The Role of Cutaneous Microcirculatory Responses in Tissue Injury, Inflammation and Repair at the Foot in Diabetes

Abstract

Diabetic foot syndrome is one of the most costly complications of diabetes. Damage to the
soft tissue structure is one of the primary causes of diabetic foot ulcers and most of the
current literature focuses on factors such as neuropathy and excessive load. Although the
role of blood supply has been reported in the context of macro-circulation, soft tissue
damage and its healing in the context of skin microcirculation have not been adequately
investigated. Previous research suggested that certain microcirculatory responses protect
the skin and their impairment may contribute to increased risk for occlusive and ischemic
injuries to the foot. The purpose of this narrative review was to explore and establish the
possible link between impairment in skin perfusion and the chain of events that leads to
ulceration, considering the interaction with other more established ulceration factors. This
review highlights some of the key skin microcirculatory functions in response to various
stimuli. The microcirculatory responses observed in the form of altered skin blood flow are
divided into three categories based on the type of stimuli including occlusion, pressure and
temperature. Studies on the three categories were reviewed including: the microcirculatory
response to occlusive ischemia or Post-Occlusive Reactive Hyperaemia (PORH); the
microcirculatory response to locally applied pressure such as Pressure-Induced
Vasodilation (PIV); and the interplay between microcirculation and skin temperature
and the microcirculatory responses to thermal stimuli such as reduced/increased
blood flow due to cooling/heating. This review highlights how microcirculatory
responses protect the skin and the plantar soft tissues and their plausible dysfunction
in people with diabetes. Whilst discussing the link between impairment in skin perfusion as
a result of altered microcirculatory response, the review describes the chain of events that
leads to ulceration. A thorough understanding of the microcirculatory function and its
impaired reactive mechanisms is provided, which allows an understanding of the
interaction between functional disturbances of microcirculation and other more
established factors for foot ulceration.