New insights into the effects of irisin levels in HIV-infected subjects: correlation with adiposity, fat-free mass, and strength parameters

ABSTRACT Objective Patients infected with the human immunodeficiency virus (HIV) have an increased risk of metabolic disorders and alterations on irisin levels. Therefore, the purpose of the current investigation was to quantify the circulating irisin concentration in HIV-infected subjects under highly active antiretroviral therapy and to determine possible correlations between irisin levels with fat mass, fat-free mass, body mass index (BMI), and muscle strength. Subjects and methods Cross-sectional study of 10 men (36.7 ± 11.3 years) and 10 women (42.5 ± 10.3 years) infected with HIV, recruited from the Specialized Service Center in the State Center of Reference for High and Medium Complexity. Blood samples were collected to determine plasma irisin levels, glucose, HDL, total cholesterol, triglycerides, and LDL. Body composition (fat mass, fat-free mass) and anthropometrics (body mass index; BMI) were measured by bioelectrical impedance. Muscle strength was assessed using a mechanic hand dynamometer and one maximum repetition tests. Results Irisin levels correlated positively with fat mass (r = 0.67; p = 0.001) and BMI (r = 0.48; p = 0.036). In contrast, there was an inverse correlation between irisin levels and fat-free mass (r = -0.41; p = 0.008) and five strength parameters: right hand grip (r = -0.46; p = 0.044); left hand grip (r = -0.50; p = 0.027), relative hand grip (r = -0.79; p = 0.001), bench press (r = -0.58; p = 0.009), leg press (r = -0.40; p = 0.085), and biceps curl (r = -0.059; p = 0.009). Conclusion Irisin levels correlated positively with body fat and negatively with fat-free mass and strength parameters in HIV-infected patients. Female patients infected with HIV receiving highly active antiretroviral therapy have higher levels of irisin compared with men in a similar circumstance.

Efeitos do treinamento físico combinado realizado na intensidade do limiar anaeróbio sobre a composição corporal e sistema imune de sujeitos com HIV / Effects of combined physical training performed at anaerobic threshold intensity on the body composition and immune system of subjects with HIV

O objetivo do presente estudo foi avaliar os efeitos do treinamento físico combinado (TC) de 16 semanas sobre a composição corporal e o sistema imune, bem como velocidade e inclinação da esteira rolante obtidos na intensidade do limiar anaeróbio (LAn) em indivíduos com HIV. Participaram do estudo10 indivíduos, sendo 5 homens e 5 mulheres (44,7±8,97 anos; Tempo de Terapia Antirretroviral Altamente Ativa [HAART]: 8,89±6,21 anos; Tempo Portador: 9,14±5,37 anos; Carga Viral: indetectável), os quais foram submetidos a 16 semanas de TC. Os dados foram expressos como média±desvio padrão (p≤0,05). Foram observadas melhoras em relação à massa magra relativa (MMR; %) (Pré: 45,5 [32,8 – 63,0]; Pós: 47,9 [33,7 – 66,3]) e massa magra absoluta (MMA; %) (Pré: 67,0 [55,0 – 75,2]; Pós: 68,8 [56,6 – 75,7]). O índice de massa corporal (IMC; kg/m2 ) não sofreu alteração pós TC (Pré: 24,2 [21,3 – 28,7]; Pós: 23,7 [21,8 – 30,0]). A carga viral permaneceu indetectável, sendo que houve aumento no número delinfócitos T CD4+ (Pré: 529 [426,0 – 900,0]; Pós: 694 [381,0 – 1175,0]). Além disso, houve melhora nosvalores de VO2 (ml.kg.min-1) (Pré: 16,2±4,9; Pós: 21,2±3,2), velocidade (km/h) (Pré: 5,7±0,9; Pós: 6,3±1,0) e inclinação (%) (Pré: 3,8±1,2; Pós: 4,9±1,0) obtidos na intensidade do LAn. Conclui-se que oTC melhorou o VO2 na intensidade do LAn e induziu a aumentos de MMR e de MMA. Finalmente, o TC promoveu aumento no número de linfócitos T CD4+, sem efeito negativo sobre a carga viral. Estes resultados são de extrema importância para a qualidade de vida dos pacientes com HIV.

The aim of the present study was to evaluate the effects of combined physical training (CT) on body composition and immune system, as well as, speed and inclination obtained at the intensity of anaerobic threshold (AT) in subjects with HIV. Ten individuals, 5 men and 5 women, united in a single group (44.7±8.97 years of age; Highly Active Antiretroviral Therapy [HAART] time: 8.89±6.21 years; HIV-Bearer Time: 9.14±5.37 years; Viral Load: undetectable), were subjected to 16 weeks of CT. Data were expressed as mean±standard deviation (p ≤ 0.05). Both relative lean mass (RLM; %) (Pre: 45.5 [32.8-63.0]; Post: 47.9 [33.7-66.3]) and absolute lean mass (ALM; %) (Pre: 67.0[55.0-75.2]; Post: 68.8 [56.6-75.7]) were improved after CT. The body mass index (BMI; kg/m2 ) did not change post-CT (Pre: 24.2 [21.3 – 28.7]; Post: 23.7 [21.8 – 30.0]). The viral load remained undetectable, while the number of CD4+ T lymphocytes was increased (Pre: 529 [426.0-900.0]; Post: 694 [381.0-1175.0]). In addition, VO2(ml.kg.min-1) (Pre: 16.2 ± 4.9; Post: 21.2 ± 3.2), speed (km/h) (Pre: 5.7 ± 0.9; Post: 6.3 ± 1.0) and inclination (%) (Pre: 3.8 ± 1.2; Post: 4.9 ± 1.0), obtained at AT intensity, were improved. It was concluded that CT was able to improve the VO2 at the intensity of AT and induced increases in RLM and ALM. Finally, the CT increased the number of CD4 + T lymphocytes, with no negative effect on the viralload. These results are extremely important for the quality of life of patients with HIV.