By Sheila Dwyer, MedTech1 StaffNew studies reveal that infections linked to implanted medical devices can be prevented by a method that imitates the body’s own self-defense mechanism against bacteria.
Researchers at the University of North Carolina at Chapel Hill studied hospital-acquired infections in an effort to lower the risk of developing such infections. They found that nitric oxide, a substance produced in the inner lining of the blood cells, could be used to coat implants and ward off bacteria. Nitric oxide is a natural anti-bacterial substance that is vital for the preservation of healthy blood cells.
To ward off bacteria and infection, nitric oxide is stored in a sol-gel based material that is safe enough to enter the body and coat the outside of an implanted device. The nitric oxide is slowly released when it is placed in a watery environment like blood or tissue. The presence of nitric oxide reduces bacteria’s tendency to adhere to the implant and form a film that leads to infection.
“Efforts to reduce infections related to medical implants using conventional antibiotic treatments suffer from the widespread problem of emerging resistance from the most troublesome bacterial strains,” said Dr. Mark H. Schoenfisch, the study’s lead researcher and assistant professor of chemistry. “However, local nitric oxide release mimics our body’s own self-defense mechanisms against foreign cells.”
The body uses a process called phagocytosis to destroy foreign cells. During phagocytosis, immune system cells surround bacteria. These cells release reactive molecules, including nitric oxide, to destroy the foreign elements.
The scientists tested whether nitric oxide in sol-gel fights infection-causing bacteria by exposing it to Pseudomonas earuginosa, a common bacterium. The results showed that bacterial adhesion was often 70 percent lower when nitric oxide was released.
Once bacteria have adhered to an implant and biofilm has formed, the biofilm becomes extremely resistant to the body’s immune system defenses. Researchers said that such biofilms could cause chronic sickness with universal symptoms such as vomiting, headache, nausea, sore throat, abdominal cramps, and fever. Diagnosis is difficult in most cases.
“People in the biomaterial research community have been struggling for years to control bacterial adhesion,” Schoenfisch said. “Despite the many recent advances in medicine, implant-related infection remains a most serious problem. Polymeric nitric oxide release represents a unique strategy, particularly since nitric oxide has a short half-life in blood—just a few seconds—and thus would only have an effect on areas near the implant site where it is needed most.”
More than 50 percent of hospital-acquired infections are due to implanted medical devices, according to the scientists who worked on this study.
Reference:
www.medicaldata.com
Last updated: 18-Sep-01
