Physical Fitness/Training and Inflammatory Immune Responses in Patients With End-stage Renal Disease

In Taiwan, there are more than 90 thousand patients with end-stage renal disease (ESRD) receiving hemodialysis (HD) island-wide. The leading two causes of death are cardiovascular diseases and sepsis. Though evidence is clear that exercise training in this population is beneficial to fitness、quality of life、morbidity, it is seriously underuse. Poor physical fitness is known to associate with high-leveled systemic inflammation and immune dysregulation but the detailed relationship remains unclear in the ESRD population. Moreover, though exercise improves low physical fitness, available research concerning its effect on the pro-/anti-inflammatory immune response is scarce. In the current proposal, physical fitness is classified into cardiopulmonary fitness and muscle fitness. Muscle fitness is further divided into three domains: strength, mass, and oxidative capacity. The 3-year proposal plan to recruit 90 patients with ESRD who receive regular HD for more than 6 months. Every participant will go through 3 phases：control phase、training phase and the maintenance phase (within-subject design). In the control phase, no exercise education or training will be given to the participants. In the training phase, the participants will receive in-hospital supervised exercise training prior to HD. The training program will last 6 months and about 60 training sessions in total. The training protocol contains cyclic aerobic training in moderate-intensity and high-intensity interval training plus isokinetic resistance training. In the following maintenance phase, home-based exercise training will be educated. The control and maintenance phases are 1-2 and 3 months respectively in duration. Before and after each phase and in the middle of the training phase (5-time points totally), every participant will receive a thorough evaluation as follows: CPET with noninvasive cardiac output monitor, isokinetic strength testing, handgrip strength, muscle oxidative capacity, body composition by dual-energy x-ray absorptiometry, Chinese Kidney Disease and Quality of Life questionnaire and international physical activity questionnaire and blood sampling for pro-/anti-inflammatory markers, including chemokine, cytokine, immune cells, and immuno-regulatory microRNAs, etc. The hypothesis of the proposal is as follows. (I) When cardiopulmonary fitness/muscle fitness drops to a certain level, the inflammatory immune response will rise. The proposal aims to find the best biomarkers and their cut-off points among the various indicators of cardiopulmonary and muscle fitness that reflect immune dysregulation. (II) Other than physical fitness, cyclic aerobic and resistance training improves pro-/anti-inflammatory immune dysregulation. Additionally, three months after cessation of training, a thorough assessment will be performed to examine whether a healthy lifestyle behavior modification has been achieved and whether the beneficial effect of physical fitness and immune regulation induced by the training program is maintained. The goal of each year is as follows. FIRST year: To explore the relationship between cardiopulmonary fitness and pro-/anti-inflammatory immune response in ESRD patients under HD; SECOND year: To explore the relationship between muscle fitness and pro-/anti-inflammatory immune response; THIRD year: To evaluate the effects of cyclic aerobic and resistance training on physical fitness and pro-/anti-inflammatory immunomodulation in ESRD patients under HD.