title: Relationship between muscle sympathetic nerve activity and large artery mechanical vessel wall properties in renal transplant patients.
abstract: OBJECTIVE
  Renal transplant recipients (RTX) show a major impairment of large artery elastic wall properties. Sympathetic overactivity present in patients with renal disease has been shown to alter large artery elasticity; however, in RTX, this issue has not been addressed. The present study therefore investigated a possible relationship between sympathetic activity and large artery distensibility in RTX.
  
  
  METHODS
  In 32 patients treated with calcineurin inhibitors (RTX-CI, cyclosporine n = 16, tacrolimus n = 16) mean arterial pressure (MAP, automatic sphygmomanometer), muscle sympathetic nerve activity (MSNA, microneurography) and distensibility coefficients of the brachial and carotid arteries (pulsed Doppler) were measured. Sixteen healthy volunteers (CTR), six patients with calcinneurin inhibitor-free immunosuppression (RTX-AZA) and 12 transplant patients after native kidney nephrectomy (RTX-NC) served as control groups.
  
  
  RESULTS
  RTX-CI significantly increased MSNA compared to CTR (36 +/- 3 versus 16 +/- 2 bursts/min, P < 0.05, mean +/- SEM). Both brachial and carotid artery distensibility were decreased in RTX-CI compared to CTR (7 +/- 1 versus 13 +/- 1 +/- 10(-3) /kPa and 17 +/- 1 versus 25 +/- 2 x 10(-3) /kPa, respectively, both P < 0.05). In RTX-CI, a significant inverse correlation between brachial, but not carotid artery distensibility and MSNA (r = -0.46, P < 0.01, r = -0.12, not significant, respectively) was found. Correlation between brachial artery distensibility and MSNA remained statistically significant on separate analysis of cyclosporine- or tacrolimus-treated RTX and after correction for arterial diameter, blood pressure, graft function, age and sex by stepwise multiple regression analysis. Results in RTX-AZA were similar to those in RTX-CI. In contrast, in RTX-NC with MSNA not significantly different from CON (16.6 +/- 2.0 bursts/min), brachial artery distensibility was significantly higher compared to RTX-CI and RTX-AZA (14.2 +/- 2.0 x 10(-3) /kPa, P < 0.05, respectively).
  
  
  CONCLUSIONS
  Increased sympathetic nerve activity in renal transplant patients is related to decreased distensibility of the muscular type brachial artery, but not the elastic type carotid artery.
authors.affiliation: Department of Internal Medicine D, University of Münster, Münster, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Kosch
authors.forename: Michael
authors.initials: M
authors.lastname: Barenbrock
authors.forename: Klaus
authors.initials: K
authors.lastname: Kisters
authors.forename: Karl Heinz
authors.initials: KH
authors.lastname: Rahn
authors.forename: Martin
authors.initials: M
authors.lastname: Hausberg
mesh_terms: D000328:Adult; D001379:Azathioprine / Q000627:therapeutic use; D001916:Brachial Artery / Q000503:physiopathology*; D065095:Calcineurin Inhibitors; D017536:Carotid Artery, Common / Q000503:physiopathology*; D016572:Cyclosporine / Q000627:therapeutic use; D004548:Elasticity; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000294:innervation*; D009392:Nephrectomy; D011184:Postoperative Period; D012016:Reference Values; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D016559:Tacrolimus / Q000627:therapeutic use; D014666:Vasomotor System / Q000503:physiopathology*
chemical_list: D065095:Calcineurin Inhibitors; D007166:Immunosuppressive Agents; D016572:Cyclosporine; D001379:Azathioprine; D016559:Tacrolimus