How Does the Diabetes Drug, Pioglitazone, Reduce Protein Loss in the Urine?

Pioglitazone is an insulin sensitising drug used in the treatment of patients with type 2 diabetes. In addition to its blood sugar lowering effect, pioglitazone also has a number of other beneficial effects, one of which is to reduce the loss of protein in the urine. The mechanism of this protein "sparing effect" of pioglitazone is not fully understood. The proposed study will investigate whether pioglitazone has beneficial effects on the filtration characteristics of filters in the kidney that are responsible for retaining protein in the body. The effect of pioglitazone on the size of the pores in the filters and also the electrostatic charge barriers that surround these pores will be investigated. The clinical study will involve 12 patients with type 2 diabetes with minimal urine protein loss, taking low dose pioglitazone for 3 months. Blood and urine samples will be collected at the beginning, mid point and end of the study and used to measure the concentration of specific proteins of different size and electrostatic charge. This data will be used to identify and characterise changes in the filtration properties of the kidney filters during the study.