The pericyte's role has been extensively studied in retinal tissues of diabetic 
retinopathy; however, little is known regarding its role in such tissues as the 
pancreas and skeletal muscle. This supportive microvascular mural cell, plays an 
important and novel role in cellular and extracellular matrix remodeling in the 
pancreas and skeletal muscle of young rodent models representing the metabolic 
syndrome and type 2 diabetes mellitus (T2DM). Transmission electron microscopy 
can be used to evaluate these tissues from young rodent models of insulin 
resistance and T2DM, including the transgenic Ren2 rat, db/db obese insulin 
resistant - T2DM mouse, and human islet amyloid polypeptide (HIP) rat model of 
T2DM. With this method, the earliest pancreatic remodeling change was widening 
of the islet exocrine interface and pericyte hypercellularity, followed by 
pericyte differentiation into islet and pancreatic stellate cells with early 
fibrosis involving the islet exocrine interface and interlobular interstitium. 
In skeletal muscle there was a unique endothelial capillary connectivity via 
elongated longitudinal pericyte processes in addition to pericyte to pericyte 
and pericyte to myocyte cell-cell connections allowing for paracrine 
communication. Initial pericyte activation due to moderate oxidative stress 
signaling may be followed by hyperplasia, migration, and differentiation into 
adult mesenchymal cells. Continued robust oxidative stress may induce pericyte 
apoptosis and impaired cellular longevity. Circulating antipericyte 
autoantibodies have recently been characterized, and may provide a screening 
method to detect those patients who are developing pericyte loss and are at 
greater risk for the development of complications of T2DM due to pericytopathy 
and rarefaction. Once detected, these patients may be offered more aggressive 
treatment strategies such as early pharmacotherapy in addition to life style 
changes targeted to maintaining pericyte integrity. In conclusion, we have 
provided a review of current knowledge regarding the pericyte and novel 
ultrastructural findings regarding its role in metabolic syndrome and T2DM.