The stability of peptide growth factors exposed to fluids from healing surgical wounds and from nonhealing chronic wounds was examined in vitro. (125)I-Labeled transforming growth factor-beta1 or platelet-derived growth factor-BB was incubated with fluids from healing surgical wounds and fluids from venous stasis or pressure ulcers. Fluids from healing surgical wounds had no appreciable effect on the level of (125)I corresponding to intact growth factor. In contrast, incubation with fluids from several venous stasis or pressure ulcers resulted in significant degradation of these growth factors. Degradation was blocked by broad-spectrum serine proteinase inhibitors and by specific inhibitors of neutrophil elastase. Levels of elastase activity in wound fluids correlated with the ability to degrade peptide growth factors. Further comparisons showed qualitative and quantitative differences in the endogenous proteinase inhibitors, alpha2-macroglobulin and alpha1-antiproteinase. These results could explain, in part, the variable growth factor levels which have been found in chronic wounds. More importantly, the ability of some chronic nonhealing wounds to rapidly degrade exogenously added growth factors has important implications with regard to past and future clinical attempts to use peptide growth factors to treat these types of problem wounds.

Vitamin C (VitC) or ascorbic acid (AscA), a cofactor for collagen synthesis and a primary antioxidant, is rapidly consumed post-wounding. Parenteral VitC administration suppresses pro-inflammatory responses while promoting anti-inflammatory and pro-resolution effects in human/murine sepsis. We hypothesised that VitC could promote wound healing by altering the inflammatory, proliferative and remodelling phases of wound healing. Mice unable to synthesise VitC (Gulo(-/-) ) were used in this study. VitC was provided in the water (sufficient), withheld from another group (deficient) and supplemented by daily intra-peritoneal infusion (200 mg/kg, deficient + AscA) in a third group. Full thickness excisional wounds (6 mm) were created and tissue collected on days 7 and 14 for histology, quantitative polymerase chain reaction (qPCR) and Western blotting. Human neonatal dermal fibroblasts (HnDFs) were used to assess effects of In conclusion, VitC favorably on proliferation. Histological analysis showed improved wound matrix deposition and organisation in sufficient and deficient +AscA mice. Wounds from VitC sufficient and deficient + AscA mice had reduced expression of pro-inflammatory mediators and higher expression of wound healing mediators. Supplementation of HnDF with AscA induced the expression of self-renewal genes and promoted fibroblast proliferation. VitC favourably impacts the spatiotemporal expression of transcripts associated with early resolution of inflammation and tissue remodelling.

There is growing interest in the relationship of hyaluronan and inflammation in a number of physiologic processes including wound healing. The objective of this study was to make a quantitative comparison of inflammation and hyaluronan expression in human normal healing open wounds and in pressure ulcers. Using an open dermal wound model, myeloperoxidase activity was found to peak at day 3. Hyaluronan levels showed a bimodal distribution with transient peaks occurring on days 1 and 7. Mean levels of myeloperoxidase activity in pressure ulcers were significantly higher than at any time in the acute wounds, whereas hyaluronan levels were significantly lower than at any time in the acute wounds. Levels of hyaluronidase activity increased slightly in the postwound period. Hyaluronidase activity in pressure ulcers was significantly elevated compared with the acute wounds. These results suggest a role for increased enzymatic degradation of hyaluronan as a function of inflammation during wound repair. This is the first reported quantitative examination of hyaluronan expression in human acute dermal wounds and in chronic pressure ulcers.

Ducale, Ashley E., Susan I. Ward, Tracey Dechert, and Dorne R. Yager. Regulation of hyaluronan synthase-2 expression in human intestinal mesenchymal cells: mechanisms of interleukin-1␤-mediated induction.

Background and Objectives:  Hyaluronan (HA), a ubiquitous glycosaminoglycan is synthesized by one of three distinct hyaluronan synthases (HAS). The purposes of this study were to determine whether a cause‐and‐effect relationship exists between the proinflammatory cytokine, interleukin‐1β(IL‐1β), and hyaluronan expression in normal jejunum‐derived mesenchymal cells (JDMCs), to identify possible mechanisms involved and to determine the effects of glucocorticoids, a common therapy for intestinal inflammatory pathologies including Crohn’s disease and ulcerative colitis (UC), on cytokine‐mediated hyaluronan expression. Experimental Procedures:  JDMCs were stimulated with IL‐1β for 20 hr with or without pretreatment for 1 hr with mitogen activated protein kinase (MAPK) inhibitors or dexamethasone. HA levels from culture media were quantified using a slot blotting approach. HAS transcript levels were quantified using RPA. Immunoblotting was used to detect and quantify activation of MAP kinases. Results:  Preliminary data of sample tissue from patients with Crohn’s or UC indicated increased HAS transcript levels. Similarly, IL‐1β induced an approximate 18‐fold increase in both HAS2 steady state transcripts and HA levels. These increases were blocked by dexamethasone (95%). Knockdown with siRNA demonstrated that IL‐1β induction of HA expression occurred via HAS2. Immunoblot analysis indicated that IL‐1β activated the ERK1/2, p38 and JNK pathways. Inhibitors of the p38 and ERK1/2, but not JNK, blocked the IL‐1β induction of HA expression (80 and 90%, repectively). Similarly, dexamethasone was also found to block activation of the ERK1/2 and p38 pathways indicating a mechanism for glucocorticoid steroid regulation of HAS expression. Conclusion:  This study provides evidence for proinflammatory cytokine regulation of HA expression in JDMCs. Furthermore, this study provides support for the hypothesis that HA may be one of the targets involved in the treatment of steroid‐dependent inflammatory bowel disease. Support:  This work was supported by NIH GM 58530.