Biomarkers for the evaluation of immunological properties during the shikoku walking pilgrimage

Abstract

It is important to determine the immunological properties for the maintenance of health. We chose the Shikoku Walking Pilgrimage to assess the proper biomarkers for the evaluation of immunological properties. We examined whether the Shikoku Walking Pilgrimage could have a positive effect on the mental and physical health of walking participants by using several biomarkers proposed by our laboratory. Twelve non-randomized healthy male volunteers including 3 twice attendees walked the Shikoku Walking Pilgrimage distance of 58.9 km over 3 days. Plasma, serum, urine, and saliva were collected from the volunteers during the pilgrimage and at 1 week before and after it. Immunological biomarkers, including lipid metabolism, oxidative stress, immune function, and catecholamines, were measured. Additionally, mood state scores, alertness, autonomic nervous system activity, and body motion levels during sleep were assessed. A significant decrease was observed in the subjective tension-anxiety levels and in the concentrations of serum low-density lipoprotein cholesterol, plasma hydroxyoctadecadienoic acid (HODE), and urine adrenaline during the pilgrimage as compared to the values of these parameters before the participants embarked on the pilgrimage. The serum levels of brain-derived neurotrophic factor (BDNF) were significantly increased 1 week after the pilgrimage relative to those assessed previously. No significant differences in subjective fatigue and the flicker perception threshold were observed. These results suggest that the Shikoku Walking Pilgrimage can exert a positive effect on mental and physical health as particularly shown in the reduction of tensionanxiety and oxidative stress without the accompaniment of fatigue. HODE correlated significantly with typical immunological marker natural killer cell activity and immunoglobulin G. This suggests that there are promising biomarkers such as HODE, NK activity, BDNF, LDL-c, and IgG for assessing the immunological properties.