Systematic review of hyperbaric oxygen therapy for the treatment of radiation-induced skin necrosis

Is there a rationale for hyperbaric oxygen therapy in the patients with Post COVID syndrome? : A critical review

The SARS-CoV-2 pandemic has resulted in 762 million infections worldwide from 2020 to date, of which approximately ten percent are suffering from the effects after infection in 2019 (COVID-19) [1, 40]. In Germany, it is now assumed that at least one million people suffer from post-COVID condition with long-term consequences. These have been previously reported in diseases like Myalgic Encephalomyelitis (ME) and Chronic Fatigue Syndrome (CFS). Symptoms show a changing variability and recent surveys in the COVID context indicate that 10-30 % of outpatients, 50 to 70% of hospitalised patients suffer from sequelae. Recent data suggest that only 13% of all ill people were completely free of symptoms after recovery [3, 9]. Current hypotheses consider chronic inflammation, mitochondrial dysfunction, latent viral persistence, autoimmunity, changes of the human microbiome or multilocular sequelae in various organ system after infection. Hyperbaric oxygen therapy (HBOT) is applied since 1957 for heart surgery, scuba dive accidents, CO intoxication, air embolisms and infections with anaerobic pathogens. Under hyperbaric pressure, oxygen is physically dissolved in the blood in higher concentrations and reaches levels four times higher than under normobaric oxygen application. Moreover, the alternation of hyperoxia and normoxia induces a variety of processes at the cellular level, which improves oxygen supply in areas of locoregional hypoxia. Numerous target gene effects on new vessel formation, anti-inflammatory and anti-oedematous effects have been demonstrated [74]. The provision of intermittently high, local oxygen concentrations increases repair and regeneration processes and normalises the predominance of hyperinflammation. At present time only one prospective, randomized and placebo-controlled study exists with positive effects on global cognitive function, attention and executive function, psychiatric symptoms and pain interference. In conclusion, up to this date HBO is the only scientifically proven treatment in a prospective randomized controlled trial to be effective for cognitive improvement, regeneration of brain network and improvement of cardiac function. HBOT may have not only theoretical but also potential impact on targets of current pathophysiology of Post COVID condition, which warrants further scientific studies in patients.

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

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

Implications of Malignancy, Radiation, and Timing of Major Nasal Reconstruction

Owing to the complex, multilayered anatomy of the nose in the central face, major nasal reconstruction can pose a significant challenge for reconstructive surgeons. It is the responsibility of reconstructive surgeons to have an understanding of the most common cutaneous malignancies and excisional techniques that may lead to complex nasal defects. The purpose of this article is to discuss these malignancies, excisional techniques, and impacts of radiation on tissue that has implications for reconstructive surgeons.

Hyperbaric oxygen therapy for late radiation tissue injury

BACKGROUND

This is the third update of the original Cochrane Review published in July 2005 and updated previously in 2012 and 2016. Cancer is a significant global health issue. Radiotherapy is a treatment modality for many malignancies, and about 50% of people having radiotherapy will be long-term survivors. Some will experience late radiation tissue injury (LRTI), developing months or years following radiotherapy. Hyperbaric oxygen therapy (HBOT) has been suggested as a treatment for LRTI based on the ability to improve the blood supply to these tissues. It is postulated that HBOT may result in both healing of tissues and the prevention of complications following surgery and radiotherapy.

OBJECTIVES

To evaluate the benefits and harms of hyperbaric oxygen therapy (HBOT) for treating or preventing late radiation tissue injury (LRTI) compared to regimens that excluded HBOT.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 24 January 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing the effect of HBOT versus no HBOT on LRTI prevention or healing.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. survival from time of randomisation to death from any cause; 2. complete or substantial resolution of clinical problem; 3. site-specific outcomes; and 4.

ADVERSE EVENTS

Our secondary outcomes were 5. resolution of pain; 6. improvement in quality of life, function, or both; and 7. site-specific outcomes. We used GRADE to assess certainty of evidence.

MAIN RESULTS

Eighteen studies contributed to this review (1071 participants) with publications ranging from 1985 to 2022. We added four new studies to this updated review and evidence for the treatment of radiation proctitis, radiation cystitis, and the prevention and treatment of osteoradionecrosis (ORN). HBOT may not prevent death at one year (risk ratio (RR) 0.93, 95% confidence interval (CI) 0.47 to 1.83; I2 = 0%; 3 RCTs, 166 participants; low-certainty evidence). There is some evidence that HBOT may result in complete resolution or provide significant improvement of LRTI (RR 1.39, 95% CI 1.02 to 1.89; I2 = 64%; 5 RCTs, 468 participants; low-certainty evidence) and HBOT may result in a large reduction in wound dehiscence following head and neck soft tissue surgery (RR 0.24, 95% CI 0.06 to 0.94; I2 = 70%; 2 RCTs, 264 participants; low-certainty evidence). In addition, pain scores in ORN improve slightly after HBOT at 12 months (mean difference (MD) -10.72, 95% CI -18.97 to -2.47; I2 = 40%; 2 RCTs, 157 participants; moderate-certainty evidence). Regarding adverse events, HBOT results in a higher risk of a reduction in visual acuity (RR 4.03, 95% CI 1.65 to 9.84; 5 RCTs, 438 participants; high-certainty evidence). There was a risk of ear barotrauma in people receiving HBOT when no sham pressurisation was used for the control group (RR 9.08, 95% CI 2.21 to 37.26; I2 = 0%; 4 RCTs, 357 participants; high-certainty evidence), but no such increase when a sham pressurisation was employed (RR 1.07, 95% CI 0.52 to 2.21; I2 = 74%; 2 RCTs, 158 participants; high-certainty evidence).

AUTHORS' CONCLUSIONS

These small studies suggest that for people with LRTI affecting tissues of the head, neck, bladder and rectum, HBOT may be associated with improved outcomes (low- to moderate-certainty evidence). HBOT may also result in a reduced risk of wound dehiscence and a modest reduction in pain following head and neck irradiation. However, HBOT is unlikely to influence the risk of death in the short term. HBOT also carries a risk of adverse events, including an increased risk of a reduction in visual acuity (usually temporary) and of ear barotrauma on compression. Hence, the application of HBOT to selected participants may be justified. The small number of studies and participants, and the methodological and reporting inadequacies of some of the primary studies included in this review demand a cautious interpretation. More information is required on the subset of disease severity and tissue type affected that is most likely to benefit from this therapy, the time for which we can expect any benefits to persist and the most appropriate oxygen dose. Further research is required to establish the optimum participant selection and timing of any therapy. An economic evaluation should also be undertaken.

Complications after Prostate Cancer Treatment: Pathophysiology and Repair of Post-Radiation Urethral Stricture Disease

Radiation therapy (RT) in the management of pelvic cancers remains a clinical challenge to urologists given the sequelae of urethral stricture disease secondary to fibrosis and vascular insults. The objective of this review is to understand the physiology of radiation-induced stricture disease and to educate urologists in clinical practice regarding future prospective options clinicians have to deal with this condition. The management of post-radiation urethral stricture consists of conservative, endoscopic, and primary reconstructive options. Endoscopic approaches remain an option, but with limited long-term success. Despite concerns with graft take, reconstructive options such as urethroplasties in this population with buccal grafts have shown long-term success rates ranging from 70 to 100%. Robotic reconstruction is augmenting previous options with faster recovery times. Radiation-induced stricture disease is challenging with multiple interventions available, but with successful outcomes demonstrated in various cohorts including urethroplasties with buccal grafts and robotic reconstruction.

Effects of an early intervention with Hyperbaric Oxygen Treatment on arm lymphedema and quality of life after breast cancer-an explorative clinical trial

PURPOSE

Lymphedema (LE) is a common complication after breast cancer treatment, which negatively affects the quality of life (QOL). Hyperbaric Oxygen Treatment (HBOT) is an established treatment for radiation-induced tissue injury, but evidence of effect on breast cancer-related LE is inconclusive. We aimed to explore effects of HBOT on early breast cancer-related LE and the implications for QOL.

METHODS

We invited women with breast cancer treated with surgery, axillary dissection and radiotherapy, who had participated in a randomized controlled trial and who presented with LE 1 year after surgery. In a prospective observational study design, change in LE was assessed with perometry, dual-energy X-ray absorptiometry (DXA) and lymphoscintigraphy, and QOL by validated self-report scales. Participants were offered 40 sessions of HBOT on every weekday for 8 weeks and were followed for 6 months.

RESULTS

Out of 50 eligible participants, 20 women accepted participation. Nineteen women initiated and completed treatment and follow-up. None of the objective measures of LE severity showed consistent changes during the study period, but participants reported significant improvements in QOL (physical functioning, fatigue, insomnia and breast and arm symptoms), with improvements peaking at 6-month follow-up.

CONCLUSION

Participants receiving HBOT experienced improved QOL without consistently significant changes in arm mass, volume or lymphatic drainage. These results call for studies into differential effect in patient sub-groups, and a large-scale, randomized placebo-controlled trial with long-term follow-up to assess the effect of HBOT in patients with soft tissue radiation injuries after breast cancer seems warranted.

TRIAL REGISTRATION

Danish Health and Medicines Authority, EUDRACT no. 2015-000,604-25 Ethical committee of the Capitol Region, No. R96-A6604-14-S22.

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

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

Superior gluteal artery perforator flap salvaged via hyperbaric oxygen therapy

The superior gluteal artery perforator (SGAP) flap can be challenging and in common with all flaps can develop venous and arterial insufficiency. Several prior studies have demonstrated the successful utility of hyperbaric oxygen therapy (HBOT) in the salvage of compromised flaps, mainly with deep inferior epigastric perforator, latissimus dorsi or transverse rectus abdominis myocutaneous flaps. SGAP flaps are autologous alternatives to abdominal-based flaps and provides adequate adipose tissue for breast reconstruction. We report a case of a woman in her 50s who underwent a delayed bilateral breast reconstruction using SGAP free flaps. Postoperatively, venous congestion of her right breast flap was noted for which she was referred for HBOT. An acceptable aesthetic result was achieved following 17 HBOT treatments. This is the first case we can find in the published literature of ischaemic SGAP free flap being salvaged by HBOT.

Treatment of a Chronic Vulvar Wound by Hyperbaric Oxygen Therapy (HBOT)

We hereby report the case of a 66-year-old obese patient (BMI 30) with type 2 diabetes, who presented a chronic vulvar lesion on the left labia majora following surgical drainage of an abscess. After multiple unsuccessful treatments by antibiotics and local wound care, we proposed a trial of hyperbaric oxygen therapy (HBOT). The patient fully recovered after 54 sessions at 2.5 ATA, 95 minutes each. HBOT has been studied for perineal lesion such as skin atrophy or necrosis caused by irradiation but not for vulvar nonhealing chronic lesions in the case of impaired vascularization caused by diabetes. This case is, to our knowledge, one of the first publications about the healing boost of HBOT in chronic vulvar wounds due to vascular impairment.

The EANM guideline for radiosynoviorthesis

PURPOSE

Radiosynoviorthesis (RSO) using the intraarticular application of beta-particle emitting radiocolloids has for decades been used for the local treatment of inflammatory joint diseases. The injected radiopharmaceuticals are phagocytized by the superficial macrophages of the synovial membrane, resulting in sclerosis and fibrosis of the formerly inflamed tissue, finally leading to reduced joint effusion and alleviation of joint pain.

METHODS

The European Association of Nuclear Medicine (EANM) has written and approved these guidelines in tight collaboration with an international team of clinical experts, including rheumatologists. Besides clinical and procedural aspects, different national legislative issues, dosimetric considerations, possible complications, and side effects are addressed.

CONCLUSION

These guidelines will assist nuclear medicine physicians in performing radiosynoviorthesis. Since there are differences regarding the radiopharmaceuticals approved for RSO and the official indications between several European countries, this guideline can only give a framework that must be adopted individually.

Treatment of Soft-Tissue Necrosis of the Pyriform Sinus Using Pentoxyllifylline and Tocopherol

Radiotherapy of the head and neck can often lead to complications and side effects, including osteoradionecrosis and soft tissue necrosis. One relatively well-established method of treating osteoradionecrosis includes the PENTOCLO protocol, which consists of Pentoxyllifylline, Tocopherol, and Clodronate. Despite its success in the treatment of osteoradionecrosis, the effectiveness of components of the PENTOCLO protocol in treating soft tissue necrosis of the head and neck is underexplored. This case study reviews the successful treatment of a pyriform sinus ulcer that developed after the use of radiotherapy in treating a T3N2b squamous cell carcinoma. The treatment plan used Pentoxyllifylline and Tocopherol, and omitted Clodronate, and can therefore be referred to as a PENTO protocol.

Effect of Team Health Education on Radiodermatitis in Patients with Head and Neck Tumor Radiotherapy Under the Joint Committee International Standards

OBJECTIVES

This study aimed to investigate the impacts of team health education on radiodermatitis in patients undergoing head and neck radiotherapy.

DATA SOURCES

A total of 118 patients undergoing radiotherapy at the Oncology Department of Qingdao Municipal Hospital under the Joint Committee International (JCI) accreditation standards of medical and health institutions were divided into two groups according to the order of the admission: the intervention group (n = 66) and the control group (n = 52). The patients in the control group were given routine nursing, while those in the intervention group received team health education based on the control group. The incidence and satisfaction of radiodermatitis were observed and compared between the groups, and the EORTC QLQ-C30 and General Quality of Life Inventory-74 were used to evaluate the patients' quality of life when after radiotherapy and when after 6 months post the radiotherapy, respectively.

CONCLUSION

The incidence of radiodermatitis was 100% in both groups, and the difference in the grade of radiodermatitis and quality of life was significant (P < .05) between them.

IMPLICATIONS FOR NURSING PRACTICE

Team health education under the JCI standards team can reduce the degree of skin injury due to radiodermatitis and improve the quality of life.

Radiotherapy for prevention or management of gynecomastia recurrence: Future role for general gynecomastia patients in plastic surgery given current role in management of high-risk prostate cancer patients on anti-androgenic therapy

PURPOSE

Several technologies and innovative approaches continue to emerge for the optimal management of gynecomastia by plastic surgeons; the present study investigates the role of radiation therapy in this context.

METHODS

A systematic review was performed to evaluate the utility of radiotherapy for the prevention and treatment of gynecomastia incidence or recurrence by plastic surgeons.

RESULTS

Fifteen articles met the inclusion criteria for review. The mean incidence of gynecomastia was 70% in the high-risk population examined representing prostate cancer patients on estrogen or anti-androgen therapy. Radiotherapy was shown to significantly reduce the incidence to a median of 23%, with all six randomized control studies assessed demonstrating a statistically significant decrease in incidence following radiotherapy prophylaxis. Doses examined ranged from 8 to 16 Gy, delivered between 1 and 11 fractions. Complications following radiotherapy were minor and self-limiting in all cases, restricted to minor skin reactions, and associated with larger radiotherapy doses delivered in fewer fractions. The median complication rate was 12.4% with no major complications, such as neoplastic, pulmonary, or adverse cardiac outcomes. While the efficacy of radiation therapy as a treatment modality for gynecomastia was also established, it was shown to be less effective than other available options.

CONCLUSIONS

Low-dose radiotherapy to the male breast might be a safe and effective strategy to prevent gynecomastia incidence or recurrence in high-risk patients; further studies are indicated within the common gynecomastia population managed by plastic surgeons to assess the clinical and economical utility of this intervention before a recommendation for its ubiquitous adoption in plastic surgery can be made to continue improving outcomes for high-risk gynecomastia patients.

Influence of hyperbaric oxygen therapy on bone metabolism in patients with neoplasm

Background

Hyperbaric oxygen therapy (HBOT) is useful in the treatment of complications due to radiotherapy in patients with neoplasm. Its effects on bone metabolism are unclear. In our study, we analyzed the effects of HBOT on bone remodeling in oncological patients with radiotherapy.

Materials and methods

Prospective clinical study in 23 patients with neoplasms undergoing treatment with HBOT due to complications of radiotherapy (hemorrhagic cystitis, proctitis or radionecrosis) and 25 patients with chronic anal fissure. The average number of HBOT sessions was 20 ± 5 (100% oxygen, 2.3 atmospheres and 90 min per day). Serum levels of aminoterminal propeptide of type I collagen (P1NP), C terminal telopeptide of type I collagen (CTX), alkaline phosphatase (AP), 25hydroxyvitamin D (25-OHD), parathyroid hormone (PTH), were measured at 3 time points: T0 (before beginning HBOT), T1 (at the end of HBOT) and T2 (6 months after HBOT).

Results

At baseline, the patients with neoplasm have higher bone turnover than those with anal fissure. These differences were 41% in CTX (0.238 ± 0.202 ng/mL in neoplasm and 0.141 ± 0.116 ng/mL in fissure; p = 0.04), 30% for PTH (46 ± 36 pg/mL in neoplasm and 32 ± 17 pg/mL in fissure; p = 0.04) and 15% for alkaline phosphatase (80 ± 24 U/L in neoplasm and 68 ± 16 U/L in fissure; p = 0.04). In the group with neoplasm, the values of P1NP decreased 6% after HBOT (T0: 49 ± 31 ng/mL, T2: 46 ± 12 ng/mL; p = 0.03). Also, there were non-significant decreases in PTH (-34%) and CTX (-30%).

Conclusions

Patients with neoplasm and complications with radiotherapy have an increase in bone remodeling that may be diminished after HBOT.

Combination of Extended Paramedian Forehead Flap and Laser Hair Removal in the Reconstruction of Distal Nasal Defect

AIM

The study sought to determine whether extended forehead flap by using part of the scalp combined with laser hair removal is a practical approach when repairing distal nasal defect.

METHODS

A retrospective study was conducted with 6 patients who underwent reconstruction of nasal defects with extended forehead flaps (including scalp combined with subsequent laser hair removal) at Shanghai Ninth People's Hospital between June 2016 and December 2018. Surgical data collected included age, causes of defects, sizes of defects, invaded nasal subunits, implantation of tissue expander, time elapsed between the formation of defects and surgical treatments, sessions of laser hair removal, and follow-up results. All patients had nasal defects after removal of a benign nevus (diameter, >1.5 cm), which invaded distal nasal subunits (including the nasal tip, soft triangle, columella, and nasal ala) and could not be repaired using adjacent tissue. Preoperative and postoperative assessments of esthetic outcomes were analyzed, including skin color and texture match, appearance deformity, and scar appearance.

RESULTS

All 6 female patients (ages 4 to 24 years) accepted the extended forehead flap technique and subsequent laser hair removal treatments. Among the 6 patients, 2 had nasal tip defects, 1 had a columella nasi defect, one had an alar defect, and 2 had multiunit defects. All transferred forehead flaps survived with no necrosis and underwent 2 to 5 subsequent laser hair removal treatments. The color and texture of the transferred flaps was similar to the adjacent skin in all patients. All patients were satisfied with the final outcome of the reconstructed nose with no obvious scarring during follow-up.

CONCLUSIONS

Extending the forehead flap using the scalp is a practical and safe approach for the repair of large and distal nasal defects. Subsequent laser hair removal can eliminate the hair follicles of the scalp and improve the appearance and color of the flap.

The "Double hit": Free tissue transfer is optimal in comorbid population with irradiated wounds for successful limb salvage

BACKGROUND

Radiation therapy causes histopathologic changes in tissues, including fibrosis, loss of tissue planes, and vascular damage, which can lead to chronic wound formation. Patients with nonhealing, irradiated wounds and comorbidities that affect microvasculature suffer a "double hit", which leads to delayed wound healing. Local wound care and grafts are commonly insufficient. In this study, we evaluated limb salvage outcomes and long-term complications after free tissue transfer (FTT) in patients with chronic, irradiated leg wounds.

METHODS

We retrospectively reviewed patients with irradiated lower extremity wounds who underwent FTT from 2012 to 2017. Primary outcomes included limb salvage, ambulation, and overall flap success. Reconstruction involved complete excision of irradiated tissue and coverage with well-vascularized tissue.

RESULTS

Seven free flaps in six patients were identified. Average age was 68.4 years and average BMI was 27.8 kg/m². Comorbid conditions included hypertension (57.1%), peripheral vascular disease (57.1%), underlying hypercoagulability (42.9%), diabetes (14.3%), and tobacco use (14.3%). Wounds were present for an average of 25.5 months prior to FTT. Donor sites included anterolateral thigh (71.4%), vastus lateralis (14.3%), and latissimus dorsi (14.3%). Overall flap success rate was 100% with one patient requiring reoperation for dehiscence. Limb salvage rate was 85.7% with one patient undergoing elective amputation due to pain. All patients could ambulate (one used a prosthesis) at a mean follow-up time of 1.4 years.

CONCLUSIONS

Radiation therapy in a comorbid population often leads to the formation of chronic nonhealing wounds. We advocate for earlier consideration of FTT to provide healthy vascularized tissues, thereby avoiding prolonged wound care and patient burden. Successful limb salvage outcomes can be achieved.

An Extra Breath of Fresh Air: Hyperbaric Oxygenation as a Stroke Therapeutic

Stroke serves as a life-threatening disease and continues to face many challenges in the development of safe and effective therapeutic options. The use of hyperbaric oxygen therapy (HBOT) demonstrates pre-clinical effectiveness for the treatment of acute ischemic stroke and reports reductions in oxidative stress, inflammation, and neural apoptosis. These pathophysiological benefits contribute to improved functional recovery. Current pre-clinical and clinical studies are testing the applications of HBOT for stroke neuroprotection, including its use as a preconditioning regimen. Mild oxidative stress may be able to prime the brain to tolerate full extensive oxidative stress that occurs during a stroke, and HBOT preconditioning has displayed efficacy in establishing such ischemic tolerance. In this review, evidence on the use of HBOT following an ischemic stroke is examined, and the potential for HBOT preconditioning as a neuroprotective strategy. Additionally, HBOT as a stem cell preconditioning is also discussed as a promising strategy, thus maximizing the use of HBOT for ischemic stroke.

Repeated exposure to hyperbaric hyperoxia affects mitochondrial functions of the lung fibroblasts

Hyperbaric oxygen (HBO) therapy, i.e. breathing pure oxygen under increased environmental pressures serves as a treatment for diverse medical conditions. However, elevated oxygen concentration can be detrimental to central nervous system or lungs. Our study aimed to evaluate the effects of repeated exposure to HBO on mitochondrial respiration assessed by high-resolution respirometry (HRR), cell viability estimated by PrestoBlue® reaction, morphology analyzed by routine phase contrast and fluorescent microscopy, and superoxide dismutase (SOD) and citrate synthase (CS) activities using human lung fibroblasts. The cells were exposed to HBO for 2 h per day for 5 consecutive days. One day after the last exposure, HBO cells displayed significantly smaller area and perimeter, compromised viability and elevated SOD activity. No changes were detected in CS activity or quality of mitochondrial network. HRR revealed impaired mitochondrial oxygen consumption manifested by increased leak respiration, decreased activity of complex II and compromised ATP-related oxygen consumption when fatty acids were oxidized. Our findings document that in conditions mimicking chronic intermittent exposure to HBO, lung fibroblasts suffer from compromised mitochondrial respiration linked to complex II and impaired cellular growth in spite of increased antioxidant defense. Underlying mechanism of this HBO-induced mitochondrial dysfunction should be further explored.

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.

Beta burns following radionuclide synovectomy

Radionuclide synovectomy (RSV) is a form of minimally invasive treatment of persistent joint inflammation. The procedure has a high safety profile and the occurrence of serious adverse events, such as full-thickness skin radiation necrosis, is rare. Less severe radiation events, while more common, are usually benign and self-limiting. We present two cases of low-grade beta burns that developed after RSV, despite proper injection technique. The potential long-term risk of such exposure is also discussed, with reference to historical radiation incidents. While low-grade beta burns after RSV usually pose little danger to the patient, any clinician involved in radionuclide treatment of arthritis should be aware of their existence and management.