Sarra Baëhl1, Hugo Garneau1, Aurélie Le Page1, Dominique Lorrain1, Isabelle Viens1, Amy Svotelis2, Janet M Lord3, Anna C Phillips3, François Cabana2, Anis Larbi4, Gilles Dupuis5, Tamàs Fülöp6. 1. Division of Geriatrics and Research Center on Aging, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada. 2. Orthopedic Surgery Division, Centre Hospitalier Universitaire de l'Université de Sherbrooke, Sherbrooke (CHUS), Quebec J1H 5N4, Canada. 3. MRC-ARUK Centre for Musculoskeletal Ageing Research, University of Birmingham, Birmingham, United Kingdom. 4. Singapore Immunology Network (SIgN), Biopolis, Agency for Science Technology and Research (A*STAR), Singapore. 5. Department of Biochemistry, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada. 6. Division of Geriatrics and Research Center on Aging, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada. Electronic address: Tamas.Fulop@Usherbrooke.ca.
Abstract
BACKGROUND: Fracture of the hip (HF) is a significant cause of morbidity and mortality in elderly individuals. HF is an acute stress that triggers a state of inflammation which may affect immune responses and physical recovery. METHODS: Longitudinal study of the impact of HF on the functions of polymorphonuclear neutrophils (PMNs) in elderly subjects. Data were recorded prior to surgery, 6weeks and 6months later. RESULTS: PMN functions were severely impaired shortly after HF (chemotaxis, phagocytosis, superoxide production) but there was a time-related recovery of some PMN functions (chemotaxis, phagocytosis) over time, except in the case of superoxide production. Whereas FcγRII (CD32) expression remained unchanged, FcγRIII (CD16) increased from low values before surgery to levels of controls 6months post-surgery. This was also the case for the C5a complement receptor and CD11b. TLR2 and TLR4 expressions were unchanged. Cytokine and chemokine secretions by stimulated PMN were altered. TNFα and IL-10 secretions were increased following HF but IL-8 secretion was decreased. Impaired PMN functions prior to surgery were related to alterations in PI3K and NF-κB signaling pathways. Recovery of these functions paralleled increased PI3K activity, although superoxide production remained low. Sustained activation of the NF-κB pathway by TNFα has been reported to involve upregulation of IKKβ kinase activity. Activated IKKβ kinase inhibits ERK1/2 and results in concomitant downstream inhibition of NADPH oxidase complex which can account for sustained impaired production of ROS in HF patients. CONCLUSION: Our data showed that the stress caused by HF negatively affects initial PMN responses shortly after the event and that may negatively influence clinical outcomes such as resolving long-term inflammation and recovery, as well as explaining susceptibility to opportunistic infections.
BACKGROUND:Fracture of the hip (HF) is a significant cause of morbidity and mortality in elderly individuals. HF is an acute stress that triggers a state of inflammation which may affect immune responses and physical recovery. METHODS: Longitudinal study of the impact of HF on the functions of polymorphonuclear neutrophils (PMNs) in elderly subjects. Data were recorded prior to surgery, 6weeks and 6months later. RESULTS: PMN functions were severely impaired shortly after HF (chemotaxis, phagocytosis, superoxide production) but there was a time-related recovery of some PMN functions (chemotaxis, phagocytosis) over time, except in the case of superoxide production. Whereas FcγRII (CD32) expression remained unchanged, FcγRIII (CD16) increased from low values before surgery to levels of controls 6months post-surgery. This was also the case for the C5a complement receptor and CD11b. TLR2 and TLR4 expressions were unchanged. Cytokine and chemokine secretions by stimulated PMN were altered. TNFα and IL-10 secretions were increased following HF but IL-8 secretion was decreased. Impaired PMN functions prior to surgery were related to alterations in PI3K and NF-κB signaling pathways. Recovery of these functions paralleled increased PI3K activity, although superoxide production remained low. Sustained activation of the NF-κB pathway by TNFα has been reported to involve upregulation of IKKβ kinase activity. Activated IKKβ kinase inhibits ERK1/2 and results in concomitant downstream inhibition of NADPH oxidase complex which can account for sustained impaired production of ROS in HF patients. CONCLUSION: Our data showed that the stress caused by HF negatively affects initial PMN responses shortly after the event and that may negatively influence clinical outcomes such as resolving long-term inflammation and recovery, as well as explaining susceptibility to opportunistic infections.
Authors: Aurélie Le Page; Hugo Garneau; Gilles Dupuis; Eric H Frost; Anis Larbi; Jacek M Witkowski; Graham Pawelec; Tamàs Fülöp Journal: Front Immunol Date: 2017-07-07 Impact factor: 7.561
Authors: Usma Munawara; Michael Catanzaro; Weili Xu; Crystal Tan; Katsuiku Hirokawa; Nabil Bosco; David Dumoulin; Abdelouahed Khalil; Anis Larbi; Simon Lévesque; Charles Ramassamy; Annelise E Barron; Stephen Cunnane; Pascale B Beauregard; Jean-Pierre Bellenger; Serafim Rodrigues; Mathieu Desroches; Jacek M Witkowski; Benoit Laurent; Eric H Frost; Tamas Fulop Journal: Immun Ageing Date: 2021-06-21 Impact factor: 6.400