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.

Bacterial clearance reverses a skewed T-cell repertoire induced by Salmonella infection.

Salmonella typhimurium invades the spleen, liver, and peripheral lymph nodes and has recently been detected in the bone marrow and thymus, resulting in a reduced thymic size and a decline in the total number of thymic cells. A specific deletion of the double-positive cell subset has been characterized, yet the export of mature T cells to the periphery remains normal. We analyzed Salmonella pathogenesis regarding thymic structure and the T-cell maturation process. We demonstrate that, despite alterations in the thymic structure, T-cell development is maintained during Salmonella infection, allowing the selection of single-positive T-cell clones expressing particular T-cell receptor beta chains (TCR-Vß). Moreover, the treatment of infected mice with an antibiotic restored the normal thymic architecture and thymocyte subset distribution. Additionally, the frequency of TCR-Vß usage after treatment was comparable to that in non-infected mice. However, bacteria were still recovered from the thymus after 1 month of treatment. Our data reveal that a skewed T-cell developmental process is present in the Salmonella-infected thymus that alters the TCR-Vß usage frequency. Likewise, the post-treatment persistence of Salmonella reveals a novel function of the thymus as a potential reservoir for this infectious agent.