Background: Long-term fasting demonstrates greater therapeutic potential and broader application prospects in extreme environments than intermittent fasting. Method: This pilot study of 10-day complete fasting (CF), with a small sample size of 13 volunteers, aimed to investigate the time-series impacts on gut microbiome, serum metabolome, and their interrelationships with biochemical indices. Results: The results show CF significantly affected gut microbiota diversity, composition, and interspecies interactions, characterized by an expansion of the Proteobacteria phylum (about six-fold) and a decrease in Bacteroidetes (about 50%) and Firmicutes (about 34%) populations. Notably, certain bacteria taxa exhibited complex interactions and strong correlations with serum metabolites implicated in energy and amino acid metabolism, with a particular focus on fatty acylcarnitines and tryptophan derivatives. A key focus of our study was the effect of Ruthenibacterium lactatiformans, which was highly increased during CF and exhibited a strong correlation with fat metabolic indicators. This bacterium was found to mitigate high-fat diet-induced obesity, glucose intolerance, dyslipidemia, and intestinal barrier dysfunction in animal experiments. These effects suggest its potential as a probiotic candidate for the amelioration of dyslipidemia and for mediating the benefits of fasting on fat metabolism. Conclusions: Our pilot study suggests that alterations in gut microbiota during CF contribute to the shift of energy metabolic substrate and the establishment of a novel homeostatic state during prolonged fasting.

Hibernation, an adaptive mechanism to extreme environmental conditions, is prevalent among mammals. Its main characteristics include reduced body temperature and metabolic rate. However, the mechanisms by which hibernating animals re-enter deep sleep during the euthermic phase to sustain hibernation remain poorly understood. We selected the Tamias sibiricus as a model organism and conducted transcriptomic sequencing of its hypothalamus at multiple time points throughout hibernation. Through the strategies of gene set filtering and intersection analysis, we effectively filtered out redundant data, identifying a subset of genes whose expression was downregulated during the euthermic phase potentially inducing re-enter deep sleep, thereby maintaining the periodic cycles of torpor and arousal. These cycles are crucial for sustaining the overall hibernation process. Notably, genes associated with sodium and potassium ion channels were significantly enriched. Specifically, potassium ion-related genes such as Kcnc1, Kcna2, Kcng4, and Kcna6, along with sodium ion-related genes such as Scn1a and Hcn2, were markedly downregulated. qRT-PCR validation of four of these genes (Kcnc1, Kcna6, Scn1a, and Hcn2) confirmed significant downregulation during the euthermic phase compared to the deep sleep phase, further supporting our transcriptomic findings. This study provides novel insights into the hypothalamic transcriptome dynamics at various hibernation stages. Although the functional roles of these genes require further investigation, our findings lay the groundwork for future studies to elucidate the molecular mechanisms underlying hibernation.

This study aimed to evaluate the impact of prolonged fasting on the physiological and biochemical alterations and metabolic shifts in healthy adults and to provide experimental data and theoretical support for the hypometabolic state induced by prolonged fasting. Thirteen volunteers were selected through public recruitment to undergo a 21-day complete fasting experiment. The experimental period lasted 34 days, including a 3-day baseline, 21-day completing fasting, 5-day calorie restriction and 5-day full recovery diet. Physiological indicators such as body weight, blood pressure, blood glucose, blood ketones, and blood uric acid were evaluated along with resting metabolic rate, routine blood tests, liver function, and heart function indexes employing traditional approaches. During the 21-day complete fasting period, there was a significant decrease in body weight (average - 14.96 ± 1.55%), a reduction in blood glucose (average - 21.63 ± 0.058%), an increase in blood ketones (from baseline 0.1 ± 0.04 mmol/L to 6.61 ± 1.25 mmol/L) and blood uric acid (from baseline 385.38 ± 57.78 µmol/L to 866.31 ± 172.01 µmol/L), a continuous decline in resting energy expenditure (average - 20.3 ± 11.13%), and the respiratory quotient tending towards fat metabolism. Most of the items in the complete blood count and liver indicators remained stable and within the normal range. Heart function showed functional adaptive changes without structural damage. Prolonged fasting can reduce the body's resting energy expenditure and adapt to body weight loss through physiological regulatory mechanisms without adverse effects on basic physiological functions or the structure of important organs. Under medical supervision, healthy adults can safely engage in prolonged fasting for up to 21 days with metabolic adaption and no damage to pivotal organ, which could provide potential technical support for human health and survival strategies in extreme conditions such as food shortages during long-duration manned spaceflight.

为研究长期禁食过程中大鼠尿酸代谢的变化及其潜在的调控机制,以Sprague-Dawley(SD)大鼠为动物模型,通过病理组织切片、生化检测、荧光定量PCR(qRT-PCR)以及蛋白免疫印迹(Western blotting)等方法分析不同禁食时间(1,2,3,5,7天)大鼠尿酸水平及其代谢相关基因和蛋白的表达变化.结果表明,长期禁食未对大鼠肾脏组织产生明显的损伤,引起了血尿酸水平上升、尿尿酸水平波动性变化和血液尿酸酶活性升高;随着禁食时间的延长,主要尿酸转运蛋白的mRNA和蛋白表达水平逐渐上调.长期禁食过程中大鼠尿酸代谢变化可能与尿酸转运蛋白及尿酸酶活性有关.

Background The dense stroma of pancreatic ductal adenocarcinomas is a major barrier to drug delivery. To increase the local drug diffusion gradient, high doses of chemotherapeutic agent doxorubicin can be released from thermally-sensitive liposomes (ThermoDox®) using ultrasound-mediated hyperthermia at the tumour target. PanDox is designed as a Phase 1 single centre study to investigate enhancing drug delivery to adult patients with non-operable pancreatic ductal adenocarcinomas. The study compares a single cycle of either conventional doxorubicin alone or ThermoDox® with focused ultrasound-induced hyperthermia for targeted drug release. Methods Adults with non-resectable pancreatic ductal adenocarcinoma are allocated to receive a single cycle of either doxorubicin alone (Arm A) or ThermoDox® with focused ultrasound-induced hyperthermia (Arm B), based on patient- and tumour-specific safety conditions. Participants in Arm B will undergo a general anaesthetic and pre-heating of the tumour by extra-corporal focused ultrasound (FUS). Rather than employing invasive thermometry, ultrasound parameters are derived from a patient-specific treatment planning model to reach the 41 °C target temperature for drug release. ThermoDox® is then concurrently infused with further ultrasound exposure. Tumour biopsies at the targeted site from all patients are analysed post-treatment using high performance liquid chromatography to quantify doxorubicin delivered to the tumour. The primary endpoint is defined as a statistically significant enhancement in concentration of total intra-tumoural doxorubicin, comparing samples from patients receiving liposomal drug with FUS to free drug alone. Participants are followed for 21 days post-treatment to assess secondary endpoints, including radiological assessment to measure changes in tumour activity by Positron Emission Tomography Response Criteria in Solid Tumours ( PERCIST) criteria, adverse events and patient-reported symptoms. Discussion This early phase study builds on previous work targeting tumours in the liver to investigate whether enhancement of chemotherapy delivery using ultrasound-mediated hyperthermia can be translated to the stroma-dense environment of pancreatic ductal adenocarcinoma. If successful, it could herald a new approach towards managing these difficult-to-treat tumours. Trial registration ClinicalTrials.gov Identifier: NCT04852367 . Registered 21 st April 2022. EudraCT number: 2019–003950-10 (Registered 2019) Iras Project ID: 272253 (Registered 2019) Ethics Number: 20/EE/0284.

Background:Our previous studies found that high-intensity focused ultrasound (HIFU) stimulated tumor-specific T cells in a mouse H22 tumor model, and adoptive transfer of the T cells from HIFU-treated mice could subsequently elicit stronger inhibition on the growth and progression of the implanted tumors. The aim of this study was to investigate the mechanism of T cells from focused ultrasound ablation in HIFU-mediated immunomodulation.Methods:Sixty H22 tumor-bearing mice were treated by either HIFU or sham-HIFU, and 30 naïve syngeneic mice served as controls. All mice were euthanized on day 14 after HIFU and splenic T cell suspensions were obtained in each group. Using an adoptive cell transfer model, a total of 1 × 106 T cells from HIFU treated-mice were intravenously injected into each syngeneic H22 tumor-bearing mouse twice on day 3 and 4, followed by the sacrifice for immunological assessments at 14 days after the adoptive transfer.Results:T cells from HIFU-treated mice could significantly enhance the cytotoxicity of CTLs (p < 0.001), with a significant increase of TNF-α (p < 0.001) and IFN-γ secretion (p < 0.001). Compared to control and sham-HIFU groups, the number of Fas ligand+ and perforin+ tumor-infiltrating lymphocytes (TILs) and apoptotic H22 tumor cells were significantly higher (p < 0.001) in the HIFU group. There were linear correlations between apoptotic tumor cells and Fas ligand+ TILs (r = 0.9145, p < 0.001) and perforin+ TILs (r = 0.9619, p < 0.001).Conclusion:T cells from HIFU-treated mice can subsequently mediate cellular antitumor immunity, which may play an important role in the HIFU-based immunomodulation.

Background Fasting has been widely used to improve various metabolic diseases in humans. Adaptive fasting is necessary for metabolic adaptation during prolonged fasting, which could overcome the great advantages of short-term fasting. The liver is the main organ responsible for energy metabolism and metabolic homeostasis. To date, we lack literature that describes the physiologically relevant adaptations of the liver during prolonged fasting and refeeding. For that reason, this study aims to evaluate the response of the liver of Sprague-Dawley (SD) rats to prolonged fasting and refeeding. Methods Sixty-six male SD rats were divided into the fasting groups, which were fasted for 0, 4, 8, 12, 24, 48, 72, or 96 h, and the refeeding groups, which were refed for 1, 3, or 6 days after 96 h of fasting. Serum glucose, TG, FFA, β-hydroxybutyrate, insulin, glucagon, leptin, adiponectin and FGF21 levels were assessed. The glucose content, PEPCK activity, TG concentration and FFA content were measured in liver tissue, and the expression of genes involved in gluconeogenesis (PEPCK and G6Pase), ketogenesis (PPARα, CPT-1a and HMGCS2) and the protein expression of nutrient-sensing signaling molecules (AMPK, mTOR and SIRT1) were determined by RT-qPCR and western blotting, respectively. Results Fasting significantly decreased the body weight, which was totally recovered to baseline after 3 days of refeeding. A 4-day fast triggered an energy metabolic substrate shift from glucose to ketones and caused serum hormone changes and changes in the protein expression levels of nutrient-sensing signaling molecules. Glycogenolysis served as the primary fuel source during the first 24 h of fasting, while gluconeogenesis supplied the most glucose thereafter. Serum FFA concentrations increased significantly with 48 h of fasting. Serum FFAs partly caused high serum β-hydroxybutyrate levels, which became an important energy source with the prolongation of the fasting duration. One day of refeeding quickly reversed the energy substrate switch. Nutrient-sensing signaling molecules (AMPK and SIRT1 but not mTOR signaling) were highly expressed at the beginning of fasting (in the first 4 h). Serum insulin and leptin decreased with fasting initiation, and serum glucagon increased, but adiponectin and FGF21 showed no significant changes. Herein, we depicted in detail the timing of the metabolic response and adaptation of the liver to a 4-day water-only fast and subsequent refeeding in rats, which provides helpful support for the design of safe prolonged and intermittent fasting regimens.

Fasting shows great potential in preventing chronic diseases and has to be surmounted under some extraordinary circumstances. This study aimed to investigate the safety, time effects of metabolic homeostasis and health indexes during prolonged fasting. Thirteen participants were recruited to conduct a 10-day complete fasting (CF) in a controlled health research building under medical supervision including 3-day Baseline (BL), 10-day CF, 4-day calorie restriction (CR) and 5-day full recovery (FR). Body healthy status was assessed by surveying pulse, blood pressure, body weight (BW), blood glucose and ketones, body composition and nutritional and biochemistry indexes at different times. BW declined about 7.28 kg (−9.8%) after 10-day CF, accompanied by increased pulse and decreased systolic blood pressure, but there were no changes to the myocardial enzymogram. Body composition analysis showed fat mass was constantly lost, but lean mass could recover after CR. The energy substrate switch from glucose to ketone occurred and formed a stable dynamic balance between 3–6 days of CF. The lipid metabolism presented increased total cholesterol, LDL-C, ApoA1 and almost no changes to TG and HDL-C. Prolonged CF did not influence liver function, but induced a slight decrease of kidney function. The interesting results came from the marked increase of lipid-soluble vitamins and a significant decrease of sodium and chlorine. Adults could well tol-erate a 10-day CF. A new metabolic homeostasis was achieved. No vitamins but NaCl supplement should be considered. These findings provide evidence to design a new fasting strategy for clinical practice.

PURPOSE:To investigate whether phase-shift perfluoropetane (PFP) nanoemulsions can enhance pulsed high-intensity focused ultrasound (HIFU) ablation.METHODS:PFP was encapsulated by poly(lactic-co-glycolic acid) (PLGA) to form a nanometer-sized droplet (PLGA-PFP), which was added to an isolated perfused liver system. Meanwhile, phosphate-buffered saline (PBS) was used as a control. The perfused liver was exposed to HIFU (150 W, t = 3/5/10 s) at various duty cycles (DCs). The ultrasound images, cavitation emissions, and temperature were recorded. Rabbits with subcutaneous VX2 tumors were exposed to HIFU (150 W) at various DCs with or without PLGA-PFP. After ablation, necrosis volume and energy efficiency factor were calculated. Pathologic characteristics were observed.RESULTS:Compared to the PBS control, PLGA-PFP nanoemulsions markedly enhanced HIFU-induced necrosis volume in both perfused livers and subcutaneous VX2 tumor-bearing rabbits (P <.05). Inertial cavitation was much stronger in the pulsed-HIFU exposure at 10% than that in the continuous-wave HIFU exposure (P <.01). Peak temperature at 100% DC was significantly higher than that at 10% (P <.05). Compared to 100% DC HIFU exposure, the mean necrosis volume induced by 10 s exposure at 50% DC was significantly larger (P <.005) but lower at 10% DC in the isolated perfused livers (P <.05). In addition, the mean necrosis volume in subcutaneous VX2 tumor-bearing rabbits was significantly increased after HIFU exposure at 10% DC when compared to those at 100% DC (P <.05). Histopathologic analysis showed liquefaction necrosis in pulsed HIFU.CONCLUSION:PLGA-PFP nanoemulsions can enhance HIFU ablation in the isolated perfused livers and promote tumor ablation in the subcutaneous xenograft rabbit model. Appropriate pulsed HIFU exposure may increase the necrosis volume and reduce total ultrasound energy required for HIFU ablation.

High Intensity Focused Ultrasound (HIFU) capably bridges the disciplines of surgery, oncology and biomedical engineering science. It provides the precision associated with a surgical tool whilst remaining a truly non-invasive technique. Oxford has been a centre for both clinical and preclinical research in HIFU over the last twenty years. Research into this technology in the UK has a longer history, with much of the early research being carried out by Professor Gail ter Haar and her team at the Institute of Cancer Research at Sutton in Surrey. A broad range of potential applications have been explored extending from tissue ablation to novel drug delivery. This review presents Oxford's clinical studies and applications for the development of this non-invasive therapy. This includes treatment of solid abdominal tumours comprising those of the liver, kidney, uterus, pancreas, pelvis and prostate. It also briefly introduces preclinical and translational works that are currently being undertaken at the Institute of Biomedical Engineering, University of Oxford. The safety, wide tolerability and effectiveness of this technology is comprehensively demonstrated across these studies. These results can facilitate the incorporation of HIFU as a key clinical management strategy.

People may be unable to obtain anything edible for days under some circumstances, but they must maintain their calmness and cognition to navigate solutions. Our aim was to study changes in subjective sensations and cognition in healthy adults during a 10-day complete fasting experiment. Thirteen healthy male volunteers voluntarily participated in the 22-day experiment comprising 4 phases: 3 days of baseline consumption, 10 days of complete fasting (only water ad libitum), 4 days of calorie restriction, and a 5-day recovery period. The volunteers’ subjective sensations, cognitive performance, and serum energy substances were measured at 6 time points. Across the 6 time points, the trajectories of subjective sensations in response to fasting were “U”- or “ ∩ ”-shaped curves instead of progressive discomfort or mood enhancement. A significant fasting time effect was found on depression-dejection (baseline: 16.85 ± 2.88; highest score on the third day of completing fasting: 17.69 ± 3.97, P = 0.04) and self-rated anxiety (baseline: 26.23 ± 4.75; highest score on the sixth day of completing fasting: 30.85 ± 5.58, P = 0.01), and the change curves were consistent with the inflection point of the energy substrates shifting from serum glucose to ketone. In addition, basic cognitive functions appeared to be unaffected during the 10-day fast. Our study showed strong influences on the sensations from the third to sixth days of the prolonged fasting period but no significant effects on basic cognitive abilities associated with the energy substance switch. These findings could contribute to the development and understanding of survival strategies in food-shortage emergencies or of intermittent fasting programmes.

This study aims to investigate the feasibility of quantitative ultrasonic backscatter in evaluating human cortical and trabecular bone densities in vivo based on a head-down-tilt bed rest study, with 36 participants tested through 90 d of bed rest and 180 d of recovery. Backscatter measurements were performed using an ultrasonic backscatter bone diagnostic instrument. Backscatter parameters were calculated with a dynamic signal-of-interest method, which was proposed to ensure the same ultrasonic interrogated volume in cortical and trabecular bones. The backscatter parameters exhibited significant correlations with site-matched bone densities provided by high-resolution peripheral quantitative computed tomography (0.33 < |R| < 0.72, p < 0.05). Some bone densities and backscatter parameters exhibited significant changes after the 90-d bed rest. The proposed method can be used to characterize bone densities, and the portable ultrasonic backscatter bone diagnostic device might be used to non-invasively reveal mean bone loss (across a group of people) after long-term bed rest and microgravity conditions of spaceflight missions.

Lyso-thermosensitive liposomes (LTSLs) are specifically designed to release chemotherapy agents under conditions of mild hyperthermia. Preclinical studies have indicated that magnetic resonance (MR)-guided focused ultrasound (FUS) systems can generate well-controlled volumetric hyperthermia using real-time thermometry. However, high-throughput clinical translation of these approaches for drug delivery is challenging, not least because of the significant cost overhead of MR guidance and the much larger volumes that need to be heated clinically. Using an ultrasound-guided extracorporeal clinical FUS device (Chongqing HAIFU, JC200) with thermistors in a non-perfused ex vivo bovine liver tissue model with ribs, we present an optimised strategy for rapidly inducing (5–15 min) and sustaining (>30 min) mild hyperthermia (ΔT <+4°C) in large tissue volumes (≤92 cm3). We describe successful clinical translation in a first-in-human clinical trial of targeted drug delivery of LTSLs (TARDOX: a phase I study to investigate drug release from thermosensitive liposomes in liver tumours), in which targeted tumour hyperthermia resulted in localised chemo-ablation. The heating strategy is potentially applicable to other indications and ultrasound-guided FUS devices.

Objective To evaluate the middle-term efficacy and complications of ultrasound-guided high intensity focused ultrasound (USgHIFU) for the treatment of symptomatic uterine fibroids in an NHS population. Methods A prospective observational single-center study at a single university hospital in Oxford, UK. Patients with symptomatic uterine fibroids who declined standard surgical/radiological intervention and were referred to the HIFU unit were considered for USgHIFU treatment. Clinical evaluation, adverse event monitoring, uterine fibroid symptoms and health-related quality of life questionnaire (UFS-QOL) and contrast-enhanced pelvic magnetic resonance imaging (MRI) were performed before and at regular intervals after treatment to assess patient outcome. Results 12 of 22 referred patients underwent one session of USgHIFU ablation of 14 fibroids overall and received a twoyear follow-up. No serious adverse events were reported, but a second-degree skin burn was observed in one patient who had a surgical scar from a previous caesarean section. Mean symptom severity scores (SSS-QOL) improved significantly from 56.5 +/- 29.1 (SD) at baseline to 33.4 +/- 23.3 (p < 0.01) at three months, 45.0 +/- 35.4 (p < 0.05) at one year and 40.6 +/- 32.7 (p < 0.01) at two years post-treatment. The mean nonperfused volume ratio was 67.7 +/- 39.0 % (SD) in the treated fibroids (n = 14) within three months of treatment. The mean volume reduction rates of the treated fibroids were 23.3 +/- 25.5 % (SD) at 3 months post-treatment (p < 0.01, n = 14), 49.3 +/- 23.7 % at 12 months (p < 0.05, n = 8), and 51.9 +/- 11.1 % at 24 months (p < 0.005, n = 8). Conclusion This study demonstrates the clinical efficacy of USgHIFU ablation of uterine fibroids and the low risk of complications. We believe that this noninvasive approach may offer an alternative therapy for women with symptomatic uterine fibroids. While HIFU is fast becoming the standard of care for fibroid ablation in other countries, to our knowledge, this study is the first to present clinical experience of US- guided HIFU ablation of symptomatic uterine fibroids in an NHS population.