Hyperbaric oxygen therapy and cancer--a review

Hyperbaric oxygen therapy as an adjunt treatment for glioma and brain metastasis: a literature review

The incidence and mortality rates of malignant tumors are increasing annually, with gliomas and brain metastases linked to a poor prognosis. Hyperbaric oxygen therapy is a promising treatment modality for both gliomas and brain metastases. It can alleviate tumor hypoxia and enhance radiosensitivity. When combined with other treatments for gliomas, this therapy has the potential to enhance survival rates. This review addresses the progress in research on the use of hyperbaric oxygen therapy combined with radiotherapy. For brain metastases, the combination of hyperbaric oxygen therapy and stereotactic radiosurgery is both feasible and advantagenous. This combination not only offers protection against radiation-induced brain injury but also supports the recovery of neurological and motor functions. The incidence of adverse reactions to hyperbaric oxygen therapy is relatively low, and it is safe and manageable. Future efforts should be made to investigate the mechanisms by which hyperbaric oxygen therapy combined with radiotherapy treats gliomas and brain metastases, optimize protection of the combined treatment against brain injury, minimizing adverse reactions, conducting multidisciplinary research and clinical trials, and training healthcare providers to facilitate broader clinical application.

Engineering exosome membrane disguised thermal responsive system for targeted drug delivery and controlled release across the blood-brain barrier

The blood-brain barrier (BBB) presents a significant challenge for the delivery of chemotherapy drugs to brain tumors, leading to ineffective drug concentrations at the tumor site and contributing to chemotherapy resistance. The hypoxic tumor microenvironment further complicates this process, ultimately resulting in poor patient prognosis. In this study, we developed a thermoresponsive nanocarrier system that incorporates (Ru)(Pt) bimetallic nanoparticles onto defective TiOx nanoparticles with abundant oxygen vacancies, generating composite Ru/Pt-TiOx nanoparticles with photothermal and photocatalytic properties. The Ru and Pt in the nanoparticles enhance the metal-carrier interactions, with Ru increasing both light absorption and photothermal conversion efficiency and Pt catalyzing the conversion of endogenous H2O2 in tumors to produce oxygen. The oxygen produced within the tumor microenvironment reduces HIF-1α, MDR1 and P-gp expression, thereby inhibiting efflux and allowing doxorubicin to accumulate inside the cells. DOX was incorporated into a phase change material and combined with multiple Ru/Pt-TiOx nanoparticles to form composite RPTiOx-DOX particles that can control the release of DOX under near-infrared irradiation. In an effort to overcome the blocking effect of the BBB, we wrapped the RPTiOx-DOX nanoparticles with Angiopep-2-functionalized macrophage exosome membranes. Furthermore, the changes in the internal environment promote macrophage phenotypic transformation (M2→M1) to some extent and further inhibit tumor growth via immunoregulation. In this work, a novel drug delivery system capable of traversing the BBB and exerting synergistic antitumor effects through photostimulated therapeutic agents is described, providing innovative insights for the development of stimulus-responsive composite nanoparticle drug formulations.

Jaw Osteomyelitis

Mandibular osteomyelitis is caused most commonly by members of the oral flora in the setting of dental infection or dental manipulation, often in patients with underlying mandible pathology. Recognizing and treating mandible infections is especially challenging when they are associated with osteonecrotic conditions that are themselves difficult to manage and that may be associated with symptoms and testing results that mimic infection. Optimized diagnosis and management of mandible infections require collaboration between specialists in surgical and medical aspects of care, with the goal of clearing or controlling infection while maximizing function.

A pH-Sensitive Nanosized Covalent-Organic Polymer for Enhanced Tumor Photodynamic Immunotherapy by Hypoxia Relief and STAT3 Inhibition

Photodynamic therapy (PDT) is a promising cancer therapy modality by generating reactive oxygen species (ROS) and triggering immunogenic cell death. However, the therapeutic effect of PDT is strongly limited by tumor hypoxia and immunosuppressive landscape. Herein, a pH-sensitive nanosized covalent-organic polymer (COP), composed of the photosensitizer porphyrin and pyruvate kinase inhibitor vitamin K3 (VK3), is designed to overcome these issues. The signal transducer and activator of transcription 3 (STAT3) inhibitor WP1066 is further encapsulated into COPs to form a WP1066-loaded COP (TVW). As an inhibitor of pyruvate kinase, VK3 can reduce intracellular oxygen consumption by inhibiting the glycolytic pathway, leading to the alleviation of the tumor hypoxic microenvironment. The relief of tumor hypoxia by VK3 enhances photodynamic cytotoxicity by generating more ROS. Meanwhile, STAT3 acts as a major regulator of PD-L1, a key inhibitor that promotes immune escape. WP1066 effectively inhibits the expression of STAT3 and reduces PD-L1 expression, thereby significantly inhibiting tumor immune escape and enhancing antitumor efficacy in a synergistic manner. The antitumor capacity of photodynamic immunotherapy is extensively investigated in a murine subcutaneous hepatocellular carcinoma model. This photo-immunotherapy may provide an effective combination regimen for the efficient treatment of solid tumors such as hepatocellular carcinoma.

Hyperbaric Oxygen Regulates Tumor pH to Boost Copper‐Doped Hydroxyethyl Starch Conjugate Nanoparticles Against Cancer Stem Cells

An extracellular acidic environment and an intracellular mildly alkaline environment induced by carbonic anhydrase 9 (CA9) play a critical role in self‐renewal, invasion, migration, and drug resistance of cancer stem cells (CSCs) within hypoxic solid tumors. Here, we report an antitumor strategy leveraging hyperbaric oxygen therapy (HBO) to regulate tumor pH and boost hydroxyethyl starch‐doxorubicin‐copper nanoparticles (HHD‐Cu NPs) against CSCs. HBO overcomes tumor hypoxia, downregulates pH‐regulatory proteins such as CA9, and leads to intracellular accumulation of acidic metabolites. As a result, HBO promotes intracellular acidification of both tumor cells and CSCs, triggering efficient doxorubicin release and the potent copper‐mediated chemical dynamic effect of subsequently administered dual‐acid‐responsive HHD‐Cu NPs. The combination of HBO with HHD‐Cu NPs not only eliminates tumor cells but also inhibits CSCs, altogether leading to potent tumor inhibition. This study explores a new function of clinical‐widely used HBO and establishes a novel combination therapy for treating CSCs abundant hypoxic solid tumors.

The solid tumor microenvironment and related targeting strategies: a concise review

The malignant tumor is a serious disease threatening human life. Increasing studies have confirmed that the tumor microenvironment (TME) is composed of a variety of complex components that precisely regulate the interaction of tumor cells with other components, allowing tumor cells to continue to proliferate, resist apoptosis, evade immune surveillance and clearance, and metastasis. However, the characteristics of each component and their interrelationships remain to be deeply understood. To target TME, it is necessary to deeply understand the role of various components of TME in tumor growth and search for potential therapeutic targets. Herein, we innovatively classify the TME into physical microenvironment (such as oxygen, pH, etc.), mechanical microenvironment (such as extracellular matrix, blood vessels, etc.), metabolic microenvironment (such as glucose, lipids, etc.), inflammatory microenvironment and immune microenvironment. We introduce a concise but comprehensive classification of the TME; depict the characteristics of each component in TME; summarize the existing methods for detecting each component in TME; highlight the current strategies and potential therapeutic targets for TME; discuss current challenges in presenting TME and its clinical applications; and provide our prospect on the future research direction and clinical benefits of TME.

Hyperbaric Oxygen Therapy for Managing Cancer Treatment Complications: A Safety Evaluation

Background and Objectives: Hyperbaric oxygen therapy (HBOT) has shown promise in managing complications due to cancer treatments, particularly those related to radiotherapy and surgery. Despite its clinical benefits, concerns persist regarding its potential to influence cancer progression. This study aimed to evaluate the safety and clinical outcomes of HBOT in patients with active or previously treated solid tumors. Methods: A retrospective analysis was conducted on patients with solid tumors who underwent at least five HBOT sessions. Comprehensive data, including patient demographics, cancer type, total number of HBOT sessions, imaging findings, and clinical outcomes (recurrence, metastasis, and mortality), were collected. Descriptive statistics and the relationship between the number of HBOT sessions and long-term cancer outcomes were analyzed. Results: This study included 45 patients (median age: 64 years; 60% male) who received a median of 27 HBOT sessions. At initiation, 27.9% of the patients were classified as cured, 53.5% were in remission, and 18.6% had active cancer. Over a median follow-up period of 783 days, 8.7% experienced recurrence, 2.7% had persistent active cancer, and 59.5% had no recurrence. No HBOT-related complications were observed during the course of HBOT. Statistical analyses revealed no significant correlations between the number of HBOT sessions and metastasis (p = 0.213) or mortality (p = 0.881). Conclusions: HBOT appears to be a safe and effective adjunctive therapy for managing complications in patients with solid tumors. No evidence was found to suggest HBOT contributes to tumor progression, recurrence, or metastasis. Future prospective studies with larger cohorts are needed to confirm these results and further evaluate the therapeutic role of HBOT in oncology.

Hypoxia as a critical player in extracellular vesicles-mediated intercellular communication between tumor cells and their surrounding microenvironment

In the past years, increasing attention has been paid to the role of extracellular vesicles (EVs) as mediators of intercellular communication in cancer. These small size particles mediate the intercellular transfer of important bioactive molecules involved in malignant initiation and progression. Hypoxia, or low partial pressure of oxygen, is recognized as a remarkable feature of solid tumors and has been demonstrated to exert a profound impact on tumor prognosis and therapeutic efficacy. Indeed, the high-pitched growth rate and chaotic neovascular architecture that embodies solid tumors results in a profound reduction in oxygen pressure within the tumor microenvironment (TME). In response to oxygen-deprived conditions, tumor cells and their surrounding milieu develop homeostatic adaptation mechanisms that contribute to the establishment of a pro-tumoral phenotype. Latest evidence suggests that the hypoxic microenvironment that surrounds the tumor bulk may be a clincher for the observed elevated levels of circulating EVs in cancer patients. Thus, it is proposed that EVs may play a role in mediating intercellular communication in response to hypoxic conditions. This review focuses on the EVs-mediated crosstalk that is established between tumor cells and their surrounding immune, endothelial, and stromal cell populations, within the hypoxic TME.

Melatonin for gastric cancer treatment: where do we stand?

Gastric cancer (GC) is the third leading reason of death in men and the fourth in women. Studies have documented an inhibitory function of melatonin on the proliferation, progression and invasion of GC cells. MicroRNAs (miRNAs) are small, non-coding RNAs that play an important function in regulation of biological processes and gene expression of the cells. Some studies reported that melatonin can suppress the progression of GC by regulating the exosomal miRNAs. Thus, melatonin represents a promising potential therapeutic agent for subjects with GC. Herein, we evaluate the existing data of both in vivo and in vitro studies to clarify the molecular processes involved in the therapeutic effects of melatonin in GC. The data emphasize the critical function of melatonin in several signaling ways by which it may inhibit cancer cell proliferation, decrease chemo-resistance, induce apoptosis as well as limit invasion, angiogenesis, and metastasis. This review provides a resource that identifies some of the mechanisms by which melatonin controls GC enlargement. In light of the findings, melatonin should be considered a novel and testable therapeutic mediator for GC treatment.

Internal Malignancy Risk After Carbon Monoxide Poisoning: A Nationwide Population-Based Cohort Study

Background: We aimed to investigate the association between acute carbon monoxide (CO) poisoning and the risk of internal malignancies, including hematologic malignancies. Methods: The study population was derived from the National Health Insurance Service (NHIS) database of Korea between 2002 and 2022. Adults diagnosed with CO poisoning and controls were included. Demographics, socioeconomic statuses, lifestyle factors, and comorbidity profiles of participants were retrieved from the NHIS database. Covariates potentially associated with disease outcomes were selected based on the available literature and biological plausibility, balanced between the two cohorts using inverse probability of treatment weighting, and applied to adjust multivariable models. Results: Overall, 42,874 patients with CO poisoning and 905,285 controls were included; both cohorts comprised 44.3% females. The mean age of the CO poisoning and controls was 51.5 and 50.9 years, respectively. Patients with CO poisoning had a 1.02-fold increase in the overall risk of malignancy (a 1.03-fold increase in solid organ malignancies and a 0.71-fold decrease in hematologic malignancies) compared with controls. The risk of internal malignancy was increased in the oral cavity (adjusted hazard ratio, 1.33; 95% confidence intervals, 1.19-1.49), lungs (1.39; 1.33-1.46), bone (1.68; 1.23-2.30), cervix (1.32; 95% CI, 1.17-1.49), and kidneys (1.14; 1.04-1.24). Conversely, the risk of internal malignancies was decreased in the thorax (0.59; 0.45-0.77), anus (0.14; 0.06-0.34), uterus (0.71; 0.60-0.82), ovaries (0.59; 0.45-0.77), prostate (0.89; 0.84-0.95), Hodgkin lymphoma (0.35; 0.20-0.61), non-Hodgkin lymphoma (0.67; 0.59-0.75), and multiple myeloma (0.36; 0.30-0.43). Conclusions: CO poisoning was associated with the development of internal malignancies.

ROS-mediated Therapeutics Combined with Metal-based Porphyrin Nanoparticles and their Applications in Tumor Treatment

High concentrations of reactive oxygen species (ROS) can disrupt cell structure and induce apoptosis and necrosis of tumor cells. Photodynamic therapy (PDT) and chemodynamic therapy (CDT) are two cancer treatments mediated by reactive oxygen species. Oxygen molecules (O2) are one of the indispensable factors in PDT and hypoxic tumor sites limit its application. However, another ROS-mediated method, CDT, can generate •OH and O2in situ by Fenton reaction or Fenton-like reaction. Synergistic PDT/CDT therapy is a strategy to overcome the limitations of tumor microenvironment therapy. In this review, PDT and CDT therapies are briefly introduced, with an emphasis on metal-basrd porphyrin nanoparticles constructed in different ways for PDT/CDT dual-mode therapy. By introducing the history and latest design schemes of the treatment model, it provides ideas for researchers engaged in ROS-mediated cancer therapies.

Hyperbaric oxygen therapy outcomes in post-irradiated patient undergoing microvascular breast reconstruction: A preliminary retrospective comparative study

Introduction

Radiotherapy is a challenge in autologous breast reconstruction because of its impact on cutaneous and vascular systems. Hyperbaric oxygen therapy (HBOT) is a recognized treatment of radiation-related complications. We aimed to assess the impact of perioperative HBOT on irradiated breast microvascular reconstructive outcomes.

Method

We reviewed the medical charts of patients who received radiotherapy and then underwent secondary free autologous breast reconstruction at our institution. Data on demographics, HBOT protocol, intervention characteristics and post-operative complications were collected. Outcomes of the irradiated patients were then compared between the HBOT and non-HBOT groups.

Results

Fourteen patients were included (11 unilateral and 2 bilateral deep inferior epigastric artery perforator flaps and 1 free transverse rectus abdominis muscle flap). Seven patients received HBOT and 7 did not. In the non-HBOT group, there were 1 Clavien-Dindo grade II, 1 Clavien-Dindo grade IIIa and 2 Clavien-Dindo grade IIIb post-operative complications. In the HBOT group, there were 3 Clavien-Dindo grade I, 1 Clavien-Dindo grade IIIa and 2 Clavien-Dindo grade IIIb post-operative complications. The mean operative time was 452.3 minutes (SD ±62.4 minutes) for unilateral cases without HBOT and 457.8 minutes (SD ±102.1 minutes) with HBOT (p=0.913). Mean ischaemia time per flap without HBOT was 109.4 minutes (SD ±51.8 minutes) versus 80.1 minutes (SD ±37.7 minutes) in the HBOT group (p=0.249).

Conclusion

This study provides insights into the potential of HBOT treatment in preparing patients with irradiated breast cancer for secondary autologous reconstruction.

The oxygen puzzle in FLASH radiotherapy: A comprehensive review and experimental outlook

FLASH radiotherapy is attracting increasing interest because it maintains tumor control while inflicting less damage to normal tissues compared to conventional radiotherapy. This sparing effect, the so-called FLASH effect, is achieved when radiation is delivered at ultra-high dose rates (≥40 Gy/s). Although the FLASH effect has already been demonstrated in several preclinical models, a complete mechanistic description explaining why tumors and normal tissues respond differently is still missing. None of the current hypotheses fully explains the experimental evidence. A common point between many of these is the role of oxygen, which is described as a major factor, either through transient hypoxia in the form of dissolved molecules, or reactive oxygen species (ROS). Therefore, this review focuses on both forms of this molecule, retracing old and more recent theories, while proposing new mechanisms that could provide a complete description of the FLASH effect based on preclinical and experimental evidence. In addition, this manuscript describes a set of experiments designed to provide the FLASH community with new tools for exploring the post-irradiation fate of ROS and their potential biological implications.

Increased oxygen stimulation promotes chemoresistance and phenotype shifting through PLCB1 in gliomas

Gliomas, the most common CNS (central nerve system) tumors, face poor survival due to severe chemoresistance exacerbated by hypoxia. However, studies on whether altered hypoxic conditions benefit for chemo-sensitivity and how gliomas react to increased oxygen stimulation are limited. In this study, we demonstrated that increased oxygen stimulation promotes glioma growth and chemoresistance. Mechanically, increased oxygen stimulation upregulates miR-1290 levels. miR-1290, in turn, downregulates PLCB1, while PLCB1 facilitates the proteasomal degradation of β-catenin and active-β-catenin by increasing the proportion of ubiquitinated β-catenin in a destruction complex-independent mechanism. This process inhibits PLCB1 expression, leads to the accumulation of active-β-catenin, boosting Wnt signaling through an independent mechanism and ultimately promoting chemoresistance in glioma cells. Pharmacological inhibition of Wnt by WNT974 could partially inhibit glioma volume growth and prolong the shortened survival caused by increased oxygen stimulation in a glioma-bearing mouse model. Moreover, PLCB1, a key molecule regulated by increased oxygen stimulation, shows promising predictive power in survival analysis and has great potential to be a biomarker for grading and prognosis in glioma patients. These results provide preliminary insights into clinical scenarios associated with altered hypoxic conditions in gliomas, and introduce a novel perspective on the role of the hypoxic microenvironment in glioma progression. Furthermore, the outcomes reveal the potential risks of utilizing hyperbaric oxygen treatment (HBOT) in glioma patients, particularly when considering HBOT as a standalone option to ameliorate neuro-dysfunctions or when combining HBOT with a single chemotherapy agent without radiotherapy.

Hyperbaric oxygen therapy increases the effect of 5-fluorouracil chemotherapy on experimental colorectal cancer in mice

Tumor hypoxia may compromise the results of chemotherapy for treating colorectal cancer because it stimulates angiogenesis and the release of tumor growth factors. Hyperbaric oxygen (HBO) supplementation may potentiate the effects of chemotherapy in such cases. This study aimed to assess the effect of HBO therapy combined with chemotherapy on the treatment of colorectal cancer in mice. C57BL6 mice were submitted to the intrarectal instillation of N-methyl-N-nitrosoguanidine (MNNG) and treated with 5-fluorouracil (5FU) and/or HBO therapy. The MNNG group presented the highest dysplastic crypt rate. The 5FU + HBO group presented the highest rate of apoptotic cells per dysplastic crypt. The 5FU group presented the highest expression of hypoxia-inducible factor-1 alpha and CD44. HBO therapy increased the effect of 5FU on the treatment of the experimental colorectal neoplasia in mice.

A Self-Catalytic NO/O2 Gas-Releasing Nanozyme for Radiotherapy Sensitization through Vascular Normalization and Hypoxia Relief

Radiotherapy (RT), essential for treating various cancers, faces challenges from tumor hypoxia, which induces radioresistance. A tumor-targeted "prosthetic-Arginine" coassembled nanozyme system, engineered to catalytically generate nitric oxide (NO) and oxygen (O2) in the tumor microenvironment (TME), overcoming hypoxia and enhancing radiosensitivity is presented. This system integrates the prosthetic heme of nitric oxide synthase (NOS) and catalase (CAT) with NO-donating Fmoc-protected Arginine and Ru3+ ions, creating HRRu nanozymes that merge NOS and CAT functionalities. Surface modification with human heavy chain ferritin (HFn) improves the targeting ability of nanozymes (HRRu-HFn) to tumor tissues. In the TME, strategic arginine incorporation within the nanozyme allows autonomous O2 and NO release, triggered by endogenous hydrogen peroxide, elevating NO and O2 levels to normalize vasculature and improve blood perfusion, thus mitigating hypoxia. Employing the intrinsic O2-transporting ability of heme, HRRu-HFn nanozymes also deliver O2 directly to the tumor site. Utilizing esophageal squamous cell carcinoma as a tumor model, the studies reveal that the synergistic functions of NO and O2 production, alongside targeted delivery, enable the HRRu-HFn nanozymes to combat tumor hypoxia and potentiate radiotherapy. This HRRu-HFn nanozyme based approach holds the potential to reduce the radiation dose required and minimize side effects associated with conventional radiotherapy.

A Self‐Catalytic NO/O2 Gas‐Releasing Nanozyme for Radiotherapy Sensitization through Vascular Normalization and Hypoxia Relief

Radiotherapy (RT), essential for treating various cancers, faces challenges from tumor hypoxia, which induces radioresistance. A tumor‐targeted “prosthetic‐Arginine” coassembled nanozyme system, engineered to catalytically generate nitric oxide (NO) and oxygen (O2) in the tumor microenvironment (TME), overcoming hypoxia and enhancing radiosensitivity is presented. This system integrates the prosthetic heme of nitric oxide synthase (NOS) and catalase (CAT) with NO‐donating Fmoc‐protected Arginine and Ru3+ ions, creating HRRu nanozymes that merge NOS and CAT functionalities. Surface modification with human heavy chain ferritin (HFn) improves the targeting ability of nanozymes (HRRu‐HFn) to tumor tissues. In the TME, strategic arginine incorporation within the nanozyme allows autonomous O2 and NO release, triggered by endogenous hydrogen peroxide, elevating NO and O2 levels to normalize vasculature and improve blood perfusion, thus mitigating hypoxia. Employing the intrinsic O2‐transporting ability of heme, HRRu‐HFn nanozymes also deliver O2 directly to the tumor site. Utilizing esophageal squamous cell carcinoma as a tumor model, the studies reveal that the synergistic functions of NO and O2 production, alongside targeted delivery, enable the HRRu‐HFn nanozymes to combat tumor hypoxia and potentiate radiotherapy. This HRRu‐HFn nanozyme based approach holds the potential to reduce the radiation dose required and minimize side effects associated with conventional radiotherapy.

Reactive Oxygen Species (ROS)-Mediated Antibacterial Oxidative Therapies: Available Methods to Generate ROS and a Novel Option Proposal

The increasing emergence of multidrug-resistant (MDR) pathogens causes difficult-to-treat infections with long-term hospitalizations and a high incidence of death, thus representing a global public health problem. To manage MDR bacteria bugs, new antimicrobial strategies are necessary, and their introduction in practice is a daily challenge for scientists in the field. An extensively studied approach to treating MDR infections consists of inducing high levels of reactive oxygen species (ROS) by several methods. Although further clinical investigations are mandatory on the possible toxic effects of ROS on mammalian cells, clinical evaluations are extremely promising, and their topical use to treat infected wounds and ulcers, also in presence of biofilm, is already clinically approved. Biochar (BC) is a carbonaceous material obtained by pyrolysis of different vegetable and animal biomass feedstocks at 200-1000 °C in the limited presence of O2. Recently, it has been demonstrated that BC's capability of removing organic and inorganic xenobiotics is mainly due to the presence of persistent free radicals (PFRs), which can activate oxygen, H2O2, or persulfate in the presence or absence of transition metals by electron transfer, thus generating ROS, which in turn degrade pollutants by advanced oxidation processes (AOPs). In this context, the antibacterial effects of BC-containing PFRs have been demonstrated by some authors against Escherichia coli and Staphylococcus aureus, thus giving birth to our idea of the possible use of BC-derived PFRs as a novel method capable of inducing ROS generation for antimicrobial oxidative therapy. Here, the general aspects concerning ROS physiological and pathological production and regulation and the mechanism by which they could exert antimicrobial effects have been reviewed. The methods currently adopted to induce ROS production for antimicrobial oxidative therapy have been discussed. Finally, for the first time, BC-related PFRs have been proposed as a new source of ROS for antimicrobial therapy via AOPs.

Hyperbaric oxygen enhances tumor penetration and accumulation of engineered bacteria for synergistic photothermal immunotherapy

Bacteria-mediated cancer therapeutic strategies have attracted increasing interest due to their intrinsic tumor tropism. However, bacteria-based drugs face several challenges including the large size of bacteria and dense extracellular matrix, limiting their intratumoral delivery efficiency. In this study, we find that hyperbaric oxygen (HBO), a noninvasive therapeutic method, can effectively deplete the dense extracellular matrix and thus enhance the bacterial accumulation within tumors. Inspired by this finding, we modify Escherichia coli Nissle 1917 (EcN) with cypate molecules to yield EcN-cypate for photothermal therapy, which can subsequently induce immunogenic cell death (ICD). Importantly, HBO treatment significantly increases the intratumoral accumulation of EcN-cypate and facilitates the intratumoral infiltration of immune cells to realize desirable tumor eradication through photothermal therapy and ICD-induced immunotherapy. Our work provides a facile and noninvasive strategy to enhance the intratumoral delivery efficiency of natural/engineered bacteria, and may promote the clinical translation of bacteria-mediated synergistic cancer therapy.

Hyperbaric Oxygen Therapy as an Alternative Therapeutic Option for Radiation-Induced Necrosis Following Radiotherapy for Intracranial Pathologies

BACKGROUND

Radiotherapy (RT) is a feasible adjuvant therapeutic option for managing intracranial pathologies. One of the late complications of RT that frequently develops within months following RT is radiation necrosis (RN). Corticosteroids are the first-line therapeutic option for RNs; however, in case of unfavorable outcomes or intolerability, several other options, including bevacizumab, laser interstitial thermal therapy, surgery, and hyperbaric oxygen therapy (HBOT). Our goal was to investigate the feasibility and efficacy of the application of HBOT in RNs following RT and help physicians make decisions based on the latest data in the literature.

METHODS

We provide a comprehensive review of the literature on the current issues of utilization of HBOT in RNs.

RESULTS

We included 11 studies with a total of 46 patients who underwent HBOT. Most of the cases were diagnosed with brain tumors or arteriovenous malformations. Improvement was achieved in most of the cases.

DISCUSSION

HBOT is a noninvasive therapeutic intervention that can play a role in adjuvant therapy concurrent with RT and chemotherapy and treating RNs. HBOT resolves the RN through 3 mechanisms, including angiogenesis, anti-inflammatory modulation, and cellular repair. Previous studies demonstrated that HBOT is a feasible and well-tolerated therapeutic option that has shown promising results in improving clinical and radiological outcomes in intracranial RNs. Complications of HBOT are usually mild and reversible.

CONCLUSIONS

HBOT is a feasible and effective therapeutic option in steroid-refractory RNs and is associated with favorable outcomes and a low rate of side effects.

Oxygen Imaging of a Rabbit Tumor Using a Human-Sized Pulse Electron Paramagnetic Resonance Imager

PURPOSE

Spatial heterogeneity in tumor hypoxia is one of the most important factors regulating tumor growth, development, aggressiveness, metastasis, and affecting treatment outcome. Most solid tumors are known to have hypoxia or low oxygen levels (pO2 ≤10 torr). Electron paramagnetic resonance oxygen imaging (EPROI) is an emerging oxygen mapping technology. EPROI utilizes the linear relationship between the relaxation rates of the injectable OX071 trityl spin probe and the partial oxygen pressure (pO2). However, most of the EPROI studies have been limited to mouse models of solid tumors because of the instrument-size limitations. The purpose of this work was to develop a human-sized 9-mT (250 MHz resonance frequency, 60 cm bore size) pulse EPROI instrument and evaluate its performance with rabbit VX-2 tumor oxygen imaging.

METHODS

A New Zealand white rabbit with a 3.2-cm VX-2 tumor in the calf muscle was imaged using the human-sized EPROI instrument and a 2.25-in. ID volume coil. The animal received a ~8-min intravenous injection of OX071 (5.2 mL total volume at 72 mM concentration) and, after 75 min, an intratumoral injection (120 μL total at 5 mM OX071 concentration) and underwent EPROI. At the end of the experiments, MRI was performed using a preclinical 9.4-T MRI system to outline the tumor boundaries.

RESULTS

For the first time, a human-sized pulse EPROI instrument with a 60-cm bore size/250-MHz frequency was built and evaluated using rabbit tumor oxygen imaging. For the first time, the systemic IV injection of the oxygen-sensitive trityl OX071 spin probe was used for an animal of this size. The resulting EPROI image from the IV injection showed complete tumor coverage. The image obtained after intratumoral injection showed localized coverage in the upper lobe of the tumor, demonstrating the need for improved intratumoral injection protocol.

CONCLUSIONS

This study demonstrates the performance of the world's first human-sized pulse EPROI instrument. It also demonstrates that the EPROI of larger animals can be performed using the systemic injection of a manageable amount of the spin probe. This brings EPROI one step closer to clinical applications in cancer therapies. Oxygen imaging is a platform technology, and the instrument and techniques developed here will also be useful for other clinical applications.

HBO regulates the Warburg effect of hypoxic HCC cells through miR-103a-3p/TRIM35

BACKGROUND

There are a lot of studies on the treatment of tumors with hyperbaric oxygen, while most of them are in breast cancer, prostate cancer and so on. However, there are still few studies on hyperbaric oxygen in treating hepatocellular carcinoma (HCC). According to the current data, hyperbaric oxygen is an effective means to intervene in tumors. The Warburg effect is a unique marker of glucose metabolism in tumors related to hypoxia, making it possible for hyperbaric oxygen to interfere with the tumor through the Warburg effect.

METHOD

We used the hypoxia/hyperbaric oxygen(HBO)-exposed HCC cells for in vitro studies. Glucose uptake, lactic acid, and adenosine triphosphate (ATP) assessed the Warburg effect. The expression of miR-103a-3p in HCC was detected by using qRT-PCR. The effect of miR-103a-3p/TRIM35 expression level on the cells was measured using the CCK8 method and flow cytometry. The molecular biological mechanism of miR-103a-3p in HCC was examined using the luciferase reporter, MS2-RIP assays.

RESULT

HBO inhibited the Warburg effect in hypoxic HCC cells. HBO suppressed the expression of miR-103a-3p in hypoxic HCC cells, and miR-103a-3p inhibited the expression of TRIM35 in hypoxic HCC cells. With HBO exposure, miR-103a-3p/TRIM35 regulated the Warburg effect of hypoxic HCC cells.

CONCLUSION

These findings reveal that HBO regulates the Warburg effect of hypoxic HCC cells through miR-103a-3p/TRIM35 and inhibits tumor growth.

Mitochondrial-Stem Cell Connection: Providing Additional Explanations for Understanding Cancer

The cancer paradigm is generally based on the somatic mutation model, asserting that cancer is a disease of genetic origin. The mitochondrial-stem cell connection (MSCC) proposes that tumorigenesis may result from an alteration of the mitochondria, specifically a chronic oxidative phosphorylation (OxPhos) insufficiency in stem cells, which forms cancer stem cells (CSCs) and leads to malignancy. Reviewed evidence suggests that the MSCC could provide a comprehensive understanding of all the different stages of cancer. The metabolism of cancer cells is altered (OxPhos insufficiency) and must be compensated by using the glycolysis and the glutaminolysis pathways, which are essential to their growth. The altered mitochondria regulate the tumor microenvironment, which is also necessary for cancer evolution. Therefore, the MSCC could help improve our understanding of tumorigenesis, metastases, the efficiency of standard treatments, and relapses.

Ultrasound-augmented cancer immunotherapy

Cancer is a growing worldwide health problem with the most broadly studied treatments, in which immunotherapy has made notable advancements in recent years. However, innumerable patients have presented a poor response to immunotherapy and simultaneously experienced immune-related adverse events, with failed therapeutic results and increased mortality rates. Consequently, it is crucial to develop alternate tactics to boost therapeutic effects without producing negative side effects. Ultrasound is considered to possess significant therapeutic potential in the antitumor field because of its inherent characteristics, including cavitation, pyrolysis, and sonoporation. Herein, this timely review presents the comprehensive and systematic research progress of ultrasound-enhanced cancer immunotherapy, focusing on the various ultrasound-related mechanisms and strategies. Moreover, this review summarizes the design and application of current sonosensitizers based on sonodynamic therapy, with an attempt to provide guidance on new directions for future cancer therapy.

The clinical manifestations and molecular pathogenesis of radiation fibrosis

Advances in radiation techniques have enabled the precise delivery of higher doses of radiotherapy to tumours, while sparing surrounding healthy tissues. Consequently, the incidence of radiation toxicities has declined, and will likely continue to improve as radiotherapy further evolves. Nonetheless, ionizing radiation elicits tissue-specific toxicities that gradually develop into radiation-induced fibrosis, a common long-term side-effect of radiotherapy. Radiation fibrosis is characterized by an aberrant wound repair process, which promotes the deposition of extensive scar tissue, clinically manifesting as a loss of elasticity, tissue thickening, and organ-specific functional consequences. In addition to improving the existing technologies and guidelines directing the administration of radiotherapy, understanding the pathogenesis underlying radiation fibrosis is essential for the success of cancer treatments. This review integrates the principles for radiotherapy dosimetry to minimize off-target effects, the tissue-specific clinical manifestations, the key cellular and molecular drivers of radiation fibrosis, and emerging therapeutic opportunities for both prevention and treatment.

Cancer-Thylakoid Hybrid Membrane Camouflaged Thulium Oxide Nanoparticles with Oxygen Self-Supply Capability for Tumor-Homing Phototherapy

Nanomaterials that generate reactive oxygen species (ROS) upon light irradiation have significant applications in various fields, including photodynamic therapy (PDT) that is widely recognized as a highly momentous strategy for the eradication of cancer cells. However, the ROS production rate of photosensitizers, as well as the tumor hypoxia environment, are two major challenges that restrict the widespread application of PDT. In this study, a cancer-thylakoid hybrid membrane-camouflaged thulium oxide nanoparticles (Tm2O3) for tumor-homing phototherapy through dual-stage-light-guided ROS generation and oxygen self-supply is developed. Tm2O3 as a type II photosensitizer are viable for NIR-stimulated ROS generation due to the unique energy levels, large absorption cross section, and long lifetime of the 3H4 state of Tm ions. The thylakoid membrane (TK) plays a catalase-like role in converting hydrogen peroxide into oxygen and also acts as a natural photosensitizer that can generate lethal ROS through electron transfer when exposed to light. In addition, fluorescence dye DiR is embedded in the hybrid membrane for in vivo tracing as well as photothermal therapy. Results show that tumors in Tm2O3@TK-M/DiR group are effectively ablated following dual-stage-light irradiation, highlighting the promising potential of rare-earth element-based type II photosensitizers in various applications.

Hyperbaric oxygen enhances X-ray induced ferroptosis in oral squamous cell carcinoma cells

OBJECTIVE

The objective of this study was to investigate the combined effect of X-ray radiation (IR) and hyperbaric oxygen (HBO) on oral squamous cell carcinoma (OSCC) cells and to explore the possible molecular mechanism.

METHODS

The OSCC cells were treated with or without IR, together with or without HBO co-exposure. Cells were transfected with specific plasmids using Lipofectamine 2000. The cell varieties, apoptosis markers, and ferroptosis markers were determined by using appropriate method. OSCC xenograft mice model was categorized into several subgroups according to the specific treatement. GPX4 expressions were determined by immunohistochemistry (IHC) in OSCC tissues and were tested by ELISA in serums from OSCC patients.

RESULTS

The co-exposure of IR and HBO significantly strengthened the cytotoxicity of IR on SCC15-S cells in ferroptosis-dependent manner. The regulated GPX4/ferroptosis mediated the HBO function on re-sensitizing the radio-resistant OSCC cells to IR. In xenograft mice, co-exposure of IR and HBO can significantly reduce the tumor under IR activation compared with IR alone. Clinical data indicated that high GPX4 levels were associated with poor chemo-radiotherapy outcome.

CONCLUSIONS

HBO could re-sensitize radio-resistant OSCC cells through GPX4/ferroptosis regulation. These results provide a potential therapeutic strategy for clinical radio-resistance.

Biomaterial-Based Responsive Nanomedicines for Targeting Solid Tumor Microenvironments

Solid tumors are composed of a highly complex and heterogenic microenvironment, with increasing metabolic status. This environment plays a crucial role in the clinical therapeutic outcome of conventional treatments and innovative antitumor nanomedicines. Scientists have devoted great efforts to conquering the challenges of the tumor microenvironment (TME), in respect of effective drug accumulation and activity at the tumor site. The main focus is to overcome the obstacles of abnormal vasculature, dense stroma, extracellular matrix, hypoxia, and pH gradient acidosis. In this endeavor, nanomedicines that are targeting distinct features of TME have flourished; these aim to increase site specificity and achieve deep tumor penetration. Recently, research efforts have focused on the immune reprograming of TME in order to promote suppression of cancer stem cells and prevention of metastasis. Thereby, several nanomedicine therapeutics which have shown promise in preclinical studies have entered clinical trials or are already in clinical practice. Various novel strategies were employed in preclinical studies and clinical trials. Among them, nanomedicines based on biomaterials show great promise in improving the therapeutic efficacy, reducing side effects, and promoting synergistic activity for TME responsive targeting. In this review, we focused on the targeting mechanisms of nanomedicines in response to the microenvironment of solid tumors. We describe responsive nanomedicines which take advantage of biomaterials' properties to exploit the features of TME or overcome the obstacles posed by TME. The development of such systems has significantly advanced the application of biomaterials in combinational therapies and in immunotherapies for improved anticancer effectiveness.

Development of Anticancer Ferric Complex Based on Human Serum Albumin Nanoparticles That Generate Oxygen in Cells to Overcome Hypoxia-Induced Resistance in Metal Chemotherapy

To achieve the remarkable therapeutic efficacy of a ferric (Fe) complex via a reactive oxygen species (ROS) mechanism in solid tumors, a therapeutic Fe-based Schiff-base complex (Fe1) was synthesized and encapsulated in human serum albumin (HSA) nanoparticles (NPs), which generated oxygen (O2) in cancer cells in situ. The HSA-Fe1-O2 NP (HSA-Fe1-O2NP) delivery system effectively overcame hypoxia-induced resistance in metal chemotherapy, alleviated the hypoxic condition of tumor tissues, and showed excellent tumor suppression by generating excess ROS and promoting the apoptosis of SK-N-MC tumor cells. The HSA-Fe1-O2NPs not only enhanced the ability of the Fe1 complex to target tumor cells but also decreased adverse effects in vivo.

Selected possibilities of physical medicine versus cancer diseases

OBJECTIVE

Aims: This review aims to synthesize the latest literature on physical treatments for wounds, focusing on the use of ozone therapy, topical oxygen therapy, pulsed electromagnetic field therapy, and red light therapy in oncology patients. It evaluates the indications, benefits, and contraindications of these therapies, especially concerning cancer..

PATIENTS AND METHODS

Materials and Methods: A literature search was conducted in publicly available online databases, covering publications in English and Polish from 2010 to 2024. The inclusion criteria comprised clinical trials, systematic reviews, meta-analyses, and review articles on physical treatments for wounds in oncology patients. The selection process involved pre-selection, title and abstract review, and full-text review to ensure compliance with the inclusion criteria. Data were analyzed to identify mechanisms of action, therapeutic efficacy, and potential risks associated with these therapies in oncology patients. Ozone therapy showed potential in reducing bacterial load and tumor hypoxia, enhancing chemotherapy efficacy. Topical oxygen therapy was effective for chronic wounds, with careful application near tumor sites. Pulsed electromagnetic field therapy demonstrated promising anticancer effects, inducing apoptosis in cancer cells. Red light therapy, while beneficial for managing side effects of cancer treatments, was contraindicated in areas with active tumors due to the risk of stimulating cancer cell proliferation.

CONCLUSION

Conclusions: Physical therapies offer benefits in wound management but require careful consideration in oncology patients. Personalized evaluation and further research are essential to establish safe and effective protocols for oncology patients, maximizing therapeutic benefits while minimizing risks.

Biomaterial-assisted local oxygenation safeguards the prostimulatory phenotype and functions of human dendritic cells in hypoxia

Dendritic cells (DCs), professional antigen-presenting cells, function as sentinels of the immune system. DCs initiate and fine-tune adaptive immune responses by presenting antigenic peptides to B and T lymphocytes to mount an effective immune response against cancer and pathogens. However, hypoxia, a condition characterized by low oxygen (O2) tension in different tissues, significantly impacts DC functions, including antigen uptake, activation and maturation, migration, as well as T-cell priming and proliferation. In this study, we employed O2-releasing biomaterials (O2-cryogels) to study the effect of localized O2 supply on human DC phenotype and functions. Our results indicate that O2-cryogels effectively mitigate DC exposure to hypoxia under hypoxic conditions. Additionally, O2-cryogels counteract hypoxia-induced inhibition of antigen uptake and migratory activity in DCs through O2 release and hyaluronic acid (HA) mediated mechanisms. Furthermore, O2-cryogels preserve and restore DC maturation and co-stimulation markers, including HLA-DR, CD86, and CD40, along with the secretion of proinflammatory cytokines in hypoxic conditions. Finally, our findings demonstrate that the supplemental O2 released from the cryogels preserves DC-mediated T-cell priming, ultimately leading to the activation and proliferation of allogeneic CD3+ T cells. This work emphasizes the potential of local oxygenation as a powerful immunomodulatory agent to improve DC activation and functions in hypoxia, offering new approaches for cancer and infectious disease treatments.

Recent advances in the nanoarchitectonics of metal-organic frameworks for light-activated tumor therapy

Metal-organic frameworks (MOFs) have received extensive attention in tumor therapy because of their advantages, including large specific surface area, regular pore size, adjustable shape, and facile functionalization. MOFs are porous materials formed by the coordination bonding of metal clusters and organic ligands. This review summarized the most recent advancements in tumor treatment based on nMOFs. First, we discuss the classification of MOFs, which primarily include the series of isoreticular MOF (IRMOF), zeolitic imidazolate framework (ZIF), coordination pillared-layer (CPL), Materials of Institute Lavoisier (MIL), porous coordination network (PCN), University of Oslo (UiO) and Biological metal-organic frameworks (BioMOFs). Then, we discuss the use of nMOFs in antitumor therapy, including drug delivery strategies, photodynamic therapy (PDT), photothermal therapy (PTT), and combination therapy. Finally, the obstacles and opportunities in nMOFs are discussed.

Hyperbaric Oxygen Therapy Adjuvant Chemotherapy and Radiotherapy through Inhibiting Stemness in Glioblastoma

Glioblastoma multiforme (GBM) is the most common and deadliest primary brain tumor in adults. Despite the advances in GBM treatment, outcomes remain poor, with a 2-year survival rate of less than 5%. Hyperbaric oxygen (HBO) therapy is an intermittent, high-concentration, short-term oxygen therapy used to increase cellular oxygen content. In this study, we evaluated the effects of HBO therapy, alone or combined with other treatment modalities, on GBM in vitro and in vivo. In the in vitro analysis, we used a 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay to assess the effects of HBO therapy alone, a colony formation assay to analyze the effects of HBO therapy combined with radiotherapy and with temozolomide (TMZ), and a neurosphere assay to assess GBM stemness. In the in vivo analysis, we used immunohistochemical staining and in vivo bioluminescence imaging to assess GBM stemness and the therapeutic effect of HBO therapy alone or combined with TMZ or radiotherapy, respectively. HBO therapy did not affect GBM cell viability, but it did reduce the analyzed tumors' ability to form cancer stem cells. In addition, HBO therapy increased GBM sensitivity to TMZ and radiotherapy both in vitro and in vivo. HBO therapy did not enhance tumor growth and exhibited adjuvant effects to chemotherapy and radiotherapy through inhibiting GBM stemness. In conclusion, HBO therapy shows promise as an adjuvant treatment for GBM by reducing cancer stem cell formation and enhancing sensitivity to chemotherapy and radiotherapy.

Cancer Metabolism as a Therapeutic Target and Review of Interventions

Cancer is amenable to low-cost treatments, given that it has a significant metabolic component, which can be affected through diet and lifestyle change at minimal cost. The Warburg hypothesis states that cancer cells have an altered cell metabolism towards anaerobic glycolysis. Given this metabolic reprogramming in cancer cells, it is possible to target cancers metabolically by depriving them of glucose. In addition to dietary and lifestyle modifications which work on tumors metabolically, there are a panoply of nutritional supplements and repurposed drugs associated with cancer prevention and better treatment outcomes. These interventions and their evidentiary basis are covered in the latter half of this review to guide future cancer treatment.

The PRX-1/TLR4 axis promotes hypoxia-induced radiotherapy resistance in non-small cell lung cancer by targeting the NF-κB/p65 pathway

Hypoxic lung cancer cells are highly resistant to radiation. Peroxiredoxin-1 (PRX-1), a transcriptional coactivator that enhances the DNA-binding activity of serum reactive factor, has been identified as a target for radiotherapy sensitization, but the underlying molecular mechanism remains unclear. This study aimed to investigate the influence of PRX-1 on radiotherapy sensitivity in hypoxic tumors. Hypoxic lung cancer cells exhibited radiotherapy-resistant phenotypes after irradiation, including increased proliferation, DNA damage repair, cell migration, invasion and stemness. Radio-resistant hypoxic lung cancer cells showed high expression levels of PRX-1. Furthermore, we observed that PRX-1 bound to the promoter region of TRL4 (-300 to -600) and promoted its transcription and expression and that PRX-1/TRL4 activated the NF-κB/p65 signaling pathway. Increased radiotherapy resistance of hypoxic lung cancer cells increased their ability to proliferate, migrate, and maintain stemness in vivo and in vitro. These findings suggest that PRX-1/TRL4 could be used as a target for the treatment of radiotherapy-resistant lung cancer cells and further provide a theoretical basis for the clinical treatment of hypoxic lung cancer cells.

Near-infrared photodynamic and photothermal co-therapy based on organic small molecular dyes

Near-infrared (NIR) organic small molecule dyes (OSMDs) are effective photothermal agents for photothermal therapy (PTT) due to their advantages of low cost and toxicity, good biodegradation, and strong NIR absorption over a wide wavelength range. Nevertheless, OSMDs have limited applicability in PTT due to their low photothermal conversion efficiency and inadequate destruction of tumor regions that are nonirradiated by NIR light. However, they can also act as photosensitizers (PSs) to produce reactive oxygen species (ROS), which can be further eradicated by using ROS-related therapies to address the above limitations of PTT. In this review, the synergistic mechanism, composition, and properties of photodynamic therapy (PDT)-PTT nanoplatforms were comprehensively discussed. In addition, some specific strategies for further improving the combined PTT and PDT based on OSMDs for cancer to completely eradicate cancer cells were outlined. These strategies include performing image-guided co-therapy, enhancing tumor infiltration, increasing H2O2 or O2 in the tumor microenvironment, and loading anticancer drugs onto nanoplatforms to enable combined therapy with phototherapy and chemotherapy. Meanwhile, the intriguing prospects and challenges of this treatment modality were also summarized with a focus on the future trends of its clinical application.

Hyperbaric oxygen therapy as a complementary treatment in neuroblastoma - a narrative review

Neuroblastoma is the most frequently diagnosed cancer during the first year of life. This neoplasm originates from neural crest cells derived from the sympathetic nervous system, adrenal medulla, or paraspinal ganglia. The clinical presentation can vary from an asymptomatic mass to symptoms resulting from local invasion and/or spread of distant disease spread. The natural history of neuroblastoma is highly variable, ranging from relatively indolent biological behavior to a high-risk clinical phenotype with a dismal prognosis. Age, stage, and biological features are important prognostic risk stratification and treatment assignment prognostic factors. The multimodal therapy approach includes myeloablative chemotherapy, radiotherapy, immunotherapy, and aggressive surgical resection. Hyperbaric oxygen therapy (HBOT) has been proposed as a complementary measure to overcome tumor hypoxia, which is considered one of the hallmarks of this cancer treatment resistance. This article aims to review the relevant literature on the neuroblastoma pathophysiology, clinical presentation, and different biological and genetic profiles, and to discuss its management, focusing on HBOT.

Advances in hyperbaric oxygen to promote immunotherapy through modulation of the tumor microenvironment

Hyperbaric oxygen therapy is a relatively safe treatment method that has been used for a long time in the clinic. It has been proven that it can enhance the sensitivity of radiotherapy and photodynamic therapy for cancer. However, there are few studies on hyperbaric oxygen and immunotherapy. In this article, we summarize that hyperbaric oxygen therapy regulates the tumor microenvironment through various pathways such as improving tumor hypoxia, targeting hypoxia-inducing factors, and generating reactive oxygen species. The change in the tumor microenvironment ultimately affects the curative effect of immunotherapy. Therefore, hyperbaric oxygen can influence immunotherapy by regulating the tumor microenvironment, providing a direction for the future development of immunotherapy.

Hyperbaric Oxygen Therapy for Threatened Nipple-Sparing Mastectomy Flaps: An Adjunct for Flap Salvage

BACKGROUND

Nipple-sparing mastectomy (NSM) is emerging as the standard of care for treatment of breast cancer because of its oncologic safety and superior aesthetic outcomes. However, ischemia or necrosis of the skin flap and/or nipple-areola complex remain frequent complications. Hyperbaric oxygen therapy (HBOT) has emerged as a potential adjunct for flap salvage, although it is not currently a widely accepted practice. Here we review our institution's experience using a protocol of HBOT in patients with signs of flap ischemia or necrosis after NSM.

METHODS

Retrospective review identified all patients treated with HBOT at our institution's hyperbaric and wound care center because of signs of ischemia after NSM. Treatment parameters consisted of 90-minute dives at 2.0 atmosphere once or twice daily. Patients unable to tolerate dives were considered a treatment failure, whereas those lost to follow-up were excluded from analysis. Patient demographics, surgical characteristics, and treatment indications were recorded. Primary outcomes assessed were flap salvage (no operative revision), need for revision procedures, and treatment complications.

RESULTS

A total of 17 patients and 25 breasts met the inclusion criteria. The mean ± SD time to initiation of HBOT was 9.47 ± 12.7 days. The mean ± SD age was 46.7 ± 10.4 years, and mean ± SD follow-up time was 36.5 ± 25.6 days. Indications for NSM included invasive cancer (41.2%), carcinoma in situ (29.4%), and breast cancer prophylaxis (29.4%). Initial reconstruction included tissue-expander placement (47.1%), autologous reconstruction with deep inferior epigastric flaps (29.4%), and direct-to-implant reconstruction (23.5%). Hyperbaric oxygen therapy indications included ischemia or venous congestion for 15 breasts (60.0%) and partial thickness necrosis for 10 breasts (40.0%). Flap salvage was achieved in 22 of 25 breasts (88.0%). Reoperation was required for 3 breasts (12.0%). Hyperbaric oxygen therapy-related complications were observed in 4 patients (23.5%), which included 3 patients with mild ear pain and 1 patient with severe sinus pressure leading to treatment abortion.

CONCLUSIONS

Nipple-sparing mastectomy is an invaluable tool for breast and plastic surgeons to achieve oncologic and cosmetic goals. However, ischemia or necrosis of the nipple-areola complex or mastectomy skin flap remains frequent complications. Hyperbaric oxygen therapy has emerged as a possible intervention for threatened flaps. Our results demonstrate the utility of HBOT in this population to achieve excellent NSM flap salvage rates.

The Role of Hyperbaric Oxygen Therapy in the Treatment of Surgical Site Infections: A Narrative Review

Surgical site infections (SSIs) are among the most prevalent postoperative complications, with significant morbidity and mortality worldwide. In the past half century, hyperbaric oxygen therapy (HBOT), the administration of 100% oxygen intermittently under a certain pressure, has been used as either a primary or alternative therapy for the management or treatment of chronic wounds and infections. This narrative review aims to gather information and evidence supporting the role of HBOT in the treatment of SSIs. We followed the Scale for the Quality Assessment of Narrative Review Articles (SANRA) guidelines and scrutinized the most relevant studies identified in Medline (via PubMed), Scopus, and Web of Science. Our review indicated that HBOT can result in rapid healing and epithelialization of various wounds and has potential beneficial effects in the treatment of SSIs or other similar infections following cardiac, neuromuscular scoliosis, coronary artery bypass, and urogenital surgeries. Moreover, it was a safe therapeutic procedure in most cases. The mechanisms related to the antimicrobial activity of HBOT include direct bactericidal effects through the formation of reactive oxygen species (ROS), the immunomodulatory effect of HBOT that increase the antimicrobial effects of the immune system, and the synergistic effects of HBOT with antibiotics. We emphasized the essential need for further studies, especially randomized clinical trials and longitudinal studies, to better standardize HBOT procedures as well as to determine its full benefits and possible side effects.

Oxygen-generating biocatalytic nanomaterials for tumor hypoxia relief in cancer radiotherapy

Radiotherapy (RT), the most commonly used treatment method in clinics, shows unique advantages such as strong penetration, high energy intensity, and low systemic side effects. However, in vivo tumor hypoxia seriously hinders the therapeutic effect of RT. Hypoxia is a common characteristic of locally advanced solid tumor microenvironments, which leads to the proliferation, invasion and metastasis of tumor cells. In addition, oxygen consumption during RT will further aggravate tumor hypoxia, causing a variety of adverse side effects. In recent years, various biocatalytic nanomaterials (BCNs) have been explored to regulate and reverse tumor hypoxia microenvironments during RT. In this review, the most recent efforts toward developing oxygen-generating BCNs in relieving tumor hypoxia in RT are focused upon. The classification, engineering nanocatalytical activity of oxygen-generating BCNs and combined therapy based on these BCNs are systematically introduced and discussed. The challenges and prospects of these oxygen-generating BCNs in RT applications are also summarized.

Mitochondria Targeted AIE Probes for Cancer Phototherapy

In recent years, mitochondrion (powerhouse of the cells) gained lots of interest as one of the unorthodox targets for futuristic cancer therapy. As a result, novel small molecules were developed to damage and image mitochondria in cancer models. In this context, aggregation-induced emission probes (AIEgens) received immense attention due to their applications in mitochondria-targeted biosensing, imaging, and biomedical theranostics. On the other hand, phototherapy (photodynamic and photothermal) has emerged as a powerful alternative to manage cancer due to its less invasive nature. However, merging these two areas to engineer mitochondria-targeted phototherapeutic probes for cancer diagnosis and treatment has remained a major challenge. In this mini-review, we will outline the development of novel mitochondria-targeted small molecule AIEgens as imaging agents and photosensitizers for photodynamic therapy along with dual photodymanic-phototheramal therapy and chemo-photodynamic therapy. We will also highlight the current challenges in developing mitochondria-targeted photothermal therapy probes for future biomedical theranostic applications to manage cancer.

Supramolecular Photosensitizer Enables Oxygen-Independent Generation of Hydroxyl Radicals for Photodynamic Therapy

The highly oxygen-dependent nature of photodynamic therapy (PDT) limits its therapeutic efficacy against hypoxic solid tumors in clinics, which is an urgent problem to be solved. Herein, we develop an oxygen-independent supramolecular photodynamic agent that produces hydroxyl radical (•OH) by oxidizing water in the presence of intracellularly abundant pyruvic acid under oxygen-free conditions. A fluorene-substituted BODIPY was designed as the electron donor and coassembled with perylene diimide as the electron acceptor to form the quadruple hydrogen-bonded supramolecular photodynamic agent. Detailed mechanism studies reveal that intermolecular electron transfer and charge separation upon light irradiation result in an efficient generation of radical ion pairs. Under oxygen-free conditions, the cationic radicals directly oxidize water to generate highly cytotoxic •OH, and the anionic radicals transfer electrons to pyruvic acid, realizing the catalytic cycle. Thus, this photodynamic agent exhibited superb photocytotoxicity even under severe hypoxic environments and excellent in vivo antitumor efficacy on HeLa-bearing mouse models. This work provides a strategy for constructing oxygen-independent photodynamic agents, which opens up an avenue for effective PDT against hypoxic tumors.

Anti-Hypoxia Nanoplatforms for Enhanced Photosensitizer Uptake and Photodynamic Therapy Effects in Cancer Cells

Photodynamic therapy (PDT) holds great promise in cancer eradication due to its target selectivity, non-invasiveness, and low systemic toxicity. However, due to the hypoxic nature of many native tumors, PDT is frequently limited in its therapeutic effect. Additionally, oxygen consumption during PDT may exacerbate the tumor's hypoxic condition, which stimulates tumor proliferation, metastasis, and invasion, resulting in poor treatment outcomes. Therefore, various strategies have been developed to combat hypoxia in PDT, such as oxygen carriers, reactive oxygen supplements, and the modulation of tumor microenvironments. However, most PDT-related studies are still conducted on two-dimensional (2D) cell cultures, which fail to accurately reflect tissue complexity. Thus, three-dimensional (3D) cell cultures are ideal models for drug screening, disease simulation and targeted cancer therapy, since they accurately replicate the tumor tissue architecture and microenvironment. This review summarizes recent advances in the development of strategies to overcome tumor hypoxia for enhanced PDT efficiency, with a particular focus on nanoparticle-based photosensitizer (PS) delivery systems, as well as the advantages of 3D cell cultures.

Manipulation of metabolic pathways to promote stem-like and memory T cell phenotypes for immunotherapy

Utilizing the immune system's capacity to recognize and kill tumor cells has revolutionized cancer therapy in recent decades. Phenotypic study of antitumor T cells supports the principle that superior tumor control is achieved by cells with more long-lived memory or stem-like properties as compared to terminally differentiated effector cells. In this Mini-Review, we explore recent advances in profiling the different metabolic programs that both generate and define subsets of memory T cells. We additionally discuss new experimental approaches that aim to maximize the durability and sustained antitumor response associated with memory T cells within the unique immunosuppressive conditions of the tumor microenvironment, such as engineered attempts to overcome hypoxia-induced changes in mitochondrial function, the inhibitory effects of tumor metabolites, and exploitation of more recently-defined metabolic pathways controlling T cell memory fate such as glycogen metabolism.

Oxygen therapy accelerates apoptosis induced by selenium compounds via regulating Nrf2/MAPK signaling pathway in hepatocellular carcinoma

Selenium has good antitumor effects in vitro, but the hypoxic microenvironment in solid tumors makes its clinical efficacy unsatisfactory. We hypothesized that the combination with oxygen therapy might improve the treatment efficacy of selenium in hypoxic tumors through the changes of redox environment. In this work, two selenium compounds, Na₂SeO₃ and CysSeSeCys, were selected to interrogate their therapeutic effects on hepatocellular carcinoma (HCC) under different oxygen levels. In tumor-bearing mice, both selenium compounds significantly inhibited the tumor growth, and combined with oxygen therapy further reduced the tumor volume about 50 %. In vitro HepG2 cell experiments, selenium induced autophagy and delayed apoptosis under hypoxia (1 % O₂), while inhibited autophagy and accelerated apoptosis under hyperoxia (60 % O₂). We found that, in contrast to hypoxia, the hyperoxic environment facilitated the H₂Se, produced by the selenium metabolism in cells, to be rapidly oxidized to generate H₂O₂, leading to inhibit the expression level of Nrf2 and to increase that of phosphorylation of p38 and MKK4, resulting in inhibiting autophagy and accelerating apoptosis. Once the Nrf2 gene was knocked down, selenium compounds combined with hyperoxia treatment would further activate the MAPK signaling pathway and further increase apoptosis. These findings highlight oxygen can significantly enhance the anti-HCC effect of selenium compounds through regulating the Nrf2 and MAPK signaling pathways, thus providing novel therapeutic strategy for the hypoxic tumors and pave the way for the application of selenium in clinical treatment.

Modeling Preclinical Cancer Studies under Physioxia to Enhance Clinical Translation

Oxygen (O2) plays a key role in cellular homeostasis. O2 levels are tightly regulated in vivo such that each tissue receives an optimal amount to maintain physiologic status. Physiologic O2 levels in various organs range between 2% and 9% in vivo, with the highest levels of 9% in the kidneys and the lowest of 0.5% in parts of the brain. This physiologic range of O2 tensions is disrupted in pathologic conditions such as cancer, where it can reach as low as 0.5%. Regardless of the state, O2 tension in vivo is maintained at significantly lower levels than ambient O2, which is approximately 21%. Yet, routine in vitro cellular manipulations are carried out in ambient air, regardless of whether or not they are eventually transferred to hypoxic conditions for subsequent studies. Even brief exposure of hematopoietic stem cells to ambient air can cause detrimental effects through a mechanism termed extraphysiologic oxygen shock/stress (EPHOSS), leading to reduced engraftment capabilities. Here, we provide an overview of the effects of ambient air exposure on stem and non-stem cell subtypes, with a focus on recent findings that reveal the impact of EPHOSS on cancer cells.

Lower versus higher oxygenation targets in ICU patients with haematological malignancy - insights from the HOT-ICU trial

Background

Patients admitted to an intensive care unit (ICU) with active haematological malignancy and hypoxaemic respiratory failure have a high mortality. Oxygen supplementation is essential, but limited information exists on the optimum oxygenation targets in these patients.

Methods

This subgroup analysis was specified before completion of the Handling Oxygenation Targets in the ICU (HOT-ICU) trial. The trial investigated the effects of a lower (8 kPa) vs a higher (12 kPa) arterial oxygenation target and was stratified for active haematological malignancy, chronic obstructive pulmonary disease, and site. We here report the primary outcome (90-day mortality) and selected secondary outcomes in the subgroup of patients with active haematological malignancy.

Results

The HOT-ICU trial included 168 patients with active haematological malignancy; 82 were randomly allocated to an arterial oxygenation target of 8 kPa, and 86 to 12 kPa. At 90 days, 53/81 patients (65%) in the lower-oxygenation group and 47/86 patients (55%) in the higher-oxygenation group had died: adjusted relative risk 1.22 (95% confidence interval 0.95-1.56); at 1 year, the numbers were 58/81 (72%) vs 56/86 (65%): adjusted relative risk 1.11 (95% confidence interval 0.90-1.36). No statistically significant differences were found for any secondary outcomes.

Conclusion

In ICU patients with active haematological malignancies and hypoxaemic respiratory failure, we found a high mortality at 90 days and 1 year. Our results did not preclude clinically relevant benefits or harms of a lower oxygenation target in patients with active haematological malignancy. A randomised trial may, therefore, be worthwhile for these patients.

Clinical trial registration

NCT03174002.