Effect Of Whole-body Hyperthermia Research Articles

Abstract 3517: Use of a novel synthetic biomaterial to induce mild whole body hyperthermia for the treatment of cancer in a preclinical model

Abstract Hyperthermia is currently being investigated as an alternative form or cancer therapy. Numerous basic and pre-clinical published reports have shown the antitumor effects of hyperthermia in various cancer models. High temperatures, low duration (heat shock) will have a direct killing effect on exposed cells. The limitation to this approach is the restriction of tumor location and associated side effects. Low temperature, high duration whole body hyperthermia (WBH) is generally considered to be the least toxic but requires long exposures that are generally uncomfortable or inconvenient to the patients. In the present study, we show the efficacy of a synthetic far-infrared emitting biomaterial to induce and evaluate its therapeutic potential when used alone or in combination with chemotherapy. We used BioRubber (BR, Yamamoto Bio-Technology Inc., Anaheim, CA), a state of the art biomaterial that emits far infrared radiation in the 4-25 μm spectral ranges. To determine the efficacy to induce mild whole body hyperthermia, athymic nude mice were house in BR lined cages. Core body temperatures of mice housed in BR-lined cages were significantly higher than mice housed in unlined cages and were maintained up to 2 weeks during continuous exposure (37.70oC vs. 36.75oC, p=0.038, respectively.). To determine the antitumor effects of WBH, KU7/GFP-bearing nude mice were housed in cages lined with BR for 28 days. Non-significant tumor growth inhibition was observed in tumors of mice housed in BR. Histological and immunohistochemical analysis revealed increased granulocyte activity in tumors of BR-exposed mice. Additionally, increased levels of C-GSF, GM-CSF, TNFα and IL-12p70 corresponded to exposure to WBH. To determine the long term safety and efficacy of mild WBH and chemotherapy in deep tumors, we carried out a survival study using immunodeficient mice orthotopically inoculated with KU7/GFP cells and treated doxorubicin (Dox) alone or in combination with BR. Although no treatment efficacy was observed in mice treated with BR with regards to tumor size (tumor size according to the expression of GFP was 350.5, 309.7, 357.4, 257.3 for control, WBH, Dox and WBH/Dox groups, respectively), survival was improved for mice exposed to BR. Survival rates were 50% (5/10), 70% (7/10), 10% (1/10) and 50% (5/10), for control, WBH, Dox and WBH/Dox groups, respectively. It is unclear if mild WBH has a direct antitumor effect; however, it appears that BR-induced mild WBH may be capable of inducing immuno-stimulatory that may improve survival in a preclinical model. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3517. doi:1538-7445.AM2012-3517

Abstract 806: Anti-tumor effects of low temperature whole body hyperthermia on human bladder cancer cells in vivo

Abstract As a whole, the concept of thermotherapy is still under study. However, there is an abundant amount basic and pre-clinical published reports that have shown the antitumor effects of hyperthermia in various cancer models. Local, regional and whole body hyperthermia (WBH) has been studied and the effectiveness of the treatment depends largely on the temperature achieved and the duration of treatment. High temperatures, low duration (heat shock) will have a direct killing effect on exposed cells. The limitation to this approach is the restriction of tumor location. Low temperature, high duration WBH is generally considered to be the least toxic but requires long exposures that are generally uncomfortable or inconvenient to the patients. In this study we investigate the therapeutic efficacy of a synthetic far-infrared emitting biomaterial (BR), capable of inducing mild whole body hyperthermia, alone or in combination with chemotherapy against bladder cancer cell lines in vivo. Immunocompetent and immunodeficient mice were inoculated with a human superficial bladder cancer cell (KU7/GFP) or mouse bladder cancer cell (NBT2), respectively, and treated with BR alone or in combination with doxorubicin (Dox). Mice exposed to BR increased their core body temperature by 1oC (P<0.05) after 2 weeks of exposure. Both immunocompetent and immunodeficient bearing subcutaneous tumor xenografts treated to WBH demonstrated a clear tendency in the reduction of tumor size. Histological analysis showed that tumors exposed to WBH had remarkable granulocyte infiltration accompanied by increased necrosis. Elevated levels of HSP27, HSP70 and HSP90 were detected in tumors of mice exposed to WBH. Increased levels of C-GSF, GM-CSF, TNFα and IL-12p70 corresponded to exposure to WBH. To determine the synergistic effects of WBH and chemotherapy, a survival study was carried out using immunodeficient mice orthotopically inoculated with KU7/GFP cells. Mice treated with Dox or WBH/Dox demonstrated a reduction in tumor size compared to mice treated with WBH and untreated controls. More interestingly, survival rates for control, WBH, Dox and WBH/Dox groups were 50% (5/10), 70% (7/10), 10% (1/10) and 50% (5/10), respectively. No clear differences were noted in HSP expression or granulocyte infiltration in these mice. Our data suggests that WBH may induce mild antitumor effects; although, the precise mechanism is still unclear, it appears that it may be due to an immuno-stimulatory effect. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 806. doi:10.1158/1538-7445.AM2011-806

Abstract 5492: The effects of whole body hyperthermia on tumor growth by a novel far infrared emitter

Abstract Whole body hyperthermia (WBH) has been used alone or as an adjunct to radio- and/or chemotherapy for the treatment of various malignant diseases. The therapeutic effect of WBH in these conditions has been hypothesized to involve direct or indirect activation of the immune system and heat shock proteins (HSPs). In this study, we investigate the effects of hyperthermia in vitro and in vivo using BioRubber (BR, Yamamoto Bio-Technology Inc., Anaheim, CA), a revolutionary far infrared emitter on tumor growth. BR is a pliable state-of-the-art biomaterial that emits FIR in the 4-25μm spectral ranges. For the in vitro experiments, cell growth assays and cell cycle analysis was performed in a total of twelve different cancer cell lines (HeLa, bladder, prostate and renal) sandwiched between BR. BR had no inhibitory effects on any of the tumor cells grown in vitro. To determine the effects of BR therapy on tumor and normal tissue in vivo, KU7/GFP-bearing nude mice were housed in cages lined with BR for 28 days. Tumor size and core body temperature were recorded weekly. The core body temperatures of mice exposed to BR increased significantly by 1oC (P<0.05) after 2 weeks of exposure to BR. Although not significant, tumors of mice exposed to BR showed a clear tendency in tumor size reduction. Tumors were collected and anlyzed for histopathology, TUNEL and PCNA immunohistochemical analysis. Proliferation and apoptotic rates in tumors from mice exposed to BR were similar to control mice. Further histopathological analysis showed that BR-exposed tumors had remarkable granulocyte infiltration accompanied by increased necrosis. This suggest that BR exposure was indeed able to induce and sustain mild hyperthermia in vivo with reduced tumor growth. However, no direct inhibitory on the tumor cells resulted form BR-induced hyperthermia but rather appeared to have been an indirect effect of immuno-stimulation achieved from sustained WBH. To further investigate the immunological component of hyperthermia-induced immune response, a syngeneic tumor model was carried out using mouse RENCA cells in immunocompetent and immunodeficient mice. Similar tumor growth inhibitory effects were seen in both immunocompetent and immunodeficient mice thus suggesting an innate immune response as a result of sustained WBH. Together, these data suggest that BR may be a promising biomaterial in for use hyperthermia therapy: however, more research has to be conducted to elucidate the specific mechanisms involved in immuno-stimulation and whether the effects from BR-induced hyperthermia can be maximized with combination therapies. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5492.

Whole-body hyperthermia attenuates rat experimental autoimmune encephalomyelitis

Hyperthermia has been known to induce transient expression of 27 kDa heat shock protein (HSP27) in several types of cells in the central nervous system Little is known about the effects of whole-body hyperthermia in the pathogenesis of experimental autoimmune encephalomyelitis (EAE) in the rat. The aim of this study was to examine whether whole body hyperthermia affect the clinical symptoms of EAE in rats. EAE was induced in Lewis rats that were immunized with guinea pig myelin basic protein (MBP)and complete Freund’s adjuvant. At 7 days after immunization, the immunized rats were divided into three groups including placed into a 42t incubator for 10 minutes, for 20 minutes and room temperature. The onset, severity, and duration of EAE paralysis in the whole body hyperthermia treated groups in the day 7 Pl-treated rats were significantly delayed, suppressed, and reduced, respectively, compared with those of the EAE control group. Moreover, the clinical amelioration coincided with decreased infiltration of inflammatory cells in the EAE-affected spinal cord. Collectively, whole body hyperthermia has shown to reduce paralysis in EAE, an animal model of human demyelinalin9 diseases.

Antitumor effect of whole body hyperthermia with α-galactosylceramide in a subcutaneous tumor model of colon cancer

Aim: Whole body hyperthermia (WBH) has been used clinically as an adjunct to radio- and chemotherapy in patients with various cancers. Recently, it has been reported that an activation of the immune system has recently been reported as a possible contributor to the therapeutic effects of WBH. Conversely, the glycolipid α-galactosylceramide (α-GalCer) is recognized by natural killer (NK) T cells together with the monomorphic MHC-like antigen, CD1d, in mice and humans. This study investigated the antitumor effects of WBH combined with α-GalCer in a mouse subcutaneous tumor model of colon cancer.Methods: Colon26 cells were inoculated subcutaneously into male BALB/c mice to establish subcutaneous tumor. Colon26-bearing mice were treated with WBH using far infrared rays three times/week. Rectal temperature was maintained for 60 min at 41°C. In some experimental groups, α-GalCer was intraperitoneally injected before WBH. We investigated the therapeutic effects of WBH, α-GalCer and combined therapy.Results: (1) Compared with controls, WBH alone resulted in significant inhibition of tumor growth. (2) No inhibitory effect on tumor growth was seen with α-GalCer. (3) The combination of WBH and α-GalCer showed significant inhibition of tumor growth and prolongation of survival. (4) Serum IFN-γ increased after 3 h and returned to basal levels by 24 h after α-GalCer administration. (5) CTL activity was enhanced following combination therapy with WBH and α-GalCer.Conclusion: WBH showed antitumor effects in a mouse subcutaneous tumor model of colon cancer. Addition of α-GalCer increased the efficacy of WBH, probably via enhancement of immune response.

Effects of whole-body hyperthermia on human anti-tumor immunity

热疗已经成为继手术、放疗、化疗和生物治疗之后又一重要的肿瘤治疗手段.全身热疗(WBH)的治疗机制目前还不完全清楚,但其治疗效果已被假设归因于免疫系统的激活.热疗效果不仅在于高热直接杀死肿瘤细胞,机体免疫状态的激活也对消灭肿瘤细胞起着重要作用。

Differential gene expression in peripheral blood lymphocytes of cancer patients treated with whole body hyperthermia and chemotherapy: A pilot study

Purpose: The effect of whole body hyperthermia (WBH) at 41.8–42°C on the cellular immune system is still poorly investigated. The aim of this study was to identify genes that become upregulated in peripheral blood lymphocytes (PBLs) of cancer patients during a combined treatment with WBH and chemotherapy by generating complex arrays of cDNA.Methods: PBLs were obtained from four patients with different malignancies treated with WBH and varying cytostatic schedules before treatment and immediately thereafter. After constructing subtracted cDNA libraries, clones were screened for cDNA induction by dot-blot and semi-quantitative RT-PCR (sq-RT-PCR).Results: Among 192 clones, 39 cDNAs were significantly upregulated. Sequencing revealed three groups of genes for which upregulation of mRNA was confirmed by sq-RT-PCR. The first group consisted of genes encoding for various heat shock proteins (HSP 60, 90a, 90b, 105). Further sq-RT-PCR demonstrated differential expression of HSP27 and HSP70 as well. The second group (calcyclin-binding-protein, haemoglobin-beta-chain) comprised genes without pre-specified association to hyperthermia. The cDNA encoding macrophage-inflammatory-protein-1-beta was also observed and may be associated with the pre-described activation of lymphocyte sub-populations during WBH.Conclusion: Treatment with WBH and chemotherapy elicits significant short-term effects on the expression of a variety of genes responsible for cellular integrity, stimulation and migration of immune effector cells. Further investigation is warranted to more clearly define the role of those genes for the clinical effect of WBH.

Circulatory and biochemical effects of whole body hyperthermia.

Abstract The physiological effects of whole body hyperthermia to 42 C° have been studied in 12 subjects. There was a sustained increase in the heart rate and an initial increase in the arterial and central venous pressures. Sweat and electrolyte losses were high. The serum bilirubin remained normal if the temperature did not exceed 41.8 C°. Above this temperature the serum enzymes lactate dehydrogenase, alanine aminotransferase and aspartate aminotransferase rose, as did the serum bilirubin. While the latter effect might be due to liver damage, it could also be related to thermal destruction of red cells. A leucocytosis develops during the hyperthermic state.

Patients with solid tumors treated with high-temperature whole body hyperthermia show a redistribution of naive/memory T-cell subtypes

An activation of the immune system might contribute to the therapeutic effect of whole body hyperthermia (WBH) in cancer patients. We explored immune and endocrine responses in patients undergoing high-temperature WBH. Identical parameters were investigated in a separate group of healthy volunteers undergoing physical exercise to rule out effects of sympathetic activation. Lymphocyte subpopulations, lymphocytic expression of a range of adhesion molecules, and serum concentrations of a variety of hormones and cytokines were assessed in cancer patients undergoing high-temperature (60 min at 41.0-41.8 degrees C) WBH (n = 25) and in a separate group of healthy volunteers (n = 10) performing strenuous physical exercise. WBH induced an increase in human growth hormone (hGH), ACTH, and cortisol as well as in TNF-alpha, IL-6, IL-8, and IL-12R. We observed an increase in natural killer (NK) cells and CD56+ NK T cells shortly after initiation of WBH. In contrast, we found a decrease in T cells expressing L-selectin (CD62L) or alpha4beta7 integrin adhesion molecules mediating homing to lymphatic tissues. Accordingly, we observed a decrease in CD45RA+CCR7+ naive and CD45RA-CCR7+ central memory T cells. Numbers of CD45RA-CCR7- memory effector and CD45RA+CCR7 terminally differentiated T cells, on the other hand, remained unchanged. No comparable changes were observed in the group of healthy volunteers. In conclusion, patients with solid tumors treated with WBH show an increase in NK and NK T cells. In a later phase, plasma concentrations of IL-8, hGH, and cortisol increase, correlated with an influx of neutrophils into the peripheral blood. The alterations in T-cell populations suggest that WBH may induce naive and central-memory T cells to enter lymphatic tissue to await antigen exposure and effector T cells to migrate into peripheral tissues to exert their effector function. Although the exercise group may not be an appropriate control to proof the effect of WBH, these changes were not seen in the healthy volunteers performing physical exercise.

Reduced voluntary activation of human skeletal muscle during shortening and lengthening contractions in whole body hyperthermia

This study examined the effect of whole body hyperthermia on the voluntary activation of exercised and non-exercised skeletal muscle performing a series of lengthening and shortening contractions. Thirteen subjects exercised on a cycle ergometer at 60% of maximal oxygen consumption until voluntary exhaustion in ambient conditions of approximately 40 degrees C and 60% relative humidity. Before and immediately following the cycle protocol, subjects performed a series of 25 continuous isokinetic shortening and lengthening maximal voluntary contractions (MVCs) of the leg extensors and forearm flexors. Voluntary activation for shortening and lengthening contractions for the forearm and leg was assessed prior to and following the 25 MVCs by superimposing a paired electrical stimulus to the femoral nerve and the biceps brachii during additional MVCs. Exercise to exhaustion increased rectal temperature to 39.35+/-0.50 degrees C. Voluntary activation remained unchanged following the prehyperthermia endurance set of shortening and lengthening maximal contractions in both the forearm flexors and leg extensors. Similarly, voluntary activation remained at prehyperthermic levels for the single MVCs immediately following the cycle trial. However, by the time of completion of the posthyperthermia endurance contractions, voluntary activation had declined significantly by 5.87+/-7.56 and 8.46+/-9.26% in the shortening and lengthening phases, respectively, for the leg extensors but not for the forearm flexors. These results indicate that the central nervous system (CNS) reduces voluntary drive to skeletal muscle performing both shortening and lengthening contractions following exercise-induced hyperthermia. The reductions in voluntary activation were only observed following a series of dynamic movements, indicating that the CNS allows for initial and brief 're-activation' of skeletal muscle following exercise-induced hyperthermia.

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.

Cerebral oxygen extraction and autoregulation during extracorporeal whole body hyperthermia in humans.

The effects of hyperthermia on the human brain are incompletely understood. This study assessed the effects of whole body hyperthermia on cerebral oxygen extraction and autoregulation in humans. Nineteen patients with chronic hepatitis C virus infection, not responding to interferon treatment, were subjected to experimental therapy with extracorporeal whole body hyperthermia at 41.8 degrees C for 120 min under propofol anesthesia (23 sessions total). During treatment series A (13 sessions), end-tidal carbon dioxide was allowed to increase during heating. During series B (10 sessions), end-tidal carbon dioxide was maintained approximately constant. Cerebral oxygen extraction (arterial to jugular venous difference of oxygen content) and middle cerebral artery blood flow velocity were continuously measured. Cerebral pressure-flow autoregulation was assessed by static tests using phenylephrine infusion and by assessing the transient hyperemic response to carotid compression and release. For treatment series A, cerebral oxygen extraction decreased 2.2-fold and cerebral blood flow velocity increased 2.0-fold during heating. For series B, oxygen extraction decreased 1.6-fold and flow velocity increased 1.5-fold. Jugular venous oxygen saturation and lactate measurements did not indicate cerebral ischemia at any temperature. Static autoregulation test results indicated loss of cerebrovascular reactivity during hyperthermia for both series A and series B. The transient hyperemic response ratio did not decrease until the temperature reached approximately 40 degrees C. Per degree Celsius temperature increase, the transient hyperemic response ratio decreased 0.07 (95% confidence interval, 0.05-0.09; P = 0.000). This association remained after adjustment for variations in arterial partial pressure of carbon dioxide, mean arterial pressure, and propofol blood concentration. Profound hyperthermia during propofol anesthesia is associated with decreased cerebral oxygen extraction, increased cerebral blood flow velocity, and impaired pressure-flow autoregulation, indicating transient partial vasoparalysis.

Whole-body hyperthermia in combination with platinum-containing drugs in patients with recurrent ovarian cancer.

Patients with advanced ovarian cancer have an enormous risk of relapse after primary therapy, and the prognosis for these patients remains bleak. Primary and acquired resistance of tumor cells to antineoplastic drugs is a major cause of the limited effectiveness of chemotherapy. The effect of whole-body hyperthermia (WBH) combined with platinum-containing chemotherapy in the treatment of recurrent ovarian cancer was examined in this study. Patients studied were those with pathologically verified epithelial ovarian cancer after operation who had had first-line chemotherapy with cisplatin or carboplatin, and relapsed. All 21 patients were treated with WBH and platinum-based chemotherapy. During the WBH, a core temperature of 41.5 degrees C-42 degrees C was attained in the rectum. We combined the WBH with 300-400 mg/dl artificial hyperglycemia. The plateau temperature was held over a period of, on average, 90 +/- 30 min, and the artificial hyperglycemia, on average, 240 +/- 30 min. WBH was repeated at the beginning of each new chemotherapy cycle. One patient (4.8%) had a complete remission, 7 patients (33.3%) had a partial remission, stable disease was noted in 10 patients (47.6%), and 3 (14.3%) patients did not respond and had progressive disease. Median time to progression was 6.5 months, and median survival time, 16.5 months. Our results validate the efficacy of WBH in the treatment of patients with recurrent platinum-resistant ovarian cancer. The overall tolerance of this treatment was good. The priority for all patients was an improvement in life quality; this was seen 3-4 days after WBH. The encouraging results should be confirmed in randomized studies. Patients with advanced ovarian cancer have an enormous risk of relapse after primary therapy, and the prognosis for these patients remains bleak. Primary and acquired resistance of tumor cells to antineoplastic drugs is a major cause of the limited effectiveness of chemotherapy. The effect of whole-body hyperthermia (WBH) combined with platinum-containing chemotherapy in the treatment of recurrent ovarian cancer was examined in this study.

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.

Whole body hyperthermia preserves endothelial function and restores mesenteric blood flow after resuscitated hemorrhage

Endothelial dysfunction has been implicated in regional blood flow deficits after resuscitated shock. Whole body hyperthermia generates heat shock proteins (HSP) that attenuate protein denaturation and preserve cellular function. This study was performed to determine the effect of whole body hyperthermia on endothelial function and mesenteric blood flow after resuscitated hemorrhage. Sprague Dawley rats were hemorrhaged to 30% of blood volume and resuscitated with shed blood and an equal of volume of Ringer’s Lactate (Standard Resuscitation, SR). Intravital microscopy was used to determine first order arteriolar (A1) diameters and blood flow (QA1) in the neurovascularly intact ileum at baseline and 90 minutes post resuscitation (T90). Animals treated with SR and whole body hyperthermia (SR-H) were placed into a ventilated heating chamber following hemorrhage and resuscitation to achieve a temperature of 39.5–40°C for 6 hours. Identical microvascular studies were performed 18 hours later. Endothelial function was quantitated by measuring changes in vessel diameter to topical application of the endothelial dependent dilator acetylcholine (Ach, 10−5 M). A1 diameter is reported in microns and QA1 as nanoliters per second (+/− SEM). Tissue was taken from the ileum for HSP72 determination via Western analysis. This study demonstrated that whole body hyperthermia applied after resuscitated hemorrhage results in an upregulation of HSP expression that is associated with preserved endothelial function and restoration of mesenteric blood flow. These results suggest that whole body hyperthermia may serve as an adjunct to standard resuscitation in restoring blood flow and attenuating subsequent organ dysfunction.TABLE—ABSTRACT 19AchQA1HSP72BaselineSR85 ± 5161 ± 15.124 ± .1SR-H90 ± 5226 ± 17.124 ± .1T90SR48 ± 831 ± 7.241 ± .1SR-H88 ± 5∗157 ± 20∗.924 ± .2∗∗P = <0.05 vs. T90 SR for ACH, QA1 and HSP72 by Student’s t test.

The effect of whole-body hyperthermia combined with 'metronomic' chemotherapy on rat mammary adenocarcinoma metastases

Many women diagnosed with invasive breast cancer have undetected occult metastases at the time of their primary tumour diagnosis. The development and growth of these micro-metastases relies heavily on angiogenesis. Therefore, administering an angiogenesis-blocking treatment from the time of diagnosis could reduce the incidence of metastasis and, ultimately, increase patient survival. It is hypothesized that an antiangiogenesis strategy combining fever-range whole-body hyperthermia (FR-WBH) and metronomic chemotherapy could inhibit the development of metastatic disease with minimal toxicity. To test this theory, a low, daily dose of the topoisomerase-I inhibitor irinotecan hydrochloride (CPT-11) was administered over a prolonged period of time to rats bearing the highly metastatic MTLn3 mammary adenocarcinoma primary tumour surgically excised on day 12 after implantation. The metronomic CPT-11 was combined with long-duration, low-temperature, fever-range whole body hyperthermia (FR-WBH). This systemic hyperthermia enhances chemotherapy-induced cytotoxicity as well as immunological activity. Both the group treated with FR-WBH alone and the combined FR-WBH+CPT-11 group had delayed onset and reduced incidence of axillary lymph node metastases compared to control ( p < 0.05). Combination therapy of FR-WBH+CPT-11 resulted in a significantly greater inhibition of axillary lymph node metastasis volume compared to both control and CPT-11 alone ( p < 0.02) at day 16. Interestingly, none of the therapies significantly affected inguinal lymph node metastases. Lung metastases were decreased by 36% at the time of death in rats treated with FR-WBH+CPT-11, by 25% in the CPT-11 alone group and by 14% in the FR-WBH alone group. Rats treated with FR-WBH, + CPT-11 survived significantly longer (35%) than control animals ( p < 0.04). Neither significant body weight loss nor gastrointestinal toxicity was observed in any group. These data suggest that, after excision of the primary tumour, FR-WBH and metronomic CPT-11 can be safely combined to reduce distant lymph node and lung metastases and, thus, to increase survival.

Effect of Whole Body Hyperthermia on Ischemia and Reperfusion Injury of Rat Intestine: Real-Time ATP Change Studied Using 31P-MRS

We studied the effect of hyperthermia pretreatment on subsequent small intestinal ischemia and reperfusion (I/R) injury in the rat. Systemic hyperthermia has been reported to induce heat shock proteins (HSPs) in several organs [1-6]. We examined the expression of HSP72 in the small intestinal mucosa using Western blotting and immunohistochemistry. We monitored energy metabolism using magnetic resonance spectroscopy continuously during a 60-min ischemia and the following 120 min of reperfusion. Expression of HSP72 in the small intestine was significantly increased at 6–8 h after hyperthermia. Intestinal ischemia was induced by clamping the superior mesenteric artery. Heating of the rat conferred substantial resistance to the I/R injury. In the untreated rats, β-ATP decreased during ischemia (37.1 ± 15.5% of the pre-ischemic value) and recovered on reperfusion, but reached only ∼50% of the pre-ischemic value after 120 min of reperfusion. However, β-ATP in the pretreated rats was maintained during ischemia at significantly higher levels and on reperfusion reached ∼80% of the pre-ischemic value. These results indicate that hyperthermia protects the rat intestine from the I/R injury by unknown mechanisms which may include the induction of HSPs.

Whole Body Hyperthermia Accelerates Atherogenesis in Low-Density Lipoprotein Receptor Deficient Mice

The application of brief periods of heat stress prior to induction of various forms of tissue injury (ischemia-reperfusion, myocardial infarction, endothelial denudation) has been shown to result in preconditioning and attenuation of subsequent damage. Atherosclerosis represents a state of heightened response to injury at the level of the vessel wall, involving endothelial cells, smooth muscle cells, and macrophages. In the current study, we studied the effects of whole body hyperthermia (WBH) on diet-induced atherosclerosis in a murine model. Low-density lipoprotein receptor deficient mice were either exposed to a 30-min WBH (n = 10) or nontreated (n = 7). Animals were given a high-fat (“Paigen”-type) diet to speed the progression of atherosclerosis immediately following WBH for 6 weeks. Aortic and plaque heat shock protein (HSP) 70, suggested to mediate thermotolerance, was assessed by immunohistochemisry and Western blot at different time points following induction of WBH. Aortic sinus plaque formation was significantly accelerated in WBH-treated mice (275,800 ± 19,540 μm2 ) in comparison with their control litters (152,100 ± 18,200 μm2 ; P = 0.0004). Plaque composition was also influenced by WBH as lesions were more mature and had an increased proportion of lipid core/fibrous cap accompanied by increased numbers of apoptotic cells. Total cholesterol and triglyceride levels were not affected significantly by WBH. HSP70 protein expression in the aortas was increased 30 min and 6 and 12 h following WBH induction. Thus, induction of WBH, which affords protection in models of arterial injury, appears to have a proatherogenic role in murine atherosclerosis, despite its upregulatory influence on the expression of HSP70.

Effect of whole body hyperthermia on radiation therapy of transplanted fibrosarcoma in Swiss mice

The exposure of normal mice to whole body hyperthermia (1h WBH at 39 or 40°C), 20 or 48h prior to total body irradiation (TBI) with lethal doses of n -rays affords significant protection as assessed by survival. The radioprotective effect of WBH, as observed in normal mice, diminished in tumour bearing mice depending upon the size of tumour. Treatment of tumour bearing mice with mild WBH, 20h prior to local irrradiation (LIR), did not protect the transplanted tumour against radiotherapy with a single dose of 20Gy or fractionated dose (in five fractions) of 7.5Gy on alternate days. In fact, mild WBH treatment enhanced the tumour regression and increased the mean survival time after fractionated dose therapy. However, the prior mild WBH was found to be ineffective in protecting normal tissue, as assessed by skin contraction after local irradiation (50Gy). This indicates that mild WBH treatment given 20 h prior to local radiotherapy enhances fibrosarcoma tumour regression but cannot protect skin (normal tissue) against local irradiation. It appears that radioprotection of animals by WBH may be the consequence of its radioprotective effect on haemopoietic tissues mediated through certain cytokines. Perhaps WBH may not have a radioprotective effect on other tissues, as evident from skin contraction studies.

Effects of whole-bodyhyperthermia on the canine central nervous system

It has been reported that central nervous system (CNS) tissue may be more heat labile than other tissues of the body. However, no definite information has been available on how much heat CNS tissue can tolerate without sustaining damage during whole-body hyperthermia, especially in a chronic stage. In this study, whole-body hyperthermia was induced in dogs by extracorporeal heating of blood, to determine the effects 7 days after hyperthermia on the canine brain and spinal cord. The temperatures of both the brain and the spinal cord were raised to 42.0 0.1oC and maintained at that level for 60min. Seven days later, all of the dogs were sacrificed by transcardial perfusion using 10% formaldehyde phosphate buffer for microscopic examination. The thermal dose resulted in neither microscopic damage to the CNS nor neurological symptoms, as determined by comparison of microscopic and neurological findings with those of dogs whose brain and spinal cord temperatures were maintained at 37.0oC for 60min. The findings suggest that, for medical purposes, whole-body hyperthermia appears promising for application at a thermal dose of up to 42.0oC for 60min.