Somatotrope GHRH/GH/IGF-1 axis at the crossroads between immunosenescence and frailty.
Immunosenescence, characterized by complex modifications of immunity with age, could be related to frailty syndrome in elderly individuals, leading to an inadequate response to minimal aggression. Functional decline (i.e., the loss of ability to perform activities of daily living) is related to frailty and decreased physiological reserves and is a frequent outcome of hospitalization in older patients. Links between immunosenescence and frailty have been explored and 20 immunological parameters, including insulin-like growth factor-1 (IGF-1), thymopoeisis, and telomere length, were shown to be affected in elderly patients with functional decline. A strong relationship between IGF-1 and thymic ouput was evidenced. IGF-1, a mediator of growth hormone (GH), was subsequently shown to induce interleukin-7 secretion in cultured primary human thymic epithelial cells. We are exploring the stress hypothesis in which an acute stressor is used as the discriminator of frailty susceptibility. GH can counteract the deleterious immunosuppressive effects of stress-induced steroids. Under nonstress conditions, the immunosenescent system preserves physiological responses, while under stress conditions, the combination of immunosenescence and a defect in the somatotrope axis might lead to functional decline.
GIGA Research Institute, University of Liège, Liège, Belgium.
Gwennaelle
G
Bodart
GIGA Research Institute, University of Liège, Liège, Belgium.
Lindsay
L
Goffinet
GIGA Research Institute, University of Liège, Liège, Belgium.
Gabriel
G
Morrhaye
GIGA Research Institute, University of Liège, Liège, Belgium.
Khalil
K
Farhat
Department of Geriatrics, University Hospital of Mont-Godinne, NARILIS-Namur Research Institute for Life Sciences, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
Marie
M
de Saint-Hubert
Unit of Research on Cellular Biology, NARILIS-Namur Research Institute for Life Sciences, University of Namur (FUNDP), Namur, Belgium.
Florence
F
Debacq-Chainiaux
Department of Geriatrics, University Hospital of Mont-Godinne, NARILIS-Namur Research Institute for Life Sciences, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
Christian
C
Swine
GIGA Research Institute, University of Liège, Liège, Belgium.
Vincent
V
Geenen
GIGA Research Institute, University of Liège, Liège, Belgium.
Henri J
HJ
Martens
D000203:Activities of Daily Living; D000369:Aged, 80 and over; D015415:Biomarkers; D002478:Cells, Cultured; D016330:Frail Elderly; D013006:Growth Hormone / Q000235:genetics / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000378:metabolism*; D006410:Hematopoiesis / Q000276:immunology / Q000502:physiology; D006801:Humans; D000068884:Immunosenescence / Q000276:immunology / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D015851:Interleukin-7 / Q000378:metabolism; D013312:Stress, Physiological / Q000502:physiology; D059505:Telomere Homeostasis / Q000502:physiology
D015415:Biomarkers; C508605:IL7 protein, human; D015851:Interleukin-7; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone
GHRH; IGF-1; aging; frailty; growth hormone; growth-hormone-releasing hormone; immunosenescence; insulin-like growth factor-1