Page 137 - Effects of radiotherapy and hyperbaric oxygen therapy on oral microcirculation Renee Helmers

in Chapter 4 may not have sufficiently undergone a time period to merit late irradiation injury in general and it might have been too early to observe evolution to the actual late phase in the microcirculation or to clinically develop bone exposure akin to ORN. The observed side effects after 5 weeks (reduced vessel density and decreased platelet count) might involve vascular alterations reflecting the onset of IR injury in a transition phase to late IR injury. Therefore, in future experimental studies the observation period should be prolonged and microvascular injury dose-response prevalence should be assessed by correlation of microcirculation alterations, microvascular morphology and histopathology with progression of IR side effects.
Late IR induced oral microvascular changes
The CC video microscope system, based on IDF illumination imaging, has
shown to be feasible in examining and detecting late IR induced changes in
the oral microcirculation. HNCPs that received RT at least 6 months prior to measurement show observable changes in their oral microcirculation that
could be identified and quantified with a chairside assessment approach.
The parameters that express the functionality of the microcirculation such
as capillary density, morphology, vessel diameter and flow were captured by
a simple outpatient clinic procedure that was well tolerated by the patients.
A substantial advantage for in-vivo monitoring of the microcirculation is that
the presence of flow presents the individual vessels in their functional status,
which might reflect the vessel diameter and morphology more accurately
than in a histologic specimen. The study presented in Chapter 4 confirms the
decreased vascularity corresponding with general findings known to occur in
irradiated tissue in the majority of previous studies.3,6,9 Compared to healthy 7 oral tissue, angiomorphology changes were predominantly observed in buccal
mucosa whereas decreased functional capillary density (FCD) was present in mandibular gingival mucosa.
The observation of telangiectasias was a recurrent phenomenon in IR oral microcirculation in the studies presented in Chapters 4, 5 and 6, which were underreported in the literature by others2,9,10,15 and were attributed to compromised vasoregulation that affects hemodynamic function and results in blood stasis.2,9,10
General discussion
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