title: Stress-related reduction in personal mastery is associated with reduced immune cell beta2-adrenergic receptor sensitivity.
abstract: BACKGROUND
  A growing body of literature suggests that caregiving burden is associated with impaired immune system functioning, which may contribute to elevated morbidity and mortality risk among dementia caregivers. However, potential mechanisms linking these relationships are not well understood. The purpose of this study was to investigate whether stress-related experience of depressive symptoms and reductions in personal mastery were related to alterations in ss2-adrenergic receptor sensitivity.
  
  
  METHODS
  Spousal Alzheimer's caregivers (N = 106) completed measures assessing the extent to which they felt overloaded by their caregiving responsibilities, experienced depressive symptoms, and believed their life circumstances were under their control. We hypothesized that caregivers reporting elevated stress would report increased depressive symptoms and reduced mastery, which in turn would be associated with reduced ss2- adrenergic receptor sensitivity on peripheral blood mononuclear cells (PBMC), as assessed by in vitro isoproterenol stimulation.
  
  
  RESULTS
  Regression analyses indicated that overload was negatively associated with mastery (beta = -0.36, p = 0.001) and receptor sensitivity (beta = -0.24, p = 0.030), whereas mastery was positively associated with receptor sensitivity (beta = 0.29, p = 0.005). Finally, the relationship between overload and receptor sensitivity diminished upon simultaneous entry of mastery. Sobel's test confirmed that mastery significantly mediated some of the relationship between overload and receptor sensitivity (z = -2.02, p = 0.044).
  
  
  CONCLUSIONS
  These results suggest that a reduced sense of mastery may help explain the association between caregiving burden and reduced immune cell ss2-receptor sensitivity.
authors.affiliation: Department of Psychiatry, University of California at San Diego, La Jolla, CA 92093-0680, U.S.A. bmausbach@ucsd.edu
authors.forename: Brent T
authors.initials: BT
authors.lastname: Mausbach
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Mills
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Patterson
authors.forename: Kirstin
authors.initials: K
authors.lastname: Aschbacher
authors.forename: Joel E
authors.initials: JE
authors.lastname: Dimsdale
authors.forename: Sonia
authors.initials: S
authors.lastname: Ancoli-Israel
authors.forename: Roland
authors.initials: R
authors.lastname: von Känel
authors.forename: Igor
authors.initials: I
authors.lastname: Grant
mesh_terms: D000223:Adaptation, Psychological; D000368:Aged; D000544:Alzheimer Disease / Q000628:therapy*; D001291:Attitude of Health Personnel; D017028:Caregivers / Q000523:psychology* / Q000706:statistics & numerical data*; D005260:Female; D006304:Health Status; D006801:Humans; D007389:Internal-External Control; D007545:Isoproterenol / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology; D008297:Male; D011569:Psychiatric Status Rating Scales; D018343:Receptors, Adrenergic, beta-2 / Q000097:blood* / Q000187:drug effects*; D012044:Regression Analysis; D013315:Stress, Psychological / Q000097:blood / Q000276:immunology / Q000523:psychology*; D011795:Surveys and Questionnaires
chemical_list: D018343:Receptors, Adrenergic, beta-2; D007545:Isoproterenol