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HCV vaccine potential?
DURHAM, N.C.—There is no vaccine at present for hepatitis C virus (HCV), but thanks to a discovery by researchers at Second Military Medical University in Shanghai, there’s a new pathway that could lead in that direction.
According to the U.S. Centers for Disease Control and Prevention, an estimated 2.7 million to 3.9 million Americans have chronic hepatitis C, and of the individuals who get infected by HCV, roughly 75 to 85 percent of them will develop chronic infection. On a global scale, some 130 million to 150 million people have chronic hepatitis C infection, says the World Health Organization, with about 700,000 deaths worldwide attributed to hepatitis C-related liver diseases each year. Though current antiviral medicines could cure about 90 percent of infected individuals, access to treatment is limited for many.
The researchers in question, led by lead investigator Dr. Zhongtian Qi of the Department of Microbiology at Second Military Medical University, demonstrated how exosomes secreted by umbilical mesenchymal stem cells (uMSC) can suppress HCV infection. Exosomes, noted Qi, are “miniscule fluid-filled sacs that can transfer information and thereby affect immune responses to specific antigens.” Research has found that exosomes can transfer protective host molecules between cells, and mesenchymal stem cells (MSCs) in particular produce large amounts of exosomes. As for umbilical cords, they represent a rich source of stem cells that expand easily and maintain their physiological properties even under cryostorage.
They found that exosomes from the uMSCs “inhibited HCV infection in vitro, especially viral replication, with low cell toxicity,” according to the paper’s abstract.
“Our analysis revealed that microRNAs (miRNAs) from uMSC-derived exosomes (uMSC-Exo) had their unique expression profiles, and these functional miRNAs—mainly represented by let-7f, miR-145, miR-199a and miR-221 released from uMSC-Exo—largely contributed to the suppression of HCV RNA replication,” the authors reported in their abstract. “These four miRNAs possessed binding sites in HCV RNA as demonstrated by the target prediction algorithm. In addition, uMSC-Exo therapy showed synergistic effect when combined with U.S. Food and Drug Administration-approved interferon-α or telaprevir, enhancing their anti-HCV ability and thus improving the clinical significance of these regenerative substances for future application as optimal adjuvants of anti-HCV therapy.”
Qi also noted that “the uMSC also had a synergistic effect when combined with FDA-approved anti-HCV drugs like interferon or telaprevir. Our study demonstrated for the first time that uMSC exosomes were capable of preventing HCV infection, providing new insights and prospects for the development of optimal antiviral agents in the future.” Qi postulated in a press release that the exosomes’ ability to inhibit HCV infection was mainly “because it targeted the virus as it tried to replicate.”
“As the first study to identify exosomes with antiviral potency, this research suggests the potential for a new therapy for hepatitis C to address some of challenges with current treatment, including non-response in some patients and side effects,” added Dr. Anthony Atala, editor-in-chief of Stem Cells Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine.
The paper detailing the team’s results, titled “Exosomal miRNAs derived from umbilical mesenchymal stem cells inhibit hepatitis C virus infection,” was published online ahead of print in Stem Cells Translational Medicine.