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Astrocytes play key roles in the brain. When astrocyte support fails, neurological disorders follow, resulting in disrupted synaptic communication, neuronal degeneration, and cell death. We posit that astrocytes overexpressing neurotrophic factors, such as Insulin Like Growth Factor 1 (IGF1), prevent the onset of neurodegeneration. We overexpressed IGF1 and the reporter TdTomato (TOM) in hippocampal astrocytes with bicistronic Adeno-Associated Virus (AAV) harboring the Glial Fibrillary Acidic Protein (GFAP) promoter and afterwards induced neurodegeneration by the intracerebroventricular (ICV) injection of streptozotocin (STZ), a rat model of behavioral impairment, neuroinflammation and shortening of hippocampal astrocytes. We achieved a thorough transgene expression along the hippocampus with a single viral injection. Although species typical behavior was impaired, memory deficit was prevented by IGF1. STZ prompted astrocyte shortening, albeit the length of these cells in animals injected with GFP and IGF1 vectors did not statistically differ from the other groups. In STZ control animals, hippocampal microglial reactive cells increased dramatically, but this was alleviated in IGF1 rats. We conclude that overexpression of IGF1 in astrocytes prevents neurodegeneration onset. Hence, individuals with early neurotrophic exhaustion would be vulnerable to age-related neurodegeneration.
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Astrócitos , Dependovirus , Hipocampo , Fator de Crescimento Insulin-Like I , Animais , Astrócitos/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Fator de Crescimento Insulin-Like I/genética , Hipocampo/metabolismo , Dependovirus/genética , Ratos , Masculino , Ratos Wistar , Proteína Glial Fibrilar Ácida/metabolismoRESUMO
CONTEXT: Paltusotine is a nonpeptide selective somatostatin receptor 2 agonist in development as once-daily oral treatment for acromegaly. OBJECTIVE: To evaluate the efficacy and safety of paltusotine in the treatment of patients with acromegaly previously controlled with injected somatostatin receptor ligands (SRLs). METHODS: This phase 3, randomized, double-blind, placebo-controlled trial enrolled adults with acromegaly who had insulin-like growth factor I (IGF-I) ≤1.0 times the upper limit of normal (×ULN) while receiving a stable dose of depot octreotide or lanreotide. Patients were switched from injected SRLs and randomized to receive paltusotine or placebo orally for 36 weeks. The primary endpoint was proportion of patients maintaining IGF-I ≤1.0×ULN. Secondary endpoints were change in IGF-I level, change in Acromegaly Symptom Diary (ASD) score, and maintenance of mean 5-sample growth hormone (GH) <1.0 ng/mL. RESULTS: The primary endpoint was met: 83.3% (25/30) of patients receiving paltusotine and 3.6% (1/28) receiving placebo maintained IGF-I ≤1.0×ULN (odds ratio: 126.53; 95% CI: 13.73, >999.99; P<.0001). Paltusotine was also superior to placebo for all secondary endpoints: mean (±SE) change in IGF-I of 0.04±0.09×ULN versus 0.83±0.1×ULN (P<.0001); mean (±SE) change in ASD score of -0.6±1.5 versus 4.6±1.6 (P=.02); mean GH maintained at <1.0 ng/mL in 20/23 (87.0%) versus 5/18 (27.8%) patients (odds ratio: 16.61; 95% CI: 2.86, 181.36; P=.0003). The most common adverse events were acromegaly symptoms and gastrointestinal effects characteristic of SRLs. CONCLUSION: Replacement of injected SRLs by once-daily oral paltusotine was effective in maintaining both biochemical and symptom control in patients with acromegaly and was well tolerated.
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Cancer stem cells (CSCs) are a group of tumor cells with high tumorigenic ability and self-renewal potential similar to those of normal stem cells. CSCs are the key "seeds" for tumor development, metastasis, and recurrence. A better insight into the key mechanisms underlying CSC survival improves the efficiency of cancer therapy via specific targeting of CSCs. Insulin-like growth factor (IGF)/IGF-1 receptor (IGF-1R) signaling plays an important role in the maintenance of cancer stemness. However, the effect of IGF/IGF-1R signaling on stemness and CSCs and the underlying mechanisms are still controversial. Based on the similarity between CSCs and normal stem cells, this review discusses emerging data on the functions of IGF/IGF-1R signaling in normal stem cells and CSCs and dissects the underlying mechanisms by which IGF/IGF-1R signaling is involved in CSCs. On the other hand, this review highlighted the role of IGF/IGF-1R signaling blockade in multiple CSCs as a potential strategy to improve CSC-based therapy.
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PURPOSE: The insulin-like growth factor (IGF) system includes IGF-I, IGF-II insulin and their membrane receptors. IGF system also includes a family of proteins namely insulin-like growth factor-binding proteins (IGFBPs) composed for six major members (IGFBP-1 to IGFBP6), which capture, transport and prolonging half-life of IGFs. However, it has been described that IGFBPs can also have other functions. METHODS: IGFBP5 expression was inhibited by shRNAs, migration was analyzed by scratch-wound assays, invasion assays were performed by the Boyden chamber method, spheroids formation assays were performed on ultra-low attachment surfaces, expression and phosphorylation of proteins were analyzed by Western blot. RESULTS: IGFBP5 is a repressor of IGF-IR expression, but it is not a repressor of IR in MCF-7 breast cancer cells. In addition, IGFBP5 is a suppressor of migration and MMP-9 secretion induced by IGF-I and insulin, but it does not regulate invasion in MCF-7 cells. IGFBP5 also is a repressor of MCF-7 spheroids formation. However treatment with 340 nM rescues the inhibitory effect of IGFBP in the MCF-7 spheroids formation. CONCLUSION: IGFBP5 regulates IGF-IR expression, migration and MMP-9 secretion induced by IGF-I and/or insulin, and the spheroids formation in MCF-7 breast cancer cells.
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A 46-year-old woman was troubled by a 3-year history of constant headaches and arthralgias. She was treated with paracetamol with no symptom resolution. An abnormal fasting glucose level prompted endocrine evaluation. On physical examination, she casually mentioned that her wedding ring no longer fit, and she also confirmed an increase in shoe size. There were no characteristic facial features for acromegaly and there was no evidence of acral enlargement. Biochemical evaluation, including insulin-like growth factor type 1 (IGF-1) measurement and oral glucose loading with growth hormone (GH) measurement confirmed excess GH production and a diagnosis of acromegaly. Pituitary magnetic resonance imaging showed a central pituitary microadenoma. After transsphenoidal surgical resection, tissue immunohistochemistry revealed a densely granulated somatotroph adenoma. Currently, the patient is asymptomatic with biochemical disease control, normal fasting glucose levels, and no pituitary hormone deficiencies. This patient is illustrative of a type 1 acromegaly with mild clinical manifestations. Clinicians should be aware of acromegaly subtypes to avoid delay in diagnosis and to individualize therapy.
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The study aimed to assess the effect of long-acting bST treatment, in a dose that only increases IGF-I plasma concentrations, on ovarian and fertility markers of estrous synchronized ewes that were fed to keep their bodyweight. Three experiments were designed to evaluate this effect: in Experiment 1, 18 ewes were distributed in groups (bST 0, 30, 50 mg) to measure plasma IGF-I and insulin for 15 days; in Experiment 2, 92 ewes (5 replicates) in two groups (0 and 30 mg bST) were synchronized using a 6-day progesterone protocol during the breeding season to assess the effect of bST on follicular and luteal performances, estrous and ovulation, and fertility after mating. In Experiment 3, 50 ewes (3 replicates) were used to repeat the study before but during anestrus. Results indicate that 50 mg bST increased IGF-I and insulin plasma concentrations, but 30 mg bST only increased IGF-I concentrations; and that only during the breeding season did 30 mg bST increase the number of lambs born and the reproductive success of ovulatory-sized follicles compared to controls. This occurred without it affecting any other reproductive marker. In conclusion, 30 mg bST treatment may improve oocyte competence for fertility during the breeding season.
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BACKGROUND: Human subjects with generalized growth hormone (GH) insensitivity due to GH receptor deficiency (GHRD)/Laron syndrome display a very low incidence of insulin resistance, diabetes, and cancer, as well as delayed age-related cognitive decline. However, the risk of cardiovascular disease (CVD) in these subjects is poorly understood. Here, we have assessed cardiovascular function, damage, and risk factors in GHRD subjects and their relatives. METHODS: We measured markers of CVD in two phases: one in a cohort of 30 individuals (GHRD = 16, control relatives = 14) brought to USC (in Los Angeles, CA) and one in a cohort including additional individuals examined in Ecuador (where the subjects live) for a total of 44 individuals (GHRD = 21, control relatives = 23). Data were collected on GHRD and control groups living in similar geographical locations and sharing comparable environmental and socio-economic circumstances. RESULTS: Compared to controls, GHRD subjects displayed lower serum glucose, insulin, blood pressure, smaller cardiac dimensions, similar pulse wave velocity, lower carotid artery intima-media thickness, lower creatinine, and a non-significant but major reduction in the portion of subjects with carotid atherosclerotic plaques (7% GHRDs vs. 36%, Controls p = 0.1333) despite elevated low-density lipoprotein cholesterol levels. CONCLUSION: The current study indicates that individuals with GHRD have normal or improved levels of cardiovascular disease risk factors as compared to their relatives. FUNDING: This study was funded in part by NIH/NIA grant P01 AG034906 to V.D.L.
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Doenças Cardiovasculares , Fatores de Risco de Doenças Cardíacas , Síndrome de Laron , Humanos , Masculino , Feminino , Adulto , Doenças Cardiovasculares/epidemiologia , Síndrome de Laron/genética , Pessoa de Meia-Idade , Fator de Crescimento Insulin-Like I/metabolismo , Fator de Crescimento Insulin-Like I/análise , Fator de Crescimento Insulin-Like I/deficiência , Espessura Intima-Media Carotídea , Equador/epidemiologia , Receptores da Somatotropina/genética , Receptores da Somatotropina/deficiência , Análise de Onda de Pulso , Fatores de Risco , Glicemia/metabolismo , Glicemia/análise , Pressão Sanguínea , Estudos de Casos e ControlesRESUMO
Multiple myeloma (MM) is a prevalent hematological malignancy with high recurrence and no definitive cure. The current study revisits the role of the IGF1/IGF1R axis in MM, introducing a novel inhibitor, NT157. The IGF1/IGF1R pathway is pivotal in MM, influencing cell survival, proliferation, and migration and impacting patient survival outcomes. NT157 targets intracellular proteins such as IRS and STAT proteins and demonstrates antineoplastic potential in hematological malignancies and solid tumors. In the present study, we assessed IGF1R signaling-related gene expression in MM patients and healthy donors, unveiling significant distinctions. MM cell lines displayed varying expression patterns of IGF1R-related proteins. A gene dependence analysis indicated the importance of targeting receptor and intracellular elements over autocrine IGF1. NT157 exhibited inhibitory effects on MM cell viability, clonal growth, cell cycle progression, and survival. Moreover, NT157 reduced IRS2 expression and STAT3, STAT5, and RPS6 activation and modulated oncogenes and tumor suppressors, fostering a tumor-suppressive molecular profile. In summary, our study demonstrates that the IGF1/IGF1R/IRS signaling axis is differentially activated in MM cells and the NT157's capacity to modulate crucial molecular targets, promoting antiproliferative effects and apoptosis in MM cells. NT157 may offer a multifaceted approach to enhance MM therapy.
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OBJECTIVE: To assess the impact and potential mechanistic pathways of prenatal alcohol exposure (PAE) on longitudinal growth and nutritional status in early childhood. STUDY DESIGN: A cohort of 296 mother-infant dyads (32% with PAE vs 68% unexposed) were recruited in Leyte, the Philippines, and followed from early gestation through 24 months of age. PAE was assessed using serum phosphatidylethanol (PEth) captured twice prenatally and in cord blood and supplemented with self-reported alcohol consumption. Linear mixed models were used to examine longitudinal effects of PAE on growth from birth through 2 years including key potential mediating factors (placental histopathology, and infant serum leptin and Insulin-like Growth Factor 1 [IGF-1]). RESULTS: After adjusting for potential confounders, we found that PAE was significantly associated with a delayed blunting of linear growth trajectories (height-for-age z-score, body length) and weight (weight-for-age z-score, body weight) that manifested between 4 and 6 months and continued through 12-24 months. PAE was also associated with a decreased rate of mid-upper-arm circumference growth from birth to 12 months, and a lower mean IGF-1 levels at birth and 6 months. CONCLUSION: This study demonstrates a delayed impact of PAE on growth that manifested around 6 months of age, underscoring the importance of routine clinical monitoring in early childhood. Furthermore, the findings supported prior animal model findings that suggest a mechanistic role for IGF-1 in PAE-induced growth delay.
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Fator de Crescimento Insulin-Like I , Estado Nutricional , Efeitos Tardios da Exposição Pré-Natal , Humanos , Fator de Crescimento Insulin-Like I/metabolismo , Fator de Crescimento Insulin-Like I/análise , Feminino , Filipinas/epidemiologia , Gravidez , Lactente , Masculino , Recém-Nascido , Estudos Longitudinais , Pré-Escolar , Consumo de Bebidas Alcoólicas/efeitos adversos , Desenvolvimento Infantil/efeitos dos fármacos , Adulto , Sangue Fetal/metabolismo , Sangue Fetal/química , Glicerofosfolipídeos/sangue , Peptídeos Semelhantes à InsulinaRESUMO
The role of growth hormone (GH) in the central nervous system (CNS) involves neuroprotection, neuroregeneration, formation of axonal projections, control of cognition, and regulation of metabolism. As GH induces insulin-like growth factor-1 (IGF-1) expression in many tissues, differentiating the specific functions of GH and IGF-1 in the organism is a significant challenge. The actions of GH and IGF-1 in neurons have been more extensively studied than their functions in nonneuronal cells (e.g., microglial cells). Glial cells are fundamentally important to CNS function. Microglia, astrocytes, oligodendrocytes, and tanycytes are essential to the survival, differentiation, and proliferation of neurons. As the interaction of the GH/IGF-1 axis with glial cells merits further exploration, our objective for this review was to summarize and discuss the available literature regarding the genuine effects of GH on glial cells, seeking to differentiate them from the role played by IGF-1 action whenever possible.