Modification of HIF-1α, NF-aκB, IGFBP-3, VEGF and adiponectin in diabetic foot ulcers treated with hyperbaric oxygen.

Introduction: Diabetic foot ulcers are a frequent complication of diabetes and the first cause of non-traumatic lower limb amputation. They affect quality of life, restrict social productivity and generate a high economic burden for health care systems. Hyperbaric oxygen (HBO2) therapy is an adjunctive treatment option because it improves wound healing in the short term. However, its ability to modulate the pro- and anti-inflammatory balance and the hypoxic cell response in the clinical setting has not been fully described. Objective: To determine modifications in HIF-1α, NF-κB, IGFBP-3, and VEGF expression in wounds as well as circulating inflammatory cytokines in patients with diabetic foot ulcers subjected to HBO2. Materials and methods: We studied 17 ambulatory patients and one hospitalized patient with diabetic foot ulcers classified as Grade 3 or 4 according to the Wagner scale. All underwent HBO2 therapy. Tissue expression of HIF-1α, NF-κB, IGFBP-3, and VEGF was determined by immunohistochemistry. Plasma levels of adiponectin, IL-6, IFN-γ, IL-10 and IL-4 were measured by ELISA and chemiluminescence. Fibrosis and angiogenesis were determined by Masson's trichrome staining. Results: Ulcers in all patients healed after one month of HBO2, and none presented relapses at the one-year follow-up. At the beginning of treatment, HIF-1α and NF-κB expression was observed mainly in the nucleus, whereas these proteins were localized in the cytoplasm at the end of HBO2. There were significant modifications in VEGF expression after therapy, an increase in the plasma level of proinflammatory IL-6, and a decrease in that of IFN-γ. IGFBP-3 expression and plasma levels of adiponectin were increased at the end of HBO2. Increases in fibrosis and angiogenesis were also observed. Conclusion: These results suggest that adjuvant HBO2 modifies the proinflammatory balance related to the cellular response to hypoxia.

Effect of Bovine Lactoferrin Treatment Followed by Acute Stress on the IgA-Response in Small Intestine of BALB/c Mice.

Secretory IgA (SIgA) has a pivotal role in gut homeostasis, which can be disturbed by stress. SIgA is formed by IgA-dimers (associated by the J-chain) and the secretory component, a protein derivative of polymeric immunoglobulin receptor (pIgR). Given the gut immuno-modulatory properties of bovine lactoferrin (bLf), the aim of this study was to compare, after bLf treatment followed by acute stress, the IgA response and IgA-associated parameters in proximal versus distal small intestine. Male BALB/c mice (n = 6) were orally treated with bLf (50, 500, and 5000 µg) for 7 days, then stressed by immobilization for 1 h, and sacrificed. In proximal and distal segments, levels were determined of IgA in gut secretions (enzyme-linked immunosorbent assay [ELISA]), the α-/J-chain and pIgR proteins in epithelial cells (Western-blot), and mRNA expression of the α-/J-chain, pIgR, and interleukins (ILs) in mucosa (RT-PCR). Data were compared by two-way analysis of variance (ANOVA) (significance at P < 0.05). Under acute stress, bLf triggered higher levels of IgA, SIgA, and anti-bLf-IgA as well as greater mRNA expression of pIgR, IL-4, and IL-6 (500 µg) in proximal intestine, while inducing higher levels of the total IgA, α-/J-chain, and pIgR proteins as well as greater mRNA expression of the α-chain and IL-4 (5000 µg) in distal intestine. Compared to unstressed/bLf-untreated mice, plasma corticosterone (a stress biomarker, measured by ELISA) increased in stressed/bLf-treated (0, 50 and 500 µg) and unstressed/bLf-treated (5000 µg) mice. The interplay of corticosterone with gut neuroendocrine factors may have elicited signals creating anti-inflammatory conditions for an IgA-response profile in each intestinal region, according to the bLf concentration administered.