Hyperbaric oxygen therapy for the management of chronic wounds

A Refractory Livedoid Vasculopathy Accompanied by Methylene Tetrahydrofolate Reductase Gene Polymorphism Successfully Treated with Hyperbaric Oxygen Therapy

Livedoid vasculopathy (LV) is a chronic coagulation disorder characterized by recurrent, painful ulcers on the lower extremities. Methylene tetrahydrofolate reductase (MTHFR) gene polymorphism is associated with coagulopathy. Therapeutic options usually include anti-inflammatory or immunosuppressive agents. However, the condition is still highly challenging to manage and no consensus over the first-line treatment for LV exists. Furthermore, when LV is accompanied with MTHFR gene polymorphism, clinical presentations could be more severe and resistant to treatment. We report a case of refractory LV accompanied by MTHFR gene polymorphism, which was successfully treated with hyperbaric oxygen therapy (HBOT). A 63-year-old female patient presented with multiple painful ulcers, atrophie blanches, and retiform purpura on both lower legs and feet. Histopathologic findings were compatible with LV. LV was diagnosed based on these clinicopathological findings. Following the diagnosis, we treated the patient with pentoxifylline, aspirin, systemic corticosteroid, antihistamine, and antibiotics. In spite of six-month treatment, the skin lesions did not improve; hence, HBOT was performed. It was performed at 2.0 absolute atmosphere for 120 minutes each time, three times a week. After 4 sessions, the ulcers began to heal and after 13 sessions, the skin lesions almost healed. During the eight-month follow-up period, the skin ulcers did not recur and the symptoms remained stable. Additionally, it was confirmed that she had MTHFR gene polymorphism after a genetic test. In conclusion, we wish to provide evidence regarding the effectiveness of HBOT and suggest that HBOT might be a considerable treatment option in refractory LV.

Antibacterial and Anti-inflammatory Activity of Extracts and Major Constituents Derived from Stachytarpheta indica Linn. Leaves and Their Potential Implications for Wound Healing

Wounds of various types continue to have a severe socioeconomic impact on the cost of health care. Globally, there has been increased interest surrounding the identification of bioactive compounds that promote or modulate the wound healing process. Stachytarpheta indica Linn. is traditionally used to heal wounds and relieve inflammation; however, the theorised pharmacological properties have not yet been scientifically validated. In this study, dried and ground plant leaves were extracted with water and methanol, which were then subjected to various analyses. The antimicrobial activity of the plant extracts and isolated compounds was determined using well diffusion assays, while the minimum inhibitory concentrations were determined with a colorimetric assay. Morphological changes of human keratinocytes in response to plant extracts were observed with differential interference contrast microscope imaging. Cell viability, proliferation, and migratory effects post-treatment with the plant extracts were also evaluated via colorimetric cytotoxicity assays and a real-time cell analyser protocol. Anti-inflammatory effects of plant extracts and isolated compounds were evaluated by flow cytometry and cyclooxygenase and lipoxygenase enzyme inhibition assays. Three active compounds, i.e. ipolamiide, verbascoside and iso-verbascoside, were isolated from S. indica leaves. Verbascoside demonstrated broad-range antibacterial activity and imposed strong inhibition at 9.77 μg/mL against Staphylococci spp. S. indica extracts (0.1-0.2 mg/mL) were shown to improve human keratinocyte proliferation up to 60% and induce morphological changes by producing cytoplasmic projections at concentrations higher than 0.4 mg/mL. Plant extracts (6.25-100 μg/mL) and individual compounds (3.125-50 μg/mL) elicited strong anti-inflammatory effects by suppressing the expression of interleukin-8 and inhibiting cyclooxygenase-1 and 5-lipoxygenase enzymes. Collectively, these results indicate that plant extracts and isolated compounds derived from S. indica have the potential to inhibit bacterial growth, promote tissue regeneration and reduce inflammation, hence, potentially providing the basis for a novel therapeutic for the treatment of wounds.

The effect of hyperbaric oxygen therapy on central macular thickness and choroidal thickness in the healthy eyes of patients with idiopathic sudden sensorineural hearing loss

PURPOSE

To evaluate the effect of hyperbaric oxygen therapy (HBOT) for idiopathic sudden sensorineural hearing loss (ISSNHL) on central macular thickness (CMT) and choroidal thickness (CT).

MATERIALS AND METHODS

The study included 42 healthy eyes of 21 patients with ISSNHL (aged 24-61 years) who started HBOT within the first three days of the onset of hearing loss. Duration and severity of hearing loss were noted before starting HBOT. Central macular thickness (CMT), choroidal thickness (CT) 1500 µm nasal and temporal of the fovea, and subfoveal CT were measured by spectral domain optic coherence tomography before the first session of HBOT and after sessions 10 and 20. measurements obtained before and after HBOT were compared.

RESULTS

Eleven patients (52.4%) were men and 10 (47.6%) were women. The mean age was 44.67 ± 10.1 years. The mean duration of sudden hearing loss before HBOT was 2.05 ± 1 day. Hearing loss was mild in 5 patients, moderate in 5 patients, moderate to severe in 2 patients, severe in 4 patients and profound in 5 patients. Comparison of measurements obtained before HBOT and after 10 and 20 sessions of HBOT revealed no significant differences in CMT (219.17 ± 22.91, 220.33 ± 19.66, and 220.21 ± 19.3 µm), subfoveal CT (347.71 ± 66.82, 348.38 ± 74.55, and 345.45 ± 75.39 µm), nasal CT (328.64 ± 82.31, 316.02 ± 79.32, and 313.52 ± 89.92 µm), or temporal CT (321.76 ± 71.29, 317.05 ± 73.94, and 314.05 ± 74.61 µm, respectively) (p > 0.05).

CONCLUSIONS

HBOT for the treatment of ISSNHL had no significant effect on CMT or CT in healthy eyes.

Advances and impact of arginine-based materials in wound healing

In studies on wound-dressing materials, bioactive materials have been developed rapidly to accelerate wound healing. In recent years, scientists have studied arginine as a bioactive component due to its excellent biosafety, antimicrobial properties and therapeutic effects on wound healing. Surprisingly, arginine therapy is also used under specific pathological conditions, such as diabetes and trauma/hemorrhagic shock. Due to the broad utilization of arginine-assisted therapy, we present the unique properties of arginine for healing lesions of damaged tissue and examined multiple arginine-based systems for the application of wound healing. This review shows that arginine-based therapy can be separated in two categories: direct supplemental approaches of free arginine, and indirect approaches based on arginine derivatives in which modified arginine can be released after biodegradation. Using these two pathways, arginine-based therapy may prove to be a promising strategy in the development of wound curative treatments.

The effect of hyperbaric oxygen therapy on retinal thickness and progression of retinopathy in patients with Type 2 diabetes: a prospective cohort study

Purpose: Evaluation of the effect of hyperbaric oxygen therapy (HBOT) on the progression of retinopathy, choroidal and retinal thickness in patients with type 2 diabetes mellitus (DM). Materials and methods: This prospective non-randomized cohort study consisted of 60 eyes of 30 patients who received 30 sessions of HBOT for a diabetic foot ulcer (DFU). The participants were divided into three groups; group 1: mild-moderate non-proliferative diabetic retinopathy (DRP) (n = 14), group 2: severe non-proliferative DRP (n = 20) and group 3: DRP without active proliferative findings with the applied laser for at least 2 years (n = 26). The cases were examined on base-line (measurement-1), after the 10th session of HBOT (Measurement-2), after the 20th session of HBOT (Measurement-3), after the 30th session of HBOT (Measurement-4), and after 10 days of the last session of HBOT (Measurement-5). The changes in central macular thickness (CMT; subfoveal point [CMT-SF], nasal point [CMT-N] and temporal point [CMT-T]), central choroidal thickness (CCT; subfoveal point [CCT-SF], nasal point [CCT-N] and temporal point [CCT-T]), and the stage of DRP were compared. Results: There was no significant difference between groups in terms of change ratio (CR%) in CMT-SF and CMT-N values. However, in Measurement-3, CR% in CMT-T was significantly higher in group 1 (p = 0.019). A significant increase in CMT-N and CMT-T parameters over time was observed in Group 1 (p < 0.05). There was a significant decrease in CCT-SF, CCT-N, and CCT-T values with time in each of the three groups (p < 0.05). At the end of HBOT, there was no progression or regression in the stage of DRP in any group. Conclusions: HBOT has both a thinning effect on the choroid layer in all three groups and a thickening effect on the macula in the mild-moderate non-proliferative diabetic eyes.

Non-thermal atmospheric plasma ameliorates imiquimod-induced psoriasis-like skin inflammation in mice through inhibition of immune responses and up-regulation of PD-L1 expression

Plasma medicine is an emerging novel therapeutic field. It has been reported that plasma can kill bacteria, promote wound healing and induce apoptosis of tumor cells. However, the effects of plasma on immune cells and immune related skin diseases have not been well studied. In this study, we demonstrated that non-thermal atmospheric plasma (NTP) treatment could inhibit psoriasis-like skin inflammation in mice. NTP treatment in imiquimod-induced psoriasis-like mouse skin inhibited increases in epithelial cell thickness and expression of pro-inflammatory molecules compared to ones without the NTP treatment. In addition, differentiation of Th17 cells, an important cell type for pathogenesis of psoriasis, was inhibited in the NTP-treated mouse lymph nodes. It was also demonstrated that liquid type plasma (LTP), which is also known as indirect plasma, inhibited Th17 cell differentiation in vitro. Other in vitro experiments showed that LTP inhibited bone marrow-derived dendritic cell activation. Interestingly, LTP enhanced PD-L1 expression in HaCaT cells, suggesting that NTP may inhibit unwanted over-activation of T cells through increased PD-L1 expression. Taken together, these results suggest that NTP may be used in treatment of CD4+ T cell-mediated autoimmune diseases such as psoriasis.

Hyperbaric Oxygen Therapy and Oxygen Compatibility of Skin and Wound Care Products

Objective: Use test methods to assess the oxygen compatibility of various wound care products. Approach: There are currently no standard test methods specifically for evaluating the oxygen compatibility and safety of materials under hyperbaric oxygen (HBO) conditions. However, tests such as the oxygen index (OI), oxygen exposure (OE), and autogenous ignition temperature (AIT) can provide useful information. Results: The OI test measures the minimum oxygen concentration that will support candle-like burning, and it was used to test 44 materials. All but two exhibited an OI equal to or greater (safer) than a control material commonly used in HBO. The OE test exposes each material to an oxygen-enriched atmosphere (>99.5% oxygen) to monitor temperature and pressure for an extended duration. The results of the OE testing indicated that none of the 44 articles tested with this method self-ignited within the 60°C, 3 atm pressurized oxygen atmosphere. The AIT test exposes materials to a rapid ramp up in temperature in HBO conditions at 3 atm until ignition occurs. Ten wound care materials and seven materials usually avoided in HBO chambers were tested. The AIT ranged from 138°C to 384°C for wound care products and from 146°C to 420°C for the other materials. Innovation: This work provides useful data and recommendations to help develop a new standard approach for evaluating the HBO compatibility of wound care products to ensure safety for patients and clinicians. Conclusion: The development of an additional test to measure the risk of electrostatic discharge of materials in HBO conditions is needed.

Hyperbaric Oxygen Therapy: Exploring the Clinical Evidence

GENERAL PURPOSE

To provide information about hyperbaric oxygen therapy (HBOT), its mechanisms, indications and safe applications based on clinical evidence.

TARGET AUDIENCE

This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care.

LEARNING OBJECTIVES/OUTCOMES

After participating in this educational activity, the participant should be better able to:1. Recall the physiology of wound healing and the mechanisms of action of HBOT.2. Identify current applications of HBOT based on clinical evidence as well as its risks and contraindications.

ABSTRACT

Treating chronic wounds and infections are challenging medical problems worldwide. Hyperbaric oxygen therapy (HBOT), the administration of 100% oxygen at pressures greater than 1.4 atmosphere absolute in a series of treatments, can be used as an adjunctive therapy in many wound care settings because it improves oxygenation and neovascularization and decreases inflammation in chronic wounds. A growing number of studies support the benefits of HBOT for enhancing wound healing and decreasing the likelihood of negative events such as amputation. However, many practitioners are unfamiliar with HBOT. This article provides a general introduction to HBOT, reviews the physiology and mechanisms of behind HBOT, discusses all the indications for HBOT, and explores in-depth the clinical evidence for HBOT in the treatment of arterial insufficiencies, diabetic ulcers, delayed radiation injury, and chronic refractory osteomyelitis.

Topical Administration of Oxygenated Hemoglobin Improved Wound Healing in an Ischemic Rabbit Ear Model

BACKGROUND

Localized oxygen deficiency plays a central role in the pathogenesis of chronic wounds; thus, rectifying localized ischemia with oxygen therapy has been postulated to be an integral aspect of the management of chronic wounds. The efficacy of a novel approach for oxygen therapy on chronic wound healing was evaluated.

METHODS

Oxygen was delivered to ischemic wounds by means of the topical application of oxygenated, chemically modified bovine hemoglobin (IKOR 2084) in a validated rabbit ear ischemic wound model. The wound healing was evaluated histologically by measuring epithelial gap and neo-granulation tissue area. In situ expression of endothelial cells (CD31) and proliferative cells (Ki-67) was examined by immunohistochemistry analysis. The mRNA of vascular endothelial growth factor, endothelial nitric oxide synthase, and matrix metalloproteinase-9 was quantified by real-time reverse-transcriptase polymerase chain reaction. The collagen was detected by Sirius red staining.

RESULTS

In comparison with topical application of saline, the administration of oxygenated IKOR 2084 increases wound reepithelialization and formation of neo-granulation tissue in a dose-dependent manner, and cellular proliferation (Ki-67). Conversely, the administration of deoxygenated IKOR 2084 aggravated the ischemic wound healing process. Moreover, the topical administration of oxygenated IKOR 2084 induces angiogenesis as evidenced by concomitant increases in CD31 protein and vascular endothelial growth factor and endothelial nitric oxide synthase mRNA expression in treated wounds. Oxygenated IKOR 2084 administration also increased collagen deposition in wounds, with decreases in the expression of matrix metalloproteinase-9 mRNA.

CONCLUSION

This study suggests that the topical application of oxygenated IKOR 2084 ameliorates the reparative progress of ischemic wounds through enhanced angiogenesis, cellular proliferation, and collagen deposition.

Systemic administration of hemoglobin improves ischemic wound healing

BACKGROUND

Oxygen plays multifaceted roles in wound healing, including effects on cell proliferation, collagen synthesis, angiogenesis, and bacterial killing. Oxygen deficit is a major factor in the pathogenesis of chronic wounds.

MATERIALS AND METHODS

We present a novel mechanism for oxygen delivery to ischemic wounds by systemic administration of an oxygen carrier substitute derived from bovine hemoglobin (IKOR 2084) in our ischemic rabbit ear wound model. The wound healing indexes, including epithelial gap and neo-granulation tissue area, were histologically analyzed. In situ expression of endothelial cells (CD31+) and proliferative cells (Ki-67+) were examined by immunohistochemistry analysis. The messenger RNA expression of collagen I, III, and vascular endothelial growth factor was measured by quantitative RT-PCR. Sirius Red staining was implemented for detection of collagen deposition, and terminal deoxynucleotidyl transferase dUTP nick end labeling analysis was performed to examine dermal cellular apoptosis.

RESULTS

Systemic administration of IKOR 2084 significantly improved oxygen tension of ischemic tissue. When compared with saline controls, IKOR 2084 treatment enhanced wound repair as demonstrated by a reduced epithelial gap and increased granulation tissue area. The expression of Ki-67+, CD31+, vascular endothelial growth factor and collagen was also enhanced by IKOR 2084 administration. Moreover, apoptosis analysis in the wounds showed that cell survival in the dermis was increased by systemic IKOR 2084 administration.

CONCLUSIONS

Our study suggests that systemic delivery of IKOR 2084 ameliorates hypoxic state, subsequently promotes angiogenesis, cellular proliferation, and collagen synthesis, attenuates hypoxia-induced apoptosis, and improved ischemic wound healing.

Reactive oxygen species prevent imiquimod-induced psoriatic dermatitis through enhancing regulatory T cell function

Psoriasis is a chronic inflammatory skin disease resulting from immune dysregulation. Regulatory T cells (Tregs) are important in the prevention of psoriasis. Traditionally, reactive oxygen species (ROS) are known to be implicated in the progression of inflammatory diseases, including psoriasis, but many recent studies suggested the protective role of ROS in immune-mediated diseases. In particular, severe cases of psoriasis vulgaris have been reported to be successfully treated by hyperbaric oxygen therapy (HBOT), which raises tissue level of ROS. Also it was reported that Treg function was closely associated with ROS level. However, it has been only investigated in lowered levels of ROS so far. Thus, in this study, to clarify the relationship between ROS level and Treg function, as well as their role in the pathogenesis of psoriasis, we investigated imiquimod-induced psoriatic dermatitis (PD) in association with Treg function both in elevated and lowered levels of ROS by using knockout mice, such as glutathione peroxidase-1^−/− and neutrophil cytosolic factor-1^−/− mice, as well as by using HBOT or chemicals, such as 2,3-dimethoxy-1,4-naphthoquinone and N-acetylcysteine. The results consistently showed Tregs were hyperfunctional in elevated levels of ROS, whereas hypofunctional in lowered levels of ROS. In addition, imiquimod-induced PD was attenuated in elevated levels of ROS, whereas aggravated in lowered levels of ROS. For the molecular mechanism that may link ROS level and Treg function, we investigated the expression of an immunoregulatory enzyme, indoleamine 2,3-dioxygenase (IDO) which is induced by ROS, in PD lesions. Taken together, it was implied that appropriately elevated levels of ROS might prevent psoriasis through enhancing IDO expression and Treg function.

Eczematous reactions due to angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers

Cutaneous adverse drug reactions (ADRs) to antihypertensive drugs have been frequently reported. We describe a peculiar clinical pattern of cutaneous ADR, represented by an eczematous reaction induced by certain antihypertensive drugs that we observed in elderly patients. The case series consisted of 23 hypertensive patients aged 66-87 years; 19 of them were taking another drug in addition to the suspected antihypertensive medication and 15 were on polytherapy with three or more drugs to treat multiple comorbidities. The antihypertensive culprit agents were angiotensin-converting enzyme (ACE) inhibitors in 9 patients, ACE-inhibitors combined to hydrochlorothiazide (HCT) in 7 subjects, angiotensin II receptor blockers alone in 2 patients and associated with HCT in 5 cases. The cutaneous ADR was characterized by an eczematous rash that was generalized in 16 patients and localized in 7 cases, with predominant involvement of lower limbs. Such lesions developed after a latency of 4-30 months and were associated with moderate-to-severe itch, usually unresponsive to oral antihistamines. Histopathological diagnosis was available for 9 cases, confirming the presence of a spongiotic dermatitis with possible associated psoriasiform skin changes.