Pan European Networks - Horizon 2020 - page 41

origin and one of non-human primate origin, even at high doses of wIRA/
VIS or long term exposure.
Additionally, in a collaborative project with a group of the Darmstadt
Technical University in Germany, wIRA treatment has been demonstrated
to be undamaging to the pig eye. Incidentally, because wIRA/VIS reduces
infectivity of directly irradiated extracellular chlamydial infectious EBs,
potential applications for decontamination of healthcare and/or
agriculture settings may be viable.
The benefits of wIRA treatment
Potential advantages of using wIRA to treat trachoma patients as an
alternative or combination therapy in the future are manifold. The wIRA
technology is already commercially available and has been shown to
speed wound healing, reduce inflammation, and decrease secondary
wound infections in clinical trials.
The wIRA device is applicable in the field, easy to use and does not
require skilled medical personnel. The efficacy of a single dose of wIRA
has been shown
in vitro
to reduce the chlamydial infectious burden by
50% without detriment to the host cells. Additionally, the anti-chlamydial
effect of wIRA is most effective late in the chlamydial developmental
cycle when anti-chlamydial drugs are less effective.
Inappropriate or inconsistent antibiotic therapy is a primary factor
leading to the emergence of drug-resistant bacteria, which is particularly
problematic in developing countries where antibiotics can be acquired
only periodically and where use of expired or counterfeit medications is
common. Because the use of wIRA may facilitate reduced dependence
on antibiotic treatment, it has the potential to help reduce the incidence
of bacterial antibiotic resistance. Because wIRA exposure reduces
production of infectious chlamydiae, it may be expected to
reduce/prevent
C. trachomatis
transmission as well as trachoma
disease progression.
Current investigations
When it comes to treating trachoma patients, wIRA shows promise as a
valuable therapeutic strategy. On-going work in our lab aims to
demonstrate proof of concept for ocular wIRA treatment in an
in vitro
conjunctival cell culture model and an
ex vivo
animal model of ocular
infection, respectively.
The transition to a more clinically relevant human conjunctival epithelial
cell culture and ocular
C. trachomatis
strain wIRA exposure model, from
our current successful and established non-conjunctival permanent
epithelial cell and non-ocular
C. trachomatis
strain model, is now one of
the main aims in the Borel research group at CABMM. It is expected that
wIRA will reduce inclusion formation and production of infectious
C.
trachomatis
EBs in conjunctival epithelial cells by 50% or more. Multiple
or longer wIRA doses will likely further reduce inclusion formation and
production of infectious EBs without deleterious effects on the host cells.
Our second aim will be to establish an
ex vivo
animal eye model (sheep)
for infection with the animal chlamydial pathogen
C. pecorum
followed
by exposure to wIRA. Natural infection with
C. pecorum
in sheep causes
conjunctivitis. Preliminary
in vitro
data have already shown the effective
reduction of wIRA/VIS in
C. pecorum
-infected cells. We expect that the
ex vivo
sheep eye infection model will show that wIRA exposure reduces
chlamydial inclusion formation, shedding of infectious
C. pecorum,
and/or
ocular inflammation.
Following abdominal surgery, a lower rate of
wound infections was observed after post-
operative wIRA/VIS irradiation compared to
treatment with VIS alone. However, few
preliminary data on the treatment of infectious
conditions with wIRA irradiation have been
reported so far. The direct effect of wIRA on
pathogens
in vitro,
and in particular on obligate,
intracellular agents such as chlamydiae, has
not been shown before.
Acute chlamydial infection
Recent
in vitro
investigations by our group have
revealed the exposure of chlamydiae prior to
host cell infection. The exposure of Chlamydia-
infected cells to wIRA/VIS irradiation reduces
both the number of chlamydial inclusions that
develop within host cells and the subsequent
production of infectious chlamydiae, without
any negative impacts on host cell viability. The
efficacy of wIRA/VIS irradiation in reducing the
infectious chlamydial forms (the elementary
bodies (EB)) was demonstrated in animal-
infecting as well as human-infecting
chlamydial species.
Fig. 3 shows
C. trachomatis
EBs either
irradiated with wIRA/ VIS (20 minutes,
3700W/m
2
) or not irradiated (control), prior to
infection of HeLa monolayers (human-derived
cervical epithelial cell line). Cultures were
incubated for 43 hours, fixed, and immune-
labelled with anti-chlamydial LPS (green,
chlamydial inclusions) and DAPI (blue, host cell
nuclei). Frequency of inclusions per nucleus
was calculated, and irradiation resulted in an
approximately 50% reduction in the number of
host cells infected (not shown; p ≤0.05, n = 3,
t
test). Representative microscopic pictures at
1,000 times magnification are shown.
Furthermore, multiple-dose irradiation, as
applied in clinical settings of wound healing and
reduction of wound infection, resulted in an
even more profound reduction of chlamydial
burden
in vitro
. Importantly, we showed that
wIRA/VIS does not induce cytotoxicity in two
different permanent cell lines, one of human
H O R I Z O N 2 0 2 0 P R O J E C T S : P O R TA L
I S S U E S I X
41
O P T O M E T R Y
Fig. 3 Irradiation of
chlamydial elementary
bodies reduces their
infectivity on host cells
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