Hemangiopericytoma This is a rare vascular neoplasm, or abnormal growth, that may either be benign or malignant. In its malignant form, metastasis to the lungs, liver, brain, and extremities can be seen. It most commonly manifests itself in the femur and proximal tibia as a bone sarcoma. Hemangiopericytoma is caused by the layering of sheets of pericytes around improperly formed blood vessels. Diagnosis of this tumor is difficult because of the inability to distinguish pericytes from other types of cells using light microscopy. Treatment may involve surgical removal and radiation therapy, depending on the level of bone penetration and stage in the tumor's development.[1]
Diabetic Retinopathy The retina of diabetic individuals often exhibits loss of perictyes, and this loss is a characteristic factor of the early stages of diabetic retinopathy. Studies have found that pericytes are essential in diabetic individuals to protect the endothelial cells of retinal capillaries. With the loss of perictyes, microaneuryisms form in the capillaries. In response, the retina either increases its vascular permeability, leading to swelling of the eye through a macular edema, or by forming new vessels that permeate into the vitreous membrane of the eye. The end result is reduction or loss of vision. While it is unclear why pericytes are lost in diabetic patients, one hypothesis is that toxic sorbitol and advanced glycation end products accumulate in the pericytes. [2]
- ^ Gellman, Harris. "Medscape: Medscape Access". Retrieved 2 November 2011.
- ^ "Pericytes and the Pathogenesis of Diabetic Retinopathy". Retrieved 2 November 2011.