Acute and Chronic Wound Fluid Inversely Influence Wound Healing in an in-Vitro 3D Wound Model

Abstract

If a wound progressively heals or the healing process is impaired is basically influenced by the surrounding milieu. This is reflected by the wound fluid. Its specific composition triggers the migration, proliferation and differentiation of dermal and epidermal cells which so far was not sufficiently examined in 2D cell culture models. The influence of the different wound entities was analyzed on a newly implemented three dimensional in-vitro model, which improved the transferability to the in-vivo situation. The influence of pooled wound fluids from patients suffering from acute or chronic wounds were investigated within a time period of 10 days after wound application. Histological and immunohistochemical analyses were performed addressing the impact of AWF and CWF on regeneration, such as cell proliferation, fibroblast activity and cell migration. AWF slightly stimulated fibroblast migration while CWF inhibited their activation and migration. The CXCR4-immunopositive population was continuously decreased compared to the control and AWF treatment.The expression of FAP was enhanced under AWF and medium. In keratinocytes CWF massively stimulated cell proliferation initiating on day six after injury. The presence of 10% CWF inhibited fibroblast activation and migration and induced the degradation of the collagen matrix. Keratinocytes were stimulated to proliferate, resulting in healing inhibiting hyperplasia. Transferred to human wounds, no effective wound closure would be achieved because of the de-regulation of pro-proliferative and migration-stimulating factors and a degraded extracellular matrix.This newly implemented 3D study model represents a novel appropriate in-vitro system for studying healing mechanisms and potential therapeutic applications.

Low mortality oxidative stress murine chronic wound model

“…54 Cellular hyperproliferation was seen in both groups treated with antioxidant enzyme inhibitors, a phenomenon previously described in chronic wounds. [55][56][57] Specifically, application of wound fluid from chronic wounds to in vitro wounds has been shown to induce massive proliferation of keratinocytes. 56 A "chronic wound associated phenotype" in chronic ulcers, characterized by cellular overproliferation and overexpression of the marker Ki-67 has also been described.…”

“…55 Clinically, chronic wounds display keratinocyte hyperproliferation and overgrowth of the wound margin, resulting in a raised borders and a pocket-like wound, which is more difficult to clean and more likely to harbor infection. 56 The model was also used to test the application of a commonly used scaffold. Despite the poor engraftment, it should be noted that on day 10, the group treated with the scaffold showed a higher level of microvasculature Emerging technologies, pharmacology and therapeutics maturation than the Chronic diabetic group.…”

“… 55–57 Specifically, application of wound fluid from chronic wounds to in vitro wounds has been shown to induce massive proliferation of keratinocytes. 56 A “chronic wound associated phenotype” in chronic ulcers, characterized by cellular overproliferation and overexpression of the marker Ki-67 has also been described. 55 Clinically, chronic wounds display keratinocyte hyperproliferation and overgrowth of the wound margin, resulting in a raised borders and a pocket-like wound, which is more difficult to clean and more likely to harbor infection.…”

Bioengineered Platforms for Chronic Wound Infection Studies: How Can We Make Them More Human-Relevant?

“…In addition to complex biological interactions, the chronic wound infection bed is subject to nutrient factors and chemical gradients, which influence several critical functions. Chronic wound fluid is an important factor in the wound milieu (Trengove et al, 1996;Cutting, 2003;Widgerow, 2011;Manuela et al, 2017), reflecting the processes and functions that contribute to and perpetuate the chronic wound state. In addition to a unique signature of proteins, growth factors and proinflammatory cytokines, chronic wound fluid is known to contain high levels of matrix metalloproteinases (MMPs), which impact a range of functions related to the chronic wound state (Wysocki et al, 1993;Jindatanmanusan et al, 2018).…”

“…Wound fluid represents the composite wound milieu and reflects critical processes and functions that contributing to the chronic wound state (Trengove et al, 1996;Cutting, 2003;Widgerow, 2011;Manuela et al, 2017). The composition and characteristics of wound fluid, including nutrient and biochemical factors, impact microbial growth and proliferation in the wound bed.…”