Inflammation, the Inflammatory Response, and Macular DegenerationPosted on Sunday, June, 10th, 2012 by in Chronic Disease | Immune Homeostasis (Immune Balance) | Inflammation | Smoking
The retina is the “flat screen” at the back of the eye onto which light is projected when we look at an object. The center of the retina is called the macula. When it is damaged, a condition called macular degeneration, there is a “hole” at the center of one’s vision, making it difficult to recognize faces, read, or drive a car.
As people grow older, they are at greater risk of getting macular degeneration. Risk factors for this condition are: being Caucasian, obese, female, and having a family history of macular degeneration. High blood pressure, high cholesterol, and eating few fruits and vegetables, also add to one’s risk.
However, the greatest known risk of damaging the retina comes from smoking tobacco. Current and former smokers have 6.6 times the chance of developing macular degeneration as compared to those who never smoked. [Unfortunately, if you smoked one or more packs a day, even having quit 15 years previously, still increases the risk that you will have damaged your retina in some way.]
Even after decades of study, we do not understand the underlying mechanisms of macular degeneration. Increasingly however, the literature suggests that inflammation is a major contributor to destruction of the retina.
Immune system inflammation is the body’s first line of defense against pathogens such as viruses, bacteria, fungi, and parasites. Inflammation is also important to control mutating, cancer cells.
However, excessive amounts of tissue-damaging inflammation can damage healthy neighboring tissue. High sensitivity C-reactive protein (hs-CRP) is a blood marker associated with inflammation, and an indication that too great an inflammatory response is being generated by the immune system.
A seven year study of hs-CRP levels of 4900 people was conducted in the Netherlands. Individuals with high levels of C-reactive protein had a significantly greater risk of acquiring macular degeneration compared to those with “normal” baselines of the inflammatory marker. Additionally, other studies suggest that 75% of patients with macular degeneration have “inflammatory” genes that release pro-inflammatory cytokines that are associated with the condition.
Some clinicians have recommmended using-steroidal anti-inflammatory medications to control macular degeneration, yet contradictory studies suggest that frequent aspirin use leads to macular degeneration.
We know that high aspirin consumption leads to excessive bleeding in digestive tracts and the eyes. Perhaps the association of high aspirin use and macular degeneration is due the bleeding aspect of excessive aspirin consumption.
Inflammation is important for our survival, but it must be the appropriate amount of inflammation; it must be a balanced response of just enough inflammation to defend and heal, but not so much that it damages tissues.
Controlling excessive inflammation, without the side-effects of medications such as bleeding, would likely help limit degeneration of the retina.