Regional Handling and Prognostic Performance of Circulating Insulin-Like Growth Factor Binding Protein-7 in Heart Failure.

BACKGROUND: Regional handling and the prognostic performance of insulin-like growth factor binding protein (IGFBP)-7, in contrast or in combination with other candidate biomarkers, in chronic heart failure (CHF) remain uncertain. OBJECTIVES: The authors investigated the regional handling of plasma IGFBP-7 and its association with long-term outcomes in CHF in comparison with selected circulating biomarkers. METHODS: Plasma concentrations of IGFBP-7, N-terminal pro-B-type natriuretic peptide (NT-proBNP), high-sensitivity troponin-T, growth differentiation factor-15, and high-sensitivity C-reactive protein were measured prospectively in a cohort with CHF (n = 863). The primary outcome was the composite of heart failure (HF) hospitalization or all-cause mortality. In a separate non-HF cohort (n = 66) undergoing cardiac catheterization, transorgan gradients of plasma IGFBP-7 concentrations were evaluated. RESULTS: Among 863 patients (age 69 ± 14 years, 30% female, 36% HF with preserved ejection fraction), IGFBP-7 (median: 121 [IQR: 99-156] ng/mL) related inversely to left ventricular volumes but directly to diastolic function. Above the optimal cutoff, IGFBP-7 ≥110 ng/mL was independently associated with 32% increased hazard of the primary outcome: 1.32 (95% CI: 1.06-1.64). Among the 5 markers, IGFBP-7 had the highest hazard for a proportional increment in plasma concentrations independent of HF phenotype in single- and double-biomarker models, and provided incremental prognostic value beyond clinical predictors plus NT-proBNP, high-sensitivity troponin-T, and high-sensitivity C-reactive protein (P < 0.05). Assessment of regional concentrations indicated renal secretion of IGFBP-7 in contrast to renal extraction of NT-proBNP, possible cardiac extraction of IGFBP-7 in contrast to secretion of NT-proBNP, and common hepatic extraction of both peptides. CONCLUSIONS: Transorgan regulation of IGFBP-7 is distinct from NT-proBNP. Circulating IGFBP-7 independently predicts adverse outcomes in CHF with a strong prognostic performance when compared with other well-recognized cardiac-specific or noncardiac prognostic markers.

IGFBPs were associated with stemness, inflammation, extracellular matrix remodeling and poor prognosis of low-grade glioma.

Background: The IGFBP family of insulin-like growth factor binding proteins has important biological functions in the organism. However, the role of the IGFBP family in low-grade glioma (LGG) has not been fully explored. Methods: We validated the clinical value of the IGFBP family using RNA-seq and clinical data of LGG in the TCGA and constructed an IGFBPScore using LASSO-regression analysis for prognosis prediction, subtype determination, and treatment sensitivity determination. Subsequently, we explored the role of the IGFBP family in the development of LGG using PanCanAtlas data. Results: Our results suggest that most IGFBP family members were aberrantly expressed and were strongly associated with poor prognosis in LGG. By constructing an IGFBPScore representing the IGFBP family, we found that tumor samples with a high IGFBPScore had a glioblastoma-like mutation pattern characterized by IDH1wt, EGFRmut, PTENmut, and NF1mut with hypo-methylation and glioma stem cell (GSC) diversity. In contrast, the low IGFBPScore group was characterized by IDH1mut accompanied by TP53mut, CICmut, and ATRXmut, and had hyper-methylation status as well as the GSC restriction. Additionally, the high-IGFBPScore group had a high inflammation phenotype with increased immune antigenicity and increased infiltration of immune molecules and cells, as well as a high extracellular matrix phenotype and enhanced multiple metabolic pathways compared with the immune-quiet phenotype of the low-IGFBPScore group, which was strongly associated with poor prognosis. Conclusion: Our study provides a summary analysis and a theoretical basis for the biological role and clinical value of the IGFBP family in LGG, providing an important therapeutic target for LGG.

IGF research 2016-2018.

This article is based on my presentation at the 9th International Congress of the Growth Hormone Research and Insulin-like Growth Factor (IGF) Societies at Seattle, USA on 17th, September 2018. In the article, after a general introduction to IGF research, I briefly review the IGF research being published from 2016 to 2018, focusing on what I believe represent the most interesting areas of progress. These areas include ligands of the IGF-I receptor, ligand binding to the IGF-I receptor, long-term signaling through the IGF-I receptor, intracellular organelles where IGF signals are transmitted, and novel functions of the IGFBPs. Lastly, I discuss future directions of IGF research from my point of view.

Understanding Insulin Endocrinology in Decapod Crustacea: Molecular Modelling Characterization of an Insulin-Binding Protein and Insulin-Like Peptides in the Eastern Spiny Lobster, Sagmariasus verreauxi.

The insulin signalling system is one of the most conserved endocrine systems of Animalia from mollusc to man. In decapod Crustacea, such as the Eastern spiny lobster, Sagmariasus verreauxi (Sv) and the red-claw crayfish, Cherax quadricarinatus (Cq), insulin endocrinology governs male sexual differentiation through the action of a male-specific, insulin-like androgenic gland peptide (IAG). To understand the bioactivity of IAG it is necessary to consider its bio-regulators such as the insulin-like growth factor binding protein (IGFBP). This work has employed various molecular modelling approaches to represent S. verreauxi IGFBP and IAG, along with additional Sv-ILP ligands, in order to characterise their binding interactions. Firstly, we present Sv- and Cq-ILP2: neuroendocrine factors that share closest homology with Drosophila ILP8 (Dilp8). We then describe the binding interaction of the N-terminal domain of Sv-IGFBP and each ILP through a synergy of computational analyses. In-depth interaction mapping and computational alanine scanning of IGFBP_N' highlight the conserved involvement of the hotspot residues Q67, G70, D71, S72, G91, G92, T93 and D94. The significance of the negatively charged residues D71 and D94 was then further exemplified by structural electrostatics. The functional importance of the negative surface charge of IGFBP is exemplified in the complementary electropositive charge on the reciprocal binding interface of all three ILP ligands. When examined, this electrostatic complementarity is the inverse of vertebrate homologues; such physicochemical divergences elucidate towards ligand-binding specificity between Phyla.

Comparison of rapid immunoassays for rupture of fetal membranes.

BACKGROUND: Rupture of membranes (ROM) before the onset of uterine contractions, particularly in pregnancies less than 37 weeks gestational age, is a common diagnostic problem in obstetrical practice. Timely detection of ROM is vital to support gestational age-specific interventions to optimize perinatal outcomes and minimize the risk of serious complications such as preterm delivery, fetal distress and maternal/fetal infections. Rapid bedside immunoassay tests designed to detect amniotic fluid proteins in cervicovaginal fluids have emerged as valuable clinical tools to provide timely ROM diagnosis. METHODS: In this prospective observational study, two commercially-available immunoassay tests (ROM Plus®, AmniSure®) were evaluated concurrently in 111 pregnant women who presented with the chief complaint of ROM. Immunoassay results were compared to clinical parameters for determining ROM via comprehensive, retrospective clinical chart review. Diagnostic performance characteristics were calculated including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy. RESULTS: Overall, diagnostic performance characteristics were robust and similar between ROM Plus® and AmniSure®, respectively: sensitivity (96.4 and 89.3%), specificity (98.8 and 100%), PPV (96.4 and 100%), NPV (98.8% and 96.5) and accuracy (98.2 and 97.3%). For term patients (≥37 weeks gestation), the sensitivities were 93.8 and 81.3% and specificities were 97.1 and 100% for ROM Plus® and AmniSure®, respectively. For preterm patients (<37 weeks gestation), both immunoassay tests provided exact concordance with clinical confirmation of ROM resulting in 100% diagnostic accuracy. CONCLUSIONS: Both rapid immunoassay tests provided similarly excellent diagnostic accuracy for the rapid detection of ROM with only two discrepant results for ROM Plus® and three discrepant results for AmniSure® compared to clinical confirmation. The findings from this study recommend these tests for pregnant women presenting with suspected ROM to guide correct clinical management decisions to improve obstetrical and neonatal outcomes. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02208011 (1 August 2014).

Synovial chondromatosis of the temporomandibular joint: Immunohistochemical examinations regarding the role of insulin-like growth factors and their binding proteins in the etiology of this disease.

Synovial chondromatosis (SC) is a benign disease of the joints without a known cause. It sometimes affects the temporomandibular joint (TMJ) and is accompanied by pain, swelling, malocclusion, and crepitation. It has been divided into three stages by Milgram and is supposed to originate from the synovia and cartilage of a joint (Milgram, 1977b). The aim of this study was to examine an involvement of the insulin-like growth factors (IGF-I/-II) and their binding proteins (IGFBP-1 to -6) in the etiology of this disease. Therefore 23 specimen of SC from 16 patients were immunohistochemically stained and microscopically examined. Staining was assessed semiquantitatively: negative (-), weakly positive ((+)), moderately positive (+), strongly positive (++) and very strongly positive (+++). It could be seen that especially the chondro- and fibrocytes and the synovia showed positive staining for almost all IGFs and IGFBPs. The underlying tissue, consisting of connective tissue or chondroid matrix, was stained as well but more weakly so. We conclude that the IGF/IGFBP system seems to contribute to the pathogenesis of SC, especially IGF-I and -II, and their effects enhancing binding protein 5.

PAPP-A and the IGF system.

Firstly discovered as a placental protein present abundantly in the circulation of pregnant women, pregnancy-associated plasma protein-A (PAPP-A) is widely expressed in multiple tissues. PAPP-A is a metalloproteinase that is able to specifically cleave three insulin-like growth factor binding proteins (IGFBPs): IGFBP-2, -4 and -5. PAPP-A binds tightly to glycosaminoglycans present on the surface of cells, thus functioning within tissues as a growth-promoting enzyme, releasing bioactive IGF in close proximity to the IGF receptor. Pro-MBP and stanniocalcin-2 (STC2) appear to be the main inhibitors of PAPP-A activity, by forming a covalent complex with the protease. According to in vivo experiments, IGFBP-4 is believed to be the main PAPP-A substrate to regulate IGF bioavailability. The regulation of PAPP-A includes transcriptional control of its gene, competing reactions with other IGFBPs potentially sequestering IGF from IGFBP-4 and hence antagonizing PAPP-A-mediated IGF activation, and proteolytic inhibition of PAPP-A. Finally, PAPP-A may serve as a therapeutic target to indirectly inhibit IGF signalling in tissues where this is driven by increased PAPP-A activity. By taking advantage of the intricate interaction between PAPP-A and IGFBP-4, highly specific and selective inhibition of PAPP-A is possible.

Cord blood level of insulin-like growth factor-1 and IGF binding protein-3 in monochorionic twins.

BACKGROUND/PURPOSE: Insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) are known to modulate fetal growth but their role in intrauterine growth of monochorionic twins (MCT) has not been studied. METHODS: Cord venous blood was collected directly after birth. IGF-1 and IGFBP-3 in the cord venous blood were quantified by radioimmunoassay. Birth weights (BWs) were obtained electronically. Placentas were examined for chorionicity. RESULTS: Cord blood was collected in 37 pairs of MCT (15 pairs were males). BWs ranged from 564 to 3240 g, and gestational ages (GAs) were between 24 weeks and 39 weeks. There was a correlation between BW and cord venous blood IGFBP-3 concentration (r = 0.28, p = 0.015), but not between BW and cord venous blood IGF-1 level. There was no difference in IGF-1 between the heavier twins (30.8 ± 61.8 ng/mL) and lighter twins (33.2 ± 63.7 ng/mL), but a trend (p = 0.096) of higher IGFBP-3 level was demonstrated in heavier twins (3.14 ± 1.23 µg/mL) than in lighter twins (2.71 ± 1.19 µg/mL). The IGFBP-3 levels were higher (p = 0.042) in female twins (3.20 ± 1.33 µg/mL) than in male twins (2.64 ± 1.04 µg/mL). The IGF-1 level of the heavier twins correlated significantly to their lighter co-twin (r = 0.73, p < 0.001). CONCLUSION: Our data showed that cord venous blood IGF-1 level might be controlled mainly by genetic factors. IGFBP-3 might play an important role in fetal growth.

Discovery of a novel insulin-like peptide and insulin binding proteins in the Eastern rock lobster Sagmariasus verreauxi.

This study reports, for the first time in any of the commercially important decapod species, the identification of an insulin-like peptide (ILP), distinct from the androgenic gland hormone. Bioinformatics analysis of the de novo assembled spiny lobster, (Sagmariasus verreauxi) transcriptome, allowed identification of Sv-ILP1 as well as eight binding proteins. Binding proteins were termed as Sv-IGFBP, due to homology with the vertebrate insulin-like growth-factor binding protein and Sv-SIBD1-7, single insulin-binding domain protein (SIBD), similar to those identified in other invertebrate species. Sv-ILP1 was found to be expressed in the eyestalk, gonads and antennal gland of both sexes and to a lesser extent in male muscle, androgenic gland and hepatopancreas. The expression profiles of each binding protein were found to vary across tissues, with Sv-SIBD5, 6 and 7 showing higher expression in the gonad, demonstrated by PCR and digital gene expression. Further spatial investigations, using in-situ hybridisation, found Sv-ILP1 to be expressed in the neurosecretory cells of the thoracic ganglia, in keeping with the tissue expression of Drosophila ILP7 (DILP7). This correlative tissue expression, considered with the phylogenetic clustering of Sv-ILP1 and DILP7, suggests Sv-ILP1 to be a DILP7 orthologue. The broad expression of Sv-ILP1 strongly suggests that ILPs have a role beyond that of masculinisation in decapods. The function of these novel peptides may have application in enhancing aquaculture practices in the commercially important decapod species.

Derivation and validation of cutoffs for clinical use of cell cycle arrest biomarkers.

BACKGROUND: Acute kidney injury (AKI) remains a deadly condition. Tissue inhibitor of metalloproteinases (TIMP)-2 and insulin-like growth factor binding protein (IGFBP)7 are two recently discovered urinary biomarkers for AKI. We now report on the development, and diagnostic accuracy of two clinical cutoffs for a test using these markers. METHODS: We derived cutoffs based on sensitivity and specificity for prediction of Kidney Disease: Improving Global Outcomes Stages 2-3 AKI within 12 h using data from a previously published multicenter cohort (Sapphire). Next, we verified these cutoffs in a new study (Opal) enrolling 154 critically ill adults from six sites in the USA. RESULTS: One hundred subjects (14%) in Sapphire and 27 (18%) in Opal met the primary end point. The results of the Opal study replicated those of Sapphire. Relative risk (95% CI) in both studies for subjects testing at ≤0.3 versus >0.3-2 were 4.7 (1.5-16) and 4.4 (2.5-8.7), or 12 (4.2-40) and 18 (10-37) for ≤0.3 versus >2. For the 0.3 cutoff, sensitivity was 89% in both studies, and specificity 50 and 53%. For 2.0, sensitivity was 42 and 44%, and specificity 95 and 90%. CONCLUSIONS: Urinary [TIMP-2]•[IGFBP7] values of 0.3 or greater identify patients at high risk and those >2 at highest risk for AKI and provide new information to support clinical decision-making. CLINICAL TRIALS REGISTRATION: Clintrials.gov # NCT01209169 (Sapphire) and NCT01846884 (Opal).

Characterization of GHRs, IGFs and MSTNs, and analysis of their expression relationships in blunt snout bream, Megalobrama amblycephala.

In order to test the hypothesis that the expression levels of GH/IGF axis genes would be negatively related to the expression of the myostatin genes in fish species, we cloned six growth regulating genes including growth hormone receptors-1/-2 (GHRs), insulin-like growth factors-I/-II (IGFs) and myostatins-a/-b (MSTNs) from blunt snout bream (Megalobrama amblycephala). The contents of mRNA transcripts for the six genes were determined in the different tissues of adult and developmental stages for the embryonic and larval periods. The results of quantitative real-time PCR showed that GHRs, IGFs and MSTNs were widely expressed in the tissues we tested, with the relatively lower expression levels in mesonephros, gonad and spleen for the six genes. The analysis of expression correlation coefficients among these six genes showed that GHR 1, GHR 2 and MSTN b were correlated with each other in adult tissues (P<0.01). For the developmental stages, GHR 1 had a similar expression pattern to GHR 2 during the examined periods, both with the highest expression levels at 160 hpf (hours post-fertilization) (P<0.05). IGF-II had higher expression levels than that of IGF-I before 400 hpf (P<0.05), while IGF-I was active after 52 hpf. The maximum of MSTN a and MSTN b mRNA levels were at 24 hpf and 400 hpf, respectively. The analysis of expression correlation coefficients showed that GHR 1, GHR 2, IGF-I, IGF-II and MSTN b were positively correlated with each other during embryonic development (P<0.01). The results from this study suggested that the relationship between GH/IGF axis genes and MSTNs was complex and not absolutely negative correlated in fish species.

The effect of Insulin like growth factor-I (IGF-I) and IGF binding protein-3 (IGFBP-3) on cellular proliferation in mouse 3T3 fibroblast cells / 결핵

BACKGROUND: Cell growth is a balance between cell proliferation and cell death. Insulin-like growth factor-I(IGF-I), which binds IGF-I receptor (IGF-IR), mediates cellular proliferation as a potent mitogen. IGF binding protein-3 (IGFBP-3) as a circulating major IGFBP can inhibit or enhance the effects of IGF-I on cellular growth by binding IGFs. METHODS: We investigated the expressions of mRNA of IGF-I and IGF-IR by northern blot and phosphorylation of IGF-IR with the treatment of IGF-I by western blot in 3T3 fibroblast cells. The cellular proliferations of 3T3 cells with the treatments of IGF-I were evaluated using 3H-thymidine incorporation and MTT assay. Also to observe the effect of IGFBP-3 on cellular proliferation, 3T3 cells were treated with anti-IGFBP-3 and alpha IR3(monoclonal antibody to IGF-IR) alone or in combination. RESULTS: Our results demonstrated that 3T3 cells showed mRNA expressions of IGF-I and IGF-IR and the IGF-I increased phosphorylation of IGF-IR. The treatments of 3T3 cells with IGF-I increased cellular proliferation in 5% and 1% seruma-containing media, not in serum-free media. The addition of anti-IGFBP-3 to neutralize IGFBP-3 showed 2-fold increase of cellular proliferation, and also co-incubation of anti-IGFBP-3 and alpha IR3 together showed similar increase of cellular proliferation in 3T3 cells. Interestingly, when the cells were prethreated with alpha IR3 for 4 hr, prior to the simultaneous addition of alpha IR3 and anti-IGFBP-3, anti-IGFBP-3-mediated cellular proliferation was decreased to control level. All of these results suggest that free IGF-I released from IGF-I/IGFBP-3 complex would be involved in the cellular proliferation. CONCLUSION: IGF-I action by binding IGF-I.