Researchers found a slight increase in cross-sectional area (CSA) and myonuclear content in type 1 muscle fibers after an exercise training program in patients with sickle cell disease (SCD) and published their results in the Journal of Histochemistry & Cytochemistry.

They also reported that the skeletal muscle satellite cell pool was unchanged in type 1 and was slightly decreased in type 2 fibers compared with patients who did not participate in the training program.

“The present study was the first clinical randomized controlled trial evaluating skeletal muscle [satellite cells] in adult
SCD patients without severe chronic complications and their responses to an 8-week moderate-intensity
endurance training program,” the authors said.

“The training program did not induce muscle damage, as no necrotic fibers were detected in patients before or after the training program, reinforcing previous findings suggesting that this type of training seems to be safe and could be considered as a novel therapeutic strategy in SCD.”

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The research team conducted an 8-week, moderate-intensity training program with 15 patients with SCD and 18 control patients who did not participate in the training. Under the supervision of a physician, the patients in the training group completed 24 sessions of endurance training, 3x per week for 8 weeks.

To determine changes in muscle fibers, biopsies of the vastus lateralis muscle were obtained pre- and postintervention. The overall mean CSA of the muscle fibers in both groups was unchanged after the intervention. However, the CSA of the type 1 muscle fibers in the training group increased slightly and decreased slightly in the nontraining group.

After the intervention, there was a significant reduction in the satellite cell pool in type 2 fibers compared with type 2 fibers in the nontraining group.

The authors suspect that satellite cells contributed to the slight hypertrophy in type 1 fibers in the training group, but the limited response of the fibers was likely due to the short duration and low intensity of the exercise sessions. Given that no necrotic fibers were observed in any patient before or after the training, the team concludes that the training program was safe for the participants.


Januel L, Merlet AN, He Z, et al. Skeletal muscle satellite cells in sickle cell disease patients and their responses to a moderate-intensity endurance exercise training program. J Histochem Cytochem. Published online May 31, 2022. doi:10.1369/00221554221103905