Islet transplantation as a promising treatment for type 1 diabetes has received widespread attention. Oxidative stress plays an essential role in cell injury during islet isolation and transplantation procedures. Antioxidants have been used in various studies to improve islet transplantation procedures. The present study reviews the role of oxidative stress and the benefits of antioxidants in islet transplantation procedures. The bibliographical databases Pubmed and Scopus were searched up to November 2008.All relevant human and animal in-vivo and in-vitro studies, which investigated antioxidants on islets, were included. Almost all the tested antioxidants used in the in-vitro studies enhanced islet viability and insulin secretion. Better control of blood glucose after transplantation was the major outcome of antioxidant therapy in all in-vivo studies. The data also indicated that antioxidants improved islet transplantation procedures. Although there is still insufficient evidence to draw definitive conclusions about the efficacy of individual supplements, the benefits of antioxidants in islet isolation procedures cannot be ignored.

We systematically reviewed the clinical trials which recruited antioxidants in the therapy of pancreatitis and evaluated whether antioxidants improve the outcome of patients with pancreatitis. Electronic bibliographic databases were searched for any studies which investigated the use of antioxidants in the management of acute pancreatitis (AP) or chronic pancreatitis (CP) and in the prevention of post-endoscopic retrograde cholangio-pancreatography (post-ERCP) pancreatitis (PEP) up to February 2009. Twenty-two randomized, placebo-controlled, clinical trials met our criteria and were included in the review. Except for a cocktail of antioxidants which showed improvement in outcomes in three different clinical trials, the results of the administration of other antioxidants in both AP and CP clinical trials were incongruent and heterogeneous.Furthermore, antioxidant therapy including allopurinol and N-acetylcysteine failed to prevent the onset of PEP in almost all trials. In conclusion, the present data do not support a benefit of antioxidant therapy alone or in combination with conventional therapy in the management of AP, CP or PEP. Further double blind, randomized, placebo-controlled clinical trials with large sample size need to be conducted.

Islet transplantation has become a promising treatment in the therapy of type 1 diabetes. Its function improvement, after isolation and before transplantation, is crucial because of their loss both in number and function of islets after isolation procedures. Trace elements sodium orthovanadate (SOV) and sodium molybdate (SM), as well as medicinal plant Teucrium polium L. (TP), showed and possessed high beneficial antioxidative potential and even hypoglycemic properties via their effect on islets. We evaluated the effect of these components in combination on cultured islet function in order to improve pancreatic islet transplantation. Rat pancreatic islets were cultured for 24 h then incubated with different concentrations of TP (0.01 and 0.1 mg/mL) alone and in combination with SOV (1 mM) or SM (1 mM). Insulin concentration in buffer media was measured as islet secretory function. Administration of TP (0.01 mg/mL), SM, and SOV alone or in combination with each other significantly increased insulin secretion at high glucose concentration (16.7 mM); insulin secretion was significantly greater in the group containing both TP and SM than other treated groups (p < 0.05). The combination of the mentioned trace elements especially molybdate with TP could improve islet cells function before transplantation.

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