Date post: | 21-Jan-2016 |
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The stimulation of a variety of cell types may lead to the release of microparticles (MPs)
These submicron vesicles bud off from the plasma membrane of the parent cell
They can disseminate a variety of bioactive effects which reflect the cell of origin
They are pro inflammatory and play an important role in mediating inflammation, haemostasis, thrombosis, angiogenesis and vascular reactivity
Elevated levels of MPs occur in inflammatory and autoimmune diseases, atherosclerosis, malignancy and infection
Their levels may reflect disease activity and they can act as useful biomarkers
There is no uniform definition of MPs Identification in previous studies has been
based on their characteristic composition and size
This can help differentiate them from other subcellular structures including apoptotic bodies and exosomes
MPs are described as small membrane bound vesicles ranging in size from 0.1–1μm
They are released from the precursor cells by exocytic budding of the plasma membrane
This process produces a phospholipid rich surface from the plasma membrane lipid bilayer
The membrane (including surface proteins and receptors), cytoplasmic, antigenic and nuclear constituents of the MP released reflect the origin cell
Their composition is also influenced by the type of stimulus leading to their production
We aimed to investigate if MPs were present in the tears of patients with ocular surface inflammation
Identification was based on their previously described characteristic features › Vesicular shape› 0.1-1μm in size› Outer phospholipid membrane
Scanning electron microscopy (SEM) and nile red stain (a lipophilic stain) were used to identify these
Tear samples were collected from 5 inflamed eyes and 4 non-inflamed eyes
The diagnosis in the eyes with ocular surface inflammation was› 3 corneal ulcers, 2 conjunctivitis
Particles characteristic of MPs were identified in all the samples from eyes with ocular surface inflammation
These particles were not present in samples from the control eyes
Multiple particles with the characteristic appearance of microparticles (arrow) in tear sample
Low power SEM. Box indicates area shown in high power in next slide
Multiple particles with the characteristic appearance of microparticles (arrow) in tear sample
High power SEM
Characteristic particles staining with nile red Colour fluorescent picture
We have demonstrated the presence of particles characteristic of MPs in the tears of 5 eyes with ocular surface inflammation
These were not present in the 4 control eyes
MPs are increasingly recognised to play an important role in mediating various disease processes
Further investigation is merited to further define the role of MPs in mediating ocular surface disease