Stimulating angiogenesis by hyperbaric oxygen in an isolated tissue construct.

BACKGROUND: Hyperbaric oxygen (HBO2) treatment has been shown to stimulate angiogenesis in prefabricated myocutaneous flaps. We conducted the current study to determine optimal HBO2 treatment intervals for peak angiogenesis. METHODS: Lewis rats were implanted subcutaneously with silicone molds in the inguinal region. Molds contained inguinal fat, a vascular pedicle and Matrigel plug. Thirty-two animals were randomized into four groups: HBO2 Treatment (2.5 atm of 100% oxygen, 90 minutes, 2x/day)--Group 1 (seven days) or--Group 2 (14 days); and Control Treatment (room air at atmospheric pressure)--Group 1 (seven days) or--Group 2(14 days). Implants were harvested, processed for H&E staining, and imaged digitally; angiogenesis was assessed by grade of vascularization at the Matrigel/fat boundary. Intergroup grading differences were assessed statistically. RESULTS: Vascularization in seven-day HBO2-treated implants was significantly increased compared to seven-day controls (p = 0.008). Vascularization in 14-day HBO2-treated implants was significantly decreased compared to 14-day controls (p = 0.012). There was no significant difference between seven-day HBO-treated implants and 14-day controls (p > 0.05). CONCLUSIONS: Short-term HBO2 exposure appears to increase angiogenesis in isolated tissue constructs. Prolonged HBO2 exposure may lead to vascular pruning. Short-term HBO2 exposure appears to expedite the natural vascularization process, resulting in equivalent vascularization in a shorter time.

Botox therapy for ischemic digits.

BACKGROUND: Treating patients with Raynaud's phenomenon who have chronic pain and ulcerations is extremely challenging. Unrelenting pain can lead to dysfunction and disuse, rendering the patient debilitated and/or chronically depressed. Pharmacologic vasodilators and surgical sympathectomies offer variable benefits. Outcomes of symptomatic patients treated with botulinum toxin type A (Botox) injections for Raynaud's phenomenon are presented. METHODS: A retrospective study focused on patient outcomes was performed on 19 patients diagnosed with Raynaud's phenomenon. Patients suffered from chronic ischemic hand pain. All patients had vascular studies to rule out occlusive disease. Fifty to 100 units of Botox were injected into the palm around each involved neurovascular bundle. Preinjection and postinjection laser Doppler scanning was performed on most patients to measure blood flow. RESULTS: Sixteen of 19 patients (84 percent) reported pain reduction at rest. Thirteen patients reported immediate relief; three reported more gradual pain reduction over 1 to 2 months. Three patients had no or minimal pain relief. Tissue perfusion results demonstrated a marked change in blood flow (-48.15 percent to 425 percent) to the digits. All patients with chronic finger ulcers healed within 60 days. Most patients [n = 12 (63 percent)] remained pain-free (13 to 59 months) with a single-injection schedule. Four patients (21 percent) required repeated injections because of recurrent pain. CONCLUSIONS: Vascular function is abnormal in patients with Raynaud's phenomenon. Although its mechanism is unknown, Botox yielded a distinct improvement in perfusion and reduction in pain in patients failing conservative management. Continued research may lead to more specific and reliable treatment for Raynaud's patients.