title: Healthy aging is associated with unaltered production of immunoreactive growth hormone but impaired neuroimmunomodulation.
abstract: BACKGROUND
  Both endocrine and immune systems are continuously remodeled during aging.
  
  
  OBJECTIVE
  Here, we investigated to what extent adrenal and somatosenescence are associated reciprocal changes in the immune system during strictly healthy aging.
  
  
  METHODS
  Forty-six elderly subjects and 33 young adults were recruited according to the health criteria of the SENIEUR protocol. Peripheral blood mononuclear cells were isolated and stimulated in vitro with lipopolysaccharide or phytohemagglutinin to assess the production of immunoreactive growth hormone (GH). Peripheral sensitivity to steroids was assessed in vitro by dexamethasone-, cortisol- or dehydroepiandrosterone (DHEA)-induced inhibition of T-cell proliferation. DHEA and GH levels were measured by radioimmunoassays.
  
  
  RESULTS
  Healthy elderly had lower salivary DHEA and serum GH levels (somatosenescence). They presented reduced T-cell sensitivity to dexamethasone but similar cellular sensitivities to cortisol and DHEA. Their cells produced similar levels of immunoreactive GH compared to the cells of young adults.
  
  
  CONCLUSIONS
  These data indicate that healthy aging is associated with adrenal and somatosenescence as well as impaired neuroendocrine immunoregulation at the level of the lymphocyte. In addition, somatosenescence may not be associated with a reciprocal decline in immunoreactive GH.
authors.affiliation: Instituto de Pesquisas Biomédicas, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Clarice
authors.initials: C
authors.lastname: Luz
authors.forename: Diego
authors.initials: D
authors.lastname: Collaziol
authors.forename: Thales
authors.initials: T
authors.lastname: Preissler
authors.forename: Ivana M
authors.initials: IM
authors.lastname: da Cruz
authors.forename: Luiz
authors.initials: L
authors.lastname: Glock
authors.forename: Moisés E
authors.initials: ME
authors.lastname: Bauer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000276:immunology* / Q000378:metabolism; D019540:Area Under Curve; D049109:Cell Proliferation; D002478:Cells, Cultured; D003687:Dehydroepiandrosterone / Q000032:analysis / Q000378:metabolism; D005260:Female; D005938:Glucocorticoids / Q000378:metabolism; D019382:Human Growth Hormone / Q000096:biosynthesis* / Q000097:blood; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D015213:Neuroimmunomodulation / Q000502:physiology*; D012463:Saliva / Q000737:chemistry; D013601:T-Lymphocytes / Q000378:metabolism
chemical_list: D005938:Glucocorticoids; D019382:Human Growth Hormone; D003687:Dehydroepiandrosterone