorylation in FGR and identified an mTOR and CK2-mediated mechanism for regulation of IGF-I bioavailability. Our findings are consistent with the model that inhibition of mTOR in the fetal liver, resulting in increased CK2 activity and IGFBP-1 hyperphosphorylation, constitutes a novel mechanistic link between nutrient deprivation and restricted fetal growth.

Functional differentiation of spider hemocytes by light and transmission electron microscopy, and MALDI-MS-imaging

The most abundant cell types in the hemolymph of Cupiennius salei are plasmatocytes (70-80%) and granulocytes (20-30%). Both cells differ in shape, cytochemical and transmission electron microscopy staining of their cytoplasma and granules. According to MALDI-IMS (matrix-assisted laser desorption ionisation-mass spectrometry imaging), granulocytes exhibit ctenidin 1 (9510 Da) and ctenidin 3 (9568 Da), SIBD-1 (8675 Da), and unknown peptides with masses of 2207 and 6239 Da. Plasmatocytes exhibit mainly a mass of 6908 Da. Unknown peptides with masses of 1546 and 1960 Da were detected in plasmatocytes and granulocytes. Transmission electron microscopy confirms the presence of two compounds in one granule and cytochemical staining (light microscopy) tends to support this view. Two further hemocyte types (cyanocytes containing hemocyanin and prehemocytes as stem cells) are only rarely detected in the hemolymph. These four hemocyte types constitute the cellular part of the spider immune system and this is discussed in view of arachnid hemocyte evolution.

Possible roles of insulin, IGF-1 and IGFBPs in initiation and progression of colorectal cancer

AIM: To investigate the roles of serum insulin, insulin-like growth factor-1 (IGF-1), and insulin-like growth factor binding proteins (IGFBPs) in the initiation and progression of colorectal cancer.

METHODS: We determined serum insulin, IGF-1 and IGFBPs levels in 615 colorectal cancer patients and 650 control healthy donors by enzyme-linked immunosorbent assay (ELISA). In the meantime, their body mass index (BMI) and waist-to-hip ratio (WHR) were measured.

RESULTS: Serum levels of insulin and IGF-1 as well as IGF-1/IGFBP-3 ratio in pre-operation patients were significantly elevated, but the level of IGFBP-3 was significantly decreased compared with normal controls and post-operation patients (P < 0.05 and P < 0.001, respectively). There is no significant difference (P > 0.05) in the levels of insulin, IGF-1, IGFBP-1, IGFBP-3 and IGF-1/IGFBP-3 between the patients with and without hepatic as well as distal abdominal metastases. WHR and BMI of colon cancer patients were positively and significantly correlated with the levels of insulin and IGF-1/IGFBP-3. In contrast, WHR and BMI were negatively correlated with IGFBP-3 level.

CONCLUSION: The elevation of insulin, IGF-1 as well as IGF-1/IGFBP-3 ratio and the reduction of IGFBP-3 may be related to the initiation of colorectal cancer, but they are not related to the progression and outcome of the disease.

The role of exchange protein directly activated by cyclic AMP 2-mediated calreticulin expression in the decidualization of human endometrial stromal cells

Decidualization of human endometrial stromal cells (ESCs) accompanied by the production of prolactin (PRL) and IGF-binding protein (IGFBP) 1 and rounded-cell morphology is indispensable for the establishment and maintenance of pregnancy. Protein kinase A (PKA)-mediated cAMP signaling is known to be crucial for decidualization. We previously reported that activation of a cAMP mediator, called Exchange protein directly activated by cAMP (EPAC) promotes cAMP analog- or ovarian steroid-induced decidualization in cultured human ESCs. In addition, small interfering RNA-mediated knock-down of the EPAC subtypes, EPAC1 or EPAC2, or knock-down of Rap1, a downstream factor of EPAC signaling, blocked functional and morphological decidualization of ESCs. However, factors downstream of EPAC2 other than Rap1 have not been determined. The present study was undertaken to identify additional downstream targets of EPAC2 associated with decidualization. Using proteomic analysis, we identified calreticulin (CRT) as a potential target of EPAC2. Knock-down of CRT expression in cultured ESCs significantly inhibited PKA-selective cAMP analog- or PKA-selective cAMP analog plus EPAC-selective cAMP analog-induced PRL and IGFBP1 expression. Furthermore, CRT knock-down suppressed the ovarian steroid-stimulated PRL and IGFBP1 expression and morphological differentiation, and silencing of EPAC2 or CRT significantly increased senescence-associated β-galactosidase activity with enhanced p21 expression and decreased p53 expression. These results suggest that EPAC2 and CRT are associated with cellular senescence in ESCs. In conclusion, we demonstrate here that EPAC2-mediated CRT expression is essential for the functional and morphological differentiation of ESCs into decidual cells. Furthermore, both EPAC2 and CRT might prevent ESCs from undergoing abnormal cellular senescence during decidualization.

Importance of C/EBPβ binding and histone acetylation status in the promoter regions for induction of IGFBP-1, PRL, and Mn-SOD by cAMP in human endometrial stromal cells

Dynamic changes of gene expressions occur in human endometrial stromal cells (ESCs) during decidualization. CCAAT/enhancer-binding proteinβ (C/EBPβ) regulates the expression of a number of decidualization-related genes. In addition to transcription factors, it is important to know the role of epigenetic mechanisms, such as histone modifications in the regulation of decidualization-related genes. This study investigated the molecular and epigenetic mechanisms by which cAMP up-regulates the expression of IGF-binding protein-1 (IGFBP-1), prolactin (PRL), and manganese superoxide dismutase (Mn-SOD) in ESC. ESCs isolated from proliferative phase endometrium were incubated with cAMP to induce decidualization. IGFBP-1, PRL, and Mn-SOD mRNA expressions were determined by real-time RT-PCR. The C/EBPβ binding and histone modification status (acetylation of histone-H3 lysine-27 [H3K27ac]) in the promoter were examined by chromatin immunoprecipitation assay. Knockdowns of C/EBPβ were performed using the small interfering RNA method. cAMP induced mRNA expressions of IGFBP-1 and PRL accompanied by the increases in both C/EBPβ binding activities and H3K27ac levels in the promoters. The stimulatory effects of cAMP on mRNA levels and H3K27ac levels were completely abolished by C/EBPβ knockdown. cAMP increased Mn-SOD mRNA levels and C/EBPβ binding activities in the enhancer region. C/EBPβ knockdown inhibited Mn-SOD mRNA levels. The H3K27ac levels in the enhancer were high before cAMP stimulus but were not further increased by cAMP and were not inhibited by C/EBPβ knockdown. These results show that C/EBPβ regulates the expression of IGFBP-1 and PRL by altering the histone acetylation status of their promoters but differently regulates Mn-SOD gene expression in human ESC during decidualization.

Metabolic endocrine factors involved in spawning recovery and rematuration of iteroparous female rainbow trout (Oncorhynchus mykiss)

To determine how energy balance affects metabolic hormones hypothesized to play a role in the onset of a new reproductive cycle in iteroparous salmonids, food availability after spawning was restricted in female rainbow trout. These fish were compared with a control group that was fed a standard brood stock ration. Bodyweight, length, and muscle lipid content were determined, and blood was collected from fish at regular intervals; a subset of fish from each group was sacrificed at each sampling time for the collection of liver and ovary tissue, and to calculate hepatosomatic index (HSI) and gonadosomatic index (GSI). Plasma hormone levels were quantified by radioimmunoassay, and tissue gene expression levels were analyzed using q-RT-PCR. The experiment was conducted twice, using two-year-old and three-year-old post-spawned fish. Food-restriction arrested ovarian growth and development within 15-20 weeks, as evidenced by lower GSI in restricted-ration fish. Food restriction also reduced Fulton's condition factor, muscle lipid content, and specific growth rate from one month onward, and reduced HSI after 3 months. In the liver, insulin-like growth factor (igf1 and igf2) gene expression was reduced in three-year-old food-restricted fish within 2 months; however, no effect of ration on igf1 or igf2 expression was detected in two-year-old fish. In both years, IGF binding protein-1 (igfbp1) gene expression decreased over time in both treatment groups. Liver leptin (slepA1) gene expression was lower in two-year-old food-restricted fish at 4 months. These results show that this feed restriction regime arrested reproductive development and affected factors associated with energy balance purported to play a role in initiating reproductive development within 2-4months after spawning.

Extracellular signal-regulated kinase 1/2 signaling pathway is required for endometrial decidualization in mice and human

Decidualization is a crucial change required for successful embryo implantation and the maintenance of pregnancy. During this process, endometrial stromal cells differentiate into decidual cells in response to the ovarian steroid hormones of early pregnancy. Extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) are known to regulate cell proliferation and apoptosis in multiple cell types, including uterine endometrial cells. Aberrant activation of ERK1/2 has recently been implicated in the pathological processes of endometriosis and endometrial cancer. However, the function of ERK1/2 signaling during implantation and decidualization is still unknown. To determine the role and regulation of ERK1/2 signaling during implantation and decidualization, we examine ERK1/2 signaling in the mouse uterus during early pregnancy using immunostaining and qPCR. Interestingly, levels of phospho-ERK1/2 were highest within decidual cells located at the implantation sites. Expression levels of ERK1/2 target genes were also significantly higher at implantation sites, when compared to either inter-implantation sites. To determine if ERK1/2 signaling is also important during human endometrial decidualization, we examined levels of phospho-ERK1/2 in cultured human endometrial stromal cells during in vitro decidualization. Following treatment with a well-established decidualization-inducing steroidogenic cocktail, levels of phospho-ERK1/2 were markedly increased. Treatment with the ERK1/2 inhibitor, U0126, significantly decreased the expression of the known decidualization marker genes, IGFBP1 and PRL as well as inhibited the induction of known ERK1/2 target genes; FOS, MSK1, STAT1, and STAT3. Interestingly, the phosphorylation level of CCAAT/ enhancer binding protein β (C/EBPβ), a protein previously shown to be critical for decidualization, was significantly reduced in this model. These results suggest that ERK1/2 signaling is required for successful decidualization in mice as well as human endometrial stromal cells and implicates C/EBPβ as a downstream target of ERK1/2.

Distinct post-transcriptional regulation of Igfbp1 gene by hypoxia in lowland mouse and Qinghai-Tibet plateau root vole Microtus oeconomus

Our previous study revealed the particular expression patterns of insulin-like growth factor 1 (IGF1) and insulin-like growth factor binding protein 1 (IGFBP1) in the Qinghai-Tibet plateau root vole (Microtus oeconomus) under hypoxic challenge. Here we report the molecular mechanisms of Igf gene regulation associated with adaptation to hypoxia. M. oeconomus IGF1 and IGFBP1 were shown to be highly conserved. Hypoxia (8.0% O2, 6h) did not change the liver-derived Igf1 expression in either M. oeconomus or mouse. Hypoxia significantly upregulated hepatic Igfbp1 gene expression and IGFBP1 levels in the liver and plasma of the mouse, but not in M. oeconomus. A functional U-rich element in the 3' untranslated region was found in mouse Igfbp1 mRNA, which was associated with Igfbp1 mRNA stabilization and upregulation under hypoxia, and this U-rich element was eliminated in the M. oeconomus Igfbp1, resulting in blunted Igfbp1 mRNA upregulation, which might be understood as a sequence variation modified during molecular evolution under hypoxia.

Associations of insulin-like growth factor-I and its binding proteins and testosterone with frailty in older men

OBJECTIVE

Ageing is associated with frailty and decreased anabolic hormones, insulin-like growth factor-I (IGF-I) and testosterone. We hypothesized that components of the IGF-I system, in conjunction with testosterone, modulate frailty risk in the elderly. We examined associations between IGF-I, its binding proteins IGFBP1 and IGFBP3 and testosterone with frailty in men.

DESIGN

Observational study of 3 447 community-dwelling men aged 70-89 years assessed in 2001-04, with 1 654 reassessed in 2008-09.

METHODS

Baseline total IGF-I, IGFBP1, IGFBP3 and testosterone were assayed. Frailty was assessed using the FRAIL scale, comprising 5 domains: fatigue; difficulty climbing stairs; difficulty walking >100 m; >5 illnesses; weight loss >5%. Men with ≥ 3 domains were considered frail.

RESULTS

At baseline, 527 men (15·3%) were frail. Frail men had lower IGFBP3 (3 630 ng/ml vs not frail: 3 800 ng/ml, P < 0·001) and comparable IGFBP1 (23·5 vs 21·5 ng/ml, P = 0·09). In multivariate analyses, higher IGFBP1 was associated with increased prevalence of frailty (highest vs lowest quartile Q4:Q1, adjusted odds ratio [OR] = 1·39, 95% CI = 1·03-1·88). New-onset frailty arose in 260 (17·5%) of 1 484 men. Lower baseline IGF-I predicted new-onset frailty (Q1:Q4 OR = 1·48, 95% CI = 1·00-2·20) as did higher IGFBP1 (Q4:Q1 OR = 1·59, 95% CI = 1·01-2·50). Men with both IGF-I and free testosterone in Q1 had greater odds of prevalent frailty (OR = 2·13, 95% CI = 1·54-2·95).

CONCLUSIONS

Older men with higher IGFBP1 level, or both lower IGF-I and testosterone, are more likely to be frail, while those with lower IGF-I and higher IGFBP1 are more likely to become frail. Components of the IGF-I system may be biomarkers or independent predictors of frailty.

Effect of cyclic AMP and estrogen/progesterone on the transcription of DNA methyltransferases during the decidualization of human endometrial stromal cells

Progesterone, estrogen and cyclic adenosine monophosphate (cAMP) together regulate the decidualization of human endometrial stromal cells in a time-dependent manner. The role of DNA methylation and the three active DNA methyltransferases (DNMTs) in the regulation of decidualization is gaining interest but the exact role of this epigenetic mechanism during decidualization is largely unknown. We aimed to understand the effect of the main regulators of decidualization on the expression of the DNMTs and in turn on the expression of steroid hormone receptors during the decidualization. We conducted a time-course analysis from 6 h to 10 days to examine the change in gene expression of the DNMTs and the steroid hormone receptors over time in response to estradiol, medroxy-progesterone acetate (MPA) and dibutyryl-cAMP (db-cAMP) in a human endometrial stromal cells (HESC) cell line. Only the combination treatment with MPA-mix (estradiol + MPA + db-cAMP) up-regulated ERα, PGR, progesterone receptor B (PRB) and androgen receptor at 24 h. Both decidualization pathways of db-cAMP and estradiol/MPA, independently and combined, consistently down-regulated DNMT3B mRNA expression from 6 h till 10 days, whereas DNMT1 and DNMT3A mRNA expression were down-regulated transiently. Forced expression of DNMT3B in HESC for 10 days attenuated IGFBP1 mRNA and protein expression; and forced expression of DNMT3B combined with MPA-mix treatment synergistically increased the expression of PRB at 24 h. The HESC morphology and proliferation remained unchanged in response to forced expression of DNMT3B. In conclusion, mRNA expression of the DNMTs during decidualization is dynamic, so that expression varies according to the cAMP or estradiol/MPA pathway treatments that regulate them in a time-dependent manner. Although forced expression of DNMT3B by itself is insufficient to inhibit decidualization, forced expression of DNMT3B in combination with MPA-mix synergistically up-regulated PRB, as well as attenuated the expression of IGFBP1, the decidualization marker.