The peptide hormone hepcidin-25 is found in patients with chronic inflammation. It cuts off the iron supply to the blood and bone marrow and thus causes patients to become anemic, according to Dr. Richard Watt of the BYU Department of Chemistry and Biochemistry.
Watt said this issue of iron deficiency interested him because of its prevalence in common diseases like diabetes, Alzheimer’s disease, and kidney disease.
“There’s a lot of inflammation, and iron metabolism gets disturbed in those diseases,” Watt said. “Several years before I came to BYU in 2006, the hormone hepcidin was discovered. That was a real breakthrough because it explained that iron getting to the bone marrow was being blocked by this hormone, and that’s why patients with inflammation had anemia.”
Watt wanted his lab to develop hepcidin inhibitors so that iron in patients with chronic inflammation could be properly distributed throughout the body. But Watt’s lab first needed a way to measure hepcidin-25 levels in body fluids. An antibody-based test—enzyme-linked immunosorbent assay (ELISA)—can identify a specific protein from a sample, but the test is expensive and time consuming, according to Watt.
Watt turned to Adam Swensen, a student in Dr. John C. Price’s group, at BYU for help finding a fast, affordable method to measure hepcidin. Price’s laboratory group focuses on mass spectrometry and has a small mass spectrometer that can identify hepcidin concentration in samples.
Price’s lab group got permission from the Brigham Young University Internal Review Board to collect body fluid samples from student volunteers.
“To show that this test was useful, we did the human study where we collected blood and urine and measured how much hepcidin was in a variety of different people,” Price said.
The challenge, Price said, was finding a way to separate peptides from the large number of proteins in the blood. Swensen invented a method using a spin filter to isolate the larger proteins and allow the smaller proteins and peptides to pass through, according to Price.
The lab group put the body fluid samples in 96-well plates and used an electrospray and the mass spectrometer to measure the amounts of hepcidin in each sample. If they had used the ELISA, it would cost ten dollars per sample and take twelve hours to complete the process, according to Price, but using their mass spectrometer only cost about two dollars per sample and took two hours.
“The goal was to develop a way that was faster and just as sensitive and accurate as anything out there,” Price said. “But the most important part was the specificity. Biologically different forms of the hepcidin hormone can cause problems with ELISA. With the mass spectrometer assay, we always know when we are looking at the full length of hepcidin.”
Watt said the method Price’s lab group came up with was “fantastic.”
“Price’s lab used a much more common mass spectrometer that is available in most diagnostic laboratories,” Watt said. “We’re hoping that people will start looking at that method and start using it for making it a much more inexpensive way to measure hepcidin.”
“The next step,” Watt said “is to test different inhibitors to find an effective way to block hepcidin in anemic patients.”
Read the full study here.