September 11, 2013
Drugs Used To Treat Hepatitis C May Also Treat MERS
redOrbit Staff & Wire Reports - Your Universe Online
A pair of drugs frequently used to help treat hepatitis C patients could be used to help treat Middle East Respiratory Syndrome (MERS) coronavirus, according to research published online earlier this week by the journal Nature Medicine.
Administering a combination of interferon-alpha 2b and ribavirin to monkeys infected with the virus that causes MERS reduced viral replication, subdued inflammation and helped promote lung repair, the authors explained.
The infection is caused by the coronavirus (MERS-CoV) that is closely related to several coronaviruses that infect bats, they said. According to the most recent data from the World Health Organization (WHO), the virus has killed 54 people of the 114 so far infected. There is no proven effective treatment at this time.
However, the new study, which was led by Darryl Falzarano of the National Institute of Allergy and Infectious Diseases' Rocky Mountain Laboratories, suggests that interferon-alpha 2b and ribavirin could be an effective treatment option.
Dr. Angela L. Rasmussen, a research scientist in the Department of Microbiology at the University of Washington, explains that unlike most conventional antivirals, these hepatitis C medications do not directly target the virus. Instead, they moderate the body’s immune response to the infection and help promote the repair of any lung tissue damaged by the disease.
“Rasmussen and her colleagues watched how the lung cells responded to the new treatment by tracking their gene expression profiles,” the Seattle-based university explained. “They did this by studying RNA extracted from the infected monkeys' lungs to track changes in what is called the transcriptome.”
“When a cell needs to use a gene, it copies the gene's DNA-encoded instructions into RNA. That RNA transcript is then read to direct the assembly of a protein,” they added. “By using a ‘lab on a chip’ technology, called a microarray, it is possible to detect and measure RNA transcripts from all the genes in a population of cells.”
Scientists can track how cells or tissues respond to a stimulus, such as an infection or a drug, by analyzing the transcriptome. In the case of MERS, it allowed them to study the host’s response to MERS-CoV in the context of the entire biological system, rather than focusing on one gene at a time, the researchers explained.
Treatment with a combination of interferon-alpha 2b and ribavirin appeared to increase the transcription of genes that fight viral infections, while reducing the transcription of those that promote inflammation, the authors reported. Specifically, they found that the hepatitis drugs increased the transcription of genes that assist in regulating a protein called sonic hedgehog, which helps moderate immune response to more precisely target the virus.
“This honing in reduces collateral damage from broader, less discriminate attack, and helps stimulate repair and growth of lung tissue,” the university explained. “During infection with many severe respiratory viruses… much of the damage is done, not by the virus, but by the body's uncontrolled immune response to the virus.”
“The findings of this new study suggest that, in the case of MERS-CoV infections, interferon-alpha 3b [sic] and ribavirin may work primarily by reducing damaging inflammation of the lung and promoting healing by altering the host response, rather than directly targeting the virus,” they added. “If that is the case, other drugs that can similarly modulate the body's reaction to viral infections may also prove to be effective against MERS-CoV.”