Page 126 - Effects of radiotherapy and hyperbaric oxygen therapy on oral microcirculation Renee Helmers

Chapter 6
of capillary loops) remained present after HBOT. Based on these findings, the hypothesis that HBOT redirects the examined microcirculation parameters towards levels corresponding to healthy tissue could only be partially supported.
Late IR changes in oral microcirculation of HNCP show an increased vessel diameter in irradiated buccal mucosa compared to that of healthy, age- matched control.12 In the present study a significant decrease of irradiated buccal mucosal Øbv was observed 6 months after HBOT, which indicates a trend consistent with previous measurements of Øbv in healthy buccal tissue.12 Additionally, the marginally increased percentage of buccal mucosal angioarchitecture to a class 1 was observed 6 months after HBOT which represents a gain of capillary loops akin to normal subepithelial anatomy. Unfortunately, the overall observed expression of class 1 angioarchitecture was not found to be significant after 6 months, nor was the difference in Fd. In our previous study, a described lower mean mandibular gingiva FCD in irradiated tissue compared to healthy tissue might drive the hypothesis of an increase in FCD after HBOT because of its alleged angiogenic potential.12 The data of the present study did not show a rise of FCD in the mandibular gingiva of HNCP in a follow up period of 6 months after start of HBOT. IR dose history showed that the mandibular mucosa received a higher mean dose compared to the mean dose received on the buccal mucosa. In the view of this finding, the microcirculation in the mandibular mucosa may have been injured to a greater extent and therefore be more difficult to resuscitate with HBOT. Furthermore, there is a great variability in individual response to HBOT of the mandibular tissue shown by the large standard deviations in FCD. This could also explain the varying individual efficacy of HBOT on the underlying etiopathology associated with ORN of the jaw. Although previous microcirculation measurements could not detect a significant difference in mean buccal FCD between irradiated and healthy tissue 12, the present study does show a significant increase in mean buccal FCD measured 6 months after HBOT.
Angiopathies such as telangiectasias has frequently been described in tissue that was subject to IR.3,12,13,22,23,35 Altered capillary loops, presenting as telangiectasia-like (ballooning) vessels, were observed at all time points after HBOT. Therefore, it cannot be concluded that HBOT is able to restore capillary loop vascular morphology and reverse pathology associated with microvascular endothelium. However, the degree of “ballooning” of vessels was effectively decreased after HBOT as represented by the measured decreased Øbv. This
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