The prevalence of diabetes is increasing worldwide. The World Health Organisation has estimated that there will be around 300 million diabetics by 2025. The largest increase will occur in Asia. The prevalence of type 2 diabetes is increasing due to a combination of factors: increasing lifespan, sedentary lifestyle, excessive intake of high energy foods, increasing prevalence of overweight/obese people. The Finnish Diabetes Prevention Study Group has clearly shown that changes in the lifestyle of both overweight men and women with impaired glucose tolerance can reduce the incidence of type 2 diabetes by 58%. This finding was confirmed by the Diabetes Prevention Programme which found that lifestyle intervention in individuals with impaired fasting glucose or impaired glucose tolerance reduced the risk of developing type 2 diabetes by 58%, whereas treatment with metformin reduced the risk of type 2 diabetes by only 31%. Both acarbose and troglitazone have also been shown to reduce the progression to diabetes in individuals who are at high risk of developing type 2 diabetes. Since the cure for diabetes remains some way off our concerted efforts should be directed at prevention of diabetes in order to curb the increasing prevalence of diabetes worldwide. Lifestyle changes are more beneficial than long term drug therapy in the prevention of diabetes and should be actively promoted.
Tocotrienols, especially the gamma isomer was discovered to possess cytotoxic effects associated with the induction of apoptosis in numerous cancers. Individual tocotrienol isomers are believed to induce dissimilar apoptotic mechanisms in different cancer types. This study was aimed to compare the cytotoxic potency of alpha-, gamma- and delta-tocotrienols, and to explore their resultant apoptotic mechanisms in human lung adenocarcinoma A549 and glioblastoma U87MG cells which are scarcely researched.
Oxidative stress is thought to be one of the factors that cause neurodegeneration and that this can be inhibited by antioxidants. Since astrocytes support the survival of central nervous system (CNS) neurons, we compared the effect of alpha-tocopherol and gamma-tocotrienol in minimizing the cytotoxic damage induced by H(2)O(2), a pro-oxidant. Primary astrocyte cultures were pretreated with either alpha-tocopherol or gamma-tocotrienol for 1 h before incubation with 100 microM H(2)O(2) for 24 h. Cell viability was then assessed using the MTS assay while apoptosis was determined using a commercial ELISA kit as well as by fluorescent staining of live and apoptotic cells. The uptake of alpha-tocopherol and gamma-tocotrienol by astrocytes were also determined using HPLC. Results showed that gamma-tocotrienol is toxic at concentrations >200 microM but protects against H(2)O(2) induced cell loss and apoptosis in a dose dependent manner up to 100 microM. alpha-Tocopherol was not cytotoxic in the concentration range tested (up to 750 microM), reduced apoptosis to the same degree as that of gamma-tocotrienol but was less effective in maintaining the viable cell number. Since the uptake of alpha-tocopherol and gamma-tocotrienol by astrocytes is similar, this may reflect the roles of these 2 vitamin E subfamilies in inhibiting apoptosis and stimulating proliferation in astrocytes.