Effects of Supervised Exercise Training on Erythrocyte Deformability in Hemodialysis Patients

Asia University63 enrolled

Overview

This study evaluated red blood cell function and aerobic capacity in adults receiving maintenance hemodialysis and in healthy reference participants. Participants receiving hemodialysis were included in either a supervised exercise training group or a usual-care group. The supervised exercise program combined resistance and aerobic exercise performed before hemodialysis. Participants in the exercise group completed repeated assessments across a non-exercise observation period, exercise training, and post-training follow-up. The usual-care group continued usual care without supervised exercise training, and healthy participants served as a reference group. Assessments included cardiopulmonary exercise testing and blood sampling to evaluate aerobic capacity, red blood cell deformability, and red blood cell characteristics related to membrane function, cell shape, oxidative stress, and calcium-related responses.

This prospective study included adults receiving maintenance hemodialysis and healthy reference participants. Participants receiving hemodialysis were included in a supervised exercise training group or a usual-care group. Healthy participants underwent reference assessments without exercise intervention. Participants in the supervised exercise group first completed a non-exercise observation period and subsequently undertook supervised pre-dialysis exercise training combining resistance and aerobic exercise. Training was performed two to three times per week, with a target of 72 supervised sessions. Exercise sessions were performed approximately 1 to 2 hours before hemodialysis. Aerobic exercise was performed using a cycle ergometer, recumbent stepper, or treadmill, with exercise intensity prescribed according to cardiopulmonary exercise testing. Resistance exercises targeted the upper limbs, lower limbs, and trunk. Blood pressure and electrocardiographic monitoring were performed during exercise sessions. Participants in the usual-care group continued their usual care without supervised exercise training. Longitudinal assessments in the exercise group were conducted at study entry, after the non-exercise observation period, during training, after completion of training, and after cessation of training. Assessments included cardiopulmonary exercise testing and blood sampling. Red blood cell analyses included osmotic and mechanical deformability and selected cellular characteristics related to membrane function, cell shape, oxidative stress, and intracellular calcium responses. Healthy participants provided reference data for corresponding physiological and erythrocyte measurements.

Study Type

Interventions

Supervised Exercise TrainingBEHAVIORAL

Supervised pre-dialysis exercise training combining aerobic and resistance exercise was performed two to three times per week. Each session included aerobic exercise using a cycle ergometer, recumbent stepper, or treadmill, together with resistance exercises targeting the upper limbs, lower limbs, and trunk. Exercise intensity was prescribed according to cardiopulmonary exercise testing and adjusted according to participant tolerance and clinical status. Training was conducted approximately 1 to 2 hours before hemodialysis, with a target of 72 supervised exercise sessions.

Eligibility

Sex: ALLMin age: 20 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Age 20 years or older * For participants with end-stage renal disease: maintenance hemodialysis for more than 6 months, clinically stable during the previous 3 months, stable medical treatment for at least 6 weeks, nephrologist approval for participation, and Kt/V \>1.2. * For healthy reference participants: no history of kidney disease. * Willingness to provide written informed consent. Exclusion Criteria: * Hyperkalemia within the previous 3 months. * Orthopedic disease, muscle weakness, or other medical, physiological, or psychological conditions preventing exercise training or exercise testing. * Pregnancy or planned pregnancy within 1 year. * Implanted cardiac devices that prevented achievement of the heart rate required for exercise training. * Cardiovascular, metabolic, or other clinical contraindications to exercise testing or training.

Outcomes

Primary Outcomes

Change in Maximal Erythrocyte Elongation Index (EImax)

Maximal erythrocyte elongation index (EImax) was derived from ektacytometry measurements obtained across increasing shear stress.

Time frame: Baseline (study entry); 3 months after baseline (pre-training); mid-training after 36 supervised exercise sessions; end of training after 72 supervised exercise sessions; and 3 months after training cessation

Change in Shear Stress at One-Half Maximal Erythrocyte Deformation (SS1/2)

The shear stress required to achieve one-half of maximal erythrocyte deformation (SS1/2) was derived from ektacytometry measurements across increasing shear stress.

Change in Hypertonic Osmolality at 50% of Maximal Elongation Index (Ohyper)

Ohyper was assessed by osmotic-gradient ektacytometry and defined as the hypertonic osmolality at 50% of maximal erythrocyte elongation index.

Change in Osmolality at Maximal Elongation Index (Omax)

Omax was assessed by osmotic-gradient ektacytometry and defined as the osmolality at maximal erythrocyte elongation index.

Change in Osmoscan Area Under the Elongation Index-Osmolality Curve

Osmoscan area was assessed by osmotic-gradient ektacytometry and defined as the area under the erythrocyte elongation index-osmolality curve.

Secondary Outcomes

Change in Peak Oxygen Uptake (Peak VO₂/kg) Assessed by Cardiopulmonary Exercise Testing

Peak oxygen uptake normalized to body mass (mL/kg/min) was measured during symptom-limited cardiopulmonary exercise testing.

Time frame: Baseline; 3 months after baseline; after 36 supervised exercise sessions (mid-training); after 72 supervised exercise sessions (end of training); and 3 months after training cessation

Change in Erythrocyte Cellular Characteristics

Red blood cell cellular and membrane-related characteristics were assessed using laboratory-based methods.

Change in Gardos-Related Erythrocyte Deformability Response

Gardos-related erythrocyte deformability response was assessed by ektacytometry under calcium-dependent challenge conditions.

Change in Erythrocyte Intracellular Calcium Response to Oxidative Stress

Erythrocyte intracellular calcium response to oxidative stress was assessed using Fluo-4 fluorescence and flow cytometry.

Change in Erythrocyte Side-Scatter Response to Oxidative Stress

Erythrocyte side-scatter response to oxidative stress was assessed by flow cytometry.