TXNDC5 and Hyperglycemia: Sustained hyperglycaemia reduces the β cell function through several ways, such as the increase of oxidative stress, activation of c-Jun N-terminal kinase pathway through activated p38 mitogen-activated protein kinase and protein kinase C, the reduction of the pancreatic and duodenal homeoboxfactor-1 function, and the reduction of ERp46 expression [27-29].