Systematic review: The safety and efficacy of hyperbaric oxygen therapy for inflammatory bowel disease

Hyperbaric oxygen therapy ameliorates intestinal and systematic inflammation by modulating dysbiosis of the gut microbiota in Crohn's disease

BACKGROUND

Dysbiosis of the gut microbiota is pivotal in Crohn's disease (CD) and modulated by host physiological conditions. Hyperbaric oxygen therapy (HBOT) is a promising treatment for CD that can regulate gut microbiota. The relationship between HBOT and the gut microbiota in CD remains unknown.

METHODS

CD patients were divided into an HBOT group (n = 10) and a control group (n = 10) in this open-label prospective interventional study. The fecal samples before and after HBOT were used for 16 S rRNA gene sequencing and fecal microbiota transplantation (FMT). A colitis mouse model was constructed using dextran sulfate sodium, and intestinal and systematic inflammation was evaluated. The safety and long-term effect of HBOT were observed.

RESULTS

HBOT significantly reduced the level of C-reactive protein (CRP) (80.79 ± 42.05 mg/L vs. 33.32 ± 18.31 mg/L, P = 0.004) and the Crohn's Disease Activity Index (CDAI) (274.87 ± 65.54 vs. 221.54 ± 41.89, P = 0.044). HBOT elevated the declined microbial diversity and ameliorated the altered composition of gut microbiota in patients with CD. The relative abundance of Escherichia decreased, and that of Bifidobacterium and Clostridium XIVa increased after HBOT. Mice receiving FMT from donors after HBOT had significantly less intestinal inflammation and serum CRP than the group before HBOT. HBOT was safe and well-tolerated by patients with CD. Combined with ustekinumab, more patients treated with HBOT achieved clinical response (30%vs.70%, P = 0.089) and remission (20%vs.50%, P = 0.160) at week 4.

CONCLUSIONS

HBOT modulates the dysbiosis of gut microbiota in CD and ameliorates intestinal and systematic inflammation. HBOT is a safe option for CD and exhibits a promising auxiliary effect to ustekinumab.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2200061193. Registered 15 June 2022, https://www.chictr.org.cn/showproj.html?proj=171605 .

EFFECTS OF HYPERBARIC OXYGEN THERAPY ON INTESTINAL ISCHEMIA-REPERFUSION AND ITS MECHANISM

ABSTRACT

Ischemia can cause reversible or irreversible cell or tissue damage, and reperfusion after ischemia not only has no therapeutic effect but also aggravates cell damage. Notably, gut tissue is highly susceptible to ischemia-reperfusion (IR) injury under many adverse health conditions. Intestinal IR (IIR) is an important pathophysiological process in critical clinical diseases. Therefore, it is necessary to identify better therapeutic methods for relieving intestinal ischemia and hypoxia. Hyperbaric oxygenation refers to the intermittent inhalation of 100% oxygen in an environment greater than 1 atm pressure, which can better increase the oxygen level in the tissue and change the inflammatory pathway. Currently, it can have a positive effect on hypoxia and ischemic diseases. Related studies have suggested that hyperbaric oxygen can significantly reduce ischemia-hypoxic injury to the brain, spinal cord, kidney, and myocardium. This article reviews the pathogenesis of IR and the current treatment measures, and further points out that hyperbaric oxygen has a better effect in IR. We found that not only improved hypoxia but also regulated IR induced injury in a certain way. From the perspective of clinical application, these changes and the application of hyperbaric oxygen therapy have important implications for treatment, especially IIR.

Efficacy and Safety of Hyperbaric Oxygen Therapy in Fistulizing Crohn's Disease: A Systematic Review and Meta-analysis

BACKGROUND

Hyperbaric oxygen therapy (HBOT) delivers 100% oxygen in a pressurized chamber, increasing tissue oxygen levels and regulating inflammatory pathways. Mounting evidence suggests that HBOT may be effective for inflammatory bowel disease. Our systematic review and meta-analysis aimed to quantify the efficacy and safety of HBOT in fistulizing Crohn's disease (CD).

METHODS

A systematic review was conducted using the EMBASE, Web of Science, Pubmed, and Cochrane Library databases according to the "Preferred Reporting Items for Systematic Reviews and Meta-analyses" criteria. Study bias was assessed using the Cochrane Handbook guidelines.

RESULTS

Sixteen studies with 164 patients were included in the analysis. For all fistula subtypes, the pooled overall clinical response was 87% (95% CI: 0.70-0.95, I2 = 0) and the pooled clinical remission was 59% (95% CI: 0.35-0.80, I2 = 0). The overall clinical response was 89%, 84%, and 29% for perianal, enterocutaneous, and rectovaginal fistulas, respectively. On meta-regression, hours in the chamber and the number of HBOT sessions were not found to correlate with clinical response. The pooled number of adverse events was low at 51.7 per 10,000 HBOT sessions for all fistula types (95% CI: 16.8-159.3, I2 = 0). The risk of bias was observed across all studies.

CONCLUSION

HBOT is a safe and potentially effective treatment option for fistulizing CD. Randomized control trials are needed to substantiate the benefit of HBOT in fistulizing CD.

The Future of Advanced Therapies for Pediatric Crohn's Disease

Pediatric Crohn's disease commonly presents with moderate-to-severe intestinal inflammation with a greater risk of complications if remission is not achieved. Anti-tumor necrosis factor therapies have offered the possibility of deep and durable remission; however, many children do not respond or no longer respond over time. Further, some children do not require broader systemic immunosuppression to achieve remission and are better served by an alternative treatment strategy. Proper utilization of advanced biologic and small-molecule therapies, which have become available for adult patients since anti-tumor necrosis factor medications, is paramount for tighter disease control for a large proportion of children. Newer advanced therapies such as anti-integrin and anti-interleukin biologics, and several small-molecule agents capitalize on various mechanisms through narrower immunologic targets and reduced immunogenicity. Given limited regulatory approvals of these agents for use in children with Crohn's disease, clinicians continue to rely on data extrapolated from clinical trials in adult patients, sparse pediatric studies, and a growing real-world experience for treatment selection and optimization. In this article, we discuss currently available treatment options, pipeline drugs, and relevant data as they pertain to some of the most pressing clinical challenges faced in treating pediatric Crohn's disease.

Management of Perianal Crohn's Disease

Perianal Crohn's disease affects 25%-35% of patients with Crohn's disease and has proven to be one of the most difficult complications of the disease to treat. Patients with perianal Crohn's disease have lower health-related quality of life scores typically related to pain and fecal incontinence. In addition, patients with perianal Crohn's disease have higher rates of hospitalizations, surgeries, and overall healthcare costs. A multidisciplinary approach is necessary for the successful management of Crohn's disease with perianal fistula. Medical management is required to treat the underlying immune dysregulation to heal the luminal inflammation and the inflammation within the fistula tracts. Current options for medical therapy include biologics, dual therapy with thiopurines, therapeutic drug monitoring, and a close follow-up. Surgical management is critical to drain abscesses before immunosuppressive therapy and place setons when appropriate. Once the patient's inflammatory burden is well managed, definitive surgical therapies including fistulotomies, advancement flaps, and ligation of intersphincteric fistula tract procedures can be considered. Most recently, the use of stem cell therapy in the treatment of perianal fistula has given new hope to the cure of perianal fistula in Crohn's disease. This review will outline the most current data in the medical and surgical management of perianal Crohn's disease.

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.

Establishing a rabbit model of perianal fistulizing Crohn’s disease

BACKGROUND

Crohn's disease (CD) is a chronic nonspecific intestinal inflammatory disease. The aetiology and pathogenesis of CD are still unclear. Anal fistula is the main complication of CD and is a difficult problem to solve at present. The main limitation of developing new therapies is bound up with the short of preclinical security and effectiveness data. Therefore, an ideal animal model is needed to establish persistent anal fistula and an inflamed rectal mucosa.

AIM

To improve the induction method of colitis and establish a reliable and reproducible perianal fistulizing Crohn’s disease animal model to evaluate new treatment strategies.

METHODS

Twenty male New Zealand rabbits underwent rectal enema with different doses of 2,4,6-trinitrobenzene sulfonic acid to induce proctitis. Group A was treated with an improved equal interval small dose increasing method. The dosage of group B was constant. Seven days later, the rabbits underwent surgical creation of a transsphincteric fistula. Then, three rabbits were randomly selected from each group every 7 d to remove the seton from the fistula. The rabbits were examined by endoscopy every 7 days, and biopsy forceps were used to obtain tissue samples from the obvious colon lesions for histological analysis. The disease activity index (DAI), colonoscopy and histological scores were recorded. Perianal endoscopic ultrasonography (EUS) was used to evaluate the healing of fistulas.

RESULTS

Except for the DAI score, the colonoscopy and histological scores in group A were significantly higher than those in group B (P < 0.05). In the ideal model rabbit group, on the 7^th day after the removal of the seton, all animals had persistent lumens on EUS imaging, showing continuous full-thickness high signals. Histological inspection of the fistula showed acute and chronic inflammation, fibrosis, epithelialization and peripheral proctitis of the adjoining rectum.

CONCLUSION

The improved method of CD colitis induction successfully established a rabbit perianal fistula CD preclinical model, which was confirmed by endoscopy and pathology.

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 for the treatment of perianal fistulas in 20 patients with Crohn's disease: Results of the HOT-TOPIC trial after 1-year follow-up

Background

Previously published short‐term results (week 16) of this trial showed a significant improvement in clinical, radiologic and biochemical outcomes in Crohn's disease patients with therapy‐refractory perianal fistulas after treatment with hyperbaric oxygen therapy.

Objective

To assess the long‐term (week 60) efficacy, safety and feasibility of hyperbaric oxygen therapy in perianal fistula in Crohn's disease.

Methods

Crohn's disease patients with high perianal fistula(s) failing conventional treatment >6 months were included. Exclusion criteria were presence of a stoma, rectovaginal fistula(s) and recent changes in treatment regimens. Patients received 40 hyperbaric oxygen sessions and outcomes were assessed at week 16 and week 60.

Results

Twenty patients were included (median age 34 years). At week 16, median scores of the perianal disease activity index and modified Van Assche index (co‐primary outcomes) decreased from 7.5 (95% CI 6–9) to 4 (95% CI 3–6, p < 0.001) and 9.2 (95% CI 7.3–11.2) to 7.3 (95% CI 6.9–9.7, p = 0.004), respectively. At week 60, the respective scores remained significantly lower than baseline: 4 (95% CI 3–7, p < 0.001) and 7.7 (95% CI 5.2–10.2, p = 0.003). Perianal disease activity index score of 4 or less (representing inactive perianal disease) was observed in 13 patients at week 16 and 12 patients at week 60. Using fistula drainage assessment, 12 and 13 patients showed a clinical response at week 16 and 60, respectively, and clinical remission was achieved in four patients for both time points. At week 16, a statistically significant biochemical improvement (C‐reactive protein and faecal calprotectin levels) was found, but this effect was no longer significant at week 60.

Conclusions

The clinical and radiologic improvement of perianal fistula in Crohn's disease, that was found at week 16 after treatment with hyperbaric oxygen therapy, is maintained at 1‐year follow‐up.

Efficacy and tolerability of hyperbaric oxygen therapy in small bowel stricturing Crohn's disease: a pilot study

Background/Aims

Existing therapeutic options for complicated Crohn’s disease (CD) like biologics and surgery are limited by inadequate long-term efficacy, cost, and adverse effects. Tissue hypoxia is important in CD pathogenesis and may be ameliorated with hyperbaric oxygen therapy (HBOT). We assessed the efficacy and tolerability of HBOT in small bowel stricturing CD.

Methods

This pilot study included patients of small bowel stricturing CD (from April 2019 to January 2020) who underwent HBOT. These patients were refractory to conventional medical treatment or had multiple strictures not amenable to resection. Each session of HBOT was given for 60 minutes with a pressure of 1.5–2.5 atm. Clinical, biochemical responses and Short Inflammatory Bowel Disease (SIBD) questionnaire were evaluated at 2 and 6 months, and radiological response was evaluated at 6 months.

Results

Fourteen patients (mean age, 42.9±15.7 years; male, 50%) were subjected to 168 HBOT sessions. Thirteen patients (92.7%) had strictures and 1 patient had enterocutaneous fistula in addition. Median number of HBOT sessions was 11 (range, 3–20) which were administered over a median of 4 weeks. Most patients tolerated it well except 1 who had hemotympanum. At 2 and 6 months of follow-up, 64.2% of patients had a clinical response, 50% and 64.2% of patients had clinical remission respectively. Steroid-free clinical remission was seen in 8 (57%) of patients with radiological improvement in 50%. There was a significant improvement in SIBD scores at 2-month follow-up (59.4 vs. 44.5, P=0.03).

Conclusions

HBOT can be a safe and effective therapeutic option in patients with stricturing small bowel CD refractory to conventional medical treatment.

Managing complex perianal disease after anti-TNF failure: Where to go next?

Crohn's disease is a chronic inflammatory bowel disease that affects various intestinal segments and can involve the perianal region. Although anti-tumor necrosis factor (TNF) agents have revolutionized the management of Crohn's disease and improved the prognosis for patients with perianal Crohn's disease (pCD), their long-term effectiveness is limited: over 60% of patients relapse after one year of maintenance therapy. In recent years, significant advances have been made in the treatment of complex perianal fistulas after anti-TNF failure. Concomitant treatment with antibiotics and immunosuppressants improves the effectiveness of anti-TNF agents. Therapeutic drug monitoring and dose adjustment of anti-TNF therapy (targeting a higher trough level) might also improve treatment response. Novel therapeutic strategies might provide new opportunities for pCD management; for example, ustekinumab might be effective after anti-TNF treatment failure, although more studies are needed. As suggested in recent international guidelines, mesenchymal stem cell injection might be an effective, safe treatment for complex pCD.

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.

Journey through Crohn's Disease Complication: From Fistula Formation to Future Therapies

Crohn’s Disease (CD) is a chronic inflammatory disorder in which up to 50% of patients develop fistula within 20 years after the initial diagnosis, and half of these patients suffer perianal fistulizing disease. The etiopathogenesis of CD-related perianal fistula is still unclear, and its phenotypical and molecular characteristics are even more indefinite. A better understanding would be crucial to develop targeted and more effective therapeutic strategies. At present, the most accredited theory for the formation of CD-related fistula identifies the epithelial-to-mesenchymal transition (EMT) as the driving force. It has been well recognized that CD carries an increased risk of malignancy, particularly mucinous adenocarcinoma is often associated with long-standing fistula in CD patients. Despite the availability of multiple treatment options, perianal fistulizing CD represents a therapeutic challenge and is associated with an important impact on patients’ quality of life. To date, the most effective management is multidisciplinary with the cooperation of gastroenterologists, surgeons, radiologists, and nutritionists and the best recommended treatment is a combination of medical and surgical approaches.

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.

A Microsimulation Model to Project the 5-Year Impact of Using Hyperbaric Oxygen Therapy for Ulcerative Colitis Patients Hospitalized for Acute Flares

BACKGROUND

Hyperbaric oxygen therapy (HBOT) improves short-term outcomes for ulcerative colitis (UC) patients hospitalized for acute flares. Longer-term impacts and cost-effectiveness are unknown.

METHODS

We compared disease outcomes and cost-effectiveness of HBOT in addition to standard of care versus standard of care alone for UC patients hospitalized for acute flares using a microsimulation model. Published literature was used for transition probabilities, costs, and quality-adjusted life year (QALY) estimates. We modeled 100,000 individuals in each group over a 5-year horizon and compared rates of re-hospitalization, rescue medical therapy, colectomy, death, and cost-effectiveness at a willingness-to-pay of $100,000/QALY. Probabilistic sensitivity analyses were performed with 500 samples and 250 trials, in addition to multiple microsimulation sensitivity analyses.

RESULTS

The use of HBOT at the time of index hospitalization for an acute UC flare is projected to reduce the risk of re-hospitalization, inpatient rescue medical therapy, and inpatient emergent colectomy by over 60% (p < 0.001) and mortality by over 30% (p <0.001), during a 5-year horizon. The HBOT strategy costs more ($5600 incremental cost) but also yielded higher QALYs (0.13 incremental yield), resulting in this strategy being cost-effective ($43,000/QALY). Results were sensitive to HBOT costs and rates of endoscopic improvement with HBOT. Probabilistic sensitivity analyses observed HBOT to be more cost-effective than standard of care in 95% of iterations.

CONCLUSION

The use of HBOT to optimize response to steroids during the index hospitalization for an acute UC flare is cost-effective and is projected to result in significant reductions in disease-related complications in the long term.

ECCO Topical Review: Refractory Inflammatory Bowel Disease

Inflammatory bowel disease is a chronic disease with variable degrees of extent, severity, and activity. A proportion of patients will have disease that is refractory to licensed therapies, resulting in significant impairment in quality of life. The treatment of these patients involves a systematic approach by the entire multidisciplinary team, with particular consideration given to medical options including unlicensed therapies, surgical interventions, and dietetic and psychological support. The purpose of this review is to guide clinicians through this process and provide an accurate summary of the available evidence for different strategies.

Multidisciplinary management of perianal Crohn's disease

PURPOSE OF REVIEW

Multiple new medications with novel mechanisms of action are now available to treat Crohn's disease (CD). However, they have varying effectiveness in the management of perianal CD. Identifying the most appropriate therapy and optimizing it is essential to maximize effectiveness of therapy. Additionally, the management of perianal CD requires imaging of the perianal area to identify the fistula anatomy and local complications such as abscesses that require surgical drainage. Initial surgical assessment is key to drain abscesses and allow fistula healing with medical therapy.

RECENT FINDINGS

Although anti-tumor necrosis factor (TNFs) remain the most effective medications to treat perianal CD, real-world data suggests that ustekinumab may be a 2nd-line option in patients nonresponsive to an anti-TNF or having contraindications. Mesenchymal stem cells are an emerging therapeutic approach that is currently in Phase 3 trials in the United States and poised to play a major role in the treatment algorithm.

SUMMARY

The management of perianal CD requires a multidisciplinary approach with a combination of initial imaging and surgical assessment to adequately control local sepsis, optimization of biological therapy with adjunct antibiotics or immunomodulators, and close clinical follow-up with imaging to evaluate response to therapy and guide further surgical management options.

Efficacy and safety of hyperbaric oxygen therapy for moderate-to-severe ulcerative colitis: a protocol for a systematic review and meta-analysis

INTRODUCTION

Ulcerative colitis (UC) is a type of inflammatory bowel disease, and 62% of patients with UC felt that it is difficult for them to live a normal life. Furthermore, some researches have shown that about 15% of patients with UC undergo at least one extreme clinical course in their lifetime, and 10%-30% of patients with UC oblige colectomy. Although many investigations have demonstrated that HBO2 has a beneficial impact on UC treatment, a systematic review and meta-analysis are unavailable. Therefore, a meta-analysis is essential to assess the efficacy and safety of HBO2 in treating UC.

METHODS AND ANALYSIS

A systematic search plan will be performed in the following seven databases with a restriction of time from inception to September 2020 to filter the eligible studies: PubMed, Web of Science, Embase, Cochrane Library, China National Knowledge Infrastructure, Chinese Scientific Journal Database (VIP) and Chinese Biomedical Database WanFang. Other related resources will be also searched. Two independent reviewers will choose eligible researches and extract data. The risk of bias will be evaluated based on Cochrane Collaboration's Risk of Bias tool and Newcastle-Ottawa Scale. Eventually, a systematic review and meta-analysis will be performed via the Review Manager V.5.3 statistical software and STATA V.14.0 software.

ETHICS AND DISSEMINATION

This study will not involve the individual patient and any ethical problems since its outcomes are based on published data. Therefore, no ethical review and approval are required. We plan to publish the study in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42020210244.

Hyperbaric Oxygen Therapy in Chronic Inflammatory Conditions of the Pouch

BACKGROUND

Pouchitis can be a chronic complication of ileal pouch-anal anastomosis. We aimed to determine the efficacy and safety of hyperbaric oxygen therapy (HBOT) for chronic antibiotic-refractory pouchitis (CARP) and other inflammatory conditions of the pouch.

METHODS

This was a retrospective case series of adults with inflammatory bowel disease (IBD) who underwent ileal pouch-anal anastomosis and then developed CARP and received HBOT between January 2015 and October 2019. A modified Pouchitis Disease Activity Index (mPDAI) score was used to quantify subjective symptoms (0-6) and endoscopic findings (0-6) before and after HBOT.

RESULTS

A total of 46 patients were included, with 23 (50.0%) being males with a mean age of 43.6 ± 12.9 years. The median number of HBOT sessions was 30 (range 10-60). There was a significant reduction in the mean mPDAI symptom subscore from 3.19 to 1.91 after HBOT (P < 0.05). The pre- and post-HBOT mean mPDAI endoscopy subscores for the afferent limb were 2.31 ± 1.84 and 0.85 ± 1.28 (P = 0.006); for the pouch body, 2.34 ± 1.37 and 1.29 ± 1.38 (P < 0.001); and for the cuff, 1.93 ± 1.11 and 0.63 ± 1.12 (P < 0.001), respectively. Transient side effects included ear barotrauma in 5 patients (10.9%) and hyperbaric myopic vision changes in 5 patients (10.9%).

CONCLUSIONS

Despite minor adverse events, HBOT was well tolerated in patients with CARP and significantly improved symptoms and endoscopic parameters.

Hyperbaric Oxygen Therapy Is Effective in the Treatment of Inflammatory and Fistulizing Pouch Complications

Ileal pouch-anal anastomosis (IPAA) is the surgical treatment of choice for medically refractory ulcerative colitis. Pouch-related complications, such as pouchitis, cuffitis, or fistulae, occur in up to 50% of patients. Nearly 1 in 5 patients develop pouch-related complications refractory to medical therapy, including biologics. Hypoxia has been suggested as a trigger for these chronic refractory complications, and treating hypoxia may be of therapeutic benefit in this patient population. We investigated the effectiveness of hyperbaric oxygen therapy (HBOT) for patients with medically refractory pouch-related complications.

Hyperbaric oxygen therapy for the treatment of rectovaginal fistulas in patients with Crohn's disease: results of the HOT-REVA pilot study

Background

Positive effects of hyperbaric oxygen (HBO) on perianal fistulas in Crohn’s disease (CD) have been described, but the effect on rectovaginal fistulas (RVFs) has not yet been studied. The aim was to investigate the efficacy, safety and feasibility of HBO in patients with RVF in CD.

Methods

In this prospective study, consecutive CD patients between November 2018 and February 2020 presenting with RVF at the outpatient fistula clinic of the Amsterdam University Medical Centre were included and selected to receive treatment with 30 daily HBO sessions, if fistulas were actively draining and any concomitant treatment regimen was stable at least 6 weeks prior to start of HBO. Patients with a stoma were excluded. The primary endpoint was clinical closure at 3-month follow-up, defined as cessation of complaints and/or closure of the external orifice if visible at baseline. Secondary outcomes were improvement of concomitant perianal fistulas as measured by the perianal disease activity index (PDAI) and fistula drainage assessment (FDA), as well as improvement in patient-reported outcomes (visual analogue scale (VAS), inflammatory bowel disease questionnaire (IBDQ), faecal incontinence quality of life scale (FIQL) and female sexual functioning index (FSFI)) at 3-month follow-up.

Results

Out of 14 eligible patients, nine patients (median age 50 years) were treated, all of whom had previously had one or more unsuccessful medical and/or surgical treatments for their RVF. Clinical closure occurred in none of the patients at 3-month follow-up. There was no improvement in PDAI and patient-reported outcomes (VAS, IBDQ, FIQL and FSFI). Two patients had concomitant perianal fistulas; using FDA, one patient had a clinical response and one patient was in clinical remission 3 months after HBO. There were two treatment-related adverse events during HBO concerning claustrophobia and fatigue. Furthermore, two patients had a surgical intervention due to RVF and two patients were treated with antibiotics for a urinary tract infection during follow-up. One patient had a dose reduction of ustekinumab because of decreased luminal complaints.

Conclusion

Treatment with HBO was feasible, but in this therapy-refractory cohort without deviating ostomy no clinical closure of RVF or improvement in quality of life was seen 3 months after HBO. Treatment with HBO alone in this specific group of patients therefore appears to be ineffective.

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.

Hyperbaric oxygen therapy for the treatment of perianal fistulas in 20 patients with Crohn's disease

BACKGROUND

Positive effects of hyperbaric oxygen on perianal fistulas in Crohn's disease have been reported.

AIM

To assess efficacy, safety and feasibility of hyperbaric oxygen in Crohn's disease patients with therapy-refractory perianal fistulas.

METHODS

Twenty consecutive patients were recruited at the out-patient fistula clinic of the Amsterdam UMC. Crohn's disease patients with high perianal fistula(s) failing conventional treatment for over 6 months were included. Exclusion criteria were presence of a stoma, rectovaginal fistula(s) and recent changes in treatment regimens. Patients received treatment with 40 hyperbaric oxygen sessions and outcome parameters were assessed at Week 16.

RESULTS

Seven women and 13 men were included (median age 34 years). At Week 16, median scores of perianal disease activity index and modified van Assche index (co-primary outcome parameters) decreased from 7.5 (95% CI 6-9) to 4 (95% CI 3-6, P < 0.001), and from 9.2 (95% CI 7.3-11.2) to 7.3 (95% CI 6.9-9.7, P = 0.004) respectively. Perianal disease activity index scores ≤4 (representing inactive perianal disease) were observed in 13/20 patients (65%). Twelve patients showed a clinical response (60%) and four (20%) clinical remission, assessed with fistula drainage assessment. Median C-reactive protein and faecal calprotectin levels decreased from 4.2 mg/mL (95% CI 1.6-8) to 2.2 (95% CI 0.9-4.3, P = 0.003) and from 399 µg/g (95% CI 52-922) to 31 (95% CI 16-245, P = 0.001), respectively.

CONCLUSIONS

We found significant clinical, radiological and biochemical improvement in Crohn's disease patients with therapy-refractory perianal fistulas after treatment with hyperbaric oxygen.

CLINICAL TRIAL REGISTRATION

www.trialregister.nl/trial/6489.

Efficacy and safety evaluation of hyperbaric oxygen therapy for patients with ulcerative colitis: A protocol of systematic review and meta-analysis

BACKGROUND

Ulcerative colitis (UC) belongs to chronic colitis whose etiology and pathogenesis still have remained unclear. Hyperbaric oxygen therapy (HBOT) has been demonstrated to be effective for UC therapy. Still, evidence of its efficacy and safety is inconclusive. The purpose of the protocol is to evaluate the efficacy and safety of HBOT in UC therapy.

METHODS

This systematic review will retrieve studies that meet the requirements in Embase, MEDLINE, PubMed, Web of Science, Cochrane Library Central Register of Controlled Trials, the Chinese Biomedical Literature Database (CBM), China national knowledge infrastructure database (CNKI), Wei Pu database, Wan fang database, SinoMed, Google scholar, and Baidu Scholar from their inception to November 2020. Two authors are to be independent in their article selection, data collection, and research quality assessments. The primary outcome is the clinical effectiveness. And the secondary outcomes will include 4 criteria. RevMan 5.3 software will be utilized for analysis of the data.

RESULTS

The results of this study are to be submitted via a peer-reviewed journal.

CONCLUSIONS

The study is to assess the effectiveness and safety of HBOT for UC and provide valid and reliable evidence regarding HBOT for UC.

INPLASY REGISTRATION NUMBER

INPLASY2020100118.

The role of hyperbaric oxygen therapy in inflammatory bowel disease: a narrative review

Inflammatory bowel disease is a group of chronic recurrent diseases in the digestive tract, including ulcerative colitis and Crohn's disease. Over the past few decades, the treatment of IBD has made great progress but there is still a lot of room for improvement. Hyperbaric oxygen therapy (HBOT) was defined as the therapeutic effect of inhaling 100% oxygen higher than one atmosphere and reported to be used in stroke, decompression sickness and wound healing. Since several authors reported the role of HBOT as an adjunct to conventional medical treatment in patients with refractory IBD, the relevant research has shown an increasing trend in recent years. Clinical and experimental studies have revealed that HBOT may exert its therapeutic effect by inhibiting inflammation and strengthening the antioxidant system, promoting the differentiation of colonic stem cells and recruiting cells involved in repair. The purpose of this review is to summarize the past clinical and experimental studies and to understand the impact of HBOT in the treatment of IBD more deeply. In addition, we also hope to provide some ideas for future clinical and research work.

Modern surgical strategies for perianal Crohn's disease

One of the most challenging phenotypes of Crohn’s disease is perianal fistulizing disease (PFCD). It occurs in up to 50% of the patients who also have symptoms in other parts of the gastrointestinal tract, and in 5% of the cases it occurs as the first manifestation. It is associated with severe symptoms, such as pain, fecal incontinence, and a significant reduction in quality of life. The presence of perianal disease in conjunction with Crohn’s disease portends a significantly worse disease course. These patients require close monitoring to identify those at risk of worsening disease, suboptimal biological drug levels, and signs of developing neoplasm. The last 2 decades have seen significant advancements in the management of PFCD. More recently, newer biologics, cell-based therapies, and novel surgical techniques have been introduced in the hope of improved outcomes. However, in refractory cases, many patients face the decision of having a stoma made and/or a proctectomy performed. In this review, we describe modern surgical management and the most recent advances in the management of complex PFCD, which will likely impact clinical practice.

Hyperbaric Oxygen Therapy: Descriptive Review of the Technology and Current Application in Chronic Wounds

Hyperbaric oxygen therapy (HBOT) serves as "primary" or "adjunctive" therapy in a wide range of pathologies. It is considered the mainstay of management for potentially life-threatening conditions such as carbon monoxide poisoning, decompression illness, and gas embolisms. Moreover, HBOT has been utilized for decades as an adjunctive therapy in a variety of medical disciplines, including chronic wounds, which affect approximately 6.5 million Americans annually. In general, chronic wounds are characterized by hypoxia, impaired angiogenesis, and prolonged inflammation, all of which may theoretically be ameliorated by HBOT. Nonetheless, the cellular, biochemical, and physiological mechanisms by which HBOT achieves beneficial results in chronic wounds are not fully understood, and there remains significant skepticism regarding its efficacy. This review article provides a comprehensive overview of HBOT, and discusses its history, mechanisms of action, and its implications in management of chronic wounds. In particular, we discuss the current evidence regarding the use of HBOT in diabetic foot ulcers, while digging deeply into the roots of controversy surrounding its efficacy. We discuss how the paucity of high-quality research is a tremendous challenge, and offer future direction to address existing obstacles.

A phase 2B randomised trial of hyperbaric oxygen therapy for ulcerative colitis patients hospitalised for moderate to severe flares

BACKGROUND

Hyperbaric oxygen has been reported to improve disease activity in hospitalised ulcerative colitis (UC) patients.

AIM

To evaluate dosing strategies with hyperbaric oxygen for hospitalised UC patients.

METHODS

We enrolled UC patients hospitalised for acute flares (Mayo score 6-12). Initially, all patients received 3 days of hyperbaric oxygen at 2.4 atmospheres (90 minutes with two air breaks) in addition to intravenous steroids. Day 3 responders (reduction of partial Mayo score ≥ 2 points and rectal bleeding score ≥ 1 point) were randomised to receive a total of 5 days vs 3 days of hyperbaric oxygen.

RESULTS

We treated 20 patients with hyperbaric oxygen (75% prior biologic failure). Day 3 response was achieved in 55% (n = 11/20), with significant reductions in stool frequency, rectal bleeding and CRP (P < 0.01). A more significant reduction in disease activity was observed with 5 days vs 3 days of hyperbaric oxygen (P = 0.03). Infliximab or colectomy was required in only three patients (15%) despite a predicted probability of 80% for second-line therapy. Day 3 hyperbaric oxygen responders were less likely to require re-hospitalisation or colectomy by 3 months vs non-responders (0% vs 66%, P = 0.002). No treatment-related adverse events were observed.

CONCLUSION

Hyperbaric oxygen appears to be effective for optimising response to intravenous steroids in UC patients hospitalised for acute flares, with low rates of re-hospitalisation or colectomy at 3 months. An optimal clinical response is achieved with 5 days of hyperbaric oxygen. Larger phase 3 trials are needed to confirm efficacy and obtain labelled approval.

Development of an International, Multicenter, Hyperbaric Oxygen Treatment Registry and Research Consortium: Protocol for Outcome Data Collection and Analysis

BACKGROUND

Hyperbaric oxygen (HBO₂)-oxygen at pressures higher than atmospheric-is approved for 14 indications by the Undersea and Hyperbaric Medical Society. HBO₂'s main effect is to increase oxygen content in plasma and body tissues, which can counteract hypoxia or ischemia. Laboratory studies show that HBO₂ has effects beyond relieving hypoxia (eg, promoting angiogenesis in irradiated tissue, anti-inflammatory effects, radiosensitization of tumors, hypoxia preconditioning, and fungal growth inhibition) and has potential to treat conditions such as inflammatory bowel disease and pyoderma gangrenosum. Lack of consistently collected outcome data on a large cohort of individuals receiving HBO₂ therapy limits its use for both established and new indications. A course of therapy often involves 30-40 visits to a hyperbaric chamber, so the number of patients seen at any given center is constrained by chamber capacity. As a result, published HBO₂ outcome data tend to be from small case series because few patients with a particular condition are treated at a given center. To solve this problem, a registry that collects and pools data systematically from multiple institutions has been established.

OBJECTIVE

The aim of this study is to collect consistent outcome data across multiple hyperbaric centers to assess treatment effectiveness and establish a research consortium.

METHODS

A consortium of hyperbaric centers who have agreed to collect consistent outcome data on all patients seen has been assembled. Data are collected at each participating center using Research Electronic Data Capture (REDCap), a web-based, data collection system used frequently for research. Standard outcome measures have been defined for each condition, which are programmed into the REDCap data collection templates. Governance is through a consortium agreement that defines data security, data sharing, publications, liability, and other issues. Centers obtain Institutional Review Board (IRB) and ethics approval to participate, either from their own institutions or by relying on the IRB at the coordinating center at Dartmouth College. Dissemination will occur through a yearly report and by publications based on the data in the registry.

RESULTS

Early results from some common indications show significant pretreatment to posttreatment changes. Additional indications and outcome measures are being added using the procedures outlined in the consortium agreement.

CONCLUSIONS

The registry collects consistent outcome information for a therapy that needs further study and a stronger evidence base. It also overcomes the challenge of collecting data from an adequate number of patients for both established and emerging indications by combining data collection from multiple centers. The data entry requirements should be within the capabilities of existing staff at any given hyperbaric center. By using REDCap, the registry can be expanded to include detailed information on particular indications and long-term follow-up on selected patients without significantly increasing the basic data entry requirements. Through the registry, a network of enrolled hyperbaric centers has been established that provides the basis for a clinical trial network.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/18857.

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.

Effect of oxygen-producing suture material on hypoxic colonic anastomoses in an experimental model

Background

Anastomotic leak remains a significant cause of morbidity and mortality after colorectal surgery. Among multiple risk factors considered, hypoxia–ischaemia is considered to be a primary cause of intestinal anastomotic leakage. The aim of this experimental study was to assess safety, usability for surgical tasks, and efficacy of a newly developed oxygen‐producing suture material in the healing of colonic anastomoses under critical conditions.

Methods

An oxygen‐producing suture material was produced that is capable of releasing oxygen directly into the surrounding tissue. Off‐the‐shelf sutures loaded with calcium peroxide nano‐crystals and covered with poly(d,l‐lactide‐co‐glycolide) were assessed in vitro and in a rat model of hypoxic colonic anastomosis.

Results

In vitro assessment showed that these sutures can increase oxygen levels in a hypoxic environment. Potential oxygen byproducts did not seem to have a negative impact on the viability of intestinal cells. The use of oxygen‐producing sutures in vivo resulted in increased tissue oxygen saturation, measured by visible light spectroscopy, and increased mechanical stability of the anastomosis.

Conclusion

Oxygen‐producing suture material increased tissue oxygen saturation and mechanical stability of colonic anastomosis in a rat model.

Management of Complex Anorectal and Perianal Crohn's Disease

Perianal symptoms occur in up to 50% of patients with Crohn's disease in other parts of the gastrointestinal tract, and in 5% of patients it is the first manifestation of the disease. The perianal area is often under stress in patients with Crohn's disease, because of the diarrhea, and the fecal urgency, frequency, and incontinence caused by proximal disease. Symptomatic perianal disease can therefore be due to the effects of the stress on an otherwise normal anus, or the result of Crohn's disease in the low rectum and/or perianal tissues themselves. This key distinction should drive the investigation and management of anal and perianal symptoms in patients with Crohn's disease. In this review, the evaluation and management of the various manifestations of Crohn's disease in the perineum and perianal tissues will be described.

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.

Contemporary Medical Management of Acute Severe Ulcerative Colitis

Acute severe ulcerative colitis is a medical emergency that requires prompt recognition, evaluation, and intervention. Patients require hospital admission with laboratory, radiographic, and endoscopic evaluation with initiation of corticosteroid treatment. Despite early intervention, many patients require salvage medical therapy, with some progressing to colectomy. Here we review important concepts and recent advances in the evaluation and medical management of adult and pediatric patients with acute severe ulcerative colitis.

Pharmacological Approach to the Management of Crohn's Disease Patients with Perianal Disease

Perianal localization of Crohn's disease involves significant morbidity, affects quality of life and results in an increased use of healthcare resources. Medical and surgical therapies contribute to its management. The objective of this review is to address the current understanding in the management of perianal Crohn's disease, with the main focus in reviewing pharmacological therapies, including stem cells. In complex fistulas, once local sepsis has been controlled by surgical drainage and/or antibiotics, anti-TNF drugs (infliximab, adalimumab) are the first-line therapy, with or without associated immunomodulators. Combining surgery and anti-TNF therapy has additional benefits for healing. However, response is inadequate in up to half of cases. A possible role of new biological drugs in this context (vedolizumab, ustekinumab) is an area of ongoing investigation, as is the local application of autologous or allogeneic mesenchymal stem cells. These are non-hematopoietic multipotent cells with anti-inflammatory and immunomodulatory properties, the use of which may successfully treat refractory patients, and seem to be a promising and safe alternative to achieving fistula healing in Crohn's disease, without known systemic effects.

Hyperbaric oxygen therapy is well tolerated and effective for ulcerative colitis patients hospitalized for moderate-severe flares: a phase 2A pilot multi-center, randomized, double-blind, sham-controlled trial

BACKGROUND

Hyperbaric oxygen therapy (HBOT) markedly increases tissue oxygen delivery. Case series suggest it may have a potential therapeutic benefit in ulcerative colitis (UC). We investigated the therapeutic potential of HBOT as an adjunct to steroids for UC flares requiring hospitalization.

METHODS

The study was terminated early due to poor recruitment with 18 of the planned 70 patients enrolled. UC patients hospitalized for moderate-severe flares (Mayo score ≥6, endoscopic sub-score ≥2) were block randomized to steroids + daily HBOT (n = 10) or steroids + daily sham hyperbaric air (n = 8). Patients were blinded to study assignment, and assessments were performed by a blinded gastroenterologist. Primary outcome was the clinical remission rate at study day 5 (partial Mayo score ≤2 with no sub-score >1). Key secondary outcomes were: clinical response (reduction in partial Mayo score ≥2, rectal bleeding sub-score of 0-1) and progression to second-line therapy (colectomy or biologic therapy) during the hospitalization.

RESULTS

A significantly higher proportion of HBOT-treated patients achieved clinical remission at study day 5 and 10 (50 vs. 0%, p = 0.04). HBOT-treated patients less often required progression to second-line therapy during the hospitalization (10 vs. 63%, p = 0.04). The proportion requiring in-hospital colectomy specifically as second-line therapy for medically refractory UC was lower in the HBOT group compared to sham (0 vs. 38%, p = 0.07). There were no serious adverse events.

CONCLUSION

In this small, proof-of-concept, phase 2A trial, the use of HBOT as an adjunctive therapy to steroids for UC patients hospitalized for moderate-severe flares resulted in higher rates of clinical remission, and a reduction in rates of progression to second-line therapy during the hospitalization. Larger well-powered trials are needed, however, to provided definitive evidence of therapeutic benefit.

Hyperbaric Oxygen for Hospitalized patients with Ulcerative Colitis

One quarter of patients with ulcerative colitis will develop a severe acute exacerbation of disease during their lifetime. Despite high dose corticosteroids, half of these patients will fail subsequent medical rescue therapy, and half will require colectomy within 5 years. Dulai and colleagues report the results of a fascinating, double blind, sham controlled, proof of concept trial which demonstrated that administration of short term hyperbaric oxygen therapy (HBOT) at the point of presentation with severe UC was able to rapidly induce short term remission and avoid the need for urgent second line medical rescue therapy. Further dose finding studies are underway.

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.

Mechanisms of action involved in ozone-therapy in skin diseases

Ozone-therapy initially applied in medicine by an empirical approach, has now reached a new stage where most of the biological mechanisms of ozone action have been clarified, that refers to antimicrobial effects, immunoregulation, antioxidant defenses and epigenetic modification. Current ozone medical preparation in dermatology mainly classified as ozone hydrotherapy, ozonated oil externally used and ozone autohemotherapy (OAHT). Admittedly, ozone is widely used in various fields against gram-negative and gram-positive bacteria, viruses, and fungi. More recently, great progress has been obtained in wound healing which is a multiphase process that consists of three overlapping but distinct stages: inflammation, tissue proliferation and remodeling. While the exact mechanisms of ozone-therapy still remain unclear. Therefore, more evidence is required before ozone can be presented as a promising method for the management and prevention of various skin diseases. In this review, we review the application status of ozone in dermatology and summarize possible mechanisms of ozone-therapy on skin diseases, aims to shed a light on providing a series of theoretical basis for its applications.

Environmental triggers in IBD: a review of progress and evidence

A number of environmental factors have been associated with the development of IBD. Alteration of the gut microbiota, or dysbiosis, is closely linked to initiation or progression of IBD, but whether dysbiosis is a primary or secondary event is unclear. Nevertheless, early-life events such as birth, breastfeeding and exposure to antibiotics, as well as later childhood events, are considered potential risk factors for IBD. Air pollution, a consequence of the progressive contamination of the environment by countless compounds, is another factor associated with IBD, as particulate matter or other components can alter the host's mucosal defences and trigger immune responses. Hypoxia associated with high altitude is also a factor under investigation as a potential new trigger of IBD flares. A key issue is how to translate environmental factors into mechanisms of IBD, and systems biology is increasingly recognized as a strategic tool to unravel the molecular alterations leading to IBD. Environmental factors add a substantial level of complexity to the understanding of IBD pathogenesis but also promote the fundamental notion that complex diseases such as IBD require complex therapies that go well beyond the current single-agent treatment approach. This Review describes the current conceptualization, evidence, progress and direction surrounding the association of environmental factors with IBD.

Treatment of perianal Crohn's disease

Perianal Crohn's is a common manifestation of Crohn's disease. Primary manifestations of perianal disease mirror common anorectal conditions, however treatment is less successful than in those patients without Crohn's related perianal disease. A multimodal approach to therapy including medical and surgical modalities is often necessary. The goal of treatment is to manage symptoms while maintaining continence.

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.

Management of complex perianal Crohn's disease

Patients with Crohn's disease often develop perianal disease, successfully managed in most cases. However, its most aggressive form, complex perianal disease, is associated with high morbidity and a significant impairment in patients' quality of life. The aim of this review is to provide an updated approach to this condition, reviewing aspects of its epidemiology, diagnosis and therapeutic alternatives. Emerging treatment options are also discussed. A multidisciplinary assessment of these patients with a coordinated medical and surgical approach is crucial.

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.

Effects of adenosine metabolism in astrocytes on central nervous system oxygen toxicity

Hyperbaric oxygen (HBO) is widely used in military operations, especially underwater missions. However, prolonged and continuous inhalation of HBO can cause central nervous system oxygen toxicity (CNS-OT), which greatly limits HBO's application. The regulation of astrocytes to the metabolism of adenosine is involved in epilepsy. In our study, we aimed to observe the effects of HBO exposure on the metabolism of adenosine in the brain. Furthermore, we aimed to confirm the possible mechanism underlying adenosine's mediation of the CNS-OT. Firstly, anesthetized rats exposed to 5 atm absolute HBO for 80 min. The concentrations of extracellular adenosine, ATP, ADP, and AMP were detected. Secondly, free-moving rats were exposed to HBO at the same pressure for 20 min, and the activities of 5'-nucleotidase and ADK in brain tissues were measured. For the mechanism studies, we observed the effects of a series of different doses of drugs related to adenosine metabolism on the latency of CNS-OT. Results showed HBO exposure could increase adenosine content by inhibiting ADK activity and improving 5'-nucleotidase activity. And adenosine metabolism during HBO exposure may be a protective response against HBO-induced CNS-OT. Moreover, the improvement of adenosine concentration, activation of adenosine A1R, or suppression of ADK and adenosine A2AR, which are involved in the prevention of HBO-induced CNS-OT. This is the first study to demonstrate HBO exposure regulated adenosine metabolism in the brain. Adenosine metabolism and adenosine receptors are related to HBO-induced CNS-OT development. These results will provide new potential targets for the termination or the attenuation of CNS-OT.