Medica 08: find at Medica recent studies on Depression and Hepatitis C

Medica 2008: Depression: Gene Variants Could Help Identify People at Risk. Grapefruit compound may help combat hepatitis C: A team of researchers from the Massachusetts General Hospital Center for Engineering in Medicine (MGH-CEM) report that HCV is bound to very low-density lipoprotein (vLDL, a so-called “bad” cholesterol) when it is secreted from liver cells and that the viral secretion required to pass infection to other cells may be blocked by the common flavonoid naringenin.

Depression

Certain variations in a gene that helps regulate response to stress tend to protect adults who were abused in childhood from developing depression, according to new research.
Adults who had been abused but didn’t have the variations in the gene had twice the symptoms of moderate to severe depression, compared to those with the protective variations. “Knowing what those variations are eventually could help clinicians individualize care for their patients by predicting who may be at risk or suggesting more precise avenues for treatment”, said NIMH Director Thomas R. Insel, M.D. Almost 15 million U.S. adults have major depression. The new report adds to evidence that a combination of gene variations and life experiences promote the disorder or protect people from it. Variations in many genes are thought to be involved, but few of them have been identified.
The study also supports previous evidence that a stress hormone, corticotropin-releasing hormone (CRH), plays a role in depression. CRH and its receptor are part of a larger hormone system that regulates the response to stress, in part by helping to regulate neurotransmission – the chemical messages through which brain cells communicate with each other. Extreme stress in childhood caused by factors such as abuse can hyperactivate the system, increasing risk of depression in adulthood.
To conduct their research, scientists interviewed 422 adults, mostly African American, and tested their DNA. About one-third of them had the variations in the CRHR1 gene that appear to be somewhat protective if early-life stress has occurred. The finding was strengthened when the researchers repeated the study in 199 white adults and came up with similar results. In addition to racial differences, the two groups differed socioeconomically. The combined findings suggest that the gene variations are protective across the ethnic groups and socioeconomic levels.

Hepatitis C
A compound that naturally occurs in grapefruit and other citrus fruits may be able to block the secretion of hepatitis C virus (HCV) from infected cells, a process required to maintain chronic infection. If the results of this study extend to human patients, a combination of naringenin and antiviral medication might allow patient to clear the virus from their livers. “By finding that HCV is secreted from infected cells by latching onto vLDL, we have identified a key pathway in the viral lifecycle,” says Yaakov Nahmias, PhD, of the MGH-CEM, the paper’s lead author. “These results suggest that lipid-lowering drugs, as well as supplements, such as naringenin, may be combined with traditional antiviral therapies to reduce or even eliminate HCV from infected patients.”

HCV is the leading cause of chronic viral liver disease in the United States and infects about 3 percent of the world population. Current antiviral medications are effective in only half of infected patients, 70 percent of whom develop chronic infection that can lead to cirrhosis or liver cancer.

Grapefruit’s bitter taste is caused the presence of the flavonoid naringin, which is metabolized into naringenin, an antioxidant previously reported to help lower cholesterol levels. Considerable research has suggested that HCV infects liver cells by, in essence, “hitching a ride” onto the natural lipoprotein-cholesterol metabolic pathway. Since earlier evidence has shown that naringenin can reduce secretion of vLDL from liver cells, the researchers examined whether the compound might also lower HCV secretion from infected cells. Their experiments confirmed that naringenin does reduce the secretion of HCV from infected cell lines and showed that the compound inhibits the mechanism for secreting a specific lipoprotein that binds HCV.