Hyperbaric oxygen treatment for inflammatory bowel disease: a systematic review and analysis

Systematic review and dosage analysis: hyperbaric oxygen therapy efficacy in the treatment of posttraumatic stress disorder

Background

Studies of hyperbaric oxygen therapy (HBOT) treatment of mild traumatic brain injury persistent postconcussion syndrome in military and civilian subjects have shown simultaneous improvement in posttraumatic stress disorder (PTSD) or PTSD symptoms, suggesting that HBOT may be an effective treatment for PTSD. This is a systematic review and dosage analysis of HBOT treatment of patients with PTSD symptoms.

Methods

PubMed, CINAHL, and the Cochrane Systematic Review Database were searched from September 18 to November 23, 2023, for all adult clinical studies published in English on HBOT and PTSD. Randomized trials and studies with symptomatic outcomes were selected for final analysis and analyzed according to the dose of oxygen and barometric pressure on symptom outcomes. Outcome assessment was for statistically significant change and Reliable Change or Clinically Significant Change according to the National Center for PTSD Guidelines. Methodologic quality and bias were determined with the PEDro Scale.

Results

Eight studies were included, all with < 75 subjects/study, total 393 subjects: seven randomized trials and one imaging case-controlled study. Six studies were on military subjects, one on civilian and military subjects, and one on civilians. Subjects were 3-450 months post trauma. Statistically significant symptomatic improvements, as well as Reliable Change or Clinically Significant changes, were achieved for patients treated with 40-60 HBOTS over a wide range of pressures from 1.3 to 2.0 ATA. There was a linear dose-response relationship for increased symptomatic improvement with increasing cumulative oxygen dose from 1002 to 11,400 atmosphere-minutes of oxygen. The greater symptomatic response was accompanied by a greater and severe reversible exacerbation of emotional symptoms at the highest oxygen doses in 30-39% of subjects. Other side effects were transient and minor. In three studies the symptomatic improvements were associated with functional and anatomic brain imaging changes. All 7 randomized trials were found to be of good-highest quality by PEDro scale scoring.

Discussion

In multiple randomized and randomized controlled clinical trials HBOT demonstrated statistically significant symptomatic improvements, Reliable Changes, or Clinically Significant Changes in patients with PTSD symptoms or PTSD over a wide range of pressure and oxygen doses. The highest doses were associated with a severe reversible exacerbation of emotional symptoms in 30-39% of subjects. Symptomatic improvements were supported by correlative functional and microstructural imaging changes in PTSD-affected brain regions. The imaging findings and hyperbaric oxygen therapy effects indicate that PTSD can no longer be considered strictly a psychiatric disease.

Role of hyperbaric oxygen therapy in patients with inflammatory bowel disease

PURPOSE OF REVIEW

Hypoxia is a known contributor to inflammation in inflammatory bowel diseases (IBD), and a growing interest has emerged in pharmacologically targeting hypoxia response pathways to treat IBD. The most basic form of treatment for hypoxia is delivering higher amounts of oxygen to the intestinal mucosa. In this review, we summarize the evidence in support of hyperbaric oxygen therapy (HBOT), a mechanism to deliver high amounts of oxygen to tissue, for treating IBD.

RECENT FINDINGS

Two phase 2 clinical trials in hospitalized ulcerative colitis patients suffering from moderate-to-severe flares have demonstrated that HBOT improves responsiveness to steroids and avoidance of rescue medical and surgical therapy. Outpatient cohort studies in perianal fistulizing Crohn's disease and fistulizing complications of the pouch have demonstrated improved healing, particularly for complex fistulae. Several systematic reviews have now been completed, and HBOT has been observed to be well tolerated with low rates of adverse events.

SUMMARY

HBOT may be considered as an adjunctive treatment for hospitalized ulcerative colitis flares and Crohn's disease-related fistulae. Higher quality trials are needed to confirm efficacy.

Addition of hyperbaric oxygen therapy versus usual care alone for inflammatory bowel disease: A systematic review and meta-analysis

Objective

Inflammatory bowel disease (IBD) is a chronic idiopathic inflammatory disease that includes ulcerative colitis (UC) and Crohn's disease (CD). Hyperbaric oxygen therapy (HBOT) involves breathing pure oxygen in a pressurized environment. Existing literature suggests that HBOT may be an effective therapy for IBD, but a quantitative analysis is lacking. This study aims to estimate the adjunctive role of HBOT in treating IBD and lowering its recurrence rate.

Design

Systematic review and meta-analysis.

Methods

The Cochrane Library, EMBASE, PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database (VIP), and Wanfang databases were systematically searched by two reviewers independently. Meta-analyses were performed using Review Manager (RevMan, version 5.3). A random-effects model was applied due to the heterogeneity between studies.

Results

Twenty-nine out of the initially identified 606 articles were covered in this review, with a total of 2151 patients (2071 for UC and 80 for CD). No randomized data of HBOT for CD were included. Among UC patients, usual care plus HBOT were more likely to achieve a clinical response than usual care alone (risk ratio [RR], 1.24; 95% confidence interval (CI), 1.17 to 1.31; P < 0.001). Subgroup analysis showed that the number of HBOT sessions had no statistically significant effect on overall efficacy (P > 0.05). The pooled data showed a lower recurrence rate in the usual care plus HBOT group (RR, 0.35; 95% CI, 0.24 to 0.53; P < 0.001). The standardized mean difference in the serum tumor necrosis factor level between HBOT and non-HBOT groups was -2.13 (95% CI, -3.09 to -1.18; P < 0.001). No severe adverse events of HBOT were observed.

Conclusions

HBOT might be an effective and safe adjunctive treatment for IBD. Further studies are required to investigate the optimal protocol of HBOT in IBD treatment.

Enhanced oxidative phosphorylation of IgG plasma cells can contribute to hypoxia in the mucosa of active ulcerative colitis

Mucosal hypoxia is detected in the mucosa of ulcerative colitis (UC), however the mechanism and the cause of hypoxia is not fully understood, while a dense infiltration of plasma cells is observed in the inflamed mucosa of UC. When differentiating from a B cell to a plasma cell, the energy metabolism dramatically shifts from glycolysis to oxidative phosphorylation, which results in a large amount of oxygen consumption of the plasma cell. We hypothesized that the plasma cell infiltration into the inflamed mucosa contributes to the mucosal hypoxia in UC in part. We examined the association between mucosal hypoxia and plasma cell infiltration in UC. More IgG plasma cells (but not IgA plasma cells) were distributed, and the nuclear and cell sizes were enlarged in hypoxic mucosa compared to normoxic mucosa in UC. Oxidative phosphorylation signature genes of these IgG plasma cells were markedly upregulated compared to those of other lymphoid cells infiltrating the lamina propria of inflamed mucosa of UC. Enlarged IgG plasma cells, which increase in number in the inflamed mucosa of UC, can be related to the hypoxic state of the inflamed mucosa of UC.

Cardiac mitochondrial energetics of the Australasian red spiny lobster, Jasus edwardsii, when exposed to isoeugenol within the commercial anaesthetic AQUI-S

The anaesthetic isoeugenol has been used as metabolic suppressant for commercial transport of live lobsters in order to decrease energy expenditure aand improve survival. Given the central role of mitochondria in metabolism and structural similarities of isoeugenol to the mitochondrial electron carrier coenzyme Q, we explored the influence on mitochondrial function of isoeugenol. Mitochondrial function was measured using high resolution respirometry and saponin permeabilized heart fibres from the Australasian red spiny lobster, Jasus edwardsii. Relative to vehicle (polysorbate), isoeugenol inhibited respiration supported by complex I (CI) and cytochrome c oxidase (CCO). While complex II (CII), which also reduces coenzyme Q was largely unaffected by isoeugenol, respiration supported by CII when uncoupled was depressed. Titration of isoeugenol indicates that respiration through CI has a half inhibition constant (IC50) of 2.4±0.1 µM, and full inhibition constant IC100 of approximately 6.3 µM. These concentrations are consistent with those used for transport and euthanasia of J. edwardsii and indicates that CI is a possible target of isoeugenol like many other anaesthetics with quinone-like structures.

The Effectiveness and Safety of Hyperbaric Oxygen Therapy in Various Phenotypes of Inflammatory Bowel Disease: Systematic Review With Meta-analysis

BACKGROUND

Accumulating evidence suggests that hyperbaric oxygen therapy (HBOT) may be effective for inflammatory bowel disease (IBD). Our systematic review aimed to quantify the effectiveness and safety of HBOT in various IBD phenotypes.

METHODS

We performed a proportional meta-analysis. Multiple databases were systematically searched from inception through November 2020 without language restriction. We included studies that reported effectiveness and/or safety of HBOT in IBD. Weighted summary estimates with 95% confidence intervals (Cis) were calculated for clinical outcomes for each IBD phenotype using random-effects models. Study quality was assessed using the Cochrane evaluation handbook and National Institute of Health criteria.

RESULTS

Nineteen studies with 809 patients total were eligible: 3 randomized controlled trials and 16 case series. Rates of clinical remission included 87% (95% CI, 10-100) for ulcerative colitis (n = 42), 88% (95% CI, 46-98) for luminal Crohn's disease (CD, n = 8), 60% (95% CI, 40-76) for perianal CD (n = 102), 31% (95% CI, 16-50) for pouch disorders (n = 60), 92% (95% CI, 38-100) for pyoderma gangrenosum (n = 5), and 65% (95% CI, 10-97) for perianal sinus/metastatic CD (n = 7). Of the 12 studies that reported on safety, 15% of patients (n = 30) had minor adverse events. Study quality was low in the majority of studies due to an absence of comparator arms, inadequate description of concomitant interventions, and/or lack of objective outcomes.

CONCLUSIONS

Limited high-quality evidence suggests that HBOT is safe and associated with substantial rates of clinical remission for multiple IBD phenotypes. Well-designed randomized controlled trials are warranted to confirm the benefit of HBOT in IBD.

Hyperbaric oxygen therapy in inflammatory bowel disease: a systematic review and meta-analysis

BACKGROUND

Translational data suggest a potential role of hyperbaric oxygen therapy (HBOT) in a subset of patients with inflammatory bowel disease (IBD). We performed a systematic review and meta-analysis for the efficacy and safety of HBOT in IBD.

METHODS

We searched Pubmed, Embase and CENTRAL to identify studies reporting the efficacy of HBOT in ulcerative colitis or Crohn's disease. We pooled the response rates for HBOT in ulcerative colitis and Crohn's disease separately.

RESULTS

A total 18 studies were included in the systematic review and 16 in the analysis. The overall response rate of HBOT in ulcerative colitis was 83.24% (95% confidence interval: 61.90-93.82), while the response in Crohn's disease was 81.89 (76.72-86.11). The results of randomized trials for HBOT as adjuvant therapy in ulcerative colitis were conflicting. The complete healing of fistula in fistulizing Crohn's disease was noted 47.64% (22.05-74.54), while partial healing was noted in 34.29% (17.33-56.50%). Most of the adverse events were minor.

CONCLUSION

Observational studies suggest benefit of use of HBOT in ulcerative colitis flares and Crohn's disease. However, adequately powered randomized trials are needed to draw a definite conclusion.

A Review of Hyperbaric Oxygen Therapy for Inflammatory Bowel Disease

IBD (inflammatory bowel disease) characterized by chronic inflammation of the gastrointestinal (GI) tract is one of the chronic diseases the prevalence of which has been increasing globally. In the past few decades, significant improvements were made in the treatments relating to IBD which have reduced the hospitalization and mortality rates; however, there is still room for improvement with other alternative therapies. HBOT (hyperbaric oxygen treatment) is one of the effective therapies used in treating various conditions including wounds, decompression sickness, stroke, etc. Several studies have reported the role of HBOT as an adjunctive treatment to IBD, while adopting conventional treatment procedures. There is an increasing trend of research in this particular area. Studies have shown that HBOT reflects its therapeutic effect by controlling inflammation, reducing oxidation stress, improving the process of cleaning damaged cells and recruiting the cells involved in repair; thereby improving the immunity response system. In this context, the purpose of this review is to summarize past clinical and experimental studies and to understand the role of hyperbaric treatment for IBD. The findings from the review have suggested that hyperbaric therapy can be an effective adjunctive approach for IBD, based on which some ideas for future clinical and research work are provided.

Meisoindigo attenuates dextran sulfate sodium-induced experimental colitis via its inhibition of TAK1 in macrophages

At present, inflammatory bowel disease (IBD) seriously threatens human health, and its treatment is a huge challenge for people. In our studies, we found that meisoindigo, a derivative of indirubin, significantly ameliorated dextran sulfate sodium (DSS)-induced experimental colitis in mice. Meisoindigo treatment markedly elevated the level of glutathione, while suppressed the activities of alkaline phosphatase and myeloperoxidase in colonic tissues. Moreover, the mRNA expression of vascular cell adhesion molecule 1, intercellular adhesion molecule 1, cyclooxygenase-2 which are important colitis-related molecules and the levels of the inflammatory cytokines interleukin (IL)-18, IL-1β, IL-6, tumor necrosis factor (TNF)-α and inducible nitric oxide synthase (iNOS) were suppressed dose-dependently following treatment with meisoindigo. Immunofluorescence results indicated that meisoindigo inhibited macrophage infiltration and nuclear factor (NF)-κB activation in colons from DSS-treated mice. Therefore, mouse RAW264.7 and human THP-1 cells were treated with lipopolysaccharide (LPS) alone or combined adenosine triphosphate to activate NF-κB pathway in vitro. It was shown that meisoindigo reduced the elevated levels of NO, IL-18, IL-1β and TNF-α after LPS treatment in both cells. In addition, meisoindigo showed inhibitory effects on NF-κB by using a luciferase reporter gene that depends on NF-κB. Through molecular docking, microscale thermophoresis and cellular thermal shift assay. It was further found that meisoindigo targeted transforming growth factor β activated kinase-1 (TAK1), which is an important regulator in the upstream of NF-κB pathway. In conclusion, our findings show that meisoindigo can alleviate IBD effectively at low doses, and negatively regulate proinflammatory responses by inhibiting the activation of TAK1, which provides new ideas for clinical anti-inflammatory therapy.

Adjunctive Hyperbaric Oxygen Therapy in Refractory Crohn's Disease: An Observational Study

Background and Aims

Patients may experience complications of Crohn's disease (CD) even when treated with optimal medical therapy strategies. Previous data have shown the efficacy of hyperbaric oxygen therapy (HBOT) in the management of complicated CD. However, there is no consensus regarding the optimal number of sessions or duration of treatment regimens. The aim of the present study was to investigate the efficacy of HBOT in CD patients who were refractory to conventional medical management.

Methods

This study included patients who underwent HBOT for the treatment of the following complications: perianal fistulizing Crohn's disease (pCD), enterocutaneous fistulas (ECF), or pyoderma gangrenosum (PG). Complete healing was defined as the closure of external orifice and the absence of active draining (in pCD), complete wound healing (in PG), and granulation or complete wound epithelialization with no enteric draining (in ECF). The persistence of draining and the absence of wound granulation were defined as incomplete healing.

Results

Forty patients were included. The mean CD duration was 10.6 ± 5.8 years. pCD comprised most of the included patients (25/62.5%), followed by ECF (n = 13/32.5%) and PG (n = 6/15%). In two patients (5%), a combination of ECF and PG was diagnosed, and in one patient (2.5%), all three complications were observed. A total of 32 patients (82.5%) had complete healing. Patients with PG had the highest healing rates (100%), followed by those with ECF (84.6%) and pCD (80%).

Conclusions

Adjunctive HBO was associated with significant healing rates for CD-associated complications such as pCD, ECF, and PG.

Barrier integrity and chronic inflammation mediated by HIF-1 impact on intestinal tumorigenesis

Colorectal cancer ranks among the top three most frequent malignancies in the world. While overall incidence and mortality of colorectal cancer has substantially decreased in recent years, tumor subtypes with poor response rates to standard antiproliferative therapies remain particularly challenging. Hypoxia in the microenvironment of solid tumors is associated with malignant progression, e.g. local invasion, systemic spread and therapy resistance. A detailed molecular understanding of hypoxia's role for the pathobiology of colorectal cancer is a prerequisite to design and evaluate the consequences of interference with hypoxic signaling for the progression of this cancer type. Here, we summarize the current knowledge about the role of hypoxia-inducible factor 1, an essential molecular mediator of the hypoxic response, for colorectal cancer pathogenesis. Special attention is given to intestinal microbiota, gut barrier integrity and chronic inflammation as these are of pivotal importance for intestinal tumorigenesis and noticeably associated with hypoxic signaling.

Wound healing of metastatic perineal Crohn's disease using hyperbaric oxygen therapy: A case series

Background

Metastatic Crohn’s disease (CD) is a rare manifestation of CD. It involves inflammatory skin lesions with histopathological findings (granulomas) similar to CD, without connection to the gastrointestinal tract. Hyperbaric oxygen therapy (HBO) has been suggested as a possible treatment option.

Objective

This study aimed to identify and treat a consecutive series of patients with biopsy-proven metastatic CD and monitor wound healing using prospectively acquired outcomes.

Methods

Pathology results of all patients with ongoing perineal wound-healing problems after proctectomy between 2005 and 2018 at the Amsterdam University Medical Centre were assessed for metastatic CD. Patients with a biopsy-proven diagnosis of perineal metastatic CD were offered HBO (40 daily sessions of 100% oxygen at 2.4 atmosphere absolute). Wound healing was monitored using photographs and standardised questionnaires (the Inflammatory Bowel Disease Questionnaire, EuroQol Visual Analogue Scale and the Female Sexual Function Index) at baseline and 1 and 3 months after HBO.

Results

Out of 13 patients in the cohort with persisting perineal wounds after proctectomy, six (46%) had biopsy results consistent with metastatic CD. Of these, three accepted treatment with HBO. All three patients were female. One patient had complete healing of her perineal wound; another patient showed initial improvement but had a flare of luminal and perineal disease at the 3-month follow-up. The third patient showed improvement solely in the questionnaires, with higher scores on all three questionnaires.

Conclusion

A high rate of metastatic CD was found in patients with ongoing wound-healing problems after proctectomy, implying that the disease might not be as rare in these selected patients as previously thought. HBO might be beneficial in the treatment of metastatic CD.

Advances in Perianal Disease Associated with Crohn's Disease-Evolving Approaches

Perianal diseases, common complications of Crohn's disease, are difficult to diagnose/manage. Patients with perianal Crohn's disease suffer from persistent pain and drainage, recurrent perianal sepsis, impaired quality of life, and financial burden. Conventional medical and surgical therapies carry risk of infection, myelosuppression, incontinence, disease recurrence. Although the phenotype of Crohn's disease has been extensively studied, reported outcomes are inconsistent. Endoanal ultrasonography is also becoming popular because of low cost and ability to acquire images in real time. Emerging management strategies for treatment including laser therapy, local injection of agents, use of hyperbaric oxygen, and stem cell therapy, have demonstrated efficacy.

Hyperbaric Oxygen Increases Stem Cell Proliferation, Angiogenesis and Wound-Healing Ability of WJ-MSCs in Diabetic Mice

Hyperbaric oxygen therapy (HBOT) is effective for the medical treatment of diverse diseases, infections, and tissue injury. In fact, in recent years there is growing evidence on the beneficial effect of HBOT on non-healing ischemic wounds. However, there is still yet discussion on how this treatment could benefit from combination with regenerative medicine strategies. Here we analyzed the effects of HBOT on three specific aspects of tissue growth, maintenance, and regeneration: (i) modulation of adult rodent (Mus musculus) intestinal stem cell turnover rates; (ii) angiogenesis dynamics during the development of the chorio-allantoic membrane (CAM) in Gallus gallus embryos; (iii) and wound-healing in a spontaneous type II diabetic mouse model with a low capacity to regenerate skin. To analyze these aspects of tissue growth, maintenance, and regeneration, we used HBOT alone or in combination with cellular therapy. Specifically, Wharton Jelly Mesenchymal Stem cells (WJ-MSC) were embedded in a commercial collagen-scaffold. HBOT did not affect the metabolic rate of adult mice nor of chicken embryos. Notwithstanding, HBOT modified the proliferation rate of stem cells in the mice small intestinal crypts, increased angiogenesis in the CAM, and improved wound-healing and tissue repair in diabetic mice. Moreover, our study demonstrates that combining stem cell therapy and HBOT has a collaborative effect on wound-healing. In summary, our data underscore the importance of oxygen tension as a regulator of stem cell biology and support the potential use of oxygenation in clinical treatments.

Anti-Inflammatory Effects of Fargesin on Chemically Induced Inflammatory Bowel Disease in Mice

Fargesin is a bioactive lignan from Flos Magnoliae, an herb widely used in the treatment of allergic rhinitis, sinusitis, and headache in Asia. We sought to investigate whether fargesin ameliorates experimental inflammatory bowel disease (IBD) in mice. Oral administration of fargesin significantly attenuated the symptoms of dextran sulfate sodium (DSS)-induced colitis in mice by decreasing the inflammatory infiltration and myeloperoxidase (MPO) activity, reducing tumor necrosis factor (TNF)-α secretion, and inhibiting nitric oxide (NO) production in colitis mice. The degradation of inhibitory κBα (IκBα), phosphorylation of p65, and mRNA expression of nuclear factor κB (NF-κB) target genes were inhibited by fargesin treatment in the colon of the colitis mice. In vitro, fargesin blocked the nuclear translocation of p-p65, downregulated the protein levels of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2), and dose-dependently inhibited the activity of NF-κB-luciferase in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Taken together, for the first time, the current study demonstrated the anti-inflammatory effects of fargesin on chemically induced IBD might be associated with NF-κB signaling suppression. The findings may contribute to the development of therapies for human IBD by using fargesin or its derivatives.

Macrophages-common culprit in obesity and asthma

Macrophages are essential innate immune cells that also regulate local metabolism. Endogenous or exogenous stimuli may polarize macrophages toward phenotypes that serve distinct innate immunological metabolic functions. IFN-γ or lipopolysaccharide (LPS) polarizes macrophages toward the M1, or "classically activated" phenotype that participates in defense against intracellular pathogens. IL-4, IL-13, or chitin polarizes macrophages toward the M2, or "alternatively activated" phenotype, which defends against multicellular nematodes and fungi. As macrophages polarize in local environments, M1 and M2 macrophages may coexist in different organs and may differentially affect asthma and obesity, two comorbid diseases where polarized macrophages contribute to their pathogenesis. While M1 macrophages are considered beneficial in asthma and contribute to the pathology of obesity, M2 macrophages contribute to the pathology of asthma, but limit metabolic syndrome associated with obesity. Here, we discuss the roles for M1 and M2 macrophages in asthma and obesity, and propose a model by which M1-mediated inflammation in adipose tissue enhances M2-mediated inflammation in the asthmatic lung.

Supplemental oxygen therapy does not affect the systemic inflammatory response to acute myocardial infarction

BACKGROUND

Oxygen therapy has been used routinely in normoxemic patients with suspected acute myocardial infarction (AMI) despite limited evidence supporting a beneficial effect. AMI is associated with a systemic inflammation. Here, we hypothesized that the inflammatory response to AMI is potentiated by oxygen therapy.

METHODS

The DETermination of the role of Oxygen in suspected Acute Myocardial Infarction (DETO2X-AMI) multicentre trial randomized patients with suspected AMI to receive oxygen at 6 L min^-1 for 6-12 h or ambient air. For this prespecified subgroup analysis, we recruited patients with confirmed AMI from two sites for evaluation of inflammatory biomarkers at randomization and 5-7 h later. Ninety-two inflammatory biomarkers were analysed using proximity extension assay technology, to evaluate the effect of oxygen on the systemic inflammatory response to AMI.

RESULTS

Plasma from 144 AMI patients was analysed whereof 76 (53%) were randomized to oxygen and 68 (47%) to air. Eight biomarkers showed a significant increase, whereas 13 were decreased 5-7 h after randomization. The inflammatory response did not differ between the two treatment groups neither did plasma troponin T levels. After adjustment for increase in troponin T over time, age and sex, the release of inflammation-related biomarkers was still similar in the groups.

CONCLUSIONS

In a randomized controlled setting of normoxemic patients with AMI, the use of supplemental oxygen did not have any significant impact on the early release of systemic inflammatory markers.

The efficacy of hyperbaric oxygen in hemorrhagic stroke: experimental and clinical implications

Hemorrhagic stroke, accounting for 10-30% of stroke cases, carries high rates of morbidity and mortality. This review presents the current knowledge on the efficacy of hyperbaric oxygen (HBO)-based modalities in the preclinical research on hemorrhagic stroke. Both preconditioning and post-treatment with HBO are considered as prospective therapeutic options. High efficacy of HBO therapy (HBOT) for brain hemorrhage has been noted. We found that moderate hyperbaric pressures appear optimal for therapeutic effect, while the therapeutic window of opportunity is short. HBO preconditioning offers more modest neuroprotective benefit as compared to HBO post-treatment for experimental intracerebral hemorrhage. We advocate for mandatory calculations of percent changes in the experimentally investigated indexes of HBO effectiveness and stress the need to design new clinical trials on HBO for hemorrhagic stroke.

Chronic Diseases as Barriers to Oxygen Delivery: A Unifying Hypothesis of Tissue Reoxygenation Therapy

Modern medical practice has resulted in the accumulation of a growing number of incurable chronic diseases, many of which are inflammatory in nature. Inflammation establishes a hypoxic microenvironment within tissues, a condition of inflammatory hypoxia (IH). Tissues thus affected become severely compromised, are unable to elicit adaptive responses and eventually develop fibrosis and fixed microvascular deficits. Previous work has demonstrated that tissue hypoxia exits even within the simple human model of self-resolving inflammation, the tuberculin reaction. Failed resolution of IH establishes a vicious cycle within tissues that perpetuates tissue hypoxia and resists standard drug therapies. Diseases such as sepsis, chronic cutaneous wounds, kidney disease, traumatic brain injury, solid tumors, inflammatory bowel disease, and chronic bacterial infections (urinary tract infection, cystic fibrosis) are tissue specific manifestations of chronic IH. Successful reversal of IH, through tissue re-oxygenation therapy (TROT), will break this vicious cycle and restore tissue homeostasis. The examples of solid tumors and inflammatory bowel disease are presented to illustrate a theoretical framework to support this hypothesis. Re-oxygenation of compromised tissues must occur before successful treatment of these diverse chronic disease s can be expected.

Anti-Inflammatory Effects of Hyperbaric Oxygenation during DSS-Induced Colitis in BALB/c Mice Include Changes in Gene Expression of HIF-1α, Proinflammatory Cytokines, and Antioxidative Enzymes

Reactive oxygen species (ROS) and nitrogen species have an indispensable role in regulating cell signalling pathways, including transcriptional control via hypoxia inducible factor-1α (HIF-1α). Hyperbaric oxygenation treatment (HBO₂) increases tissue oxygen content and leads to enhanced ROS production. In the present study DSS-induced colitis has been employed in BALB/c mice as an experimental model of gut mucosa inflammation to investigate the effects of HBO₂ on HIF-1α, antioxidative enzyme, and proinflammatory cytokine genes during the colonic inflammation. Here we report that HBO₂ significantly reduces severity of DSS-induced colitis, as evidenced by the clinical features, histological assessment, impaired immune cell expansion and mobilization, and reversal of IL-1β, IL-2, and IL-6 gene expression. Gene expression and antioxidative enzyme activity were changed by the HBO₂ and the inflammatory microenvironment in the gut mucosa. Strong correlation of HIF-1α mRNA level to GPx1, SOD1, and IL-6 mRNA expression suggests involvement of HIF-1α in transcriptional regulation of these genes during colonic inflammation and HBO₂. This is further confirmed by a strong correlation of HIF-1α with known target genes VEGF and PGK1. Results demonstrate that HBO₂ has an anti-inflammatory effect in DSS-induced colitis in mice, and this effect is at least partly dependent on expression of HIF-1α and antioxidative genes.

Hyperbaric oxygen therapy stimulates colonic stem cells and induces mucosal healing in patients with refractory ulcerative colitis: a prospective case series

BACKGROUND

Hyperbaric oxygen (HBO) is used as part of treatment in a variety of clinical conditions. Its use in the treatment of ulcerative colitis has been reported in few clinical reports.

OBJECTIVE

We report the effect of HBO on refractory ulcerative colitis exploring one potential mechanism of action.

DESIGN

A review of records of patients with refractory ulcerative colitis who received HBO was conducted. Clinical and histopathological scoring was utilised to evaluate the response to HBO therapy (HBOT).

RESULTS

All patients manifested clinical improvement by the 40th cycle of HBOT. The median number of stool frequency dropped from seven motions/day (range=3-20) to 1/day (range=0.5-3), which was significant (z=-4.6, p<0.001). None of the patients manifested persistent blood passage after HBOT (z=-3.2, p=0.002). The severity index significantly improved after HBOT (z=-4.97, p<0.001). Histologically, a significant reduction of the scores of activity was recorded accompanied by a significant increase in the proliferating cell nuclear antigen labelling index of the CD44 cells of the colonic mucosa (p=0.001).

CONCLUSIONS

HBOT is effective in the setting of refractory ulcerative colitis. The described protocol is necessary for successful treatment. HBOT stimulates colonic stem cells to promote healing.

Combining infliximab, anti-MAP and hyperbaric oxygen therapy for resistant fistulizing Crohn's disease

Background:

Fistulizing Crohn's disease (CD) presents a therapeutic challenge as fistulae are notoriously difficult to heal. Mycobacterium avium ss paratuberculosis (MAP) treatment in CD is gaining attention.

Aim:

We evaluated healing of CD fistula(e) using a novel combination therapy.

Study:

Nine consecutive patients who failed to heal fistulae on conventional treatment including anti-TNF, were treated with at least three doses of infliximab, 18–30 courses of hyperbaric oxygen therapy and anti-MAP antibiotics comprising rifabutin, clarithromycin and clofazimine.

Results:

All patients achieved complete healing of fistulae by 6–28 weeks and follow-up for mean 18 months.

Conclusion:

Combining infliximab, hyperbaric oxygen therapy and anti-MAP, seems to enable healing of recalcitrant fistulae and although a small case series, all nine patients achieved complete healing.

Lay abstract: Nine consecutive patients with Crohn's disease and fistulae were treated with a special combination of infliximab, numerous hyperbaric oxygen sessions and combined antibiotics including rifabutin, clofazimine and clarithromycin as the base antibiotic combination – called anti-Mycobacterium avium ss paratuberculosis (MAP) therapy. At between 6 weeks and 6 months all fistulae healed – included rectovaginal – so that the skin was dry and there was no discharge and no need to wear a pad. Their Crohn's symptoms of diarrhea, urgency and bleeding also resolved. Continuation with anti-MAP therapy alone maintained healing although one patient who ceased the anti-MAP therapy had a relapse.

HBO: a possible supplementary therapy for oral potentially malignant disorders

Oral potentially malignant disorders (OPMDs) are chronic inflammatory diseases in which cells suffer hypoxia referring to deprivation of adequate oxygen supply. Hyperbaric oxygen treatment (HBO), which can increase oxygen tension and delivery to oxygen-deficient tissue, is a supplementary therapy to improve or cure disorders involving hypoxia. Although the applications of HBO in wound healings, acute ischemic stroke, radiation-induced soft tissue injury and cancers are extensively reported, there are only few studies on their effect in OPMDs. Not only does HBO furnish oxygen-it also possesses potent anti-inflammatory properties. At the cellular level, HBO can decrease lymphocyte proliferation and promote apoptosis of fibroblasts. At the molecular level, it can decrease expression of HIF, ICAM-1, TNF-α, TGF-β, and IFN-γ, as well as increase vascular VEGF expression and angiogenesis. Thus, we hypothesize that HBO may contribute to treat OPMDs, including oral lichen planus, oral leukoplakia, and oral submucous fibrosis both at the cellular level and the molecular level, and that it would be a safe and inexpensive therapeutic strategy.

Healing under pressure: hyperbaric oxygen and myocutaneous flap repair for extreme persistent perineal sinus after proctectomy for inflammatory bowel disease

AIM

Persistent perineal sinus (PPS) following proctectomy for inflammatory bowel disease affects about 50% of patients. Up to 33% of cases of PPS remain unhealed at 12 months and the most refractory cases are unhealed at 24 months despite optimal conventional therapy. Reports of hyperbaric oxygen therapy (HBOT) for chronic wounds and Crohn's perianal disease led us to explore perioperative HBOT with rectus abdominis myocutaneous (RAM) flap repair in a highly selected group of patients with extreme PPS who had failed all other interventions.

METHOD

Patients with extreme PPS received preoperative HBOT (a 90-min session at 2.2-2.4 atmospheres, five times per week for 5-6 weeks, for a total of up to 30 sessions), before abdominoperineal PPS excision and perineal reconstruction with vertical or transverse RAM flap repair within 2-4 weeks of completing HBOT. Postoperative HBOT (10 further 90-min sessions) was administered within 2 weeks where practicable.

RESULTS

Between 2007 and 2011, four patients with extreme PPS underwent RAM flap repair with preoperative HBOT; two also received postoperative HBOT. The median (range) duration of PPS before HBOT was 88.5 (23-156) months. All patients had previously failed multiple (5 to > 35) surgical procedures. Complete healing occurred in all patients at a median (range) follow-up of 2.5 (2-3) months. There were no further hospital admissions for PPS at a median (range) follow-up of 35 (8-64) months.

CONCLUSION

Hyperbaric oxygen therapy combined with PPS excision and perineal reconstruction with a RAM flap led to complete perineal healing in four patients with extreme PPS and appears a safe and effective extension to the therapeutic pathway for exceptionally treatment-refractory PPS.

Hyperbaric oxygen therapy does not improve the effects of standardized treatment in a severe attack of ulcerative colitis: a prospective randomized study

BACKGROUND AND AIMS

Complementary therapy options are needed in the treatment of active ulcerative colitis (UC). Hyperbaric oxygen therapy (HBOT) has been shown to have positive effects in experimental models of colitis and perianal Crohn's disease.

METHODS

In the present prospective randomized open-label study, HBOT in addition to conventional medical treatment was compared with conventional treatment alone. The primary objective in this study was improved clinical outcome evaluated by Mayo score, laboratory tests and fecal weight. The secondary objectives were improvement in health-related quality of life, avoidance of colectomy and evaluation of HBOT safety.

RESULTS

The authors found no statistically significant differences between the treatment groups in any of the assessed variables.

CONCLUSION

The study results do not support the use of HBOT as a treatment option in a severe attack of UC.

Role of hypoxic injury in pathophysiology of intestinal mucosal inflammation

Hypoxia influences the normal metabolism of cells and normal functions of organs, eventually causing diseases. Various degrees of hypoxia can be seen in the intestinal mucosa of both experimental mouse models and patients with inflammatory bowel disease (IBD), whose oxygen supply and oxygen consumption are damaged. A number of hypoxia inducible factors, such as HIF-1, HIF-2 and HIF-3, can regulate different physiological responses via different mechanisms. Proline hydroxylasedomain (PHD) is a two-dioxygenase oxygen sensor that can mediate degradation of proline residues of HIFs. IBD is closely related to hypoxia. In recent years, researchers have paid more attention to improving the body's reaction to hypoxia in IBD, which is considered a novel treatment concept. This review will analyze the role of hypoxic injury in the pathophysiology of intestinal mucosal inflammation in IBD.

Hyperbaric oxygen treatment in autism spectrum disorders

Traditionally, hyperbaric oxygen treatment (HBOT) is indicated in several clinical disorders include decompression sickness, healing of problem wounds and arterial gas embolism. However, some investigators have used HBOT to treat individuals with autism spectrum disorders (ASD). A number of individuals with ASD possess certain physiological abnormalities that HBOT might ameliorate, including cerebral hypoperfusion, inflammation, mitochondrial dysfunction and oxidative stress. Studies of children with ASD have found positive changes in physiology and/or behavior from HBOT. For example, several studies have reported that HBOT improved cerebral perfusion, decreased markers of inflammation and did not worsen oxidative stress markers in children with ASD. Most studies of HBOT in children with ASD examined changes in behaviors and reported improvements in several behavioral domains although many of these studies were not controlled. Although the two trials employing a control group reported conflicting results, a recent systematic review noted several important distinctions between these trials. In the reviewed studies, HBOT had minimal adverse effects and was well tolerated. Studies which used a higher frequency of HBOT sessions (e.g., 10 sessions per week as opposed to 5 sessions per week) generally reported more significant improvements. Many of the studies had limitations which may have contributed to inconsistent findings across studies, including the use of many different standardized and non-standardized instruments, making it difficult to directly compare the results of studies or to know if there are specific areas of behavior in which HBOT is most effective. The variability in results between studies could also have been due to certain subgroups of children with ASD responding differently to HBOT. Most of the reviewed studies relied on changes in behavioral measurements, which may lag behind physiological changes. Additional studies enrolling children with ASD who have certain physiological abnormalities (such as inflammation, cerebral hypoperfusion, and mitochondrial dysfunction) and which measure changes in these physiological parameters would be helpful in further defining the effects of HBOT in ASD.