Thiamine (Vitamin B1) protects against glucose- and insulin-mediated proliferation of human infragenicular arterial smooth muscle cells

Accelerated proliferation of arterial smooth muscle cells (ASMC) plays an important role in the development of atherosclerosis, which preferentially affects the infragenicular vasculature in patients with diabetes mellitus. High insulin and glucose levels, which are present in patients with type II diabetes, have an additive effect in infragenicular ASMC proliferation in vitro. Thiamine is a coenzyme important in intracellular glucose metabolism. The objective of this study is to determine the effect of thiamine on human infragenicular ASMC proliferation induced by high glucose and insulin levels in vitro. Human infragenicular ASMC isolated from diabetic patients undergoing lower extremity amputation were used. Cells were cultured at 37°C in 5% CO2. Cells were identified as ASMC by immunohistochemical analysis. Cells from passages 3-5 were exposed to glucose concentrations of 0.1 and 0.2% with and without insulin concentrations of 100 ng/mL and 1000 ng/mL, in the presence or absence of 200 μM of thiamine. Standard hemocytometry and 3H-thymidine incorporation quantified cell proliferation after incubation for 6 days and 24 hr, respectively. The data suggest that thiamine inhibits human infragenicular ASMC proliferation induced by high glucose and insulin. Vitamin B1 intake may prove important in delaying the atherosclerotic complications of diabetes

Syndrome X and diabetes: what is the mystery?

Syndrome X describes a combination of clinical phenomena that have been statistically linked to hyperinsulinema in the absence of frank diabetes. Since its original description, Syndrome X has come to represent several phenotypes that have hemodynamic and metabolic effects on the individual, as well as major effects on the development of vascular disease. Further, this syndrome is reaching epidemic proportions, As such, a thorough understanding of this condition is becoming increasingly important for the modern vascular surgeon. The mainstay of therapy revolves around early diagnosis and management with diet changes, exercise, and reduction of cardiovascular risk factors. Copyright 2002, Elsevier Science (USA). All rights reserved

An expanded series of distal bypass using the distal vein patch technique to improve prosthetic graft performance in critical limb ischemia

AbstractObjectivesThe endovascular first approach has led to increasing complexity for surgical bypass especially in those patients without autogenous conduit. The use of vein interposed at the distal anastomosis has been reported to improve the results of prosthetic grafts. This series expands our initial experience with the distal vein patch technique (DVP) reporting a larger cohort with enhanced follow-up.DesignA retrospective review of prospectively collected data was performed for distal bypasses from July 1995 to November 2008.Materials/Methods1296 tibial bypasses were performed with 270 using the DVP technique. Patient demographics included; 49% diabetes, 20% chronic renal failure, 33% prior failed bypass. Indications for revascularization were claudication (9.3%), rest pain (27.8%), gangrene (22.2%), and non-healing ulceration (40.7%). Lack of vein for the bypass conduit resulted from previous failed grafts (55%), coronary bypass (18%), poor quality vein (23%), or prior vein stripping (8%). Follow-up ranged from 1 to 48 months with graft surveillance by pulse exam, ABI, and Duplex ultrasound. Primary patency and limb salvage ± SE were determined by Kaplan–Meier life-table analysis using Rutherford criteria.ResultsBypasses originated from the external iliac (29%), CFA (55%), SFA (13%), popliteal (1%), and prior grafts (2%). Recipient arteries were below knee popliteal (6%), anterior tibial (25%), posterior tibial (30%), and peroneal (39%). Perioperative graft failure occurred in 13 cases with a total of 41 graft failures leading to 39 major amputations. Primary graft patency from one to four years was 79.8%, 75.6% 65.9%, and 51.2%. Corresponding limb salvage rates were 80.6%, 78.0%, 75.7%, and 67.5%.ConclusionAlthough not addressed by a randomized trial, we believe this expanded series is a more accurate reflection of expected results confirming that the DVP bypass leads to reasonable long-term results for those challenging patients that require prosthetic distal bypass for lower extremity revascularization