Reactive Astrocytes

The reactive astrocytes have an elevated number of organelles (secondary lysosomes and lipofuscin) and an elevated cellular activity. The reactive astrocytes and therefore also the lipofuscin contained within, if exposed to visible light (400-700 nm) at a high concentration of oxygen (70 mm Hg)—conditions ideal for the formation of free radicals—can cause damage to the cellular proteins and the membrane lipids. The reactive oxygen species can cause damage to cellular and nuclear elements. The presence of high concentrations of toxic substances

(glutamate) in the extracellular space (coming from the reactive astrocytes), causes a massive increase of hydrogen and potassium with an increased permeability of the cell membranes, worsened by free radicals, which makes the cell swell. This cellular edema causes the breakage of the intermediate filaments of the astrocytes and therefore the loss of GFAP immunoreactivity and finally cell death. This fact explains why a reduction of the number of astrocytes in the CGL is observed and a disappearance of the protrusions of the NFL astrocytes has been observed in the elderly.

In the elderly, it has also been observed that the basal membrane of the inner limiting membrane is thicker than in the younger group. The increase in thickness impedes the interchange of substances between the retina and the vitreous humor that represents a reserve of glucose, amino acids, potassium and glutathione, and so on for the retina and a deposit for degradation products.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

Get My Free Ebook

Post a comment