According to a study conducted at North Carolina University in collaboration with Massey University in New Zealand, genetically engineered maggots can be used to elicit human platelet derived growth factor PDGF-BB, which is a potential topical treatment for wound debridement and healing. The results of the study were published on March 22, 2016, in BMC Biotechnology.
Use Of Maggots To Treat Non Healing Ulcers
Max Scott, Professor of Entomology at North Carolina State University, along with his team of researchers and Massey University, New Zealand, used two different methods to produce PDGF-BB from transgenic green bottle fly larvae, scientifically known as Lucilia sericata. First, a heating technique was used to shock the lab-reared green bottle fly larvae at a temperature of 37 degree Celsius. This, however, failed to elicit PDGF-BB in maggot secretions thus rendering it inappropriate for clinical use.
“It is helpful to know that a heat-inducible system can work for certain proteins in the green bottle fly, but the fact that maggots did not secrete the human growth factor makes this technique a non-starter for clinical applications like MDT,” Scott said.
The researchers conducted another clinical trial that involved genetic modification of larvae in a way that they synthesized PDGF-BB when put on a diet lacking tetracycline (antibiotic). This triggered the maggots to release high concentrations of PDGF-BB in their secretions, thus proving that the latter method would be more promising for clinical utility.
“A vast majority of people with diabetes live in low- or middle-income countries, with less access to expensive treatment options,” Scott said. “We see this as a proof-of-principle study for the future development of engineered L. sericata strains that express a variety of growth factors and anti-microbial peptides with the long-term aim of developing a cost-effective means for wound treatment that could save people from amputation and other harmful effects of diabetes.”
Diabetes — A Leading Cause Of Non Healing Ulcers
Diabetes mellitus is one of the most imminent dangers facing the western world today. One in 11 adults suffers from diabetes at present, a figure that will step-up to one in 10 adults by the year 2040. The situation is even more alarming in North America and Caribbean where every one in eight adults has diabetes. The microvascular and macrovascular damages induced by persistently raised blood glucose levels not only result in a huge impact on the quality of lives of U.S. population but also take a toll on the financial resources of American health system. One of the most dreaded complications of long standing diabetes is foot ulcers and non-healing wounds. However, the FDA approval of maggot debridement therapy for wound healing may help reduce burden on U.S. economy, of treating diabetic ulcers that currently amount to $9-13 billion.
The FDA approved medical use of maggots for treating not only diabetic ulcers but also for neuropathic foot ulcers, venous stasis ulcers, pressure and post-surgical wounds. The green bottle larvae use “extracorporeal digestion” to feed on necrotic tissue which can result in wound debridement within a span of one day. Experimental studies have shown that larvae can arrest pathogenic bacterial growth within wounds, especially that of Methicillin-resistant Staphylococcus aureus. PDGF-BB is human platelet derived growth factor, a protein that acts on receptors to induce cell growth and proliferation. This acts through paracrine or autocrine mechanism to activate growth of smooth muscle cells and fibroblasts that play key role in wound healing and repair.
The research showed that genetic modification of maggots through tetracycline-repressible system can enhance wound healing by synthesis of human platelet derived growth factor, a cost-effective means of improving quality of life for patients.