Proteome analysis reveals antiangiogenic environments in chronic wounds of diabetes mellitus type 2 patients

Abstract

In contrast to normal healing wounds, chronic wounds commonly show disturbances in proteins regulating wound healing processes, particularly those involved in cell proliferation and protein degradation. Multidimensional protein identification technology MS/MS was conducted to investigate and compare the protein composition of chronic diabetic foot exudates to exudates from split-skin donor sites of burn victims otherwise healthy. Spectral counting revealed 188 proteins differentially expressed (more than twofold and p-value <0.05) in chronic wounds. Most were involved in biological processes including inflammation, angiogenesis, and cell mortality. Increased expression of the inflammatory response stimulating S100 proteins, predominantly S100A8 and S100A9 (almost tenfold), was identified. Matrix metalloproteinases (MMPs) MMP1, MMP2, and MMP8 were identified to be elevated in chronic wounds with significant impact on collagen degradation and tissue destruction. Further, proteins with antiangiogenic properties were found at higher expression levels in chronic wounds. Reduced angiogenesis leads to drastic shortage in nutrition supply and causes increased cell death, demonstrated by Annexin A5 exclusively found in chronic wound exudates. However, excessive nucleic and cytosolic material infers cell death occurring not only by apoptosis but also by necrosis. In conclusion, mass spectrometric investigation of exudates from chronic wounds demonstrated dramatic impairment in wound repair with excessive inflammation, antiangiogenic environment, and accelerated cell death.

Pathogenesis of wound healing disorders in the elderly

“…Exudates from diabetic wounds studied by mass spectrometry revealed an increased expression of proteins with antiangiogenic properties [ 57 ] . Disturbed angiogenesis leads to hypoxia and subsequently cell death due to apoptosis or necrosis [ 57 ] .…”

“…Roughly 15-25 % of diabetics will develop a diabetic foot ulcer, which represents one of the most common complications, and accounts for more than 80 % of all lower leg amputations [ 56 ] . Exudates from diabetic wounds studied by mass spectrometry revealed an increased expression of proteins with antiangiogenic properties [ 57 ] . Disturbed angiogenesis leads to hypoxia and subsequently cell death due to apoptosis or necrosis [ 57 ] .…”

Activity of mesenchymal stem cells in therapies for chronic skin wound healing

“…However, in the case of chronic wounds, the normally-ischemic wound environment becomes even harsher, with excessive inflammation 100 and an environment not conducive to angiogenesis compared with normal wounds. 81 Therefore, a significant barrier to successful use of MSCs in any potential cell therapy has been post-implant cell survival in a variety of ischemic injury models. Past studies have shown marginal MSC preservation in various models including cardiac infarct 101 or cerebral injury, 102 but still MSC use in any of these models is limited by MSC death due to the harsh wound environment.…”

“…Chronic wounds are often subject to antiangiogenic conditions, including reduced growth factor production as a result of increased MMP production in the wound bed, as outlined by Krisp et al recently in a global secretome analysis of wound exudates. 81 MSCs naturally produce a variety of pro-angiogenic factors following recruitment to the wound bed that stimulate endothelial cell proliferation and tube formation in the wound bed, most notably VEGF, a potent stimulator for angiogenesis that is regulated by IL-6 and TGF-α in the wound bed. 82 Though it has been shown that exogenous VEGF application to wounds can stimulate angiogenesis, 83 MSCs used in cell therapeutics also have been shown to stimulate EC recruitment and wound healing via VEGF secretion 33,75 or via pre-differentiation into angiogenic precursors.…”

The molecular signature of impaired diabetic wound healing identifies serpinB3 as a healing biomarker

“…Such approaches are used to generate hypotheses that need to be verified in animal models and in humans [9]. So far, proteomics has been rarely used to discover new aspects of the delayed diabetic wound healing process, and the resulting pathways have never been validated [10][11][12]. Furthermore, cross-sectional comparisons of diabetic vs non-diabetic wound tissues have been biased by patients' differences and underlying conditions [10,11].…”