Impact of 14-day bed rest on serum adipokines and low-grade inflammation in younger and older adults

Abstract

Ageing and inactivity both contribute to systemic inflammation, but the effects of inactivity on inflammation in healthy elderly individuals have not been elucidated. We hypothesised that 14-day bed rest could affect the pro- and anti-inflammatory markers in young subjects differently than in older adults. A short-term 14-day horizontal bed rest study (BR14) has been used as a model of inactivity in two groups of healthy male volunteers: 7 aged 18-30 years (young) and 16 aged 55-65 years (older adults). The effects of inactivity on inflammation were compared. Key low-grade inflammation mediators, tumour necrosis factor α (TNF-α), interleukin-6 (IL-6), visfatin, resistin, and anti-inflammatory adiponectin were measured in fasting serum samples, collected at baseline (BDC) and post BR14. Young responded to BR14 by increasing serum visfatin and resistin while older adults responded to BR14 by increasing IL-6 and TNF-α. In addition, serum adiponectin increased in all participants. Data from correlation analysis demonstrated positive association between Δ serum visfatin and Δ IL-6 in both groups, while Δ serum adiponectin was negatively associated with Δ TNF-α in young and positively associated with Δ resistin in the older adults. As little as 14 days of complete physical inactivity (BR14) negatively affected markers of low-grade inflammation in both groups, but the inflammation after BR14 was more pronounced in older adults. The effect of BR14 on IL-6 and resistin differed between young and older adults. Inflammatory responses to BR14 in older adults differed from those reported in the literature for obese or subjects in pathological states, suggesting potentially different mechanisms between inactivity- and obesity-induced inflammations.

Muscle protein breakdown is impaired during immobilization compared to during a subsequent retraining period in older men: no effect of anti-inflammatory medication

“…Given that inactivity and bed rest have been shown to increase systemic inflammation [7,22], we hypothesized that NF-kB signaling would increase after 2 weeks of immobilization and that this response would be attenuated by NSAID treatment. However, no changes in cytosolic or nuclear NF-kB p65 were observed in any of the groups, suggesting that local inflammation was not increased by the unilateral leg immobilization.…”

Effects of short-term dry immersion on bone remodeling markers, insulin and adipokines

“…To our knowledge, very few studies investigated this adipokine under ground-based models of prolonged conditions of microgravity. The effects of bed rest on serum adipokines and low-grade inflammation were shown to be age-dependent [ 50 ]. Indeed, in this latter study, young subjects (18–30 years) responded to 14-days bed rest by increasing serum visfatin and resistin while there was no difference in older adults (53–65 years), these latter subjects increasing rather in IL-6 and TNF-α.…”

Loss of maximal explosive power of lower limbs after 2 weeks of disuse and incomplete recovery after retraining in older adults

“…) and adipokine values (Jurdana et al . ) in older adults compared to young people has been investigated by our group in a recent BR study. Also, we have examined the combined effects of ageing and disuse, followed by physical retraining, on muscle mass and performance (Pisot et al .…”