Dynamic microcirculation characteristics of plantar skin in response to life-like pressure in diabetes patients

Diabetic foot ulcer (DFU) is a severe complication of diabetes associated with high mortality. Elevated plantar pressure and impaired microcirculation are considered as primary contributions to DFU. The International Working Group of Diabetic Foot (IWGDF) has recommended an increase in the level of walking‐related weight‐bearing daily activity by an extra 1000 steps/day, but has not provided specific exercise prescription due to limited data on the relationship between pressure and plantar microcirculation. In this study, we aimed to figure out the influence of cyclic life-like pressure on plantar DFU formation from microcirculation perspective. 20 healthy young subjects, 20 healthy middle-aged and elderly subjects, and 20 diabetes patients were recruited. A novel technique was developed to measure real-time skin blood flow (SBF) under cyclic life-like plantar pressure stimulus at plantar 1st metatarsal head. The exerted plantar force was adjusted from 10N (127.3 kPa) to 40N (509.3 kPa), increasing in an increment of 5N (63.7 kPa). Post-load SBF was measured for comparison after each level of pressure. We found all levels of cyclic pressure significantly increased plantar immediate-load and post-load SBF. Furthermore, a pressure threshold emerged at which the increasing magnitude of immediate-load SBF began to diminish. This altered microcirculatory response may serve as a valuable marker for identifying DFU risk and inform precise exercise prescriptions for patients with diabetes.