title: Adrenergic mechanisms and remodeling of subcutaneous small resistance arteries in humans.
abstract: BACKGROUND
  Vascular structural alterations in small resistance arteries of patients with essential hypertension (EH) are mostly characterized by inward eutrophic remodeling. In fact, no difference in the smooth muscle cell volume (CV) between normotensive subjects (NT) and essential hypertensive patients was observed. However, experimental models of hypertension with chronic infusion of agonists of adrenergic receptors were characterized by the presence of smooth muscle cell hypertrophy or hyperplasia. Recently, we have observed the presence of vascular smooth muscle cell hypertrophy in patients with renovascular hypertension.
  
  
  OBJECTIVE
  The aim of the study to investigate the structural characteristics of subcutaneous small resistance arteries of NT, of EH, and of patients with phaeochromocytoma (Phaeo).
  
  
  METHODS
  Thirty Phaeo, 30 NT and 30 EH were included in the study. A biopsy of subcutaneous fat was taken from all subjects. Small resistance arteries (relaxed diameter 160-280 microm) were dissected and mounted on a micromyograph and the media : lumen ratio was calculated. In nine Phaeo, nine NT and 13 EH the cell volume was measured by an unbiased stereological principle, the 'disector' method. RESULTS No difference in smooth muscle cell volume was observed between groups. However, inward remodeling in Phaeo was less marked than in EH, although the increase in media : lumen ratio was similar compared with NT. However, the lack of changes in media cross-sectional area, compared with NT, suggest that there has been little hypertrophy, the changes observed thus being eutrophic.
  
  
  CONCLUSIONS
  Our data show, based on a reasonably large sample, that a pronounced activation of the adrenergic system is not associated with vascular smooth muscle cell hypertrophy or hyperplasia in humans. It is therefore possible that adrenergic mechanisms may have a relevant role in the development of eutrophic remodeling in small vessels.
authors.affiliation: Department of Medical and Surgical Sciences, University of Brescia, Italy.
authors.forename: Enzo
authors.initials: E
authors.lastname: Porteri
authors.forename: Damiano
authors.initials: D
authors.lastname: Rizzoni
authors.forename: Michael John
authors.initials: MJ
authors.lastname: Mulvany
authors.forename: Carolina
authors.initials: C
authors.lastname: De Ciuceis
authors.forename: Intissar
authors.initials: I
authors.lastname: Sleiman
authors.forename: Gianluca E
authors.initials: GE
authors.lastname: Boari
authors.forename: Maurizio
authors.initials: M
authors.lastname: Castellano
authors.forename: Maria Lorenza
authors.initials: ML
authors.lastname: Muiesan
authors.forename: Francesca
authors.initials: F
authors.lastname: Zani
authors.forename: Enrico Agabiti
authors.initials: EA
authors.lastname: Rosei
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000503:physiopathology* / Q000601:surgery; D000315:Adrenalectomy; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001158:Arteries / Q000503:physiopathology* / Q000601:surgery; D015415:Biomarkers / Q000652:urine; D001794:Blood Pressure / Q000502:physiology; D018660:Blood Pressure Monitoring, Ambulatory; D048429:Cell Size / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology; D003971:Diastole / Q000502:physiology; D004548:Elasticity; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism / Q000503:physiopathology; D004837:Epinephrine / Q000652:urine; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism / Q000503:physiopathology; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000473:pathology; D009638:Norepinephrine / Q000652:urine; D010673:Pheochromocytoma / Q000503:physiopathology* / Q000601:surgery; D013599:Systole / Q000502:physiology; D016896:Treatment Outcome; D014655:Vascular Resistance / Q000502:physiology*
chemical_list: D000959:Antihypertensive Agents; D015415:Biomarkers; D009638:Norepinephrine; D004837:Epinephrine