Hypoxia of diabetic feet with abnormal arterial blood flow

Abstract

Necrotic ulcers of the feet are a dangerous complication of the diabetic foot syndrome. Besides peripheral vascular disease (PVD) peripheral neuropathy is an important factor in the pathogenesis of necroses. We examined whether the reserve of circulation during reactive hyperemia at the feet of patients with type I diabetes mellitus with abnormal blood flow (n = 17) is decreased compared with diabetic (n = 14) and nondiabetic (n = 20) controls. Further we analyzed whether there is a correlation with the oxygen supply of the foot. PVD was excluded by clinical check-up, oscillography, and Doppler ultrasound. The reserve of circulation of the foot was measured during reactive hyperemia and oxygen supply of the foot by oximetry. Abnormal blood flow of the foot was diagnosed by the pulsation index. On examination it was found that the reserve of circulation of diabetic feet with abnormal blood flow is about 52% less than in diabetic and about 50% less than in nondiabetic controls (P < or = 0.005). The decreased reserve of circulation correlates with the oxygen supply of the feet; this is about 21% less compared to diabetic feet with normal blood flow and about 16% less in comparison to nondiabetic feet. The present study shows that diabetic feet suffer from disturbed circulation although there is no evidence of PVD. This disturbed circulation is correlated with a decreased oxygen supply of the feet. Hypoxia during strain could be of great importance in the pathogenesis and treatment of necrotic ulcers of diabetic feet.

Macrophage responses to hypoxia: relevance to disease mechanisms

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HIF-1α expression regulates the bactericidal capacity of phagocytes

“…The effectiveness of myeloid cells in innate defense reflects their capacity to function in low-oxygen environments. Whereas in healthy tissues oxygen tension is generally 20-70 mm Hg (i.e., 2.5-9% oxygen), much lower levels (< 1% oxygen) have been described in wounds and necrotic tissue foci (1)(2)(3).…”

Impaired respiration elicits SrrAB-dependent programmed cell lysis and biofilm formation in Staphylococcus aureus

“…Oxygen concentrations also vary between healthy and infected or necrotic tissues, as well as in wounds, where concentrations are estimated to be below 1% (hypoxic) or anoxic (Carreau et al, 2011; Vogelberg and König, 1993; Arnold et al, 1987). A recent study found that S. aureus infections in skeletal tissues (osteomyelitis) cause an ~3 fold decrease in oxygen concentrations resulting in increasing hypoxia as infection proceeds (Wilde et al, 2015).…”