Aging of macrophages is the cause of blindness
A group of researchers from the Washington University School of Medicine in St. Louis (Washington University School of Medicine, USA) found that macrophages in the retina, as they age, provoke chronic inflammation and the growth of newly formed vessels. As a result, degenerative processes in the central area of the retina, the yellow spot, are accelerated, leading to irreversible loss of vision.
Age–related macular degeneration (AMD) is a chronic progressive disease that slowly or quickly (depending on the form) leads to the death of receptors in the central area of the retina with the formation of a scar and a decrease in vision. AMD does not lead to complete blindness, since the peripheral part of the retina remains intact. But in the center of the field of vision, the patient sees a large black spot.
Currently, it is impossible to completely cure AMD or at least stop the deterioration of vision. There are methods of treatment that slow down the process in some patients, but it still continues, albeit slowly. Understanding the cause of AMD and the processes that support inflammation is certainly important. This would help to develop means of prevention and treatment.
In experiments on mice, it was found that old retinal macrophages carry a large number of fragments of genetic material (microRNAs) that affect protein synthesis. Thus, in old mice, the level of microRNA-150 in macrophages was significantly higher than that in healthy mice.
microRNAs are involved in the regulation of processes inside the cell by influencing gene expression and synthesis of proteins involved in the regulation of lipid transport.
A drawing from an article in JCI Insight
microRNA-150 in macrophages of old mice, as shown by the study, enhances the production of proteins that support inflammation and enhance the growth of newly formed vessels. These vessels have defective walls through which the fluid sweats into the retinal tissue, leading to edema.
The researchers analyzed blood samples taken from healthy people and from patients with AMD. In the latter case, the level of microRNA-150 was increased in macrophages.
The authors call microRNA-150 a potential target for the development of new drugs or a biomarker of the aggressive course of AMD. In addition, they do not exclude that the accumulation of microRNAs in aging macrophages may be the cause of other age-related diseases. It's too early to talk about anything specific, but if in the future it will be possible to "rejuvenate" macrophages, then it will be possible to cure many diseases, including AMD.
Article by J.B. Lin et al. Macrophage microRNA-150 promotes pathological angiogenesis as seen in age-related macular degeneration published in the journal JCI Insight.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of WUSTL: Macular degeneration linked to aging immune cells.