Immersion in CO2-rich water containing NaCl diminishes blood pressure fluctuation in anesthetized rats

Exposure of Primary Human Skin Fibroblasts to Carbon Dioxide-Containing Solution Significantly Reduces TGF-β-Induced Myofibroblast Differentiation In Vitro

Wound healing as a result of a skin injury involves a series of dynamic physiological processes, leading to wound closure, re-epithelialization, and the remodeling of the extracellular matrix (ECM). The primary scar formed by the new ECM never fully regains the original tissue's strength or flexibility. Moreover, in some cases, due to dysregulated fibroblast activity, proliferation, and differentiation, the normal scarring can be replaced by pathological fibrotic tissue, leading to hypertrophic scars or keloids. These disorders can cause significant physical impairment and psychological stress and represent significant challenges in medical management in the wound-healing process. The present study aimed to investigate the therapeutic effects of exogenously applied carbon dioxide (CO2) on fibroblast behavior, focusing on viability, proliferation, migration, and differentiation to myofibroblasts. We found that CO2 exposure for up to 60 min did not significantly affect fibroblast viability, apoptosis rate, or proliferation and migration capacities. However, a notable finding was the significant reduction in α-smooth muscle actin (α-SMA) protein expression, indicative of myofibroblast differentiation inhibition, following CO2 exposure. This effect was specific to CO2 and concentration as well as time-dependent, with longer exposure durations leading to greater reductions in α-SMA expression. Furthermore, the inhibition of myofibroblast differentiation correlated with a statistically significantly reduced glycolytic and mitochondrial energy metabolism, and as a result, with a reduced ATP synthesis rate. This very noticeable decrease in cellular energy levels seemed to be specific to CO2 exposure and could not be observed in the control cultures using nitrogen (N2)-saturated solutions, indicating a unique and hypoxia-independent effect of CO2 on fibroblast metabolism. These findings suggest that exogenously applied CO2 may possess fibroblast differentiation-reducing properties by modulating fibroblast's energy metabolism and could offer new therapeutic options in the prevention of scar and keloid development.

Local application of a transcutaneous carbon dioxide paste prevents excessive scarring and promotes muscle regeneration in a bupivacaine-induced rat model of muscle injury

In postoperative patients with head and neck cancer, scar tissue formation may interfere with the healing process, resulting in incomplete functional recovery and a reduced quality of life. Percutaneous application of carbon dioxide (CO₂ ) has been reported to improve hypoxia, stimulate angiogenesis, and promote fracture repair and muscle damage. However, gaseous CO₂ cannot be applied to the head and neck regions. Previously, we developed a paste that holds non-gaseous CO₂ in a carrier and can be administered transdermally. Here, we investigated whether this paste could prevent excessive scarring and promote muscle regeneration using a bupivacaine-induced rat model of muscle injury. Forty-eight Sprague Dawley rats were randomly assigned to either a control group or a CO₂ group. Both groups underwent surgery to induce muscle injury, but the control group received no treatment, whereas the CO₂ group received the CO₂ paste daily after surgery. Then, samples of the experimental sites were taken on days 3, 7, 14, and 21 post-surgery to examine the following: (1) inflammatory (interleukin [IL]-1β, IL-6), and transforming growth factor (TGF)-β and myogenic (MyoD and myogenin) gene expression by polymerase chain reaction, (2) muscle regeneration with haematoxylin and eosin staining, and (3) MyoD and myogenin protein expression using immunohistochemical staining. Rats in the CO₂ group showed higher MyoD and myogenin expression and lower IL-1β, IL-6, and TGF-β expression than the control rats. In addition, treated rats showed evidence of accelerated muscle regeneration. Our study demonstrated that the CO₂ paste prevents excessive scarring and accelerates muscle regeneration. This action may be exerted through the induction of an artificial Bohr effect, which leads to the upregulation of MyoD and myogenin, and the downregulation of IL-1β, IL-6, and TGF-β. The paste is inexpensive and non-invasive. Thus, it may be the treatment of choice for patients with muscle damage.

Local Application of Transcutaneous Carbon Dioxide Paste Decreases Inflammation and Accelerates Wound Healing

INTRODUCTION

 Delayed wound healing after surgery lowers the long-term quality of a patient's life and leads to discomfort and pain. However, treatments for wound healing are often difficult and have not yet been fully established. In this study, we investigated the effect of a special paste that can be administered transdermally and holds a non-gaseous carbon dioxide (CO₂) source in its carrier, which can be applied to the head and neck region for wound healing in a rat skin defect model.

METHODS

Forty-eight Sprague Dawley rats were randomized into control and CO₂ groups. We punched a 6.2-mm wound on the back of each rat. The control rats were left untreated, whereas rats in the CO₂ group were treated with the CO₂ paste every day after surgery. We evaluated wound healing 3, 7, 14, and 21 days after wounding by analyzing the diameter of the wound, gene expression of inflammatory markers vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-β, hypoxia-inducible factor (HIF)-1α, interleukin (IL)-1β, and IL-6 using quantitative real-time polymerase chain reaction, hematoxylin and eosin, and immunohistochemical staining patterns.

RESULTS

Rats in the CO₂ group showed accelerated wound healing compared to those in the control group. Furthermore, VEGF and TGF-β were overexpressed, whereas HIF-1α, IL-1β, and IL-6 were downregulated in the rats treated with CO₂. Immunohistochemical analysis also revealed similar patterns of expression.

CONCLUSION

Taken together, the CO₂ paste promoted wound healing by regulating the hypoxic environment, reducing inflammation, and accelerating angiogenesis.

Technological opportunities for sensing of the health effects of weather and climate change: a state-of-the-art-review

Sensing and measuring meteorological and physiological parameters of humans, animals, and plants are necessary to understand the complex interactions that occur between atmospheric processes and the health of the living organisms. Advanced sensing technologies have provided both meteorological and biological data across increasingly vast spatial, spectral, temporal, and thematic scales. Information and communication technologies have reduced barriers to data dissemination, enabling the circulation of information across different jurisdictions and disciplines. Due to the advancement and rapid dissemination of these technologies, a review of the opportunities for sensing the health effects of weather and climate change is necessary. This paper provides such an overview by focusing on existing and emerging technologies and their opportunities and challenges for studying the health effects of weather and climate change on humans, animals, and plants.

Topical cutaneous application of CO2 accelerates bone healing in a rat femoral defect model

BACKGROUND

Bone defects may occur because of severe trauma, nonunion, infection, or tumor resection. However, treatments for bone defects are often difficult and have not been fully established yet. We previously designed an efficient system of topical cutaneous application of carbon dioxide (CO₂) using a novel hydrogel, which facilitates CO₂ absorption through the skin into the deep area within a limb. In this study, the effect of topical cutaneous application of CO₂ on bone healing was investigated using a rat femoral defect model.

METHODS

In this basic research study, an in vivo bone defect model, fixed with an external fixator, was created using a rat femur. The affected limb was shaved, and CO₂ was applied for 20 min/day, 5 days/week. In the control animals, CO₂ gas was replaced with air. Radiographic, histological, biomechanical, and genetic assessments were performed to evaluate bone healing.

RESULTS

Radiographically, bone healing rate was significantly higher in the CO₂ group than in the control group at 4 weeks (18.2% vs. 72.7%). The degree of bone healing scored using the histopathological Allen grading system was significantly higher in the CO₂ group than in the control group at 2 weeks (1.389 ± 0.334 vs. 1.944 ± 0.375). The ultimate stress, extrinsic stiffness, and failure energy were significantly greater in the CO₂ group than in the control group at 4 weeks (3.2 ± 0.8% vs. 38.1 ± 4.8%, 0.6 ± 0.3% vs. 41.5 ± 12.2%, 2.6 ± 0.8% vs. 24.7 ± 5.9%, respectively.). The volumetric bone mineral density of the callus in micro-computed tomography analysis was significantly higher in the CO₂ group than in the control group at 4 weeks (180.9 ± 43.0 mg/cm³ vs. 247.9 ± 49.9 mg/cm³). Gene expression of vascular endothelial growth factor in the CO₂ group was significantly greater than that in the control group at 3 weeks (0.617 ± 0.240 vs. 2.213 ± 0.387).

CONCLUSIONS

Topical cutaneous application of CO₂ accelerated bone healing in a rat femoral defect model. CO₂ application can be a novel and useful therapy for accelerating bone healing in bone defects; further research on its efficacy in humans is warranted.

Bathing in carbon dioxide-enriched water alters protein expression in keratinocytes of skin tissue in rats

Beneficial effects of balneotherapy using naturally occurring carbonated water (CO₂ enriched) have been known since the Middle Ages. Although this therapy is clinically applied for peripheral artery disease and skin disorder, the underlying mechanisms are not fully elucidated.Under controlled conditions, rats were bathed in either CO₂-enriched water (CO₂ content 1200 mg/L) or tap water, both at 37 °C, for 10 min daily over 4 weeks. Proliferation activity was assessed by Ki67 immunohistochemistry of the epidermis of the abdomen. The capillary density was assessed by immunodetection of isolectin-positive cells. Using cryo-fixed abdominal skin epidermis, follicle cells and stroma tissue containing capillaries were separately isolated by means of laser microdissection and subjected to proteomic analysis using label-free technique. Differentially expressed proteins were validated by immunohistochemistry.Proliferation activity of keratinocytes was not significantly different in the epidermis after bathing in CO₂-enriched water, and also, capillary density did not change. Proteomic analysis revealed up to 36 significantly regulated proteins in the analyzed tissue. Based on the best expression profiles, ten proteins were selected for immunohistochemical validation. Only one protein, far upstream element binding protein 2 (FUBP2), was similarly downregulated in the epidermis after bathing in CO₂-enriched water with both techniques. Low FUBP2 expression was associated with low c-Myc immune-expression in keratinocytes.Long-term bathing in CO₂-enriched water showed a cellular protein response of epithelial cells in the epidermis which was detectable by two different methods. However, differences in proliferation activity or capillary density were not detected in the normal skin.

Effect of spa therapy with saline balneotherapy on oxidant/antioxidant status in patients with rheumatoid arthritis: a single-blind randomized controlled trial

Oxidative stress has been shown to play a contributory role in the pathogenesis of rheumatoid arthritis (RA). Recent studies have provided evidence for antioxidant properties of spa therapy. The purpose of this study is to investigate whether spa therapy with saline balneotherapy has any influence on the oxidant/antioxidant status in patients with RA and to assess clinical effects of spa therapy. In this investigator-blind randomized controlled trial, we randomly assigned 50 patients in a 1:1 ratio to spa therapy plus standard drug treatment (spa group) or standard drug treatment alone (control group). Spa group followed a 2-week course of spa therapy regimen consisting of a total of 12 balneotherapy sessions in a thermal mineral water pool at 36-37 °C for 20 min every day except Sunday. All clinical and biochemical parameters were assessed at baseline and after spa therapy (2 weeks). The clinical parameters were pain intensity, patient global assessment, physician global assessment, Health Assessment Questionnaire disability index (HAQ-DI), Disease Activity Score for 28-joints based on erythrocyte sedimentation rate (DAS28-4[ESR]). Oxidative status parameters were malondialdehyde (MDA), nonenzymatic superoxide radical scavenger activity (NSSA), antioxidant potential (AOP), and superoxide dismutase (SOD). The NSSA levels were increased significantly in the spa group (p = 0.003) but not in the control group (p = 0.509); and there was a trend in favor of spa therapy for improvements in NSSA levels compared to control (p = 0.091). Significant clinical improvement was found in the spa group compared to the control in terms of patient global assessment (p = 0.011), physician global assessment (p = 0.043), function (HAQ-DI) (p = 0.037), disease activity (DAS28-4[ESR]) (0.044) and swollen joint count (0.009), and a trend toward improvement in pain scores (0.057). Spa therapy with saline balneotherapy exerts antioxidant effect in patients with RA as reflected by the increase in NSSA levels after spa therapy; whether this antioxidant effect contributes to the clinical improvements observed remains to be verified.

Acute effects of a single warm-water bath on serum adiponectin and leptin levels in healthy men: a pilot study

To preliminarily assess the acute effects of a single warm-water bath (WWB) on serum adipokine activity, we measured serum adiponectin, leptin and other metabolic profiles before, immediately after and 30 minutes after WWB in seven healthy male volunteers (mean age, 39.7 ± 6.0 years; mean body mass index, 21.6 ± 1.8 kg/m(2)). The subjects were immersed in tap water at 41°C for 10 minutes. Two weeks later, the same subjects underwent a single WWB with a bath additive that included inorganic salts and carbon dioxide (WWB with ISCO(2)) by the same protocol as for the first WWB. Leptin levels significantly increased immediately after WWB with tap water and ISCO(2) (both P < 0.05), and remained significantly higher than those at baseline even 30 minutes after WWB with tap water (P < 0.05). Adiponectin levels showed a slight, but not significant, increase both immediately after and 30 minutes after WWB with tap water or ISCO(2). Some parameters, such as serum total cholesterol, red blood cell count, hemoglobin and hematocrit significantly increased immediately after WWB with tap water or ISCO(2) (all P < 0.05), but they all returned to the baseline levels 30 minutes after bathing under both conditions. The sublingual temperature rose significantly after 10 minutes of WWB with tap water (0.96 ± 0.16°C relative to baseline, P < 0.01) and after the same duration of WWB with ISCO(2) (1.24 ± 0.34°C relative to baseline, P < 0.01). These findings suggest that a single WWB at 41°C for 10 minutes may modulate leptin and adiponectin profiles in healthy men.

A novel system for transcutaneous application of carbon dioxide causing an "artificial Bohr effect" in the human body

Background

Carbon dioxide (CO₂) therapy refers to the transcutaneous administration of CO₂ for therapeutic purposes. This effect has been explained by an increase in the pressure of O₂ in tissues known as the Bohr effect. However, there have been no reports investigating the oxygen dissociation of haemoglobin (Hb) during transcutaneous application of CO₂in vivo. In this study, we investigate whether the Bohr effect is caused by transcutaneous application of CO2 in human living body.

Methods

We used a novel system for transcutaneous application of CO₂ using pure CO₂ gas, hydrogel, and a plastic adaptor. The validity of the CO₂ hydrogel was confirmed in vitro using a measuring device for transcutaneous CO₂ absorption using rat skin. Next, we measured the pH change in the human triceps surae muscle during transcutaneous application of CO₂ using phosphorus-31 magnetic resonance spectroscopy (³¹P-MRS) in vivo. In addition, oxy- and deoxy-Hb concentrations were measured with near-infrared spectroscopy in the human arm with occulted blood flow to investigate O2 dissociation from Hb caused by transcutaneous application of CO₂.

Results

The rat skin experiment showed that CO₂ hydrogel enhanced CO₂ gas permeation through the rat skin. The intracellular pH of the triceps surae muscle decreased significantly 10 min. after transcutaneous application of CO₂. The NIRS data show the oxy-Hb concentration decreased significantly 4 min. after CO₂ application, and deoxy-Hb concentration increased significantly 2 min. after CO₂ application in the CO₂-applied group compared to the control group. Oxy-Hb concentration significantly decreased while deoxy-Hb concentration significantly increased after transcutaneous CO₂ application.

Conclusions

Our novel transcutaneous CO₂ application facilitated an O₂ dissociation from Hb in the human body, thus providing evidence of the Bohr effect in vivo.

Carbon dioxide balneotherapy and cardiovascular disease

Carbon dioxide (CO(2)) balneotherapy is a kind of remedy with a wide spectrum of applications which have been used since the Middle Ages. However, its potential use as an adjuvant therapeutic option in patients with cardiovascular disease is not yet fully clarified. We performed a thorough review of MEDLINE Database, EMBASE, ISI WEB of Knowledge, COCHRANE database and sites funded by balneotherapy centers across Europe in order to recognize relevant studies and aggregate evidence supporting the use of CO(2) baths in various cardiovascular diseases. The three main effects of CO(2) hydrotherapy during whole body or partial immersion, including decline in core temperature, an increase in cutaneous blood flow, and an elevation of the score on thermal sensation, are analyzed on a pathophysiology basis. Additionally, the indications and contra-indications of the method are presented in an evidence-based way, while the need for new methodologically sufficient studies examining the use of CO(2) baths in other cardiovascular substrates is discussed.

Crenotherapy: a neglected resource for human health now re-emerging on sound scientific concepts

Recent mechanistic evidence demonstrates that spa-based therapy (or, as we propose, crenotherapy from the Greek word kapparhoepsilonnueta, spring fountain) is indeed based on solid scientific data. This mini-review highlights the latest insights into the mechanisms of crenotherapy derived from in vitro experiments, studies on animal models, and carefully designed clinical trials. Although more basic and clinical data are still needed, crenotherapy is coming of age as a modern, scientifically sound therapy. As the underlying mechanisms are uncovered, it is becoming possible to choose the most appropriate applications of this centuries-old practice, possibly reducing medical costs, thus explaining the current worldwide renewed interest in crenotherapy.