Diabetic patients undergoing hyperbaric oxygen treatments (HBO2) for refractory lower extremity neuropathic ulcers exhibit more than a 2-fold elevation (p=0.004) in circulating stem cells after treatments and the post-HBO2 CD34+ cell population contains 2 to 3-fold higher levels of hypoxia inducible factors (HIF)-1, -2 and -3, as well as thioredoxin-1 (p≤0.003) than cells present in blood prior to HBO2. Skin margins obtained from two day old abdominal wounds exhibit higher expression of CD133, CD34, HIF-1 and Trx-1 versus margins from refractory lower extremity wounds and expression of these proteins in all wounds is increased due to HBO2 treatment (p≤0.003). HBO2 is known to mobilize bone marrow stem cells by stimulating nitric oxide synthase (NOS). We found that NOS activity is acutely increased in patient's platelets following HBO2 and remains elevated for at least 20 hours. We conclude that HBO2 stimulates vasculogenic stem cell mobilization from bone marrow of diabetics and more cells are recruited to skin wounds.
Management of neuropathic foot ulcers in patients with diabetes (DFUs) has changed little over the past decade, and there is currently no objective method to gauge probability of successful healing. We hypothesized that studies of stem/progenitor cells (SPCs) in the early weeks of standard wound management could predict who will heal within 16 weeks. Blood and debrided wound margins were collected for 8 weeks from 100 patients undergoing weekly evaluations and treatment. SPC number and intracellular content of hypoxia-inducible factors (HIFs) were evaluated by flow cytometry and immunohistochemistry. More SPCs entered the bloodstream in the first 2 weeks of care in patients who healed (n = 37) than in those who did not (n = 63). Logistic regression demonstrated that the number of blood-borne SPCs and the cellular content of HIFs at study entry and the first-week follow-up visit predicted healing. Strong correlations were found among week-to-week assessments of blood-borne SPC HIF factors. We conclude that assays of SPCs during the first weeks of care in patients with DFUs can provide insight into how well wounds will respond and may aid with decisions on the use of adjunctive measures.
It is unclear why many with diabetes develop foot ulcers (DFU) and why some do not heal. It could be associated with genetic variation. We have previously shown that NOS1AP variation is associated with lower extremity amputation in those with diabetes and that circulating stem progenitor cell concentration (SPC) is associated with impaired foot ulcer healing in those with diabetes. The goal of this study was to determine if NOS1AP variation is associated with impaired wound healing and with SPC mobilization in those with DFU. In longitudinal cohort study we demonstrate that NOS1AP variants rs16849113 and rs19649113 are associated with impaired wound healing and with SPC mobilization in those with DFU. We believe that further study of NOS1AP is merited and that it NOS1AP might be associated with a functional impairment.
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