Alteration of Pressure-Induced Vasodilation in Aging and Diabetes, a Neuro-Vascular Damage

Abstract

Skin is constantly subjected to pressure at different levels. Pressure-induced vasodilation (PIV) is one of the response mechanisms to low pressure that maintains the homeostasis of the skin. PIV results from the interaction of primary afferent nerves and vascular endothelium of skin vessels. Thanks to this cutaneous neuro-vascular interaction, the cutaneous blood flow increase allows the maintenance of an optimal level of oxygenation and minimizes the lack of vascularization of the skin tissue under low pressure. It seems to be associated with the cutaneous protection mechanisms to prevent pressure ulcers. In some contexts, where microangiopathy and neuropathy can occur, such as aging and diabetes, PIV is impaired, leading to a dramatic early decrease in local skin blood flow when low pressure is applied. In aging, PIV alteration is due to endothelial dysfunction, essentially from an alteration of the nitric oxide pathway. In the inflamm-aging context, oxidative stress increases leading to endothelial cell and nerve damages. An age-related sensory neuropathy will exacerbate the alteration of PIV during the aging process. In diabetes, non-controlled hyperglycaemia leads to an increase in several pathological biochemical pathways that involve oxidative stress and can affect PIV. Sorbinil, alagebrium and alpha-lipoic acid are able individually to restore PIV through a possible oxidative stress reduction. Candesartan, an angiotensin II type 1 receptor blocker, is also able to restore PIV and prevent pressure ulcer formation. The possibility of preventing pressure ulcer associated to diabetes and/or aging with the restoration of PIV seems to be a promising research path.

A Synoptic Overview of Neurovascular Interactions in the Foot

“…This response is observed during local application of progressive pressure over time. It is known to be a transient increase in cutaneous blood flow initially before it decreases in response to the stimuli induced by the pressure strain (84)(85)(86)(87). This assessment once again shows the relationship between small fiber nerve function and microcirculation.…”

“…Research suggests that Pressure-Induced Vasodilation (PIV) is one of the cutaneous microcirculatory reactive mechanisms to low pressure (84). PIV works through a vascular and neuronal mechanism (84,85). It results from the interaction of primary afferent nerves and vascular endothelium of skin vessels.…”

“…A recent study demonstrated that the cutaneous vasodilation in response to pressure is decreased in people with DFU in comparison to people without (97). Moreover, these responses are known to be impaired in the cohort of the aging population (84). Thus, the physiological process of aging and progression of pathological conditions of diabetes may worsen the neurovascular functions making certain groups of people (elderly population with diabetes) more vulnerable to complications such as ulcers.…”

Vieillissement et intégrité de la peau

“…Cette situation, à laquelle nous sommes adaptés, est à l'origine de lésions ischémiques induites par la pression vis-à-vis desquelles la peau est protégée [26]. Cette capacité de défense de la peau repose sur des mécanismes neuro-vasculaires dépendant de l'endothélium [27]. Au cours du vieillissement, la peau devient fragile et la dys- Globalement, la production du NO diminue via la baisse de biodisponibilité de la NO synthase endothéliale (eNOS), de son précurseur (L-arginine) et de co-facteurs, tels que la tétrahydrobioptérine (BH4).…”

The risk of surgery-related pressure ulcer in diabetics: A systematic review and meta-analysis

“…Also, other factors including senility, diabetes, smoking, peripheral vascular disease, malnutrition, low weight, and Hypoalbuminemia, and Hypoproteinemia are contributed to the occurrence of these ulcers [ [5] , [6] , [7] ]. Among these contribution factors, diabetes is thought by some clinicians to be the most important factor as it is one of the morbidity factors in patients undergoing surgery which can reduce blood flow in epidermal layers then damages the vascular structure, therefore increase the risk of occurrence pressure ulcer [ 7 , 8 ]. These published reports have varied by incidence, type of surgery, and risk factors, among other reasons [ 3 ].…”