IGF-1 inhibits inflammation and accelerates angiogenesis via Ras/PI3K/IKK/NF-κB signaling pathways to promote wound healing

Exogenous insulin-like growth factor-1 (IGF-1) has been reported to promote wound healing through regulation of vascular endothelial cells (VECs). Despite the existing studies of IGF-1 on VEC and its role in angiogenesis, the mechanisms regarding anti-inflammatory and angiogenetic effects of IGF-1 remain unclear. In this study, we investigated the wound-healing process and the related signaling pathway of IGF-1 using an inflammation model induced by IFN-γ. The results demonstrated that IGF-1 can increase cell proliferation, suppress inflammation in VECs, and promote angiogenesis. In vivo studies further confirmed that IGF-1 can reduce inflammation, enhance vascular regeneration, and improve re-epithelialization and collagen deposition in acute wounds. Importantly, the Ras/PI3K/IKK/NF-κB signaling pathways was identified as the mechanisms through which IGF-1 exerts its anti-inflammatory and pro-angiogenic effects. These findings contribute to the understanding of IGF-1's role in wound healing and may have implications for the development of new wound treatment approaches.

A European randomised controlled trial for venous leg ulcers: a mathematical model analysis

OBJECTIVE

Mathematical models have the potential to provide valuable insights into complex, biochemical and biomechanical processes. Previously, we developed a mathematical model with a non-linear growth function but could only confirm the feasibility of this model in clinical trials with a small number of patients. This limited the validity of our model. To increase validity, we applied the model to a larger number of patients.

METHOD

The mathematical model was applied to patient data from a randomised controlled trial as part of the post-evaluation of the model. In this trial, patients with venous leg ulcers were randomised for treatment with either a two-layer bandage or a four-layer bandage.

RESULTS

Data for 186 patients were analysed (two-layer bandage group, n=93; four-layer bandage group, n=93). Using the non-linear growth function, it was confirmed that the two-layer bandage was not inferior to the four-layer bandage. In addition, the mathematical model calculated individual wound healing trajectories and mean wound healing trajectories for both bandage systems. By extrapolating to t→∞, the two-layer bandage had a marginal benefit and resulted in a persistent wound area that was 7% of the initial wound area compared with 17% for the four-layer bandage.

CONCLUSION

This analysis supported the previously performed statistical analysis, and allowed us to obtain details of the treated study population that may help in non-inferiority trials via extrapolation. It also provided new insights into the wound healing process by generating wound healing trajectories.

Fine-Sampled Photographic Quantitation of Dermal Wound Healing Senescence in Aged BALB/cByJ Mice and Therapeutic Intervention with Fibroblast Growth Factor-1

Objective: To determine quantitative parameters of dermal wound healing senescence in aged BALB/cByJ mice (an important animal model of aging) and to evaluate the potential for therapeutic intervention by fibroblast growth factor-1 (FGF-1). Approach: Utilize a novel noninvasive fine-sampled photographic methodology to quantify wound healing parameters for healing phases from wounding through to wound closure. Results: Parameters associated with key healing phases were quantified and compared between nonaged and aged cohorts of both genders. The results identify a sexual dimorphism in dermal wound healing, with nonaged females exhibiting a greater overall healing efficiency than males. This enhanced healing in females, however, senesces with age such that healing parameters for aged males and females are statistically indistinguishable. Topical application of FGF-1 was identified as an effective therapeutic intervention to treat dermal healing senescence in aged females. Innovation: The FGF intervention is being analyzed using a new recently published model. This approach significantly increases the amount of preclinical animal data obtainable in wound healing studies, minimizes cohort number compared with (lethal) histological studies, and permits a direct statistical comparison between different healing studies. Conclusion: Quantitative parameters of dermal wound healing, obtained from noninvasive fine-sampled photographic data, identify topical FGF-1 as an effective therapeutic to treat the senescence of dermal healing present in aged female BALB/cByJ mice.

Structural Variants of a Liver Fluke Derived Granulin Peptide Potently Stimulate Wound Healing

Granulins are a family of growth factors involved in cell proliferation. The liver-fluke granulin, Ov-GRN-1, isolated from a carcinogenic liver fluke Opisthorchis viverrini, can significantly accelerate wound repair in vivo and in vitro. However, it is difficult to express Ov-GRN-1 in recombinant form at high yield, impeding its utility as a drug lead. Previously we reported that a truncated analogue ( Ov-GRN_{12-35_3s}) promotes healing of cutaneous wounds in mice. NMR analysis of this analogue indicates the presence of multiple conformations, most likely as a result of proline cis/ trans isomerization. To further investigate whether the proline residues are involved in adopting the multiple confirmations, we have synthesized analogues involving mutation of the proline residues. We have shown that the proline residues have a significant influence on the structure, activity, and folding of Ov-GRN_{12-35_3s}. These results provide insight into improving the oxidative folding yield and bioactivity of Ov-GRN_{12-35_3s} and might facilitate the development of a novel wound healing agent.