Glutathione And Cataracts

Cataracts: Glutathione as a Protective Bio-Mechanism

A healthy eye contains glutathione in very high concentrations, whereas low levels adversely affect the eye. Glutathione maintains the water balance in the lens. It is synthesized in the lens (and elsewhere) and is essential to normal metabolism. Glutathione can benefit lens function by:

    • Preserving the physicochemical integrity of proteins in the lens
    • Maintaining action of the sodium-potassium transport pump and molecular integrity of lens fibers (protein)
    • Maintaining molecular integrity of lens fiber membranes and acting as a free radical scavenger to protect membranes and enzymes from oxidation
    • Preventing free-radical-induced photochemical generation of harmful by-products
    • Reactivating oxidized vitamin C, which improves antioxidant capability in the lens

Although the oxygen level within the eye lens is very low, the lens still derives a substantial proportion of ATP from mitochrondrial (aerobic) oxidative phosphorylation, which creates free radicals as an unwanted by-product. Glutathione provides the most important protection against damage from free radical and other oxidants. Glutathione is a very small specialized protein (a tripeptide) consisting of three amino acids: glutamic acid, cysteine, and glycine. Glutathione is concentrated within the eye lens and is readily oxidized by damaging oxidants. Those oxidants are chemically reduced (neutralized) as glutathione is chemically oxidized in cytoplasm of cells within the lens. When glutathione levels decline in the epithelial cells (or the entire lens), cell damage and cataract formation can occur unabated.

Lens epithelial cells and superficial lens fiber cells synthesize glutathione. Additional glutathione is transported into the lens from the aqueous humor.59Oxidized glutathione can be regenerated (i.e., reduced) by the enzyme glutathione reductase that uses the coenzyme called reduced nicotinamide adenine dinucleotide phosphate (NADPH), which is the cofactor derived from the dietary or supplemental B vitamin: niacin or niacinamide, also known as vitamin B3. Regeneration of reduced glutathione from oxidized glutathione is especially important because it is the chemically reduced form of glutathione that is effective in neutralizing (chemically reducing) free radicals. Glutathione is unique in its ability to regenerate its chemically reduced state by simply finding an electron donor. This cycle allows one molecule of glutathione to continually act as a free radical scavenger.

Reduced glutathione diffuses into the lens fiber cells, moving toward the lens center, while oxidized glutathione moves toward the lens surface. Impediment of diffusion in an older lens is a possible cause of nuclear cataract. The rate of diffusion between superficial and deeper layers of the lens decreases with age. Consequently, proteins and lipids in nuclei of older lens are more affected by oxidative stress.

If I have cataracts or other eye ailments, why do I care about Glutathione?

The reducing compound glutathione (GSH) exists in an unusually high concentration in the eye lens where it functions as an essential antioxidant vital for maintenance of the tissue’s transparency – and a protection against cataracts. In conjunction with an active glutathione redox cycle located in the lens epithelium and superficial cortex, GSH detoxifies potentially damaging oxidants such as H2O2 and dehydroascorbic acid.

Recent studies have indicated an important hydroxyl radical-scavenging function for GSH in lens epithelial cells, independent of the cells’ ability to detoxify H2O2. Depletion of GSH or inhibition of the redox cycle allows low levels of oxidant to damage lens epithelial targets such as Na/K-ATPase, certain cytoskeletal proteins and proteins associated with normal membrane permeability. The level of GSH in the nucleus of the lens is relatively low, particularly in the aging lens, and exactly how the compound travels from the epithelium to the central region of the organ is not known.

Recently, a cortical/nuclear barrier to GSH migration in older human lenses was demonstrated by Sweeney et al. The relatively low ratio of GSH to protein -SH in the nucleus of the lens, combined with low activity of the glutathione redox cycle in this region, makes the nucleus especially vulnerable to oxidative stress, as has been demonstrated with use of in vivo experimental animal models such as hyperbaric oxygen, UVA light and the glutathione peroxidase knockout mouse. Effects observed in these models, which are currently being utilized to investigate the mechanism of formation of human senile nuclear cataract, include an increase in lens nuclear disulfide, damage to nuclear membranes and an increase in nuclear light scattering. A need exists for development of therapeutic agents to slow age-related loss of antioxidant activity in the nucleus of the human lens to delay the onset of cataracts.

In another recent study conducted in Germany, glutathione levels were measured in normal human lenses (obtained from an eye bank) and from cataract lenses obtained from routine cataract surgery. In normal lenses, glutathione levels decreased gradually with advancing age. Cataract lenses contained only about one-tenth as much glutathione as normal lenses. As glutathione levels fell, oxidation of lens proteins increased. There is evidence that oxidation of lens proteins is a significant factor in the development of cataracts. Glutathione is one of the major antioxidants (which provide protection against oxidation) found in our lens tissue. The development of cataracts is often preceded by a decline in lens glutathione levels. Strategies designed to prevent glutathione depletion may therefore help prevent cataracts.

Glaucoma, Macular Degeneration, Cataracts and Glutathione

Glutathione plays a significant role in the protection of the eyes from oxidative stress, which leads to unclear eyesight and eventually blindness. There have been previous studies exemplifying the fact that when faced with a lack of glutathione in the eyes, there is a greater chance of Open-Angle Glaucoma, Macular Degeneration and Cataracts. As we get older, we are unable to see things as clearly and then we need reading glasses. This is called presbyopia. Your eyes create glutathione to protect against the oxidation that the sunlight produces according to Dr. Daria Davidson, a board certified medical doctor focusing on holistic medicine with 30 years of practice.

“Oxidative stress occurs when there is an imbalance between the production of the reactive oxygen species and the eyes’ biological systems being able to readily detoxify the reactive intermediate and easily repair the resulting damage,” from Wikipedia. If you have free radicals from oxidative stress, you need an antioxidant to reduce the free radical—an oxidation reduction reaction. Glutathione donates and extra electron to accomplish this. This reducing environment is preserved by enzymes and components like glutathione that maintain the constant status of metabolic energy which is ATP (Adenosine triphosphate) in the cell.

Without ATP the cell becomes sluggish. In some respects ATP is like oil or lubrication is to an engine. Disturbances of the oxidative state cause toxic effects to the DNA.

Oxidative stress contributes to many different health issues, Alzheimer’s, Parkinson’s disease, atherosclerosis, heart failure, heart attack, and so on according to Wikipedia.

According to Dr. Daria Davidson, glutathione is the guardian of the cell, it neutralizes free radicals better than anything, and is the best thing you can have to support the function and structure of your body in every cell. Along with keeping glutathione levels high it’s beneficial to keep superoxide dismutases and coenzyme q10 levels high too.

According to the statistics in this country age macular degeneration is second only to diabetes in causing blindness. Worldwide the number one cause of blindness is cataracts. In Australia, the number one cause is open-angle glaucoma. But what’s important is that all three of these conditions are related with low levels of glutathione in the eye.

Journal of Ocular Pharmacology and Therapeutics in April of 2000 “the reducing compound exists in an unusually high concentration in the lens where it functions as a accentual antioxidant and vital for maintenance of the tissues transparency.”

Dr. Davidson goes on to say that “Cataracts are caused by the lens becoming cloudy. This article is related to the lens which is specifically related to cataracts. Glaucoma is not a lens issue. Macular degeneration is not a lens issue. They are issues of the eye but not related to the lens.”

The article goes on to say, “In conjunction with glutathione the oxidation reduction cycle located in the lens epithelium detoxifies this potentially dangerous oxidant. The depletion of glutathione or the inhibition of the cycle to occur causes oxidative damage resulting in a clouding of the lens,” which is what cataracts are.

Journal of Ocular Service in 2007 “Deficiency in glutathione has been linked to ocular disease and viral infection, endogenous glutathione (glutathione your body makes. exodogenous is glutathione they give to you) plays a role in safeguarding active transfer processes across the surface of the mucosa of the eye and also within the tear film. Glutathione is the most abundant endogenous antioxidant molecule in tear fluid.”

Dr. Davidson goes on to say, “So you have tear ducts in your eyes that lubricate the surface of your eye. The tear ducts then are actually letting some glutathione come outside of the cell that is in the fluid to bath the area. Glutathione outside of the cell can put out some free radical damage but not near as well as when it in inside the cell. It is called the guardian of the cell although there will be some glutathione outside the cell, the glutathione you make yourself have a increased effect for you. There are glutathione eye drops available to you, but most of them are used in Japan to help keep the eyes healthy. Of course if you make more glutathione for yourself, you’re going to be much healthier.”

Mutation research in 2006 – The Role of Oxidative Stress in Glaucoma “Increasing evidence indicates that reactive oxygen species (free radicals” play a key role in pathogenesis (disease) of primary Open-Angle Glaucoma the main cause of irreversible blindness worldwide.”

This article suggests that Glaucoma is the main cause of blindness world wide whereas other sources claim that cataracts are. In either case, glutathione is a major player.

Progress in Retinal and Eye Research in 2003 “The high concentration of glutathione in the lens in believed to protect structural proteins and enzymes for proper biological functioning. The lens of both biosynthetic and regenerating systems for glutathione to maintain its large pool size. However aging lens are lens under oxidative stress show an extensively diminished size of glutathione pool.

In summary, glutathione and the health of your eye, glutathione is needed for every cell of your body to function optimally. We know that certain cells under particular stress, liver cells have a very high amount of glutathione because they are the wash machine of the body. Lungs are also high in glutathione to handle the toxins that we breathe. Skin is high in glutathione to deal with the free radical damage caused by sunlight and the eyes are likewise high in glutathione because they too are exposed to sunlight. If you keep your eyes healthy, the likely hood of getting a diagnosis goes down.