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Osteoarthritis of the knee (kOA) is a disease that mainly affects the elderly and can lead to major physical and functional limitations. However, the specific effects of walking, particularly on the immune system, are unknown. Therefore, this study aimed to analyze the effect of 12 weeks of walking (3×/week) on the leukocyte profile and quality of life (QL) of elderly women with kOA. Sixteen women (age: 67±4 years, body mass index: 28.07±4.16 kg/m2) participated in a walking program. The variables were assessed before and after 12 weeks of training with a progressively longer duration (30-55 min) and higher intensity (72-82% of HRmax determined using a graded incremental treadmill test). The QL was assessed using the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36), and blood samples were collected for analysis with a cell counter and the San Fac flow cytometer. Walking training resulted in a 47% enhancement of the self-reported QL (P<0.05) and a 21% increase in the VO2max (P<0.0001) in elderly women with kOA. Furthermore, there was a reduction in CD4+ cells (pre=46.59±7%, post=44.58±9%, P=0.0189) and a higher fluorescence intensity for CD18+CD4+ (pre=45.30±10, post=64.27±33, P=0.0256) and CD18+CD8+ (pre=64.2±27, post=85.02±35, P=0.0130). In conclusion, the walking program stimulated leukocyte production, which may be related to the immunomodulatory effect of exercise. Walking also led to improvements in the QL and physical performance in elderly women with kOA.

Knee osteoarthritis is a common disease in the elderly population worldwide. The alleviation of the symptoms associated with this disease can be achieved with physical exercise that induces a cascade of molecular and cellular processes. Of the neurotrophins, brain-derived neurotrophic factor (BDNF) appears to be the most affected by physical activity. Moreover, BDNF seems to have a negative modulatory role in inflammation, and its production by skeletal muscle cells or by cells of the immune system drives the immunoprotective role of physical activity in situations of chronic inflammation. Therefore, the aim of this study was to evaluate plasma BDNF concentrations in elderly individuals presenting with knee osteoarthritis. To accomplish this, sixteen volunteers (mean age 67 ± 4.41 years) presenting with clinically and radiographically diagnosed knee osteoarthritis were evaluated during acute exercise (1 session of 20 min on a treadmill) and after chronic exercise (12 weeks of aerobic training, consisting of a 50-min walk 3 times per week). Additionally, both a functional assessment (during a 6-min walk) and a pain perception assessment were performed at the start and at the end of physical exercises (training). The plasma BDNF concentrations were measured by ELISA. For the population studied, acute exercise increased the levels of BDNF only before the 12-week training period (p < 0.001). Moreover, the training augmented the plasma concentrations of BDNF (p < 0.0001) and improved clinical parameters (functional p < 0.001; pain perception p < 0.01).

The aim of this study was to investigate the effect of adding whole-body vibration (WBV; frequency = 35 to 40 Hz; amplitude = 4 mm) to squat training on the T-cell proliferative response of elderly patients with osteoarthritis (OA) of the knee. This study was a randomized controlled trial in which the selected variables were assessed before and after 12 weeks of training. Twenty-six subjects (72 ± 5 years of age) were divided into three groups: 1) squat training with WBV (WBV, N = 8); 2) squat training without WBV (N = 10), and 3) a control group (N = 8). Women who were ≥60 years of age and had been diagnosed with OA in at least one knee were eligible. The intervention consisted of 12 uninterrupted weeks of squatting exercise training performed 3 times/week. Peripheral blood mononuclear cells were obtained from peripheral blood collected before and after training. The proliferation of TCD4+ and TCD8+ cells was evaluated by flow cytometry measuring the carboxyfluorescein succinimidyl ester fluorescence decay before and after the intervention (∆). The proliferative response of TCD4+ cells (P = 0.02, effect size = 1.0) showed a significant decrease (23%) in the WBV group compared to the control group, while there was no difference between groups regarding the proliferative response of TCD8+ cells (P = 0.12, effect size = 2.23). The data suggest that the addition of WBV to squat exercise training might modulate T-cell-mediated immunity, minimizing or slowing disease progression in elderly patients with OA of the knee.

The aim of this study was to evaluate levels of interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), and soluble forms of the TNF-α receptor (sTNFR1 and sTNFR2) from plasma taken from the peripheral blood of elderly individuals presenting with osteoarthritis (OA) of the knee. These patients underwent aerobic treatment through the use of physical exercises. The study consisted of a longitudinal analysis of older individuals presenting clinical and radiographic diagnosis of knee OA that were submitted to 12 weeks of aerobic treatment. The individuals were evaluated during acute exercise or after chronic exercise. During acute exercise (walking slowly on the mat), blood samples of the patients were collected before, immediately after, and 30 min following the end of training. After chronic exercise (aerobic walking training, three times/week for 12 weeks), patient blood samples were obtained for comparison. Additionally, clinical and functional assessments (WOMAC test and 6-min walk) were performed at the end of all physical exercises. Plasma concentrations of cytokines and soluble receptors were measured by ELISA. Aerobic training increased the plasma concentration of sTNR1; however, it decreased the plasma concentration of sTNFR2, when compared with levels of resting patients. Acute exercise differentially affects the levels of sTNFR1 dependent on when the samples were taken, before and after aerobic training. However, the levels of sTNFR2 were not affected by training. For the population studied, we observed differences in the levels of sTNFR1 and sTNFR2 following acute and chronic exercise. Other additional factors, like the level of inactivity of the individual and the type of physical exercise that patients are exposed to, need to be considered as well. The variation in the levels of soluble receptors correlated with functional improvement; however, the inflammatory osteoarthritis markers (IL-6 and TNF-α) were unaffected by the walking exercises.