Low Insulin-like Growth Factor-1 Research Articles

Can the reduced GH, IGF-1, and ovarian steroids concentrations be considered as suspected biomarkers of age-associated functional deficit in mares?

In humans' and experimental animals’ components of the somatotropic axis, such as growth hormone (GH) and insulin-like growth factor 1 (IGF-1) concentrations, decrease with advancing age. Although there is evidence regarding IGF-1, the effect of age on GH in mares, as well as the relationships between both parameters, have not yet been elucidated. On the other hand, although GH and IGF-1 are related to follicular development, it is unknown if they could be correlated with the circulating concentrations of ovarian steroids in mares, as occurs in other species. The hypothesis of this study was that both GH and IGF-1 could experience physiological changes with advancing age also in mares, and that both GH/IGF-1 could be correlated with oestradiol-17β (E2) and progesterone (P4), as recorded for other species. Hence, the objective of this study was to evaluate the concentrations of GH, IGF-1, E2, and P4 in mares, according to the different ages. Blood samples were drawn from 56 healthy cyclic Spanish Purebred mares belonging to four different age groups: 6–9 years, 10–13 years, 14–16 years and >16 years. Mares aged 6–9 years and 10–13 years showed higher GH concentrations (P < 0.05) than mares of 14–16 and >16 years; and mares aged 14–16 showed higher GH concentrations (P < 0.05) than >16 years (P < 0.05). Mares aged >16 years showed lower IGF-1 concentrations (P < 0.05) than mares of 6–9, 10–13 and 14–16 years (P < 0.05). The concentrations of E2 and P4 showed no significant differences among different age groups. Both GH and IGF-1 were not correlated with each other or with E2 and P4. The concentrations of E2 and P4 did not change with age. Advancing age leads to a decrease in the activity of the somatotropic axis in physiological cyclic mares, represented by a significant GH reduction, which, however, was ascribed for IGF-1 exclusively to mares over 16 years of age, without alterations in steroid hormone patterns.

Assessment of Anthropometric and Pubertal Growth of Children and Adolescents with Type 1 Diabetes Mellitus

Abstract Background Type 1 diabetes mellitus (T1DM) is a wasting disease which is characterized by a severe deficiency or absence of insulin. It can interfere with growth and pubertal development, especially in uncontrolled patients with diabetes. Aim of the Work Our primary aim was to assess the anthropometric measures and pubertal growth of children and adolescents with T1DM regularly attending Pediatric and Adolescents Diabetes Unit (PADU), Ain Shams University. Our secondary aim was to detect risk determinants affecting these measures and their link to glycemic control. Patients and Methods This cross-sectional observational study was carried out on 200 children and adolescents with T1DM attending the PADU clinic. Patients were assessed using anthropometric measurements, lipid profile (Fasting serum triglycerides, total cholesterol, HDL and LDL) and HbA1c%. Those with short stature were further evaluated using insulin like growth factor1 (IGF1), bone age, lipid profile and thyroid profile. while those with delayed puberty were evaluated using sex hormones. Results we found that 12.5% of our patients were short (SD&amp;lt;-2), Cut off point of IGF-1 SDS (≤ -1.2) and GF1( 2ng/ml) was low in72% of them. Diabetic patients with short stature have significantly earlier age of onset of diabetes, earlier age at diagnosis and longer duration of diabetes compared to those with normal stature (P &amp;lt; 0.05). Additionally, patients with short stature and those with delayed puberty have higher HbA1c. Patients with short stature also have higher lipid profile and lower IGF1 compared to those with normal stature (p &amp;lt; 0.05). Conclusion Children with uncontrolled T1DM are at risk of being short and had delayed puberty. IGF-1 level can be used as a screening test for short stature in diabetic children.

Serum insulin-like growth factor-1 and leptin concentrations in Black Bengal goats at different ages and gestation periods and their relationship to kid growth performance.

The impact of maternal hormone concentration on kid growth performance in relation to insulin-like growth factor 1 (IGF-1) and leptin is minimal. This study examined IGF-1 and leptin levels at varying ages and gestation periods for their correlation with Black Bengal goat kids' growth during the preweaning phase. Blood samples were collected from 43 dams with different reproductive cycles and 28 prepubertal goats to measure serum concentrations of IGF-1 and leptin. Among dams, both hormones were investigated in different age ranges (<2, 2-3, 3-4, and >4 years old) and reproductive cycles (non-pregnancy, early gestation (1-50 days), mid-gestation (51-100 days), late gestation (101-135 days), and the last 15 days before delivery). After delivery, 65 kids from 34 dams were weighted weekly for 8 weeks to calculate average daily weight gain (ADG) at 0-4 weeks (ADG0-4 W) and 4-8 weeks (ADG4-8 W) and growth performance, including weight (W), height (H), length (L), chest girth (C) measured at birth (W0, H0, L0, and C0) and at 10 weeks of age (W10, H10, L10, and C10) were related to hormone serum concentrations in their dams at different gestation periods including the last 15 days before delivery. Dams had higher mean serum IGF-1 (p < 0.001) and leptin (p < 0.05) than prepubertal goats. Dams at late gestation had higher IGF-1 concentrations than those at early and mid-gestation and during the last 15 days before delivery. However, it was consistent with non-pregnant goats. The kid's growth performance correlated positively with IGF-1 concentration, which was collected in the last 15 days before delivery. Multivariate analysis showed that ADG0-4 W was higher in kids born from dams with high IGF-1 than those with low IGF-1 measured during the last 15 days of delivery, whereas leptin tended to have a similar effect. Serum IGF-1 and leptin concentrations of dams measured during the last 15 days before delivery were associated with kid's growth during the preweaning period.

The positive impact of smoking on poor sleep quality is moderated by IGF1 levels in cerebrospinal fluid: a case-control study among Chinese adults.

Previous research indicates associations between cigarette smoking, insulin-like growth factor-1 (IGF1), and sleep disturbances. This study aimed to examine the association between smoking and sleep quality and investigate the moderating role of IGF1. This case-control study involved 146 Chinese adult males (53 active smokers and 93 non-smokers) from September 2014 to January 2016. Sleep quality and disturbances were evaluated using the Pittsburgh Sleep Quality Index (PSQI), which includes seven scales. Pearson correlation analysis and logistic regression analysis were utilized to examine the link between IGF1 levels in cerebrospinal fluid (CSF) and PSQI scores. The effect of IGF1 was assessed using the moderation effect and simple slope analysis, with adjustments made for potential confounders. Active smokers exhibited significantly higher global PSQI scores and lower IGF1 levels in CSF compared to non-smokers. A significant negative correlation was observed between IGF1 and PSQI scores (â = -0.28, P < 0.001), with a stronger association in non-smokers (Pearson r = -0.30) compared to smokers (Pearson r = -0.01). Smoking was associated with higher global PSQI scores (â = 0.282, P < 0.001), and this association was moderated by IGF1 levels in CSF (â = 0.145, P < 0.05), with a stronger effect at high IGF1 levels (Bsimple = 0.402, p < 0.001) compared to low IGF1 levels (Bsimple = 0.112, p = 0.268). Four subgroup analysis revealed similar results for sleep disturbances (Bsimple = 0.628, P < 0.001), with a marginal moderation effect observed on subjective sleep quality (Bsimple = 0.150, P = 0.070). However, independent associations rather than moderating effects were observed between IGF1 and sleep efficiency and daytime disturbance. We provided evidence to demonstrate the moderation effect of IGF1 on the relationship between smoking and sleep in CSF among Chinese adult males.

Sex-based differences in growth-related IGF1 signaling in response to PAPP-A2 deficiency: comparative effects of rhGH, rhIGF1 and rhPAPP-A2 treatments

BackgroundChildren with pregnancy-associated plasma protein-A2 (PAPP-A2) mutations resulting in low levels of bioactive insulin-like growth factor-1 (IGF1) and progressive postnatal growth retardation have improved growth velocity and height following recombinant human (rh)IGF1 treatment. The present study aimed to evaluate whether Pappa2 deficiency and pharmacological manipulation of GH/IGF1 system are associated with sex-specific differences in growth-related signaling pathways.MethodsPlasma, hypothalamus, pituitary gland and liver of Pappa2ko/ko mice of both sexes, showing reduced skeletal growth, and liver of these mice treated with rhGH, rhIGF1 and rhPAPP-A2 from postnatal day (PND) 5 to PND35 were analyzed.ResultsReduced body and femur length of Pappa2ko/ko mice was associated with increases in: (1) components of IGF1 ternary complexes (IGF1, IGFBP5/Igfbp5, Igfbp3, Igfals) in plasma, hypothalamus and/or liver; and (2) key signaling regulators (phosphorylated PI3K, AKT, mTOR, GSK3β, ERK1/2 and AMPKα) in hypothalamus, pituitary gland and/or liver, with Pappa2ko/ko females having a more prominent effect. Compared to rhGH and rhIGF1, rhPAPP-A2 specifically induced: (1) increased body and femur length, and reduced plasma total IGF1 and IGFBP5 concentrations in Pappa2ko/ko females; and (2) increased Igf1 and Igf1r levels and decreased Ghr, Igfbp3 and Igfals levels in the liver of Pappa2ko/ko females. These changes were accompanied by lower phospho-STAT5, phospho-AKT and phospho-ERK2 levels and higher phospho-AMPK levels in the liver of Pappa2ko/ko females.ConclusionsSex-specific differences in IGF1 system and signaling pathways are associated with Pappa2 deficiency, pointing to rhPAPP-A2 as a promising drug to alleviate postnatal growth retardation underlying low IGF1 bioavailability in a female-specific manner.

Very low serum IGF-1 levels are associated with vertebral fractures in adult males with beta-thalassemia major.

Patients with beta-thalassemia major (BTM) often develop several endocrine disorders due to chronic iron overload. They are also prone to osteoporosis and vertebral fractures. Plasmatic insulin-like growth factor-1 (IGF-1) levels are often low in subjects with BTM, which origin is multifactorial. The aim of this study was to evaluate a possible relationship between serum IGF-1 levels and the presence of osteoporosis and/or vertebral fractures. We retrospectively evaluated the occurrence of vertebral fractures in 30 adult male patients affected by BTM (mean age 43.3 ± 7.9years) with low serum IGF-1 (median value 52.4ng/ml, 38.5-83.4). Only 6 of them (20.0%) were diagnosed with GH deficiency (GHD) after GHRH/arginine stimulation test, while 23 (76.7%) had osteoporosis and 12 (40.0%) had known vertebral fractures. All patients except one also showed at least one endocrine disorder. Serum IGF-1 was significantly lower in BTM patients with vertebral fractures compared to patients without vertebral fractures (U = 41.0, p = 0.005) while it was not significantly different between patients with low bone mass compared to patients without low bone mass. The diagnosis of GHD was significantly associated with lower serum IGF-1 (p = 0.001) and vertebral fractures (p = 0.002) but not with low bone mass. After ROC analysis, we found that very low IGF-1 (≤ 50.0ng/dl) was associated with vertebral fractures (sensitivity 83.3%, specificity 75.0%) and was also predictive of GHD (sensitivity 75.0%, specificity 100.0%). Our study shows that, in male patients with BTM, serum IGF-1 ≤ 50.0ng/dl is a marker of vertebral fractures and it is predictive of a diagnosis of GHD.

Early IGF-1 receptor inhibition in mice mimics preterm human brain disorders and reveals a therapeutic target.

Besides recent advances in neonatal care, preterm newborns still develop sex-biased behavioral alterations. Preterms fail to receive placental insulin-like growth factor-1 (IGF-1), a major fetal growth hormone in utero, and low IGF-1 serum levels correlate with preterm poor neurodevelopmental outcomes. Here, we mimicked IGF-1 deficiency of preterm newborns in mice by perinatal administration of an IGF-1 receptor antagonist. This resulted in sex-biased brain microstructural, functional, and behavioral alterations, resembling those of ex-preterm children, which we characterized performing parallel mouse/human behavioral tests. Pharmacological enhancement of GABAergic tonic inhibition by the U.S. Food and Drug Administration-approved drug ganaxolone rescued functional/behavioral alterations in mice. Establishing an unprecedented mouse model of prematurity, our work dissects the mechanisms at the core of abnormal behaviors and identifies a readily translatable therapeutic strategy for preterm brain disorders.

Association between Expression of Insulin-like Growth Factor-1 (IGF-1), IGF-1 Receptor (IGF-1R), and Hypertension-Mediated Organ Damage (HMOD) Parameters in Leukocytes and Plasma of Children/Adolescents with Primary Hypertension.

A decrease in IGF-1 is often linked to inflammation. Low systemic and local IGF-1 production and downregulation of IGF-1R expression may precede and predict PH development in children/adolescents. Leukocyte mRNA expression of IGF-1 and its receptor (IGF-1R) and plasma IGF-1 were measured in a group of 39 PH children/adolescents (29 boys and 10 girls) and 35 age-matched normotensive children (19 boys and 16 girls) using the RT-PCR and ELISA tests. The expression of the IGF-1R protein was assessed by flow cytometry. Plasma IGF-1 concentration was evaluated with ELISA. The expression of IGF-1 and IGF-1R and plasma concentrations of IGF-1 did not differ between groups. However, the PH children had a decreased percentage in IGF-1R-bearing lymphocytes (p = 0.02) and monocytes (p = 0.0003), as well as a low density of IGF-R in monocytes (p = 0.02). The IGF-1 expression was negatively correlated with pulse-wave velocity (PWV) (r = -0.49), systolic blood pressure (SBP) (-0.44), and carotid intima-media thickness (cIMT) (-0.43). The IGF-1R expression was negatively correlated with PWV (r = -0.42) and SBP (r = -0.41). Our results suggest that early subclinical hypertensive arterial injury is associated with lower activity of IGF-1-IGF-1R expression and loss of protective actions.

Asymmetric growth-limiting development of the female conceptus.

Sex differences in prenatal growth may contribute to sex-dependent programming effects on postnatal phenotype. We integrated for the first time phenotypic, histomorphological, clinico-chemical, endocrine and gene expression analyses in a single species, the bovine conceptus at mid-gestation. We demonstrate that by mid-gestation, before the onset of accelerated growth, the female conceptus displays asymmetric lower growth compared to males. Female fetuses were smaller with lower ponderal index and organ weights than males. However, their brain:body weight, brain:liver weight and heart:body weight ratios were higher than in males, indicating brain and heart 'sparing'. The female placenta weighed less and had lower volumes of trophoblast and fetal connective tissue than the male placenta. Female umbilical cord vessel diameters were smaller, and female-specific relationships of body weight and brain:liver weight ratios with cord vessel diameters indicated that the umbilico-placental vascular system creates a growth-limiting environment where blood flow is redistributed to protect brain and heart growth. Clinico-chemical indicators of liver perfusion support this female-specific growth-limiting phenotype, while lower insulin-like growth factor 2 (IGF2) gene expression in brain and heart, and lower circulating IGF2, implicate female-specific modulation of key endocrine mediators by nutrient supply. This mode of female development may increase resilience to environmental perturbations in utero and contribute to sex-bias in programming outcomes including susceptibility to non-communicable diseases.

Tmem263 deletion disrupts the GH/IGF-1 axis and causes dwarfism and impairs skeletal acquisition

Genome-wide association studies (GWAS) have identified a large number of candidate genes believed to affect longitudinal bone growth and bone mass. One of these candidate genes, TMEM263, encodes a poorly characterized plasma membrane protein. Single nucleotide polymorphisms in TMEM263 are associated with bone mineral density in humans and mutations are associated with dwarfism in chicken and severe skeletal dysplasia in at least one human fetus. Whether this genotype-phenotype relationship is causal, however, remains unclear. Here, we determine whether and how TMEM263 is required for postnatal growth. Deletion of the Tmem263 gene in mice causes severe postnatal growth failure, proportional dwarfism, and impaired skeletal acquisition. Mice lacking Tmem263 show no differences in body weight within the first 2 weeks of postnatal life. However, by P21 there is a dramatic growth deficit due to a disrupted growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis, which is critical for longitudinal bone growth. Tmem263-null mice have low circulating IGF-1 levels and pronounced reductions in bone mass and growth plate length. The low serum IGF-1 in Tmem263-null mice is associated with reduced hepatic GH receptor (GHR) expression and GH-induced JAK2/STAT5 signaling. A deficit in GH signaling dramatically alters GH-regulated genes and feminizes the liver transcriptome of Tmem263-null male mice, with their expression profile resembling wild-type female, hypophysectomized male, and Stat5b-null male mice. Collectively, our data validates the causal role for Tmem263 in regulating postnatal growth and raises the possibility that rare mutations or variants of TMEM263 may potentially cause GH insensitivity and impair linear growth.

Tmem263 deletion disrupts the GH/IGF-1 axis and causes dwarfism and impairs skeletal acquisition.

Genome-wide association studies (GWAS) have identified a large number of candidate genes believed to affect longitudinal bone growth and bone mass. One of these candidate genes, TMEM263, encodes a poorly characterized plasma membrane protein. Single nucleotide polymorphisms in TMEM263 are associated with bone mineral density in humans and mutations are associated with dwarfism in chicken and severe skeletal dysplasia in at least one human fetus. Whether this genotype-phenotype relationship is causal, however, remains unclear. Here, we determine whether and how TMEM263 is required for postnatal growth. Deletion of the Tmem263 gene in mice causes severe postnatal growth failure, proportional dwarfism, and impaired skeletal acquisition. Mice lacking Tmem263 show no differences in body weight within the first 2 weeks of postnatal life. However, by P21 there is a dramatic growth deficit due to a disrupted growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis, which is critical for longitudinal bone growth. Tmem263-null mice have low circulating IGF-1 levels and pronounced reductions in bone mass and growth plate length. The low serum IGF-1 in Tmem263-null mice is associated with reduced hepatic GH receptor (GHR) expression and GH-induced JAK2/STAT5 signaling. A deficit in GH signaling dramatically alters GH-regulated genes and feminizes the liver transcriptome of Tmem263-null male mice, with their expression profile resembling wild-type female, hypophysectomized male, and Stat5b-null male mice. Collectively, our data validates the causal role for Tmem263 in regulating postnatal growth and raises the possibility that rare mutations or variants of TMEM263 may potentially cause GH insensitivity and impair linear growth.

An exploratory study of clinical factors associated with IGF-1 and IGFBP-3 in preterm infants.

Despite advances in parenteral nutrition, postnatal growth failure in very low birthweight (VLBW) preterm infants is common and associated with chronic health problems. Insulin-like growth factor 1 (IGF-1) is positively associated with improved infant growth, but factors which promote IGF-1 levels in this population have not been clearly identified. The objective of this study was to explore early factors that influence IGF-1 in VLBW preterm infants. VLBW infants were enrolled into a prospective, randomized controlled nutrition trial (N = 87). Outcome measures included IGF-1 and IGFBP-3 levels measured at 35 weeks PMA. Linear regression analyses tested the relationships between candidate clinical predictors and levels of IGF-1 and IGFBP-3. Higher protein intake, longer duration of parenteral nutrition, and lower IGFBP-3 levels at 1 week of life were associated with lower IGF-1 levels at 35 weeks PMA. Neither early markers of insulin resistance nor degree of illness were associated with IGF-1 levels at 35 weeks PMA. Optimization of early nutrient intake, and attention to route of delivery, may have a lasting influence on IGF-1/IGFBP-3, and in turn, long-term health outcomes. In very low birthweight preterm infants, early protein intake, duration of parenteral nutrition, and insulin-like growth factor binding protein 3 (IGFBP-3) levels at 1 week of life are positively associated with insulin-like growth factor 1 (IGF-1) levels at 35 weeks postmenstrual age. Data from this study highlight the influence of early nutrition on components of the endocrine axis in preterm infants. Strategies aimed at early initiation of enteral nutrition, as well as optimizing composition of parenteral nutrition, may bolster hormones involved in promoting preterm infant growth.

There is currently no evidence that high serum leptin and low insulin-like growth factor-1 levels characterise fibromyalgia.

There is currently no evidence that high serum leptin and low insulin-like growth factor-1 levels characterise fibromyalgia.

THU028 Novel Approach To Management Of Acromegaly With De Novo Oral Octreotide Or Combination Therapy With Cabergoline: A Case Series

Abstract Disclosure: A. Halstrom: None. G.A. Dobri: None. Acromegaly is a rare disorder characterized by tumoral hypersecretion of growth hormone (GH) leading to overproduction of insulin-like growth factor 1 (IGF-1). Patients present with physical changes, and systemic complications. Treatment involves surgery and medical therapy with the goal of normalizing IGF-1. First line medical therapy consists of first-generation injectable somatostatin receptor ligands (SRL) (octreotide LAR, lanreotide autogel). Dopamine agonists (cabergoline) can be used in patients with mild IGF-1 elevation. If IGF-1 levels do not normalize, pasireotide or pegvisomant can be tried. Until recently, SRLs were administered only as a deep tissue injection. Patients have reported injection site reactions, frustration, and breakthrough acromegaly symptoms between doses. Two trials were conducted which showed that oral octreotide is an effective alternative for patients after achieving biochemical control with the injectable formulation. Two cases are presented below in which patients with acromegaly were treated with de novo oral octreotide either or as combination therapy with cabergoline, after a significant time lapse since injection SRL. Our first case is a 24 year old female with a 19mm mammosomatotroph adenoma, resected 8 years prior, with questionable remnant on postoperative MRI and biochemically active acromegaly. She was started on octreotide LAR 20mg which was titrated up to 30mg. However, she had not achieved biochemical control, with lowest IGF-1 543ng/mL (83-456ng/mL), Z-score 2.4, and GH 5.8ng/mL (&amp;lt;= 7.1ng/mL). She wanted a break from medical therapy and discontinued octreotide LAR. She was later started on pegvisomant 15mg but stopped after 10 days due to an allergic reaction and was switched to cabergoline. Cabergoline was up titrated to 3.5mg weekly, still without biochemical control, IGF-1 417ng/mL (103-326ng/mL), Z-score 2.5, GH 7.69ng/mL (0.05-8ng/mL), at which time oral octreotide 20mg twice daily was started and cabergoline decreased to 2.5mg weekly. Oral octreotide was increased to 60mg daily and IGF-1 levels normalized to 294ng/mL (83-456ng/mL), Z-score 1. The second case is a 70 year old female with type 2 diabetes, arthritis, left ventricular hypertrophy, obstructive sleep apnea and colon polyps found to have a 10mm pituitary adenoma with IGF-1 481ng/mL (32-238ng/mL), Z-score 3.1, GH 1.28ng/mL (0.05-8ng/mL). She declined surgical resection and opted for medical management. Oral octreotide 20mg twice daily was started and further increased to 60mg daily IGF-1 went as low as 327ng/mL (28-231ng/mL), Z-score 2.5 and GH 0.4ng/mL (0.05-8ng/mL). The dose was increased to 80 mg daily are lab results are pending. These are the first two published cases describing a novel approach to treating acromegaly in which patients were found to have a biochemical response to de novo oral octreotide either alone or combined with cabergoline. Presentation: Thursday, June 15, 2023

A-049 Inter-assay Variation of Insulin-like Growth Factor-1 Remains an Issue

Abstract Background Human insulin-like growth factor-1 (IGF-1) is the main mediator of the somatotropic effects of growth hormone (GH). Accurate measurement of IGF-1 is required for the diagnosis and management of GH secretion disorders. Several commercial vendors and laboratories have standardized their IGF-1 assays to the WHO International Standard 02/254. This standardization does not prohibit the existence of significant inter-assay variability in IGF-1 measurements. Such concentration variance can lead to inaccurate patient case decision making. The IGF-1 testing performed in our laboratory was recently migrated from an Immulite 2000 platform to a CobasPro system. This shift in vendor necessitated an investigation of the inter-assay variability between these standardized tests. This relative variance was established through a validation of the analytical performance of the CobasPro IGF-1 assay. Methods Reportable range, intra-day precision and accuracy of IGF-1 measurements using the CobasPro (Roche Diagnostics) system were determined. Patient correlation studies between the CobasPro and an Immulite 2000 (Siemens Healthcare Diagnostics) instrument was also performed. The concentration of IGF-1 in a subset of these correlation study specimens was also quantified by liquid chromatography mass spectrometry (LC-MS) assays from two different reference laboratories. Results The CobasPro assay had a verified linear range of 7–1443 ng/mL (R2 = 0.9998, slope = 0.9915). At IGF-1 concentrations of 54 and 345 ng/mL the intra-day precision (%CV, N = 10) of the CobasPro assay did not exceed 0.9%. Patient specimen correlations between the CobasPro and Immulite 2000 assays showed significant bias (Deming regression: y = 1.543x − 48.61, N = 128, R = 0.9641). This method bias was exacerbated at Immulite 2000 derived IGF-1 concentrations &amp;gt;100 ng/mL (Deming regression: y = 1.662x − 84.29, N = 93, R = 0.9492, CobasPro range = 77–910 ng/mL, Immulite 2000 range = 103–539 ng/mL). Patient specimen correlations between the CobasPro and LC-MS assay from reference laboratory A showed a positive bias (Deming regression: y = 1.375x − 64.5, N = 19, R = 0.9210). An analogous correlation with reference laboratory B demonstrated a higher level of concordance (Deming regression: y = 1.005x + 10.2, N = 16, R = 0.9499). The CobasPro and Immulite 2000 assays both produced acceptable result when challenged by multiple external quality assurance (EQA) specimens provided by the College of American Pathologists (CAP). However, the observed relative trends in IGF-1 concentrations from these challenges were opposite to our observations with authentic patient specimens. The CobasPro assay consistently produced lower IGF-1 concentrations relative to the Immulite 2000 assay for these EQA specimens. Conclusion The CobasPro IGF-1 assay offered acceptable analytical performance. Although both assays were traceable to a reference standard, a significant positive concentration bias was observed between the CobasPro and Immulite 2000 assays. Standardization efforts have not eliminated inter-assay IGF-1 variability. A careful evaluation of the impact of this variance on the diagnosis and management of GH deficiency and acromegaly must be considered when IGF-1 testing platforms are changed.

Method Validation and Establishment of Reference Intervals for an Insulin-like Growth Factor-1 Chemiluminescent Immunoassay in Cats.

Previously, radioimmunoassay (RIA) has been the only assay to measure insulin-like growth factor-1 (IGF-1) to diagnose hypersomatotropism (HS). Due to radiation concerns, availability, and the cost of IGF-1 RIA, validation of assays for automated analysers such as a chemiluminescent immunoassay (CLIA) is needed. The aim of this study was to validate a CLIA for measurement of feline IGF-1 (IMMULITE 2000® XPi, Siemens Medical Solutions Diagnostics, Malvern, PA, USA) compared to IGF1 RIA, establish reference interval (RI), and determine a cut-off value for diagnosis of HS in diabetic cats. Validation of assay performance included precision, linearity, and recovery studies. Right-sided RI was determined using surplus serum of 50 healthy adult cats. Surplus serum samples of diabetic cats with known IGF-1 concentration with (n = 32/68) and without HS (n = 36/68) were used for method comparison with RIA. The cut-off for diagnosis of HS was established using receiver operating characteristic (ROC) analysis. The intra-assay coefficient of variation (CV) was ≤4.7%, and the inter-assay CV was ≤5.6% for samples with low, medium, and high IGF-1 concentration. Linearity was excellent (R2 > 0.99). The correlation between CLIA and RIA was very high (rs = 0.97), with a mean negative bias for CLIA of 24.5%. The upper limit of RI was 670 ng/mL. ROC analysis showed an area under the curve of 0.94, with best cut-off for diagnosis of HS at 746 ng/mL (sensitivity, 84.4%; specificity, 97.2%). The performance of CLIA was good, and the RI and cut-off for HS diagnosis established in this study allow for CLIA to be used in routine work-up of diabetic cats.

Genetic scores associated with favourable and unfavourable adiposity have consistent effect on metabolic profile and disease risk across diverse ethnic groups.

This study aims to investigate the associations between genetic risk scores (GRS) for favourable and unfavourable adiposity and a wide range of adiposity-related outcomes across diverse populations. We utilised previously identified variants associated with favourable (36 variants) and unfavourable (38 variants) adiposity to create GRS for each adiposity phenotype. We used summary statistics from 39 outcomes generated by the Pan-UKB genome-wide association studies Version 0.3, incorporating covariates such as age, sex and principal components in six populations: European (n = 420,531), African (6636), American (980), Central/South Asian (8876), East Asian (2709) and Middle Eastern (1599). The favourable adiposity GRS was associated with a healthy metabolic profile, including lower risk of type 2 diabetes, lower liver enzyme levels, lower blood pressure, higher HDL-cholesterol, lower triglycerides, higher apolipoprotein A, lower apolipoprotein B, higher testosterone, lower calcium and lower insulin-like growth factor 1 generally consistently across all the populations. In contrast, the unfavourable adiposity GRS was associated with an adverse metabolic profile, including higher risk of type 2 diabetes, higher random glucose levels, higher HbA1c, lower HDL-cholesterol, higher triglycerides, higher liver enzyme levels, lower testosterone, and higher C-reactive protein generally consistently across all the populations. The study provides evidence that the genetic scores associated with favourable and unfavourable adiposity have consistent effects on metabolic profiles and disease risk across diverse ethnic groups. These findings deepen our understanding of distinct adiposity subtypes and their impact on metabolic health.

Circulating insulin-like growth factor-1 and brain health: Evidence from 369,711 participants in the UK Biobank

BackgroundThe effects of insulin-like growth factor-1 (IGF-1) deficiency on cognitive decline have been consistently reported in animal studies, but the relationship between IGF-1 and human brain health remains controversial. Our study aimed to investigate the associations of serum IGF-1 concentrations with some brain-related disorders and neuroimaging features.MethodsThis prospective study included 369,711 participants (55.8 ± 8.1 years) from the UK biobank who had serum IGF-1 measured and were free from brain-related disorders of interest — dementia, stroke, and Parkinson’s disease (PD) — at enrollment (2006–2010). Restricted cubic splines and Cox proportional hazards models were used to detect the associations between IGF-1 concentrations and brain-related diseases. In addition, general linear regressions were applied to explore the relationship between IGF-1 concentrations and neuroimaging features (volumes of white matter, grey matter, and hippocampus and white matter hyperintensity) among a sub-sample of 36,458 participants with magnetic resonance imaging data collected since 2014.ResultsDuring a median follow-up of 12.6 years, a total of 4,857 dementia, 6,240 stroke, and 2,116 PD cases were documented. The dose–response analyses yielded U-shaped relationships between IGF-1 concentrations and risks of dementia and stroke (P < 0.001 for non-linearity), with the lowest risks at 18 nmol/L and 26 nmol/L, respectively. A positive linear relationship was observed between IGF-1 concentrations and risk of PD (P = 0.163 for non-linearity). Moreover, neuroimaging analyses showed that higher IGF-1 concentrations were associated with greater volumes of white matter (β = 2.98 × 10–4, P < 0.001) and hippocampus (β = 3.37 × 10–4, P = 0.002) and smaller white matter hyperintensity (β = -3.12 × 10–3, P < 0.001).ConclusionsApart from the diverse associations with neuroimaging features, both low and high IGF-1 concentrations are associated with increased risks of dementia and stroke and higher IGF-1 concentrations are linked to a higher risk of PD, highlighting the potential of IGF-1 as a biomarker for risk stratification of brain health.

Clinical Features and Outcome Analysis of Type B Insulin Resistance Syndrome: A Single-Center Study in China.

Type B insulin resistance syndrome (TBIRS) is a rare condition, for which effective treatment remains challenging. This work aimed to summarize the clinical characteristics of TBIRS and explore effective therapeutic strategies. The clinical manifestations, biochemical indices, and treatment of 8 patients (3 men and 5 women) with TBIRS from Peking Union Medical College Hospital were retrospectively analyzed and their clinical outcomes were evaluated. The average age of the patients was 49.5 ± 16.5 years, and the duration of the disease ranged from 2 months to 1 year. Seven patients with hyperglycemia had normal/lower triglycerides (TGs) and lower insulin-like growth factor 1 (IGF-1) levels. One patient complained of intractable hypoglycemia. Five patients had accompanied systemic lupus erythematosus, 2 had mixed connective tissue disease, and 1 had undifferentiated connective tissue disease. Five patients had acanthosis nigricans and 3 women of child-bearing age had hyperandrogenism. All 8 patients were treated with glucocorticoids combined with immunosuppressants, among whom, 5 received high-dose glucocorticoid pulse therapy followed by conventional-dose glucocorticoid therapy, all of whom achieved partial remission within 2 to 4 weeks. Among the 3 patients receiving conventional glucocorticoid therapy, 2 achieved partial remission within 2 to 4 weeks. Six patients were tracked for 10 weeks to 4 years; 4 and 2 achieved complete and partial remission, respectively. Decreased serum complement 3 and IGF-1 levels and normal/decreased TG levels act as striking biochemical features of TBIRS. High-dose glucocorticoid pulse therapy followed by conventional-dose long-term therapy combined with immunosuppressants achieves good clinical efficacy.

A rare case of SCHMID metaphyseal chondrodysplasia associated with hypothyroidism,growth hormone deficiency and celiac disease: case report.

The authors present a rare case of 4-year-2-month-old boy referred to our Unit for harmonious short stature, he had a waddling gait, subtle micromelia, and hyperlordosis, no special facies. The skeletal scan made the diagnosis of SCHMID metaphyseal chondrodysplasia. The first laboratory workup showed elevated thyroid stimulating hormone and anti-tissue transglutaminase immunoglobulin A. The duodenal biopsies confirmed the diagnosis of coeliac disease. Treatment of levothyroxine was initiated with a gluten-free diet .6 years later, his re-evaluation showed a low insulin-like growth factor 1 and low growth hormone peaks confirming the diagnosis of growth hormone deficiency, Growth hormone therapy was initiated with an adjusted dose of levothyroxine. Other causes of short stature should not be missed when diagnosing chondrodysplasia, and further investigations should be carried out to detect other concomitant disorders since metaphyseal chondrodysplasia is a rare cause for short stature while hypothyroidism and coeliac disease are relatively common.