Whole-body Hyperthermia Treatment Research Articles

The Role of Hyperthermia in Potentiation of Anti-Angiogenic Effect of Cisplatin and Resveratrol in Mice Bearing Solid Form of Ehrlich Ascites Tumour

The aim of this study was to investigate the therapeutic potential of resveratrol in combination with cisplatin on the inhibition of tumour angiogenesis, growth, and macrophage polarization in mice bearing the solid form of an Ehrlich ascites tumour (EAT) that were exposed to whole-body hyperthermia treatment. In addition, we investigated whether a multimodal approach with hyperthermia and resveratrol could abolish cisplatin resistance in tumour cells through the modulation of histone deacetylase (HDAC) activity and levels of heat shock proteins (HSP70/HSP90) and contribute to the direct toxicity of cisplatin on tumour cells. The tumour was induced by injecting 1 × 106 EAT cells subcutaneously (sc) into the thighs of Balb/c mice. The mice were treated with resveratrol per os for five consecutive days beginning on day 2 after tumour injection and/or by injecting cisplatin intraperitoneally (ip) at a dose of 2.5 mg/kg on days 10 and 12 and at a dose of 5 mg/kg on day 15. Immediately thereafter, the mice were exposed to systemic hyperthermia for 15 min at a temperature of 41 °C. The obtained results showed that the administration of resveratrol did not significantly contribute to the antitumour effect of cisplatin and hyperthermia, but it partially contributed to the immunomodulatory effect and to the reduction of cisplatin toxicity and to a slight increase in animal survival. This treatment schedule did not affect microvessel density, but it inhibited tumour growth and modulated macrophage polarization to the M1 phenotype. Furthermore, it abolished the resistance of tumour cells to cisplatin by modulating HDAC activity and the concentration of HSP70 and HSP90 chaperones, contributing to the increased lifespan of mice. However, the precise mechanism of the interaction between resveratrol, cisplatin, and hyperthermia needs to be investigated further.

Association of plasma cytokines and antidepressant response following mild-intensity whole-body hyperthermia in major depressive disorder

Whole-body hyperthermia (WBH) shows promise for the treatment of major depressive disorder (MDD). Because MDD is associated with increased inflammation, and anti-inflammatory agents show some promise as antidepressants, the current study sought to identify the acute and longer-term immune effects of WBH in participants with MDD and to explore whether these effects associate with the procedure’s antidepressant properties. Thirty participants who met DSM-IV-TR criteria for MDD were randomized to receive a single session of WBH (n = 16) or sham treatment (n = 14). Hamilton Depression Rating Scale (HDRS) scores were assessed at baseline and 1, 2, 4, and 6 weeks post-treatment (WBH vs. sham), and plasma cytokine concentrations were assessed at baseline, immediately post-treatment, and 1 and 4 weeks post-treatment. As previously reported, WBH produced a rapid and sustained antidepressant effect. When compared to sham, WBH increased plasma interleukin (IL)-6 immediately post-treatment (time by treatment: χ2(3, N=108) = 47.33, p < 0.001), while having no effect on other cytokines acutely and no impact on IL-6, or any other cytokine, at 1 or 4 weeks post treatment. In the study sample as a whole, increased IL-6 post-treatment was associated with reduced HDRS depression scores over the 6 weeks of follow-up (F(1, 102.3) = 6.74, p = 0.01). These results suggest a hitherto unrecognized relationship between hyperthermia, the immune system, and depression, and may point to WBH as a novel modality for exploring behavioral effects of IL-6 when the cytokine is activated in isolation from the inflammatory mediators with which it frequently travels.

Abstract A023: First in-human, safety and preliminary efficacy study of (neo)adjuvant, model-based, whole-body hyperthermia treatment in advanced solid cancer patients or stage IV (TxNxM1) metastatic pancreatic adenocarcinoma patients: Liquid biopsies

Abstract Hyperthermia, the procedure of raising the temperature of a part of the entire body above normal for a defined period of time, is applied alone or as an adjunctive treatment to various established cancer treatment modalities such as radiotherapy and chemotherapy. Whole-Body Hyperthermia (WBHT), in contrast to local or regional hyperthermia, represents the only hyperthermia modality available for patients with disseminated malignancies. The biological rationale for the treatment of malignant disease by heat is driven by a number of reasons; a) the survival of cells depends on the temperature and duration of heating in a predictable and repeatable way; b) the tumor cell environment (such as hypoxia, poor nutrition, and low pH) that negatively influences the tumor cell killing by ionizing radiation and some chemotherapy regimens, is beneficially influenced by heat therapy; c) the differential sensitivity of normal and tumor cells to heat is dependent on cell type and environmental conditions; d) heat treatment enhances the biological effect of both radiation and chemotherapy agents. The biological rationale is based on a direct cell-killing effect at temperatures in the range of 41– 42°C. A systematic review of van der Horst et al, 2018, addressed clinical trials that used local or whole-body hyperthermia treatment (at variable temperatures) in pancreatic cancer patients. In those described trials, the weighted estimate of the treated population median overall survival was 11.7 compared to 5.6 for the control cohorts. In addition, locoregional hyperthermia (42-44°C) clinical trials showed that the weighted estimate median overall survival of the treated population was 15 months compared to 9 months in control cohorts. The MATTERS trial is a first in-human clinical investigation in advanced solid cancer patients or pancreatic adenocarcinoma patients (TxNxM1). The justification of the design is based on evaluation of pre-clinical data and clinical evaluation of clinical data, safety and/or performance of similar devices/therapies. The study is a mono-centric, non-randomized trial in which the safety and preliminary efficacy of whole-body hyperthermia will be evidenced. Well designed and performed early-stage correlative studies have the potential to strongly influence further clinical development of oncology clinical trials, and correlative data obtained from early stage trials has the potential to provide important guidance on the design and ultimate success of later stage trials. Blood samples will be collected for analysis of immunological panels (e.g. cytokines, chemokines), exosome research, RNA expression profiles. Urine will be collected for analysis of exosome research. The samples will be collected during different timepoints (before, during and after treatment). Citation Format: Ivana Gorbaslieva, Dana Mustafa, Robin Colenbier, Marc Peeters, Dirk Ysebaert, Vera Saldien, Luigi Brancato, Oleg Rudenko, Johan Van den Bossche, John Paul Bogers. First in-human, safety and preliminary efficacy study of (neo)adjuvant, model-based, whole-body hyperthermia treatment in advanced solid cancer patients or stage IV (TxNxM1) metastatic pancreatic adenocarcinoma patients: Liquid biopsies [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr A023.

Systematic review of the registered clinical trials for oncological hyperthermia treatment

Background The use of heat to treat various diseases is called hyperthermia treatment (HT). Since the 1970s, the anti-cancer effects of HT have been investigated. Different HT techniques can be categorized as local, regional and whole-body hyperthermia treatment (WBHT). We aim to provide a summary of recent research done on HT to treat cancer. Methods In July 2020 ClinicalTrials.gov were systematically searched for all trials including hyperthermia and cancer registered between 2000 and 2020. Studies were excluded when they did not concern hyperthermal treatment, when they were not oncological studies, when they were observational or other non-interventional studies. Results Of 1654 identified trials, 235 were included. Of these 235 studies, 123 described the use of HIPEC (52.3%), 44 other types of regional HT (18.7%), 45 local HT (19.1%) and 15 WBHT (6.4%). A steady increase (720%) in research to hyperthermic intraperitoneal chemotherapy (HIPEC) can be observed in the last decade. Although HIPEC is the most researched HT modality, an evolution in other HT technologies could be observed during the past decade. Conclusions Research to HT to treat cancer has expanded fast. Some techniques, for example HIPEC start to be used outside of research context, but overall, more research is needed to establish a clear effect of these HT techniques.

A monocentric, first-in-human (FIH), safety and preliminary efficacy study of (neo) adjuvant, model-based, whole-body hyperthermia (WBHT) treatment in advanced solid cancer patients or stage IV metastatic pancreatic adenocarcinoma patients.

TPS625 Background: Whole-Body Hyperthermia (WBHT) represents the only hyperthermia modality available for patients with disseminated malignancies. The rationale for the treatment of malignant disease by heat is based on a direct cell-killing effect at temperatures in the range of 41– 42°C and driven by a number of reasons. Phase-I mining and phase-I veterinary (dog) clinical study proved the safety of WBHT treatment alone and in combination with standard of care therapy in dogs with cancer. A systematic review addressed clinical trials that used WBHT in pancreatic cancer patients. In these trials, the weighted estimate of the treated population median overall survival was 11.7 compared to 5.6 for the control cohorts. Methods: The is a first in-human, mono-centric, non-randomized trial to establish the safety and preliminary efficacy of WBHT treatment with the TempoCure (medical device) alone in patients with advanced solid cancer (cohort A) or in combination to SOC chemotherapy treatment in patients with stage IV metastatic pancreatic adenocarcinoma (cohort B). The study of 12 to 20 patients is not powered for any statistical analysis. The analysis will be limited to descriptive statistics, considered the doses provided and the extra blood sampling taken at different time points. The treatment is applied under deep anaesthesia in a unit connected to the operating room at the hospital. Cohort A1. Three patients with advanced solid cancer will be subjected to repetitive WBHT starting with 2 hours (day 1), 4 hours (day 8) and 6 hours (day 15) using the TempoCure to keep the patient at a temperature of 41.5°C. The patient’s body temperature will be monitored by specific sensors (liver, oesophageal, rectal and cutaneous). Cohort A2. The highest WBHT duration with acceptable side effects from cohort A1 will be applied to three additional patients with advanced solid cancer, once a week and for 15 days in total. Cohort B1. Three pancreatic cancer patients will be subjected to repetitive WBHT starting with 2 hours (day 1), 4 hours (day 8) and 6 hours (day 15) using the TempoCure to keep the patient at a temperature of 41.5°C and in combination with the standard of care chemotherapy. Cohort B2. The highest WBHT duration with acceptable side effects from cohort B1 will be applied in combination with chemotherapy to three pancreatic cancer patients, once a week and for 15 days in total. Major inclusion criteria are: Adequate liver structure (confirmed by CT scan) allowing the placement of the liver sensor; Adequate coagulation defined as; PT (%) ≥ 70%; aPTT ≤ ULN; Von Willebrand Factor Antigen ≥ LLN; Von Willebrand Factor Activity ≥ LLN; PFA COL/EPI CT ≤ 1.15 ULN; PFA COL/ADP CT ≤ 1.15 ULN. Enrollment to Cohort A1 began in July 2021. Clinical trial information: NCT04467593.

Mild Whole-Body Hyperthermia-Induced Interstitial Fluid Pressure Reduction and Enhanced Nanoparticle Delivery to PC3 Tumors: In Vivo Studies and Micro-Computed Tomography Analyses

Abstract In this study, we performed in vivo experiments on mice to evaluate whether whole-body hyperthermia enhances nanoparticle delivery to PC3 (prostatic cancer) tumors. PC3 xenograft tumors in immunodeficient mice were used in this study. The mice in the experimental group were subjected to whole-body hyperthermia by maintaining their body temperatures at 39–40 °C for 1 h. Interstitial fluid pressures (IFPs) in tumors were measured before heating, immediately after, and at 2 and 24 h postheating in both the experimental group and in a control group (without heating). A total of 0.2 ml of a newly developed nanofluid containing gold nanoparticles (AuNPs) was delivered via the tail vein in both groups. The micro-computed tomography (microCT) scanned images of the resected tumors were analyzed to visualize the nanoparticle distribution in the tumors and to quantify the total amount of nanoparticles delivered to the tumors. Statistically significant IFP reductions of 45% right after heating, 47% 2 h after heating, and 52% 24 h after heating were observed in the experimental group. Analyses of microCT scans of the resected tumors illustrated that nanoparticles were more concentrated near the tumor periphery rather than at the tumor center. The 1-h whole-body hyperthermia treatment resulted in more nanoparticles present in the tumor central region than that in the control group. The mass index calculated from the microCT scans suggested overall 42% more nanoparticle delivery in the experimental group than that in the control group. We conclude that 1-h mild whole-body hyperthermia leads to sustained reduction in tumoral IFPs and significantly increases the total amount of targeted gold nanoparticle deposition in PC3 tumors. The present study suggests that mild whole-body hyperthermia is a promising approach for enhancing targeted drug delivery to tumors.

Inhibition of B16 murine melanoma metastasis and enhancement of immunity by fever-range whole body hyperthermia

Purpose: Whole body hyperthermia (WBH) has been regarded as a promising alternative therapy to cure late stage cancer with metastasis. As the final biological and therapeutic effects are dependent on the specific protocol, the potential of using a microwave-based WBH approach for metastasis inhibition is established and its typical results are discussed.Materials and methods: The effectiveness of a 30-min whole body hyperthermia (WH) on animals, raised to a rectal temperature of 40.2° ± 0.3°C for 30 min followed by 84 h observation by 2450 MHz microwave irradiation, were evaluated. In an experimental lung metastasis model by injection of B16-F10 melanoma, lungs were removed from sacrificed mice 16 days after tumour implantation, and the expression of heat shock protein, inter-cellular adhesion molecule 1 (ICAM-1), proliferating cell nuclear antigen (PCNA) and cyclin D1 was examined. CD4+, CD8+ and NK cell subpopulation in peripheral blood were measured by flow cytometry before and after the last treatment.Results: The best therapeutic effect was obtained when the mice were treated with WBH in combination with the initial chemotherapy with cis-diaminodichloroplatinum (CDDP) and dacarbazine (DTIC) (p < 0.05). The WBH alone has an advantage of reduced toxicity and lower cost. Heat shock protein (HSP) expression increased in the hyperthermia groups. Reduction of PCNA and cyclin D1 was observed in the mice treated with WH alone or in combination with chemotherapy. In the hyperthermia groups, CD4+/CD8+ decreased while the NK increased slightly.Conclusions: The whole body hyperthermia protocol described in this work inhibits B16 tumour metastasis by inhibiting cell proliferation, neovascularisation and stimulating favourable immune responses. It demonstrated that WBH treatment benefits therapy of metastasis cancers.

Effect of propofol upon brain after whole-body hyperthermia in rats

To investigate the effect of propofol upon acute cerebral insult during whole-body hyperthermia (WBH) in rats. Sixty male Wistar rats were randomly divided into 6 groups. All the animals were trained with place navigation test of Morris water maze (MWM) for 5 days pre-study. After training, some rats received anesthesia only but not WBH treatment as control, other rats were anesthetized with intraperitoneal injection of 3.0 ml/kg of chloral hydrate and 100 or 150 mg/kg of propofol followed with WBH process (keeping rat core temperature at 42 degrees C for 30 min). Space memory was checked using spatial probe test 24 h after WBH intervention. Rat brain was then removed in 24 h post-WBH to separate hippocampal regions for the detection of neuronal apoptosis with TUNEL method and ultramicrostructural changes by electron microscope. The escape latency were smaller in groups B0, C0, D0, C and D than that in group B (P < 0.05) while smaller in groups B0, C0, D0 than in groups B, C, D respectively. The amount of apoptotic neurons in hippocampus increased orderly as following with no significant differences in group B0, C0 and D0: group B0, C0, D0 < group D < group C < group B (P < 0.05). The injury degree of neuronal ultramicrostructure in hippocampus in group C after WBH were more severe than that in group D but better than that in group B. Propofol alleviates the WBH-induced acute cerebral insult by inhibiting the hippocampal neural apoptosis.

Comprehensive evaluation on the heating capacities of four typical whole body hyperthermia strategies via compartmental model

The whole body hyperthermia (WBH) is being regarded as a very promising way of efficiently treating patients with tumors already distributed throughout the human body. However, quite a few important issues still remain unclear, some of which are how much energy can be deposited into human body or how long will it take for a patient’s body core temperature to rise from its normal to the desired point. Aiming to provide a general background for tackling the complex heat transfer behavior throughout the whole human body during a WBH treatment, we propose in this paper to adopt a compartmental model for a comprehensive evaluation of several existing typical WBH methods. The heating performance of four heating strategies such as contact-heating-based WBH (CWBH), radiative- heating-based WBH (RWBH), extracorporeal circulative-heating-enabled WBH (EWBH) as well as interventional WBH (IWBH) were compared and evaluated. The characteristics of different WBH methods were assessed in detail from the engineering perspective. Further, the effect of the thermal regulation mechanism and brain cooling upon body temperature response during WBH was investigated. Specially, this research explained for the first time the reason why intravascular heating strategies could have a higher heating efficiency in raising body core temperature than that of the heating from outside. This study would help probe into the complex behavior of the temperature response of the human body subject to various WBH. The theoretical model and calculation method could serve as a valuable guidance for future tumor treatment planning.

Current status of radiant whole-body hyperthermia at temperatures >41.5°C and practical guidelines for the treatment of adults. The German ‘Interdisciplinary Working Group on Hyperthermia’

The term ‘extreme’ whole-body hyperthermia (WBH) describes the procedure of raising a patients’ body-core temperature to 41.5–42.0°C for 60 min. WBH represents the only hyperthermia technique that enables systemic heat treatment in patients with disseminated malignancies and is, therefore, usually combined with systemic chemotherapy. Up to now, several WBH-approaches have proved to be safe and associated with acceptable toxicity rates when radiant heat devices are employed. Until the late 1990s, the use of radiant WBH was restricted to a few specialized treatment centres worldwide. During the last 5 years, a larger number of WBH-devices were put into operation particularly in Germany. As a result, a novel generation on phase II trials on chemotherapy and adjunctive WBH in patients with various malignancies has been completed. Based on the promising results observed herein, first multi-centric phase III-trials on chemotherapy ± WBH have been initiated, with a considerable number of patients treated at German institutions. The authors are members of the ‘Interdisciplinary Working Group for Hyperthermia’ (‘Interdisziplinäre Arbeitsgruppe Hyperthermie’), a sub-group of the German Cancer Society. They formulated these guidelines in order to standardize the WBH treatment procedure and supportive measures, to provide some uniformity in the selection of patients to be treated and to define criteria of a successful WBH-treatment. These recommendations may be helpful to ensure the quality of WBH performed at different institutions.

A thermometry system for quality assurance and documentation of whole body hyperthermia procedures

Since December 2001, the Department of Oncology and Medical Physics, Haukeland University Hospital, Norway has been conducting whole body hyperthermia (WBH) studies, treating patients with either ovarian carcinoma or non-Hodgkin lymphomas. Accurate and reliable thermometry instrumentation is important in all types of hyperthermia procedures, particularly in WBH, where the target patient body temperature is 41.8°C. Reliable documentation of side-effects in clinical studies is also dependent on precise temperature monitoring, since in this temperature range even small, but systematic, inaccuracies (0.1–0.2°C) in the temperature monitoring is expected to affect the amount of side effects. Readily available heating and temperature data from previous treatment sessions of the same patient is also valuable for precise temperature control in future treatment sessions. The WBH thermometry system implemented at Haukeland University Hospital is described. It is based on commercially available components, including standard medical thermistor probes, and includes a temperature calibration and verification facility. The thermometry system is accurate, reliable, easy to use, comfortable for the patient and relatively inexpensive. By implementing the Steinhart-Hart polynomial fit to standard medical thermistor probe data, it is shown that the WBH treatment thermometers used can measure the patient body temperatures with a short- and long-term accuracy of ± 0.01°C.

Comparison of the Anti-Tumor Effects of Various Whole-Body Hyperthermia Protocols: Correlation with HSP 70 Expression and Composition of Splenic Lymphocytes

Whole-body hyperthermia (WBH) has been used as an adjunct approach to radio-/chemotherapy for tumor therapy for many years. However, the molecular mechanism underlying the enhancement of tumor control is not clearly understood. It has been hypothesized that WBH might activate immune system by inducing the expression of heat shock proteins (HSPs), which are thought to facilitate the presentation of tumor-specific antigens. In the present work, we examined the effects of various thermal doses of WBH on tumor growth delay and HSP70 levels in tumors on C57BL/6 mice, as well as on splenic lymphocyte subpopulations. The maximal WBH effect (about 40% decrease in tumor weight) was achieved by a 2-hour WBH treatment everyday at 40.0°C. By using this treatment schedule, the populations of CD3+/CD4+ T cells and CD3+/CD8+ T cells increased by 4 and 3 times, respectively, at the end of WBH treatment period. When the length of day-by-day WBH treatment was longer than 2 hours or the frequency of WBH treatment was lower than once a day, the effect of tumor growth delay and the population of CD3+ T lymphocyte in spleen increase were discounted. On the other hand, the HSP70 levels in tumor nodules rose continuously as the WBH treating time increased, but the populations of NK cells in spleen did not change significantly. The results suggest that an increased CD3+ T lymphocyte population is closely related to the anti-tumor effect of WBH, which might be a useful marker for effectiveness of hyperthermia. However, neither the levels of HSP70 nor the NK cell populations in spleen appear to correlate to tumor control.

Effect of whole body hyperthermia (39°C, 1 h) on radiation-induced apoptosis in Swiss mice

Mild whole body hyperthermia (WBH) treatment when given prior to radiation exposure is known to protect mice against radiation-induced hemopoietic death. This radioprotective effect seems to be mediated through WBH-induced cytokines and growth factors. Exposure to total body irradiation (TBI) also induces cell death by apoptosis in animal cells. The present studies were therefore carried out to investigate whether WBH pretreatment could protect mice against radiation-induced apoptotic death. The extent of apoptosis in bone marrow cells derived from mice at different time intervals after WBH, TBI and whole body hyperthermia treatment given 20 h prior to total body irradiation (WBH+TBI) treatments was studied by three independent methods namely DNA ladder assay, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling assay and caspase-3 assay. The studies have revealed that the mild WBH treatment (39°C, 1 h) when given 20 h prior to TBI (8 Gy) results in reduction in TBI-induced apoptosis. The results imply that WBH-induced impairment of apoptosis may have some role in WBH-induced radioprotection in Swiss mice.

Effect of nitric oxide on mortality of mice after whole body hyperthermia

The objective of this study is to find the role of nitric oxide (NO) in the haemodynamics of mice subjected to heat stress caused by Whole Body Hyperthermia (WBH) treatment. L-arginine (L-arg), a natural substrate for NO synthase (NOS), N-nitro-L-arginine methyl ester (L-NAME), a preferential inhibitor of endothelial NOS, and dexamethasone, a preferential inhibitor of inducible NOS, have been used to study the role of NO in thermal injury caused by WBH treatment. Nitrite in plasma and mortality of Swiss male mice subjected to WBH treatment induced by radiant heat (40°C fo 1 h at 50-55% relative humidity), were monitored in mice pre-treated with either L-NAME, dexamethasone or L-arg. A batch of mice subjected to 24 h fasting prior to WBH treatment was also used to study the above parameters. Injections with 1.5 mg/kg or above of L-NAME just before WBH treatment, induced mortality in mice, with a corresponding drop in plasma nitrite values. L-arg (8 mg/kg) pre-treatment reversed the killing caused by L-NAME in WBH treated mice. L-arg (60 mg/kg) pre-treatment induced mortality in mice subjected to WBH treatment. In the fasted group, a very low dose of L-arg (8 mg/kg) given before WBH treatment led to a significant increase in plasma nitrite levels. In both the normal and fasted groups of mice, 120 mg/kg of L-arg pre-treatment resulted in a sharp increase in plasma nitrite values and subsequent death of mice. The results throw up an important finding, in that the interaction of elevated body temperature, with either a decrease or over production of nitrite oxide, leads to modulation of thermal injury of mice, caused by WBH treatment.

Whole-body hyperthermia in the treatment of breast cancer

Hyperthermia has two major effects on cancer. (1) Tumor cells can be killed, because they are more sensitive to heat than normal cells. Thereby, membrane components can also be released. Both events can induce antitumoral immunity. (2) It can revert chemoresistance of tumors. The patients in this study were postsurgery and treated with radiotherapy and/or chemotherapy. Additionally to chemotherapy, nonspecific immune stimulation was applied. All patients were studied more than 5 years after the primary diagnosis. A total of 105 patients received the above-mentioned therapy. The 35 patients of the 'hyperthermia group' received whole-body hyperthermia treatment. The distribution of tumor at various staging was practically identical in both groups, as was the median follow-up period: 70 months. In the control group (105 patients) 12 patients died and 61 developed metastasis within a mean period of 36 months. On the contrary, in the hyperthermia group (35 patients) no patient died and only three developed metastasis within 52 months.

Effect of mild whole body hyperthermia on cytotoxic action of N-methyl- N′-nitro- N-nitrosoguanidine in Swiss mice

Studies were carried out to ascertain the efficacy of mild whole body hyperthermia (WBH) as a modifier of N-methyl- N′-nitro- N-nitrosoguanidine (MNNG) cytotoxicity in mice. Adult Swiss male mice, 6–8 weeks old, weighing about 25 g were exposed to mild WBH (39°C, 1 h) in a precision temperature controlled environmental chamber maintained at 50–60% relative humidity. Twenty-four hours after treatment, animals were administered with different doses of MNNG either by intraperitoneal (i.p.) injections or by feeding through drinking water and were monitored for survival. The studies revealed that the exposure of animals to mild WBH, 24 h prior to MNNG administration results in an increase in survival and recovery in mean body weight compared with those administered with MNNG only. This suggests that prior WBH treatment can effectively reduce the MNNG cytotoxicity in mice.

Regulation of immune activity by mild (fever-range) whole body hyperthermia: effects on epidermal Langerhans cells.

Inflammation of the skin and systemic fever, both of which occur with injury or infection, include a hyperthermic component that many believe constitutes a physiological stress. Such increases in local or systemic body temperature may also have a regulatory effect on immune function. Langerhans cells (LCs), the dendritic cells of the skin, continuously monitor the extracellular matrix of the skin by taking up particles and microbes that they then carry to draining lymph nodes for presentation to T lymphocytes. We hypothesize that the thermal element of inflammation and/or fever may help regulate the activation and migration of LCs out of the epidermis. To test this hypothesis, Balb/ c mice were exposed to a mild (39.8 degrees C +/- 0.2 degrees C), long-duration (6 hours) whole body hyperthermia (WBH) treatment, which mimics the thermal component of fever. The number of LCs and their morphology were analyzed at various time points up to 7 days after the initiation of WBH. The LCs of the ear epidermis were visualized using a fluorescein isothiocyanate-conjugated antibody specific for the major histocompatibility complex (MHC) class II molecule and confocal microscopy. Although MHC class II staining was diffuse on the surface of the LC body and dendritic extensions of both WBH and control samples, the WBH-treated LCs exhibited a more punctate morphology with fewer dendritic processes compared with control LCs. A significant decrease in the number of LCs was also observed 1 to 5 days after WBH treatment. Furthermore, in vitro heating of Balb/c ear skin cultures at 40 degrees C for 6 to 8 hours enhanced the numbers of viable LCs that migrated into the culture wells. These results suggest that WBH treatment stimulates epidermal LCs in the absence of foreign antigen.

Effect of Fever-Like Whole-Body Hyperthermia on Lymphocyte Spectrin Distribution, Protein Kinase C Activity, and Uropod Formation

Regional inflammation and systemic fever are hallmarks of host immune responses to pathogenic stimuli. Although the thermal element of fever is thought to enhance the activity of immune effector cells, it is unclear what the precise role of increased body temperatures is on the activation state and effector functions of lymphocytes. We report here that mild, fever-like whole body hyperthermia (WBH) treatment of mice results in a distinct increase in the numbers of tissue lymphocytes with polarized spectrin cytoskeletons and uropods, as visualized in situ. WBH also induces a coincident reorganization of protein kinase C (PKC) isozymes and increased PKC activity within T cells. These hyperthermia-induced cellular alterations are nearly identical with the previously described effects of Ag- and mitogen-induced activation on lymphocyte spectrin and PKC. Immunoprecipitation studies combined with dual staining and protein overlay assays confirmed the association of PKC beta and PKC theta with spectrin following its reorganization. The receptor for activated C kinase-1 was also found to associate with the spectrin-based cytoskeleton. Furthermore, all these molecules (spectrin, PKC beta, PKC theta, and receptor for activated C kinase-1) cotranslocate to the uropod. Enhanced intracellular spectrin phosphorylation upon WBH treatment of lymphocytes was also found and could be blocked by the PKC inhibitor bisindolylmaleimide I (GF109203X). These data suggest that the thermal element of fever, as mimicked by these studies, can modulate critical steps in the signal transduction pathways necessary for effective lymphocyte activation and function. Further work is needed to determine the cellular target(s) that transduces the signaling pathway(s) induced by hyperthermia.

Characterization of mild whole-body hyperthermia protocols using human breast, ovarian, and colon tumors grown in severe combined immunodeficient mice.

We have shown that one treatment of fever-like whole body hyperthermia (WBH) on mice bearing human breast tumors results in a tumor growth delay. Our goal was to repeat this study in mice bearing human ovarian or colon tumors. We further evaluated this WBH protocol by performing multiple and interrupted WBH treatments. Human tumors were grown in severe combined immunodeficient (SCID) mice. For WBH, core body temperatures were maintained at 39.8+/-0.2 degrees C for 6-8 hours. Multiple treatments were given 6-7 days apart. Interrupted WBH consisted of three 2-hour heatings, 15 minutes apart. Tumor growth time (TGT) was the number of days to grow 1.5 or 2 times in volume. For WBH-treated ovarian tumors, TGT was 12+/-1.2d, compared with 5.0+/-0.1d for untreated mice (P < 0.05). For colon tumors with one WBH treatment TGT was 4.4+/-1.1d. Two and three treatments had TGTs of 9+/-2.3d and 8+/-1.6d. For the untreated tumors, TGT was 2+/-0.7d (P < 0.01 for one, two, and three treatments). Histological examination indicated that one and two treatments were associated with cellular damage within the tumors. With a slower growing colon tumor, the TGT was 24+/-3.3d with three WBH treatments, compared with 14+/-1.8d for controls (P < 0.01). The TGT of breast tumors treated with interrupted WBH was not significantly different than the noninterrupted, with TGT of 7.3+/-0.8d and 6.2+/-1.0d, respectively. These data illustrate that WBH causes a tumor growth delay in mice bearing human ovarian and colon tumors. This response is enhanced with a second treatment of WBH. Interrupted and noninterrupted WBH give comparable anti-tumor results. We will continue to evaluate WBH in various animal models to optimize its potential for clinical administration and maximize the anti-tumor response.

Characterization of mild whole-body hyperthermia protocols using human breast, ovarian, and colon tumors grown in severe combined immunodeficient mice

We have shown that one treatment of fever-like whole body hyperthermia (WBH) on mice bearing human breast tumors results in a tumor growth delay. Our goal was to repeat this study in mice bearing human ovarian or colon tumors. We further evaluated this WBH protocol by performing multiple and interrupted WBH treatments.Human tumors were grown in severe combined immunodeficient (SCID) mice. For WBH, core body temperatures were maintained at 39.8+/-0.2 degrees C for 6-8 hours. Multiple treatments were given 6-7 days apart. Interrupted WBH consisted of three 2-hour heatings, 15 minutes apart. Tumor growth time (TGT) was the number of days to grow 1.5 or 2 times in volume.For WBH-treated ovarian tumors, TGT was 12+/-1.2d, compared with 5.0+/-0.1d for untreated mice (P < 0.05). For colon tumors with one WBH treatment TGT was 4.4+/-1.1d. Two and three treatments had TGTs of 9+/-2.3d and 8+/-1.6d. For the untreated tumors, TGT was 2+/-0.7d (P < 0.01 for one, two, and three treatments). Histological examination indicated that one and two treatments were associated with cellular damage within the tumors. With a slower growing colon tumor, the TGT was 24+/-3.3d with three WBH treatments, compared with 14+/-1.8d for controls (P < 0.01). The TGT of breast tumors treated with interrupted WBH was not significantly different than the noninterrupted, with TGT of 7.3+/-0.8d and 6.2+/-1.0d, respectively.These data illustrate that WBH causes a tumor growth delay in mice bearing human ovarian and colon tumors. This response is enhanced with a second treatment of WBH. Interrupted and noninterrupted WBH give comparable anti-tumor results. We will continue to evaluate WBH in various animal models to optimize its potential for clinical administration and maximize the anti-tumor response.