Comparison of acid ethanol extraction and acid gel filtration prior to IGF-I and IGF-II radioimmunoassays: improvement of determinations in acid ethanol extracts by the use of truncated IGF-I as radioligand

Adiponectin, IGFBP-1 and -2 are independent predictors in forecasting prediabetes and type 2 diabetes

Objective

Adiponectin and insulin-like growth factor (IGF) binding proteins IGFBP-1 and IGFBP-2 are biomarkers of insulin sensitivity. IGFBP-1 reflects insulin sensitivity in the liver, adiponectin in adipose tissue and IGFBP-2 in both tissues. Here, we study the power of the biomarkers adiponectin, IGFBP-1, IGFBP-2, and also included IGF-I and IGF-II, in predicting prediabetes and type 2 diabetes (T2D) in men and women with normal oral glucose tolerance (NGT).

Design

Subjects with NGT (35-56 years) recruited during 1992-1998 were re-investigated 8-10 years later. In a nested case control study, subjects progressing to prediabetes (133 women, 164 men) or to T2D (55 women, 98 men) were compared with age and sex matched NGT controls (200 women and 277 men).

Methods

The evaluation included questionnaires, health status, anthropometry, biochemistry and oral glucose tolerance test.

Results

After adjustment, the lowest quartile of adiponectin, IGFBP-1 and IGFBP-2 associated independently with future abnormal glucose tolerance (AGT) in both genders in multivariate analyses. High IGFs predicted weakly AGT in women. In women, low IGFBP-2 was the strongest predictor for prediabetes (OR:7.5), and low adiponectin for T2D (OR:29.4). In men, low IGFBP-1 was the strongest predictor for both prediabetes (OR:13.4) and T2D (OR:14.9). When adiponectin, IGFBP-1 and IGFBP-2 were combined, the ROC-AUC reached 0.87 for women and 0.79 for men, higher than for BMI alone.

Conclusion

Differences were observed comparing adipocyte- and hepatocyte-derived biomarkers in forecasting AGT in NGT subjects. In women the strongest predictor for T2D was adiponectin and in men IGFBP-1, and for prediabetes IGFBP-2 in women and IGFBP-1 in men.

IGF-I and IGFBP-1 in Relation to Body Composition and Physical Performance in Female Olympic Athletes

INTRODUCTION

Insulin- like growth factor-I (IGF-I) is an anabolic hormone that may affect athletic performance in female athletes, and insulin-like growth factor binding protein-1 (IGFBP-1) is an important regulator of bioactive IGF-I. There is limited knowledge of the role of endogenous IGF-I and IGFBP-1 for body composition and physical performance in female elite athletes.

PURPOSE

To examine IGF-I, age adjusted IGF-I (IGFSD), IGFBP-1 and insulin in female Olympic athletes compared with controls and different sport categories, and in relation to body composition and physical performance in the athletes.

METHODS

Female athletes (n=103) and untrained controls (n=113) were included in this cross-sectional study. Body composition was established by dual-energy X-ray absorptiometry. Serum IGF-I and IGFBP-1 were analyzed by radioimmunoassay and IGFSD was calculated. Insulin was analyzed by electrochemiluminescence immunoassay. Athletes were offered to participate in standardized physical fitness tests.

RESULTS

The athletes demonstrated significantly higher IGF-I, IGFSD and IGFBP-1 and lower insulin levels than controls (p<0.05, p<0.05, p<0.01, p<0.001 respectively). Power athletes had significantly higher IGFSD compared to both endurance and technical athletes (p<0.05, p<0.01, respectively). In athletes and controls combined, significant positive correlations were found between IGF variables and higher bone mineral density (BMD) and lean mass and lower fat percent. IGF-I was positively correlated with squat jump (r_s = 0.28, p<0.05) and IGFBP-1 correlated positively with squats (r_s =0.35, p<0.05).

CONCLUSION

We found higher IGF-I, IGFSD and IGFBP-1 in female athletes than controls, and the highest IGFSD in power athletes. IGF-I and IGFBP-1 were related to increased BMD and lean mass and lower fat percent, as well as were positively associated with physical fitness tests. Future studies are needed to elucidate if these results reflect adaptive responses to physical activity or genetic predisposition.

Predictors of normalized HbA1c after gastric bypass surgery in subjects with abnormal glucose levels, a 2-year follow-up study

Clinical biomarkers can predict normalization of HbA1c after Roux-en-Y gastric bypass (RYGB) surgery, but it is unclear which are the most predictive.The aim of this study was to compare biomarkers for insulin sensitivity and other clinical parameters in the prediction of normalization of HbA1c after RYGB surgery. This study included 99 (23 men) obese subjects (BMI > 35 kg/m²) undergoing a laparoscopic RYGB. Clinical and biochemical examinations were performed pre-operatively and up to 2 years after surgery. Pre-operatively, normal fasting glucose levels were found in 25 individuals (NG), prediabetes in 46 and type 2 diabetes (T2DM) in 28. At baseline IGF-I (SD), IGFBP-1 and adiponectin levels were low while leptin was high. Weight loss was observed in all three groups, most in the prediabetes group. After 2 years HbA1c was decreased in prediabetes and T2DM. In all three groups insulin, HOMA-IR, lipids and blood pressure improved, IGFBP-1 and adiponectin increased and leptin decreased. IGF-I (SD) increased only in T2DM. In those with prediabetes or T2DM (n = 74), HbA1c at 2 years correlated to baseline BMI (r = -0.27, p = 0.028), age (r = 0.43, p < 0.001), HbA1c (r = 0.37, p = 0.001) and IGFBP-1 (r = 0.25, p = 0.038), and was normalized in 45/74 (61%) at 1 year and in 36 subjects (49%) at 2 years. These responders were younger, had higher BMI, larger waist circumference, lower HbA1c and lower IGFBP-1 levels at baseline. In a multiple regression model age (negative, p = 0.021) and waist circumference (positive, p = 0.047) were the only predictors for normalized HbA1c. RYGB normalized HbA1c in 49% at two years follow-up, which was predicted by low baseline IGFBP-1 level, a marker of hepatic insulin sensitivty and insulin secretion. However,. younger age and larger waist circumference were the only predictors of normalized HbA1c in multivariate analysis.

Liver nucleotide biosynthesis is linked to protection from vascular complications in individuals with long-term type 1 diabetes

Identification of biomarkers associated with protection from developing diabetic complications is a prerequisite for an effective prevention and treatment. The aim of the present study was to identify clinical and plasma metabolite markers associated with freedom from vascular complications in people with very long duration of type 1 diabetes (T1D). Individuals with T1D, who despite having longer than 30 years of diabetes duration never developed major macro- or microvascular complications (non-progressors; NP) were compared with those who developed vascular complications within 25 years from diabetes onset (rapid progressors; RP) in the Scandinavian PROLONG (n = 385) and DIALONG (n = 71) cohorts. The DIALONG study also included 75 healthy controls. Plasma metabolites were measured using gas and/or liquid chromatography coupled to mass spectrometry. Lower hepatic fatty liver indices were significant common feature characterized NPs in both studies. Higher insulin sensitivity and residual ß-cell function (C-peptide) were also associated with NPs in PROLONG. Protection from diabetic complications was associated with lower levels of the glycolytic metabolite pyruvate and APOCIII in PROLONG, and with lower levels of thiamine monophosphate and erythritol, a cofactor and intermediate product in the pentose phosphate pathway as well as higher phenylalanine, glycine and serine in DIALONG. Furthermore, T1D individuals showed elevated levels of picolinic acid as compared to the healthy individuals. The present findings suggest a potential beneficial shunting of glycolytic substrates towards the pentose phosphate and one carbon metabolism pathways to promote nucleotide biosynthesis in the liver. These processes might be linked to higher insulin sensitivity and lower liver fat content, and might represent a mechanism for protection from vascular complications in individuals with long-term T1D.

Associations of physical activity and sedentary behavior with cardiometabolic biomarkers in prediabetes and type 2 diabetes: a compositional data analysis

Objectives: To investigate the associations between objectively measured sedentary behavior (SB), light-intensity physical activity (LIPA) and moderate-to-vigorous physical activity (MVPA) and cardiometabolic and endocrine biomarkers, and to estimate the associations of reallocating time from one behavior to another with cardiometabolic and endocrine biomarkers.Methods: Baseline data from participants diagnosed with prediabetes or type 2 diabetes, n = 175, 58% men, mean (SD) age = 64.4 (7.7), recruited to a physical activity intervention was used. Time spent in SB, LIPA and MVPA was measured by accelerometer and transformed into isometric log-ratio coordinates. The associations between time spent in SB, LIPA and MVPA and biomarkers were examined by linear regression models. The change in each outcome of reallocating time between the three behaviors was estimated.Results: The findings show strong positive associations of time spent in MVPA and negative associations of time spent in SB relative to time spent in the other behaviors with sagittal abdominal diameter (SAD) and homeostasis model assessment for insulin resistance (HOMA-IR) and negative associations of time spent in SB with high-density lipoprotein (HDL) cholesterol. Theoretically, reallocation of 19 minutes MVPA to SB or to LIPA was associated with a 17% and 17% larger SAD, 39% and 36% larger HOMA-IR values and 3.3% and 2.3% lower levels of HDL, respectively.Conclusion: In conclusion, our analysis from a time-use perspective supports the current evidence that sedentary time is devastating for the cardiometabolic health. While LIPA probably requires more time, maintaining or increasing time in MVPA are the most important features of the time use behaviors when promoting a favorable cardiometabolic risk profile in adults with prediabetes and type 2 diabetes.Trial registration: ClinicalTrials.gov, NCT02374788. Registered 2 March 2015 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02374788.

Effects of drospirenone and norethisterone acetate combined with estradiol on mammographic density and proliferation of breast epithelial cells-A prospective randomized trial

OBJECTIVE

There are no previous data on the influence of drospirenone (DRSP) in combination with estradiol (E2) on the breast in postmenopausal women. The objective of this study was to evaluate the effect of DRSP or norethisterone acetate (NETA) in continuous combination with E2 on two surrogate markers for breast cancer - mammographic breast density and proliferation of breast epithelial cells - in healthy postmenopausal women.

STUDY DESIGN

120 healthy, naturally postmenopausal women were randomized to either 2 mg of DRSP or 0.5 mg of NETA in continuous combination with 1 mg of oral E2. The women underwent mammography and fine-needle aspiration biopsy of the breast at baseline and after six months of treatment.

MAIN OUTCOME MEASURES

Digitized mammographic breast density and breast cell proliferation.

RESULTS

There was a significant increase in mammographic breast density after treatment in both groups (median increase 5.5% for E2/DRSP and 2.3% for E2/NETA, respectively, p < 0.001), but with no significant difference between groups. The proliferation of breast epithelial cells also increased in both groups (p < 0.001, respectively), with a significantly larger increase in the E2/DRSP group than in the E2/NETA group (2.5% versus 0.7%, respectively, p < 0.05). Systolic blood pressure had decreased significantly after 6 months of treatment in the E2/DRSP group (p < 0.05) but not in the E2/NETA group.

CONCLUSIONS

Breast density increased to a similar degree with E2/DRSP and E2/NETA. Proliferation of breast epithelial cells also increased significantly in both groups but was slightly more pronounced in the E2/DRSP group.

Elevated levels of insulin-like growth factor-binding protein 1 predict outcome after acute myocardial infarction: A long-term follow-up of the glucose tolerance in patients with acute myocardial infarction (GAMI) cohort

OBJECTIVE

To investigate the long-term prognostic value of insulin-like growth factor-binding protein 1 in patients with acute myocardial infarction.

METHODS

Patients ( n = 180) with admission glucose < 11 mmol/L without previously known diabetes admitted for an acute myocardial infarction in 1998-2000 were followed for mortality and cardiovascular events (first of cardiovascular mortality/acute myocardial infarction/stroke/severe heart failure) until the end of 2011 (median 11.6 years). Fasting levels of insulin-like growth factor-binding protein 1 at day 2 were related to outcome in Cox proportional hazard regression analyses.

RESULTS

Median age was 64 years, 69% were male and median insulin-like growth factor-binding protein 1 was 20 µg/L. Total mortality was 34% ( n = 61) and 44% ( n = 80) experienced a cardiovascular event during a median follow-up time of 11.6 years. After age adjustment, insulin-like growth factor-binding protein 1 was associated with all-cause (1.40; 1.02-1.93, p = 0.039) and cancer mortality (2.09; 1.15-3.79, p = 0.015) but not with cardiovascular death ( p = 0.29) or cardiovascular events ( p = 0.57). After adjustments also for previous myocardial infarction, previous heart failure and body mass index, insulin-like growth factor-binding protein 1 was still associated with all-cause mortality (1.38; 1.01-1.89, p = 0.046).

CONCLUSION

In patients with acute myocardial infarction without previously known diabetes, high insulin-like growth factor-binding protein 1 was associated with long-term all-cause and cancer mortality but not with cardiovascular events.

Postnatal Changes in Testicular Position Are Associated With IGF-I and Function of Sertoli and Leydig Cells

CONTEXT

Despite clinical guidelines calling for repetitive examination of testicular position during childhood, little is known of normal changes in testicular position during childhood, let alone factors that control it.

OBJECTIVE

To assess changes in and factors associated with testicular position during childhood.

DESIGN

Testicular position (the distance from the pubic bone to the upper pole of the testes) at birth, 3 months, 18 months, 36 months, and 7 years and reproductive hormones at 3 months were measured.

SETTING

Prenatally recruited, prospective longitudinal birth cohort.

PARTICIPANTS

A total of 2545 boys were recruited prenatally in a Danish-Finnish birth cohort and had a testicular position examination available. A subset of 680 Danish and 362 Finnish boys had serum reproductive hormone concentrations and insulin-like growth factor I (IGF-I) determined at 3 months.

MAIN OUTCOME MEASURES

Testicular distance to pubic bone (TDP), serum reproductive hormone, and IGF-I concentrations.

RESULTS

TDP increased from birth to 3 months and decreased thereafter. Length, gestational age, weight for gestational age, and penile length were positively associated with larger TDP and thus lower testicular position in a linear mixed-effect model. Furthermore, IGF-I concentration, inhibin B/follicle-stimulating hormone ratio, and testosterone/luteinizing hormone ratio were all independently and positively associated with longer TDP.

CONCLUSIONS

We provide longitudinal data on postnatal changes in TDP. TDP is dynamic and associated with Leydig and Sertoli cell function as well as with IGF-I levels during the first months of life at mini-puberty of infancy. TDP may thus be a useful biomarker of postnatal testicular function.

Deficiency of liver-derived insulin-like growth factor-I (IGF-I) does not interfere with the skin wound healing rate

Objective

IGF-I is a growth factor, which is expressed in virtually all tissues. The circulating IGF-I is however derived mainly from the liver. IGF-I promotes wound healing and its levels are decreased in wounds with low regenerative potential such as diabetic wounds. However, the contribution of circulating IGF-I to wound healing is unknown.

Here we investigated the role of systemic IGF-I on wound healing rate in mice with deficiency of liver-derived IGF-I (LI-IGF-I-/- mice) during normal (normoglycemic) and impaired wound healing (diabetes).

Methods

LI-IGF-I-/- mice with complete inactivation of the IGF-I gene in the hepatocytes were generated using the Cre/loxP recombination system. This resulted in a 75% reduction of circulating IGF-I. Diabetes was induced with streptozocin in both LI-IGF-I-/- and control mice. Wounds were made on the dorsum of the mice, and the wound healing rate and histology were evaluated. Serum IGF-I and GH were measured by RIA and ELISA respectively. The expression of IGF-I, IGF-II and the IGF-I receptor in the skin were evaluated by qRT-PCR. The local IGF-I protein expression in different cell types of the wounds during wound healing process was analyzed using immunohistochemistry.

Results

The wound healing rate was similar in LI-IGF-I-/- mice to that in controls. Diabetes significantly delayed the wound healing rate in both LI-IGF-I-/- and control mice. However, no significant difference was observed between diabetic animals with normal or reduced hepatic IGF-I production. The gene expression of IGF-I, IGF-II and IGF-I receptor in skin was not different between any group of animals tested. Local IGF-I levels in the wounds were similar between of LI-IGF-I-/- and WT mice although a transient reduction of IGF-I expression in leukocytes in the wounds of LI-IGF-I-/- was observed seven days post wounding.

Conclusion

Deficiency in the liver-derived IGF-I does not affect wound healing in mice, neither in normoglycemic conditions nor in diabetes.

IGFBP-1 and IGF-I as markers for advanced fibrosis in NAFLD - a pilot study

BACKGROUND AND AIMS

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease globally. Advanced fibrosis (stage 3-4) is the most robust marker for future mortality, but diagnosis requires liver biopsy. Current non-invasive scoring systems aimed to identify advanced fibrosis are imperfect. Insulin-like growth factor I (IGF-I) and its binding protein IGFBP-1 are liver derived proteins, that are involved in various liver disorders. The aim of this study was to examine the possible association between advanced fibrosis and IGF-I and IGFBP-1 in NAFLD.

METHODS

Fasting blood samples were obtained from 52 patients diagnosed with NAFLD by liver biopsy. Total IGF-I and IGFBP-1 concentrations were determined in serum by in-house radio-immuno-assays. IGF-I levels were age-standardized (IGF-SD). A logistic regression model was used to investigate the association of IGF-SD and IGFBP-1 with advanced fibrosis (stage 3-4).

RESULTS

Patients with advanced fibrosis (stage 3-4 vs. 0-2) had lower IGF-SD (-1.17 vs. 0.11, p = .01) and higher mean levels of IGFBP-1 (29.9 vs. 18.8 µg/l, p = .02). IGFBP-1 was associated with presence of advanced fibrosis (OR 1.04 per unit increase, 95%CI 1.0-1.07, p = .05), while IGF-1 was negatively associated with advanced fibrosis (OR 0.63 per standard deviation, 95%CI 0.44-0.92, p = .02).

CONCLUSIONS

This pilot study suggests an association between serum IGFBP-1 and IGF-I levels with advanced fibrosis in NAFLD patients. IGFBP1 and IGF-1 could be of interest as future biomarkers. Similar studies in larger cohorts are needed.

Association of IGF-1 with coronary collateral circulation in stable coronary artery disease

Aim: The aim of the present study is to evaluate the relationship between coronary collateral circulation (CCC) grade and serum IGF-1 levels in patients diagnosed with stable coronary artery disease. Methods: Totally, 190 consecutive patients with stable coronary artery disease who underwent coronary angiography were included in this study. Results: The patients with good CCC had significantly higher IGF-1 levels compared with the poor ones. On the contrary, hs-CRP was significantly lower in the good CCC group. We also demonstrated that IGF-1 level was significantly related with the grade of CCC. Conclusion: We believe that measurement of IGF-1 level may help clinicians for predicting CCC development.

Increase in insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 1 after supplementation with selenium and coenzyme Q10. A prospective randomized double-blind placebo-controlled trial among elderly Swedish citizens

Background

Insulin-like growth factor-1(IGF-1) has a multitude of effects besides cell growth and metabolism. Reports also indicate anti-inflammatory and antioxidative effects. The concentrations of IGF-1 decrease with age and during inflammation. As selenium and coenzyme Q10 are involved in both the antioxidative defense and the inflammatory response, the present study aimed to examine the effects of supplementation with selenium and coenzyme Q10 on concentrations of IGF-1 and its binding protein IGFBP-1 in a population showing reduced cardiovascular mortality following such supplementation.

Methods

215 elderly individuals were included and given the intervention for four years. A clinical examination was performed and blood samples were taken at the start and after 48 months. Evaluations of IGF-1, the age adjusted IGF-1 SD score and IGFBP-1 were performed using group mean values, and repeated measures of variance.

Findings

After supplementation with selenium and coenzyme Q10, applying group mean evaluations, significantly higher IGF-1 and IGF-1 SD scores could be seen in the active treatment group, whereas a decrease in concentration could be seen of the same biomarkers in the placebo group.

Applying the repeated measures of variance evaluations, the same significant increase in concentrations of IGF-1 (F = 68; P>0.0001), IGF-1 SD score (F = 29; P<0.0001) and of IGFBP-1 (F = 6.88; P = 0.009) could be seen, indicating the effect of selenium and coenzyme Q10 also on the expression of IGF-1 as one of the mechanistic effects of the intervention.

Conclusion

Supplementation with selenium and coenzyme Q10 over four years resulted in increased levels of IGF-1 and the postprandial IGFBP-1, and an increase in the age-corrected IGF-1 SD score, compared with placebo. The effects could be part of the mechanistic explanation behind the surprisingly positive clinical effects on cardiovascular morbidity and mortality reported earlier. However, as the effects of IGF-1 are complex, more research on the result of intervention with selenium and coenzyme Q10 is needed.

High Serum Insulin-Like Growth Factor-Binding Protein 1 (IGFBP-1) is Associated with High Fracture Risk Independent of Insulin-Like Growth Factor 1 (IGF-I)

High serum levels of IGFBP-1 are related both to low body mass index (BMI) and to low insulin-like growth factor 1 (IGF-I), which both in turn are related to low bone mineral density (BMD) and to increased fracture risk. However, we have found no previous prospective studies on IGFBP-1 and fracture risk. Despite its name, IGFBP-1 is not only just a binding protein but also has its own IGF-independent effects, e.g., stimulating osteoclast differentiation. IGFBP-1 might have an IGF-related and/or an IGF-independent association to fracture risk. This is a population-based prospective cohort study with a ten-year follow-up of 351 women aged 69-79 at inclusion. Fracture and mortality data were collected from national health care registers. IGFBP-1 had a positive linear relation to the risk of both hip fractures and "major osteoporotic fractures" including fractures of the hip, spine, shoulder, and wrist. The age-adjusted hazard ratio (HR) for a hip fracture was 1.46 (95 % CI 1.08-1.99) for one SD increase in IGFBP-1. The corresponding age-adjusted HR for major osteoporotic fractures was 1.33 (95 % CI 1.05-1.69). The relation between IGFBP-1 and fracture risk was not confounded by either IGF-I or BMI. Femoral neck BMD, however, mediated 56 % of the total "effect" of IGFBP-1 on hip fracture risk. In conclusion, IGFBP-1 had a positive linear relation to fracture risk, partly mediated by BMD but not related to IGF-I or BMD. This implies that IGFBP-1 might be an important factor in bone turnover and that further studies on this would be valuable.

Effects of prenatal micronutrient and early food supplementation on metabolic status of the offspring at 4.5 years of age. The MINIMat randomized trial in rural Bangladesh

Background: Fetal nutritional insults may alter the later metabolic phenotype. We hypothesized that early timing of prenatal food supplementation and multiple micronutrient supplementation (MMS) would favourably influence childhood metabolic phenotype.

Methods: Pregnant women recruited 1 January to 31 December 2002 in Matlab, Bangladesh, were randomized into supplementation with capsules of either 30 mg of iron and 400 μg of folic acid, 60 mg of iron and 400 μg of folic acid, or MMS containing a daily allowance of 15 micronutrients, and randomized to food supplementation (608 kcal) either with early invitation (9 weeks’ gestation) or usual invitation (at 20 weeks). Their children (n = 1667) were followed up at 4.5 years with assessment of biomarkers of lipid and glucose metabolism, inflammation and oxidative stress.

Results: Children in the group with early timing of food supplementation had lower cholesterol (difference -0.079 mmol/l, 95% confidence interval (CI) -0.156; -0.003), low-density lipoprotein (LDL) (difference -0.068 mmol/l, 95% CI -0.126; -0.011) and ApoB levels (difference -0.017 g/l, 95% CL -0.033; -0.001). MMS supplementation resulted in lower high-density lipoprotein (HDL) (difference -0.028 mmol/l, 95% CL -0.053; -0.002), lower glucose (difference -0.099 mmol/l, 95% CL -0.179; -0.019) and lower insulin-like growth factor 1 (IGF-1) (difference on log scale -0.141 µg/l, 95% CL -0.254; -0.028) than 60 mg iron and 400 μg folic acid. There were no effects on markers of inflammation or oxidative stress.

Conclusions: Findings suggest that in a population where malnutrition is prevalent, nutrition interventions during pregnancy may modify the metabolic phenotype in the young child that could have consequences for later chronic disease risks.

High-dose atorvastatin is associated with lower IGF-1 levels in patients with type 1 diabetes

INTRODUCTION

Insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 1 (IGFBP-1) play an important role in vascular health. Many patients with type 1 diabetes are medicated with HMG-CoA reductase inhibitors, statins, in order to prevent vascular complications. Yet little is known about the effect of statins on the IGF-1/IGFBP-1 axis in these patients.

OBJECTIVES

The aim of this study was to evaluate the effect of atorvastatin treatment on IGF-1 and IGFBP-1 with regards to microvascular function.

DESIGN

Twenty patients with type 1 diabetes received either placebo or 80mg atorvastatin for two months in a double-blinded cross-over study. IGF-1 and IGFBP-1 levels were assessed before and after each treatment period. Skin microcirculation was studied using Doppler perfusion imaging during iontophoresis of acetylcholine and sodium nitroprusside to assess endothelium-dependent and endothelium-independent microvascular reactivity, respectively.

RESULTS

Treatment with high-dose atorvastatin was associated with a significant decrease in IGF-1 levels compared to placebo (p<0.05, ANOVA repeated measures), whereas no effect was seen on IGFBP-1 or the IGF-1/IGFBP-1 ratio. These variables did not correlate with measurements of skin microvascular reactivity.

CONCLUSIONS

The study found that treatment with high-dose atorvastatin was associated with reduced IGF-1 levels, which may indicate a potential negative effect on microvascular function and long-term risk of microangiopathy development.

Circulating Hepcidin-25 Is Reduced by Endogenous Estrogen in Humans

OBJECTIVE

Hepcidin reduces iron absorption by binding to the intestinal iron transporter ferroportin, thereby causing its degradation. Although short-term administration of testosterone or growth hormone (GH) has been reported to decrease circulating hepcidin levels, little is known about how hepcidin is influenced in human endocrine conditions associated with anemia.

RESEARCH DESIGN AND METHODS

We used a sensitive and specific dual-monoclonal antibody sandwich immunoassay to measure hepcidin-25 in patients (a) during initiation of in vitro fertilization when endogenous estrogens were elevated vs. suppressed, (b) with GH deficiency before and after 12 months substitution treatment, (c) with hyperthyroidism before and after normalization, and (d) with hyperprolactinemia before and after six months of treatment with a dopamine agonist.

RESULTS

In response to a marked stimulation of endogenous estrogen production, median hepcidin levels decreased from 4.85 to 1.43 ng/mL (p < 0.01). Hyperthyroidism, hyperprolactinemia, or GH substitution to GH-deficient patients did not influence serum hepcidin-25 levels.

CONCLUSIONS

In humans, gonadotropin-stimulated endogenous estrogen markedly decreases circulating hepcidin-25 levels. No clear and stable correlation between iron biomarkers and hepcidin-25 was seen before or after treatment of hyperthyroidism, hyperprolactinemia or growth hormone deficiency.

Improved glycemic control due to sitagliptin is not related to cortisol or the surrogate marker IGFBP-1 for hepatic insulin sensitivity

IMPORTANCE

Elevated cortisol levels and dysregulated insulin-like growth factor binding protein-1 (IGFBP-1; a marker of hepatic insulin sensitivity) are both related to insulin resistance and glucose abnormalities. It is unknown whether improvement in these parameters is related to improved glucose metabolism during treatment with sitagliptin.

OBJECTIVE

To determine whether improved insulin sensitivity and beta-cell function during treatment with sitagliptin is related to lower cortisol levels and/or improved regulation of IGFBP-1 in patients with recent acute coronary syndrome (ACS) and newly discovered glucose abnormalities.

DESIGN

Samples were taken from The BEta-cell function in Glucose abnormalities and Acute Myocardial Infarction (BEGAMI) trial, a double-blinded, placebo-controlled randomized clinical trial on the efficacy and safety of sitagliptin for patients with ACS and newly discovered glucose abnormalities.

SETTING

Cardiology departments (cardiac ICU and outpatient clinic) in two hospitals in Stockholm, Sweden.

PARTICIPANTS

Subjects hospitalized (or recently hospitalized) for ACS, in whom an oral glucose tolerance test revealed previously unknown glucose abnormalities.

INTERVENTIONS

Subjects were randomized to sitagliptin 100mg once daily (n=34) or placebo (n=37) for twelve weeks. Oral glucose tolerance test (OGTT) and randomization occurred after stabilization median 7 days after ACS.

MAIN OUTCOMES AND MEASURES

Fasting serum cortisol and IGFBP-1 were analyzed before OGTT, around 8a.m., and after at 10a.m. The latter time point was chosen as the spread in cortisol levels around is small then, allowing improved chances to detect differences between groups.

RESULTS

Glucose tolerance and insulin sensitivity improved in both groups, while HbA1c and indices of β-cell function improved only in the sitagliptin group as reported previously. Both groups displayed decreased cortisol levels around 10a.m. (from 338±21 to 278±14 nmol/L, p=0.038, in the sitagliptin group; from 343±17 to 302±15 nmol/L, p=0.017, in the placebo group), and improved correlation between fasting log-IGFBP-1 and insulin.

CONCLUSIONS AND RELEVANCE

These findings suggest that a stress-related elevation in cortisol may have negative impact on glucose tolerance in patients with recent ACS. However, improved glycemic control with sitagliptin does not appear to be related to changes in cortisol levels or hepatic insulin sensitivity as assessed by IGFBP-1.

Biomarkers of nutrition and stress in pregnant women with a history of eating disorders in relation to head circumference and neurocognitive function of the offspring

Background

Eating disorders during pregnancy can affect fetal growth and the child’s early development, but the underlying mechanisms have not been elucidated. The aim of the present study was to investigate serum biomarkers of nutrition and stress in pregnant women with previous eating disorders compared to controls and in relation to head circumference and early neurocognitive development of the offspring.

Methods

In a longitudinal cohort study, pregnant nulliparous non-smoking women with a history of anorexia nervosa (n = 20), bulimia nervosa (n = 17) and controls (n = 59) were followed during pregnancy and their children’s growth and neurocognitive development were followed up to five years of age. We investigated maternal serum biomarkers of nutrition and stress (ferritin, cortisol, thyroid-stimulating hormone, free thyroxine, insulin, insulin-like growth factor I (IGF-I) and IGF binding protein 1) in blood samples collected during early pregnancy and compared between groups (ANOVA, LSD post-hoc test). The results were related to previous data on head circumference at birth and neurocognitive development at five years of age of the offspring (Spearman rank correlation or Pearson correlation test).

Results

Serum levels of ferritin in the women with previous anorexia nervosa, but not in those with a history of bulimia nervosa, were significantly lower than in the controls (p < 0.01), and correlated strongly to impaired memory function in their children (rs = −0.70, p < 0.001). Maternal serum levels of free thyroxine were similar between groups but correlated positively to reduced head circumference at birth of the children in the bulimia nervosa group (r = 0.48, p < 0.05), and with the same tendency in the anorexia nervosa group (r = 0.42, p = 0.07), but not in the controls (r = 0.006). There were no significant differences in cortisol or the other biomarkers between groups.

Conclusions

Low maternal serum ferritin in women with previous anorexia nervosa may be of importance for impaired memory capacity in the offspring at five years of age. Our results also indicate that thyroxin levels in pregnant women with previous eating disorders are positively associated with fetal head growth.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-015-0741-7) contains supplementary material, which is available to authorized users.

Effects of protein-rich nutritional supplementation and bisphosphonates on body composition, handgrip strength and health-related quality of life after hip fracture: a 12-month randomized controlled study

BACKGROUND

The catabolic state that follows hip fracture contributes to loss of muscle mass and strength, that is sarcopenia, which impacts functional ability and health-related quality of life. Measures to prevent such long-term postoperative consequences are of important concern. The aim of this study was to evaluate the combined effects of protein-rich nutritional supplementation and bisphosphonate on body composition, handgrip strength and health-related quality of life following hip fracture.

METHODS

The study included 79 men and women with hip fracture, mean age 79 years (SD 9), without severe cognitive impairment, who were ambulatory and living independently before fracture. Patients were randomized postoperatively to receive liquid supplementation that provided 40 g of protein and 600 kcal daily for six months after the fracture, in addition to bisphosphonates once weekly for 12 months (group N, n = 26), or bisphosphonates alone once weekly for 12 months (group B, n = 28). All patients, including the controls (group C, n = 25) received calcium 1 g and vitamin D3 800 IU daily. Body composition as measured by dual-energy X-ray absorptiometry (DXA), handgrip strength (HGS) and health-related quality of life (HRQoL) were registered at baseline, six and 12 months postoperatively.

RESULTS

There were no differences among the groups regarding change in fat-free mass index (FFMI), HGS, or HRQoL during the study year. Intra-group analyses showed improvement of HGS between baseline and six months in the N group (P = 0.04). HRQoL decreased during the first year in the C and B groups (P = 0.03 and P = 0.01, respectively) but not in the nutritional supplementation N group (P = 0.22).

CONCLUSIONS

Protein-rich nutritional supplementation was unable to preserve FFMI more effectively than vitamin D and calcium alone, or combined with bisphosphonate, in this relatively healthy group of hip fracture patients. However, trends toward positive effects on both HGS and HRQoL were observed following nutritional supplementation.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01950169 (Date of registration 23 Sept 2013).

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.

Gender difference in adrenal sensitivity to ACTH is abolished in type 2 diabetes

OBJECTIVE

Dysfunction of the hypothalamus-pituitary-adrenal (HPA) axis has been implicated in type 2 diabetes (T2D). The aim of this study was to investigate the impact of T2D and gender on the HPA axis.

METHODS

Synthetic ACTH (1 μg) was administered to 21 subjects with T2D (age 62 (54-70) years, 11 men/ten women, HbA1c 49±2 mmol/mol, treated with diet or oral antidiabetic drugs) and 38 controls (age 58 (41-67) years, 20 men/18 women). Fasting basal B-glucose, serum cortisol, insulin, IGF1 and IGFBP1 concentrations were measured, and sampling for all but IGF1 was repeated 30, 60, and 90 min after ACTH injection. Patients took 0.25 mg dexamethasone at 2200-2300 h and returned the next morning for the measurement of serum cortisol concentration.

DESIGN

Cross-sectional study.

RESULTS

Patients with T2D had similar fasting serum cortisol, IGF1 and IGFBP1 concentrations; however, serum cortisol concentration after administration of dexamethasone did not differ between the groups. Healthy women exhibited higher peak cortisol levels compared with healthy men (675±26 vs 582±21 nmol/l, P=0.014), while the peak levels were equally high in men and women with T2D, resulting in a higher peak level in men with T2D compared with healthy men (691±42 vs 582±21 nmol/l, P=0.024). Serum cortisol concentration after administration of dexamethasone did not differ between the groups, nor did IGF1 and IGFBP1.

NOVELTY OF THE FINDINGS

Some studies have previously indicated disturbed regulation of the hypothalamus-pituitary-adrenal (HPA) axis in subjects with type 2 diabetes (T2D); however, much remains unknown in this area. To the best of our knowledge, this is the first study to show that the gender difference in the adrenal response to ACTH (with greater reactivity in women) is abolished in T2D. While the clinical implications cannot be determined by this paper, it is known that gender differences exist in the pathogenesis and complications of T2D. Thus, our findings suggest that further research into gender differences in the HPA axis is warranted.

CONCLUSIONS

Gender differences in adrenal response to ACTH were abolished in T2D. Men with T2D had a higher peak cortisol compared with controls. Further studies are needed to elucidate the clinical implications.

Free dissociable IGF-I: Association with changes in IGFBP-3 proteolysis and insulin sensitivity after surgery

BACKGROUND

Patients receiving a carbohydrate drink (CHO) before major abdominal surgery display improved insulin sensitivity postoperatively and increased proteolysis of IGFBP-3 (IGFBP-3-PA) compared to patients undergoing similar surgery after overnight fasting.

AIMS

We hypothesized that serum IGFBP-3-PA increases bioavailability of circulating IGF-I and preserves insulin sensitivity in patients given CHO.

DESIGN

Matched control study.

METHODS

At Karolinska University Hospital, patients given CHO before major elective abdominal surgery (CHO,n = 8) were compared to patients undergoing similar surgical procedures after overnight fasting (FAST,n = 10). Results from two different techniques for determination of free-dissociable IGF-I (fdIGF-I) were compared with changes in IGFBP-3-PA and insulin sensitivity.

RESULTS

Postoperatively, CHO displayed 18% improvement in insulin sensitivity (hyperinsulinemic clamp) and increased IGFBP-3-PA vs. FAST. As determined by IRMA, fdIGF-I increased by 48 ± 25% in CHO while fdIGF-I decreased by 13 ± 18% in FAST (p < 0.01 vs. CHO, when corrected for duration of surgery). However, fdIGF-I determined by ultra-filtration decreased similarly in both groups (-22 ± 8% vs. -25 ± 8%, p = 0.8) and IGFBP-1 increased similarly in both groups. Patients with less insulin resistance after surgery demonstrated larger increases in fdIGF-I by IRMA (r = 0.58, p < 0.05). Fifty-three % of the variability of the changes in fdIGF-I by IRMA could be explained by changes in IGFBP-3-PA and total IGF-I levels (p < 0.05), while IGFBP-1 did not contribute significantly.

CONCLUSION

During conditions when serum IGF-I bioavailability is regulated by IGFBP-3 proteolysis, measurements of fdIGF-I by IRMA is of physiological relevance as it correlates with the associated changes in insulin sensitivity.

Growth hormone treatment improves vitality and behavioural issues in children with Prader-Willi syndrome

AIM

Prader-Willi syndrome is a neurogenetic disorder, with characteristics such as obesity, short stature, muscular weakness, intellectual deficiencies and deviant social behaviour. This study evaluated whether growth hormone treatment of children with Prader-Willi syndrome resulted in possible and lasting effects on their cognition and behaviour.

METHODS

We randomised six girls and 13 boys to either a treatment group or a control group. The treatment group received growth hormone (Genotropin(®) 0.033 mg/kg/day) for 2 years, while the control group did not receive treatment in the first year and then received a double dose in the second year. Treatment was then stopped in both groups for 6 months.

RESULTS

Both groups showed the same intellectual disabilities at the start of the study, and no difference was found after the first and second years. The parents reported that the children showed increased vitality during treatment. When treatment was stopped, the children showed a marked exacerbation of behavioural problems, a significant increase in body fat and a decrease in insulin-like growth factor 1 levels.

CONCLUSION

We believe this is the first study to show that abrupt-ceasing growth hormone treatment led to a successive deterioration in behavioural problems in children with Prader-Willi syndrome.

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.

Metabolomics: a tool for the diagnosis of GH deficiency and for monitoring GH replacement?

The diagnostic value of insulin-like growth factor 1 (IGF1) for GH deficiency (GHD) in adults is not optimal. Molecular profiling could be used for biomarker discovery. The aim of this pilot study was to compare the serum metabolome between GHD patients and healthy controls, and identification of potential markers for diagnosis and/or for individual GH dosing. A total of ten patients with GHD, median age of 55 years and BMI of 27 kg/m(2), were compared with ten healthy age- and gender-matched controls. The serum metabolic profiles were generated using gas chromatography-coupled mass spectroscopy on fasting samples taken in the morning from the controls and at baseline and during 6 months of GH replacement in the patients with GHD. The difference in low-molecular weight compounds (LMC) distinguished the healthy controls from GHD patients. Among 285 measured metabolites, 13 were identified as being most important in differentiating GHD patients from controls. Of these, 11 could not be structurally annotated but many were classified as lipids. The difference in the LMC pattern persisted despite normalisation of IGF1 following GH replacement. GH replacement increased the levels of specific fatty acid compounds and decreased the levels of certain amino acids. No metabolite changed in response to GH treatment, to the same extent as IGF1. The measurement of 285 metabolites resulted in a unique pattern in GHD, but changes in the metabolite patterns during GH treatment were limited. The utility of metabolomics to find new markers in GHD and GH replacement remains to be further elucidated.

Epigenetic analyses of the insulin-like growth factor binding protein 1 gene in type 1 diabetes and diabetic nephropathy

Background

Clinical observations have demonstrated that high levels of circulating insulin-like growth factor binding protein-1 (IGFBP-1) are associated with type 1 diabetes (T1D), whereas low serum IGFBP-1 levels are associated with the risk of type 2 diabetes (T2D). Recently, we reported that increased DNA methylation levels in the IGFBP1 gene were associated with T2D. In the present study, we evaluated the epigenetic changes of IGFBP1 in T1D and diabetic nephropathy (DN).

Results

In total, 778 Swedish individuals, including T1D patients with or without DN and subjects with the normal glucose tolerance (NGT), were involved in the study. IGFBP1 methylation levels in genomic DNA extracted from peripheral blood were analyzed with bisulfite pyrosequencing. Serum IGFBP-1 levels were measured with radioimmunoassay. We found that DNA methylation levels in the IGFBP1 gene were decreased (15.6% versus 16.9%; P < 0.001), whereas serum IGFBP-1 levels were increased (31 versus 24 μg/L, P = 0.003) in T1D patients compared with NGT subjects. Furthermore, T1D patients with DN had increased circulating IGFBP-1 concentration compared with the patients without DN (52 versus 28 μg/L; P = 0.006). However, no difference of the IGFBP1 DNA methylation levels between T1D patients with and without DN was observed.

Conclusions

This study shows for the first time that T1D patients had decreased DNA methylation levels in the IGFBP1 gene and further implies that increased circulating IGFBP-1 levels are associated with T1D and DN.

Gender differences in non-glycemic responses to improved insulin sensitivity by pioglitazone treatment in patients with type 2 diabetes

Excess cortisol and GH induce insulin resistance, a central feature of type 2 diabetes (T2D). To study whether the insulin sensitizer pioglitazone affects basal cortisol levels and the GH-IGF-I axis in patients with T2D. Forty-eight patients with T2D (men/women = 28:20, age 61 ± 1 years, BMI 31 ± 0.6 kg/m(2)) were treated for 26 weeks with pioglitazone 30-45 mg daily in addition to their preexisting therapy. Insulin, proinsulin, HbA(1c), IGF-I, IGFBP-1, and basal cortisol were analyzed before and after treatment. Pioglitazone decreased proinsulin/insulin ratio and HbA(1c) decreased (HbA(1c) from 7.8 ± 0.2 to 6.6 ± 0.2% in men and from 7.6 ± 0.2 to 6.1 ± 0.2% in women, p < 0.001 in both). There was a redistribution of fat but no change in waist circumference. IGF-I and adiponectin increased (p ≤ 0.001) in both genders. IGFBP-1 increased but significantly only for the whole group (p = 0.033). Triglycerides decreased significantly in women only (p = 0.015). Before treatment, women had lower basal cortisol (p = 0.045). Basal cortisol increased in women (from 390 ± 26 to 484 ± 32 nmol/L, p = 0.020) but not in men and did not differ between genders at week 26. ΔIGFBP-1 correlated with Δcortisol (r = 0.458; p = 0.049) and Δadiponectin (r = 0.600; p = 0.005) in women only. In addition to the known effect of improving insulin sensitivity, pioglitazone increased IGF-I regardless of gender and in women also increased basal cortisol. Increased IGF-I may contribute to improved insulin sensitivity after treatment. There seems to be gender differences in treatment responses to pioglitazone on lipid metabolism and basal cortisol, perhaps correcting different mechanisms of insulin resistance between genders.

Targeted selected reaction monitoring mass spectrometric immunoassay for insulin-like growth factor 1

Insulin-like growth factor 1 (IGF1) is an important biomarker of human growth disorders that is routinely analyzed in clinical laboratories. Mass spectrometry-based workflows offer a viable alternative to standard IGF1 immunoassays, which utilize various pre-analytical preparation strategies. In this work we developed an assay that incorporates a novel sample preparation method for dissociating IGF1 from its binding proteins. The workflow also includes an immunoaffinity step using antibody-derivatized pipette tips, followed by elution, trypsin digestion, and LC-MS/MS separation and detection of the signature peptides in a selected reaction monitoring (SRM) mode. The resulting quantitative mass spectrometric immunoassay (MSIA) exhibited good linearity in the range of 1 to 1,500 ng/mL IGF1, intra- and inter-assay precision with CVs of less than 10%, and lowest limits of detection of 1 ng/mL. The linearity and recovery characteristics of the assay were also established, and the new method compared to a commercially available immunoassay using a large cohort of human serum samples. The IGF1 SRM MSIA is well suited for use in clinical laboratories.

Increased DNA methylation levels of the insulin-like growth factor binding protein 1 gene are associated with type 2 diabetes in Swedish men

Background

Prospective studies have shown that low levels of circulating insulin-like growth factor binding protein-1 (IGFBP-1) are associated with the risk of type 2 diabetes. In the present study, we investigated DNA methylation in the IGFBP1 gene to evaluate its changes in relation to serum IGFBP-1 levels in type 2 diabetes.

Results

A total of 406 Swedish men, including age-matched normal glucose tolerance subjects and type 2 diabetes patients either newly diagnosed or undergoing treatment, were selected from the Stockholm Diabetes Prevention Program. IGFBP1 methylation levels in genomic DNA extracted from peripheral blood were analysed by bisulfite pyrosequencing. Serum IGFBP-1 levels were measured by radio-immunoassay. We found that IGFBP1 DNA methylation levels were higher in both newly diagnosed and treated type 2 diabetes patients with a mean diabetes duration of 3 years compared with subjects with normal glucose tolerance (19.8% and 20.2% vs. 16.9%, P < 0.001 for both). Serum levels of IGFBP-1 in newly diagnosed and in treated type 2 diabetes patients were lower compared with healthy individuals (18 μg/l both vs. 24 μg/l, P = 0.011, P < 0.001). IGFBP1 methylation levels but not serum IGFBP-1 levels in type 2 diabetes patients were independent of body mass index. Newly diagnosed patients with a family history of diabetes (FHD) had higher IGFBP1 methylation levels than those without FHD (20.3% vs. 18.6%, P = 0.017).

Conclusions

This study provides the first evidence that changes in DNA methylation of the IGFBP1 gene are associated with type 2 diabetes in Swedish men and suggests that increased IGFBP1 DNA methylation and decreased IGFBP-1 serum levels are features of type 2 diabetes with a short duration.

Evaluation of IGFBP-7 DNA methylation changes and serum protein variation in Swedish subjects with and without type 2 diabetes

Background

Insulin-like growth factor-binding protein 7 (IGFBP-7) is able to interact with insulin-like growth factor 1 (IGF-1) as well as insulin. Previous studies have suggested that serum IGFBP-7 levels may be associated with insulin resistance in type 2 diabetes (T2D). This study aimed to evaluate IGFBP-7 serum protein and IGFBP7 DNA methylation levels in the subjects with and without T2D.

Results

A total of 340 Swedish subjects including 100 newly diagnosed T2D patients (50 women/50 men), 100 age-matched nondiabetic control subjects (50/50) and 140 treated T2D patients (54/86) were studied. Serum IGFBP-7 levels were measured with a novel ELISA. IGF1, IGFBP-1, and insulin were determined by in-house radioimmunoassays. DNA methylation levels in the IGFBP7 gene were analyzed with a bisulfite-pyrosequencing technique. Serum IGFBP-7 protein levels were similar among nondiabetic subjects, newly diagnosed, and treated T2D patients and were not correlated with IGFBP7 DNA methylation. However, IGFBP7 DNA methylation was increased in men with newly diagnosed T2D compared with nondiabetic controls (17.6% vs. 12.5%, P < 0.01). Serum IGFBP-7 levels correlated (r = 0.331, P = 0.019) with serum IGFBP-1 levels, a marker of insulin production, in men but not women with newly diagnosed T2D.

Conclusions

This study demonstrates for the first time that IGFBP7 DNA methylation levels are increased in Swedish men with newly diagnosed T2D. The correlation between IGFBP-7 and IGFBP-1 suggests that low IGFBP-7 may be associated with insulin resistance in T2D.

Effects of lifestyle on plasma levels of the IGF system and the antioxidants coenzyme Q10 and vitamin E in Kenyan rural and urban populations

OBJECTIVE

Overnight fasting blood plasma insulin-like growth factor-I (IGF-I), insulin-like growth factor binding protein-1 (IGFBP-1), coenzyme Q10, (CoQ) vitamin E and plasma lipids were compared between a semi-nomadic Samburu population and relatively urbanized cohorts from Nairobi, Kenya.

RESEARCH DESIGN AND METHODS

143 middle aged subjects without known diabetes were included. IGF-I and IGFBP-1 were analyzed by RIA, and CoQ and vitamin E by HPLC. Plasma lipid levels were analyzed by standard laboratory methods routinely used in the clinics.

RESULTS

The age adjusted IGF-I serum levels were low in the Samburu male and female populations, ranging from 0 to -4 IGFSD-score (SDS), and a minor part of the investigated population reaching as low as -5 and -7 SDS. The Nairobi cohorts showed significantly higher values reaching from -2.5 to +1 SDS (P<0.0001). The nomadic Samburu population showed fasting IGFBP-1 values ranging from 30-100 μg/l, while that of the urbanized Nairobi cohorts was considerably lower (25-60 μg/l) (P<0.0001). CoQ concentrations of the Nairobi cohorts were 1.5-2.0 nmol/ml similar to the levels found in several European countries. The Samburu population on the other hand showed extremely high CoQ values ranging from 2 to 9 nmol/ml (P<0.0001). Vitamin E levels of the Nairobi group were low (5-20 nmol/ml), but the Samburu population had even lower levels ranging from 3 to 15 nmol/ml (P<0.0001). Plasma lipid levels such as cholesterol, triglycerides, LDL/HDL, ApoB/ApoA ratios as well as BMI and weight were significantly higher in the Nairobi population (P<0.0001).

CONCLUSIONS

Low IGF-I and high IGFBP-1 levels of the Samburu cohorts indicate malnutrition. High lipid levels of the Nairobi cohorts indicate that these groups have several risk factors for cardiovascular diseases and diabetes type2.

Leptin may enhance hepatic insulin sensitivity in children and women born small for gestational age

OBJECTIVE

Children born small for gestational age (SGA) are at risk for developing type 2 diabetes. Lipodystrophy leads to early type 2 diabetes and leptin reverses the metabolic consequences of the disease. Low IGF-binding protein 1 (IGFBP1) can predict the development of type 2 diabetes. The aim of this study was to determine leptin, insulin, and IGFBP1 in children and adult women born preterm or SGA to evaluate the role of leptin as a compensatory mechanism in insulin resistance development.

METHODS

Seventy-six children (8.5-10 years, 41 girls and 35 boys) and 45 women (23-30 years) were studied. The children comprised subjects born appropriate for gestational age (<30 gestational weeks) (n=22), born SGA at term (n=23), and full-term normal-weight controls (n=31). Among the women, the corresponding figures were, n=10, n=18, and n=17 respectively. Fasting levels of IGFBP1, leptin, insulin, and IGF1 were determined and total adiponectin only in women.

RESULTS

In girls and women, term SGA subjects had higher leptin levels in relation to BMI SDS (P=0.042 and P=0.03 respectively). More than half of IGFBP1 variability was explained by leptin and insulin in children. In term SGA women, IGFBP1 level was lower compared with controls (P=0.012) and the regression line of IGFBP1 on insulin was suppressed below -1 s.d. of a reference material.

CONCLUSION

Leptin levels were elevated in term SGA girls and women, in particular in adult women, but not found in preterm girls and women. IGFBP1 was lower in term SGA women. In children, leptin and insulin were strong suppressors of IGFBP1. We speculate that higher leptin levels could be a protective event to enhance hepatic insulin sensitivity.

Bone mineral density, bone markers, and fractures in adult males with congenital adrenal hyperplasia

OBJECTIVE

The aim of this study was to determine bone mineral density (BMD), markers of bone metabolism, fractures, and steroids reflecting hormonal control in adult males with congenital adrenal hyperplasia (CAH). SUBJECTS, METHODS, AND DESIGN: We compared CAH males with 21-hydroxylase deficiency (n=30), 19-67 years old, with age- and sex-matched controls (n=32). Subgroups of CYP21A2 genotypes, age, glucocorticoid preparation, poor control vs overtreatment, and early vs late (>36 months) diagnosis were studied. BMD measured by dual energy X-ray absorptiometry and markers of bone metabolism and androgens/17-hydroxyprogesterone levels were investigated.

RESULTS

All, including older (>30 years), CAH patients had lower BMD in all measured sites compared with control subjects. The null group demonstrated lower BMD in more locations than the other groups. Osteoporosis/osteopenia was present in 81% of CAH patients compared with 32% in controls (≥30 years). Fracture frequency was similar, osteocalcin was lower, and fewer patients than controls had vitamin D insufficiency. IGF1 was elevated in the milder genotypes. In patients, total body BMD was positively correlated to weight, BMI, total lean body mass, and triglycerides, and negatively to prolactin. Patients on prednisolone had lower BMD and osteocalcin levels than those on hydrocortisone/cortisone acetate. Patients with poor control had higher femoral neck BMD. There were no differences in BMD between patients with an early vs late diagnosis.

CONCLUSIONS

CAH males have low BMD and bone formation markers. BMD should be monitored, adequate prophylaxis and treatment established, and glucocorticoid doses optimized to minimize the risk of future fractures.

Improved Insulin Sensitivity during Pioglitazone Treatment Is Associated with Changes in IGF-I and Cortisol Secretion in Type 2 Diabetes and Impaired Glucose Tolerance

Background. Hypercortisolism and type 2 diabetes (T2D) share clinical characteristics. We examined pioglitazone's effects on the GH-IGF-I and HPA axes in men with varying glucose intolerance. Methods. 10 men with T2D and 10 with IGT received pioglitazone 30–45 mg for 12 weeks. OGTT with microdialysis in subcutaneous adipose tissue and 1 μg ACTH-stimulation test were performed before and after. Glucose, insulin, IGF-I, IGFBP1, and interstitial measurements were analyzed during the OGTT. Insulin sensitivity was estimated using HOMA-IR. Results. HOMA-IR improved in both groups. IGF-I was initially lower in T2D subjects (P = 0.004) and increased during treatment (−1.4 ± 0.5 to −0.5 ± 0.4 SD; P = 0.007); no change was seen in IGT (0.4 ± 39 SD before and during treatment). Fasting glycerol decreased in T2D (P = 0.038), indicating reduced lipolysis. Fasting cortisol decreased in T2D (400 ± 30 to 312 ± 25 nmol/L; P = 0.041) but increased in IGT (402 ± 21 to 461 ± 35 nmol/L; P = 0.044). Peak cortisol was lower in T2D during treatment (599 ± 32 to 511 ± 43, versus 643 ± 0.3 to 713 ± 37 nmol/L in IGT; P = 0.007). Conclusions. Pioglitazone improved adipose tissue and liver insulin sensitivity in both groups. This may explain increased IGF-I in T2D. Pioglitazone affected cortisol levels in both groups but differently, suggesting different mechanisms for improving insulin sensitivity between T2D and IGT.

Differences in insulin resistance markers between children born small for gestational age or born preterm appropriate for gestational age

AIM

To evaluate the impact of prenatal or postnatal compromised environment on glucose homoeostasis in children born preterm and appropriate for gestational age or small for gestational age (SGA) at term.

METHOD

Seventy-seven children (median 9.9 years, range 8.5-10) born at Karolinska Hospital were allocated to three groups: 21 subjects born before 30 weeks of gestational age (preterm), 26 SGA at term and 30 at term with appropriate birth weight (control). Anthropometric measurements were taken, and fasting blood samples for haemoglobin A1c, glucose, insulin, IGFBP-1, IGF-1 and lipid profile were taken. Glucose, insulin and IGFBP-1 samples were taken at 0, 30 and 120 min during an oral glucose tolerance test (OGTT).

RESULTS

Subjects born preterm or SGA were shorter and thinner compared with Controls. After adjustment for body mass index (BMI), the SGA group had higher basal insulin levels (p = 0.029), higher homoeostasis model assessment-insulin resistance (p = 0.012) and lower whole-body insulin sensitivity index (p = 0.007) than Controls. IGFBP-1 decrease during OGTT was attenuated in the Preterm group compared with the Control (p = 0.045) and SGA groups (p = 0.007).

CONCLUSION

The higher fasting insulin level in the SGA children, adjusted for BMI, could indicate peripheral insulin resistance. Preterm born children had reduced suppression of IGFBP-1 during OGTT, suggesting hepatic insulin resistance.

Effects on insulin sensitivity and body composition of combination therapy with GH and IGF1 in GH deficient adults with type 2 diabetes

OBJECTIVE

The aim of this trial was to evaluate the effect on insulin sensitivity and body composition of combination therapy with GH and IGF1 in adults with GH deficiency (GHD) and diabetes.

DESIGN, PATIENTS AND METHODS

A 6-month randomised placebo-controlled pilot study. Fourteen adults with GHD and type 2 diabetes were included. All received rhGH (0.15 mg/day for 1 month and 0.3 mg/day for 5 months) and were randomised to rhIGF1 (15 μg/kg per day for 1 month and 30 μg/kg per day for 5 months) or placebo. Insulin sensitivity was evaluated with euglycaemic hyperinsulinaemic clamp and body composition by computed tomography of abdominal and thigh fat, as well as bioimpedance.

RESULTS

Twelve patients completed the study. They were overweight and obese; at baseline, insulin sensitivity (M-value) was low. IGF1 and IGF1 SDS increased in both groups, with the highest increase in the GH and IGF1 group. Positive changes in M-value by +1.4 mg/kg per min, in subcutaneous abdominal fat by -60.5 ml and in fat-free mass by +4.4% were seen in the GH and IGF1 group. Corresponding values in the GH and placebo-treated group were -1.5 mg/kg per min, +23 ml and -0.04% respectively (P=0.02, P=0.04 and P=0.03 for delta values between groups). No safety issues occurred.

CONCLUSIONS

Combined GH and IGF1 treatment resulted in positive, but rather small effects, and might be a treatment option in a few selected patients.

Fibronectin glycation increases IGF-I induced proliferation of human aortic smooth muscle cells

The advanced glycation end products, namely AGEs, contribute to long-termed complications of diabetes mellitus, including macroangiopathy, where smooth muscle cells (SMC) proliferation stimulated by platelet-derived growth factor (PDGF) isoforms and insulin-like growth factor-I (IGF-I) plays an important role. The objective of the present study was to investigate the effect of an AGE-modified extracellular matrix protein on IGF-I induced SMC proliferation and on the IGF-I-IGF binding protein 4 (IGFBP-4) axis under basal conditions and after stimulation with PDGF-BB. IGF-I resulted in significantly higher thymidine incorporation in SMC seeded on AGE-modified fibronectin (AGE-FN) in comparison to cells seeded on fibronectin (FN). This augmented proliferation could not be accounted for by increased expression of IGF-IR, by decreased secretion of IGFBP-4, a binding protein that inhibits IGF-I mitogenic effects or by increased IGF-IR autophosphorylation. PDGF-BB did not modulate IGF-IR and IGFBP-4 mRNA expression in any of the substrata, however, this growth factor elicited opposite effects on the IGFBP-4 content in the conditioned media, increasing it in cells plated on FN and diminishing it in cells plated on AGE-FN. These findings suggest that one mechanism by which AGE-modified proteins is involved in the pathogenesis of diabetes-associated atherosclerosis might be by increasing SMC susceptibility to IGF-I mitogenic effects.

Increased Urine IgM and IgG(2) Levels, Indicating Decreased Glomerular Size Selectivity, Are Not Affected by Dalteparin Therapy in Patients with Type 2 Diabetes

Fifty-four type 2 diabetic patients with neuroischemic foot ulcers were randomised to treatment with 5000 IU of dalteparin, (n = 28), or physiological saline, (n = 26), once daily until ulcer healing or for a maximum of 6 months. Thirty-three patients had normo-, 15 micro-, and 6 macroalbuminuria. The urinary levels of IgM and IgG₂ were elevated in 47 and 50 patients, respectively. Elevated urinary levels of IgM and IgG₂ indicate decreased glomerular size selectivity. Urine IgM levels were associated with IGF-1/IGFBP-1 and IGFBP-1 levels. Dalteparin treatment increased urinary levels of glycosaminoglycans (P < 0.001) and serum IGFBP-1 (P < 0.05) while no significant effects were seen in any of the other studied parameters. In conclusion, dalteparin therapy in patients with type 2 diabetes had no effects on urinary levels of albumin, IgM, or IgG₂ despite significantly increased glycosaminoglycans in urine. Elevated urinary levels of IgM and IgG₂ might be more sensitive markers of renal disease than albuminuria in patients with type 2 diabetes and antihypertensive therapy.

Insulin sensitivity and lipid profile in prolactinoma patients before and after normalization of prolactin by dopamine agonist therapy

Hyperprolactinemia has been associated with impaired metabolism, including insulin resistance. However, the metabolic effects of elevated prolactin (PRL) levels are not completely clarified. The aim of this study was to obtain more insights of metabolic consequences in hyperprolactinemia patients. Fourteen consecutive patients, eight women and six men, aged 39.7 (±13.7) years with prolactinomas (median PRL 72 [49-131] μg/L in women and 1,260 [123-9,600] μg/L in men) were included. Anthropometric data and metabolic values were studied before and after 2 and 6 months on DA agonists (Bromocriptine [5.7 (±3.9) mg/day, n = 13] or Cabergoline [0.5 mg/week, n = 1]). Euglycemic hyperinsulinemic clamps were studied in six patients before and after 6 months of treatment. PRL normalized in all patients. Anthropometric data changed only in males with a significant decrease of median body weight (95.6 [80.7-110.1] to 83.4 [77.8-99.1] kg, P = 0.046), waist circumference and fat percentage after 6 months. LDL cholesterol was positively correlated to PRL at diagnosis (r = 0.62, P = 0.025) and decreased within 2 months (3.4 [±0.9] to 2.9 [±0.6] mmol/L, P = 0.003). Insulin, IGFBP-1 and total adiponectin levels did not change. Insulin sensitivity tended to improve after 6 months; M-value from 5.7 (±1.8) to 7.8 (±2.6) mg/kg/min, P = 0.083 and per cent improvement in M-value was correlated to per cent reduction in PRL levels (r = -0.85, P = 0.034). In conclusion, beneficial metabolic changes were seen in prolactinoma patients after treatment with DA agonists, underscoring the importance of an active treatment approach and to consider the metabolic profile in the clinical management of hyperprolactinemia patients.

The predictive value of inflammatory activity and markers of the adipo-insular axis on restenosis in patients with type 2 diabetes

AIMS

Patients with type 2 diabetes (T2DM) have a high restenosis rate after percutaneous coronary intervention (PCI). This study investigated whether markers of inflammation and the adipo-insular axis associated with T2DM and poor metabolic control were able to predict restenosis after PCI in T2DM patients.

METHODS AND RESULTS

The predictive value of traditional and non-traditional risk markers, including IL-1β, IL-6, TNF-α, hsCRP, interferon gamma, leptin, IGF-I, insulin, proinsulin and NT-proBNP, was investigated in 82 patients with T2DM. A re-angiography 6 months after the index percutaneous coronary intervention (PCI) revealed that 43% of the patients had a restenosis. In a multiple regression analysis, the only independent predictors of restenosis were fasting glucose before the PCI and previous myocardial infarction (odds ratio [OR] 1.44, 95% confidence interval [CI] 1.07-1.92; p = 0.015 and OR 8.00, 95% CI 2.49-25.67; p ≤ 0.001, respectively). None of the other markers remained as significant predictors.

CONCLUSION

Fasting glucose prior to the PCI was an independent predictor of restenosis in patients with T2DM while analyses of a variety of markers related to inflammation and the adipo-insular axis did not add any further information.

Insulin-glucose infusion given before hemodialysis increases IGF-I in type 2 diabetes patients with chronic kidney disease

OBJECTIVE

Hemodialysis is associated with catabolism and one contributing factor could be decreased bioavailable IGF-I. The aim of this investigation was to study the response of IGF-I and IGFBP-1 to a euglycemic hyperinsulinemic clamp before hemodialysis in type 2 diabetes (T2D) with chronic kidney disease on hemodialysis (CKD5D). Stage 5 (Stages 0-5 according to renal function) indicates a GFR less than 15 mL/min/1.73 m², D indicates hemodialysis. The response was compared with that in type 1 diabetes (T1D) with normal renal function.

DESIGN

Five overnight fasted patients with T2D with CKD5D were subjected to an insulin infusion (1.6 mU/kg/h) for 4 h after which they had lunch followed by a four hour hemodialysis session. The results were compared with results from a previous study in seven T1D patients with normal renal function who had received a similar clamp the same insulin dose with the addition of an initial bolus dose. Blood samples were drawn at 15 to 30 min intervals for analysis of IGFBP-1, IGF-I and insulin and at 5 min intervals to determine blood glucose.

RESULTS

There was no significant change between pre- and postdialysis values of IGF-I but there was a significant 29% increase (p<0.05) at the end of hemodialysis compared with the basal levels before insulin infusion in the T2D patients with CKD5D. The fasting mean levels of IGFBP-1 were increased in both T1D with normal renal function (geometric mean: 216 μg/l, range 169-275 μg/l) and in T2D with CKD5D (geometric mean: 112 μg/l , range 78-162 μg/l, p=0.15 compared with T1D patients) in spite of a high mean insulin level (32±5 mU/l). Insulin caused a similar decrease (p<0.05 all groups) in IGFBP-1 mean levels for the first 90 min in the T2D patients with CKD5D (73±7% of basal IGFBP-1 values) and the T1D patients (69±6%) with normal renal function. After 90 min there was a blunted response in the T2D patients with CKD5D whereas IGFBP-1 in the T1D patients with normal renal function continued to decline. After hemodialysis the IGFBP-1 serum levels increased compared with the levels at the end of insulin infusion but the predialysis values remained significantly lower than before the insulin infusion.

CONCLUSION

Type 2 diabetes patients with chronic kidney disease requiring hemodialysis (CKD5D) have a high mean basal level of IGFBP-1 in spite of increased insulin levels. The first 90 min response of IGFBP-1 to insulin infusion is similar in T2D patients with CKD5D and T1D patients with normal renal function. After 90 min of insulin infusion a blunted decrease in IGFBP-1 was seen in T2D patients with CKD5D compared with type \1 diabetes with normal renal function. Insulin infusion before hemodialysis reduced the earlier reported increase in IGFBP-1 and increased IGF-I levels. Insulin infusion before dialysis in patients with CKD5D should be further studied since it could contribute to an anabolic effect with more bioavaialable IGF-I thus reducing the catabolic effect of hemodialysis.

Interactions between oral contraceptive status and GSTM1 and GSTT1 deletions on insulin-like growth factor-1 (IGF-1) plasma levels in young healthy women

OBJECTIVE

Insulin-like growth factor-1 (IGF-1) is essential for the pubertal growth spurt and for normal mammary gland development. IGF-1 increases premenopausal breast cancer risk. Oral contraceptives (OCs) decrease IGF-1 in most women. The endogenous estrogens and their metabolites also influence IGF-1 levels. Glutathione S-transferases (GSTs) are involved in estrogen metabolism. We aimed to study IGF-1 levels and body size in relation to GSTM1 and GSTT1 deletions, and GSTP1*1B and current oral contraceptive (OC) status.

DESIGN

Questionnaires on reproductive factors and OC use were completed and blood samples were obtained during menstrual cycle day 18-23 in healthy women (≤40 years) from breast cancer high-risk families. IGF-1 was analyzed with radioimmunoassay. Genetic analyses were done with PCR based methods. Initially 258 women were included. After exclusion 229 women were finally included in the analyses of IGF-1 in relation to GSTM1 and GSTT1.

RESULTS

Among the 142 non-OC users, GSTM1*0/*0 or GSTT1*0/*0 alone were associated with lower IGF-1 levels while homozygous GSTM1*0/*0/GSTT1*0/*0 carriers had higher IGF-1 levels (P(interaction)=0.024). In the 87 OC users, GSTM1*0/*0 or GSTT1*0/*0 alone were associated with higher IGF-1 levels while homozygous GSTM1*0/*0/GSTT1*0/*0 carriers had lower IGF-1 levels (P(interaction)=0.010). Among all 229 women, a three-way interaction model showed an interaction between the GSTM1*0/*0/GSTT1*0/*0 genotype and OC use on IGF-1 levels (P(interaction)=0.003). GSTP1*1B was not associated with IGF-1. The GSTM1*1/GSTT1*0/*0 genotype was associated with high body weight (P=0.003) and GSTM1*0/*0/GSTT1*0/*0 was associated with early growth (P=0.003).

CONCLUSION

Both OC use and GSTT1 and GSTM1 genotypes may influence IGF-1 levels. Further studies are warranted to confirm our finding and elucidate the clinical importance.

Associations between amino acids and bone mineral density in men with idiopathic osteoporosis

Idiopathic osteoporosis in middle-aged men is characterized by low-level bone formation. Inhibited anabolism may be involved in the pathogenesis of the disease and amino acids may be of importance. In the present study fasting amino acid profiles in plasma and erythrocytes were determined in 22 male idiopathic osteoporosis (MIO) patients and in 20 age-matched healthy men and associated with bone mineral density, bone histomorphometry and hormones. The osteoporotic patients had normal plasma essential amino acids but increased non-essential amino acids (p=0.001), particularly glutamine and glycine. The ratio essential/non-essential amino acids, an index of protein nutritional status, was decreased in the MIO patients (0.59 (0.04) μmol/l, mean (SD)), compared to controls (0.66 (0.05), p=0.001). In the MIO patients, the ratio essential/non-essential plasma amino acids (r=0.60, p=0.003) was positively correlated with lumbar spine bone mineral density. The erythrocyte amino acids represent a large proportion of the free amino acids in blood. A novel finding was the lower levels of erythrocyte tryptophan in MIO (12 (2) μmol/l) compared to controls (16 (3), p=0.001) and decreased erythrocyte/plasma ratio (0.28 (0.07) vs. 0.33, (0.06), p<0.01), suggesting an altered amino acid transport of tryptophan between plasma and erythrocytes. In the combined group of MIO and control men (n=42), bone mineral density was positively correlated with erythrocyte tryptophan in both the lumbar spine (r=0.45, p=0.003) and femoral neck (r=0.56, p<0.001). The bone histomorphometric variables wall thickness, trabecular thickness and mineral apposition rate were all positively associated with erythrocyte tryptophan levels in the MIO patients. In the combined group of MIO and controls, a multiple regression analysis showed that erythrocyte tryptophan could explain 22% of the variation of lumbar spine and 30% of the variation in femoral neck bone mineral density. We conclude that men with idiopathic osteoporosis have changes in free amino acid profiles which indicate their altered utilization. The correlations between tryptophan and bone mineral density and bone histomorphometry suggest a link between tryptophan and osteoblast function which may be important for bone health.

Infliximab therapy increases body fat mass in early rheumatoid arthritis independently of changes in disease activity and levels of leptin and adiponectin: a randomised study over 21 months

Introduction

Rheumatoid arthritis (RA) is associated with changes in body composition and bone mineral density (BMD). The purpose of the present study was to evaluate whether anti-TNF treatment in early RA has an impact on body composition and BMD besides that which could be achieved by intensive disease-modifying anti-rheumatic drug (DMARD) combination therapy.

Methods

Forty patients with early RA who failed treatment with methotrexate up to 20 mg/week for 3 months were randomised to addition of sulphasalazine and hydroxychloroquine (treatment A) or addition of infliximab (treatment B). At 3, 12 and 24 months, body composition and BMD were assessed by total-body dual-energy X-ray absorptiometry. At the same time points, leptin, adiponectin, apolipoproteins, insulin-like growth factor-1 (IGF-1) and markers of bone remodelling were analysed. Compliance to treatment was considered in the analyses. Data were analysed with a mixed, linear model.

Results

Patients treated with anti-TNF had a significant increase in fat mass at 2 years, 3.8 (1.6 to 5.9) kg, in contrast to patients in treatment A, 0.4 (-1.5 to 2.2) kg (P = 0.040), despite similar reduction in disease activity. Both treatment strategies prevented loss of muscle mass and bone. Leptin concentrations increased significantly in both groups at 2 years and adiponectin increased significantly at 2 years in treatment A and at 1 year in treatment B. There were no significant changes in apolipoproteins or IGF-1. The markers of bone resorption decreased at 12 months in both treatment groups with no significant difference between the treatment groups.

Conclusions

Infliximab therapy increased body fat mass, an effect that was not achieved with the combination of DMARDs, despite a similar reduction in disease activity, and thus seemed to be drug specific. The increase of fat mass was not associated with an exacerbated atherogenic lipid profile. Leptin and adiponectin concentrations increased in both treatment groups. The increase of adiponectin may partially explain the reduced frequency of cardiovascular diseases found when disease activity is reduced in RA.

Trial registration

ISRCTN39045408.

IGF-binding protein 1 and abdominal obesity in the development of type 2 diabetes in women

OBJECTIVE

Low levels of IGF-binding protein 1 (IGFBP1) are associated with metabolic syndrome and predict diabetes development in men. The aim of this study was to determine the levels of IGFBP1 in women who later develop diabetes, in relation to abdominal obesity, and to compare these levels with those of men.

METHODS

IGFBP1 levels were determined at baseline and after 8 years in a case-control, prospective study of Swedish women aged 35-56 years. Individuals with normal oral glucose tolerance test (OGTT) who developed abnormal glucose regulation (n=240) were pair matched to controls for age and family history of diabetes and also compared to men of the same age (n=355).

RESULTS

Low fasting IGFBP1 and increased waist measurement predicted development of diabetes in women (n=60; odds ratio (OR) 70, 95% confidence interval (CI) 8-661, lowest tertile and OR 27, 95% CI 5-141, highest tertile). In women developing diabetes, baseline IGFBP1 levels were lower than expected for fasting insulin values, were associated with impaired suppression after OGTT and increased during 8 years despite an increase in fasting insulin. All individuals in the highest tertile for waist and with <or=40% suppression of IGFBP1 developed diabetes within 8 years. Circulating IGFBP1 concentrations were higher in women compared to men. Women and men who developed diabetes had a similar degree of abdominal obesity, corrected for height.

CONCLUSIONS

We conclude that low IGFBP1 and elevated waist measurement predict diabetes development and that IGFBP1 production is suppressed by a novel factor(s) in women developing diabetes. Increasing levels of IGFBP1 during the emergence of diabetes in men and women suggest the emergence of hepatic insulin resistance.