OBJECTIVES Numerous mechanisms for the formation of intimal hyperplasia have been proposed but none have been proven or accepted. Our research focuses on the potential role of Hypoxia Inducible Factors (HIFs), VEGF, and PDGF as well as the ERK, PI3-K/AKT pathway in hypoxia mediated intimal hyperplasia processes. We hypothesize that HIF and VEGF will be down regulated with supplemental oxygen in our arteriovenous fistula rabbit model. METHODS Rabbits were randomized into different experimental groups with varying oxygen exposure (21% O2 or 30% O2), and receipt of surgery (surgery with fistula formation, no surgery, or sham operation with skin incision only). Plasma samples were collected at designated intervals in which cytokines and smooth muscle cell proliferation were measured. In addition, cell specimens were exposed to hyperoxic, normoxic, and hypoxic environments with cytokines measured at various time points. RESULTS Placement of an arteriovenous fistula resulted in hypoxia induced HIF stabilization with a concurrent increase in VEGF levels. There was a 4.2-fold induction in HIF-1α levels in animals that were placed in normal air following surgery when compared to animals that were exposed to hyperoxic air. Also VEGF significantly increased post-surgery in the normoxic group, reaching a maximum VGEF level of 959 pg/mL. Plasma VEGF levels in the surgery plus supplemental oxygen group were significantly lower than the normoxic surgery group with almost a 45% reduction in plasma VEGF levels (524pg/mL). Activation of VEGF receptors on smooth muscle cells through ERK1 and AKT pathways resulted in significant smooth muscle cell proliferation and migration. These effects are dramatically reduced in animals that are exposed to a hyperoxic environment of 30% oxygen. CONCLUSIONS Our results suggest that short-term administration of supplemental oxygen inhibits HIFs and VEGF signaling to reduce smooth muscle proliferation in the local blood vessel. These results provide strong support for the therapeutic use of supplemental oxygen following arterial surgery to reduce intimal hyperplasia. These findings also provide a nidus for future clinical trials to determine whether this is clinical applicable in humans.

Objective Intimal hyperplasia (IH) is the cause of most failed arteriovenous fistulas (AVFs), resulting in repeat procedures and leading to increased utilization of scarce health care resources. Our laboratory has previously demonstrated the role of supplemental oxygen in preventing IH and smooth muscle cell proliferation (SMCp) at an artery-to-graft anastomosis and at the deployment site of an intra-arterial stent. This study examines the effect of supplemental oxygen in preventing IH and SMCp in an AVF in a rabbit model. Methods Ninety-six rabbits were randomized into four groups: group 1, control; group 2, no surgery with supplemental oxygen; group 3, AVF without supplemental oxygen; and group 4, AVF with supplemental oxygen. Rabbits receiving supplemental oxygen received 30% oxygen for up to 42 days. Specimens were collected in all groups at days 1, 3, 7, 21, 42, and 90. IH and SMCp were measured at the AVF site as well as in the artery and vein proximal and distal to the AVF. Results IH was first noted at day 7 and significantly increased through day 90 at all locations in the nonoxygen-supplemented groups. No significant IH was noted in the oxygen-supplemented group at any location or any time point. SMCp was noted at day 3 through day 21 in the nonoxygen-supplemented group, whereas almost no SMCp was noted in the oxygen-supplemented group at any location or time point. Conclusions Without oxygen supplementation, SMCp begins at day 3 and is no longer noted at day 21 after creation of an AVF, whereas IH begins by day 7 and increases at least through day 90 after creation of an AVF. Forty-two days of 30% supplemental oxygen inhibits IH and SCMp after creation of an AVF. These data suggest a role for the short-term administration of low-dose O2 to prevent both IH and SMCp after creation of an AVF that may prolong patency and function.

6570 Vidaza and thalidomide were administered to 29 patients with MDS or AML. Vidaza was given at a dose of 75mg/kg subq × 5 days q28 days and Thalidomide starting at 50mg/day and increasing to 100mg. Therapy was well tolerated. Median age was 70 years, and there were 16 males. Two patients had RA, 2 RARS, 9 RAEB, 4 CMMoL, 10 AML and 2 Unknowns. According to IPSS, 1 had low, 7 had Int-1, 5 had Int-2 and 4 had high risk disease, and 2 unclassified (10 had AML). Eleven patients had normal, 14 abnormal and 4 unknown for cytogenetics. Seven patients went off the study due to disease progression (5) or refused therapy (1), died within a week of treatment initiation (1) while 2 are on the first cycle and too early for evaluation. Twenty-five patients are evaluable for outcome. Ten patients received 5 or more cycles of Vidaza. HI was seen in 14/25 (56%), and stable disease in 6/25 (24%) while 5/25 (20%) had disease progression. Six patients experienced complete remission (CR) and are still receiving therapy (24%), 1 experienced HI-E, 2 HI-ANC, 3 HI-P, and 2 had a bilineage improvement (HI-P and ANC and HI-E and ANC). Of 10 AML patients, three went off study due to disease progression, 1 had stable disease, 6 responded with 4 complete remissions (CR), 1 HI-ANC and 1 HI-P. Interestingly, 6/10 AMLs had a history of prior MDS, 3/6 achieved CR, 2/6 had HI (ANC and platelets) and 1 has stable disease (continuing treatment). Among the 4 de novo AMLs, 1 had CR and 3 showed disease progression. We conclude that a combination of low dose Vidaza and thalidomide is well tolerated, and highly effective therapy for the treatment of patients with MDS as well as AML arising from a prior MDS. The ability to treat secondary MDS as out-patient and achieve such a high response rate represents a paradigm shift in AML therapy. No significant financial relationships to disclose.

strated a proapoptotic transcriptome. In vitro, ischemic AKI activated apoptosis (FasL,Dapk1,Bcl10) and TNF family (TNFR1,TNFR2,TNF␣) genes, caspase-3 (100 Ϯ 1.1 vs 106.5 Ϯ 0.8, P ϭ .00325), and PARP (10 Ϯ 3.5 vs 61.8 Ϯ 20.5, P ϭ .047) vs sham. Etanercept inhibited RLMVEC inflammatory genes (E-Selectin, ICAM-1, IL-6, RhoB), caspase-3 activity (100 Ϯ 0.9 vs 102 Ϯ 0.5, P ϭ .096) and PARP activity (10 Ϯ 2.3 vs 10.9 Ϯ 2.2, P ϭ .783) vs vehicle during ischemic AKI.Conclusions: Ischemic AKI drives a proinflammatory and proapoptotic lung EC transcriptome with TNFR1dependent apoptosis. Further study of EC-specific mechanisms of kidney-lung crosstalk during AKI may identify potential therapeutic targets.