Source of Support: None, Conflict of Interest: None
DAG-PKC is a major pathway by which hyperglycemia induces vascular complications in diabetes mellitus. Although the correlation between the activation of DAG-PKC and diabetes vascular and neurological complications is substantial in rodent models of diabetes, there is not much human data because it is difficult to obtain fresh vasculature or neurological tissues for the measurement of DAG-PKC levels. A PKC (isoform inhibitor is only useful in diabetic patients if the same profile of PKC isoforms are activated or expressed in there patients and in the diabetic rodent models. In addition, the secondary markers of PKC activation need to be identified since they can be used to monitor the effectiveness of PKC inhibitor when treated with intensive glycemic control or PKC inhibitor. Progress has been made to identify some of these potential secondary parameters of vascular pathologies such as levels of VEGF, changes in the retinal haemodynamics and endothelial cell functions. These results are only suggestive. Definitive studies are on going and should determine clearly the role of DAG-PKC in the development of the various complications of diabetes mellitus. The clinical trials are now in progress using PKC isoform specific inhibitor in determining the role of activation of DAG-PKC in the vascular complications in diabetic patients. The PKCs may prove ultimately to be suitable targets for therapeutic interventions when their basic regulation in diabetic complications is better understood.