Current DateSeptember 28, 2021

AMD: a track against resistance to treatment

Adding a protein to the treatment typically given to patients with choroidal neovascularization shows interesting results.

Age-related macular degeneration (AMD) affects 11 million people in the United States. Among them, some are at a therapeutic impasse: the treatments do not work. Researchers from the Baylor College of Medicine have found a way to combat this resistance to treatment. They publish their results in the medical journal Communications Biology.

Resistance to treatment for many patients

Choroidal neovascularization can appear in exudative AMD, known as wet AMD. It can lead to irreparable loss of sight. Usually, doctors suggest that patients take anti-VEGF treatment, which is given as an injection. About a quarter of patients do not respond to treatment, that is, it does not work for them, and about a third will become resistant to treatment after several administrations, which means that the drug eventually stops working for them.

Adding protein improves response to treatment

Using mice, the researchers found that administering a protein, apoliprotein A-I, in addition to anti-VEGF, fights resistance to the treatment and ensures its effectiveness. These results were based on previous research on resistance to anti-VEGF, indicating that macrophages, cells of the immune system, could be linked to this resistance and that the accumulation of cholesterol in these cells participated in the appearance of choroidal neovascularization. Several medical studies have found that the administration of apoliprotein A-I reduces cholesterol in macrophage and endothelial cells, both of which are involved in choroidal neovascularization. “All of these observations suggest that apoliprotein A-I could help fight anti-VEGF resistance and suppress choroidal neovascularization,” says the researchers.

More and more people affected

The researchers used mice of different ages to test their hypotheses. They find that in older rodents, the combination of the two treatments reduced choroidal neovascularization by 47%. They argue that the build-up of cholesterol in macrophages is strongly linked to resistance to treatment. “Our findings encourage us to test the combination of apoliprotein A-I and anti-VEGF in clinical studies to see if it can help patients.” According to the researchers, AMD is expected to affect more and more people in the future. These new discoveries could transform their care.

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