Among others, dysregulated inflammation has been identified in the process of diabetic wound healing. In fact, even before wounding a proinflammatory baseline state is found in diabetic patients and animal models.The chronic proinflammatory environment in diabetic wounds prevents progression to the proliferative phase of wound healing, and impairs key processes of tissue repair such as angiogenesis, extracellular matrix (ECM) remodelling and re-epithelialization.
Land snails and their mucus were used to treat pain related to burns, abscesses, and other wounds in antiquity by Hippocrates and Pliny.
Inspired by the age-old therapy, Prof WU Mingyi and his team at Kunming Institute of Botany, Chinese Academy of Sciences (KIB/CAS) identified a natural biological adhesive from snail secretion, evaluated its in vitro adhesion properties and studied its in vivo effects on wound healing.
The results entitled “A natural biological adhesive from snail mucus for wound repair” has been published in the Journal of Nature Communications.
Researchers found that the natural biomaterial (d-SMG) consists of 30–50% protein and 10–16% sulfated glycosaminoglycan (GAG). The composition of d-SMG is similar to that of ECM which is composed of fibrous proteins and polysaccharides, and provides mechanical support for cell growth and regulates cell behavior.
d-SMG exhibited better adhesion performance in wet tissue than the clinical fibrin glue in both vitro and vivo studies. The natural GAG-protein-based gel provides a moist tissue micro environment with reduced inflammation that is in favor of tissue regeneration.
In vivo study showed that d-SMG promoted skin wound healing in both normal and diabetic rat models. It improved the angiogenesis, granulation tissue neogenesis, collagen deposition, and epidermal regeneration in the wound bed.
For diabetic wound, mechanism study showed that both d-SMG dressing and its active ingredient s-GAG promoted the polarization of macrophages towards the anti-inflammatory M2 phenotype by upregulating STAT3 phosphorylation, which may contribute to the transition of wound healing process from inflammation to proliferation.
Thus accelerating wound healing. Moreover, d-SMG contains a high content of heparin-like GAG which also can bind the inflammatory cytokines (TNF-α, IL-6, IL-8, and IP-10) with high affinity.
Therefore, d-SMG reduced the levels of inflammatory cytokines (TNF-α, IFN-γ and IL-6) in wound tissues possibly by both regulating macrophage polarization and capturing inflammatory cytokines.
In this study, the term found a natural glycosaminoglycan-based snail mucus gel can seal skin wound and promote diabetic wound healing.
These findings provide theoretical and material insights into developing bioactive dressings and bioengineered scaffolds for wound healing.
In the future, they hope to apply the bioadhesive as a novel treatment for DFU. These Chinese scientists aim to develop more effective drugs or wound dressings for clinical need by targeting the pathogenesis of DFU.
Fig 1. Schematic interpretation of the mechanism of d-SMG in wound healing.
a Formation of double-network snail-mucus hydrogel. b A possible tissue adhesion mechanism of d-SMG. C The postulated mechanism of d-SMG in accelerating wound healing, including hemostasis, anti-inflammation, and angiogenesis.