title: Circadian rhythms in rheumatology--a glucocorticoid perspective.
abstract: The hypothalamic-pituitary-adrenal (HPA) axis plays an important role in regulating and controlling immune responses. Dysfunction of the HPA axis has been implicated in the pathogenesis of rheumatoid arthritis (RA) and other rheumatic diseases. The impact of glucocorticoid (GC) therapy on HPA axis function also remains a matter of concern, particularly for longer treatment duration. Knowledge of circadian rhythms and the influence of GC in rheumatology is important: on the one hand we aim for optimal treatment of the daily undulating inflammatory symptoms, for example morning stiffness and swelling; on the other, we wish to disturb the HPA axis as little as possible. This review describes circadian rhythms in RA and other chronic inflammatory diseases, dysfunction of the HPA axis in RA and other rheumatic diseases and the recent concept of the hepato-hypothalamic-pituitary-adrenal-renal axis, the problem of adrenal suppression by GC therapy and how it can be avoided, and evidence that chronotherapy with modified release prednisone effective at 02:00 a.m. can inhibit proinflammatory sequelae of nocturnal inflammation better compared with GC administration in the morning but does not increase the risk of HPA axis insufficiency in RA.
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: Spies
authors.forename: Rainer H
authors.initials: RH
authors.lastname: Straub
authors.forename: Maurizio
authors.initials: M
authors.lastname: Cutolo
authors.forename: Frank
authors.initials: F
authors.lastname: Buttgereit
mesh_terms: D043205:11-beta-Hydroxysteroid Dehydrogenase Type 1 / Q000502:physiology; D000309:Adrenal Insufficiency / Q000139:chemically induced; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000503:physiopathology; D002940:Circadian Rhythm / Q000502:physiology*; D003346:Corticotropin-Releasing Hormone; D055870:Drug Chronotherapy; D005938:Glucocorticoids / Q000008:administration & dosage* / Q000378:metabolism; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects* / Q000503:physiopathology; D007249:Inflammation / Q000188:drug therapy* / Q000503:physiopathology; D015850:Interleukin-6 / Q000502:physiology; D008099:Liver / Q000503:physiopathology; D015337:Multicenter Studies as Topic; D010913:Pituitary-Adrenal System / Q000187:drug effects* / Q000503:physiopathology; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology
chemical_list: D005938:Glucocorticoids; C508600:IL6 protein, human; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D003346:Corticotropin-Releasing Hormone; D043205:11-beta-Hydroxysteroid Dehydrogenase Type 1; D006854:Hydrocortisone