Proteoglycans are ubiquitous extracellular
proteins that serve a variety of functions throughout the organism. Unlike other
glycoproteins,
proteoglycans are classified based on the structure of the
glycosaminoglycan carbohydrate chains, not the core
proteins.
Perlecan, a member of the
heparan sulfate proteoglycan (
HSPG) family, has been implicated in many complications of diabetes. Decreased levels of
perlecan have been observed in the kidney and in other organs, both in patients with diabetes and in animal models.
Perlecan has an important role in the maintenance of the glomerular filtration barrier. Decreased
perlecan in the glomerular basement membrane has a central role in the development of diabetic
albuminuria. The involvement of this
proteoglycan in
diabetic complications and the possible mechanisms underlying such a role have been addressed using a variety of models. Due to the importance of nephropathy among diabetic patients most of the studies conducted so far relate to diabetes effects on
perlecan in different types of kidney cells. The various diabetic models used have provided information on some of the mechanisms underlying
perlecan's role in diabetes as well as on possible factors affecting its regulation. However, many other aspects of
perlecan metabolism still await full elucidation. The present review provides a description of the models that have been used to study
HSPG and in particular
perlecan metabolism in diabetes and some of the factors that have been found to be important in the regulation of
perlecan.