title: Phenotype modulation in cultures of vascular smooth muscle cells from diabetic rats: association with increased nitric oxide synthase expression and superoxide anion generation.
abstract: Proliferative modification of vascular smooth muscle cell (vSMC) and impaired bioavailability of nitric oxide (NO) have both been proposed among the mechanisms linking diabetes and atherosclerosis. However, diabetes induced modifications in phenotype and nitric oxide synthase(s) (NOS) expression and activity in vSMC have not been fully characterized. In this study, cell morphology, proliferative response to serum, alpha-SMactin levels, eNOS expression and activity, cGMP intracellular content, and superoxide anion release were measured in cultures of vSMC obtained from aorta medial layer of ten diabetic (90% pancreatectomy, DR) and ten control (sham surgery, CR) rats. Vascular SMC from DR showed a less evident "hill and valley" culture morphology, increased growth response to serum, greater saturation density, and lower levels of alpha-SMactin. In the same cells, as compared to CR cells, eNOS mRNA levels and NOS activity were increased, while intracellular cGMP level was lower and superoxide anion production was significantly greater. These data indicate that chronic hyperglycemia might induce, in the vascular wall, an increased number of vSMC proliferative clones which persist in culture and are associated with increased eNOS expression and activity. However, upregulation of eNOS and increased NO synthesis occur in the presence of a marked concomitant increase of O(2-) production. Since NO bioavailability, as reflected by cGMP levels, was not increased in DR cells, it is tempting to hypothesize that the proliferative phenotype observed in DR cells is associated with a redox imbalance responsible quenching and/or trapping of NO, with the consequent loss of its biological activity.
authors.affiliation: Dipartimento di Biomorfologia, Università di Chieti, Italy.
authors.forename: Assunta
authors.initials: A
authors.lastname: Pandolfi
authors.forename: Alfredo
authors.initials: A
authors.lastname: Grilli
authors.forename: Carlo
authors.initials: C
authors.lastname: Cilli
authors.forename: Antonia
authors.initials: A
authors.lastname: Patruno
authors.forename: Andrea
authors.initials: A
authors.lastname: Giaccari
authors.forename: Sara
authors.initials: S
authors.lastname: Di Silvestre
authors.forename: Maria Anna
authors.initials: MA
authors.lastname: De Lutiis
authors.forename: Giuliana
authors.initials: G
authors.lastname: Pellegrini
authors.forename: Fabio
authors.initials: F
authors.lastname: Capani
authors.forename: Agostino
authors.initials: A
authors.lastname: Consoli
authors.forename: Mario
authors.initials: M
authors.lastname: Felaco
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic; D001786:Blood Glucose / Q000032:analysis; D001790:Blood Physiological Phenomena; D002452:Cell Count; D002478:Cells, Cultured; D002956:Citrulline / Q000096:biosynthesis; D003599:Cytoskeleton / Q000648:ultrastructure; D003920:Diabetes Mellitus / Q000209:etiology / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005434:Flow Cytometry; D007328:Insulin / Q000097:blood; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology*; D032389:Myocytes, Smooth Muscle / Q000201:enzymology / Q000473:pathology / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III; D010180:Pancreatectomy / Q000379:methods; D010641:Phenotype; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013481:Superoxides / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D012333:RNA, Messenger; D013481:Superoxides; D002956:Citrulline; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat