Determination and identification of placental growth factor in wound fluid from venous leg ulcers

Abstract

Leg ulcers are a common occurrence, particularly within the elderly population. Many hypotheses have been proposed to try to clarify the aetiology of ulceration, but the exact mechanism is still unknown. It is believed, however, that venous hypertension plays a significant role in ulceration. Injury, such as that associated with ulceration, is usually followed by a complex biological response in order to restore homeostasis. Angiogenesis is one such process, whereby new microvasculature is formed from pre-existing vasculature. The vascular endothelial growth factor (VEGF) family is thought to be a main contributor in angiogenesis, although its mechanism is thought to be hindered in ulceration despite up-regulated levels. An important member of the VEGF family is placental growth factor (PlGF), which has been shown to enhance the activity of VEGF as well as being an important growth factor involved in pathological skin angio- genesis. This study focuses on the expression levels of PlGF within wound fluid obtained from bandages used in the compression therapy treatment of venous leg ulcers. Through immunoblotting, fluid from three of the four patients showed the presence of a band 20 kDa in size, suggesting the presence of the PlGF-2 isoform. Furthermore, some patients expressed bands 40 and 70 kDa in size, which may correspond to the non-reduced dimer and the glycosylated form of the protein. Additionally, the level of immunoglobulin G was shown to be elevated in some of the patients. These data would suggest that PlGF can be identified through immunoblotting techniques. Moreover, the level of expression between patients is considerably varied.