Demodex Bacteria Inhibits Corneal Wound Recovery

Written by on April 27, 2012 in Demodex Mites, What Causes Rosacea? with 1 Comment

This just published abstract takes the demodex bacteria based irritation line of research a step further.

Researchers in Ireland were able to show that demodex bacteria Bacillus oleronius proteins induced an “aberrant wound healing response” in  the cells irritated by scratch in a cornea.

The aberration appeared as an elevated immune response and an chagnes in cells’ inability to move like normally expected.

A Quick Revision

Previously we have learnt from NRS sponsored research from Dr. K. Kavanagh – “Dr. Kevin Kavanagh and colleagues at the National University of Ireland-Maynooth found that the bacterium Bacillus oleronius stimulated an immune system response, inducing high levels of T-cell proliferation, in 79 percent of patients with subtype 2 rosacea, compared with only 29 percent of patients without the disorder. T-cell proliferation induces an inflammatory response, evident as papules and pustules.”

Further, we also know that “two antigenic proteins of size 62 and 83 kDa” isolated in Bacillus oleronius have the potential to stimulate an inflammatory response in patients with papulopustular rosacea.

Correlation between ocular demodex and ocular symptoms tells us that those with rosacea linked to demodex bacteria, ocular symptoms may also be exacerbated by a reaction to the bacterial proteins.

Latest Research

Demodex-associated Bacillus proteins induce an aberrant wound healing response in a corneal epithelial cell line (hTCEpi).

Invest Ophthalmol Vis Sci., 2012 Apr 24

O’Reilly N, Gallagher C, Katikireddy K, Clynes M, O’Sullivan F, Kavanagh K.

Department of Biology, NUI Maynooth, Maynooth, Co. Kildare, ABC 127, Ireland.

Purpose: The aim of the work presented here was to establish the response of a corneal epithelial cell line (hTCEpi) to protein extracted from a bacterium (Bacillus oleronius) previously isolated from a Demodex mite from a rosacea patient.

Methods: The response of the corneal epithelial cell line to Bacillus proteins was measured in terms of alterations in cell migration and invasiveness. Changes in the expression of metalloproteinase genes and proteins were also assessed.

Results: The results indicated increased cell migration (14.5 fold, p = 0.001) as measured using 8 µm PET inserts (BD Falcon) in a transwell assay and invasiveness (1.7 fold, p = 0.003) as measured using 8 µm Matrigel (BD Biocoat) invasion inserts in a 24 well plate assay format, following exposure to the Bacillus proteins.

Cells exposed to the Bacillus protein showed a dose dependent increased in expression of genes coding for matrix metalloprotease-3 (MMP-3) (61 fold) and matrix metalloprotease-9 (MPP-9) (301 fold).

This dose dependent increase in gene expression was also reflected in elevated levels of MMP-9 protein (1.34 fold, p = 0.033) and increased matrix metalloprotease activity (1.96 fold, p = 0.043) being present in the culture supernatent.

Cells also displayed reduced levels of β-integrin (1.25 fold, p = 0.01), indicative of increased motility, and elevated levels of vinculin (2.7 fold, p = 0.0009), suggesting altered motility.

Conclusion: The results indicate that exposure of corneal epithelial cells to Bacillus proteins results in an aberrant wound healing response as visualized using a scratch wound assay.

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About the Author: David Pascoe started the Rosacea Support Group in October 1998. .

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1 Reader Comment

  1. Brady Barrows says:

    Thanks Dave for the comment on this research paper which I have added to my list:

    http://irosacea.org/html/demodex_rosacea_research_papers.html

    You certainly are coming around to appreciating the role demodex plays in demodectic rosacea. Of course, not all rosacea is demodectic but it should be ruled out in a differential diagnosis of rosacea. The RRDi is the only non profit organization for rosacea that recognizes demodectic rosacea as a rosacea variant.

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