Water-filtered infrared A reduces chlamydial infectivity in vitro without causing ex vivo eye damage in pig and mouse models

Abstract

Originally published at: Rahn, Carolin. Water-filtered infrared A reduces chlamydial infectivity in vitro without causing ex vivo eye damage in pig and mouse models. 2016, University of Zurich, Vetsuisse Faculty. We demonstrated a significant wIRA-dependent reduction of chlamydial infectivity in HCjE cells.Moreover, we observed that wIRA treatment of HCjE prior to infection was sufficient to inhibit chlamydial infectivity and that visible light enhances the effect of wIRA. Irradiation did not reduce cell

wIRA: hyperthermia as a treatment option for intracellular bacteria, with special focus on Chlamydiae and Mycobacteria

“…Moreover, wIRA treatment of HCjE prior to chlamydial infection was sufficient to inhibit chlamydial infectivity, indicating the induction of potential protective effects in wIRA-treated cells possibly via increasing their cell metabolism, since wIRA neither reduced HCjE cell viability nor induced retinal damage post-treatment, thus excluding potential harmful effects. In addition, temperatures during wIRA exposure did not markedly exceed physiological eye temperatures at relevant doses (200 mW/ cm 2 ), suggesting that hyperthermia-related lesions are unlikely [76].…”

“…Apart from these specific reports, it is unknown how chlamydiae react to hyperthermia. Thermal effects of wIRA on chlamydial infections in vitro and in vivo, in the guinea pig conjunctivitis model, have been investigated in recent studies and are summarized in sections below [74][75][76][77][78].…”

“…In vitro studies investigating the effects of irradiation on chlamydial development usually distinguish between application of wIRA alone (780-1400 nm) or wIRA in combination with VIS ranging from 380 to 1400 nm [74,75,76] or 595-1400 [76]. For chlamydiae, wIRA/VIS combinations have shown additional beneficial effects compared to wIRA alone: VIS markedly contributes to temperature increases in the sample at high irradiation doses and extracellular chlamydial stages (EBs) are particularly sensitive to the VIS component, whereas mature chlamydial inclusions are not [75].…”

“…These preliminary results encouraged us to further evaluate wIRA as a possible non-chemical treatment method for blinding trachoma by studying wIRA effects in an ocular in vitro infection model (ocular strain C. trachomatis serovar B and human conjunctival epithelial cells (HCjE)) and noninfected ocular structures in two ex vivo eye models [76]. In vitro, wIRA was applied for 30 min in the temperature-controlled setting (37 C) as described previously [74,75].…”

Thermal field formation during wIRA-hyperthermia: temperature measurements in skin and subcutis of piglets as a basis for thermotherapy of superficial tumors and local skin infections caused by thermosensitive microbial pathogens

“…In contrast to the sole thermally based treatment [28][29][30][31][32][33][34][35], Kuratli et al [36] have described nonthermal reduction of chlamydial infectivity by wIRA in combination with visible radiation. This thermotherapeutic concept, that is, eradication of thermosensitive bacteria by hyperthermia, has been described in detail recently [37][38][39][40][41][42][43].…”