Free Insulin-like Growth Factor-1 Levels Research Articles

Association Between Serum Insulin-Like Growth Factor 1 Levels and the Clinical Symptoms of Chronic Schizophrenia: Preliminary Findings.

Purpose: Insulin-like growth factor 1 (IGF-1) is a trophic mediator that is regulated by growth hormone and associated with the proliferation, development, and growth of neural cells. IGF-1 may be associated with the pathophysiology of schizophrenia, but this association remains controversial. This study aimed to investigate the relationship between serum IGF-1 levels and psychiatric symptoms in patients with chronic schizophrenia.Patients and Methods: A total of 65 patients were recruited from the University of Occupational and Environmental Health, Komine Eto Hospital, Moji Matsugae Hospital, Shin-Moji Hospital, and Tsutsumi Hospital in Kitakyushu between September 2019 and June 2020. Further, 20 healthy age- and sex-matched control participants were recruited from the Komine Eto Hospital and the University of Occupational and Environmental Health. Patients with schizophrenia were assessed using the Positive and Negative Syndrome Scale (PANSS) and the Drug-Induced Extrapyramidal Symptoms Scale. Serum levels of free plus albumin-bound IGF-1 (IGF-1) were measured by immunoradiometric assay. The measurements were performed using antibody beads for bound/free separation. Associations between serum IGF-1 levels and the PANSS scores were determined. We also examined the associations between serum IGF-1 levels and diabetes, antipsychotic drug use, and disease duration.Results: No significant difference was found in the serum IGF-1 level between patients with schizophrenia and healthy controls. Serum IGF-1 levels were significantly negatively correlated with the PANSS total score (R2 = 0.06, p = 0.015) and PANSS general score (R2 = 0.088, p = 0.008), but not with the PANSS positive scores and PANSS negative scores. Serum IGF-1 levels were not related to the prevalence of diabetes (p = 0.64). However, a significant correlation was observed between serum IGF-1 levels and age (B = −1.88, p < 0.0001). Serum IGF-1 levels could not distinguish patients with schizophrenia and healthy controls.Conclusion: The association between serum IGF-1 levels and psychiatric symptoms may be complicated in patients with chronic schizophrenia.

Insulin-Like Growth Factor 1 Related to Chronic Low-Grade Inflammation in Patients with Obesity and Early Change of its Levels After Laparoscopic Sleeve Gastrectomy.

Insulin-like growth factor 1 (IGF1) and insulin-like growth factor binding protein (IGFBP) have an influence on metabolism. However, changes in metabolism after sleeve gastrectomy (SG) are not clearly known. This study investigated the change in IGFBP3 levels in obesity after bariatric surgery. We evaluated 36 patients with obesity (14 males, aged 31.36 ± 7.06years and 22 females, aged 32.55 ± 11.40years) at baseline and 3months after SG. Changes in their IGF1, IGFBP3, and IGF1/IGFBP3 ratios and glucose-lipid metabolic, inflammation, and oxidative stress parameters were measured. Enzyme-linked immunosorbent assay was used to measure their IGF1 and IGFBP3 levels. (1) IGFBP3 levels were negatively associated with waist circumference (WC) and waist-to-hip ratio (r = - 0.482, P = 0.043; r = - 0.503, P = 0.033); total IGF1 levels were negatively associated with body mass index and WC (r = - 0.569, P = 0.014; r = - 0.470, P = 0.048); and free IGF1 levels were negatively related to tumor necrosis factor (TNF)-α level independent of age (r = - 0.544, P = 0.020). Free IGF1 levels were negatively associated with uric acid, interleukin-6 (IL-6), IL-8, and TNF-α levels (r = - 0.646, P = 0.032; r = - 0.667, P = 0.025; r = - 0.641, P = 0.033; r = - 0.733, P = 0.010) and positively associated with superoxide dismutase activity (r = 0.635, P = 0.036) in females; this relation was not significant in males (all P > 0.05). Total IGF1 was also negatively associated with C-reactive protein (CRP) level in females (r = - 0.671, P = 0.024). (2) IGFBP3 level significantly decreased at 3months after bariatric surgery in females (P < 0.001) but not in males (P = 0.815). Total IGF1 level significantly decreased after bariatric surgery (P = 0.048); the change was also significant in females (P = 0.014) but not in males (P = 0.626). Free IGF1 level after bariatric surgery was not statistically different between males (P = 0.605) and females (P = 0.628). (3) In females, the change in IGFBP3 level was associated with a change in high-density lipoprotein cholesterol and free fatty acid levels (r = 0.607, P = 0.003; r = 0.546, P =0.016), and a change in total IGF1 level was associated with a change in CRP level (r = 0.664, P = 0.009). IGF1 level was related to chronic low-grade inflammation and oxidative stress in obesity, especially in females. IGFBP3 and IGF1 levels decreased in obesity after SG, especially in females. Changes in IGF/IGFBP3 levels were associated with a change in the inflammatory state after surgery.

Moderate intensity exercise in hypoxia increases IGF-1 bioavailability and serum irisin in individuals with type 1 diabetes.

Aim:This study aimed to determine the effect of moderate intensity continuous exercise (Ex) and hypoxia (Hyp) on serum brain-derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1) and its binding protein-3 (IGFBP-3), irisin and cytokines levels in patients with type 1 diabetes (T1D).Methods:A total of 14 individuals with T1D (age: 28.7 ± 7.3 years) and 14 healthy adults (age: 27.1 ± 3.9 years) performed 40-min continuous Ex at moderate intensity (50% lactate threshold) on a cycle ergometer in normoxia (Nor) and Hyp (FiO2 = 15.1%) Biochemical factors, glucose concentrations and physiological variables were measured at rest, immediately and up to 24 h after both Ex protocols.Results:Patients with T1D had significantly lower pre-Ex serum concentrations of BDNF (p < 0.05, p < 0.01), and total IGF-1 (p < 0.001, p < 0.05) and significantly higher irisin levels (p < 0.05, p < 0.01) in Nor and Hyp, compared with healthy subjects. Ex significantly increased in T1D group serum BDNF (in Nor only p < 0.05) and total IGF-1 levels in Nor and Hyp (p < 0.001 and p < 0.01, respectively). Immediately after Ex in Hyp, freeIGF-1 (p < 0.05) and irisin levels (p < 0.001) were significantly higher compared with the levels induced by Ex alone. Free IGF-1 and irisin serum levels remained elevated in 24 h post-Ex in Hyp. In T1D, significant blood glucose (BG) decrease was observed immediately after Ex in Hyp (p < 0.001) and in 24 h recovery (p < 0.001) compared with pre-Ex level.Conclusion:The study results suggest that moderate intensity continuous Ex has beneficial effect on BDNF and IGF-1 levels. Ex in hypoxic conditions may be more effective in increasing availability of IGF-1. The alterations in the post-Ex irisin levels and IGF-1 system may be contributing to more effective glycaemia control in patients with T1D.

Effects of IGF-1 on the Cardiovascular System.

Cardiovascular (CV) diseases are the most common health problems worldwide, with a permanent increase in incidence. Growing evidence underlines that insulin-like growth factor 1 (IGF-1) is a very important hormone responsible for normal CV system physiology. IGF-1 is an anabolic growth hormone, responsible for cell growth, differentiation, proliferation, and survival. Despite systemic effects, IGF-1 exerts a wide array of influences in the CV system affecting metabolic homeostasis, vasorelaxation, cardiac contractility and hypertrophy, autophagy, apoptosis, and antioxidative processes. The vasodilatory effect of IGF-1, is achieved through the regulation of the activity of endothelial nitric oxide synthase (eNOS) and, at least partly, through enhancing inducible NOS (iNOS) activity. Also, IGF-1 stimulates vascular relaxation through regulation of sodium/potassiumadenosine- triphosphatase. Numerous animal studies provided evidence of diverse influences of IGF-1 in the CV system such as vasorelaxation, anti-apoptotic and prosurvival effects. Human studies indicate that low serum levels of free or total IGF-1 contribute to an increased risk of CV and cerebrovascular disease. Large human trials aiming at finding clinical efficacy and outcome of IGF-1-related therapy are of great interest. We look forward to the development of new IGF 1 therapies with minor side effects. In this review, we discuss the latest literature data regarding the function of IGF-1 in the CV system in the physiological and pathophysiological conditions.

Clinical Characteristics and Postoperative Recovery of Hypopituitarism in Patients with Nonfunctional Pituitary Adenoma

To investigate the clinical characteristics of hypopituitarism and its reversibility after surgery for nonfunctional pituitary adenoma (NFPA); analyze the correlation between tumor size and hypopituitarism incidence; and predict hypopituitarism by tumor volume and maximum diameter. We retrospectively reviewed 164 patients with NFPA who underwent surgical treatment at Peking Union Medical College Hospital from January 2016 to December 2016. Demographic, imaging, and endocrine data were collected during preoperative, postoperative, and long-term follow-up (21.1 ± 3.3 months) periods. Differences in hormone levels were analyzed by paired and independent samples t-tests. The cut-off values of tumor size and volume to predict hypopituitarism were calculated by receiver operating characteristic curves. In total, 80.4% (132/164) of patients had anterior pituitary hypofunction and 48.4% patients had hypogonadism; the recovery rate of luteinizing hormone was 80.9%, and follicular-stimulating hormone was 60%. In total, 36.5% of patients had hypothyroidism; the recovery rate of thyroxine was 85%, free thyroxine was 87.8%, and thyroid-stimulating hormone was 100.0%. Finally, 27.4% of patients had insulin-like growth factor 1 (IGF-1)/growth hormone (GH) hypofunction, and the recovery rate of IGF-1 was 77.8%. The preoperative free thyroxine, thyroxine, GH, IGF-1, follicular-stimulating hormone, and luteinizing hormone levels were significantly lower in the giant adenoma group (n= 43) than in the large adenoma group (n= 121). The hypopituitarism predictive cut-off value of tumorvolume was 3105.1 mm3 and that of tumor diameter was 23.5 mm. NFPA has a significant influence on gonadal hormone, IGF-1/GH, and thyroid hormone. NFPA can cause single- or multiple-hormone reduction in each pituitary target gland. Tumor size is positively correlated with the incidence and degree of hypopituitarism. NFPA-induced hypopituitarism is significantly recovered after surgical treatment.

Insulin-like growth factor-1 (IGF1) in systemic lupus erythematosus: relation to disease activity, organ damage and immunological findings.

Background Insulin growth factor-1 (IGF1) activates cell proliferation pathways and inhibits apoptosis. IGF1 is involved in tumour growth and required for T-cell independent activation of B cells. Activated B cells and autoantibody production are a hallmark of systemic lupus erythematosus (SLE). To investigate the possible role of IGF1 in SLE, we studied IGF1 across clinical characteristics, immunological biomarkers, disease activity and organ damage in SLE patients. Method In a cross-sectional study, we collected clinical characteristics, medication, disease activity (SLEDAI-2K) and organ damage (SDI) for 94 SLE patients. Autoantibodies and cytokines were measured by ELISA, and levels of IGF1 and IGF binding protein 3 (IGFBP3) by chemiluminescence. Free IGF1 was estimated by the IGF1:IGFBP3 ratio. Healthy controls served as a comparator group. Results There was a significant age-related decline in IGF1, IGFBP3 and free IGF1 (IGF1:IGFBP3 ratio) that was similar in SLE patients and controls with very few outliers. Free IGF1 was inversely related to blood pressure (Rs -0.327, p < 0.01) and HbA1c (Rs -0.31, p < 0.01). Free IGF1 was higher in disease-modifying antirheumatic drug-treated patients ( p < 0.01), but there was no significant association between the IGF1 axis and autoantibody profiles, cytokine levels or SLEDAI-2K or SDI categories. IGF1 correlated inversely with BAFF level and B, natural killer and CD8 + cell counts. Conclusion Free IGF1 levels in SLE patients declined appropriately with age. IGF1 levels were not associated with disease activity, severity or autoantibody levels in SLE. Free IGF1 had positive metabolic effects in SLE and may play an indirect role in dampening the cellular immune response by downregulating B- and T-cell activity.

Combined extracts of Garcinia mangostana fruit rind and Cinnamomum tamala leaf supplementation enhances muscle strength and endurance in resistance trained males

BackgroundA proprietary composition GMCT contains extracts of two popular Asian herbs viz., Garcinia mangostana (GM) fruit rind and Cinnamomum tamala (CT) leaf. We systematically evaluated physical performance and muscle strength enhancing ability of GMCT in a preclinical mouse model followed by a 42-days double-blind placebo controlled human trial in resistance trained adult males.MethodsFour groups of Swiss albino mice (20–30 g body weight) (n = 6) were fed a standard laboratory diet and given Carboxymethylcellulose sodium (CMC), 150 mg/kg GMCT (GMCT-150), 300 mg/kg GMCT (GMCT-300) or 50 mg/kg Oxymetholone (OXY) via oral gavage for 21 days. On day 22, the animals’ physical performance and muscle strength were assessed in a forced swimming test (FST) and forelimb grip strength experiment, respectively.In the human trial, thirty-eight resistance-trained young adults (mean age 26.32 ± 4.39 years, body weight 67.79 ± 12.84 kg, BMI 22.92 ± 3.54 kg/m2) completed the trial. The participants received either GMCT (n = 19; 800 mg daily) or matched placebo (n = 19) for 42 days. As primary variables, 1-RM bench press, 1-RM leg press, and leg extension repetitions were measured at baseline and on days 14, 28 and 42 of the intervention. Anthropometric parameters and serum markers such as free testosterone, insulin-like growth factor 1 (IGF-1), insulin and lactate were also measured before and after the intervention.ResultsGMCT-300 mice showed significant improvement in swimming time (GMCT: 395.3 ± 81.70 s vs. CMC: 271.6 ± 56.86 s; p = 0.0166), distance (GMCT: 341.22 ± 65.88 m vs. CMC: 260.84 ± 49.15 m; p = 0.0461) and grip strength (GMCT: 43.92 ± 6.97 N vs. CMC: 35.0 ± 6.92 N; p = 0.0490), compared with the CMC group.At the end of the 42-day human trial, the per protocol analyses reveal that mean changes from baseline 1-RM bench press (GMCT: 23.47 ± 10.07 kg vs. PL: 3.42 ± 2.06 kg; p < 0.0001), leg press (GMCT: 29.32 ± 16.17 kg vs. PL: 5.21 ± 1.72 kg; p < 0.0001), number of leg extension repetitions (GMCT: 6.58 ± 2.57 vs. PL: 2.05 ± 1.22; p < 0.0001) in GMCT group were significantly improved, compared with placebo. Intergroup difference analyses show that the changes from baseline left arm (GMCT: 1.09 ± 0.36 cm vs. PL: 0.68 ± 0.42 cm; p = 0.0023), right arm (GMCT: 1.50 ± 0.44 cm vs. PL: 1.11 ± 0.43 cm; p = 0.0088) circumference and lean mass (GMCT: 2.29 ± 2.09 kg vs. PL: 0.52 ± 2.58 kg; p = 0.0404) in GMCT group were also significantly improved, compared with placebo. In comparison to placebo, GMCT supplementation did not improve free testosterone, IGF-1, insulin or lactate levels. Parameters of clinical biochemistry, hematology, urine and vital signs of the participants were within the normal range.ConclusionGMCT supplementation is effective in increasing muscle strength, muscle size and, total lean mass, as well as endurance performance.Trial Registration.Clinical Trial Registry of India (CTRI/2015/01/005374), Registered on Jan 07, 2015; CTRI Website URL - http://ctri.nic.in

Glucogenic treatment creates an optimal metabolic milieu for the conception period in ewes

This study determined the influence of a short-term glucogenic nutritional treatment on circulating concentrations of glucose, insulin, insulin-like growth factor 1 (IGF-1), nonesterified fatty acids (NEFA), and urea, and on their correspondent levels in follicular fluid (FF) collected 12 h after the end of the treatment. After estrous synchronization with intravaginal progestagen-impregnated sponges, 20 Sarda ewes were randomly allocated into two experimental groups (GLU and WAT) and, from day 7 to day 10 (day 0 = day of sponge removal), the GLU group was gavaged with a glycogenic mixture, whereas the WAT group was gavaged with water (control group). Follicular development was stimulated by FSH administration from day 8 to 10. At day 11, ovaries were collected and follicular fluid processed. Plasma changes were assessed from day 6 to 11. In GLU group, circulating concentration of glucose (P < 0.0001), insulin (P < 0.0001), and IGF-1 (P < 0.01) rose significantly, whereas NEFA and urea concentrations decreased (P < 0.0001), as compared with controls. In particular, in FF the higher glucose concentrations found in GLU ewes compared with controls (P < 0.0001) were not accompanied by any increase in insulin and IGF-1 concentrations. NEFA (P < 0.0001) and urea (P < 0.0001) were lower in FF of GLU than WAT group, although NEFA clearance in the ovary proved to be less efficient than at the systemic level. No significant difference between groups was found in FF concentrations of pregnancy-associated plasma protein A (a protease regulating the levels of free IGF-1 in follicles), glutathione, and in its total antioxidant capacity. These results suggest that glycogenic mixture administration creates a suitable follicular microenvironment for the conception period in dairy ewes.

The Effect of Supplementing Sodium Butyrate Containing Feed with Glutamine and/or Glucose on the Structure of the Piglet Digestive Tract and Selected Blood Indices

Abstract The effect of supplementing the standard piglet diet containing sodium butyrate with glutamine and/or glucose on the structure of the piglet digestive tract and the small intestine epithelium, acidity and volatile fatty acid content of its digesta was investigated. The free amino acids level, insulin and insulin-like growth factor-1 (IGF-1) concentration in the blood were also analysed. The experiment was performed on 156 piglets (15 litters) allocated to 5 experimental groups, 3 litters in each. Group I (C, negative control) received a basal mixture with no supplement. Group II (SB, positive control) was fed the same basal diet containing additionally 3 g of sodium butyrate per kg. Group III and IV, besides sodium butyrate, received additionally 10 g of glutamine (GT) or glucose (GC), respectively. The last group V received all these supplements, i.e. SB+GT+GC (3, 10, 10 g per kg, respectively). At 60 days of age, the piglets (6 animals from each group) were slaughtered and their intestines were measured and weighed. The piglets in group SB+GT+GC receiving all the supplements grew slightly faster than the others, and at the end of the experiment the differences in body weight were significant. The total intestinal mass of the piglets fed with glucose or all the supplements was significantly higher than that of the piglets receiving glutamine but there was no significant difference in the total length of intestines. There was also no significant difference in acidity of chyme along the entire length of the gastrointestinal tract. Digesta in the jejunum of both control groups (C, SB) contained significantly more SCFA than the remaining groups. In the caecum their content in the negative control and the group fed with all supplements was significantly higher when compared to the butyrate and glucose group. In the duodenum villus height was similar in all the groups but in the jejunum it was significantly higher in the group receiving all supplements than in other groups. Free amino acids level was lowest in the piglets receiving glucose but there was no difference between the remaining groups. The lowest level of IGF-1 was found in the same group and this difference was significant when compared with remaining groups, except C. It is concluded that glutamine and glucose, when given together with sodium butyrate, improve the structure of piglet jejunum epithelium and average body weight gains. A supplement of glucose significantly lowers free amino acid content and IGF-1 level in piglet blood.

Effects of acute exercise on salivary free insulin-like growth factor 1 and interleukin 10 in sportsmen.

Saliva analysis is rapidly developing as a tool for the assessment of biomarkers of sports training. It remains poorly understood whether a short bout of sport training can alter some salivary immune biomarkers. To investigate the effect of acute exercise using football training session on salivary flow rate, salivary free Insulin-like Growth Factor-1 (IGF-1) and Interleukin 10 (IL-10). Saliva samples were collected before and immediately after a football session. Salivary flow rates, salivary levels of free IGF-1 and IL-10 (using ELISA) were determined. Data was analyzed and compared using Related Samples Wilcoxon Signed Rank test (non-parametric test). Relationships between salivary flow rate and levels of free IGF-1 and IL-10 were determined using Spearman correlation test. There were 22 male footballers with a mean age of 20.46 years. Salivary flow rate reduced significantly (p = 0.01) after the training session while salivary levels of free IGF-1 and IL-10 did not show any significant change. Also, there were no correlations between salivary flow rates and salivary levels of free IGF-1 and IL-10 before and after exercise. These findings suggest that acute exercise caused significant reduction in salivary flow rate but no change in the levels of salivary free IGF-1 and IL-10.

Relationship Between Aerobic Fitness, the Serum IGF-1 Profiles of Healthy Young Adult African American Males, and Growth of Prostate Cancer Cells.

The growth of prostate tumors is mediated by the bioavailability of androgens and insulin-like growth factors. This study tested the hypothesis that healthy young adult African American men exhibiting low aerobic capacity (fitness) have serum insulin-like growth Factor-1 (IGF-1) and testosterone levels that promote growth of prostate cancer cells. A cross-sectional data research design was used to study groups of 18- to 26-year-old healthy men exhibiting low and moderate aerobic fitness, based on their peak oxygen consumption (VO2peak). The individual serum levels of IGF-1, IGF-1 binding protein-3 (IGFBP-3), and testosterone were measured. In vitro growth of androgen-dependent LNCaP prostate tumor cells was measured after incubation in culture medium fortified with each subject's serum. Aerobic capacity was significantly greater in the moderate-fitness group than in the low-fitness group without an intergroup difference in body mass index. The serum IGF-1 concentration was significantly higher in the low-fitness group in the absence of an intergroup difference in serum testosterone. The serum IGFBP-3 concentration was significantly lower in the low-fitness group. Prostate tumor cell growth was significantly greater in the cultures incubated in media containing the sera of the low-fitness group than in the sera of the moderate-fitness group. These findings suggest that moderate aerobic fitness in young adults may decrease the circulating levels of free IGF-1 and lower the potential to support growth of prostate cancer cells.

Abstract 2505: Exposure to a therapeutically relevant dose of ionizing radiation reveals colorectal cancer biomarker and associated receptor alterations

Abstract Purpose: Diagnostic and therapeutic radiation exposure to humans is inevitable, and radiation exposure is known to enhance risks of colorectal cancer (CRC) and inflammatory bowel diseases. Radiation exposure has also been observed to promote obesity in humans as well as in rodents. While altered levels of insulin like growth factor 1 (IGF1), leptin, and adiponectin have been reported as potential markers of obesity-related CRC risk, there is a paucity of long-term radiation-risk-markers for intestinal pathologies. The goal of the current study was to evaluate in mice whether obesity-related CRC risk markers have the potential to serve as radiation-associated CRC risk markers after exposure to a clinically relevant γ radiation dose. Methods and materials: Mice (C57BL/6J, 6-8 week old, female; n= 8 per group) were exposed to a γ radiation dose of 2 Gy, commonly used in fractionated radiotherapy. Serum and intestinal tissues were collected two and twelve months after radiation. Serum levels of IGF-1, IGF binding protein 3 (IGFBP3), leptin, and adiponectin were analyzed by enzyme-linked immunosorbent assay (ELISA). Immunohistochemistry was performed on small intestine and colon sections for IGF1 receptor (IGF1R), obesity receptor (OB-R), adiponectin receptor 1 (AdipoR1), adiponectin receptor 2 (AdipoR2) and proliferative marker Ki-67. Results: The levels of free IGF1 and free leptin measured by calculating IGF1/IGFBP3 and leptin/adiponectin ratio showed a distinct pattern. While significantly higher free IGF1 was observed twelve months post-radiation, higher free leptin was observed two months after radiation exposure. Immunohistochemical analysis demonstrated increased IGF1R and OB-R, decreased AdipoR1 and R2, and increased Ki67 in intestinal as well as in colonic sections at both the time points. Conclusions: Considering that one fraction of 2 Gy showed significant alterations in risk markers, we believe exposure to a higher total dose using more fractions will show more pronounced effects. Taken together, this study demonstrates that adipogenic risk markers of CRC could be effective tools to assess CRC risks after therapeutic γ radiation exposures. Note: This abstract was not presented at the meeting. Citation Format: Shubhankar Suman, Albert J. Fornace, Kamal Datta. Exposure to a therapeutically relevant dose of ionizing radiation reveals colorectal cancer biomarker and associated receptor alterations. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2505. doi:10.1158/1538-7445.AM2014-2505

Essential Amino Acid Enriched High-Protein Enteral Nutrition Modulates Insulin-Like Growth Factor-1 System Function in a Rat Model of Trauma-Hemorrhagic Shock

BackgroundNutrition support for critically ill patients supplemented with additional modular protein may promote skeletal muscle protein anabolism in addition to counteracting acute nitrogen loss. The present study was designed to investigate whether the essential amino acid (EAA) enriched high-protein enteral nutrition (EN) modulates the insulin-like growth factor-1 (IGF-1) system and activates the mammalian target of rapamycin (mTOR) anabolic signaling pathway in a trauma-hemorrhagic shock (T-HS) rat model.Methodology/Principal FindingsMale Sprague-Dawley rats (n = 90, 278.18±0.94 g) were randomly assigned to 5 groups: (1) normal control, (2) pair-fed, (3) T-HS, (4) T-HS and standard EN, and (5) T-HS and EAA enriched high-protein EN. Six animals from each group were harvested on days 2, 4, and 6 for serum, gastrocnemius, soleus, and extensor digitorum longus sample collection. T-HS significantly reduced muscle mass. Nutrition support maintained muscle mass, especially the EAA enriched high-protein EN. Meanwhile, a pronounced derangement in IGF-1-IGFBPs axis as well as impaired mTOR transduction was observed in the T-HS group. Compared with animals receiving standard EN, those receiving EAA enriched high-protein EN presented 18% higher serum free IGF-1 levels following 3 days of nutrition support and 22% higher after 5 days. These changes were consistent with the concomitant elevation in serum insulin and reduction in corticosterone levels. In addition, phosphorylations of downstream anabolic signaling effectors - including protein kinase B, mTOR, and ribosomal protein S6 kinase1 - increased significantly in rats receiving EAA enriched high-protein EN.Conclusion/SignificanceOur findings firstly demonstrate the beneficial effect of EAA enriched high-protein EN on the metabolic modulation of skeletal muscle protein anabolism by regulating the IGF-1 system and downstream anabolic signaling transduction.

Changes in pain and insulin-like growth factor 1 in fibromyalgia during exercise: the involvement of cerebrospinal inflammatory factors and neuropeptides

IntroductionFibromyalgia (FM) is characterized by chronic pain. Impaired growth hormone responses and reduced serum insulin-like growth factor 1 (IGF-1) are common in FM. The aim was to examine changes in serum IGF-1, cerebrospinal fluid (CSF), neuropeptides, and cytokines during aerobic exercise in FM patients.MethodsIn total, 49 patients (median age, 52 years) with FM were included in the study. They were randomized to either the moderate- to high-intensity Nordic Walking (NW) program (n = 26) or the supervised low-intensity walking (LIW) program (n = 23). Patients participated in blood tests before and after 15 weeks of aerobic exercise. Changes in serum levels of free IGF-1, pain rating on a 0- to 100-mm scale, pain threshold, and 6-minute walk test (6MWT) were examined. CSF, neuropeptides, matrix metalloproteinase 3 (MMP-3), and inflammatory cytokines were determined. Nonparametric tests were used for group comparisons and correlation analyses.ResultsSerum free IGF-1 levels did not change during 15 weeks of exercise between the two groups, although the 6MWT significantly improved in the NW group (p = 0.033) when compared with LIW. Pain did not significantly change in any of the groups, but tended to decrease (p = 0.052) over time in the total group. A tendency toward a correlation was noted between baseline IGF-1 and a decrease of pain in response to exercise (r = 0.278; p = 0.059). When adjusted for age, this tendency disappeared. The change in serum free IGF-1 correlated positively with an alteration in CSF substance P (SP) levels (rs = 0.495; p = 0.072), neuropeptide Y (NPY) (rs = 0.802; p = 0.001), and pain threshold (rs = 0.276; p = 0.058). Differing CSF SP levels correlated positively to a change in pain threshold (rs = 0.600; p = 0.023), whereas the shift in CSF MMP-3 inversely correlated with an altered pain threshold (rs = -0.569; p = 0.034).ConclusionsThe baseline level of serum free IGF-1 did not change during high or low intensity of aerobic exercise. Changes in IGF-1 correlated positively with a variation in CSF SP, NPY, and pain threshold. These data indicate a beneficial role of IGF-1 during exercise in FM.Trial registration: ClinicalTrials.gov NCT00643006.

Locally produced insulin-like growth factor-1 by orbital fibroblasts as implicative pathogenic factor rather than systemically circulated IGF-1 for patients with thyroid-associated ophthalmopathy

To determine the correlation between clinical activity scores (CAS) of thyroid-associated ophthalmology (TAO) patients and their locally produced and/or systemically circulating insulin-like growth factor-1 (IGF-1), and to assess the possible pathogenic role of IGF-1 in TAO. Eighteen patients with TAO, and 16 age- and gender-matched controls were included in the present study. Among them, orbital tissue surgically collected from five TAO patients and five healthy controls was used for orbital fibroblasts (OFs) culture and in vitro study. Total and free IGF-1 in serum levels were determined by an ELISA kit for all the participants in this study. The IGF-1 concentration in culture media of OFs was determined using a noncompetitive time-resolved radioimmunoassay kit. The effect of octreotide (OCT), a somatostatin analog, on proliferation of OFs was assessed using the MTT assay. IGF-1 mRNA levels were measured by real-time polymerase chain reaction (PCR). Cultured OFs from both TAO patients and normal donors secreted IGF-1, and the secretion continued over a 72 hour period in vitro. IGF-1 secretion by OFs was elevated in the TAO group. Both the elevated secretion of IGF-1 and proliferation of OFs from TAO patients could be inhibited by OCT. Result of quantitative PCR showed that IGF-1 mRNA expression by OFs in TAO patients was up-regulated more than 2-fold compared with normal controls (P < 0.05), and this up-regulation was prevented by OCT treatment. Total and free serum IGF-1 levels in TAO patients were similar to those of normal controls. However, the IGF-1 level in cultured medium of OFs from TAO patients, but not serum levels of IGF-1, was positively correlated with CAS (r = 0.97, P = 0.017). Local production of IGF-1 by cultured OFs may be positively correlated with CAS, whereas systemically circulating IGF-1 may remain unchanged in TAO patients. Thus, locally produced IGF-1 may develop a role in the pathogenesis of TAO in an autocrine or paracrine fashion. The inhibitory effect of OCT on proliferating and IGF-1 mRNA levels of cultured OFs from TAO patients may be used as the mechanistic explanation for somatostatin analog as a valuable option in the treatment of TAO.

Abstract PR-1: Genetic African ancestry and race differences in blood insulin-like growth factor 1 (IGF-1), IGF-2, and IGF binding protein 3 (IGFBP-3)

Abstract Purpose: We have previously reported that African American women have significantly higher IGF-1 levels, and lower IGF-2 and IGFBP-3, compared to white women. This investigation aims to determine if genetic African ancestry is associated with these racial differences in blood IGF levels. Methods: The Southern Community Cohort Study (SCCS) is a prospective cohort study of 86,000 men and women, with two-thirds African American recruitment, designed to investigate racial disparities in cancer. We randomly selected 1000 African American and 1000 non-Hispanic white female participants to support focused investigations of racial differences in biomarkers possibly related to breast cancer. Serum IGF-1, IGF-2, and IGFBP-3 levels were measured by ELISA. We estimated African and European admixture using a panel of 276 ancestry informative genetic markers. Final analyses included 821 African American women and 816 white women after excluding women taking hormone replacement therapy or insulin for diabetes. White women had a low African ancestry (median = 0.4%, range=0.1 % to 17.1 %) and thus were considered as a single ancestry category. For African Americans, cutpoints of &amp;lt;85% (n=149), 85%-95% (n=230), and ≥95% (n=442) defined “low,” “medium,” and “high” African ancestry. Using multivariable linear regression, we estimated differences in IGF levels across ancestry categories while adjusting for age, body mass index (BMI), height, menopausal status, and BMI at age 21 years. Results: African American women having 85% African ancestry. For example, IGF-2 levels among white women and African American women with &amp;lt;85%, 85%-95%, and ≥95% African ancestry were 1771.9 ng/ml, 1713.5 ng/ml, 1620.3 ng/ml, and 1620.6 ng/ml, respectively. African American women with &amp;lt; 85% African ancestry had IGF-2 levels that were about 5.8% higher than African American women with 85%-95% (p=0.03) or ≥95% (p=0.01) ancestry. IGF-1 levels among white women and African American women with &amp;lt;85%, 85%-95%, and ≥95% African ancestry were 134.7 ng/ml, 143.8 ng/ml, 147.8 ng/ml, and 147.4 ng/ml, respectively, while IGFBP-3 levels were 3871.8 ng/ml, 3816.9 ng/ml, 3629.0 ng/ml, and 3693.9 ng/ml, respectively. African American women with 85% African ancestry, but these differences in IGF-1 and IGFBP-3 levels between African American ancestry groups were not statistically significant. We also calculated the molar ratio of IGF-1 to IGFBP-3 as an index of biologically available or free IGF-1. Differences in free IGF-1 among white women and African American women with &amp;lt;85%, 85%-95%, and ≥95% African ancestry were 0.126,0.137,0.148, and 0.145, respectively. Free IGF-1 levels were significantly lower among African American women with &amp;lt;85% compared to women with 85%-95% (p=0.02) or ≥95% (p=0.05) ancestry. Conclusion: Estimates of African ancestry are significantly associated with IGF-2 and free IGF-1, and suggest inherited genetic traits associated with African ancestry contribute to racial differences in IGF levels. Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):PR-1.

A super-agonist of growth hormone–releasing hormone causes rapid improvement of nutritional status in patients with chronic kidney disease

Chronic kidney disease is frequently associated with protein-energy wasting related to chronic inflammation and a resistance to anabolic hormones such as insulin and growth hormone (GH). In this study, we determined whether a new GH-releasing hormone super-agonist (AKL-0707) improved the anabolism and nutritional status of nondialyzed patients with stage 4-5 chronic kidney disease randomized to twice daily injections of the super-agonist or placebo. After 28 days, this treatment significantly increased 24-h GH secretion by almost 400%, without altering the frequency or rhythmicity of secretory bursts or fractional pulsatile GH release, and doubled the serum insulin-like growth factor-1 level. There was a significant change in the Subjective Global Assessment from 'mildly to moderately malnourished' to 'well-nourished' in 6 of 9 patients receiving AKL-0707 but in none of 10 placebo-treated patients. By dual-energy X-ray absorptiometry, both the mean fat-free mass and the body mineral content increased, but fat mass decreased, all significantly. In the AKL-0707-treated group, both serum urea and normalized protein equivalent of nitrogen appearance significantly decreased with no change in dietary protein intake, indicating a protein anabolic effect of treatment. Thus, our study shows that stimulation of endogenous GH secretion by AKL-0707 overcomes uremic catabolism of patients with advanced chronic kidney disease.

Free insulin‐like growth factor (IGF)‐1 and IGF‐binding proteins‐2 and ‐3 in serum and cerebrospinal fluid of amyotrophic lateral sclerosis patients

The insulin-like growth factor-1 (IGF-1) signaling system is regulated by many factors which interact in regulating the bioavailability of IGF-I. In this context, little information is available on free IGF-1, the bioactive form of IGF-1, in amyotrophic lateral sclerosis (ALS). We investigated the endogenous expression of IGF-1, and two related binding proteins (IGF-binding proteins, IGFBP-2 and BP-3) in serum and cerebrospinal fluid (CSF) of 54 sporadic ALS (sALS) patients. Twenty-five healthy individuals and 25 with other neurological diseases (OND) were used as controls. Total and free IGF-1, and IGFBP-3 levels were detected by immunoradiometric assay (IRMA); IGFBP-2 levels were determined by radioimmunoassay (RIA). Total and free IGF-1, IGFBP-2 and BP-3 serum levels were not significantly different between patients and controls, although in sALS patients free IGF-1 was negatively correlated with ALS-Functional Rating Scale-revised (ALS-FRS-R) score (r = -0.4; P = 0.046) and forced vital capacity (FVC) (r = -0.55; P < 0.04). In CSF, free IGF-1 was significantly increased in sALS patients compared with OND (P < 0.0001). Though in the serum we did not find significant differences amongst the three groups, IGF-1 bioavailability, represented by the free IGF-1 levels, correlated with disease severity. In the CSF, the significant increment of the free fraction of IGF-1 suggests an up-regulation of the IGF-1 system in the intrathecal compartment of sALS patients. Since IGF-1 is a trophic factor for different tissues, we speculate that high levels of the free IGF-1 in sALS might reflect a physiological defensive mechanism promoted in response to neural degeneration and/or muscle atrophy.

Use of ACE inhibitors is associated with elevated levels of IGFBP-3 among hypertensive older adults: results from the IlSIRENTE study

Several studies in vitro or in rodent models have suggested a potential relationship between angiotensin-converting enzyme (ACE) inhibition and the insulin-like growth factor 1 (IGF-1) axis. However, this relationship has only rarely been investigated in humans. The aim of the present cross-sectional study was to assess the association of ACE inhibitors with free IGF-1 and IGFBP-3 in the blood of older hypertensive adults. Data are from the baseline evaluation of the IlSIRENTE study, which enrolled 364 subjects aged 80 or older. For the present study we selected a subpopulation of 264 hypertensive participants without congestive heart failure. Free IGF-1 and IGFBP-3 in the blood were measured by a radioimmunoassay method. Analyses of covariance were performed to evaluate the differences in free IGF-1 and IGFBP-3 levels according to the use of ACE inhibitors. The mean age of participants was 85.7 years (SD: 4.9), 170 (64%) were women and 123 (47%) were using an ACE inhibitor. Following adjustment for potential confounders, the concentration of free IGF-1 was slightly, but not significantly higher among ACE inhibitor users than among non-users (0.74 vs. 0.65 ng/mL; p=0.20). In contrast, ACE inhibitor users had a significantly higher IGFBP-3 serum levels than non-users (4821 vs. 4330 ng/mL; p=0.005). In addition, the concentration of IGFBP-3 was significantly higher among ACE inhibitors users than among non-users of antihypertensive drugs (p=0.02) and users of other antihypertensive drugs (p=0.01). Among hypertensive older adults, ACE inhibitors use is associated with higher IGFBP-3 levels.

Free Insulin-Like Growth Factor-1 Levels in Bladder Growth following Spinal Cord Injury Experimentally

Introduction: To determine the levels of spinal cord injury (SCI) on free insulin-like growth factor-1 (IGF-1) content in the bladder and the possible role of free IGF-1 in growth in hypertrophic bladders in an experimental model. Materials and Methods: The contents of free IGF-1 and protein in paraplegic and non-paraplegic rats which was induced experimentally by SCI were measured. The wet weights of the bladders were also determined. The results gained were compared. Results: The mean bladder free IGF-1 level in paraplegic rats was significantly higher than the corresponding bladder free IGF-1 level in sham-operated bladder (p < 0.05). Mean wet weight bladder in paraplegic rats was significantly higher than the sham-operated rats (p < 0.05). Paraplegic bladder had a significantly higher mean protein content than the sham-operated bladder (p < 0.05). Serum free IGF-1 levels in the two groups were not different. Conclusion: Our pilot study reveals that free IGF-1 may be effective in SCI.