Document Detail


IGF-I but not insulin inhibits apoptosis at a low concentration in vascular smooth muscle cells.
MedLine Citation:
PMID:  14596678     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Apoptosis of vascular smooth muscle cells (VSMCs) is of importance in the development of diabetic angiopathy. Our aim was to evaluate the effect of insulin and IGF-I on apoptosis in VSMCs. Rat aortic VSMCs were used and apoptosis was induced by serum starvation. As apoptotic markers we measured caspase-3 activity, histone-associated DNA fragments by ELISA and nuclear morphology by DAPI (4',6-diamidino-2-phenylindole) staining. Phosphorylation of IGF-I receptors was evaluated by Western blot. Serum starvation had increased caspase-3 activity even after 3 h. The highest activity was found after 3-12 h. IGF-I 10(-9 )M inhibited serum starvation-induced caspase-3 activity with a maximal effect after 12 h. When studied after starvation for 12 h, significant inhibitory effects on caspase-3 were found at IGF-I concentrations of 10(-8)-10(-7) M (P<0.01) and at an insulin concentration of 10(-6 )M (P<0.01). DNA fragmentation was detected by ELISA after 24 h and chromatin condensation and nuclear fragmentation by DAPI staining after 24 and 48 h respectively. IGF-I dose-dependently reduced apoptosis evaluated by ELISA, reaching a maximal effect at 10(-9) M. Insulin reduced apoptosis but the effect was weaker and a higher concentration was needed. IGF-I (10(-8 )M) and insulin at a very high concentration (10(-6) M) phosphorylated IGF-I receptors. Taken together, IGF-I and insulin have antiapoptotic effects on VSMCs but the effect of insulin is only found at high unphysiological concentration.
Authors:
R Jamali; M Bao; H J Arnqvist
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of endocrinology     Volume:  179     ISSN:  0022-0795     ISO Abbreviation:  J. Endocrinol.     Publication Date:  2003 Nov 
Date Detail:
Created Date:  2003-11-04     Completed Date:  2004-01-27     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  0375363     Medline TA:  J Endocrinol     Country:  England    
Other Details:
Languages:  eng     Pagination:  267-74     Citation Subset:  IM    
Affiliation:
Division of Cell Biology, Department of Biomedicine and Surgery, Faculty of Health Sciences, Linköping University, Linköping, Sweden.
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MeSH Terms
Descriptor/Qualifier:
Animals
Aorta
Apoptosis / drug effects
Blotting, Western / methods
Caspase 3
Caspases / analysis
Cells, Cultured
Enzyme-Linked Immunosorbent Assay / methods
Insulin / pharmacology*
Insulin-Like Growth Factor I / pharmacology*
Male
Muscle, Smooth, Vascular / cytology*,  drug effects,  metabolism
Phosphorylation
Rats
Rats, Sprague-Dawley
Receptor, IGF Type 1 / metabolism
Chemical
Reg. No./Substance:
11061-68-0/Insulin; 67763-96-6/Insulin-Like Growth Factor I; EC 2.7.10.1/Receptor, IGF Type 1; EC 3.4.22.-/Casp3 protein, rat; EC 3.4.22.-/Caspase 3; EC 3.4.22.-/Caspases

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