Hyperbaric Oxygen Therapy Enhanced Circulating Levels of Endothelial Progenitor Cells and Angiogenesis Biomarkers, Blood Flow, in Ischemic Areas in Patients with Peripheral Arterial Occlusive Disease

Hyperbaric oxygen preconditioning rescues prolonged underwater exercise-induced hippocampal dysfunction by regulating microglia activation and polarization

Underwater exercise is becoming increasingly prevalent, during which brain function is necessary but is also at risk. However, no study has explored how prolonged exercise affect the brain in underwater environment. Previous studies have indicated that excessive exercise in common environment causes brain dysfunction but have failed to provide appropriate interventions. Numerous evidence has indicated the neuroprotective effect of hyperbaric oxygen preconditioning (HBO-PC). The objective of this study was to investigate the cognitive effect of prolonged underwater exercise (PUE) and to explore the potential neuroprotective effect of HBO-PC in underwater environment. Rats swimming for 3h in a simulated hyperbaric chamber (2.0 ATA) was used to establish the PUE animal model and HBO-PC (2.5 ATA for 1, 3,5 times respectively) was administrated before PUE. The results demonstrated that PUE triggers anxiety-like behaviors, cognitive impairment accompanied by hippocampal dysfunction, microglia activation and neuroinflammation. Conversely, 3 HBO-PC rescued anxiety-like behaviors and cognitive impairment. Mechanistically, 3 HBO-PC reduced microglia activation and switched the activated microglia from a pro-inflammatory to neuroprotective phenotype. These findings illustrated that PUE induces anxiety-like behaviors and cognitive impairment and HBO-PC of proper frequency may provide an appropriate and less invasive intervention for protecting the brain in underwater exercise.

The link between impaired oxygen supply and cognitive decline in peripheral artery disease

Although peripheral artery disease (PAD) primarily affects large arteries outside the brain, PAD is also associated with elevated cerebral vulnerabilities, including greater risks for brain injury (such as stroke), cognitive decline and dementia. In the present review, we aim to evaluate recent literature and extract information on potential mechanisms linking PAD and consequences on the brain. Furthermore, we suggest novel therapeutic avenues to mitigate cognitive decline and reduce risk of brain injury in patients with PAD. Various interventions, notably exercise, directly or indirectly improve systemic blood flow and oxygen supply and are effective strategies in patients with PAD or cognitive decline. Moreover, triggering protective cellular and systemic mechanisms by modulating inspired oxygen concentrations are emerging as potential novel treatment strategies. While several genetic and pharmacological approaches to modulate adaptations to hypoxia showed promising results in preclinical models of PAD, no clear benefits have yet been clinically demonstrated. We argue that genetic/pharmacological regulation of the involved adaptive systems remains challenging but that therapeutic variation of inspired oxygen levels (e.g., hypoxia conditioning) are promising future interventions to mitigate associated cognitive decline in patients with PAD.

The Mechanisms of Action of Hyperbaric Oxygen in Restoring Host Homeostasis during Sepsis

The perception of sepsis has shifted over time; however, it remains a leading cause of death worldwide. Sepsis is now recognized as an imbalance in host cellular functions triggered by the invading pathogens, both related to immune cells, endothelial function, glucose and oxygen metabolism, tissue repair and restoration. Many of these key mechanisms in sepsis are also targets of hyperbaric oxygen (HBO2) treatment. HBO2 treatment has been shown to improve survival in clinical studies on patients with necrotizing soft tissue infections as well as experimental sepsis models. High tissue oxygen tension during HBO2 treatment may affect oxidative phosphorylation in mitochondria. Oxygen is converted to energy, and, as a natural byproduct, reactive oxygen species are produced. Reactive oxygen species can act as mediators, and both these and the HBO2-mediated increase in oxygen supply have the potential to influence the cellular processes involved in sepsis. The pathophysiology of sepsis can be explained comprehensively through resistance and tolerance to infection. We argue that HBO2 treatment may protect the host from collateral tissue damage during resistance by reducing neutrophil extracellular traps, inhibiting neutrophil adhesion to vascular endothelium, reducing proinflammatory cytokines, and halting the Warburg effect, while also assisting the host in tolerance to infection by reducing iron-mediated injury and upregulating anti-inflammatory measures. Finally, we show how inflammation and oxygen-sensing pathways are connected on the cellular level in a self-reinforcing and detrimental manner in inflammatory conditions, and with support from a substantial body of studies from the literature, we conclude by demonstrating that HBO2 treatment can intervene to maintain homeostasis.

Hyperbaric Oxygen Therapy versus placebo for post-concussion syndrome (HOT-POCS): A randomized, double-blinded controlled pilot study

Post-Concussion Syndrome (PCS) refers to the persistence of physical, cognitive, and emotional symptoms following mild traumatic brain injury (mTBI)/concussion, occurring in roughly 15-30% of individuals. Hyperbaric oxygen therapy (HBOT) has been suggested as a potential treatment for PCS; however, the evidence to date is mixed due to inconsistencies in the treatment protocol and focus on veterans with combat-related injuries, which may not be generalizable to the general population. The goal of Hyperbaric Oxygen Therapy for Post-Concussion Syndrome (HOT-POCS) is to assess the efficacy and safety of HBOT for the treatment of PCS in the civilian population. This randomized, controlled pilot study will be using a standardized HBOT protocol (20 sessions of 100% O₂ at 2.0 atm absolute [ATA]) compared with a true placebo gas system that mimics the oxygen composition at room air (20 sessions of 10.5% O₂ and 89.5% nitrogen at 2.0 ATA) in a cohort of 100 adults with persistent post-concussive symptoms 3-12 months following injury. Change in symptoms on the Rivermead Post-concussion Questionnaire (RPQ) will be the primary outcome of interest. Secondary outcomes include the rate of adverse events, change in the quality of life, and change in cognitive function. Exploratory outcome measures will include changes in physical function and changes in cerebral brain perfusion and oxygen metabolism on MRI brain imaging. Overall, the HOT-POCS study will compare the efficacy of a standardized HBOT treatment protocol against a true placebo gas for the treatment of PCS within 12 months after injury.

Hyperbaric oxygen therapy efficacy on mandibular defect regeneration in rats with diabetes mellitus: an animal study

BACKGROUND

This study aimed to investigate the influence of hyperbaric oxygen therapy on mandibular critical-sized defect regeneration in rats with experimentally induced type I diabetes mellitus. Restoration of large osseous defects in an impaired osteogenic condition such as diabetes mellitus is a challenging task in clinical practice. Therefore, investigating adjunctive therapies to accelerate the regeneration of such defects is crucial.

MATERIALS AND METHODS

Sixteen albino rats were divided into two groups (n = 8/group). To induce diabetes mellitus, a single streptozotocin dosage was injected. Critical-sized defects were created in the right posterior mandibles and filled with beta-tricalcium phosphate graft. The study group was subjected to 90-min sessions of hyperbaric oxygen at 2.4 ATA, for 5 consecutive days per week. Euthanasia was carried out after 3 weeks of therapy. Bone regeneration was examined histologically and histomorphometrically. Angiogenesis was assessed by immunohistochemistry against vascular endothelial progenitor cell marker (CD34) and the microvessel density was calculated.

RESULTS

Exposure of diabetic animals to hyperbaric oxygen resulted in superior bone regeneration and increased endothelial cell proliferation, which were revealed histologically and immunohistochemically, respectively. These results were confirmed by histomorphometric analysis which disclosed a higher percentage of new bone surface area and microvessel density in the study group.

CONCLUSIONS

Hyperbaric oxygen has a beneficial effect on bone regenerative capacity, qualitatively and quantitively, as well as the ability to stimulate angiogenesis.

Hyperbaric Oxygen Therapy for Veterans With Treatment-resistant PTSD: A Longitudinal Follow-up Study

INTRODUCTION

PTSD is common among veteran combatants. PTSD is characterized by brain changes, for which available treatments have shown limited effect. In a short-term study, we showed that hyperbaric oxygen therapy (HBOT) induced neuroplasticity and improved clinical symptoms of veterans with treatment-resistant PTSD. Here, we evaluated the long-term clinical symptoms of the participants of that study.

MATERIALS AND METHODS

Veterans from our short-term study were recruited 1 or more years after completing HBOT. The Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) and self-reported questionnaires were administered at a single site visit. Changes in clinical scores between long-term, short-term, and pretreatment evaluations were analyzed.

RESULTS

Of the 28 participants who received HBOT during or following the short-term study, 22 agreed to participate in the current study. At a mean of 704 ± 230 days after completing the HBOT course, the mean CAPS-5 score (26.6 ± 14.4) was significantly better (lower) than at the pre-HBOT evaluation (47.5 ± 13.1, P < .001) and not statistically different from the short-term evaluation (28.6 ± 16.7, P = .745). However, for the CAPS-5 subcategory D (cognition and mood symptoms), the mean score was significantly better (lower) at long-term than at short-term evaluation (7.6 ± 5.1 vs. 10.0 ± 6.0, P < .001). At the long-term compared to the pretreatment evaluation, higher proportions of the participants were living with life partners (10 (46%) vs. 17 (77%), P = .011) and were working (9 (41%) vs. 16 (73%), P = .033). Decreases were observed between pretreatment and the long-term follow-up, in the number of benzodiazepine users (from 10 (46%) to 4 (18%), P = .07) and in the median (range) cannabis daily dose (from 40.0 g (0-50) to 22.5 g (0-30), P = .046).

CONCLUSIONS

The beneficial clinical effects of HBOT are persistent and were not attenuated at long-term follow-up of about 2 years after completion of HBOT. Additional long-term effects of the treatment were observed in social function and in decreased medication use.

Rejuvenated endothelial progenitor cells through overexpression of cellular prion protein effectively salvaged the critical limb ischemia in rats with preexisting chronic kidney disease

BACKGROUND

This study tested the hypothesis that overexpression of cellular prion protein in endothelial progenitor cells (PrPc^OE-EPCs), defined as "rejuvenated EPCs," was superior to EPCs for salvaging the critical limb ischemia (CLI) induced after 28-day chronic kidney disease (CKD) induction in rat.

METHODS AND RESULTS

Cell viability and flow cytometric analyses of early/late apoptosis/total-intracellular ROS/cell cycle (sub-G1, G2/M phase) were significantly higher in EPCs + H₂O₂ than in EPCs that were significantly reversed in PrPc^OE-EPCs + H₂O₂ (all p < 0.001). The protein expressions of inflammation (IL-1ß/IL-6/MMP-9/p-NF-κB) were significantly increased in EPC + TNF-α than in EPCs that were significantly reversed in PrPc^OE-EPCs + TNF-α (all p < 0.001). Adult-male SD rats (n = 8/each group) were categorized into group 1 (sham-operated control), group 2 (CKD + CLI), group 3 [CKD + CLI + EPCs by intravenous (0.6 × 10⁵)/intra-muscular (0.6 × 10⁵) injections at 3 h after CLI induction], group 4 (CKD + CLI + PrPc^OE-EPCs/dose-administration as group 3) and group 5 (CKD + CLI + siPrnp-EPCs/dose-administration as group 3). By day 14 after CLI induction, the ratio of ischemia to normal blood flow (INBF) in CLI area was highest in group 1/lowest in group 2/significantly higher in group 4 than in groups 3/5 and significantly higher in group 3 than in group 5 (all p < 0.0001). Histopathology demonstrated that the angiogenesis (number of small vessels/CD31 + cells) exhibited a similar trend, whereas the fibrosis/kidney injury score exhibited an opposite pattern of INBF among the groups (all p < 0.0001). The protein expressions of angiogenesis (SDF-1α/VEGF/CXCR4)/cell-stress signaling (p-PI3K/p-Akt/p-m-TOR) were significantly and progressively increased from groups 1-4 that were reversed in group 5 (all p < 0.0001). The protein expressions of fibrotic (p-Smad3/TGF-ß)/oxidative-stress (NOX-1/NOX-2/oxidized-protein)/apoptotic (mitochondrial-Bax/cleaved caspase3/cleaved PARP)/mitochondrial-damaged (cytosolic-cytochrome-C) biomarkers displayed an opposite pattern of INBF among the groups (all p < 0.0001).

CONCLUSION

PrPc^OE-EPCs were superior to EPCs only therapy for salvaging the CLI.

Fluorescence detection of the human angiotensinogen protein by the G-quadruplex aptamer

Schematic diagram of AGT detection by a G-quadruplex based fluorescent biosensor.

Combined Treatment With Hyperbaric Oxygen Therapy and Endovascular Therapy for Patients With Chronic Limb-Threatening Ischemia - Study Protocol for the HOTFOOT Multicenter Randomized Controlled Trial

Background: Hyperbaric oxygen therapy (HBOT) is regarded as one of the therapeutic options added to standard care to improve lower-limb outcomes in patients with chronic limb-threatening ischemia (CLTI). However, the current guidelines specify that HBOT should not be offered instead of revascularization to prevent limb loss in CLTI patients. The aim of the HOTFOOT study is to examine the impact of HBOT on wound healing in CLTI patients after successful endovascular therapy (EVT).

Methods and Results: The HOTFOOT study is a multicenter prospective randomized open blinded-endpoint trial that is to be conducted at 10 trial centers in Japan between February 2021 and February 2022. This study will enroll 140 patients with CLTI receiving successful EVT. Eligible participants will be allocated 1 : 1 to either the EVT+HBOT or EVT group; participants in the EVT+HBOT group will receive 30 HBOT sessions. The primary outcome is the time to complete wound healing over the 6-month follow-up. Secondary outcomes during the 6-month follow-up are the proportion of patients who achieved complete wound healing, freedom from major lower-limb amputation, amputation-free survival, and freedom from target lesion reintervention.

Conclusions: This study is expects to assess whether HBOT, in combination with successful EVT, can improve lower-limb outcomes in CLTI patients.

Hyperbaric Oxygen Treatment: Effects on Mitochondrial Function and Oxidative Stress

Hyperbaric oxygen treatment (HBOT)—the administration of 100% oxygen at atmospheric pressure (ATA) greater than 1 ATA—increases the proportion of dissolved oxygen in the blood five- to twenty-fold. This increase in accessible oxygen places the mitochondrion—the organelle that consumes most of the oxygen that we breathe—at the epicenter of HBOT’s effects. As the mitochondrion is also a major site for the production of reactive oxygen species (ROS), it is possible that HBOT will increase also oxidative stress. Depending on the conditions of the HBO treatment (duration, pressure, umber of treatments), short-term treatments have been shown to have deleterious effects on both mitochondrial activity and production of ROS. Long-term treatment, on the other hand, improves mitochondrial activity and leads to a decrease in ROS levels, partially due to the effects of HBOT, which increases antioxidant defense mechanisms. Many diseases and conditions are characterized by mitochondrial dysfunction and imbalance between ROS and antioxidant scavengers, suggesting potential therapeutic intervention for HBOT. In the present review, we will present current views on the effects of HBOT on mitochondrial function and oxidative stress, the interplay between them and the implications for several diseases.

Hyperbaric Oxygen Treatment-From Mechanisms to Cognitive Improvement

Hyperbaric oxygen treatment (HBOT)—the medical use of oxygen at environmental pressure greater than one atmosphere absolute—is a very effective therapy for several approved clinical situations, such as carbon monoxide intoxication, incurable diabetes or radiation-injury wounds, and smoke inhalation. In recent years, it has also been used to improve cognition, neuro-wellness, and quality of life following brain trauma and stroke. This opens new avenues for the elderly, including the treatment of neurological and neurodegenerative diseases and improvement of cognition and brain metabolism in cases of mild cognitive impairment. Alongside its integration into clinics, basic research studies have elucidated HBOT’s mechanisms of action and its effects on cellular processes, transcription factors, mitochondrial function, oxidative stress, and inflammation. Therefore, HBOT is becoming a major player in 21st century research and clinical treatments. The following review will discuss the basic mechanisms of HBOT, and its effects on cellular processes, cognition, and brain disorders.

Integrative Role of Hyperbaric Oxygen Therapy on Healthspan, Age-Related Vascular Cognitive Impairment, and Dementia

Growing life expectancy will contribute to the on-going shift towards a world population increasingly comprised of elderly individuals. This demographic shift is associated with a rising prevalence of age-related diseases, among all age-related pathologies it has become crucial to understand the age-associated cognitive changes that remain a major risk factor for the development of vascular cognitive impairment and dementia (VCID). Furthermore, age-related Alzheimer's disease and other neurogenerative diseases with vascular etiology are the most prominent contributing factors for the loss of cognitive function observed in aging. Hyperbaric Oxygen Therapy (HBOT) achieves physiologic effects by increasing oxygen tension (PO2), raising oxygen tissue levels, decreasing intracranial pressure and relieving cerebral edema. Many of the beneficial effects of HBOT exert their protective effects at the level of the microcirculation. Furthermore, the microcirculation's exquisite pervasive presence across every tissue in the body, renders it uniquely able to influence the local environment of most tissues and organs, including the brain. As such, treatments aimed at restoring aging-induced functional and structural alterations of the cerebral microcirculation may potentially contribute to the amelioration of a range of age-related pathologies including vascular cognitive impairment, Alzheimer's disease, and vascular dementias. Despite the presented evidence, the efficacy and safety of HBOT for the treatment of age-related vascular cognitive impairment and dementia remains understudied. The present review aims to examine the existing evidence indicative of a potential therapeutic role for HBOT-induced hyperoxia against age-related cerebromicrovascular pathologies contributing to cognitive impairment, dementia and decreased healthspan in the elderly.

The Effects of Hyperbaric Oxygenation on Oxidative Stress, Inflammation and Angiogenesis

Hyperbaric oxygen therapy (HBOT) is commonly used as treatment in several diseases, such as non-healing chronic wounds, late radiation injuries and carbon monoxide poisoning. Ongoing research into HBOT has shown that preconditioning for surgery is a potential new treatment application, which may reduce complication rates and hospital stay. In this review, the effect of HBOT on oxidative stress, inflammation and angiogenesis is investigated to better understand the potential mechanisms underlying preconditioning for surgery using HBOT. A systematic search was conducted to retrieve studies measuring markers of oxidative stress, inflammation, or angiogenesis in humans. Analysis of the included studies showed that HBOT-induced oxidative stress reduces the concentrations of pro-inflammatory acute phase proteins, interleukins and cytokines and increases growth factors and other pro-angiogenesis cytokines. Several articles only noted this surge after the first HBOT session or for a short duration after each session. The anti-inflammatory status following HBOT may be mediated by hyperoxia interfering with NF-κB and IκBα. Further research into the effect of HBOT on inflammation and angiogenesis is needed to determine the implications of these findings for clinical practice.

Umbilical cord-derived MSC and hyperbaric oxygen therapy effectively protected the brain in rat after acute intracerebral haemorrhage

This study tested the hypothesis that combined therapy with human umbilical cord‐derived mesenchymal stem cells (HUCDMSCs) and hyperbaric oxygen (HBO) was superior to either one on preserving neurological function and reducing brain haemorrhagic volume (BHV) in rat after acute intracerebral haemorrhage (ICH) induced by intracranial injection of collagenase. Adult male SD rats (n = 30) were equally divided into group 1 (sham‐operated control), group 2 (ICH), group 3 (ICH +HUCDMSCs/1.2 × 10⁶ cells/intravenous injection at 3h and days 1 and 2 after ICH), group 4 (ICH +HBO/at 3 hours and days 1 and 2 after ICH) and group 5 (ICH +HUCDMSCs‐HBO), and killed by day 28 after ICH. By day 1, the neurological function was significantly impaired in groups 2‐5 than in group 1 (P < .001), but it did not differ among groups 2 to 5. By days 7, 14 and 28, the integrity of neurological function was highest in group 1, lowest in group 2 and significantly progressively improved from groups 3 to 5 (all P < .001). By day 28, the BHV was lowest in group 1, highest in group 2 and significantly lower in group 5 than in groups 3/4 (all P < .0001). The protein expressions of inflammation (HMGB1/TLR‐2/TLR‐4/MyD88/TRAF6/p‐NF‐κB/IFN‐γ/IL‐1ß/TNF‐α), oxidative stress/autophagy (NOX‐1/NOX‐2/oxidized protein/ratio of LC3B‐II/LC3B‐I) and apoptosis (cleaved‐capspase3/PARP), and cellular expressions of inflammation (CD14+, F4/80+) in brain tissues exhibited an identical pattern, whereas cellular levels of angiogenesis (CD31+/vWF+/small‐vessel number) and number of neurons (NeuN+) exhibited an opposite pattern of BHV among the groups (all P < .0001). These results indicate that combined HUCDMSC‐HBO therapy offered better outcomes after rat ICH.

Hyperbaric Oxygen Improves Cerebral Ischemia/Reperfusion Injury in Rats Probably via Inhibition of Autophagy Triggered by the Downregulation of Hypoxia-Inducing Factor-1 Alpha

Ischemic stroke, accompanied with high mortality and morbidity, may produce heavy economic burden to societies and families. Therefore, it is of great significance to explore effective therapies. Hyperbaric oxygen (HBO) is a noninvasive, nondrug treatment method that has been proved able to save ischemic penumbra by improving hypoxia, microcirculation, and metabolism and applied in various ischemic diseases. Herewith, we fully evaluated the effect of HBO on ischemic stroke and investigated its potential mechanism in the rat ischemia/reperfusion(I/R) model. Sixty Sprague-Dawley male rats were randomly divided into three groups—sham group, MCAO group, and MCAO+HBO group. In the latter two groups, the middle cerebral artery occlusion was performed (MCAO) for 2 hours, and then the occlusion was removed in order to establish the ischemic/reperfusion model. Subsequently, HBO was performed immediately after I/R (2 hours per day for 3 days). 72 hours after MCAO, the brain was dissected for our experiment. Finally, the data from three groups were analyzed by one-way analysis of variance (ANOVA) and followed by a Bonferroni test. In this article, we reported that HBO effectively reduced the infarction and edema and improved neurological functions to a certain extent. As shown by western blot analysis, HBO significantly reduced autophagy by regulating autophagy-related proteins (mTOR, p-mTOR, Atg13, LC3B II and LC3B II) in the hippocampus 72 hours after I/R, which was accompanied by inhibiting the expression of hypoxia inducible factor-1α (HIF-1α) in hippocampus. The results suggest that HBO may improve cerebral I/R injury, possibly via inhibiting HIF-1α, the upstream molecule of autophagy, and therefore, subsequently inhibiting autophagy in the rat model of ischemic stroke.

Intussusceptive Angiogenesis and Peg-Socket Junctions between Endothelial Cells and Smooth Muscle Cells in Early Arterial Intimal Thickening

Angiogenesis in arterial intimal thickening (AIT) has been considered mainly in late AIT stages and only refers to sprouting angiogenesis. We assess angiogenesis during early AIT development and the occurrence of the intussusceptive type. For this purpose, we studied AIT development in (a) human arteries with vasculitis in gallbladders with acute cholecystitis and urgent (n = 25) or delayed (n = 20) cholecystectomy, using immunohistochemical techniques and (b) experimentally occluded arterial segments (n = 56), using semithin and ultrathin sections and electron microscopy. The results showed transitory angiogenic phenomena, with formation of an important microvasculature, followed by vessel regression. In addition to the sequential description of angiogenic and regressive findings, we mainly contribute (a) formation of intravascular pillars (hallmarks of intussusception) during angiogenesis and vessel regression and (b) morphological interrelation between endothelial cells (ECs) in the arterial wall and vascular smooth muscle cells (VSMCs), which adopt a pericytic arrangement and establish peg-and-socket junctions with ECs. In conclusion, angiogenesis and vessel regression play an important role in AIT development in the conditions studied, with participation of intussusceptive angiogenesis during the formation and regression of a provisional microvasculature and with morphologic interrelation between ECs and VSMCs.

Circulatory Rejuvenated EPCs Derived from PAOD Patients Treated by CD34+ Cells and Hyperbaric Oxygen Therapy Salvaged the Nude Mouse Limb against Critical Ischemia

This study tested whether circulatory endothelial progenitor cells (EPCs) derived from peripheral arterial occlusive disease (PAOD) patients after receiving combined autologous CD34+ cell and hyperbaric oxygen (HBO) therapy (defined as rejuvenated EPCs) would salvage nude mouse limbs against critical limb ischemia (CLI). Adult-male nude mice (n = 40) were equally categorized into group 1 (sham-operated control), group 2 (CLI), group 3 (CLI-EPCs (6 × 10⁵) derived from PAOD patient’s circulatory blood prior to CD34⁺ cell and HBO treatment (EPC^Pr-T) by intramuscular injection at 3 h after CLI induction) and group 4 (CLI-EPCs (6 × 10⁵) derived from PAOD patient’s circulatory blood after CD34⁺ cell and HBO treatment (EPC^Af-T) by the identical injection method). By 2, 7 and 14 days after the CLI procedure, the ischemic to normal blood flow (INBF) ratio was highest in group 1, lowest in group 2 and significantly lower in group 4 than in group 3 (p < 0.0001). The protein levels of endothelial functional integrity (CD31/von Willebrand factor (vWF)/endothelial nitric-oxide synthase (eNOS)) expressed a similar pattern to that of INBF. In contrast, apoptotic/mitochondrial-damaged (mitochondrial-Bax/caspase-3/PARP/cytosolic-cytochrome-C) biomarkers and fibrosis (Smad3/TGF-ß) exhibited an opposite pattern, whereas the protein expressions of anti-fibrosis (Smad1/5 and BMP-2) and mitochondrial integrity (mitochondrial-cytochrome-C) showed an identical pattern of INBF (all p < 0.0001). The protein expressions of angiogenesis biomarkers (VEGF/SDF-1α/HIF-1α) were progressively increased from groups 1 to 3 (all p < 0.0010). The number of small vessels and endothelial cell surface markers (CD31⁺/vWF⁺) in the CLI area displayed an identical pattern of INBF (all p < 0.0001). CLI automatic amputation was higher in group 2 than in other groups (all p < 0.001). In conclusion, EPCs from HBO-C34+ cell therapy significantly restored the blood flow and salvaged the CLI in nude mice.

Association between regional economic status and renal recovery of dialysis-requiring acute kidney injury among critically ill patients

The association between regional economic status and the probability of renal recovery among patients with dialysis-requiring AKI (AKI-D) is unknown. The nationwide prospective multicenter study enrolled critically ill adult patients with AKI-D in four sampled months (October 2014, along with January, April, and July 2015) in Taiwan. The regional economic status was defined by annual disposable income per capita (ADIPC) of the cities the hospitals located. Among the 1,322 enrolled patients (67.1 ± 15.5 years, 36.2% female), 833 patients (63.1%) died, and 306 (23.1%) experienced renal recovery within 90 days following discharge. We categorized all patients into high (n = 992) and low economic status groups (n = 330) by the best cut-point of ADIPC determined by the generalized additive model plot. By using the Fine and Gray competing risk regression model with mortality as a competing risk factor, we found that the independent association between regional economic status and renal recovery persisted from model 1 (no adjustment), model 2 (adjustment to basic variables), to model 3 (adjustment to basic and clinical variables; subdistribution hazard ratio, 1.422; 95% confidence interval, 1.022–1.977; p = 0.037). In conclusion, high regional economic status was an independent factor for renal recovery among critically ill patients with AKI-D.

The effect of continuous diffusion of oxygen treatment on cytokines, perfusion, bacterial load, and healing in patients with diabetic foot ulcers

To evaluate continuous diffusion of oxygen therapy (CDO) on cytokines, perfusion, and bacterial load in diabetic foot ulcers we evaluated 23 patients for 3 weeks. Tissues biopsies were obtained at each visit to evaluate cytokines and quantitative bacterial cultures. Perfusion was measured with hyperspectral imaging and transcutaneous oxygen. We used paired T tests to compare continuous variables and independent T tests to compare healers and nonhealers. There was an increase from baseline to week 1 in TGF-β (P = .008), TNF-α (P = .014), VEGF (P = .008), PDGF (P = .087), and IGF-1 (P = .058); baseline to week 2 in TGF-β (P = .010), VEGF (P = .051), and IL-6 (P = .031); and baseline to week 3 with TGF-β (P = .055) and IL-6 (P = .054). There was a significant increase in transcutaneous oxygen after 1 week of treatment on both medial and lateral foot (P = .086 and .025). Fifty-three percent of the patients had at least a 50% wound area reduction (healers). At baseline, there were no differences in cytokines between healers and nonhealers. However, there was an increase in CXCL8 after 1 week of treatment (P = .080) and IL-6 after 3 weeks of treatment in nonhealers (P = .099). There were no differences in quantitative cultures in healers and nonhealers.

Protective effect of combined therapy with hyperbaric oxygen and autologous adipose-derived mesenchymal stem cells on renal function in rodent after acute ischemia-reperfusion injury

BACKGROUND

This study tested the hypothesis that combined hyperbaric oxygen (HBO) and autologous adipose-derived mesenchymal stem cell (ADMSC) therapy was superior to either alone at protecting renal function in rodents after acute ischemia-reperfusion (IR) injury.

METHODS AND RESULTS

Adult-male SD rats (n = 40) were equally categorized: group 1 (sham-operated control); group 2 (IR + 50 μg medium intra-renal artery administration); group 3 [IR + HBO (at 1.5 h and days 1 and 2 after IR)]; group 4 [IR + ADMSC (2.0×10⁶ cells/5.0×10⁵/per each renal artery and 1.0×10⁶ by intravenous injection at 1.5 h after IR]; and group 5 (IR + HBO-ADMSC). By 72 hr after IR, the circulating levels of BUN/creatinine and ratio of urine protein/creatinine were significantly highest in group 2, lowest in group 1, significantly increased in group 5 than in groups 3 and 4, but not different between latter two groups, whereas the circulating levels of EPCs and soluble-angiogenesis biomarkers (SDF-1α/HIF-1α) exhibited an opposite pattern to BUN/creatinine among the five groups (all P<0.001). The kidney injury score, ROS (fluorescent intensity of H₂DCFDA dye in kidney), inflammation (F4/80+, CD14+ cells) and glomerular-tubular injury score (WT-1/KIM-1) displayed an identical pattern whereas the integrity of podocyte components exhibited an opposite pattern to BUN/creatinine among the five groups (all P<0.0001). The protein expressions of inflammatory (MMP-9/TNF-α/NF-κB/ICAM-1), oxidative-stress (NOX-1/NOx-2/oxidized protein) and apoptotic (mitochondrial-Bax/cleaved-caspase3/PARP) markers showed an identical pattern to BUN/creatinine (all P<0.001).

CONCLUSION

Combined ADMSC-HBO therapy was superior to either one alone at protecting the kidney from acute IR injury.

The Hyperoxic-Hypoxic Paradox

Effective metabolism is highly dependent on a narrow therapeutic range of oxygen. Accordingly, low levels of oxygen, or hypoxia, are one of the most powerful inducers of gene expression, metabolic changes, and regenerative processes, including angiogenesis and stimulation of stem cell proliferation, migration, and differentiation. The sensing of decreased oxygen levels (hypoxia) or increased oxygen levels (hyperoxia), occurs through specialized chemoreceptor cells and metabolic changes at the cellular level, which regulate the response. Interestingly, fluctuations in the free oxygen concentration rather than the absolute level of oxygen can be interpreted at the cellular level as a lack of oxygen. Thus, repeated intermittent hyperoxia can induce many of the mediators and cellular mechanisms that are usually induced during hypoxia. This is called the hyperoxic-hypoxic paradox (HHP). This article reviews oxygen physiology, the main cellular processes triggered by hypoxia, and the cascade of events triggered by the HHP.

The Hyperoxic-Hypoxic Paradox

Effective metabolism is highly dependent on a narrow therapeutic range of oxygen. Accordingly, low levels of oxygen, or hypoxia, are one of the most powerful inducers of gene expression, metabolic changes, and regenerative processes, including angiogenesis and stimulation of stem cell proliferation, migration, and differentiation. The sensing of decreased oxygen levels (hypoxia) or increased oxygen levels (hyperoxia), occurs through specialized chemoreceptor cells and metabolic changes at the cellular level, which regulate the response. Interestingly, fluctuations in the free oxygen concentration rather than the absolute level of oxygen can be interpreted at the cellular level as a lack of oxygen. Thus, repeated intermittent hyperoxia can induce many of the mediators and cellular mechanisms that are usually induced during hypoxia. This is called the hyperoxic-hypoxic paradox (HHP). This article reviews oxygen physiology, the main cellular processes triggered by hypoxia, and the cascade of events triggered by the HHP.

Combined Therapy With Hyperbaric Oxygen and Melatonin Effectively Reduce Brain Infarct Volume and Preserve Neurological Function After Acute Ischemic Infarct in Rat

This study tested the hypothesis that combined hyperbaric oxygen (HBO) and melatonin (Mel) was superior to either one for protecting the brain functional and parenchymal integrity from acute ischemic stroke (IS) injury. Adult-male Sprague-Dawley rats were divided into groups 1 (sham-operated control), 2 (IS), 3 (IS + HBO), 4 (IS + Mel), and 5 (IS + HBO-Mel). By day 28 after IS, the brain infarct area (BIA) was lowest in group 1, highest in group 2, significantly higher in groups 3 and 4 than in group 5, but not different between groups 3 and 4. The neurological function at day 7, 14, and 28 exhibited an opposite pattern to BIA among the 5 groups. The protein expressions of inflammatory (IL-1β/IL-6/iNOS/TNF-α/p-NF-κB), apoptotic (cleaved-caspase3/cleaved-PARP/mitochondrial Bax), mitochondrial/DNA-damaged (cytochrome-C/γ-H2AX), oxidative stress (NOX-1/NOX-2), and autophagy (i.e. ratio of CL3B-II/CL3B-I) biomarkers displayed an identical pattern of BIA among 5 groups. Cellular expressions of inflammation (F4/80+/GFAP+) and DNA-damaged biomarker (γ-H2AX+) exhibited an identical pattern, whereas the integrities of myelin sheath/neuron (MPB+/NeuN+), endothelial cell (CD31+/vWF+), and number of small vessels exhibited an opposite pattern of BIA among the 5 groups. Combined HBO-Mel therapy offered an additional benefit in protecting the brain against IS injury.

The effect of hyperbaric oxygenation therapy on myocardial function

Hyperbaric oxygenation therapy is successfully implemented for the treatment of several disorders. Data on the effect of hyperbaric oxygenation on echocardiographic parameters in asymptomatic patients is limited. The current study sought to evaluate the effect of hyperbaric oxygenation therapy on echocardiographic parameters in asymptomatic patients. Thirty-one consecutive patients underwent a 60-sessions course of hyperbaric oxygenation therapy in an attempt to improve cognitive impairment. In all subjects, echocardiography examination was performed before and after a course of hyperbaric oxygenation therapy. Conventional and speckle tracking imaging parameters were calculated and analyzed. The mean age was 70 ± 9.5 years, 28 [90%] were males. History of coronary artery disease was present in 12 [39%]. 94% suffered from hypertension, 42% had diabetes mellitus. Baseline wall motion abnormalities were found in eight patients, however, global ejection fraction was within normal limits. During the study, ejection fraction [EF], increased from 60.71 ± 6.02 to 62.29 ± 5.19%, p = 0.02. Left ventricular end systolic volume [LVESV], decreased from 38.08 ± 13.30 to 35.39 ± 13.32 ml, p = 0.01. Myocardial performance index [MPi] improved, from 0.29 ± 0.07 to 0.26 ± 0.08, p = 0.03. Left ventricular [LV] global longitudinal strain increased from - 19.31 ± 3.17% to - 20.16 ± 3.34%, p = 0.036 due to improvement in regional strain in the apical and antero-septal segments. Twist increased from 18.32 ± 6.61° to 23.12 ± 6.35° p = 0.01, due to improvement in the apical rotation, from 11.76 ± 4.40° to 16.10 ± 5.56°, p = 0.004. Hyperbaric oxygen therapy appears to improve left ventricular function, especially in the apical segments, and is associated with better cardiac performance. If our results are confirmed in further studies, HBOT can be used in many patients with heart failure and systolic dysfunction.

Development and Evaluation of a Prototype Scratch Apparatus for Wound Assays Adjustable to Different Forces and Substrates

Scratch assays enable the study of the migration process of an injured adherent cell layer in vitro. An apparatus for the reproducible performance of scratch assays and cell harvesting has been developed that meets the requirements for reproducibility in tests as well as easy handling. The entirely autoclavable setup is divided into a sample translation and a scratching system. The translational system is compatible with standard culture dishes and can be modified to adapt to different cell culture systems, while the scratching system can be adjusted according to angle, normal force, shape, and material to adapt to specific questions and demanding substrates. As a result, a fully functional prototype can be presented. This system enables the creation of reproducible and clear scratch edges with a low scratch border roughness within a monolayer of cells. Moreover, the apparatus allows the collection of the migrated cells after scratching for further molecular biological investigations without the need for a second processing step. For comparison, the mechanical properties of manually performed scratch assays are evaluated.

Hyperbaric Oxygen Treatment Ameliorates Hearing Loss and Auditory Cortex Injury in Noise Exposed Mice by Repressing Local Ceramide Accumulation

Noise-induced hearing loss (NIHL) relates closely to auditory cortex (AC) injury, so countermeasures aiming at the AC recovery would be of benefit. In this work, the effect of hyperbaric oxygen treatment on NIHL was elucidated, which was imposed on mice before (HBOP), during (HBOD) or after (HBOA) noise exposure. Morphology of neurons was assayed by hematoxylin-eosin or Nissl staining. Ceramide (Cer) level was measured through immunohistochemistry analysis. Apoptotic neurons were counted using transferase-mediated dUTP nick end labeling (TUNEL) staining. We demonstrated that the intense, broad band noise raised the threshold of auditory brainstem response, evoked neuronal degeneration or apoptosis and triggered the Cer accumulation in AC, all of which were restored significantly by HBOP, but not HBOD or HBOA. Cer over-generation reversed the advantages of HBOP significantly, while its curtailment recapitulated the effect. Next, noise exposure raised the superoxide or malondialdehyde (MDA) production which was blocked by HBOP or Cer repression. Oxidative control not only attenuated the hearing loss or neurodegeneration but, in turn, reduced the Cer formation significantly. In summary, mutual regulation between Cer and oxidative stress underlies the HBOP’s curative effect on hearing loss and neuronal damage in noise-exposed mice.