Term Paper
Proteomics of Human Aqueous Humor
Prof.dr.Sabina Semiz
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Table of Contents
Abstract
1. INTRODUCTION
3
2. AQUEOUS HUMOR
3
2.1
Aqueous vs.Vitreous Humor
5
2.2 Formation and Flow of Human Aqueous Humor
6
3. PROTEOMICS OF HUMAN AQUEOUS HUMOR
7
3.1 Classification of Proteins found in Human Aqueous Humor
10
3.2 Proteins Previously Identified in Human Aqueous Humor
11
3.2.1
Vitamin
D-binding protein (GC) and Pigment epithelium derived factor
(SERPINF1) 13
3.2.2 Transforming
growth factor beta 2 (TGFB2) 14
3.2.3 Components
of the complement pathway
14
3.2.4 Osteopontin and Vasorin
15
3.3
Proteins
identified in human aqueous humor for the first time
15
3.3.1
Sorbitol
dehydrogenase (SORD)
16
3.3.2 Filensin,
Phakinin and Platelet derived growth factors
16
3.4
Enzymes
identified in human aqueous humor
16
4. DISCUSSION
18
5. CONCLUSION
20
6. References
21
Abstract
The eye is a double organ which is responsible for receiving information from the
outside world and transforming it into electrical impulses, so they could get to the brain. Its
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a small organ, which does not change it's dimensions from birth until death, and it is there to
convert light into electrical impulses. (Lamb, 2011)
The human eye is a double organ which is working on a principle similar to cameras. The
transparent front of the eye is breaking the beams of light, projecting a smaller and inverted
image on the photosensitive retina where the specialized nerve cells perform conversion into
electrical nerve impulses. (Lamb, 2011)
The eye is the most important human sense because it receives 80% of all information from
the environment, allows conscious perception of light, recognition of colors and depth
perception. (McBride, 2010) In the area of the eye are a number of morphological and
functional systems: optical, accommodative, the system of external eye muscles,
photoreceptive, nervous system, the system for creating and circulating aqueous humor,
cardiovascular, eye protective apparatus and system for maintaining the size and shape of the
eye. The main role in keeping the shape of the eye and provision of nutrients has the aqueous
humor, the central theme of this work. In this study, Krishna R.Murthy et al. (2015) took
aqueous humor samples from different patients, processed further to different fractionation
strategies and did an analysis by mass spectrometry. The results were more than satisfactory
with 386 novel proteins identified in the human aqueous humor.
2. AQUEOUS HUMOR
The eyeball consists of three envelopes. The external, fibrous envelope at the front is
transparent and we call it cornea. In the back of the eye there is the non-transparent sclera.
The cornea has an optical and supporting role, and the sclera does only support. Beneath the
sclera is the middle eye envelope or uvea. Under the eye envelopes are the lens, vitreous and
aqueous humor. (McCaa, 1982)
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The eyeball itself can be divided into two psegments, which are both containing fluids. The
front segment, or front chamber, is localized from the cornea up to the lens, and the back
segment, or back chamber, from the back edges of the lens to the retina. The front chamber is
filled with a fluid that we know as human aqueous humor that feeds the internal tissue of the
eye, while the back chamber carries a gel-like substance that we call the vitreous humor.
These fluids are there to help the eyeball keep its shape. A bigger amount, 4/5 of human
aqueous humor is in the front chamber and 1/5 in the back chamber of the eye. The total
amount of human aqueous humor in one eye is 0.30 ml. The human aqueous humor is
secreted from blood of ciliary fringes by different mechanisms like ultrafiltration, active
secretion and dialysis. (McCaa, 1982) Parts of the eye are shown in Figure 1.
Figure 1. Parts of the Eye (Picture taken from:
https://en.wikipedia.org/wiki/Aqueous_humour#/media/File:Schematic_diagram_of_the_hum
an_eye_en.svg
)
What are actually the most important roles of the human aqueous humor? Aqueous humor has
a function in balancing intraocular pressure, refraction, oxydation and it is important in
nutrition. Besides that, the human aqueous humor takes away wastes, products of
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Aqueous humor is more water-like and located in the front chamber of the eye, between iris
and cornea. It keeps the shape of this part of the eye, and brings nourishment to the eye.
(Healthline, 2015)
2.2 Formation and Flow of Human Aqueous Humor
Making aqueous humor happens in the ciliary body by different and compley
processes. It is made from the blood which is flowing through the cilia extensions. From this
part, the aqueous humor is secreted in the back chamber, from which it flows besides the lens
and enters the front chamber. In the part of the chamber angle (area of the front chamber
which is placed in the part of the cornea joining the planks) we find the so called trabecular
meshwork, aqueous veins (venae aquosae) and Schlems channel. This is the main way
through which the human aqueous humor exits the anterior chamber. (see Figure 2) (Johnson,
2010)
The relation between formation and swelling of the human aqueous humor on the pressure in
the eye which is called intraocular pressure. The disruption of this relation and balance, an
increased or decreased formation, or increased and decreased swelling of the human aqueous
humor, will make an fall or rise in the intraocular pressure, what can mean a risk to the health
of the eye. One of the risks is eye glaucoma, which is the consequence of increased
intraocular pressure. Because of that, the maintenance of intraocular pressure is crucial and
for the prevention and regulation of this and other dangerous diseases. (Brubaker, 1991)
