IGF-binding Protein-3 Levels Research Articles

Influence of neonatal anthropometry on the comorbidities of the patient with obesity

IntroductionSmall for gestational age (SGA) newborns show an increased risk of several diseases such as short stature, childhood obesity, Eliminar la comand metabolic comorbidities. Patients and methodsThe study included 883 patients with obesity (47% females/53% males; mean age: 10.33±3.32 years, BMI: +3.93±1.42 SDS), with prospective follow-up (5 years) of growth, recording adult height when achieved (n=104). Comparisons at diagnosis, according to their neonatal anthropometry; adequate for gestational age (AGA; n=810) vs. SGA (n=73), were performed for the following features: age at their first visit, standardised height for target height (z-score), bone age, adult height prediction, BMI (z-score), glycaemia, insulinaemia, HOMA, total cholesterol, HDL, LDL, triglycerides, 25-OH-vitamin D, area under the curve (AUC) for glucose and insulin in the OGTT, LDL/HDL and triglyceride/HDL ratio, insulin-like growth factor (IGF-I) and IGF-binding protein 3 (IGFBP-3) serum levels. ResultsDespite similar BMI-SDS, ethnic, and pubertal distribution in both groups, patients with SGA showed more severe changes in lipid profile (triglyceride and triglyceride/HDL ratio, both P<.05) and carbohydrate metabolism (higher glycaemia, glucose and insulin AUCs, HOMA, HbA1c and lower whole-body insulin sensitivity index (WBISI), all P<.05) and lower 25-OH vitamin D levels (P<.05). They also showed a poorer adult height prediction (adjusted for target height) (P<.01), despite a similar degree of advance in skeletal maturation and similar IGF-I and IGFBP-3 levels than AGA patients. ConclusionsThe background of SGA neonatal anthropometry is associated with a higher prevalence and severity of metabolic comorbidities and to a poorer adult height prediction in obese children and adolescents.

SUN-267 Relationship between Height Velocity and Change of Serum Insulin-Like Growth Factor-1 and Insulin-Like Growth Factor Binding Protein-3 Concentrations during Gonadotropin-Releasing Hormone Agonist Treatment in Korean Girls with Idiopathic Central Precocious Puberty

Purpose : This study aims to investigate the effect of gonadotropin-releasing hormone agonist (GnRHa) on the growth velocity during treatment in Korean girls with idiopathic central precocious puberty (ICPP). Methods : Data was collected from 97 girls, diagnosed under 9 year of age and treated by GnRHa for at least 1 year between 2014 and 2015. Their body height, weight, ∆ Height standard deviation score (SDS), serum insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) concentrations and bone age were measured at the start and after a year of GnRHa treatment. Possible correlations between the variables were calculated. Results : During the treatment, height SDS, IGF-1 SDS, IGFBP-3 SDS and IGF-1/IGFBP-3 ratio significantly decreased. There were significant correlations between serum IGF-1 level and ∆ Height SDS (r=0.405, p=0.000), and between serum IGFBP-3 level and ∆ Height SDS (r=0.228, p=0.025). C allele had significant correlation with IGFBP-3 level (p=0.004) but had no significant correlation with ∆ Height SDS (p=0.947). Conclusions : The results suggest that the height velocity during GnRHa treatment may be related to serum IGF-1 and IGFBP-3 concentration thus GnRHa may affect GH-IGF-1 axis.

SUN-439 Improvement in Insulin-Like Growth Factor-1 and Clinical Symptoms: Results of an Open-Label, Single-Arm Study of a Human Growth Hormone-Enhancing Amino Acid Supplement

SeroVital is an orally-administered amino acid supplement that promotes hGH secretion via suppression of somatostatin. We investigated if daily administration of the supplement would increase levels of endogenous insulin-like growth factor 1 (IGF-1), a primary mediator of the effects of hGH, and improve symptoms related to low-normal hGH production in a cohort of individuals being treated for fibromyalgia, a complicated condition associated with endocrine features including low or low-normal hGH. This open-label, single-arm study investigated the effects of 24 weeks of daily oral administration of the supplement in individuals with low-normal hGH production (between the 15th and 50th percentile for age-appropriate levels of IGF-1). The primary endpoint was the change from baseline to endpoint (Week 24) in serum IGF-1. Additional endpoints included the change in body weight, clinical symptoms (assessed with the Revised Fibromyalgia Impact Questionnaire [FIQR], range 0-100, and Perceived Stress Scale [PSS], range 0-40), fasting cardiometabolic markers, tolerability, and safety. Participants continued to receive standard care. The study enrolled 45 adults with mean baseline age (mean±SD) 67±11 years, 67% female, BMI 31±7 kg/m2, and IGF-1 107±28 ng/mL. High mean±SD baseline FIQR and PSS scores of 82±14 and 35±3, respectively, indicated poor to moderate control of fibromyalgia with standard care. All individuals completed 24 weeks of treatment. There was an increase in serum IGF-1 levels at Week 12 that was sustained to endpoint, resulting in a mean±SE Week 24 change of 32.1±2.8 ng/mL (paired t-test p<0.001). IGF binding protein-3 (IGFBP-3) levels were unchanged from baseline (p=ns), indicating no change in IGF-1 sensitivity. There was a steady reduction in body weight that resulted in Week 24 mean±SE change of -6.4±0.4 kg (p<0.001). The change from baseline in FIQR and PSS scores were -25.6±1.6 and -21.5±0.5, respectively (both p<0.001), indicating a substantial improvement. Statistically significant improvements from baseline were also observed for systolic and diastolic blood pressure, HbA1c, LDL and HDL cholesterol, and triglycerides (all p<0.001). The supplement was well tolerated; no adverse events were reported. In patients being treated for fibromyalgia with low-normal hGH production, daily addition of the hGH-enhancing supplement for 24 weeks produced an increase in IGF-1 with associated weight loss and improvements in cardiometabolic markers and clinical symptoms. Sustained augmentation of IGF-1 with the supplement may represent a unique method of improving clinical symptoms in individuals with low-normal hGH, including otherwise healthy adults exhibiting low-normal hGH production.This was an independent investigator-initiated study. Sierra Research Group provided some samples of the supplement.

SUN-049 Growth Hormone Deficiency Associated with a Rare Overgrowth Syndrome

Background: The Megalencephaly Capillary Malformation syndrome (MCAP) is a genetic overgrowth disorder characterized by brain overgrowth, polymicrogyria, vascular malformations, and segmental somatic overgrowth secondary to activating mutations in the PI3K-AKT-mTOR pathway (PIK3CA). Congenital macrosomia and postnatal asymmetric overgrowth is typical in this condition, however both growth failure and hypoglycemia have been reported in a significant fraction of affected children raising the concern for growth hormone deficiency (GHD). Methods: We performed an observational multi-institution study of children with MCAP and GHD. Medical records were abstracted including growth trajectories, laboratory data, and treatment response to growth hormone (GH), if applicable. Results: Eight participants (4 female, 4 male) were diagnosed with GHD at mean age of 3.2 years. All had very low or undetectable insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGF-BP3) concentrations. Four underwent GH stimulation testing and all had insufficient responses with a median peak GH of 3.1 ng/ml (range 1.1-7.3). Growth patterns revealed a drastic decline in height z-scores within the first year of life from greater than 2.0 at birth to less than -2.0 z-score by 12 months of age. Growth velocity was in the low-normal range between 1-4 years of age therefore height z-scores were stable but remained low. Four of the 8 had hypoglycemia with fasting. Central hypothyroidism was diagnosed in one and adrenal insufficiency in another. Brain MRI reports were available in 7 children and all had a structurally normal pituitary gland. Three children were treated with GH; one became inconsolable after one week of treatment and it was discontinued. The other two children have continued on GH with excellent responses in linear growth velocity. Conclusion: Profound GHD is a notable feature of MCAP, a condition with gain-of-function mutations promoting cell growth and proliferation. Therefore, children with MCAP and either hypoglycemia and/or postnatal growth failure should be evaluated for GHD. The universally low IGF-BP3 levels in this cohort were striking given this is an unusual finding even in GHD. Additional research is needed into the mechanisms underlying this phenomenon as well as whether treatment with GH is effective and safe in this condition.

Association between Insulin-Like Growth Factor-I Levels and the Disease Progression and Anemia in Visceral Leishmaniasis.

We analyzed the association between insulin-like growth factor-I (IGF-I) and the pathogenesis of anemia during active visceral leishmaniasis (VL). Serum levels of IGF-I, IGF-binding protein 3 (IGFBP3), and cytokines were measured in samples from individuals with active VL and cured VL, asymptomatic Leishmania-infected, and noninfected individuals. Then, we extended our analysis to VL dogs to evaluate hematimetric parameters, bone marrow alterations, and cytokine and IGF-I expression. We identified a positive correlation between lower IGF-I and IGFBP3 levels in active VL patients and lower hemoglobin levels. In infected dogs, there was a positive correlation between lower IGF-I expression in the bone marrow and lower peripheral blood hematocrit and hemoglobin levels. There was no correlation between decreased IGF-I level/expression and any measured cytokine serum levels in either host. The data suggest that low IGF-I expression is associated with pathogenesis of anemia in active VL, primarily in severe cases, by mechanisms other than alterations in cytokine production.

Serum IGF-binding protein 2 (IGFBP-2) concentrations change early after gastric bypass bariatric surgery revealing a possible marker of leptin sensitivity in obese subjects.

Expression of IGFBP-2 in mice is regulated by leptin. Over-expression of IGFBP-2 is associated with reduced caloric intake and resistance to weight gain. Hormonal variations contributing to weight loss occur very early after bariatric surgery but have not been fully elucidated. We evaluated IGFBP-2 serum changes after bariatric surgery and their relationship with leptin variations to test the hypothesis that an increase of leptin sensitivity may explain some of the effects of gastric bypass. This is a historical prospective study. Fifty-one obese patients (41 women e 10 men), 9 non-obese surgical controls and 41 lean matched controls were studied. Serum IGFBP-2 and leptin were measured after bariatric bypass surgery at various time points up to 18 months, after non-bariatric laparoscopic surgery in a control group, and in lean matched controls. Compared to lean controls, serum IGFBP-2 levels were lower in obese patients. After gastric bypass, IGFBP-2 significantly increased at 3 days and became normal before the occurrence of relevant changes in body weight, remaining stable up to 18 months after surgery. IGFBP-2/leptin ratio increased early after surgery and became normal after one year. After gastric bypass, serum IGFBP-2 increases in a window of time when variations of hormones mediating the effects of bariatric surgery occur. Our results suggest that IGFBP-2, a leptin-regulated protein, may be an in-vivo marker of leptin action. If this is the case, an early improvement of leptin sensitivity might contribute to the anorectic effect of gastric bypass.

Relation of IGF-1 and IGFBP-3 with prevalent and incident atrial fibrillation in a population-based study

Insulin-like growth factor 1 (IGF-1) and its main binding protein insulin-like growth factor binding protein 3 (IGFBP-3) have been related to several cardiovascular diseases. The relation with atrial fibrillation (AF) is largely unknown. The objective of this study was to investigate the association of IGF-1 and IGFBP-3 levels with prevalent and incident AF in a large population-based study. Data from the Study of Health in Pomerania (SHIP) were collected. At presentation, a medical examination, standardized electrocardiographic assessment, and measurements of serum IGF-1 and IGFBP-3 levels were performed. Incident AF was assessed in individuals without AF at baseline (SHIP-1) who developed AF during follow-up (SHIP-2; after a mean of 5.2 years). Of 3160 participants, 66 (2.1%) exhibited AF at baseline. IGF-1 levels and IGF-1/IGFBP-3 ratios were significantly lower in individuals with AF than in those without AF (IGF-1: 104.2 ± 41.6 ng/mL vs 142.9 ± 53.5 ng/mL, P < .001 and IGF-1/IGFBP-3: 0.031 ± (0.009 ng/mL vs 0.036 ± 0.010 ng/mL, P = .006, respectively). Multivariable-adjusted logistic regression models showed that a low IGF-1/IGFBP-3 ratio was associated with prevalent AF (odds ratios 0.67; 95% confidence interval 0.48-0.94; P = .021). Of 1817 individuals without AF at baseline, 27 (1.5%) developed AF during follow-up. In these participants, IGF-1 levels, but not IGF-1/IGFBP-3 ratios, were significantly lower (IGF-1: 113.3 ± 38.6 ng/mL vs 147.2 ± 51.6 ng/mL, P = .013 and IGF-1/IGFBP-3: 0.033 ± 0.008 ng/mL vs 0.036 ± 0.010 ng/mL, P = .176). Low IGF-1/IGFBP-3 ratios are associated with a higher prevalence of AF. There seems to be a similar impact in incident AF.

Analyses of IGFBP2 DNA methylation and mRNA expression in visceral and subcutaneous adipose tissues of obese subjects

Insulin-like growth factor binding-protein 2 (IGFBP-2) is secreted by differentiating white adipocytes. Clinical studies demonstrate that circulating IGFBP-2 levels associated inversely with body mass index (BMI) and insulin resistance. To explore possible epigenetic changes of the IGFBP2 gene in obesity, we analyzed DNA methylation and mRNA expression in adipocytes from different depots. Healthy lean controls (BMI = 24.5 ± 0.3 kg/m2, n = 19) and obese subjects (BMI > 35 kg/m2, n = 24) were recruited. All subjects were Swedish Caucasian. Visceral abdominal adipose tissue (VAT) and subcutaneous adipose tissue (SAT) fragments were homogenized. Genomic DNA and total RNAs were extracted. Four CpG sites in the IGFBP2 gene promoter region were analyzed with bisulfite pyrosequencing. IGFBP2 gene expression at mRNA levels was determined with TaqMan real time RT-PCR. Serum samples were used for measurement of circulating IGFBP-2 and leptin levels. IGFBP2 DNA methylation levels in VAT were increased in obese subjects compared with controls (P < .05). By contrast, IGFBP2 mRNA expression levels in VAT were lower in obesity subjects than in controls (P < .05). In SAT, IGFBP2 DNA methylation and RNA expression levels were lower than in VAT, irrespective of obesity. Obese subjects demonstrated increased serum leptin levels (P < .001) and reduced serum IGFBP-2 levels compared to controls (P < .05). In conclusion, the current study demonstrates that IGFBP2 DNA methylation levels are increased in VAT from obese subjects. This suggests that IGFBP-2 is epigenetically regulated in abdominal obesity.

The Effect of Serum Igf-1,Igfbp-3 And Erythrocyte Transfusıons on Development of Mıld Retınopathy of Prematurıty

Introduction: Most important factors in retinopathy of prematurity (ROP) are prematurity and oxygen toxicity although blood transfusions, insulin like growth factor-1 ( IGF-1), insulin like growth factor binding protein 3 (IGFBP-3) and vascular endothelial growth factor (VEGF) also have important roles. The objectives of this study were, to measure IGF-1 and IGFBP-3 levels in preterm newborns before and after blood transfusion and assess if the effect of transfusion in development of ROP is via these mediators, and to investigate whether IGF-1 and IGFBP-3 levels measured at 32 and 33 gestational age (GA) were different in preterm newborns with and without ROP. Material and Methods: Preterm newborns with gestational age ≤34 weeks were included and blood samples were obtained before and after red blood cell (RBC) transfusion. Results: Thirty newborns were included, 17 of whom had ROP ( stage 1: n=11, stage 2: n=5, stage 3: n=1). IGF-1 and IGFBP-3 levels did not change after RBC tranfusion. Excluding the patient with stage 3 ROP all ROP patients were referred as mild ROP. No difference was observed between IGF-1 and IGFBP-3 levels of the patients with and without mild ROP. Patients with mild ROP had significantly more number of transfusions. Conclusions: Erythrocyte transfusion increased the frequency of ROP, whereas IGFBP-3 and IGF-1 were not associated of ROP.

Analysis of the value and correlation of IGF-1 with GH and IGFBP-3 in the diagnosis of dwarfism.

Correlation between the value of insulin-like growth factor-1 (IGF-1) in the diagnosis of dwarfism and the levels of growth hormone (GH) and insulin-like growth factor binding protein-3 (IGFBP-3) was investigated. From April 2014 to June 2017, 122 children with dwarfism who were treated in The Affiliated Wuxi No. 2 People's Hospital of Nanjing Medical University and The First Affiliated Hospital of Xinxiang Medical University were selected as the experimental group, and 51 normal children as the control group. The basic information was recorded in detail; serum GH and IGFBP-3 levels were measured using an arginine stimulation test and an insulin hypoglycemia stimulation test, respectively. According to the peak of GH in the experimental group, there were 65 cases of growth hormone deficiency (GHD) and 57 cases of idiopathic short stature (ISS). The expression levels of IGF-1 of the serum in the experimental and control group were detected by chemiluminescence immunoassay (CLIA). The correlation between IGF-1 and GH, IGF-1 and IGFBP-3 was analyzed. The expression level of serum IGF-1 in GHD group was significantly lower than that in the ISS group (P<0.05). The expression level of serum IGF-1 in GHD group was significantly lower than that in the control group (P<0.05). The expression level of serum IGF-1 in ISS group was significantly lower than that in the control group (P<0.05). The results of partial correlation studies showed that IGF-1 is positively correlated with GH and IGFBP-3. Detection of GH and IGFBP-3 are important for the early diagnosis and comprehensive evaluation of children with dwarfism, and also in the detection of IGF-1 can reflect the therapeutic effect of dwarfism on recombinant human growth hormone (rhGH) treatment, which is worthy of application in clinics.

Contribution of Liver Fat to Weight Loss-Induced Changes in Serum Hepatokines: A Randomized Controlled Trial.

Hepatokines have emerged as potential mediators of obesity-associated comorbidities, such as type 2 diabetes, cardiovascular disease, fractures, and central hypogonadism. To assess whether weight loss-induced changes in hepatokines are mediated by intrahepatic triglyceride (IHTG) content. Cross-sectional study and randomized controlled trial. General community. Metabolically healthy, lean men (waist <94 cm; n = 25) and men with abdominal obesity (waist 102 to 110 cm; n = 52). Men with abdominal obesity were randomized to 8-week dietary weight loss or no weight loss. IHTG and serum hepatokines, that is, serum IGF1, IGF binding protein 1 (IGFBP1), SHBG, fibroblast growth factor 21 (FGF21), fetuin A, and plasma fetuin B. All hepatokines, except for fetuin B, were significantly different between lean men and men with obesity. After the weight-loss intervention (-10.3 kg; 95% CI, -11.4 to-9.2), serum IGF1, IGFBP1, SHBG, and fetuin A approached the values observed in lean men. Cross-sectional associations were observed between IHTG and IGF1 (β = -0.51; 95% CI, -0.82 to -0.20), IGFBP1 (β = -4.2; 95% CI, -7.7 to -0.7), and FGF21 (β = 2.1; 95% CI, 1.3 to 2.9) in lean men and men with abdominal obesity combined. Weight loss resulted in a reduction of IHTG (treatment effect, -2.2%; 95% CI, -3.4% to -1.2%) that was associated with a change in IGF1 (β = -0.9; 95% CI, -1.3 to -0.4), IGFBP1 (β = -0.17; 95% CI, -0.31 to -0.03), and SHBG levels (β = -0.18; 95% CI, -0.29 to -0.07). Mediation analyses showed that only the weight loss-induced change in serum IGF1 was mediated by IHTG (mediated effect, 32.7%; 95% CI, 4.6% to 79.2%). Dietary weight loss has differential effects on hepatokines. This study shows that the change in serum IGF1 levels after dietary weight loss is mediated by the change in IHTG content.

Distribution of insulin growth factor-1 (IGF-1) binding proteins in hepatocellular carcinoma with and without cirrhosis.

193 Background: Circulating insulin-like growth factor-1 (IGF-1) significantly declines in patients (pts) with cirrhosis and hepatocellular carcinoma (HCC), reflecting damaged hepatocytes. The bioavailability of IGF-1 is controlled by insulin-like growth factor binding proteins (IGFBPs), which bind IGF-1. IGFBPs transcription is cell specific, and are secreted mainly by the liver. Variations in circulating IGFBPs in HCC pts, especially those with non-cirrhotic HCC, has not been elucidated. We investigated the expression of these proteins in HCC with and without cirrhosis. Methods: Under Institutional Review Board approval, we measured plasma levels of seven IGFBPs in 489 cirrhotic HCC pts, 274 non-cirrhotic HCC pts, 75 pts with cirrhosis without HCC, and 200 healthy controls. Also, we assessed variations in IGFBPs plasma level between early and advanced stage HCC in the presence and absence of cirrhosis. Levels of circulating biomarkers were summarized by descriptive statistics, and both Chi-square and ANOVA tests were used to compare levels between groups. Results: IGFBPs levels varied significantly between groups (Table). Moreover, IGFBP-3 was lower in HCC pts than in healthy controls ( P ≤ 0.001), and IGFBP-1, -2, -4, and -7 were higher in HCC without cirrhosis than in healthy controls ( P = 0.001 for all). Additionally, in non-cirrhotic HCC pts, a similar pattern was observed in advanced Stage HCC compared with early stage HCC. Conclusions: Levels of circulating IGFBPs may be associated with risk of non-cirrhotic HCC and could be used as markers for underlying liver damage. [Table: see text]

Immune biomarkers in maternal plasma to identify histologic chorioamnionitis in women with preterm labor.

To determine whether various selected immune-related proteins in maternal plasma, alone or in combination, can predict histologic chorioamnionitis (HCA) in women with preterm labor, and to compare the predictive abilities of these biomarkers with that of serum C-reactive protein (CRP). This retrospective cohort study included 74 consecutive women with preterm labor (23-34 gestational weeks) who delivered within 96h of blood sampling. Their serum CRP levels were also measured. The stored maternal plasma was assayed for interleukin (IL)-6, matrix metalloproteinase (MMP)-9, tissue inhibitor of metalloproteinases (TIMP)-1, angiopoietin-2, S100 A8/A9, CXCL14, APRIL, and insulin-like growth factor-binding protein-2 (IGFBP-2), using ELISA kits. The primary outcome measure was HCA. HCA was detected in 59.4% (44/74) of women. Women with HCA had a significantly lower median gestational age at sampling and plasma IGFBP-2 level, and higher median plasma IL-6 and S100 A8/A9 levels than those without HCA. In multivariable analysis, high plasma IL-6 and low plasma IGFBP-2 levels were independently associated with the occurrence of HCA. However, the sensitivities, specificities, and areas under the curve of plasma IL-6, S100 A8/A9, and IGFBP-2, alone or in combination, were similar to or lower than those of serum CRP, for detecting HCA. Our data suggest that plasma IL-6, S100 A8/A9, and IGFBP-2 could be potential novel biomarkers for predicting HCA in women with PTL; however, elevated plasma levels of these biomarkers, alone or in combination, do not predict HCA better than serum CRP.

骨粗鬆症重症度を判断するマーカーとしての血中insulin‐like growth factor‐I(IGF‐I)とIGF結合タンパク‐3値の有用性

骨粗鬆症重症度を判断するマーカーとしての血中insulin‐like growth factor‐I(IGF‐I)とIGF結合タンパク‐3値の有用性

Insulin-like growth factor binding protein-4 exerts antifibrotic activity by reducing levels of connective tissue growth factor and the C-X-C chemokine receptor 4.

The insulin‐like growth factor (IGF) system plays an important role in variety cellular biological functions; we previously reported levels of IGF binding proteins (IGFBP)‐3 and ‐5 are increased in dermal and pulmonary fibrosis associated with the prototypic fibrosing disease systemic sclerosis (SSc), induce extracellular matrix (ECM) production, and promote fibrosis. We sought to examine the effects of another member of the family, IGFBP‐4, on ECM production and fibrosis using cell‐based, ex vivo organ culture and in vivo mouse lung fibrosis models. IGFBP‐4 mRNA levels were significantly decreased in pulmonary fibroblasts of patients with SSc. ECM components were significantly reduced by endogenous and exogenous IGFBP‐4. IGFBP‐4 also blocked TGF‐β–induced ECM production, and inhibited ECM production ex vivo in human lung and skin in organ culture. In vivo, IGFBP‐4 reduced bleomycin‐induced collagen production and histologic evidence of fibrosis. Silencing IGFBP‐4 expression to mimic levels observed in SSc lung fibroblasts resulted in increased ECM production. IGFBP‐4 reduced mRNA and protein levels of the chemokine receptor CXCR4 and the profibrotic factor CTGF. Furthermore, CTGF silencing potentiated the antifibrotic effects of IGFBP‐4. Reduced IGFBP‐4 levels in SSc lung fibroblasts may contribute to the fibrotic phenotype via loss of IGFBP‐4 antifibrotic activity.

Activation of EGFR-DNA-PKcs pathway by IGFBP2 protects esophageal adenocarcinoma cells from acidic bile salts-induced DNA damage

BackgroundThe incidence of esophageal adenocarcinoma (EAC) is rising rapidly in the US and Western countries. The development of Barrett’s esophagus (BE) and its progression to EAC have been linked to chronic gastroesophageal reflux disease (GERD). Exposure of BE and EAC cells to acidic bile salts (ABS) in GERD conditions induces high levels of oxidative stress and DNA damage. In this study, we investigated the role of insulin-like growth factor binding protein 2 (IGFBP2) in regulating ABS-induced DNA double-strand breaks.MethodsReal-time RT-PCR, western blot, immunohistochemistry, immunofluorescence, co-immunoprecipitation, flow cytometry, and cycloheximide (CHX) chase assays were used in this study. To mimic GERD conditions, a cocktail of acidic bile salts (pH 4) was used in 2D and 3D organotypic culture models. Overexpression and knockdown of IGFBP2 in EAC cells were established to examine the functional and mechanistic roles of IGFBP2 in ABS-induced DNA damage.ResultsOur results demonstrated high levels of IGFBP2 mRNA and protein in EAC cell lines as compared to precancerous Barrett’s cell lines, and IGFBP2 is frequently overexpressed in EACs (31/57). Treatment of EAC cells with ABS, to mimic GERD conditions, induced high levels of IGFBP2 expression. Knocking down endogenous IGFBP2 in FLO1 cells (with constitutive high levels of IGFBP2) led to a significant increase in DNA double-strand breaks and apoptosis, following transient exposure to ABS. On the other hand, overexpression of exogenous IGFBP2 in OE33 cells (with low endogenous levels of IGFBP2) had a protective effect against ABS-induced double-strand breaks and apoptosis. We found that IGFBP2 is required for ABS-induced nuclear accumulation and phosphorylation of EGFR and DNA-PKcs, which are necessary for DNA damage repair activity. Using co-immunoprecipitation assay, we detected co-localization of IGFBP2 with EGFR and DNA-PKcs, following acidic bile salts treatment. We further demonstrated, using cycloheximide chase assay, that IGFBP2 promotes EGFR protein stability in response to ABS exposure.ConclusionsIGFBP2 protects EAC cells against ABS-induced DNA damage and apoptosis through stabilization and activation of EGFR - DNA-PKcs signaling axis.

Proteome Analyses Reveal Positive Association of COL2A1, MPO, TYMS, and IGFBP5 with Canine Mammary Gland Malignancy.

To identify aberrantly expressed proteins contributing to pathogenesis of canine mammary tumors (CMTs) which are the most prevalent neoplasms in female dogs and include different types. Frozen tissue specimens of normal mammary gland (n = 7), lobular hyperplasia (n = 6), simple carcinoma (n = 6), and complex carcinoma (n = 6) are collected from 11 CMT cases. Tissue homogenates are comparatively analyzed by the isobaric tags for relative and absolute quantification (iTRAQ) combined with LC-MS/MS to identify proteins differentially expressed in different-type CMT tissues. Among 3795 proteins identified and quantified among all groups, 133, 127, and 98 proteins are particularly overexpressed in simple carcinoma, complex carcinoma, and both types, respectively, compared with normal and hyperplastic tissues. Moreover, collagen type II alpha 1 chain (COL2A), myeloperoxidase (MPO), thymidylate synthetase (TYMS), and insulin-like growth factor-binding protein 5 (IGFBP5) are validated to be highly expressed in different-type CMT tissues using immunoblotting and immunohistochemistry. Notably, COL2A1 and IGFBP5 levels are correlated with clinical stages. COL2A1, MPO, TYMS, and IGFBP5 protein levels are positively associated with CMT development. Data expedite further investigations to improve treatment regimens for CMT.

Growth Hormone's Links to Cancer.

Several components of the GH axis are involved in tumor progression, and GH-induced intracellular signaling has been strongly associated with breast cancer susceptibility in genome-wide association studies. In the general population, high IGF-I levels and low IGF-binding protein-3 levels within the normal range are associated with the development of common malignancies, and components of the GH-IGF signaling system exhibit correlations with clinical, histopathological, and therapeutic parameters in cancer patients. Despite promising findings in preclinical studies, anticancer therapies targeting the GH-IGF signaling system have led to disappointing results in clinical trials. There is substantial evidence for some degree of protection against tumor development in several animal models and in patients with genetic defects associated with GH deficiency or resistance. In contrast, the link between GH excess and cancer risk in acromegaly patients is much less clear, and cancer screening in acromegaly has been a highly controversial issue. Recent studies have shown that increased life expectancy in acromegaly patients who attain normal GH and IGF-I levels is associated with more deaths due to age-related cancers. Replacement GH therapy in GH deficiency hypopituitary adults and short children has been shown to be safe when no other risk factors for malignancy are present. Nevertheless, the use of GH in cancer survivors and in short children with RASopathies, chromosomal breakage syndromes, or DNA-repair disorders should be carefully evaluated owing to an increased risk of recurrence, primary cancer, or second neoplasia in these individuals.

Insulin-like Growth Factor Binding Protein-3 (IGFBP3) Induces Fetal Hemoglobin in Hematopoietic Stem and Progenitor Cells from Patients with Sickle Cell Anemia

Background: Fetal hemoglobin (HbF, α2g2) induction is known to reduce the clinical complications of sickle cell anemia (SCA). Progress in identifying novel HbF inducing strategies has been slowed by an incomplete understanding of gamma-globin regulation. We have used natural genetic variation to identify novel genes and pathways associated with HbF levels in patients with SCA, beginning with whole exome sequencing (WES). This approach identified FOXO3, a transcription factor important for insulin signaling and erythroid maturation, among other functions, as a positive regulator of HbF. We then confirmed the role of FOXO3 in HbF regulation with functional studies in erythroid culture (Zhang, Blood 2018). To overcome the limitations of WES, namely the absence of regulatory and promotor sequencing data, we performed whole genome sequencing (WGS) on 658 pediatric SCA patients, and analyzed the data for common variants predictive of HbF levels.Methods: WGS was performed on a cohort of 658 pediatric patients with HbSS and HbSβ0 with IRB approval from Texas Children's Hospital, and from St Jude Children's Research Hospital, as part of the Sickle Cell Clinical Research and Intervention Program (Hankins et al 2018). Baseline HbF levels, not on hydroxyurea therapy, was measured by HPLC. Subjects were between 6 months and 21 years of age from both institutions; 52% were male. We used mixed linear regression models to screen for variants associated with transformed HbF values, and performed ridge regression with 10-fold cross-validation to confirm associations after adjustment for HBG and BCL11A-associated variants, age, sex, and race (determined by principal components analysis).Hematopoietic stem and progenitor cells (HSPCs) from 3 patients (all HbSS) were treated with recombinant human IGFBP3 (1µg/ml) beginning on day 7 of two-phase culture. Effects of IGFBP3 on gamma-globin expression were evaluated by RT-qPCR, and on HbF levels by HPLC, on days 14 and 21 of culture. The effects of IGFBP3 on known modifiers of HbF and the FOXO3 pathway were assessed by RT-qPCR and western blot on day 21 of culture. Erythroid maturation was assessed by flow cytometry using anti-CD71, GPA, and Band3 on day 21 of culture.Results: Our whole genome sequencing data identified a strong association between all 11 variants 200 kb upstream of IGFBP3 and baseline HbF levels (p<1x10-9). The association of IGFBP3 variants with HbF remained after correcting for HBG and BCL11A variants in addition to patient age, sex, and race (p<0.001). Eleven SNPs were tested, and corrected for multiple testing. Mean HbF levels for patients heterozygous for an IGFBP3 variant predicted to alter IGFBP3 levels as determined by NESDA conditional eQTL catalog (Jenson et al, 2017) were 43% higher compared to patients without a variant (t-test p<0.0002).In erythroblasts treated with IGFBP3, gamma globin expression doubled compared to untreated (p=0.01). %HbF in IGFBP3 treated cells at day 21 of culture was the same as on day 14, while the HbF of untreated cells declined (Figure 1). IGFBP3 did not alter expression of known gamma globin regulators BCL11A, KLF1, and MYB, nor did it alter erythroid maturation as measured by flow cytometry with anti-CD71, GPA, and Band3, and morphologic examination.Conclusions: WGS analysis identified variants in the regulatory region of IGFBP3 as associated with higher levels of HbF. Addition of exogenous human recombinant IGFBP3 to HSPCs prevented the physiologic decline of HbF, resulting in higher %HbF levels in erythroblasts, functionally confirming the association. Exogenous IGFBP3 did not arrest maturation, supporting our hypothesis that IGFBP3 affects HbF production directly via gamma globin induction, rather than through manipulation of maturation. IGFBP3 did not alter expression of known regulators of HbF (BCL11A, KLF1, and MYB). These findings are compatible with our prior data identifying FOXO3 as a positive regulator of gamma globin, and our use of metformin as a HbF inducer in an ongoing clinical trial. Metformin increases IGFBP3 levels, and it has been shown that increases in IGFBP3 lead to activation of FOXO3 through the insulin signaling pathway. We therefore conclude that the insulin signaling pathway plays a significant role in gamma-globin regulation and is an important therapeutic target for HbF induction in patients with SCA. DisclosuresHankins:Global Blood Therapeutics: Research Funding; bluebird bio: Consultancy; Novartis: Research Funding; NCQA: Consultancy. Estepp:Global Blood Therapeutics: Consultancy, Research Funding; NHLBI: Research Funding; Daiichi Sankyo: Consultancy; ASH Scholar: Research Funding.

Pappa2 deletion has sex- and age-specific effects on bone in mice

ObjectiveIn humans, loss-of-function mutations in the gene encoding pregnancy-associated pregnancy protein-A2 cause short stature and slightly reduced bone density. The goal of this study was to determine the effects of Pappa2 deletion on bone in mice. DesignPappa2 deletion mice and littermate controls were culled at 10, 19 or 30 weeks of age and femurs were analysed by micro-computed tomography. Serum markers of bone turnover and insulin-like growth factor binding protein 5 (IGFBP-5), a proteolytic target of PAPP-A2, were measured by ELISA. ResultsAt 10 and 19 weeks of age, Pappa2 deletion mice had slightly reduced trabecular parameters, but by 19 weeks of age, female deletion mice had increased cortical tissue mineral density, and this trait was increased by a small amount in deletion mice of both sexes at 30 weeks. Cortical area fraction was increased in Pappa2 deletion mice at all ages. Deletion of Pappa2 increased circulating IGFBP-5 levels and reduced markers of bone turnover (PINP and TRACP 5b). ConclusionsPAPP-A2 contributes to the regulation of bone structure and mass in mice, likely through control of IGFBP-5 levels. The net effect of changes in bone formation and resorption depend on sex and age, and differ between trabecular and cortical bone.