DIABETES/METABOLISM RESEARCH AND REVIEWS RESEARCH ARTICLE Diabetes Metab Res Rev 2004; 20: 330–336. Published online 22 March 2004 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/dmrr.470 Thiamine and benfotiamine prevent increased apoptosis in endothelial cells and pericytes cultured in high glucose E. Beltramo* E. Berrone S. Buttiglieri M. Porta Department of Internal Medicine, University of Turin, Italy *Correspondence to: E. Beltramo, Department of Internal Medicine, University of Turin, C.so AM Dogliotti, 14, I-10126 Torino, Italy. E-mail: elena.beltramo@unito.it Received: 26 November 2003 Revised: 23 January 2004 Accepted: 27 January 2004 Abstract Background High glucose induces pathological alterations in small and large vessels, possibly through increased formation of AGE, activation of aldose reductase and protein kinase C, and increased flux through the hexosamine pathway. We showed previously that thiamine and benfotiamine correct delayed replication and increase lactate production in endothelial cells subjected to high glucose. We now aim at verifying the effects of thiamine and benfotiamine on cell cycle, apoptosis, and expression of adhesion molecules in endothelial cells and pericytes, under high ambient glucose. Methods Human umbilical vein endothelial cells and bovine retinal pericytes were cultured in normal (5.6 mmol/L) or high (28 mmol/L) glucose, with or without thiamine or benfotiamine, 50 or 100 μmol/L. Apoptosis was determined by two separate ELISA methods, measuring DNA fragmentation and caspase-3 activity, respectively. Cell cycle and integrin subunits α3, α5, and β 1 concentration were measured by flow cytometry. Results Apoptosis was increased in high glucose after 3 days of culture, both in endothelium and pericytes. Thiamine and benfotiamine reversed such effects. Neither cell cycle traversal nor integrin concentrations were modified in these experimental conditions. Conclusions Thiamine and benfotiamine correct increased apoptosis due to high glucose in cultured vascular cells. Further elucidations of the mechanisms through which they work could help set the basis for clinical use of this vitamin in the prevention and/or treatment of diabetic microangiopathy. Copyright  2004 John Wiley & Sons, Ltd. Keywords diabetic retinopathy; endothelium; pericytes; glucose; thiamine; benfotiamine Introduction Onset and severity of vascular complications in both type 1 and 2 diabetes are clearly associated with the duration and degree of hyperglycaemia [1,2]. Supra-physiological concentrations of glucose cause a number of alterations in small and large vessels, the mechanisms of which are not yet fully understood. Among possible mechanisms, increased formation of advanced glycation end products (AGE) [3], increased aldose reductase (AR) activa- tion with consequent hyperglycaemic pseudohypoxia [4], glucose-induced activation of protein kinase C through de novo synthesis of the lipid second Copyright  2004 John Wiley & Sons, Ltd.