Damage criteria for cerebral cortex cells subjected to hyperthermia

Liljemalm, Rickard; Nyberg, Tobias

doi:10.1080/02656736.2016.1181275

Cited by 4 publications

(7 citation statements)

References 28 publications

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“…DSR stands for the change of an unspecified chemical component when cells are exposed to the heating. The damage threshold for cortex cells was calculated as 5% of DSR , which means that cortex cells are in danger when the DSR is above 5%. Maximum temperatures for different laser powers (Figure , blue diamond) were estimated using the temperature model.…”

Section: Resultsmentioning

confidence: 99%

“…The safety of the method is of prime concern for clinical applications. Thermal damage of tissue or cells is a process relating to both exposure temperature and exposure time . The DSR is a non‐linear function of time and heat (see Figure for pulse temperatures) that describes the accumulated damage, as indicated in Figure .…”

Section: Discussionmentioning

confidence: 99%

“…We evaluated the safety of our laser experiments by calculating the DSR using Eqs. 3 and 4, in which parameters were taken from Liljemalm et al

italicDSR = 1 - \frac{C_{1}}{C_{0}},

\int_{0}^{τ} A_{c} \cdot e^{- ((), \frac{E_{a}}{R \cdot T (t)})} italicdt = - \ln \frac{C_{1}}{C_{0}} .

…”

Section: Methodsmentioning

confidence: 99%

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Inhibition of cortical neural networks using infrared laser

Xia

Nyberg

2019

Journal of Biophotonics

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The aim of the present study is to optimize parameters for inhibiting neuronal activity safely and investigating thermal inhibition of rat cortex neural networks in vitro by continuous infrared (IR) laser. Rat cortex neurons were cultured on multi‐electrode arrays until neural networks were formed with spontaneous neural activity. Neurons were then irradiated to inhibit the activity of the networks using different powers of 1550 nm IR laser light. A finite element heating model, calibrated by the open glass pipette method, was used to calculate temperature increases at different laser irradiation intensities. A damage signal ratio (DSR) was evaluated to avoid excessive heating that may damage cells. The DSR predicted that cortex neurons should be safe at temperatures up to 49.6°C for 30 seconds, but experiments suggested that cortex neurons should not be exposed to temperatures over 46°C for 30 seconds. Neural response experiments showed that the inhibition of neural activity is temperature dependent. The normal neural activity could be inhibited safely with an inhibition degree up to 80% and induced epileptiform activity could be suppressed. These results show that continuous IR laser radiations provide a possible way to safely inhibit the neural network activity.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Inhibition of cortical neural networks using infrared laser

Xia

Nyberg

2019

Journal of Biophotonics

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“…Generally, a Gaussian beam profile is used to determine the threshold of monospectral laser in an in vitro setting. [68][69][70] However, in the current study, a square gradient beam profile was chosen as appropriate for a dual laser in order to simplify the experimental procedures. We used a square-core fiber to create a square beam profile because the use of the fiber is easier and more affordable than the phase gating 71 or a micromirror device.…”

Section: Discussionmentioning

confidence: 99%

High-throughput single-cell live imaging of photobiomodulation with multispectral near-infrared lasers in cultured T cells

et al. 2020

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Significance: Photobiomodulation is a well-established therapeutic modality. However, the mechanism of action is poorly understood, due to lack of research in the causal relationship between the near-infrared (NIR) light irradiation and its specific biological effects, hindering broader applications of this technology. Aim: Since biological chromophores typically show several absorption peaks, we determined whether specific effects of photobiomodulation are induced with a combination of two wavelengths at a certain range of irradiance only, rather than a single wavelength of NIR light. Approach: In order to analyze a wide array of combinations of multispectral NIR light at various irradiances efficiently, we developed a new optical platform equipped with two distinct wavelengths of NIR lasers by high-throughput multiple dosing for single-cell live imaging. Two wavelengths of 1064 and 1270 nm were selected based on their photobiomodulatory effects reported in the literature. Results: A specific combination of wavelengths at low irradiances (250 to 400 mW∕cm 2 for 1064 nm and 55 to 65 mW∕cm 2 for 1270 nm) modulates mitochondrial retrograde signaling, including intracellular calcium and reactive oxygen species in T cells. The time-dependent density functional theory computation of binding of nitric oxide (NO) to cytochrome c oxidase indicates that the illumination with NIR light could result in the NO release, which might be involved in these changes. Conclusions: This optical platform is a powerful tool to study causal relationship between a specific parameter of NIR light and its biological effects. Such a platform is useful for a further mechanistic study on not only photobiomodulation but also other modalities in photomedicine.

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“…At higher temperatures employed for thermal ablation, thermally induced cell necrosis occurs, depending on temperature, within ~1 to 2 minutes at 50°C and within seconds at 60°C, both for normal and cancerous cells. 33–35 The cell death mechanism is likely based on irreversible denaturation of structural membrane proteins. 36,37 An advantage of thermal ablation over chemotherapy or radiation therapy is that cells do not develop resistance towards heat.…”

Section: Thermal Therapies In Brain Tumorsmentioning

confidence: 99%

Thermal Therapy Approaches for Treatment of Brain Tumors in Animals and Humans

Bredlau

McCrackin

Motamarry

et al. 2016

Crit Rev Biomed Eng

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Primary brain tumors are often aggressive, with short survival from time of diagnosis even with standard of care therapies such as surgery, chemotherapy, and radiation therapy. Thermal therapies have been extensively investigated as both primary and adjuvant therapy. Although thermal therapies are not yet widely used clinically, there have been several promising approaches demonstrated in both animals and humans. This review presents thermal therapy approaches in animal and human studies, including both hyperthermia (temperatures ~42°C–45°C) and thermal ablation (temperatures > 50°C). Hyperthermia is primarily used as adjuvant to chemotherapy and radiotherapy, and is the most widely studied radiation sensitizer where enhanced efficacy has been shown in human patients with brain cancer. Hyperthermia has additional beneficial effects such as immunogenic effects, and opening of the blood-brain barrier to potentially enhance drug delivery, for example in combination with nanoparticle drug delivery systems. Thermal ablation uses high temperatures for direct local tumor destruction, and it found its way into clinical use as laser interstitial thermal therapy (LITT). This review presents various hyperthermia and ablation approaches, including a review of different devices and methods that have been used for thermal therapies, such as radiofrequency/microwaves, laser, high-intensity focused ultrasound, and magnetic nanoparticles. Current research efforts include the combination of advanced thermal therapy devices, such as focused ultrasound with radiation, as well as the use of thermal therapies to enhance chemotherapy delivery across the blood-brain barrier.

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Damage criteria for cerebral cortex cells subjected to hyperthermia

Cited by 4 publications

References 28 publications

Inhibition of cortical neural networks using infrared laser

Inhibition of cortical neural networks using infrared laser

High-throughput single-cell live imaging of photobiomodulation with multispectral near-infrared lasers in cultured T cells

Thermal Therapy Approaches for Treatment of Brain Tumors in Animals and Humans

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