Muscle strength but not functional capacity is associated with plasma interleukin-6 levels of community-dwelling elderly women

Abstract

The association of plasma interleukin-6 (IL-6) levels, muscle strength and functional capacity was investigated in a crosssectional study of community-dwelling elderly women from Belo Horizonte, Brazil. Elderly people who present controlled chronic diseases with no negative impact on physical, psychosocial and mental functionality are considered to be community-dwelling. Psychological and social stress due to unsuccessfully aging can represent a risk for immune system disfunctions. IL-6 levels, isokinetic muscle strength of knee flexion/extension, and functional tests to determine time required to rise from a chair and gait velocity were measured in 57 participants (71.21 ± 7.38 years). Serum levels of IL-6 were measured in duplicate and were performed within one single assay (mouse monoclonal antibody against IL-6; High-Sensitivity, Quantikine ® , R & D Systems, USA; intra-assay coefficient of variance = 6.9-7.4%; interassay coefficient of variance = 9.6-6.5%; sensitivity = 0.016-0.110 pg/ mL; mean = 0.039 pg/mL). Muscle strength was assessed with the isokinetic dynamometer Biodex System 3 Pro ® . After the Shapiro-Wilk normality test was applied, correlations were investigated using Spearman and Kruskal-Wallis tests. Post hoc analysis was performed using the Dunn test. A significant negative correlation was observed between plasma IL-6 levels (1.95 ± 1.77 pg/mL) and muscle strength for knee flexion (70.70 ± 21.14%; r = -0.265; P = 0.047) and extension (271.84 ± 67.85%; r = -0.315; P = 0.017). No significant correlation was observed between IL-6 levels and the functional tests (time to rise from a chair = 14.65 ± 2.82 s and gait velocity = 0.95 ± 0.14 m/s). These results suggest that IL-6 is associated with reduced muscle strength.

Effects of 174 G/C polymorphism in the promoter region of the interleukin-6 gene on plasma IL-6 levels and muscle strength in elderly women

“…In this respect, the genes involved in regulating the inflammatory process, which increases with age, may contribute to individual variation in plasma cytokine levels and muscle strength in the elderly. However, despite evidence pointing at the action of IL-6 as one of the factors related to the reduction of muscle mass and muscle strength (sarcopenia) (1,(20)(21)(22) and the importance of genetic variation in the regulation of this cytokine, studies investigating the impact of the -174 G/C polymorphism of the IL6 gene on the variables of muscle performance are scarce.…”

Avaliação da Força Muscular de Diferentes Populações: Uma Revisão de Literatura

“…Alguns com grupo de estudo formado por jovens do sexo feminino 1,21,[23][24][25][26][27] , jovens do sexo masculino 19,28,29,30 , e outros por indivíduos idosos de ambos os sexos 5,7,[12][13][14][15][16]20,31,32 . Já outros estudos foram voltados para a população de indivíduos com patologias 2,6,8,33,34,35 e em pós-operatório 9,36 .…”

“…18,27,28 . Quanto a frequência de avaliações, uma única avaliação foi a mais recorrente 2,3,4,6,8,9,[11][12][13][14]16,28,[30][31][32][33][34][35][36][37][38] . Outros estudos abordaram avaliações pré e pós-intervenção, sendo estas treinamento de força 7,10,17,20,25,26 ; eletroestimulação 24 , suplementação 23 e alongamento 1,29 .…”

Handgrip strength, functionality and plasma levels of IL-6 in elderly women

“…Unlike functional tests of gait speed and sitting and standing, there was no correlation (26) demonstrated, indicating that functionality encompasses a harmonious integration of various sensory motor systems and not only muscle tissue. Furthermore, results of the study by Oliveira et al (26) indicated a catabolic action of inflammatory cytokines on muscle fibers. A study by Lustosa et al (27) that assessed muscle strength with an isokinetic dynamometer (considered the gold standard tool for this measure) revealed an association between increased inflammatory cytokines and low muscular and functional performance in elderly individuals.…”

“…Decreased HGS has been previously identified as strong biomarker for aging (12,16,20), indicating a negative impact of muscle strength loss on functional capacity (26). This measure provides an approximation of total body muscle force as it correlates with elbow flexion strength, extension force of the leg, and trunk strength (9).…”