Study links AMD to ageing immune cells

According to the study, immune cells called macrophages are more likely to contribute to inflammation and abnormal blood vessel growth in the back of the eye as they age, contributing to vision loss in AMD.Researchers believe a type of microRNA contained within these macrophages, microRNA-150, becomes more prominent with age and encourages the changes that result in vision loss.As such, the team led by Professor Rajendra Apte believe they could one day be used as a biomarker or therapeutic target for aggressive disease and risk of vision loss.{{quote-A:R-W:450-I:2-Q: By understanding what happens with the immune cells in the eye, it may be possible to develop therapies to help patients who can’t be helped with existing drugs. -WHO:Rajendra Apte, Washington University}}“Drug treatments for macular degeneration aren’t effective for some patients, who either have a minimal response or no response at all, and many patients continue to experience vision loss over the long term, even if they have a good initial response to treatment,” Apte said.“But by understanding what happens with the immune cells in the eye, it may be possible to develop therapies to help patients who can’t be helped with existing drugs.”The findings were based on the presence of significantly higher levels of microRNA-150 in macrophages in the eyes of older mice, and people with AMD.The team suggested that if a method is developed to reduce microRNA levels in macrophages, or alter one or more molecular pathways controlled by it, it could be possible to reduce inflammation and interfere with abnormal blood vessel growth in the eye.“Macular degeneration therapies se to be treating disease symptoms, rather than its cause,” medical student and first author Mr Jonathan Lin said.“We focused on the role of macrophages in regulating inflammation and the growth of abnormal blood vessels to see whether it may be possible one day to help people who don’t get much benefit from existing treatments and design therapies that may prevent progression to advanced forms of the disease.”Aside from potential benefits to AMD sufferers, the researchers also believe similar strategies could be eventually applied to other diseases related to ageing.“It’s possible to envision immune-based therapies that would tweak the level of microRNAs so that these macrophage cells no longer contribute to disease,” Apte said.“Such therapies are a long way off, and we need to do a lot more research, but if we could make these older cells more like the younger ones, we might be able to prevent a great deal of vision loss.”