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Liao R, Yan F, Zeng Z, Wang H, Qiu K, Xu J, Zheng W. Insulin-like growth factor-1 activates PI3K/Akt signalling to protect human retinal pigment epithelial cells from amiodarone-induced oxidative injury. Br J Pharmacol 2017; 175:125-139. [PMID: 29057462 DOI: 10.1111/bph.14078] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 10/11/2017] [Accepted: 10/13/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND AND PURPOSE Amiodarone is one of the most effective anti-arrhythmic drugs available, but its clinical applications are limited by toxic side effects including optic toxicity. The purpose of this study was to investigate the toxic effect of amiodarone on D407 cells (a human retinal pigmented epithelial (RPE) cell line) and the mechanisms of the protective effect of insulin-like growth factor-1 (IGF-1). EXPERIMENTAL APPROACH The involvement of the kinases, Akt and ERK, was analysed by Western blot. Intracellular accumulation of ROS was measured using fluorophotometric quantification. A pharmacological approach with inhibitors was used to investigate the pathways involved in the protective action of IGF-1. KEY RESULTS Amiodarone concentration-dependently augmented the production of ROS, lipid peroxidation and apoptosis in D407 cells. IGF-1 time- and concentration-dependently reversed these effects of amiodarone and protected D407 cells from amiodarone-mediated toxicity. Amiodarone inhibited the pAkt but not pErk, and IGF-1 reversed this inhibitory effect of amiodarone. However, IGF-1 failed to suppress amiodarone-induced cytotoxicity in the presence of PI3K/Akt inhibitor LY294002 suggesting the direct involvement of the PI3K/Akt pathway. Furthermore, in vivo rat flash electroretinogram (FERG) recordings showed that IGF-1 reverses the amiodarone-induced decrease in a- and b-waves. The immunocytochemistry findings confirmed that vitreous IGF-1 injections promote the survival of RPE cells in rat retina treated with amiodarone. CONCLUSION AND IMPLICATIONS IGF-1 can protect RPE cells from amiodarone-mediated injury via the PI3K/Akt pathway in vivo and in vitro. IGF-1 has potential as a protective drug for the prevention and treatment of amiodarone-induced optic toxicity.
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Affiliation(s)
- Rifang Liao
- Faculty of Health Sciences, University of Macau, Taipa, Macau, and UM Zhuhai Research Institute, Zhuhai, China.,Department of Pharmacy, Sun Yat-Sen Memorial Hospital and the School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Fengxia Yan
- Faculty of Health Sciences, University of Macau, Taipa, Macau, and UM Zhuhai Research Institute, Zhuhai, China.,Department of Pharmacy, Sun Yat-Sen Memorial Hospital and the School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Zhuanping Zeng
- School of Public Health, Guangdong Pharmaceutical University, Guangzhou, China
| | - Haitao Wang
- Faculty of Health Sciences, University of Macau, Taipa, Macau, and UM Zhuhai Research Institute, Zhuhai, China.,School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Kaifeng Qiu
- Department of Pharmacy, Sun Yat-Sen Memorial Hospital and the School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jinying Xu
- Faculty of Health Sciences, University of Macau, Taipa, Macau, and UM Zhuhai Research Institute, Zhuhai, China
| | - Wenhua Zheng
- Faculty of Health Sciences, University of Macau, Taipa, Macau, and UM Zhuhai Research Institute, Zhuhai, China.,Department of Pharmacy, Sun Yat-Sen Memorial Hospital and the School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
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2
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Mallol C, Casana E, Jimenez V, Casellas A, Haurigot V, Jambrina C, Sacristan V, Morró M, Agudo J, Vilà L, Bosch F. AAV-mediated pancreatic overexpression of Igf1 counteracts progression to autoimmune diabetes in mice. Mol Metab 2017; 6:664-680. [PMID: 28702323 PMCID: PMC5485311 DOI: 10.1016/j.molmet.2017.05.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/09/2017] [Accepted: 05/12/2017] [Indexed: 12/31/2022] Open
Abstract
Objective Type 1 diabetes is characterized by autoimmune destruction of β-cells leading to severe insulin deficiency. Although many improvements have been made in recent years, exogenous insulin therapy is still imperfect; new therapeutic approaches, focusing on preserving/expanding β-cell mass and/or blocking the autoimmune process that destroys islets, should be developed. The main objective of this work was to test in non-obese diabetic (NOD) mice, which spontaneously develop autoimmune diabetes, the effects of local expression of Insulin-like growth factor 1 (IGF1), a potent mitogenic and pro-survival factor for β-cells with immunomodulatory properties. Methods Transgenic NOD mice overexpressing IGF1 specifically in β-cells (NOD-IGF1) were generated and phenotyped. In addition, miRT-containing, IGF1-encoding adeno-associated viruses (AAV) of serotype 8 (AAV8-IGF1-dmiRT) were produced and administered to 4- or 11-week-old non-transgenic NOD females through intraductal delivery. Several histological, immunological, and metabolic parameters were measured to monitor disease over a period of 28–30 weeks. Results In transgenic mice, local IGF1 expression led to long-term suppression of diabetes onset and robust protection of β-cell mass from the autoimmune insult. AAV-mediated pancreatic-specific overexpression of IGF1 in adult animals also dramatically reduced diabetes incidence, both when vectors were delivered before pathology onset or once insulitis was established. Transgenic NOD-IGF1 and AAV8-IGF1-dmiRT-treated NOD animals had much less islet infiltration than controls, preserved β-cell mass, and normal insulinemia. Transgenic and AAV-treated islets showed less expression of antigen-presenting molecules, inflammatory cytokines, and chemokines important for tissue-specific homing of effector T cells, suggesting IGF1 modulated islet autoimmunity in NOD mice. Conclusions Local expression of Igf1 by AAV-mediated gene transfer counteracts progression to diabetes in NOD mice. This study suggests a therapeutic strategy for autoimmune diabetes in humans. Local pancreatic IGF1 expression prevents spontaneous autoimmune diabetes. Protection achieved after one-time local administration of IGF1-encoding AAV vectors. Efficacious in animals treated early or once autoimmunity is already established. Protection through maintenance of β-cell mass and endogenous insulin secretion. Treatment leads to reduced infiltration and expression of immunity genes in islets.
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Affiliation(s)
- Cristina Mallol
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Spain.,Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.,CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08017 Madrid, Spain
| | - Estefania Casana
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Spain.,Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Veronica Jimenez
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Spain.,Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.,CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08017 Madrid, Spain
| | - Alba Casellas
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Spain.,Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.,CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08017 Madrid, Spain
| | - Virginia Haurigot
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Spain.,Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.,CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08017 Madrid, Spain
| | - Claudia Jambrina
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Spain.,Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Victor Sacristan
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Spain.,Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Meritxell Morró
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Spain.,Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.,CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08017 Madrid, Spain
| | - Judith Agudo
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Spain.,Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.,CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08017 Madrid, Spain
| | - Laia Vilà
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Spain.,Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.,CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08017 Madrid, Spain
| | - Fatima Bosch
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Spain.,Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.,CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08017 Madrid, Spain
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Xiong X, Li Q, Cui W, Gao ZH, Liu JL. Deteriorated high-fat diet-induced diabetes caused by pancreatic β-cell-specific overexpression of Reg3β gene in mice. Endocrine 2016; 54:360-370. [PMID: 27259509 DOI: 10.1007/s12020-016-0998-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 05/23/2016] [Indexed: 12/18/2022]
Abstract
Reg family proteins have long been implicated in islet β-cell proliferation, survival, and regeneration. In our previous study, we reported that Reg3β overexpression did not increase islet growth but prevented streptozotocin-induced islet damage by inducing specific genes. In order to explore its role in type 2 diabetes (T2D), we established high-fat diet (HFD)-induced obesity and diabetes in RIP-I/Reg3β mice. Glucose and insulin tolerance tests, immunofluorescence for insulin, eIF2α, and GLUT2 in islets, Western blots on phosphorylated AMPKα and hepatic histology were performed. Both RIP-I/Reg3β and wild-type mice gained weight rapidly and became hyperglycemic after 10 weeks on the HFD. However, the transgenic mice exhibited more significant acceleration in blood glucose levels, further deterioration of glucose intolerance and insulin resistance, and a lower intensity of insulin staining. Immunofluorescence revealed similar magnitude of islet compensation to a wild-type HFD. The normal GLUT2 distribution in the transgenic β-cells was disrupted and the staining was obviously diminished on the cell membrane. HFD feeding also caused a further decrease in the level of AMPKα phosphorylation in the transgenic islets. Our results suggest that unlike its protective effect against T1D, overexpressed Reg3β was unable to protect the β-cells against HFD-induced damage.
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Affiliation(s)
- Xiaoquan Xiong
- Fraser Laboratories for Diabetes Research, Department of Medicine, RI-McGill University Health Centre, Room E02.7220, 1001 Décarie Blvd, Montreal, QC, H4A 3J1, Canada
| | - Qing Li
- Fraser Laboratories for Diabetes Research, Department of Medicine, RI-McGill University Health Centre, Room E02.7220, 1001 Décarie Blvd, Montreal, QC, H4A 3J1, Canada
| | - Wei Cui
- Department of Endocrinology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Zu-Hua Gao
- Department of Pathology, RI-McGill University Health Centre, Room E04.1820, 1001 Decarie Boulevard, Montreal, QC, H4A 3J1, Canada.
| | - Jun-Li Liu
- Fraser Laboratories for Diabetes Research, Department of Medicine, RI-McGill University Health Centre, Room E02.7220, 1001 Décarie Blvd, Montreal, QC, H4A 3J1, Canada.
- Montreal Diabetes Research Centre, Montreal, Canada.
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4
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Abstract
Managing severe insulin resistance (IR) in patients with type 1 diabetes (T1DM) can be challenging for both clinicians and patients. As average weight for patients with T1DM has increased in recent decades, IR in this population has become more widespread. Currently, almost 50 % of patients with T1DM are overweight or obese. While intensive insulin therapy is associated with reduction in complications, aggressive treatment can lead to weight gain. With increasing weight, insulin can become less effective to control glycemia, resulting in higher insulin doses and hence more weight gain. Novel strategies to break this vicious cycle are needed. This review will investigate current research on insulin formulations, lifestyle modification, adjunct therapies, and surgery that may help better manage patients with T1DM and IR.
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Desai NA, Patel SS. Increased insulin-like growth factor-1 in relation to cardiovascular function in polycystic ovary syndrome: friend or foe? Gynecol Endocrinol 2015; 31:801-7. [PMID: 26288196 DOI: 10.3109/09513590.2015.1075497] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The incidence of cardiovascular disease (CVD) in patients with polycystic ovary syndrome (PCOS) is very high and conventional risk factors only partially explain excessive risk of developing CVD in patients of PCOS. The pathophysiology of PCOS is very unique, and several hormonal and metabolic changes occur. Several observations suggest that serum IGF-1 levels decrease in insulin resistance, which results in IGF-1 deficiency. In patient of PCOS, close relationships have been demonstrated between insulin resistance and serum IGF-1 levels. Hyperinsulinemic insulin resistance results in a general augmentation of steroidogenesis and LH release in PCOS. The action of IGF-1 varies in different tissues possibly via autocrine or paracrine mechanisms. The increase or decrease in IGF-1 in different tissues results in differential outcomes. Several studies suggest that lowered circulating IGF-1 levels play important role in the initiation of the cardiac hypertrophic response which results in the risk of cardiovascular disease. While recent results suggests that individual with elevated IGF-1 is protected against cardiovascular disease. Thus IGF-1 shows versatile pleiotropic actions. This review provides a current perspective on increased level of IGF-1 in PCOS and also adds to the current controversy regarding the roles of IGF-1 in cardiovascular disease.
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Affiliation(s)
- Namrata Ajaykumar Desai
- a Department of Pharmacology , Institute of Pharmacy, Nirma University , Ahmedabad , Gujarat , India
| | - Snehal S Patel
- a Department of Pharmacology , Institute of Pharmacy, Nirma University , Ahmedabad , Gujarat , India
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6
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Gunawardana SC, Piston DW. Insulin-independent reversal of type 1 diabetes in nonobese diabetic mice with brown adipose tissue transplant. Am J Physiol Endocrinol Metab 2015; 308:E1043-55. [PMID: 25898954 PMCID: PMC4469812 DOI: 10.1152/ajpendo.00570.2014] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 04/11/2015] [Indexed: 02/07/2023]
Abstract
Traditional therapies for type 1 diabetes (T1D) involve insulin replacement or islet/pancreas transplantation and have numerous limitations. Our previous work demonstrated the ability of embryonic brown adipose tissue (BAT) transplants to establish normoglycemia without insulin in chemically induced models of insulin-deficient diabetes. The current study sought to extend the technique to an autoimmune-mediated T1D model and document the underlying mechanisms. In nonobese diabetic (NOD) mice, BAT transplants result in complete reversal of T1D associated with rapid and long-lasting euglycemia. In addition, BAT transplants placed prior to the onset of diabetes on NOD mice can prevent or significantly delay the onset of diabetes. As with streptozotocin (STZ)-diabetic models, euglycemia is independent of insulin and strongly correlates with decrease of inflammation and increase of adipokines. Plasma insulin-like growth factor-I (IGF-I) is the first hormone to increase following BAT transplants. Adipose tissue of transplant recipients consistently express IGF-I compared with little or no expression in controls, and plasma IGF-I levels show a direct negative correlation with glucose, glucagon, and inflammatory cytokines. Adipogenic and anti-inflammatory properties of IGF-I may stimulate regeneration of new healthy white adipose tissue, which in turn secretes hypoglycemic adipokines that substitute for insulin. IGF-I can also directly decrease blood glucose through activating insulin receptor. These data demonstrate the potential for insulin-independent reversal of autoimmune-induced T1D with BAT transplants and implicate IGF-I as a likely mediator in the resulting equilibrium.
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Affiliation(s)
- Subhadra C Gunawardana
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - David W Piston
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
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7
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Guha N, Erotokritou-Mulligan I, Bartlett C, Nevitt SP, Francis M, Bassett EE, Cowan DA, Sönksen PH, Holt RIG. Biochemical markers of insulin-like growth factor-I misuse in athletes: the response of serum IGF-I, procollagen type III amino-terminal propeptide, and the GH-2000 score to the administration of rhIGF-I/rhIGF binding protein-3 complex. J Clin Endocrinol Metab 2014; 99:2259-68. [PMID: 24606087 DOI: 10.1210/jc.2013-3897] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT The GH-2000 and GH-2004 research groups developed a method for detecting GH misuse in athletes based on the measurement of serum IGF-I and procollagen type III amino-terminal propeptide (P-III-NP). There are reports that IGF-I is also misused by athletes, but currently there is no internationally recognized test designed to detect recombinant human IGF-I misuse. OBJECTIVE The objective of the study was to examine the response of serum IGF-I, P-III-NP, and the GH-2000 score to recombinant human (rh) IGF-I/rhIGF binding protein-3 (IGFBP-3) administration in recreational athletes. DESIGN AND SETTING This was a randomized, double-blind, placebo-controlled rhIGF-I/rhIGFBP-3 administration study at Southampton General Hospital (Southampton, United Kingdom). PARTICIPANTS Fifty-six recreational athletes (26 women, 30 men) participated in the study. INTERVENTION Participants were randomized to treatment with low-dose (30 mg/d) or high-dose (60 mg/d) rhIGF-I/rhIGFBP-3 complex or placebo for 28 days. Blood was collected throughout the drug administration and washout periods. Serum IGF-I and P-III-NP were measured using commercial immunoassays and GH-2000 scores were calculated. RESULTS IGF-I, P-III-NP, and the GH-2000 score rose in response to both low- and high-dose rhIGF-I/rhIGFBP-3 administration. The relative maximum response of IGF-I (approximately 4-fold increase in women and men) was greater than that of P-III-NP (40%-50% increase in women, 35%-50% increase in men). The GH-2000 formulae, which incorporate IGF-I and P-III-NP results, detected up to 61% of women and 80% of men in the rhIGF-I/rhIGFBP-3 groups but, using IGF-I concentrations alone, the sensitivity increased to 94% in both women and men during the administration period. CONCLUSIONS The rise in P-III-NP after rhIGF-I/rhIGFBP-3 administration is small compared with that after rhGH administration. Although rhIGF-I/rhIGFBP-3 administration can be detected using the GH-2000 score method, a test based on serum IGF-I alone provides better sensitivity.
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Affiliation(s)
- Nishan Guha
- Human Development and Health Academic Unit (N.G., I.E.-M., S.P.N., M.F., P.H.S., R.I.G.H.), Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom; Drug Control Centre (C.B., D.A.C.), Department of Forensic and Analytical Science, King's College London, London SE1 9NH, United Kingdom; and School of Mathematics, Statistics, and Actuarial Science (E.E.B.), University of Kent, Canterbury, Kent CT2 7NZ, United Kingdom
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9
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Abstract
Type 1 diabetes (T1D) is a serious disease with increasing incidence worldwide, with fatal consequences if untreated. Traditional therapies require direct or indirect insulin replacement, which involves numerous limitations and complications. While insulin is the major regulator of blood glucose, recent reports demonstrate the ability of several extra-pancreatic hormones to decrease blood glucose and improve metabolic homeostasis. Such hormones mainly include adipokines originating from adipose tissue (AT), while specific factors from the gut and liver also contribute to glucose homeostasis. Correction of T1D with adipokines is progressively becoming a realistic option, with the potential to overcome many problems associated with insulin replacement. Several recent studies demonstrate insulin-independent reversal or amelioration of T1D through administration of specific adipokines. Our recent work demonstrates the ability of healthy AT to compensate for the function of endocrine pancreas in long-term correction of T1D. This review discusses the potential of AT-related therapies for T1D as viable alternatives to insulin replacement.
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Affiliation(s)
- Subhadra C Gunawardana
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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10
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Abstract
IGF-1 (insulin-like growth factor-1) plays a unique role in the cell protection of multiple systems, where its fine-tuned signal transduction helps to preserve tissues from hypoxia, ischaemia and oxidative stress, thus mediating functional homoeostatic adjustments. In contrast, its deprivation results in apoptosis and dysfunction. Many prospective epidemiological surveys have associated low IGF-1 levels with late mortality, MI (myocardial infarction), HF (heart failure) and diabetes. Interventional studies suggest that IGF-1 has anti-atherogenic actions, owing to its multifaceted impact on cardiovascular risk factors and diseases. The metabolic ability of IGF-1 in coupling vasodilation with improved function plays a key role in these actions. The endothelial-protective, anti-platelet and anti-thrombotic activities of IGF-1 exert critical effects in preventing both vascular damage and mechanisms that lead to unstable coronary plaques and syndromes. The pro-survival and anti-inflammatory short-term properties of IGF-1 appear to reduce infarct size and improve LV (left ventricular) remodelling after MI. An immune-modulatory ability, which is able to suppress 'friendly fire' and autoreactivity, is a proposed important additional mechanism explaining the anti-thrombotic and anti-remodelling activities of IGF-1. The concern of cancer risk raised by long-term therapy with IGF-1, however, deserves further study. In the present review, we discuss the large body of published evidence and review data on rhIGF-1 (recombinant human IGF-1) administration in cardiovascular disease and diabetes, with a focus on dosage and safety issues. Perhaps the time has come for the regenerative properties of IGF-1 to be assessed as a new pharmacological tool in cardiovascular medicine.
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Thankamony GNA, Dunger DB, Acerini CL. Pegvisomant: current and potential novel therapeutic applications. Expert Opin Biol Ther 2010; 9:1553-63. [PMID: 19916734 DOI: 10.1517/14712590903449222] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Pegvisomant is a genetically engineered molecule, which exhibits specific growth hormone (GH) antagonism by directly interacting with the GH receptor. It is currently licensed for the treatment of acromegaly where surgery and medical therapy with somatostatin analogues have failed. OBJECTIVE To delineate the role of pegvisomant in the treatment of acromegaly and its novel application in other areas of clinical medicine where suppression of GH action may be of therapeutic benefit. METHODS A literature review from PubMed- and EMBASE-listed publications and the web-sites of licensing organisations for medicinal products. CONCLUSION Pegvisomant is currently used as a second line therapy in the management of acromegaly. It is highly effective in suppressing the metabolic effects of elevated GH levels when used alone or in combination with somatostatin analogues. However, its long term efficacy and safety for this indication has yet to be established. Preliminary data indicate that pegvisomant may have a role in management of type 1 diabetes with beneficial effects on insulin sensitivity and in preventing the progression of microvascular complications. Additional roles as an adjunct to cancer chemotherapy regimens and for the diagnosis of GH deficiency have been proposed, but have yet to be confirmed.
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Ohlsson C, Mohan S, Sjögren K, Tivesten A, Isgaard J, Isaksson O, Jansson JO, Svensson J. The role of liver-derived insulin-like growth factor-I. Endocr Rev 2009; 30:494-535. [PMID: 19589948 PMCID: PMC2759708 DOI: 10.1210/er.2009-0010] [Citation(s) in RCA: 295] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
IGF-I is expressed in virtually every tissue of the body, but with much higher expression in the liver than in any other tissue. Studies using mice with liver-specific IGF-I knockout have demonstrated that liver-derived IGF-I, constituting a major part of circulating IGF-I, is an important endocrine factor involved in a variety of physiological and pathological processes. Detailed studies comparing the impact of liver-derived IGF-I and local bone-derived IGF-I demonstrate that both sources of IGF-I can stimulate longitudinal bone growth. We propose here that liver-derived circulating IGF-I and local bone-derived IGF-I to some extent have overlapping growth-promoting effects and might have the capacity to replace each other (= redundancy) in the maintenance of normal longitudinal bone growth. Importantly, and in contrast to the regulation of longitudinal bone growth, locally derived IGF-I cannot replace (= lack of redundancy) liver-derived IGF-I for the regulation of a large number of other parameters including GH secretion, cortical bone mass, kidney size, prostate size, peripheral vascular resistance, spatial memory, sodium retention, insulin sensitivity, liver size, sexually dimorphic liver functions, and progression of some tumors. It is clear that a major role of liver-derived IGF-I is to regulate GH secretion and that some, but not all, of the phenotypes in the liver-specific IGF-I knockout mice are indirect, mediated via the elevated GH levels. All of the described multiple endocrine effects of liver-derived IGF-I should be considered in the development of possible novel treatment strategies aimed at increasing or reducing endocrine IGF-I activity.
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Affiliation(s)
- Claes Ohlsson
- Division of Endocrinology, Institute of Medicine, Sahlgrenska University Hospital, Göteborg, Sweden.
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13
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Abbas A, Grant PJ, Kearney MT. Role of IGF-1 in glucose regulation and cardiovascular disease. Expert Rev Cardiovasc Ther 2008; 6:1135-49. [PMID: 18793116 DOI: 10.1586/14779072.6.8.1135] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
IGF-1 is a peptide hormone that is expressed in most tissues. It shares significant structural and functional similarities with insulin, and is implicated in the pathogenesis of insulin resistance and cardiovascular disease. Recombinant human IGF-1 has been used in Type 2 diabetes to improve insulin sensitivity and aid glycemic control. There is evidence supporting IGF-1 as a vascular protective factor and it may also be beneficial in the treatment of chronic heart failure. Further understanding of the effects of IGF-1 signaling in health and disease may lead to novel approaches to the prevention and treatment of diabetes and cardiovascular disease.
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Affiliation(s)
- Afroze Abbas
- BHF Clinical Research Fellow, Division of Cardiovascular and Diabetes Research, Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Leeds, UK.
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14
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Insulin-Like Growth Factors, Cardiovascular Risk Factors, and Cardiovascular Disease. Cardiovasc Endocrinol 2008. [DOI: 10.1007/978-1-59745-141-3_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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15
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Abstract
Type 1 diabetes is recognised to include an element of insulin resistance. Insulin resistance is an independent risk factor for the development of macro- and microvascular complications of Type 1 diabetes and may also contribute to the development of the disease. This understanding comes at a time when the incidence of Type 1 diabetes appears to be rising and the public health burden from its vascular complications is high. A variety of safe and efficacious manoeuvres are available to redress insulin resistance in Type 2 diabetes. So far however, clinical trials addressing insulin resistance in Type 1 diabetes have been small with only short periods of follow-up. Regardless, these trials have yielded promising results. This review examines the evidence for insulin resistance in the pathophysiology of Type 1 diabetes and its complications, the problems associated with its measurement, and summarizes the trials aimed at reducing insulin resistance in Type 1 diabetes. This includes a meta-analysis of controlled trials of adjuvant metformin in Type 1 diabetes.
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Affiliation(s)
- T T L Pang
- Division of Medical Sciences, Medical School, University of Birmingham, Birmingham, UK
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Williams RM, McDonald A, O'Savage M, Dunger DB. Mecasermin rinfabate: rhIGF-I/rhIGFBP-3 complex: iPLEX. Expert Opin Drug Metab Toxicol 2008; 4:311-24. [PMID: 18363546 DOI: 10.1517/17425255.4.3.311] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Mecasermin rinfabate (iPLEX), comprising rhIGF-I complexed to rhIGFBP-3, was developed in an attempt to prolong the half-life of IGF-I and potentially reduce side effects. It is administered as a once-daily subcutaneous injection. Treatment with rhIGF-I has been explored in a number of growth and endocrine disorders. OBJECTIVE To review the published literature regarding the pharmacokinetics, safety profile and clinical efficacy of Mecasermin rinfabate. METHODS A comprehensive search via the NCBI PubMed portal was performed using the search terms rhIGF-I/rhIGFBP-3 complex, iPLEX and Somatokine. RESULTS The effects of Mecasermin rinfabate have been explored in a number of clinical situations including diabetes, severe insulin resistance, osteopaenia, burns and growth hormone insensitivity syndrome, with outcomes similar to those of rhIGF-I alone. CONCLUSIONS The biological effects of Mecasermin rinfabate are largely similar to those previously reported with rhIGF-I. There are little published data pertaining to pharmacokinetic properties in human subjects, and the side effect profile appears similar to that of rhIGF-I alone.
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Affiliation(s)
- Rachel M Williams
- University of Cambridge, Department of Paediatrics, Addenbrookes Hospital, Box 116, Hills Road, Cambridge CB2 2QQ, UK
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Robertson K, Lu Y, De Jesus K, Li B, Su Q, Lund PK, Liu JL. A general and islet cell-enriched overexpression of IGF-I results in normal islet cell growth, hypoglycemia, and significant resistance to experimental diabetes. Am J Physiol Endocrinol Metab 2008; 294:E928-38. [PMID: 18270301 DOI: 10.1152/ajpendo.00606.2007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Insulin-like growth factor I (IGF-I) is normally produced from hepatocytes and various other cells and tissues, including the pancreas, and is known to stimulate islet cell replication in vitro, prevent Fas-mediated beta-cell destruction and delay the onset of diabetes in nonobese diabetic mice. Recently, however, the notion that IGF-I stimulates islet cell growth has been challenged by the results of IGF-I and receptor gene targeting. To test the effects of a general, more profound increase in circulating IGF-I on islet cell growth and glucose homeostasis, we have characterized MT-IGF mice, which overexpress the IGF-I gene under the metallothionein I promoter. In early reports, a 1.5-fold-elevated serum IGF-I level caused accelerated somatic growth and pancreatic enlargement. We demonstrated that the transgene expression, although widespread, was highly concentrated in the beta-cells of the pancreatic islets. Yet, islet cell percent and pancreatic morphology were unaffected. IGF-I overexpression resulted in significant hypoglycemia, hypoinsulinemia, and improved glucose tolerance but normal insulin secretion and sensitivity. Pyruvate tolerance test indicated significantly suppressed hepatic gluconeogenesis, which might explain the severe hypoglycemia after fasting. Finally, due to a partial prevention of beta-cell death against onset of diabetes and/or the insulin-like effects of IGF-I overexpression, MT-IGF mice (which overexpress the IGF-I gene under the metallothionein I promoter) were significantly resistant to streptozotocin-induced diabetes, with diminished hyperglycemia and prevention of weight loss and death. Although IGF-I might not promote islet cell growth, its overexpression is clearly antidiabetic by improving islet cell survival and/or providing insulin-like effects.
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Affiliation(s)
- Katie Robertson
- Fraser Laboratories for Diabetes Research, Department of Medicine, McGill University Health Centre, Montreal, Quebec, Canada
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Ezzat VA, Duncan ER, Wheatcroft SB, Kearney MT. The role of IGF-I and its binding proteins in the development of type 2 diabetes and cardiovascular disease. Diabetes Obes Metab 2008; 10:198-211. [PMID: 18269635 DOI: 10.1111/j.1463-1326.2007.00709.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Patients with insulin resistance and type 2 diabetes have an excessive risk of cardiovascular disease (CVD); this increased risk is not fully explained by traditional risk factors such as hypertension and dyslipidaemias. There is now compelling evidence to suggest that abnormalities of insulin-like growth factor-I (IGF-I) and one of its binding proteins, insulin-like growth factor-binding protein-1 (IGFBP-1), occur in insulin-resistant states and may be significant factors in the pathophysiology of CVD. We reviewed articles and relevant bibliographies following a systematic search of MEDLINE for English language articles between 1966 and the present, using an initial search strategy combining the MeSH terms: IGF, diabetes and CVD. Our aim was first to review the role of IGF-I in vascular homeostasis and to explore the mechanisms by which it may exert its effects. We also present an overview of the physiology of the IGF-binding proteins, and finally, we sought to summarize the evidence to date describing the changes in the insulin/IGF-I/IGFBP-1 axis that occur in type 2 diabetes and CVD; in particular, we have focused on the potential vasculoprotective effects of both IGF-I and IGFBP-1. We conclude that this system represents an interesting and novel therapeutic target in the prevention of CVD in type 2 diabetes.
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Affiliation(s)
- Vivienne A Ezzat
- Cardiovascular Division, The James Black Centre, Kings College London, Denmark Hill Campus, London, UK
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Meissner K, Distel H, Mitzdorf U. Evidence for placebo effects on physical but not on biochemical outcome parameters: a review of clinical trials. BMC Med 2007; 5:3. [PMID: 17371590 PMCID: PMC1847831 DOI: 10.1186/1741-7015-5-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Accepted: 03/19/2007] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Recent reviews on placebo effects in clinical trials suggest that objective changes following placebo treatments may not exist or, at least, have been considerably overestimated. However, the possibility that yet unidentified subsets of parameters are responsive to placebo treatments has not been taken into account. Therefore, the aim of the present study is to examine the effects of placebo treatments on objectively measured outcome parameters by specifically focusing on peripheral disease processes. METHODS An initial dataset was collected from a MEDLINE search for placebo-controlled, randomized clinical trials. Trials with stable disease conditions were identified, and the effects of placebo treatments on peripheral outcome parameters were estimated by the changes from baseline in the placebo groups. An explorative data analysis was conducted in order to identify parameter classes with differential responsiveness to placebo treatments. A subgroup meta-analysis of a second dataset was performed to test whether the preliminary classification would also apply to placebo effects derived from the comparison of placebo groups with untreated control groups. RESULTS The explorative analysis of outcome parameters and strength of placebo effects yielded a classification into responsive "physical" versus non-responsive "biochemical" parameters. In total, 50% of trials measuring physical parameters showed significant placebo effects, compared with 6% of trials measuring biochemical parameters. A subgroup meta-analysis substantiated the differential response (physical parameters: n = 14, Hedges' pooled effect size g = 0.34, 95% CI 0.22 to 0.46; biochemical parameters: n = 15, g = 0.03, 95% CI -0.04 to 0.10). The subanalysis of the second dataset supported the classification and revealed a significant improvement for physical parameters (n = 20, g = 0.22, 95% CI 0.07 to 0.36) and a deterioration for biochemical parameters (n = 6, g = -0.17, 95% CI -0.31 to -0.02). CONCLUSION The results suggest that placebo interventions can improve physical disease processes of peripheral organs more easily and effectively than biochemical processes. This differential response offers a good starting point for theoretical considerations on possible mediating mechanisms, and for future investigations in this field.
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Affiliation(s)
- Karin Meissner
- Institute of Medical Psychology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Hans Distel
- Institute of Medical Psychology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Ulla Mitzdorf
- Institute of Medical Psychology, Ludwig-Maximilians-University Munich, Munich, Germany
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Yuen KCJ, Dunger DB. Therapeutic aspects of growth hormone and insulin-like growth factor-I treatment on visceral fat and insulin sensitivity in adults. Diabetes Obes Metab 2007; 9:11-22. [PMID: 17199714 DOI: 10.1111/j.1463-1326.2006.00591.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Growth hormone (GH) is generally considered to exert anti-insulin actions, whereas insulin-like growth factor I (IGF-I) has insulin-like properties. Paradoxically, GH deficient adults and those with acromegaly are both predisposed to insulin resistance, but one cannot extrapolate from these pathological conditions to determine the normal metabolic roles of GH and IGF-I on glucose homeostasis. High doses of GH treatment have major effects on lipolysis, which plays a crucial role in promoting its anti-insulin effects, whereas IGF-I acts as an insulin sensitizer that does not exert any direct effect on lipolysis or lipogenesis. Under physiological conditions, the insulin-sensitizing effect of IGF-I is only evident after feeding when the bioavailability of circulating IGF-I is increased. In contrast, many studies in GH deficient adults have consistently shown that GH replacement improves the body composition profile although these studies differ considerably in terms of age, the presence or absence of multiple pituitary hormone deficiency, and whether GH deficiency was childhood or adult-onset. However, the improvement in body composition does not necessarily translate into improvements in insulin sensitivity presumably due to the anti-insulin effects of high doses of GH therapy. More recently, we have found that a very low dose GH therapy (0.1 mg/day) improved insulin sensitivity without affecting body composition in GH-deficient adults and in subjects with metabolic syndrome, and we postulate that these effects are mediated by its ability to increase free 'bioavailable' IGF-I without the induction of lipolysis. These results raise the possibility that this low GH dose may play a role in preventing the decline of beta-cell function and the development of type 2 diabetes in these "high risk" subjects.
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Affiliation(s)
- K C J Yuen
- Division of Endocrinology, Oregon Health and Science University, Portland, Oregon, USA.
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21
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Williams RM, Yuen K, White D, Mallard B, Dalton RN, Acerini CL, Dunger DB. Short-term suppression of elevated growth hormone concentrations following insulin-like growth factor 1 administration in young adults with type 1 diabetes does not alter glomerular filtration or albumin excretion rates. Clin Endocrinol (Oxf) 2006; 65:439-45. [PMID: 16984235 DOI: 10.1111/j.1365-2265.2006.02600.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Young adults with type 1 diabetes mellitus (T1DM) have increased glomerular filtration rate (GFR), which may mediate progressive renal disease and microalbuminuria. This may be secondary to low concentrations of insulin-like growth factor (IGF)-I and GH hypersecretion. We tested the hypothesis that restoration of circulating IGF-I concentrations in young adults with T1DM might suppress GH secretion, GFR and urinary albumin excretion. DESIGN In a randomized double blind crossover study six young adults with T1DM (three men, 19-24 years) received 7 days treatment with rhIGF-I/insulin-like growth factor binding protein (IGFBP)-3 complex (SomatoKine) 0.4 mg/kg/day and placebo. Subjects underwent overnight insulin infusion for euglycaemia, followed by determination of GFR and albumin excretion rate. RESULTS Following IGF-I/IGFBP-3 complex, overnight insulin requirements (0.15 vs placebo 0.21 mU/kg/min, P < 0.04), plasma insulin (77 vs placebo 152 pmol/l, P < 0.01) and mean overnight GH (2.6 vs placebo 4.8 mU/l, P < 0.04) fell. IGF-I (492 vs placebo 218 ng/ml, P < 0.01) and IGFBP-3 (4.5 vs placebo 3.9 microg/ml, P < 0.05) increased. GFR did not change (145.5 (23.9) ml/min/1.73 m(2) post-IGF-I/IGFBP-3 complex vs 152.2 (19.8) post placebo). Albumin excretion rate did not change 9.5 (5.5-16.6)mg/24 h pre- vs 11.5 (9.9-20.2) post-IGF-I/IGFBP-3 complex and 10.7 (8.1-21.2) pre- vs 11.5 (8.7-29.9) post placebo. Plasma creatinine levels were lower following IGF-I/IGFBP-3 complex (mean +/- SD, 56.2 +/- 16.8 micromol/l) vs placebo (61.5, 45.0, P < 0.02). CONCLUSIONS Seven days treatment with IGF-I/IGFBP-3 complex enhanced overnight insulin sensitivity and reduced GH levels, but there was no effect on glomerular hyperfiltration or albumin excretion rates.
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22
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Amin R, Dunger DB. Growth hormone hypothesis and development of diabetic nephropathy in Type 1 diabetes. Expert Rev Endocrinol Metab 2006; 1:673-684. [PMID: 30754096 DOI: 10.1586/17446651.1.5.673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In Type 1 diabetes, poor glycemic control is the key predictor for the development of microalbuminuria, an established early marker of overt nephropathy. However, the role of other pathways in the development of diabetic nephropathy may also be important. The growth hormone (GH) hypothesis suggests that the GH-insulin-like growth factor (IGF)-1 axis may play an important role in this disease process. In Type 1 diabetes, the characteristic pattern of GH hypersecretion and low circulating IGF-1 levels results from hepatic GH resistance owing to the lack of portal insulin. Clinical data indicate that high GH and low IGF-1 levels reduce insulin sensitivity and worsen glycemic control. Furthermore, despite hepatic GH resistance, GH receptors at the kidney remain intact. Experimental data show that excess GH stimulates renal GH receptors and, through paracrine IGF-1 production, results in pathophysiological changes consistent with diabetic nephropathy, namely nephromegaly, glomerular hyperfiltration and eventual proteinuria. These abnormalities are reversed by intervention to block or normalize the local effects of GH and IGF-1. Although such data in humans are limited, preliminary trials show that interventions to increase IGF-1 levels and reduce GH hypersecretion improve glycemic control and insulin sensitivity in the short term. However, their effects on early nephropathy and end points, such as the prevalence of end stage renal disease, have yet to be determined.
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Affiliation(s)
- Rakesh Amin
- a University of Cambridge, Department of Paediatrics, Cambridge, UK
| | - David B Dunger
- b University of Cambridge, Department of Paediatrics, Box 116, Level 8, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK.
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Saukkonen T, Shojaee-Moradie F, Williams RM, Amin R, Yuen KC, Watts A, Acerini CL, Umpleby AM, Dunger DB. Effects of recombinant human IGF-I/IGF-binding protein-3 complex on glucose and glycerol metabolism in type 1 diabetes. Diabetes 2006; 55:2365-70. [PMID: 16873702 DOI: 10.2337/db05-1646] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Recombinant human IGF-I (rhIGF-I) complexed with its natural binding protein IGF-binding protein (IGFBP)-3 (rhIGF-I/IGFBP-3) is a novel formulation that has been shown to improve insulin sensitivity in type 1 diabetes, yet the mechanisms are not clear. We used stable isotopes to investigate the effects of rhIGF-I/IGFBP-3 on glucose and glycerol metabolism in type 1 diabetes. Fifteen subjects (age 13-24 years; 10 males) were studied on three occasions in random order. Each study period lasted for two days, and an injection of either placebo or rhIGF-I/IGFBP-3 (0.1-0.8 mg x kg(-1) x day (-1)) was given subcutaneously at 6:00 p.m. on days 1 and 2. Following the second injection, the subjects were kept euglycemic overnight by a variable rate insulin infusion, followed by a 4-h, two-step (insulin 0.6 and 1.5 mU x kg(-1) x min (-1)) hyperinsulinemic-euglycemic clamp. During the overnight basal steady state, rhIGF-I/IGFBP-3 dose-dependently reduced endogenous glucose production rate (R(a)) (P = 0.004), while peripheral glucose uptake (R(d)) was not different from placebo. The increase in glucose R(d) during hyperinsulinemic clamp was greater following rhIGF-I/IGFBP-3 than placebo, both during the first (P = 0.008) and second step (P = 0.008) of the clamp. No significant differences were found in glycerol R(a), a measure of lipolysis, between rhIGF-I/IGFBP-3 and placebo. In conclusion, rhIGF-I/IGFBP-3 enhances glucose metabolism by controlling both endogenous glucose output and peripheral glucose uptake.
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Affiliation(s)
- Tero Saukkonen
- Department of Paediatrics, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK
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24
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Berg U, Gustafsson T, Sundberg CJ, Carlsson-Skwirut C, Hall K, Jakeman P, Bang P. Local changes in the insulin-like growth factor system in human skeletal muscle assessed by microdialysis and arterio-venous differences technique. Growth Horm IGF Res 2006; 16:217-223. [PMID: 16904923 DOI: 10.1016/j.ghir.2006.05.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Revised: 04/01/2006] [Accepted: 05/23/2006] [Indexed: 11/22/2022]
Abstract
IGF-I plays a direct role in whole body glucose homeostasis primarily by stimulating skeletal muscle glucose uptake. IGF-I is also involved in exercise induced muscle hypertrophy. Knowledge regarding local changes in muscle IGF-I bioavailability and its regulation by IGFBPs at rest and during exercise is limited. We have therefore explored changes in total IGF-I levels as well as circulating IGFBP levels and their post-translational modifications over an exercising leg. For the first time we have determined IGF-I levels in exercising skeletal muscle microdialysate in an attempt to assess local IGF-I bioavailability. Eighteen healthy young men performed one legged knee-extension exercise during 45min. Blood samples were taken from the femoral artery and vein of the exercising leg. No significant differences between arterial and venous concentrations of total IGF-I or IGFBP-1 were detected over the leg at any time. IGF-I concentrations increased significantly during exercise in the artery but not in the vein. Total IGFBP-1 increased after exercise in both artery and vein. The increase in non-plus less phosphorylated forms of IGFBP-1 was less pronounced and did not reach statistical significance. The proportion of fragmented IGFBP-3 (IGFBP-3 proteolysis) assessed by Western immunoblotting did not change significantly during or after exercise. Although optimization and validation of IGF-I determinations in muscle microdialysate (md) will be required, our first results using this technique demonstrate a significant 2-fold increase in mdIGF-I collected during and after exercise. We conclude that determination of A-V-differences appears to be of limited value in the assessments of local muscle change in the IGF-system. A substantial release of IGF-I during short time is required to detect significant change in the large circulating store of IGF-I. We suggest that an optimized and validated microdialysis technique for determination of local IGF-I may be advantageous in future studies.
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Affiliation(s)
- U Berg
- Department of Woman and Child Health, Pediatric Endocrinology Unit, Karolinska Institute, Astrid Lindgren Children's Hospital, Stockholm, Sweden.
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Seigel GM, Lupien SB, Campbell LM, Ishii DN. Systemic IGF-I treatment inhibits cell death in diabetic rat retina. J Diabetes Complications 2006; 20:196-204. [PMID: 16632241 DOI: 10.1016/j.jdiacomp.2005.06.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2004] [Revised: 01/28/2005] [Accepted: 06/20/2005] [Indexed: 10/24/2022]
Abstract
Diabetic retinopathy can result in apoptotic cell death of retinal neurons, as well as significant visual loss. It is further known that insulin-like growth factor (IGF) levels are reduced in diabetes and that IGF-I can prevent cell death in many cell types. In this study, we tested the hypothesis that systemic treatment with IGF-I could inhibit death of neuroretinal cells in diabetic rats by examining the expression of proapoptotic markers. In diabetic rat retina, the number of TUNEL-immunoreactive cells increased approximately sixfold in the photoreceptor layer (P<.001) and eightfold in the inner nuclear layer (INL; P<.001); phospho-Akt (p-Akt; Thr 308) immunoreactivity increased eightfold in the ganglion cell layer (GCL; P<.001) and threefold in the INL (P<.01). Subcutaneous IGF-I treatment significantly reduced the number of TUNEL (P<.001) and p-Akt immunoreactive retinal cells (P<.05) in diabetic rats approximately to the level of the nondiabetic group. Qualitative results showed that caspase-3 and BAD immunoreactivities were also elevated in diabetes and reduced in IGF-I-treated animals. Elevated TUNEL and p-Akt immunoreactivities were localized to distinct cell layers in the retina of diabetic rats. Early intervention with systemic IGF-I reduced the presence of proapoptotic markers indicative of neuroretinal cell death, despite ongoing hyperglycemia and weight loss. The eye is a special sensory organ, and these data show that cell loss in the nervous system, even in uncontrolled diabetes, can be prevented by IGF-I administration.
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Affiliation(s)
- Gail M Seigel
- Department of Ophthalmology, University at Buffalo, Buffalo, NY 14214, USA
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Calkin AC, Allen TJ. Diabetes mellitus-associated atherosclerosis: mechanisms involved and potential for pharmacological invention. Am J Cardiovasc Drugs 2006; 6:15-40. [PMID: 16489846 DOI: 10.2165/00129784-200606010-00003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
While diabetes mellitus is most often associated with hypertension, dyslipidemia, and obesity, these factors do not fully account for the increased burden of cardiovascular disease in patients with the disease. This strengthens the need for comprehensive studies investigating the underlying mechanisms mediating diabetic cardiovascular disease and, more specifically, diabetes-associated atherosclerosis. In addition to the recognized metabolic abnormalities associated with diabetes mellitus, upregulation of putative pathological pathways such as advanced glycation end products, the renin-angiotensin system, oxidative stress, and increased expression of growth factors and cytokines have been shown to play a causal role in atherosclerotic plaque formation and may explain the increased risk of macrovascular complications. This review discusses the methods used to assess the development of atherosclerosis in the clinic as well as addressing novel biomarkers of atherosclerosis, such as low-density lipoprotein receptor-1. Experimental models of diabetes-associated atherosclerosis are discussed, such as the streptozocin-induced diabetic apolipoprotein E knockout mouse. Results of major clinical trials with inhibitors of putative atherosclerotic pathways are presented. Other topics covered include the role of HMG-CoA reductase inhibitors and fibric acid derivatives with respect to their lipid-altering ability, as well as their emerging pleiotropic anti-atherogenic actions; the effect of inhibiting the renin-angiotensin system by either ACE inhibition or angiotensin II receptor antagonism; the effect of glycemic control and, in particular, the promising role of thiazolidinediones with respect to their direct anti-atherogenic actions; and newly emerging mediators of diabetes-associated atherosclerosis, such as advanced glycation end products, vascular endothelial growth factor and platelet-derived growth factor. Overall, this review aims to highlight the observation that various pathways, both independently and in concert, appear to contribute toward the pathology of diabetes-associated atherosclerosis. Furthermore, it reflects the need for combination therapy to combat this disease.
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Affiliation(s)
- Anna C Calkin
- JDRF Danielle Alberti Memorial Centre for Diabetes Complications, Baker Heart Research Institute, Melbourne, Victoria, Australia.
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Ferry RJ, Cohen P, Levitt Katz LE. Pharmacodynamic considerations with recombinant human insulin-like growth factor-I in children. HORMONE RESEARCH 2005; 63:220-7. [PMID: 15886488 PMCID: PMC3102299 DOI: 10.1159/000085682] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2004] [Accepted: 03/11/2005] [Indexed: 11/19/2022]
Abstract
AIM To report effects of weight-based recombinant human insulin-like growth factor-I (rhIGF-I) on IGF axis parameters in children with hyperinsulinism. METHODS Open label trial with subcutaneous rhIGF-I (40 microg/kg/dose). Patients studied were children (1 month to 11 years) with diffuse hyperinsulinism (n = 7). Serial serum IGF and insulin-like growth factor binding protein (IGFBP) concentrations were measured by RIA and analyzed by linear Pearson regression. RESULTS Following the initial rhIGF-I dose, total insulin-like growth factor-I (IGF-I) rose by 56% at 30 min (p < 0.01) and 85% at 120 min (p < 0.02). Serum IGF-II, IGFBP-2, and IGFBP-3 levels did not change. Peak serum IGF-I levels within 12 h of the initial rhIGF-I dose were 167-700 mg/ml. The variable peak IGF-I response is attributable in part to IGFBP-3 differences across this pediatric age range. Models of rhIGF-I dosing based upon body surface area (BSA) or initial IGFBP-3 resulted in predictable peak serum IGF-I levels (r = 0.78; p < 0.03). Recalculating rhIGF-I dosing based upon the BSA . IGFBP-3 product correlated closely with peak IGF-I level (r = 0.85; p < 0.007). CONCLUSIONS Weight-based IGF-I dosing in this cohort resulted in variable IGF-I levels. Considering BSA and serum IGFBP-3 concentration in children is appropriate for subcutaneous IGF-I administration. A combination of these values may yield predictable individualization of rhIGF-I dosing.
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Affiliation(s)
- Robert J. Ferry
- Division of Pediatric Endocrinology and Diabetes, Departments of Pediatrics and Cellular and Structural Biology, The University of Texas Health Science Center at San Antonio, Tex., USA; and 2nd Battalion, 112th Armored Regiment, 36th Infantry Division, Texas Army National Guard, 56th Brigade Combat Team, Iraq
| | - Pinchas Cohen
- Division of Pediatric Endocrinology, Mattel Children’s Hospital and David Geffen School of Medicine, The University of California, Los Angeles, Calif
| | - Lorraine E. Levitt Katz
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, The University of Pennsylvania, Philadelphia, Pa., USA
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Ranke MB. Insulin-like growth factor-I treatment of growth disorders, diabetes mellitus and insulin resistance. Trends Endocrinol Metab 2005; 16:190-7. [PMID: 15860416 DOI: 10.1016/j.tem.2005.03.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Insulin-like growth factor I (IGF-I) has many potential therapeutic uses because of its varied effects--growth promotion, insulin-like influence on glucose metabolism, and neuroprotection resulting from cell-proliferative and antiapoptotic properties--but they have not been investigated systematically in clinical situations. The growth-promoting effect of recombinant human IGF-I (rhIGF-I) in the extensively studied growth hormone insensitivity syndrome (GHIS; Laron syndrome) signifies an endocrine role for the GH-IGF system. The metabolism of (adult) patients with severe insulin resistance is improved by rhIGF-I, which--together with insulin therapy--also improves metabolic control in type 1 and 2 diabetes. Further studies on IGF-I metabolic effects and growing understanding of the IGF-I-IGF-binding protein system could open new therapeutic avenues.
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Affiliation(s)
- Michael B Ranke
- Paediatric Endocrinology Section, University Children's Hospital, Hoppe-Seyler-Strasse 1, D-72076 Tübingen, Germany.
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29
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Abstract
IGF-I mediates some, but not all of the metabolic actions of GH and it has both GH-like and insulin-like actions in vivo. GH and IGF-I both have a net anabolic effect in man enhancing whole body protein synthesis over a period of weeks and perhaps months. Both hormones favorably improve body composition in GH deficient subjects with an increase in lean body mass and decreased adiposity. This is also observed when IGF-I is given to patients with GH-receptor mutations. These compounds, however, have divergent effects on carbohydrate metabolism. A potent glucose lowering effect is typically observed after IGF-I administration, with improved insulin sensitivity with marked lowering of circulating insulin concentrations, whereas GH therapy is associated with mild compensatory hyperinsulinemia, a reflection of relative insulin resistance. The latter observation makes IGF-I a potentially more convenient anabolic agent to use in conditions where carbohydrate metabolism is more likely to be impaired. GH increases lipolysis as a direct effect of GH on the adipocyte, as well as lipid oxidation by increasing substrate availability. However IGF-I increases lipid oxidation only when given chronically, most likely as a result of chronic insulinopenia. These compounds have been tried in a variety of catabolic conditions in man and both hormones have been effective in reducing the protein wasting effects of glucocorticosteroids and mitigate some of the catabolic effects of severe hypogonadism in males. A comparison of these and other effects of these hormones is provided in this brief review. Subsequent studies are still needed to fully elucidate the safety and efficacy of IGF-I for use in humans.
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Affiliation(s)
- Nelly Mauras
- Division of Endocrinology, The Department of Pediatrics at the Nemours Children's Clinic, 807 Children's Way, Jacksonville, FL 32207, USA.
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Atabek ME, Kurtoglu S, Demir F, Baykara M. Relation of serum leptin and insulin-like growth factor-1 levels to intima-media thickness and functions of common carotid artery in children and adolescents with type 1 diabetes. Acta Paediatr 2004; 93:1052-7. [PMID: 15456195 DOI: 10.1111/j.1651-2227.2004.tb02717.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND AIM Leptin and insulin-like growth factor-1 (IGF-1) have been suggested to be involved in the pathogenesis of atherosclerosis. The aim of this study was to evaluate the relationship between serum leptin, IGF-1 and intima-media thickness (IMT) and functions of common carotid artery (CCA) in children and adolescent patients with type 1 diabetes. MATERIAL AND METHODS Serum leptin and IGF-1 levels were measured in 45 diabetic patients (23 girls and 22 boys). Age, diabetes duration as well as major cardiovascular risk factors, including anthropometric and metabolic parameters, were matched between girls and boys. The relation of serum leptin and IGF-1 levels to CCA structure and functions were measured by ultrasonography as IMT, cross-sectional compliance (CSC), cross-sectional distensibility (CSD), diastolic wall stress (DWS) and incremental elastic modulus (IEM). RESULTS Serum leptin levels of diabetic girls were higher than those in the boys (21.8 +/- 14.5 microg/l vs 8.9 +/- 10.6 micro/l, p = 0.002). However, the difference for serum IGF-I levels was not significant between diabetic girls and boys (240.7 +/- 96.8 ng/ml vs 234.7 +/- 93.2 ng/ml; p > 0.05). In all subjects, leptin levels were correlated with CSC (p = 0.04), CSD (p = 0.04) and IEM (p = 0.01), and IGF-1 levels were only correlated with CSC (p = 0.01). Leptin did not show any correlation with ultrasonographic measurements in both girls and boys separately. IGF-1 was correlated with CSC (p = 0.001), CSD (p = 0.002) and IEM (p < 0.001) in boys but not in girls. In a multivariate regression model, IGF-1 emerged as independent correlates for mean CSD and IEM in boys but not in girls. CONCLUSION Serum leptin and IGF-1 levels in children and adolescent patients with type 1 diabetes are associated with functions of common carotid artery, and the association of IGF-1 levels is influenced by sex.
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Affiliation(s)
- M E Atabek
- Department of Paediatrics, Selçuk University, Faculty of Medicine, Konya, Turkey.
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Abstract
The potential therapeutic applications of the insulin-like growth factors (IGFs) are broad. This review focuses on treatment of humans with recombinant human IGF-I (rhIGF-I), and with a rhIGF-I/IGF binding protein-3 (IGFBP-3) complex. Several groups of patients have been treated effectively, including individuals with growth hormone insensitivity syndrome (GHIS) secondary to GH receptor deficiency, to IGF-I gene deletion, or to defects in GH signal transduction pathways, patients with type 1 and type 2 diabetes mellitus, or individuals with severe insulin resistance syndromes. In each of these conditions rhIGF-I therapy has been demonstrated to be of clear clinical benefit. Other conditions, which may potential targets for therapy with rhIGF-I or rhIGF-I/IGFBP-3, include chronic inflammatory or nutritional disorders such as Crohn's disease, juvenile chronic arthritis, or cystic fibrosis. Therapy with IGFs has not been attempted in these disorders yet, in part because of lack of adequate supplies. Recently, the newly developed rhIGF-I/IGFBP-3 complex has been used in early clinical studies. Pharmacokinetic analyses in patients with diabetes mellitus and GHIS have suggested that a more physiological profile of serum IGF-I results. Improved glycaemic control has been reported in type 1 and type 2 diabetes in adults. A therapeutic trial in naïve children with GHIS is currently under way.
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Affiliation(s)
- Martin O Savage
- Research Centre in Clinical and Molecular Endocrinology, William Harvey Research Institute, Queen Mary's School of Medicine and Dentistry, Queen Mary's, University of London, London, UK.
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Jefferies CA, Hamilton J, Daneman D. Potential Adjunctive Therapies in Adolescents with Type 1 Diabetes Mellitus. ACTA ACUST UNITED AC 2004; 3:337-43. [PMID: 15511128 DOI: 10.2165/00024677-200403060-00002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Appropriate insulin therapy is central to the management of all individuals with type 1 diabetes mellitus. The potential role of adjunctive therapy in type 1 diabetes is to improve insulin action, and facilitate the ability of all individuals with type 1 diabetes to achieve and maintain 'better' metabolic control. The landmark clinical trial in type 1 diabetes is the Diabetes Control and Complications Trial (DCCT). The DCCT showed that there is no threshold below which a reduction in glycemia would not provide further benefit against diabetes-related microvascular complications. This study in particular provides the rationale for attempting to achieve as near normoglycemia as possible. We review the use of recognized pharmacologic agents as potential insulin adjunctives in children and adolescents with type 1 diabetes. Adjunctive therapies can be grouped into the following categories based on their putative mechanism of action: enhancement of insulin action (e.g. the biguanides and thiazolidinediones), alteration of gastrointestinal nutrient delivery (e.g. acarbose and amylin), and other targets of action (e.g. pirenzepine and insulin-like growth factor-1 [IGF-1], which reduce growth hormone secretion, and glucagon-like peptide-1, which acts to stimulate insulin secretion). Many of these agents have been found to be effective in short-term studies with decreases in glycosylated hemoglobin of 0.5-1.0%, lowered postprandial blood glucose levels, and decreased daily insulin doses. Adverse effects such as poor gastrointestinal tolerability (metformin, acarbose) or potential acceleration of retinopathy (IGF-1) indicates the need for further studies of efficacy, safety, and patient selection before these adjunctive therapies can be widely recommended in type 1 diabetes.
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Affiliation(s)
- Craig A Jefferies
- Division of Endocrinology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario M5G 1X8, Canada
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Wudy SA, Högel J, Dollinger B, Mullis P, Heinze E. Glimepiride treatment and IGF-I in adolescents with type 1 diabetes: a prospective, randomized, double-blind, placebo-controlled study. Diabetes Care 2003; 26:1312-3. [PMID: 12663616 DOI: 10.2337/diacare.26.4.1312] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Abstract
Homeostatic mechanisms normally maintain the plasma glucose concentration within narrow limits despite major fluctuations in supply and demand. There is increasing evidence that the growth hormone (GH)-insulin-like growth factor (IGF) axis may play an important role in glucose metabolism. GH has potent effects on intermediary metabolism, some of which antagonize the actions of insulin. In contrast, IGF-I has insulin-like actions, which are, in the case of glucose metabolism, opposite to those of GH. There is often deranged glucose metabolism in situations where GH is deficient or in excess. The clinical administration of GH or IGF-I results in altered glucose metabolism and changes in insulin resistance. Despite these observations, the precise role of GH and IGF-I and their interactions with insulin in controlling normal glucose homeostasis are unknown. In diabetes, GH secretion is abnormally increased as a result of reduced portal insulin resulting in impaired hepatic IGF-I generation. Evidence suggests that this may contribute to the development of diabetic microvascular complications. IGF-I 'replacement' in diabetes is under investigation and new methods of delivering IGF-I as a complex with IGFBP-3 offer exciting new prospects.
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Affiliation(s)
- R I G Holt
- Endocrinology Sub-Division, Fetal Origins of Adult Disease Division, University of Southampton, Southampton General Hospital, Southampton, UK.
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Abstract
Diabetic retinopathy is a highly specific vascular complication of both type 1 and type 2 diabetes, estimated to be the most frequent cause of new cases of blindness in the working population of the Western world. The prevalence of retinopathy is strongly related to the duration of diabetes and glycemic control, even though a multifactorial pathogenesis should be probably considered in genetically susceptible subjects. Intensive diabetes management, with the goal of achieving near-normal glycemia, has been shown to prevent and/or delay the onset of diabetic retinopathy and laser photocoagulation has an established clinical efficacy in preventing visual loss. However, as laser scars always destroy the retinal anatomy permanently, a medical approach to nonproliferative retinopathy should be preferred if its clinical efficacy could be demonstrated. In this paper, recently published reports supporting this hypothesis are reviewed and their conclusions critically discussed.
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Affiliation(s)
- C Giusti
- Free University Campus Bio-Medico, Rome, Italy.
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Ren J. Short-term administration of insulin-like growth factor I (IGF-1) does not induce myocardial IGF-1 resistance. Growth Horm IGF Res 2002; 12:162-168. [PMID: 12162997 DOI: 10.1016/s1096-6374(02)00020-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The advent of recombinant technology has revealed attractive therapeutic profile of insulin-like growth factor I (IGF-1) in the treatment of chronic cardiovascular diseases such as diabetes and heart failure. However, the safety and potential adverse effect of IGF-1 have not been well defined. This study was designed to evaluate the impact of short-term IGF-1 administration on myocardial contractile function. Adult rats were given recombinant human IGF-1 (3mg/kg/d, s.c.) for 8 weeks. Mechanical properties were evaluated in left-ventricular papillary muscles using a force-transducer. Myocardial contractile properties analyzed included peak tension development (PTD), time-to-peak tension (TPT), time-to-90% relaxation (RT(90)), and maximal velocity of tension development/decline (+/-VT). Short-term IGF-1 treatment enhanced the plasma IGF-1 level but had no effect on body and organ weights. The myocardium from IGF-1-treated rats exhibited enhanced PTD associated with similar TPT, RT(90), and +/-VT compared to the control group. IGF-1-treated myocardium exhibits an enhanced PTD-Ca(2+) response and a better intracellular Ca(2+) replenishing ability at the low stimulus frequencies. Acute application of IGF-1 (1-500 ng/ml) elicited a comparable concentration-dependent increase in PTD in myocardium from both control and the IGF-1-treated groups. Acute IGF-1 application had no effect on +/-VT, TPT, and RT(90) in either group tested. Pretreatment with the nitric oxide synthase inhibitor N omega-nitro-L-arginine methyl ester blunted the IGF-1-induced positive response in myocardium from both control and IGF-1-treated groups. These results suggest that short-term IGF-1 treatment is unlikely to induce IGF-1 resistance in myocardial contractile function.
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Affiliation(s)
- Jun Ren
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine, Grand Forks, ND 58203, USA.
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Van den Berghe G, Baxter RC, Weekers F, Wouters P, Bowers CY, Iranmanesh A, Veldhuis JD, Bouillon R. The combined administration of GH-releasing peptide-2 (GHRP-2), TRH and GnRH to men with prolonged critical illness evokes superior endocrine and metabolic effects compared to treatment with GHRP-2 alone. Clin Endocrinol (Oxf) 2002; 56:655-69. [PMID: 12030918 DOI: 10.1046/j.1365-2265.2002.01255.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Central hyposomatotrophism, hypothyroidism and hypogonadism are present concomitantly in men with prolonged critical illness. This study evaluated the impact of combined treatment with GH-releasing peptide-2 (GHRP-2), TRH and GnRH for 5 days compared with GHRP-2 + TRH and with GHRP-2 alone. PATIENTS AND DESIGN Thirty-three men with prolonged critical illness participated at baseline compared to 50 age- and body mass index (BMI)-matched controls. Patients were randomly assigned to 5 days of placebo (n = 7), GHRP-2 (1 microg/kg/h; n = 9), GHRP-2 + TRH infusion (1 + 1 microg/kg/h; n = 9) or pulsatile GnRH (0.1 microg/kg every 90 min) together with GHRP-2 + TRH infusion (n = 8). MEASUREMENTS GH, TSH and LH secretion were quantified by deconvolution analysis of serum concentration time series obtained by sampling every 20 min from 2100 to 0600 h at baseline and on nights 1 and 5 of treatment. Serum concentrations of IGF-I, IGFBPs, thyroid hormones, gonadal and adrenal steroids, proinflammatory cytokines and selected metabolic and inflammation markers were measured daily. RESULTS Patients revealed suppressed pulsatile GH, TSH and LH secretion in the face of low serum concentrations of IGF-I, IGFBP-3 and the acid-labile subunit (ALS) (P < 0.0001 each), thyroid hormones (P < 0.0001) and total and estimated free testosterone (P < 0.0001) levels, whereas free oestradiol (E2) estimates were normal. Serum dehydroepiandrosterone sulphate (DHEAS) levels were also suppressed whereas morning cortisol was normal. Serum levels of type I procollagen (PICP) and bone alkaline phosphatase (sALP) were elevated whereas osteocalcin (OC) was low (P = 0.03). Ureagenesis (P < 0.0001) and breakdown of bone tissue (P < 0.0001) were increased. Baseline serum TNF-alpha, IL-6 and C-reactive protein level and white blood cell (WBC) count were elevated; serum lactate was normal. Only low T4 and high IGFBP-1 levels independently predicted mortality. GHRP-2 infusion reactivated GH secretion and normalized serum IGF-I, IGFBP-3 and ALS. GHRP-2 + TRH infusion reactivated both the GH axis and the thyroid axis, with normal levels of T4 and T3 reached within 1 day. Only GHRP-2 + TRH infusion combined with GnRH pulses reactivated the GH and TSH axis and at the same time increased pulsatile LH secretion compared to placebo. Only GnRH pulses together with GHRP-2 + TRH infusion increased testosterone significantly from day 2 (peak increase of + 312%) through day 5 and serum E2 with > 80% from day 1 through day 3 (all P = 0.05). Ureagenesis was reduced by GHRP-2 + TRH + GnRH (P = 0.01) and by GHRP-2 + TRH (P = 0.009) but not by GHRP-2 alone. Serum OC levels were increased only by GHRP-2 + TRH + GnRH (P = 0.03), with a trend for GHRP-2 + TRH (P = 0.09), but not by GHRP-2 alone. On day 5, serum lactate levels and WBC count were increased by GHRP-2 infused alone and in combination with TRH but not by GHRP-2 + TRH + GnRH. CONCLUSIONS Coadministration of GHRP-2, TRH and GnRH reactivated the GH, TSH and LH axes in prolonged critically ill men and evoked beneficial metabolic effects which were absent with GHRP-2 infusion alone and only partially present with GHRP-2 + TRH. These data underline the importance of correcting the multiple hormonal deficits in patients with prolonged critical illness to counteract the hypercatabolic state.
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Affiliation(s)
- Greet Van den Berghe
- Department of Intensive Care Medicine, University Hospital Gasthuisberg, University of Leuven, B-3000 Leuven, Belgium.
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Christ ER, Carroll PV, Albany E, Umpleby AM, Lumb PJ, Wierzbicki AS, Sönksen PH, Russell-Jones DL. Effect of IGF-I therapy on VLDL apolipoprotein B100 metabolism in type 1 diabetes mellitus. Am J Physiol Endocrinol Metab 2002; 282:E1154-62. [PMID: 11934682 DOI: 10.1152/ajpendo.00470.2001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Abnormal lipid metabolism may be related to the increased cardiovascular risk in type 1 diabetes. Secretion and clearance rates of very low density lipoprotein (VLDL) apolipoprotein B100 (apoB) determine plasma lipid concentrations. Type 1 diabetes is characterized by increased growth hormone (GH) secretion and decreased insulin-like growth factor (IGF) I concentrations. High-dose IGF-I therapy improves the lipid profile in type 1 diabetes. This study examined the effect of low-dose (40 microg.kg(-1).day(-1)) IGF-I therapy on VLDL apoB metabolism, VLDL composition, and the GH-IGF-I axis during euglycemia in type 1 diabetes. Using a stable isotope technique, VLDL apoB kinetics were estimated before and after 1 wk of IGF-I therapy in 12 patients with type 1 diabetes in a double-blind, placebo-controlled trial. Fasting plasma triglyceride (P < 0.03), VLDL-triglyceride concentrations (P < 0.05), and the VLDL-triglyceride-to-VLDL apoB ratio (P < 0.002) significantly decreased after IGF-I therapy, whereas VLDL apoB kinetics were not significantly affected by IGF-I therapy. IGF-I therapy resulted in a significant increase in IGF-I and a significant reduction in GH concentrations. The mean overnight insulin concentrations during euglycemia decreased by 25% after IGF-I therapy. These results indicate that low-dose IGF-I therapy restores the GH-IGF-I axis in type 1 diabetes. IGF-I therapy changes fasting triglyceride concentrations and VLDL composition probably because of an increase in insulin sensitivity.
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Affiliation(s)
- Emanuel R Christ
- Department of Endocrinology and Diabetology of the Adult, University Hospital of Bern, Inselspital, CH-3010 Bern, Switzerland.
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Mohamed-Ali V, Pinkney J. Therapeutic Potential of Insulin-Like Growth Factor-1 in Patients with Diabetes Mellitus. ACTA ACUST UNITED AC 2002; 1:399-410. [PMID: 15832492 DOI: 10.2165/00024677-200201060-00005] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Insulin-like growth factor-1 (IGF-1) and its receptors share considerable homology with insulin and insulin receptors, and their respective signaling pathways interact at the post receptor level. While the growth hormone (GH)-IGF-1 axis principally regulates tissue growth and differentiation, insulin exerts it primary effects on fuel metabolism. However, these two endocrine systems interact at multiple levels and in diabetes mellitus the GH-IGF-1 axis is grossly disturbed, with increased secretion of GH, reduced plasma levels of IGF-1, and complex tissue-specific changes in IGF binding proteins (IGFBPs). These observations have given rise to the view that GH-IGF-1 axis dysfunction, particularly low plasma levels of circulating IGF-1, probably play a significant role in several aspects of the pathophysiology of diabetes mellitus, including insulin resistance and poor glycemic control, and may also influence the development of microvascular complications. The availability of recombinant human IGF-1 (rhIGF-1; mecasermin), used either alone or in combination with insulin, has led to experimental studies and clinical trials in humans testing these hypotheses. These studies have examined the impact of subcutaneous rhIGF-1 injections on sensitivity and metabolic parameters. In patients with type 1 and 2 diabetes mellitus, insulin sensitivity is significantly improved, insulin requirements are reduced, and glycemic control of dyslipidemia is generally improved in short-term studies. rhIGF-1 is a particularly attractive possibility in patients with type 2 diabetes mellitus, where insulin resistance is the fundamental problem. Some patients with genetic syndromes of severe insulin resistance also benefit from treatment with rhIGF-1, which can bypass blocks in the insulin signaling pathway. The common adverse effects reported for rhIGF-1 are dose-related and include edema, jaw pain, arthralgia, myalgia, hypotension, injection site pain, and less commonly, Bell's palsy and raised intracranial pressure. Although disturbance of the GH-IGF-1 axis participates in the development of diabetic complications, the functional consequences of the complex changes in IGFBP expression at the tissue level are uncertain, and it is not known whether systemic IGF-1 therapy or other manipulations of the GH-IGF-1 axis would be helpful or harmful. Experimentally, IGF-1 has a protective effect on neuropathy, and could find an application in the healing of neuropathic ulcers. The potential benefits of IGF-1 therapy in diabetes mellitus have yet to be realised.
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Affiliation(s)
- Vidya Mohamed-Ali
- Adipokines and Metabolism Research Group, Department of Medicine, University College London, London, UK.
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Crowne EC, Samra JS, Cheetham T, Acerini CL, Watts A, Holly JM, Dunger DB. The role of IGF-binding proteins in mediating the effects of recombinant human IGF-I on insulin requirements in type 1 diabetes mellitus. J Clin Endocrinol Metab 2001; 86:3686-91. [PMID: 11502796 DOI: 10.1210/jcem.86.8.7722] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To determine the role of IGF-binding proteins in mediating the direct effects of recombinant human IGF-I on insulin requirements in type 1(insulin-dependent) diabetes mellitus, overnight changes in IGF-I, IGF-II, and IGF-binding protein-1, -2, and -3, collected under euglycemic conditions, were compared in nine subjects after double blind, randomized, sc administration of recombinant human IGF-I (40 microg/kg) or placebo at 1800 h. On both nights a somatostatin analog infusion (300 ng/kg x h) suppressed endogenous GH production, and three timed discrete GH pulses (total, 0.029 IU/kg x night) ensured identical GH levels. After recombinant human IGF-I administration, IGF-I levels and the IGF-I/IGF-binding protein-3 ratio increased [mean +/- SEM:IGF-I, 401 +/- 22 ng/ml; placebo, 256 +/- 20 ng/ml (P = 0.0002); IGF-I, 0.108 +/- 0.006; placebo, 0.074 +/- 0.004 (P = 0.0003), respectively], and insulin requirements decreased (IGF-I, 0.12 +/- 0.03; placebo, 0.23 +/- 0.03 U/kg x min; P = 0.008). The normal within-individual inverse relationships between insulin and IGF-binding protein-1 levels were observed (lag time 2 h: r = -0.34; P < 0.01). Yet despite reduced free insulin levels (8.5 +/- 1.5; placebo, 12.2 +/- 1.2 mU/liter; P = 0.03), IGF-binding protein-1 levels were reduced after recombinant human IGF-I administration (53.7 +/- 6.8; placebo, 82.2 +/- 11.8 ng/ml; P = 0.008). The largest reductions in free insulin levels after recombinant human IGF-I and thus putative improvement in insulin sensitivity occurred in subjects with the smallest increase in the plasma IGF-I/IGF-binding protein-3 ratio (r = 0.7; P = 0.03). Taken together, these data are consistent with the hypothesis that transcapillary movement of IGF-I (perhaps mediated by IGF-binding protein-1), out of the circulation facilitates altered insulin sensitivity. These data have important implications for risk-benefit assessment of recombinant human IGF-I therapy in type 1 diabetes mellitus.
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Affiliation(s)
- E C Crowne
- Bristol Royal Hospital for Sick Children, Bristol, United Kingdom BS2 8BJ
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Abstract
Diabetic retinopathy (DR) is the most frequent complication of diabetes and a leading cause of impaired vision in the Western world. There is general agreement that early diagnosis and treatment of DR can slow its progression and help to prevent blindness. However, as a result of its asymptomatic nature and its etiopathogenesis, which is still unclear due to its multifactorial complexity, DR-related blindness has a growing social impact in industrialized countries. Therefore, in order to gain a better understanding of this serious disease, the author performed an updated 10-year review of risk factors and management of DR in type 1 diabetes.
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Affiliation(s)
- C Giusti
- Department of Ophthalmology, Free University Campus Bio-Medico, Rome, Italy.
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Savage MO, Camacho-Hübner C, Dunger DB, Ranke MB, Ross RJ, Rosenfeld RG. Is there a medical need to explore the clinical use of insulin-like growth factor I? Growth Horm IGF Res 2001; 11 Suppl A:S65-S69. [PMID: 11527091 DOI: 10.1016/s1096-6374(01)80011-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Cloning of the insulin-like growth factor I (IGF-I) gene led to the development in 1987 of recombinant IGF-I available for clinical use. Trials were started targeting endocrine, metabolic and neurological disorders, and beneficial results have been demonstrated in IGF-I deficiency states caused by IGF-I gene deletion and growth hormone (GH) receptor deficiency, type 1 and type 2 diabetes mellitus, and severe insulin resistance syndromes. Results of equivocal benefit have also been reported in osteoporosis and amyotrophic lateral sclerosis. Recent encouraging data using the IGF-I-IGF-binding protein 3 (IGFBP-3) complex in diabetes mellitus suggest that this preparation may eventually replace recombinant free IGF-I. The lack of an established therapeutic indication for IGF-I has resulted in its supplies being severely limited. It will probably be decided during the next decade whether use of IGF-I or the IGF-I-IGFBP-3 complex becomes firmly established as an accepted endocrine therapy.
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Affiliation(s)
- M O Savage
- St Bartholomew's and the Royal London School of Medicine and Dentistry, UK.
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Quattrin T, Thrailkill K, Baker L, Kuntze J, Compton P, Martha P. Improvement of HbA1c without increased hypoglycemia in adolescents and young adults with type 1 diabetes mellitus treated with recombinant human insulin-like growth factor-I and insulin. rhIGF-I in IDDM Study Group. J Pediatr Endocrinol Metab 2001; 14:267-77. [PMID: 11308044 DOI: 10.1515/jpem.2001.14.3.267] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE A 12-week trial with insulin and rhIGF-I compared to insulin and placebo was conducted in patients with type 1 diabetes mellitus aged 11-66 years. We present the efficacy and safety data pertinent to the younger subset of participants (11-21 years). STUDY DESIGN The patients were randomized to receive s.c. insulin and either placebo or rhIGF-I at one of the following doses (microg/kg): 40 a.m./40 p.m., 80 a.m./40 p.m. or 80 a.m./60 p.m.). RESULTS The average decrease of HbA1c from baseline was higher (-1.3 +/- 0.2%) in the rhIGF-I treated group compared to the placebo group (-0.6 +/- 0.3%; p <0.05). This was associated with a significant decrease in daily insulin dose (U) of both Regular (rhIGF-I: -7 +/- 1; placebo: -1 +/- 1; p <0.01) and NPH (rhIGF-I: -4 +/- 2; placebo: +5 +/- 3; p <0.05). The incidence of hypoglycemia and weight gain were not increased. Edema, jaw pain and tachycardia were associated with rhIGF-I treatment, particularly at doses higher than 40 microg/kg b.i.d. Dose-related early worsening of retinopathy was observed in 11/55 patients in the rhIGF-I group, with resolution in the majority of them in the follow-up photographs. CONCLUSIONS These findings suggest a possible role for rhIGF-I co-therapy in adolescents and young adults with type 1 diabetes mellitus.
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Affiliation(s)
- T Quattrin
- Department of Pediatrics, Children's Hospital of Buffalo, State University of New York at Buffalo, 14222, USA.
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Leese G, Ellis J. Diabetic Eye Disease. J R Coll Physicians Edinb 2000. [DOI: 10.1177/147827150003000412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- G.P. Leese
- Consultant in Diabetes and Endocrinology, Ninewells Hospital and Medical School, Dundee
| | - J.D. Ellis
- Diabetes and Ophthalmology Unit, Ninewells Hospital and Medical School, Dundee
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Affiliation(s)
- C L Acerini
- Department of Paediatrics, University of Cambridge, Addenbrooke's Hospital, UK.
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Cusi K, DeFronzo R. Recombinant human insulin-like growth factor I treatment for 1 week improves metabolic control in type 2 diabetes by ameliorating hepatic and muscle insulin resistance. J Clin Endocrinol Metab 2000; 85:3077-84. [PMID: 10999789 DOI: 10.1210/jcem.85.9.6827] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The administration of recombinant human insulin-like growth factor I (rhIGF-I) reduces hyperglycemia and insulin requirements in subjects with severe insulin resistance syndromes and in patients with type 2 diabetes mellitus (T2DM). However, the mechanisms responsible for the improved metabolic control are incompletely understood. One proposed mechanism is that rhIGF-I therapy in T2DM may bypass early defects in insulin action (i.e. signal transduction), leading to improved hepatic and/or peripheral insulin sensitivity. To test this hypothesis, we used the euglycemic insulin clamp to measure the response to 7 days of rhIGF-I therapy (80 microg/kg, sc, twice daily) in eight poorly controlled T2DM subjects. rhIGF-I significantly improved fasting (203 +/- 12 vs. 134 +/- 14 mg/dL; P < 0.01) and day-long (0800-1700 h; 234 +/- 11 vs. 153 +/- 10 mg/dL; P < 0.01) plasma glucose levels. Basal endogenous glucose production decreased from 3.2 +/- 0.2 to 2.7 +/- 0.2 mg/kg lean body mass x min (P < 0.03) despite a concomitant decline in the fasting plasma insulin concentration from 13 +/- 5 to 5 +/- 1 microU/mL (P < 0.01). The decrement in basal endogenous glucose production was closely correlated with the decrement in fasting plasma glucose concentration (r = 0.78; P < 0.01). Whole body insulin-stimulated glucose disposal increased by 27% (from 5.6 +/- 0.8 to 7.1 +/- 0.8 mg/kg lean body mass x min; P < 0.01), but remained well below that observed in age- and weight-matched healthy subjects. The effects of rhIGF-I on endogenous glucose production and peripheral insulin sensitivity resemble those observed with intensified insulin regimens in T2DM. We conclude that 7 days of sc rhIGF-I improves glucose control by improving hepatic and muscle insulin sensitivity, but it remains markedly abnormal. This indicates that an intrinsic defect(s) responsible for insulin resistance in T2DM cannot be overcome by rhIGF-I treatment.
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Affiliation(s)
- K Cusi
- Department of Medicine, University of Texas Health Science Center, San Antonio 78284, USA.
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Woods KA, Camacho-Hübner C, Bergman RN, Barter D, Clark AJ, Savage MO. Effects of insulin-like growth factor I (IGF-I) therapy on body composition and insulin resistance in IGF-I gene deletion. J Clin Endocrinol Metab 2000; 85:1407-11. [PMID: 10770174 DOI: 10.1210/jcem.85.4.6495] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
We have recently reported a patient with a homozygous partial deletion of the insulin-like growth factor-I (IGF-I) gene, resulting in IGF-I deficiency, insulin resistance, and short stature. Recombinant human IGF-I (rhIGF-I) therapy has been shown to improve insulin sensitivity (Si) and growth in other causes of IGF-I deficiency. We now report results of 1 yr of rhIGF-I therapy on body composition, bone mineral density (BMD), insulin sensitivity, and linear growth in this patient. rhIGF-I therapy was initiated at age 16.07 yr (bone age, 14.2 yr), at a starting dose of 40 microg/kg daily, increasing after 3 months to 80 microg/kg daily. Body composition, BMD, markers of bone mineralization, and auxological parameters (height, weight) were measured at 0, 6, and 12 months after start of therapy. Si, acute insulin response to glucose, and glucose effectiveness were determined at baseline, 3 months, and 12 months into therapy. On IGF-I therapy, body mass index increased from 17 kg/m2 to 18.6 kg/m2. Body composition studies (dual-energy x-ray absorbtiometry) revealed an initial decrease in total body fat, from 19.9% at baseline to 15.1% at 6 months; but by 12 months of therapy, this had reversed, with an increase to 21.8%. Si, calculated using Bergman's minimal model, was substantially reduced at baseline at 1.45 x 10-4 min-1 (microU/mL) [normal value, 5.1 x 10-4 min 1 (lean adult male)]. rhIGF-I therapy resulted in a dose-related improvement of Si into the normal range (NR) (rhIGF-I dose: 40 microg/kg x day, Si = 2.06 x 10-4 min-l; rhIGF-I dose: 80 microg/kg x day, Si = 4.39 x 10-4 min-1). Baseline reduction in Si was accompanied by elevated acute insulin response to glucose, which also fell in a dose-dependent manner. Baseline BMD was severely reduced when compared with age-matched controls (-4.88 SD); however, calculation of bone mineral apparent density indicated that the true reduction in BMD was minimal. rhIGF-I therapy increased BMD by 17% and bone mineral apparent density by 7%, indicating that IGF-I has a greater effect on bone growth than bone mineralization. Bone turnover markers also increased on rhIGF-I; mean serum osteocalcin: 8.3 ng/mL pretreatment, 21.7 ng/mL after 6 months of rhIGF-I (NR for adult male, 3.4-9.1 ng/mL); mean bone specific alkaline phosphatase: 36.5 U/L pretreatment, 82.2 U/L after 6 months of therapy (NR for adult male, 15-41). Height velocity increased from 3.8 cm/yr pretreatment to 7.3 cm/yr on 80 microg/kg.day of rhIGF-I. In this patient with severe insulin resistance, therapy with rhIGF-I resulted in beneficial effects on Si, body composition, bone size, and linear growth. These results have implications for IGF-I therapy in a variety insulin resistant states.
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Affiliation(s)
- K A Woods
- Paediatric Endocrinology Section, Department of Endocrinology, St. Bartholomew's Hospital, London, United Kingdom
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