Vitamin A deficiency and association between serum retinol and IGF-1 concentrations in Brazilian children with Down syndrome

Abstract Objective: To determine the prevalence of vitamin A deficiency (VAD) and serum concentrations of retinol, correlating them with IGF-1 concentrations in preschoolers with DS. Methods: Cross-sectional study was conducted on 47 children with DS aged 24 to 72 months, in Ribeirão Preto, Brazil. VAD was determined by the relative dose-response (RDR) test. Retinol serum concentration ≤ 0.70 μmol/L and IGF-1 serum concentration below the 3rd percentile for sex and age were considered to represent deficiency. C-reactive protein (CRP) was determined at the beginning of the study. Weight, height, and information about fever and/or diarrhea were obtained at the beginning of the study. Results: VAD prevalence was 25.5% (12/47), and 74.5% (35/47) of the children had deficient retinol before the intervention. CRP was not associated with VAD. Mean IGF-1 were 103.5 ng/mL (SD = 913) for the group with VAD and 116.3 ng/mL (SD = 54.9) for the group with no VAD (p-value = 0.85); 8.5% (4/47) of the children showed deficient IGF-1, but without VAD. No association was observed between VAD and IGF-1 deficiency. A moderate positive correlation was observed between pre-intervention retinol and IGF-1 (ρ = 0.37; p-value = 0.01). Conclusion: a high prevalence of VAD and deficient retinol was observed and there was a positive correlation between serum retinol and IGF-1.

Effects of vitamin e on the epithelial-mesenchymal transition in testicular development exposed to valproic acid / Efectos de la vitamina e en la interacción epitelio-mesenquimático en el desarrollo testicular expuesto a ácido valproico

SUMMARY: In testicular differentiation, somatic cells must adopt a specific destiny towards sustentacular, peritubular and interstitial cells, being fundamental for the morphogenesis of seminiferous tubules, mediated by morphogens such as Desert Hedgehog (DHH), insulin-like growth factor-1 (IGF-1) and fibroblastic growth factor 2 (FGF-2). Its alteration could be related to failures in the development mechanisms, such as those caused by valproic acid (VPA), which can be reversed with vitamin E (VE). The objective of the study was to evaluate the epithelial-mesenchymal transition (EMT) in the testicular development of mice exposed to VPA and VE. 12 groups of pregnant female mice were formed that were separated by days post-coital (dpc) at 12.5 dpc, 17.5 dpc and 6 weeks postnatal, each one subdivided into 4 groups of 5 pregnant women each. Subgroups received different treatments from the beginning to the end of gestation orally: 600 mg/kg of VPA, 600 mg/kg of VPA and 200 IU of VE, 200 IU of VE and the control group 0.3 mL of 0.9% physiological solution. Immunohistochemistry was performed for the detection of DHH, IGF-1 and FGF-2. Immunolocalization of DHH was observed in all stages, with more evident significant differences in integrated optical density (IOD) and percentage of immunoreaction area at 6 weeks postnatal, being lower in the VPA group. In IGF-1, lower intensity and distribution of immunostaining was observed in the fetal and pubertal stages in the VPA groups, a similar situation with FGF-2, but only evident at 17.5 dpc, with significant differences. These results demonstrate that VPA can alter EMT between somatic cells in testicular development, with VE being an agent capable of attenuating this process.

RESUMEN: En la diferenciación testicular, es necesario que las células somáticas adopten un destino específico hacia células sustentaculares, peritubulares e intersticiales, siendo fundamental para la morfogénesis de los túbulos seminíferos, mediado por morfógenos como Desert Hedgehog (DHH), Factor de Crecimiento Fibroblástico 2 (FGF-2) y Factor de Crecimiento símil a Insulina (IGF-1). Su alteración se podría relacionar a fallas en los mecanismos de desarrollo, como los que ocasiona el ácido valproico (VPA), los cuales pueden ser revertidos con la vitamina E (VE). El objetivo de estudio fue evaluar la transición epitelio-mesenquimática (EMT) en el desarrollo testicular de ratones expuestos a VPA y VE. Se conformaron 12 grupos de ratones hembra gestantes que se separaron por días post-coital (dpc) a los 12.5 dpc, 17.5 dpc y 6 semanas post-natal, cada uno subdividido en 4 grupos de 5 gestantes cada uno. Cada subgrupo recibió diferentes tratamientos desde el inicio hasta el término de la gestación vía oral: 600 mg/kg de VPA, 600 mg/kg de VPA y 200 UI de VE, 200 UI de VE y el grupo control 0,3 mL de solución fisiológica 0,9%. Se realizó técnica inmunohistoquímica para la detección de DHH, IGF-1 y FGF-2. Se observó la inmunolocalización de DHH en todos los estadios, con diferencias significativas más evidentes en la densidad óptica integrada (IOD) y porcentaje de área de inmunoreacción a las 6 semanas post-natal, siendo menor en el grupo VPA. En IGF-1, se observó en la etapa fetal y puberal menor intensidad y distribución de la marcación en los grupos VPA, situación similar con la inmunomarcación de FGF-2, pero sólo evidenciándose a los 17.5 dpc, con diferencias significativas. Estos resultados demuestran que el VPA puede alterar la EMT entre las células somáticas en el desarrollo testicular, siendo la VE un agente capaz de atenuar este proceso.

Is biochemical hypoglycemia necessary during an insulin tolerance test?

ABSTRACT Objective The insulin tolerance test (ITT) has been accepted as the gold standard test for assessing the integrity of the growth hormone (GH) - insulin-like growth factor (IGF-1) axis and the hypothalamic-pituitary-adrenal (HPA) axis. The goal of the test is to achieve clinical and biochemical hypoglycemia at a blood glucose level ≤ 40 mg/dL to effectively and correctly assess the HPA and GH-IGF-1 axes. In this study, the GH and cortisol responses of patients who achieved and failed to achieve biochemical hypoglycemia during an ITT were compared. Subjects and methods One hundred thirty-five patients with pituitary disorders were included in the study. Samples for blood glucose levels were obtained after clear symptoms of clinical hypoglycemia developed. The patients were enrolled in the hypoglycemic and nonhypoglycemic groups according to whether their plasma glucose level ≤ 40 mg/dL or > 40 mg/dL during an ITT, and the groups were compared in terms of their GH and cortisol responses. Results The mean age, body mass index and waist circumference of the two patient groups were found to be similar. The mean blood glucose level was significantly lower in the hypoglycemic group than in the nonhypoglycemic group (19.3 and 52.0 mg/dL, respectively). When the two groups were compared in terms of peak cortisol and GH responses, no statistically significant differences were found. Conclusion The data presented suggest that clinically symptomatic hypoglycemia is as effective as biochemically confirmed hypoglycemia during an ITT. Arch Endocrinol Metab. 2020;64(1):82-8

Effect of enhanced masticatory force on OPG, RANKL and MGF in alveolar bone of ovariectomized rats

Abstract Menopause induces oral bone loss, leading to various oral diseases. Mastication importantly affects bone metabolism in the jawbone. Objective: To analyze the effect of enhanced masticatory force on osteoprotegerin (OPG), receptor activator of nuclear factor kappa B ligand (RANKL), and mechano-growth factor (MGF) in alveolar bone of ovariectomized rats and to study the mechanics mechanism of the alveolar bone of ovariectomized rats response to enhanced masticatory force. Methodology: Thirty Sprague Dawley rats were randomly divided into three groups: sham-operation group (fat around the removed ovary + normal hard diet), model group (ovariectomy + normal hard diet), and experimental group (ovariectomy + high hard diet). It was a 2-month experiment. Enzyme-linked immunosorbent assay (ELISA) detected serum estradiol (E2), osteocalcin (BGP) and alkaline phosphatase (ALP) in rats. Bone histomorphometric indices in the third molar region of maxilla were detected by micro-CT; protein expressions of OPG, RANKL, and MGF in the third molar region of maxilla was detected by Western blot; and gene expression of OPG, RANKL, and MGF in the third molar region of maxilla was detected by Quantitative Real-Time PCR. Results: Comparing with model group, serum E2 in experimental group increased but not significantly, serum BGP and serum ALP in experimental group decreased but not significantly, OPG in experimental group in alveolar bone increased significantly, RANKL in experimental group in alveolar bone decreased significantly, RANKL/OPG ratio in experimental group decreased significantly, MGF in experimental group in alveolar bone increased significantly, bone volume to total volume fraction increased significantly in experimental group, trabecular thickness increased significantly in experimental group, and trabecular separation decreased significantly in experimental group. Conclusion: Enhanced masticatory force affected the expression of OPG, RANKL, and MGF in alveolar bone of ovariectomized rats, improved the quality of jaw bone of ovariectomized rats, and delayed oral bone loss by ovariectomy.

Laboratory investigations in the diagnosis and follow-up of GH-related disorders

ABSTRACT In addition to auxiological, clinical and metabolic features measurements of growth hormone (GH) and insulin-like growth factor I (IGF-I) complement our tools in diagnosis and follow-up of GH-related disorders. While comparably robust during the pre-analytical phase, measurement and interpretation of concentrations of both hormones can be challenging due to analytical issues and biological confounders. Assay methods differ in terms of antibody specificity, interference from binding proteins, reference preparations and sensitivity. GH assays have different specificity towards different GH-isoforms (e.g. 20 kDa GH, placental GH) and interference from the GH antagonist Pegvisomant. The efficacy to prevent binding protein interference is most important in IGF-I assays. Methodological differences between assays require that reference intervals and diagnostic cut-offs are assay-specific. Among biological variables, pubertal development and age are most relevant for IGF-I, making detailed reference intervals mandatory for interpretation. GH has pulsatile secretion and short half-life. Its concentration is modified by acute factors such as stress, exercise and sleep, but also by intake of oral estrogens and anthropometric factors (e.g. BMI). Other GH dependent biomarkers such as free IGF-I, IGF binding protein 3 (IGFBP 3) and acid labile subunit (ALS) have been proposed. Their concentrations largely mirror the information obtained through measurement of IGF-I, but their measurement can be helpful in particular situations. In this review, we describe the evolution of analytical methods to measure biomarkers of GH action, the impact of the methodological changes on laboratory results and the need to include biological variables in their interpretation. Arch Endocrinol Metab. 2019;63(6):618-29

Brazilian multicenter study on pegvisomant treatment in acromegaly

ABSTRACT Objective Investigate the therapeutic response of acromegaly patients to pegvisomant (PEGV) in a real-life, Brazilian multicenter study. Subjects and methods Characteristics of acromegaly patients treated with PEGV were reviewed at diagnosis, just before and during treatment. All patients with at least two IGF-I measurements on PEGV were included. Efficacy was defined as any normal IGF-I measurement during treatment. Safety data were reviewed. Predictors of response were determined by comparing controlled versus uncontrolled patients. Results 109 patients [61 women; median age at diagnosis 34 years; 95.3% macroadenomas] from 10 Brazilian centers were studied. Previous treatment included surgery (89%), radiotherapy (34%), somatostatin receptor ligands (99%), and cabergoline (67%). Before PEGV, median levels of GH, IGF-I and IGF-I % of upper limit of normal were 4.3 µg/L, 613 ng/mL, and 209%, respectively. Pre-diabetes/diabetes was present in 48.6% and tumor remnant in 71% of patients. Initial dose was 10 mg/day in all except 4 cases, maximum dose was 30 mg/day, and median exposure time was 30.5 months. PEGV was used as monotherapy in 11% of cases. Normal IGF-I levels was obtained in 74.1% of patients. Glycemic control improved in 56.6% of patients with pre-diabetes/diabetes. Exposure time, pre-treatment GH and IGF-I levels were predictors of response. Tumor enlargement occurred in 6.5% and elevation of liver enzymes in 9.2%. PEGV was discontinued in 6 patients and 3 deaths unrelated to the drug were reported. Conclusions In a real-life scenario, PEGV is a highly effective and safe treatment for acromegaly patients not controlled with other therapies.

Pituitary gigantism: a case series from Hospital de San José (Bogotá, Colombia)

ABSTRACT Introduction Gigantism is a rare pediatric disease characterized by increased production of growth hormone (GH) before epiphyseal closure, that manifests clinically as tall stature, musculoskeletal abnormalities, and multiple comorbidities. Materials and methods Case series of 6 male patients with gigantism evaluated at the Endocrinology Service of Hospital de San José (Bogotá, Colombia) between 2010 and 2016. Results All patients had macroadenomas and their mean final height was 2.01 m. The mean age at diagnosis was 16 years, and the most common symptoms were headache (66%) and hyperhidrosis (66%). All patients had acral changes, and one had visual impairment secondary to compression of the optic chiasm. All patients underwent surgery, and 5 (83%) required additional therapy for biochemical control, including radiotherapy (n = 4, 66%), somatostatin analogues (n = 5, 83%), cabergoline (n = 3, 50%), and pegvisomant (n = 2, 33%). Three patients (50%) achieved complete biochemical control, while 2 patients showed IGF-1 normalization with pegvisomant. Two patients were genetically related and presented a mutation in the aryl hydrocarbon receptor-interacting protein (AIP) gene (pathogenic variant, c.504G>A in exon 4, p.Trp168*), fulfilling the diagnostic criteria of familial isolated pituitary adenoma. Conclusions This is the largest case series of patients with gigantism described to date in Colombia. Transsphenoidal surgery was the first-choice procedure, but additional pharmacological therapy was usually required. Mutations in the AIP gene should be considered in familial cases of GH-producing adenomas.

Pegvisomant in acromegaly: a multicenter real-life study in Argentina

ABSTRACT Objective To describe the long term safety and efficacy of pegvisomant (PEGV), and the predictors of treatment response in patients with acromegaly in the real life setting. Subjects and methods We retrospectively reviewed the clinical, hormonal and radiological data of acromegalic patients treated with PEGV in 17 Argentine centers. Results Seventy-five patients (age range 22-77, 51 females) with acromegaly have been treated with PEGV for up to 118 months (median 27 months). Before PEGV, 97.3% of patients had been treated with medical therapy, surgery and/or radiotherapy, two patients had no previous treatment. At that time, all patients had an IGF-1 above the upper normal limit (ULN) (mean 2.4 x ULN ± 0.98, range 1.25-7). At diagnosis of acromegaly 84% presented macroadenomas, prior to PEGV only 23,5% of patients remained with tumor remnant > 1 cm, the remaining showed normal or less than 1 cm images. Disease control (IGF-1 ≤ 1.2 x ULN) was achieved in 62.9% of patients with a mean dose of 11.8 mg/day. Thirty-four patients (45%) received PEGV monotherapy, while 41 (55%) received combined therapy with either somatostatin analogues and/or cabergoline. Adverse events related to PEGV were: local injection site reaction in 5.3%, elevated liver enzymes in 9.3%, and tumor size growth in 9.8%. Pre-PEGV IGF-I level was the only predictor of treatment response: 2.1 x ULN vs 2.8 x ULN in controlled and uncontrolled patients respectively (p < 0.001). Conclusion this long term experience indicates PEGV treatment was highly effective and safe in our series of Argentine patients with acromegaly refractory to standard therapies. Arch Endocrinol Metab. 2019;63(4):320-7

Características de carcaça, órgão vomeronasal, concentrações séricas de testosterona e IGF-I em machos Nelore com ductos incisivos bloqueados / Characteristics of carcass, vomeronasal organ, serum testosterone and IGF-I concentrations in Nellore males with blocked incisor ducts

Objetivou-se avaliar características quali - quantitativas da carcaça em machos Nelore, submetidos ao bloqueio dos ductos incisivos no período pré puberal. Além disso, objetivou-se avaliar as concentrações séricas de testosterona e do hormônio do crescimento semelhante a insulina do tipo I (IGF-I), e a arquitetura histológica do órgão vomeronasal (OVN). Trinta e quatro machos, no período pré puberal, foram divididos em três grupos experimentais: inteiros ­ animais controle sem qualquer procedimento (n = 11); bloqueados - animais com os ductos incisivos bilateralmente obstruídos (n = 10); castrados - animais com orquiepididectomia bilateral (n = 13). O OVN foi obtido no abate, ao final do experimento, para avaliação histomorfométrica. As coletas de sangue foram realizadas a cada três meses, em dois turnos (manhã e tarde), totalizando cinco avaliações. Observaram-se maiores (P<0,05) pesos corporais finais (inteiros = 494,1 ± 28,71; bloqueados = 500,6 ± 23,6 e castrados = 468,3 ± 21,8 Kg) nos inteiros e bloqueados. O acabamento da carcaça foi maior nos castrados (P<0,05) em relação aos inteiros e bloqueados, enquanto o rendimento de carcaça não apresentou diferenças entre os três tratamentos (P>0,05). Registrou-se redução da altura do epitélio neuro sensitivo do OVN nos bloqueados e castrados (P<0,05). Foi registrada menor concentração de testosterona nos bloqueados nas coletas quatro e cinco à tarde (P<0,05). Conclui-se que a obstrução dos ductos incisivos reduziu os estímulos sensoriais para o OVN, que por sua vez, promoveu alteração na concentração sérica de testosterona, sem alterar o ganho de peso dos animais, porém, não promoveu melhoria na qualidade da carcaça nas condições deste estudo.

A total of 34 prepuberal Nellore males were divided into three groups: control ­ animals without any procedure (n = 11); blocked - with bilaterally incisors ducts obstructed (n = 10); castrated - with bilateral orchiectomy (n = 13). This study aimed to evaluate the effect of blocking the vomeronasal organ (VNO) in qualitative and quantitative characteristics of the carcass. Also, this study aimed to evaluate testosterone and insulin-like growth factor (IGF-I) serum concentration, and the histological architecture of the OVN. Blood samples were taken every three months during two daily collections (morning and afternoon), totalizing five evaluations. It was observed higher (P<0.05) final body weight (control= 494.1 ± 28.71; blocked = 500.6 ± 23.6; castrated = 468.3 ± 21.8 kg) at the control and blocked groups. Carcass finishing was higher in castrated animals (P <0.05), while carcass yield did not differ between treatments (P> 0.05). It was observed a reduction (P<0.05) of the VNO sensory epithelium height in blocked and castrated groups compared with control group. It was registered lower (P<0.05) serum testosterone concentration in blocked group at the fourth and fifth blood collection (afternoon). It was concluded that the obstruction of the incisive ducts reduced the sensorial stimuli for the OVN, which, in turn, promoted a change in the serum concentration of testosterone, without altering the weight gain of the animals, but did not promote improvement in the quality of the carcass under the conditions of this study.

Acromegalia y silla turca vacía: una asociación infrecuente: presentación de un caso / Acromegaly and empty sella syndrome: an infrequent association: presentation of a case

La acromegalia, originada por un exceso de producción de Hormona de crecimiento (Gh), se caracteriza por crecimiento somático exagerado, alto riesgo cardio-metabólico, así como reducción de la expectativa de vida. Tiene una incidencia de 3-4 casos por millón de habitantes. El diagnóstico se retrasa hasta 10 años aumentando la morbi-mortalidad. Las alternativas terapéuticas incluyen medicamentos y cirugía, que van encaminados a reducir los efectos de masa tumoral, normalizar los parámetros bioquímicos y resolver las manifestaciones clínicas. En casos muy infrecuentes, el tumor hipofisario que la origina se asocia a silla turca vacía.

Acromegaly, caused by an excess production of growth hormone (Gh), it is characterized by exaggerated somatic growth, high cardio-metabolic risk, as well as reduction of life expectancy. It has an incidence of 3-4 cases per million population. The diagnosis is delayed up to 10 years increasing morbidity and mortality. The therapeutic alternatives include medications and surgery, which are aimed at reduce the effects of tumor mass, normalize biochemical parameters and resolve clinical manifestations. In very infrequent cases, the pituitary tumor that originates it is associated with empty sella syndrome. Key words: Acromegaly, Empty sella syndrome, Pituitary tumor.

Clinical and functional variables can predict general fatigue in patients with acromegaly: an explanatory model approach

ABSTRACT Objective To evaluate whether hormonal profile, arterial function, and physical capacity are predictors of fatigue in patients with acromegaly. Subjects and methods: This is a cross-sectional study including 23 patients. The subjects underwent a Modified Fatigue Impact Scale (MFIS) assessment; serum growth hormones (GH) and IGF-1 measurements; pulse wave analysis comprising pulse wave velocity (PWV), arterial compliance (AC), and the reflection index (IR1,2); dominant upper limb dynamometry (DYN); and the six-minute walking distance test (6MWT). Multiple linear regression models were used to identify predictors for MFIS. The coefficient of determination R2 was used to assess the quality of the models' fit. The best model was further analyzed using a calibration plot and a limits of agreement (LOA) plot. Results The mean ± SD values for the participants' age, MFIS, PWV, AC, IR1,2, DYN, and the distance in the 6MWT were 49.4 ± 11.2 years, 31.2 ± 18.9 score, 10.19 ± 2.34 m/s, 1.08 ± 0.46 x106 cm5/din, 85.3 ± 29.7%, 33.9 ± 9.3 kgf, and 603.0 ± 106.1 m, respectively. The best predictive model (R2 = 0.378, R2 adjusted = 0.280, standard error = 16.1, and P = 0.026) comprised the following regression equation: MFIS = 48.85 - (7.913 × IGF-I) + (1.483 × AC) - (23.281 × DYN). Conclusion Hormonal, vascular, and functional variables can predict general fatigue in patients with acromegaly.

Correlation analysis between short-term insulin-like growth factor-I and glucose intolerance status after transsphenoidal adenomectomy in acromegalic patients: a large retrospective study from a single center in China

ABSTRACT Objectives: Our study aimed to investigate the associations of glucose tolerance status with insulin-like growth factor-I (IGF-I) and other clinical laboratory parameters of acromegalic patients before and after the patients underwent transsphenoidal adenomectomy (TSA) by conducting a single-center, retrospective study. Subjects and methods: A total of 218 patients with acromegaly who had undergone TSA as the first treatment were retrospectively analyzed. Serum IGF-I, growth hormone (GH) and glucose levels were measured before and after surgery. Results: The follow-up levels for random GH, GH nadir, and the percentage of the upper limit of normal IGF-I (%ULN IGF-I) were decreased significantly. The percentages of normal (39.0%), early carbohydrate metabolism disorders (33.0%) and diabetes mellitus (28.0%) changed to 70.2%, 16.5% and 13.3%, respectively, after TSA. %ULN IGF-I at baseline was higher in the diabetes mellitus (DM) group than in the normal glucose tolerance group and impaired glucose tolerance (IGT) /impaired fasting glucose (IFG) groups before TSA, and the DM group exhibited a greater reduction in %ULN IGF-I value after surgery. The follow-up %ULN IGF-I value after surgery was significantly lower in the improved group, and Pearson's correlation analysis revealed that the reductions in %ULN IGF-I corresponded with the reductions in glucose level. Conclusion: This study examined the largest reported sample with complete preoperative and follow-up data. The results suggest that the age- and sex-adjusted IGF-I level, which reflects altered glucose metabolism, and the change of it are associated with improved glucose tolerance in acromegalic patients both before and after TSA.

Padronização da quantificação do fator de crescimento semelhante à insulina I (IGF-I) em plasma bovino por ELISA / Standardization of ELISA for the measurement of Insulin-Like Growth Factor I (IGF-I) in bovine plasm

Esse estudo teve como objetivo a padronização de um ensaio imunoenzimático competitivo (cELISA) in house para a determinação das concentrações plasmáticas do fator de crescimento semelhante a insulina I (IGF-I) total para a espécie bovina, utilizando o sistema de amplificação biotina-estreptavidina peroxidase. O IGF-I foi extraído das proteínas ligadoras do fator de crescimento semelhante a insulina I (IGFBP), utilizando o tampão glicina acidificado seguido de neutralização do pH com hidróxido de sódio. As microplacas foram sensibilizadas com anti IgG de coelho, e as dosagens realizadas utilizando duas abordagens, um método com incubação prévia das amostras com o anticorpo anti-h-IGF-I e outro sem incubação prévia (adição simultânea de IGF-I biotilinado e amostra). Os melhores resultados foram obtidos utilizando o método sem incubação prévia, com a sensibilização da placa com 0,25µg/poço de anti-IgG de coelho, o anticorpo específico na diluição 1:250.000 e 0,06ng/poço de IGF-I biotinilado. O ensaio in house apresentou um limite inferior de detecção de 50ng/mL, uma correlação de 0,945 entre doses quando comparado a uma metodologia comercial. Os coeficientes de variação inter-ensaio de 12,94% (345,8ng/mL) para os controles alto e 20,71% (131,6ng/mL) para o baixo. Dessa forma, conclui-se que a metodologia imunoenzimática para quantificação de IGF-I total utilizando o sistema de amplificação biotina-estreptavidina peroxidase em um ensaio competitivo está estabelecida e apresenta-se como uma ferramenta útil para estudos que visem o monitoramento das concentrações de IGF-I.(AU)

This study aimed to standardize an in house competitive enzyme-linked immunosorbent assay (cELISA) to determine plasma concentrations of total insulin-like growth factor I (IGF-I) for the bovine specie using the amplification biotin-streptavidin peroxidase system. The IGF-I was extracted from insulin-like growth factor binding proteins (IGFBPs) using the acidified glycine buffer followed by the pH neutralization with sodium hydroxide. The microplates were coated with anti-rabbit IgG, thereafter the measurements were carried out using two approaches, one with a prior incubation of samples with the anti-h-IGF-I antibody and another without previous incubation (simultaneous addition of IGF-I and biotinylated sample). The best results were obtained using the method without the prior incubation, using the following combination of reagents: microplates were coated with 0.25µg/well of anti-rabbit IgG, the specific antibody at a dilution of 1:250,000 and 0.06ng/well of biotinylated IGF-I. The in house methodology showed sensitivity of 50ng/ml, a correlation between doses of 0.945 when compared to a commercial method. In addition, after 33 assays (quantification of 1114 samples) the proposed methodology presented a good precision, with inter-assay variation coefficients of 12.94% and 20.71% for the high and low controls, respectively. Finally, we concluded that ELISA method for the quantification of total IGF-I using the system biotin-streptavidin-peroxidase amplification in a competitive assay is established and is presented as a useful tool for studies aimed at monitoring the IGF-I concentrations.(AU)

Long-term follow-up of patients with elevated IGF-1 and nadir GH > 0 4 µg/L but < 1 µg/L

ABSTRACT Objective To report the results of initial investigation and after 5 years of patients with a suspicious clinical scenario for acromegaly, elevated IGF-1, and nadir GH during an oral glucose tolerance test (OGTT) > 0.4 µg/L but < 1 µg/L. Subjects and methods Seventeen patients who had elevated IGF-1 (outside puberty and pregnancy) in two measurements and GH between 0.4 and 1 µg/L during OGTT were selected. Results During initial assessment, only one patient had microadenoma on magnetic resonance imaging (MRI) of the pituitary. In this patient, IGF-1 returned to normal spontaneously after 5 years. In the remaining 16 patients, spontaneous normalization of IGF-1 was observed in four and IGF-1 continued to be elevated in 12 after 5 years. None of the latter patients developed a phenotype of acromegaly, changes in physiognomy or increase in IGF-1 and no tumor was detected by imaging methods. Two patients had nadir GH < 0.4 µg/L, while the nadir GH remained between 0.4 and 1 µg/L in 10 patients. Conclusion In patients (notably young adult or adult women) without a typical phenotype in whom IGF-1 is measured due to a suspicious clinical scenario and is found to be slightly elevated, even if confirmed and in the absence of other causes, a nadir GH cut-off value of 0.4 µg/L instead of 1 µg/L in the OGTT might be inadequate for the diagnosis.

Treatment of acromegaly patients at the Federal University of Triângulo Mineiro (UFTM): Experience Report

OBJECTIVE: To evaluate the effectiveness of the treatment of acromegaly patients at the Federal University of Triangulo Mineiro. METHODS: Cross-sectional and retrospective study of thirty cases treated over a period of two decades. RESULTS: 17 men (56.7%) aged 14-67 years and 13 women aged 14-86 years were analyzed. Twenty-one patients underwent transphenoidal surgery, whichwas associated with somatostatin receptor ligands in 11 patients (39.3%), somatostatin receptor ligands + radiotherapyin 5 patients (17.8%), radiotherapy in 3 patients (10.7%), and radiotherapy + somatostatin receptorligands + cabergoline in 1 patient (3.6%). Additionally, 2 patients underwent radiotherapy and surgeryalone. Six patients received somatostatin receptor ligands before surgery, and 2 were not treated due to refusal and death. Nine patients have died, and 20 are being followed; 13 (65%) have growth hormonelevels o1 ng/mL, and 11 have normal insulin-like growth factor 1 levels. CONCLUSION: The current treatment options enable patients seen in regional reference centers to achieve strict control parameters, which allows them to be treated close to their homes.

Elevated IGF-1 with GH suppression after an oral glucose overload: incipient acromegaly or false-positive IGF-1?

ABSTRACT Objective To report the evolution of patients with a suggestive clinical scenario and elevated serum insulin-like growth factor-1 (IGF-1), but growth hormone (GH) suppression in the oral glucose tolerance test (OGTT), in whom acromegaly was not initially excluded. Subjects and methods Forty six patients with a suggestive clinical scenario, who had elevated IGF-1 (outside puberty and pregnancy) in two measurements, but GH < 0.4 µg/L in the OGTT, were selected. Five years after initial evaluation, the patients were submitted to clinical and laboratory (serum IGF-1) reassessment. Patients with persistently elevated IGF-1 were submitted to a new GH suppression test and magnetic resonance imaging (MRI) of the pituitary. Results Four patients were lost to follow-up. During reassessment, 42 patients continued to show no “typical phenotype” or changes in physiognomy. Fifteen of the 42 patients had normal IGF-1. Among the 27 patients with persistently elevated IGF-1 and who were submitted to a new OGTT, GH suppression was confirmed in all. Two patients exhibited a lesion suggestive of microadenoma on pituitary MRI. In our interpretation of the results, acromegaly was ruled out in 40 patients and considered “possible” in only 2. Conclusion Our results show that even in patients with a suggestive clinical scenario and elevated IGF-1, confirmed in a second measurement and without apparent cause, acromegaly is very unlikely in the case of GH suppression in the OGTT.

Low serum Insulin Like Growth Factor - 1 in patients with Stress Urinary Incontinence

ABSTRACT Objective: SUI, involuntary loss of urine, occurs when intra abdominal pressure exceeds urethral pressure in women. Recent animal study has shown that there are therapeutic effects of Insulin-like growth factors (IGF-1) on stress urinary incontinence in rats with simulated childbirth trauma. IGF-1 is an important mediator of cell growth, differentiation and transformation in various tissues and stimulates fibroblast proliferation and enhances collagen synthesis. The purpose of the current study was to determine the association between IGF-1 levels and SUI. Materials and Methods: All patients were evaluated for SUI and divided into two groups: 116 women with SUI and 76 women without SUI. Diagnosis of SUI was based on the International Consultation on Incontinence Questionnaire-Short Form (ICIQSF). Levels of IGF-1 were measured in serum by enzyme-linked immunosorbent assay. The relationship between IGF-1 levels and SUI in patients was evaluated statisticaly. Results: The mean age of patients wiyh SUI was 49.9±8.6 and 48.7±7.8 in control group. Plasma IGF-1 levels were significantly lower in SUI than in control group (106.5±26.4 and 133.3±37.1ng/mL, respectively, P <0.001). Body mass indexes were higher in women with SUI than women without SUI. Conclusion: In this study lower serum IGF-1 levels were found to be associated with SUI. Serum IGF-1 level appears to be a specific predictor of SUI, and it may be used in early prediction of SUI in female population.

Clonidine-stimulated growth hormone concentrations (cut-off values) measured by immunochemiluminescent assay (ICMA) in children and adolescents with short stature

OBJECTIVES: To establish cut-off values for growth hormone concentrations using clonidine as a secretagogue and an immunochemiluminescent assay as the method of measurement and to analyze the response time as well as the influence of gender, nutritional status and pubertal stage. METHODS: A total of 225 tests were performed in 3 patient groups, categorized as group 1 (normal), group 2 (idiopathic short stature) and group 3 (growth hormone deficiency). Among the 199 disease-free individuals, 138 were prepubertal, and 61 were pubertal. Clonidine (0.1 mg/m2) was orally administered, and the growth hormone level was measured by immunochemiluminescent assay. The growth hormone peak and the difference between the growth hormone peak and the baseline level were then analyzed. Statistical analyses were performed using Student’s t-test or the Mann-Whitney test and Kruskal-Wallis test followed by Dunn’s post hoc test. Cut-off values were determined using a receiver operating characteristic curve. RESULTS: Group 1 and group 2 had no difference in growth hormone peak, gender, body mass index standard deviation score, or pubertal stage. Group 3 exhibited a significantly lower growth hormone peak than the other groups did. The receiver operating characteristic curve demonstrated that growth hormone concentrations ≥ 3.0 ng/mL defined responsiveness to clonidine. In total, 3.02% of individuals in group 1 and group 2 were considered false positive, i.e., these children lacked growth hormone deficiency and had a peak below 3.0 ng/mL. CONCLUSION: Clonidine-stimulated growth hormone concentrations ≥3 ng/mL, as measured by immunochemiluminescent assay, suggest responsiveness to the stimulus regardless of gender, body mass index standard deviation score or pubertal stage.

Short hairpin RNA targeting insulin-like growth factor binding protein-3 restores the bioavailability of insulin-like growth factor-1 in diabetic rats

ABSTRACT Purpose To investigate whether intracavernosal injection of short hairpin RNA for IGFBP-3 could improve erectile function in streptozotocin-induced diabetic rats. Materials and methods After 12 weeks of IGFBP-3 short hairpin RNA injection treatment, intracavernous pressure responses to electrical stimulation of cavernous nerves were evaluated. The expression of IGFBP-3 and IGF-1 at mRNA and protein levels were detected by quantitative real-time PCR analysis and Western blot, respectively. The concentration of cavernous cyclic guanosine monophosphate was detected by enzyme-linked immunosorbent assay. Results At 12 weeks after intracavernous administration of IGFBP-3 shRNA, the cavernosal pressure was significantly increased in response to the cavernous nerves stimulation compared to the diabetic group (P<0.05). Cavernous IGFBP-3 expression at both mRNA and protein levels was significantly inhibited. At the same time, cavernous IGF-1 expression was significantly increased in the IGFBP-3 shRNA treatment group compared to the diabetic group (P<0.01). Cavernous cyclic guanosine monophosphate concentration was significantly increased in the IGFBP-3 shRNA treatment group compared to the diabetic group (P<0.01). Conclusions Gene transfer of IGFBP-3 shRNA could improve erectile function via the restoration of cavernous IGF-1 bioavailability and an increase of cavernous cGMP concentration in the pathogenesis of erectile dysfunction in streptozotocin-induced diabetic rats.