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Part of the bloodâocular barrier that prevents certain substances from entering the retina
The bloodâretinal barrier , or the BRB , is part of the
bloodâocular barrier that consists of cells that are joined tightly together to prevent certain substances from entering the tissue of the retina.
[1] It consists of
non-fenestrated capillaries of the
retinal circulation and
tight-junctions between
retinal epithelial cells preventing passage of large molecules from
choriocapillaris into the
retina .
Structure
The blood retinal barrier has two components: the
retinal vascular endothelium and the
retinal pigment epithelium .
[2] Retinal blood vessels that are similar to cerebral blood vessels maintain the inner blood-ocular barrier. This physiological barrier comprises a single layer of
non-fenestrated endothelial cells , which have
tight junctions . These junctions are impervious to
tracer , so many substances can affect the metabolism of the
eyeball . The
retinal pigment epithelium maintains the outer bloodâretinal barrier.
[3]
Clinical significance
Diabetic retinopathy
Diabetic retinopathy , eye damage that frequently occurs as a result of
diabetes , is related to the breakdown of the bloodâretinal barrier.
[4] The barrier becomes more leaky in patients with diabetic retinopathy.
[5]
Other animals
Animal models have shown that the bloodâretinal barrier becomes more permeable to substances in
hypertensive animals (those with high
blood pressure ).
[6]
See also
References
^ Biologyonline.org.
Bloodâretinal barrier [
permanent dead link ] . Retrieved on July 19, 2007.
^ Vinores, SA (1995). "Assessment of bloodâretinal barrier integrity". Histology and Histopathology . 10 (1): 141â54.
PMID
7756735 .
^ Pardianto, G; et al. (2005). "Bloodâretinal-barrier". Mimbar Ilmiah Oftalmologi Indonesia . 2 : 68â69.
^ Azza B. El-Remessy, Mohamed Al-Shabrawey, Yousuf Khalifa, Nai-Tse Tsai, Ruth B. Caldwell and Gregory I. Liou. 2006.
Neuroprotective and Bloodâretinal Barrier-Preserving Effects of Cannabidiol in Experimental Diabetes. American Journal of Pathology , Volume 168, Pages 235-244. Retrieved on July 19, 2007.
^ Lobo, CL; Bernardes, RC; Cunha-Vaz, JG. (2000).
"Alterations of the Bloodâretinal Barrier and Retinal Thickness in Preclinical Retinopathy in Subjects With Type 2 Diabetes" . Archives of Ophthalmology . 118 (10): 1364â1369.
doi :
10.1001/archopht.118.10.1364 .
hdl :
10400.4/836 .
PMID
11030818 .
^ S Lightman, E Rechthand, C Latker, A Palestine and S Rapoport.
Assessment of the permeability of the bloodâretinal barrier in hypertensive rats. Hypertension , Volume 10, Pages 390-395. Retrieved on July 19, 2007.