1
|
Vezzoli A, Mrakic-Sposta S, Brizzolari A, Balestra C, Camporesi EM, Bosco G. Oxy-Inflammation in Humans during Underwater Activities. Int J Mol Sci 2024; 25:3060. [PMID: 38474303 DOI: 10.3390/ijms25053060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 02/22/2024] [Accepted: 03/01/2024] [Indexed: 03/14/2024] Open
Abstract
Underwater activities are characterized by an imbalance between reactive oxygen/nitrogen species (RONS) and antioxidant mechanisms, which can be associated with an inflammatory response, depending on O2 availability. This review explores the oxidative stress mechanisms and related inflammation status (Oxy-Inflammation) in underwater activities such as breath-hold (BH) diving, Self-Contained Underwater Breathing Apparatus (SCUBA) and Closed-Circuit Rebreather (CCR) diving, and saturation diving. Divers are exposed to hypoxic and hyperoxic conditions, amplified by environmental conditions, hyperbaric pressure, cold water, different types of breathing gases, and air/non-air mixtures. The "diving response", including physiological adaptation, cardiovascular stress, increased arterial blood pressure, peripheral vasoconstriction, altered blood gas values, and risk of bubble formation during decompression, are reported.
Collapse
Affiliation(s)
- Alessandra Vezzoli
- Institute of Clinical Physiology-National Research Council (CNR-IFC), 20142 Milano, Italy
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
| | - Simona Mrakic-Sposta
- Institute of Clinical Physiology-National Research Council (CNR-IFC), 20142 Milano, Italy
| | - Andrea Brizzolari
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
| | - Costantino Balestra
- Environmental, Occupational, Aging (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), 1160 Brussels, Belgium
- Physical Activity Teaching Unit, Motor Sciences Department, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
- DAN Europe Research Division (Roseto-Brussels), 1160 Brussels, Belgium
| | | | - Gerardo Bosco
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
| |
Collapse
|
2
|
Fan JF, Wang YK, Liu M, Liu GS, Min TJ, Chen RY, He Y. Effect of angiotensin II on irradiation exacerbated decompression sickness. Sci Rep 2023; 13:11659. [PMID: 37468556 DOI: 10.1038/s41598-023-38752-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 07/14/2023] [Indexed: 07/21/2023] Open
Abstract
In some complicated situations, decompression sickness (DCS) combined with other injuries, such as irradiation, will seriously endanger life safety. However, it is still unclear whether irradiation will increase the incidence of DCS. This study was designed to investigate the damage effects of irradiation on decompression injury and the underlying mechanism. Sprague-Dawley rats were exposed to irradiation followed by hyperbaric decompressing and the mortality and decompression symptoms were observed. Lung tissue and bronchoalveolar lavage fluid were collected to detect the lung lesion, inflammation response, activity of the angiotensin system, oxidative stress, and relative signal pathway by multiple methods, including Q-PCR, western blot, and ELISA. As a result, pre-exposure to radiation significantly exacerbated disease outcomes and lung lesions of DCS. Mechanically, the up-regulation of angiotensin-converting enzyme expression and angiotensin II levels was responsible for the exacerbated DCS and lung lesions caused by predisposing irradiation exposure. Oxidative stress and PI3K/AKT signal pathway activation in pulmonary tissue were enhanced after irradiation plus decompression treatment. In conclusion, our results suggested that irradiation could exacerbate lung injury and the outcomes of DCS by activating the angiotensin system, which included eliciting oxidative stress and activation of the PI3K/AKT signal pathway.
Collapse
Affiliation(s)
- Jie-Fu Fan
- Naval Medical Center of PLA, Naval Medical University (Second Military Medical University), Shanghai, China
| | - Yang-Kai Wang
- Naval Medical Center of PLA, Naval Medical University (Second Military Medical University), Shanghai, China
| | - Min Liu
- Naval Medical Center of PLA, Naval Medical University (Second Military Medical University), Shanghai, China
| | - Guang-Sheng Liu
- Naval Medical Center of PLA, Naval Medical University (Second Military Medical University), Shanghai, China
| | - Tian-Jiao Min
- Naval Medical Center of PLA, Naval Medical University (Second Military Medical University), Shanghai, China
| | - Rui-Yong Chen
- Naval Medical Center of PLA, Naval Medical University (Second Military Medical University), Shanghai, China.
| | - Ying He
- Naval Medical Center of PLA, Naval Medical University (Second Military Medical University), Shanghai, China.
| |
Collapse
|
3
|
Vascular Function Recovery Following Saturation Diving. Medicina (B Aires) 2022; 58:medicina58101476. [PMID: 36295636 PMCID: PMC9610043 DOI: 10.3390/medicina58101476] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 10/07/2022] [Accepted: 10/13/2022] [Indexed: 11/28/2022] Open
Abstract
Background and Objectives: Saturation diving is a technique used in commercial diving. Decompression sickness (DCS) was the main concern of saturation safety, but procedures have evolved over the last 50 years and DCS has become a rare event. New needs have evolved to evaluate the diving and decompression stress to improve the flexibility of the operations (minimum interval between dives, optimal oxygen levels, etc.). We monitored this stress in saturation divers during actual operations. Materials and Methods: The monitoring included the detection of vascular gas emboli (VGE) and the changes in the vascular function measured by flow mediated dilatation (FMD) after final decompression to surface. Monitoring was performed onboard a diving support vessel operating in the North Sea at typical storage depths of 120 and 136 msw. A total of 49 divers signed an informed consent form and participated to the study. Data were collected on divers at surface, before the saturation and during the 9 h following the end of the final decompression. Results: VGE were detected in three divers at very low levels (insignificant), confirming the improvements achieved on saturation decompression procedures. As expected, the FMD showed an impairment of vascular function immediately at the end of the saturation in all divers but the divers fully recovered from these vascular changes in the next 9 following hours, regardless of the initial decompression starting depth. Conclusion: These changes suggest an oxidative/inflammatory dimension to the diving/decompression stress during saturation that will require further monitoring investigations even if the vascular impairement is found to recover fast.
Collapse
|
4
|
Lambrechts K, Germonpré P, Vandenheede J, Delorme M, Lafère P, Balestra C. Mini Trampoline, a New and Promising Way of SCUBA Diving Preconditioning to Reduce Vascular Gas Emboli? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:5410. [PMID: 35564805 PMCID: PMC9105492 DOI: 10.3390/ijerph19095410] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 04/21/2022] [Accepted: 04/26/2022] [Indexed: 12/31/2022]
Abstract
Background: Despite evolution in decompression algorithms, decompression illness is still an issue nowadays. Reducing vascular gas emboli (VGE) production or preserving endothelial function by other means such as diving preconditioning is of great interest. Several methods have been tried, either mechanical, cardiovascular, desaturation aimed or biochemical, with encouraging results. In this study, we tested mini trampoline (MT) as a preconditioning strategy. Methods: In total, eight (five females, three males; mean age 36 ± 16 years; body mass index 27.5 ± 7.1 kg/m2) healthy, non-smoking, divers participated. Each diver performed two standardized air dives 1 week apart with and without preconditioning, which consisted of ±2 min of MT jumping. All dives were carried out in a pool (NEMO 33, Brussels, Belgium) at a depth of 25 m for 25 min. VGE counting 30 and 60 min post-dive was recorded by echocardiography together with an assessment of endothelial function by flow-mediated dilation (FMD). Results: VGE were significantly reduced after MT (control: 3.1 ± 4.9 VGE per heartbeat vs. MT: 0.6 ± 1.1 VGE per heartbeat, p = 0.031). Post-dive FMD exhibited a significant decrease in the absence of preconditioning (92.9% ± 7.4 of pre-dive values, p = 0.03), as already described. MT preconditioning prevented this FMD decrease (103.3% ± 7.1 of pre-dive values, p = 0.30). FMD difference is significant (p = 0.03). Conclusions: In our experience, MT seems to be a very good preconditioning method to reduce VGE and endothelial changes. It may become the easiest, cheapest and more efficient preconditioning for SCUBA diving.
Collapse
Affiliation(s)
- Kate Lambrechts
- Environmental, Occupational, Aging (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), 1180 Brussels, Belgium; (K.L.); (P.G.); (J.V.); (M.D.); (P.L.)
| | - Peter Germonpré
- Environmental, Occupational, Aging (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), 1180 Brussels, Belgium; (K.L.); (P.G.); (J.V.); (M.D.); (P.L.)
- DAN Europe Research Division (Roseto-Brussels), 1160 Brussels, Belgium
- Centre for Hyperbaric Oxygen Therapy, Queen Astrid Military Hospital, 1120 Brussels, Belgium
| | - Joaquim Vandenheede
- Environmental, Occupational, Aging (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), 1180 Brussels, Belgium; (K.L.); (P.G.); (J.V.); (M.D.); (P.L.)
- Motor Sciences Department, Physical Activity Teaching Unit, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
| | - Manon Delorme
- Environmental, Occupational, Aging (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), 1180 Brussels, Belgium; (K.L.); (P.G.); (J.V.); (M.D.); (P.L.)
| | - Pierre Lafère
- Environmental, Occupational, Aging (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), 1180 Brussels, Belgium; (K.L.); (P.G.); (J.V.); (M.D.); (P.L.)
- DAN Europe Research Division (Roseto-Brussels), 1160 Brussels, Belgium
- Laboratoire ORPHY, EA4324, Université de Bretagne Occidentale (UBO), 29238 Brest, France
| | - Costantino Balestra
- Environmental, Occupational, Aging (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), 1180 Brussels, Belgium; (K.L.); (P.G.); (J.V.); (M.D.); (P.L.)
- DAN Europe Research Division (Roseto-Brussels), 1160 Brussels, Belgium
- Motor Sciences Department, Physical Activity Teaching Unit, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
| |
Collapse
|
5
|
Rosén A, Gennser M, Oscarsson N, Kvarnström A, Sandström G, Seeman-Lodding H, Simrén J, Zetterberg H. Protein tau concentration in blood increases after SCUBA diving: an observational study. Eur J Appl Physiol 2022; 122:993-1005. [PMID: 35142945 PMCID: PMC8926952 DOI: 10.1007/s00421-022-04892-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 01/05/2022] [Indexed: 11/27/2022]
Abstract
Purpose It is speculated that diving might be harmful to the nervous system. The aim of this study was to determine if established markers of neuronal injury were increased in the blood after diving. Methods Thirty-two divers performed two identical dives, 48 h apart, in a water-filled hyperbaric chamber pressurized to an equivalent of 42 m of sea water for 10 min. After one of the two dives, normobaric oxygen was breathed for 30 min, with air breathed after the other. Blood samples were obtained before and at 30–45 and 120 min after diving. Concentrations of glial fibrillary acidic, neurofilament light, and tau proteins were measured using single molecule array technology. Doppler ultrasound was used to detect venous gas emboli. Results Tau was significantly increased at 30–45 min after the second dive (p < 0.0098) and at 120 min after both dives (p < 0.0008/p < 0.0041). Comparison of matching samples showed that oxygen breathing after diving did not influence tau results. There was no correlation between tau concentrations and the presence of venous gas emboli. Glial fibrillary acidic protein was decreased 30–45 min after the first dive but at no other point. Neurofilament light concentrations did not change. Conclusions Tau seems to be a promising marker of dive-related neuronal stress, which is independent of the presence of venous gas emboli. Future studies could validate these results and determine if there is a quantitative relationship between dive exposure and change in tau blood concentration. Supplementary Information The online version contains supplementary material available at 10.1007/s00421-022-04892-9.
Collapse
Affiliation(s)
- Anders Rosén
- Department of Anaesthesia and Intensive Care Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden.
- Department of Anaesthesia and Intensive Care Medicine, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
| | - Mikael Gennser
- Swedish Aerospace Physiology Centre, Division of Environmental Physiology, Department of Biomedical Engineering and Health Systems, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology, KTH, Stockholm, Sweden
| | - Nicklas Oscarsson
- Department of Anaesthesia and Intensive Care Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden
- Department of Anaesthesia and Intensive Care Medicine, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Andreas Kvarnström
- Department of Anaesthesia and Intensive Care Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden
- Department of Anaesthesia and Intensive Care Medicine, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Göran Sandström
- Department of Anaesthesia and Intensive Care Medicine, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Swedish Armed Forces, Center for Defence Medicine, Gothenburg, Sweden
| | - Helen Seeman-Lodding
- Department of Anaesthesia and Intensive Care Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden
- Department of Anaesthesia and Intensive Care Medicine, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Joel Simrén
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Gothenburg, Sweden
- Department of Psychiatry and Neurochemistry, Sahlgrenska Academy, University of Gothenburg, Mölndal, Sweden
| | - Henrik Zetterberg
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Gothenburg, Sweden
- Department of Psychiatry and Neurochemistry, Sahlgrenska Academy, University of Gothenburg, Mölndal, Sweden
- Department of Neurodegenerative Disease, Institute of Neurology, University College London, London, UK
- UK Dementia Research Institute, University College London, London, UK
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong, China
| |
Collapse
|
6
|
Effect of Water Amount Intake before Scuba Diving on the Risk of Decompression Sickness. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18147601. [PMID: 34300051 PMCID: PMC8306992 DOI: 10.3390/ijerph18147601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/09/2021] [Accepted: 07/15/2021] [Indexed: 11/17/2022]
Abstract
Background and objective: The aim of this study was to investigate the influence of pre-hydration levels on circulating bubble formation for scuba divers and to evaluate the appropriate volume of water intake for reducing the risk of decompression sickness (DCS). Materials and Methods: Twenty scuba divers were classified into four groups according to the volume of water taken in before scuba diving as follows: no-water-intake group (NWIG), 30%-water-intake group (30WIG), 50%-water intake group (50WIG), and 100%-water-intake group (100WIG). We measured the circulating bubbles using movement status by Doppler on the right and left subclavian veins and precordial regions at pre-dive, post-dive, and 30 min after diving to a depth of 30 m for a duration of 25 min at the bottom. Results: Participants belonging to the 30WIG showed the lowest frequency, percentage, and amplitude of bubbles and consequently the lowest bubble grade in the left and right subclavian veins and precordial region at post-time and 30 min after diving. Conclusions: It can be inferred that pre-hydration with 30% of the recommended daily water intake before scuba diving effectively suppressed the formation of bubbles after diving and decreased the risk of DCS.
Collapse
|
7
|
Wang Q, Guerrero F, Theron M. Pre-hydration strongly reduces decompression sickness occurrence after a simulated dive in the rat. Diving Hyperb Med 2020; 50:288-291. [PMID: 32957132 PMCID: PMC7819728 DOI: 10.28920/dhm50.3.288-291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 04/12/2020] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Hydration status is considered a parameter likely to influence the risk of decompression sickness (DCS), but scientific evidence is scarce and conflicting. This experiment aimed to analyse the influence of pre-hydration on DCS occurrence in a rat model. METHODS Intra-peritoneal injections of saline solution were administered to rats (NaCl 0.9% 0 ml (Control), 0.1 ml (Group 1), or 1 ml·100g-1 body mass (Group 2) at each of 24 h, 12 h, and 30 min prior to simulated air dives (45 min at 1,010 kPa; compression and decompression rates 101 kPa·min-1; stops 5 min at 202 kPa, 5 min at 160 kPa, 10 min at 130 kPa). Evaluation of DCS occurrence and severity was made after decompression. RESULTS Pre-dive hydration reduced severe DCS from 47% (Control) to 29% (Group 1) and 0% (Group 2), and increased the proportion of animals without any signs of DCS from 40 (Control) to 57% (Group 1) and 93% (Group 2); Chi2 P = 0.041. CONCLUSIONS This experiment demonstrated that pre-hydration can drastically reduce the DCS occurrence in an animal model. In the context of scuba diving, this result highlights the importance of elucidating the mechanisms linking hydration status and DCS risk.
Collapse
Affiliation(s)
- Qiong Wang
- Laboratory ORPHY, European University of Bretagne, University of Brest, Brest, France
| | - François Guerrero
- Laboratory ORPHY, European University of Bretagne, University of Brest, Brest, France
| | - Michaël Theron
- Laboratory ORPHY, European University of Bretagne, University of Brest, Brest, France
- Corresponding author: Dr Michaël Theron, Laboratory ORPHY, European University of Bretagne, University of Brest, 6 Avenue Le Gorgeu, 29238 Brest, France,
| |
Collapse
|
8
|
Lautridou J, Dugrenot E, Amérand A, Guernec A, Pichavant-Rafini K, Goanvec C, Inizan M, Albacete G, Belhomme M, Galinat H, Lafère P, Balestra C, Moisan C, Buzzacott P, Guerrero F. Physiological characteristics associated with increased resistance to decompression sickness in male and female rats. J Appl Physiol (1985) 2020; 129:612-625. [PMID: 32702269 DOI: 10.1152/japplphysiol.00324.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Decompression sickness (DCS) is a complex and poorly understood systemic disease with wide interindividual resistance variability. We selectively bred rats with a threefold greater resistance to DCS than standard ones. To investigate possible physiological mechanisms underlying the resistance to DCS, including sex-related differences in these mechanisms, 15 males and 15 females resistant to DCS were compared with aged-matched standard Wistar males (n = 15) and females (n = 15). None of these individuals had been previously exposed to hyperbaric treatment. Comparison of the allelic frequencies of single nucleotide polymorphisms (SNPs) showed a difference of one SNP located on the X chromosome. Compared with nonresistant rats, the neutrophil-to-lymphocyte ratio and the plasmatic activity of coagulation factor X were significantly higher in DCS-resistant individuals regardless of their sex. The maximal relaxation elicited by sodium nitroprusside was lower in DCS-resistant individuals regardless of their sex. Males but not females resistant to DCS exhibited higher neutrophil and lymphocyte counts and higher prothrombin time but lower mitochondrial basal O2 consumption and citrate synthase activity. Principal components analysis showed that two principal components discriminate the DCS-resistant males but not females from the nonresistant ones. These components were loaded with activated partial thromboplastin time, monocyte-to-lymphocyte ratio, prothrombin time, factor X, and fibrinogen for PC1 and red blood cells count and neutrophils count for PC2. In conclusion, the mechanisms that drive the resistance to DCS appear different between males and females; lower coagulation tendency and enhanced inflammatory response to decompression stress might be key for resistance in males. The involvement of these physiological adaptations in resistance to DCS must now be confirmed.NEW & NOTEWORTHY By selective breeding of individuals resistant to decompression sickness (DCS) we previously obtained a rat model of inherited resistance to this pathology. Comparison of these individuals with nonresistant animals revealed differences in leukocyte counts, coagulation, and mitochondrial and vascular functions, but not resistance to oxidative stress. This study also reveals sex-related differences in the physiological changes associated with DCS resistance. A principal components analysis of our data allowed us to discriminate DCS-resistant males from standard ones, but not females. These differences represent possible mechanisms driving resistance to DCS. Although still far from the diver, this opens a pathway to future adaptation of personalized decompression procedures for "DCS-prone" individuals.
Collapse
Affiliation(s)
| | - Emmanuel Dugrenot
- University of Brest, ORPHY, IBSAM, Brest, France.,TEK Diving, Brest, France
| | | | | | | | | | - Manon Inizan
- University of Brest, ORPHY, IBSAM, Brest, France
| | | | | | - Hubert Galinat
- Hematology Laboratory, CHRU Cavale Blanche, Brest, France
| | - Pierre Lafère
- University of Brest, ORPHY, IBSAM, Brest, France.,DAN Europe Research Division, Brussels, Belgium
| | - Costantino Balestra
- Environmental & Occupational Physiology Laboratory, Haute Ecole Bruxelles-Brabant, Brussels, Belgium.,DAN Europe Research Division, Brussels, Belgium
| | | | - Peter Buzzacott
- School of Nursing, Midwifery and Paramedicine, Curtin University, Perth, Australia
| | | |
Collapse
|
9
|
Honěk J, Šrámek M, Šefc L, Januška J, Fiedler J, Horváth M, Tomek A, Novotný Š, Honěk T, Veselka J. High-grade patent foramen ovale is a risk factor of unprovoked decompression sickness in recreational divers. J Cardiol 2019; 74:519-523. [PMID: 31255461 DOI: 10.1016/j.jjcc.2019.04.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 03/20/2019] [Accepted: 04/28/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND Patent foramen ovale (PFO), male sex, age, and body mass index (BMI) were all identified as potential risk factors of decompression sickness (DCS). It has been debated whether PFO might cause unprovoked DCS (i.e. without violation of decompression procedure) due to paradoxical embolization of venous gas emboli. To date, there are no data on the incidence or risk factors of unprovoked DCS. This study sought to evaluate the risk factors of unprovoked DCS in recreational divers. METHODS A total of 489 consecutive divers were screened for PFO between January 2006 and January 2014 by means of transcranial Doppler. All patients were prospectively included in the study registry. Survival analysis techniques were used to assess for risk factors for unprovoked DCS. Age, sex, BMI, PFO presence, and grade were analyzed. The total sum of dives was used as a measure of time. RESULTS The group performed a total of 169,411 dives (mean 346±636). Thirty-six (7%) of the divers suffered from an unprovoked DCS. The frequency of PFO was 97.2% in divers with a history of unprovoked DCS and 35.5% in controls (p<0.001). There was no difference in sex, age, BMI, or total number of dives between the respective groups. In the adjusted Cox proportional hazards model, PFO grade 3 was a major risk factor for unprovoked DCS; there was a slight protective effect of increasing age. CONCLUSIONS We demonstrated that a high-grade PFO was a major risk factor for unprovoked DCS in recreational scuba divers.
Collapse
Affiliation(s)
- Jakub Honěk
- Department of Cardiology, Charles University in Prague, 2nd Faculty of Medicine and Motol University Hospital, Prague, Czech Republic; Center for Advanced Preclinical Imaging, Charles University in Prague, First Faculty of Medicine, Prague, Czech Republic.
| | - Martin Šrámek
- Center for Advanced Preclinical Imaging, Charles University in Prague, First Faculty of Medicine, Prague, Czech Republic; Department of Neurology, Charles University in Prague, 2nd Faculty of Medicine and Motol University Hospital, Prague, Czech Republic; Comprehensive Stroke Center, Military University Hospital, Prague, Czech Republic
| | - Luděk Šefc
- Center for Advanced Preclinical Imaging, Charles University in Prague, First Faculty of Medicine, Prague, Czech Republic
| | | | - Jiří Fiedler
- Department of Cardiology, Charles University in Prague, 2nd Faculty of Medicine and Motol University Hospital, Prague, Czech Republic
| | - Martin Horváth
- Department of Cardiology, Charles University in Prague, 2nd Faculty of Medicine and Motol University Hospital, Prague, Czech Republic
| | - Aleš Tomek
- Department of Neurology, Charles University in Prague, 2nd Faculty of Medicine and Motol University Hospital, Prague, Czech Republic
| | - Štěpán Novotný
- Hyperbaric Chamber, Kladno Regional Hospital, Kladno, Czech Republic
| | - Tomáš Honěk
- Department of Cardiology, Charles University in Prague, 2nd Faculty of Medicine and Motol University Hospital, Prague, Czech Republic
| | - Josef Veselka
- Department of Cardiology, Charles University in Prague, 2nd Faculty of Medicine and Motol University Hospital, Prague, Czech Republic
| |
Collapse
|
10
|
Balestra C, Germonpré P, Rocco M, Biancofiore G, Kot J. Diving physiopathology: the end of certainties? Food for thought. Minerva Anestesiol 2019; 85:1129-1137. [PMID: 31238641 DOI: 10.23736/s0375-9393.19.13618-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Our understanding of decompression physiopathology has slowly improved during this last decade and some uncertainties have disappeared. A better understanding of anatomy and functional aspects of patent foramen ovale (PFO) have slowly resulted in a more liberal approach toward the medical fitness to dive for those bearing a PFO. Circulating vascular gas emboli (VGE) are considered the key actors in development of decompression sickness and can be considered as markers of decompression stress indicating induction of pathophysiological processes not necessarily leading to occurrence of disease symptoms. During the last decade, it has appeared possible to influence post-dive VGE by a so-called "preconditioning" as a pre-dive denitrogenation, exercise or some pharmacological agents. In the text we have deeply examined all the scientific evidence about this complicated but challenging theme. Finally, the role of the "normobaric oxygen paradox" has been clarified and it is not surprising that it could be involved in neuroprotection and cardioprotection. However, the best level of inspired oxygen and the exact time frame to achieve optimal effect is still not known. The aim of this paper was to reflect upon the most actual uncertainties and distil out of them a coherent, balanced advice towards the researchers involved in gas-bubbles-related pathologies.
Collapse
Affiliation(s)
- Costantino Balestra
- Laboratory of Environmental and Occupational (Integrative) Physiology, Haute Ecole Bruxelles-Brabant, Auderghem, Brussels, Belgium.,Division of Research, Divers Alert Network Europe, Gharghur, Malta
| | - Peter Germonpré
- Laboratory of Environmental and Occupational (Integrative) Physiology, Haute Ecole Bruxelles-Brabant, Auderghem, Brussels, Belgium.,Division of Research, Divers Alert Network Europe, Gharghur, Malta.,Center for Hyperbaric Oxygen Therapy, Military Hospital of Brussels, Brussels, Belgium
| | - Monica Rocco
- Unit of Intensive Care, Department of Surgical and Medical Science and Translational Medicine, Sapienza University, Rome, Italy -
| | | | - Jacek Kot
- National Center of Hyperbaric Medicine in Gdynia, Medical University of Gdansk, Gdansk, Poland
| |
Collapse
|
11
|
|
12
|
Blatteau JE, Gaillard S, De Maistre S, Richard S, Louges P, Gempp E, Druelles A, Lehot H, Morin J, Castagna O, Abraini JH, Risso JJ, Vallée N. Reduction in the Level of Plasma Mitochondrial DNA in Human Diving, Followed by an Increase in the Event of an Accident. Front Physiol 2018; 9:1695. [PMID: 30555340 PMCID: PMC6282000 DOI: 10.3389/fphys.2018.01695] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 11/09/2018] [Indexed: 01/02/2023] Open
Abstract
Circulating mitochondrial DNA (mtDNA) is receiving increasing attention as a danger-associated molecular pattern in conditions such as autoimmunity or trauma. In the context of decompression sickness (DCS), the course of which is sometimes erratic, we hypothesize that mtDNA plays a not insignificant role particularly in neurological type accidents. This study is based on the comparison of circulating mtDNA levels in humans presenting with various types of diving accidents, and punctured upon their admission at the hyperbaric facility. One hundred and fourteen volunteers took part in the study. According to the clinical criteria there were 12 Cerebro DCS, 57 Medullary DCS, 15 Vestibular DCS, 8 Ctrl+ (accident-free divers), and 22 Ctrl- (non-divers). This work demonstrates that accident-free divers have less mtDNA than non-divers, which leads to the assumption that hyperbaric exposure degrades the mtDNA. mtDNA levels are on average greater in divers with DCS compared with accident-free divers. On another hand, the amount of double strand DNA (dsDNA) is neither significantly different between controls, nor between the different DCS types. Initially the increase in circulating oligonucleotides was attributed to the destruction of cells by bubble abrasion following necrotic phenomena. If there really is a significant difference between the Medullary DCS and the Ctrl-, this difference is not significant between these same DCS and the Ctrl+. This refutes the idea of massive degassing and suggests the need for new research in order to verify that oxidative stress could be a key element without necessarily being sufficient for the occurrence of a neurological type of accident.
Collapse
Affiliation(s)
- Jean-Eric Blatteau
- Institut de Recherche Biomédicale des Armées, Equipe Résidante de Recherche Subaquatique Opérationnelle, Département Environnement Opérationnel, Unité Environnements Extrêmes, Toulon, France
- Hôpital d’Instruction des Armées – Service de Médecine Hyperbare et Expertise Plongée, Toulon, France
| | | | - Sébastien De Maistre
- Hôpital d’Instruction des Armées – Service de Médecine Hyperbare et Expertise Plongée, Toulon, France
| | - Simone Richard
- Mediterranean Institute of Oceanography, Université de Toulon, Toulon, France
| | - Pierre Louges
- Hôpital d’Instruction des Armées – Service de Médecine Hyperbare et Expertise Plongée, Toulon, France
| | - Emmanuel Gempp
- Hôpital d’Instruction des Armées – Service de Médecine Hyperbare et Expertise Plongée, Toulon, France
| | - Arnaud Druelles
- Hôpital d’Instruction des Armées – Service de Médecine Hyperbare et Expertise Plongée, Toulon, France
| | - Henri Lehot
- Hôpital d’Instruction des Armées – Service de Médecine Hyperbare et Expertise Plongée, Toulon, France
| | - Jean Morin
- Hôpital d’Instruction des Armées – Service de Médecine Hyperbare et Expertise Plongée, Toulon, France
| | - Olivier Castagna
- Institut de Recherche Biomédicale des Armées, Equipe Résidante de Recherche Subaquatique Opérationnelle, Département Environnement Opérationnel, Unité Environnements Extrêmes, Toulon, France
| | - Jacques H. Abraini
- Institut de Recherche Biomédicale des Armées, Equipe Résidante de Recherche Subaquatique Opérationnelle, Département Environnement Opérationnel, Unité Environnements Extrêmes, Toulon, France
| | - Jean-Jacques Risso
- Institut de Recherche Biomédicale des Armées, Equipe Résidante de Recherche Subaquatique Opérationnelle, Département Environnement Opérationnel, Unité Environnements Extrêmes, Toulon, France
| | - Nicolas Vallée
- Institut de Recherche Biomédicale des Armées, Equipe Résidante de Recherche Subaquatique Opérationnelle, Département Environnement Opérationnel, Unité Environnements Extrêmes, Toulon, France
| |
Collapse
|
13
|
Venous gas emboli are involved in post-dive macro, but not microvascular dysfunction. Eur J Appl Physiol 2017; 117:335-344. [DOI: 10.1007/s00421-017-3537-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Accepted: 01/03/2017] [Indexed: 10/20/2022]
|
14
|
Balestra C, Theunissen S, Papadopoulou V, Le Mener C, Germonpré P, Guerrero F, Lafère P. Pre-dive Whole-Body Vibration Better Reduces Decompression-Induced Vascular Gas Emboli than Oxygenation or a Combination of Both. Front Physiol 2016; 7:586. [PMID: 27965591 PMCID: PMC5127795 DOI: 10.3389/fphys.2016.00586] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Accepted: 11/14/2016] [Indexed: 11/13/2022] Open
Abstract
Purpose: Since non-provocative dive profiles are no guarantor of protection against decompression sickness, novel means including pre-dive "preconditioning" interventions, are proposed for its prevention. This study investigated and compared the effect of pre-dive oxygenation, pre-dive whole body vibration or a combination of both on post-dive bubble formation. Methods: Six healthy volunteers performed 6 no-decompression dives each, to a depth of 33 mfw for 20 min (3 control dives without preconditioning and 1 of each preconditioning protocol) with a minimum interval of 1 week between each dive. Post-dive bubbles were counted in the precordium by two-dimensional echocardiography, 30 and 90 min after the dive, with and without knee flexing. Each diver served as his own control. Results: Vascular gas emboli (VGE) were systematically observed before and after knee flexing at each post-dive measurement. Compared to the control dives, we observed a decrease in VGE count of 23.8 ± 7.4% after oxygen breathing (p < 0.05), 84.1 ± 5.6% after vibration (p < 0.001), and 55.1 ± 9.6% after vibration combined with oxygen (p < 0.001). The difference between all preconditioning methods was statistically significant. Conclusions: The precise mechanism that induces the decrease in post-dive VGE and thus makes the diver more resistant to decompression stress is still not known. However, it seems that a pre-dive mechanical reduction of existing gas nuclei might best explain the beneficial effects of this strategy. The apparent non-synergic effect of oxygen and vibration has probably to be understood because of different mechanisms involved.
Collapse
Affiliation(s)
- Costantino Balestra
- Environmental, Occupational, Ageing (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant - HE2BBrussels, Belgium; DAN Europe Research DivisionRoseto, Italy; DAN Europe Research DivisionBrussels, Belgium; Anatomical Research and Clinical Studies (ARCS), Vrije Universiteit BrusselBrussels, Belgium; Anatomical Research Training and Education (ARTE), Vrije Universiteit BrusselBrussels, Belgium; Motor Sciences, Université Libre de BruxellesBrussels, Belgium
| | - Sigrid Theunissen
- Environmental, Occupational, Ageing (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant - HE2BBrussels, Belgium; DAN Europe Research DivisionRoseto, Italy; DAN Europe Research DivisionBrussels, Belgium
| | - Virginie Papadopoulou
- Dayton Lab, Department of Biomedical Engineering, University of North Carolina Chapel Hill, NC, USA
| | - Cedric Le Mener
- Environmental, Occupational, Ageing (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant - HE2B Brussels, Belgium
| | - Peter Germonpré
- DAN Europe Research DivisionRoseto, Italy; DAN Europe Research DivisionBrussels, Belgium; Center for Hyperbaric Oxygen Therapy, Military Hospital "Queen Astrid"Brussels, Belgium
| | - François Guerrero
- DAN Europe Research DivisionRoseto, Italy; DAN Europe Research DivisionBrussels, Belgium; ORPHY Laboratory, EA 4324, Université de Bretagne OccidentaleBrest, France
| | - Pierre Lafère
- DAN Europe Research DivisionRoseto, Italy; DAN Europe Research DivisionBrussels, Belgium; ORPHY Laboratory, EA 4324, Université de Bretagne OccidentaleBrest, France
| |
Collapse
|
15
|
Madden D, Thom SR, Dujic Z. Exercise before and after SCUBA diving and the role of cellular microparticles in decompression stress. Med Hypotheses 2016; 86:80-4. [PMID: 26804603 DOI: 10.1016/j.mehy.2015.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 11/29/2015] [Accepted: 12/09/2015] [Indexed: 11/30/2022]
Abstract
Risk in SCUBA diving is often associated with the presence of gas bubbles in the venous circulation formed during decompression. Although it has been demonstrated time-after-time that, while venous gas emboli (VGE) often accompany decompression sickness (DCS), they are also frequently observed in high quantities in asymptomatic divers following even mild recreational dive profiles. Despite this VGE are commonly utilized as a quantifiable marker of the potential for an individual to develop DCS. Certain interventions such as exercise, antioxidant supplements, vibration, and hydration appear to impact VGE production and the decompression process. However promising these procedures may seem, the data are not yet conclusive enough to warrant changes in decompression procedure, possibly suggesting a component of individual response. We hypothesize that the impact of exercise varies widely in individuals and once tested, recommendations can be made that will reduce individual decompression stress and possibly the incidence of DCS. The understanding of physiological adaptations to diving stress can be applied in different diseases that include endothelial dysfunction and microparticle (MP) production. Exercise before diving is viewed by some as a protective form of preconditioning because some studies have shown that it reduces VGE quantity. We propose that MP production and clearance might be a part of this mechanism. Exercise after diving appears to impact the risk of adverse events as well. Research suggests that the arterialization of VGE presents a greater risk for DCS than when emboli are eliminated by the pulmonary circuit before they have a chance to crossover. Laboratory studies have demonstrated that exercise increases the incidence of crossover likely through extra-cardiac mechanisms such as intrapulmonary arterial-venous anastomoses (IPAVAs). This effect of exercise has been repeated in the field with divers demonstrating a direct relationship between exercise and increased incidence of arterialization.
Collapse
Affiliation(s)
- Dennis Madden
- Department of Integrative Physiology, University of Split School of Medicine, Soltanska 2, 21000 Split, Croatia
| | - Stephen R Thom
- Department of Emergency Medicine, University of Maryland, Baltimore, MD 21201, United States
| | - Zeljko Dujic
- Department of Integrative Physiology, University of Split School of Medicine, Soltanska 2, 21000 Split, Croatia.
| |
Collapse
|
16
|
Madden D, Ljubkovic M, Dujic Z. Intrapulmonary shunt and SCUBA diving: another risk factor? Echocardiography 2015; 32 Suppl 3:S205-10. [PMID: 25693625 DOI: 10.1111/echo.12815] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Laboratory and field investigations have demonstrated that intrapulmonary arteriovenous anastomoses (IPAVA) may provide an additional means for venous gas emboli (VGE) to cross over to the arterial circulation due to their larger diameter compared to pulmonary microcirculation. Once thought to be the primary cause of decompression sickness (DCS), it has been demonstrated that, even in large quantities, their presence does not always result in injury. Normally, VGE are trapped in the site of gas exchange in the lungs and eliminated via diffusion. When VGE crossover takes place in arterial circulation, they have the potential to cause more harm as they are redistributed to the brain, spinal column, and other sensitive tissues. The patent foramen ovale (PFO) was once thought to be the only risk factor for an increase in arterialization; however, IPAVAs represent another pathway for this crossover to occur. The opening of IPAVAs is associated with exercise and hypoxic gas mixtures, both of which divers may encounter. The goal of this review is to describe how IPAVAs may impact diving physiology, specifically during decompression, and what this means for the individual diver as well as the future of commercial and recreational diving. Future research must continue on the relationship between IPAVAs and the environmental and physiological circumstances that lead to their opening and closing, as well as how they may contribute to diving injuries such as DCS.
Collapse
Affiliation(s)
- Dennis Madden
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | | | | |
Collapse
|
17
|
Patent Foramen Ovale in Recreational and Professional Divers: An Important and Largely Unrecognized Problem. Can J Cardiol 2015; 31:1061-6. [PMID: 26143138 DOI: 10.1016/j.cjca.2015.03.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 03/10/2015] [Accepted: 03/10/2015] [Indexed: 11/20/2022] Open
Abstract
Patent foramen ovale (PFO) is associated with an increased risk of decompression sickness (DCS) in divers that results from a paradoxical embolization of nitrogen bubbles. The number of scuba divers worldwide is estimated in the millions, and the prevalence of PFO is 25%-30% in adults. It is interesting that despite these numbers, many important issues regarding optimal screening, risk stratification, and management strategy still remain to be resolved. Recently published data suggest the possible effectiveness of both PFO closure and conservative diving measures in preventing arterial gas embolization. This review aims to introduce the basic principles of physiology and the pathophysiology of bubble formation and DCS, summarize the current literature on PFO and diving, and review the possibilities of diagnostic workup and management.
Collapse
|
18
|
MADDEN DENNIS, THOM STEPHENR, MILOVANOVA TATYANAN, YANG MING, BHOPALE VEENAM, LJUBKOVIC MARKO, DUJIC ZELJKO. Exercise before Scuba Diving Ameliorates Decompression-Induced Neutrophil Activation. Med Sci Sports Exerc 2014; 46:1928-35. [DOI: 10.1249/mss.0000000000000319] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
19
|
Ni XX, Ni M, Fan DF, Sun Q, Kang ZM, Cai ZY, Liu Y, Liu K, Li RP, Xu WG. Heat-shock protein 70 is involved in hyperbaric oxygen preconditioning on decompression sickness in rats. Exp Biol Med (Maywood) 2013; 238:12-22. [PMID: 23479759 DOI: 10.1258/ebm.2012.012101] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Decompression sickness (DCS) is a major concern in diving and space walk. Hyperbaric oxygen (HBO) preconditioning has been proved to enhance tolerance to DCS via nitric oxide. Heat-shock protein (HSP) 70 was also found to have protective effects against DCS. We hypothesized that the beneficial effects of HBO preconditioning on DCS was related to levels of elevated HSP70. HSPs (70, 27 and 90) expressed in tissues of spinal cord and lung in rats was detected at different time points following HBO exposure by Western blot. HSP27 and HSP90 showed a slight but not significant increase after HBO. HSP70 increased and reached highest at 18 h following exposure before decreasing. Then rats were exposed to HBO and subjected to simulated air dive and rapid decompression to induce DCS 18 h after HBO. The severity of DCS, along with levels of HSP70 expression, as well as the extent of oxidative and apoptotic parameters in the lung and spinal cord were compared among different groups of rats pretreated with HBO, HBO plus NG-nitro-l-arginine-methyl ester (l-NAME), HBO plus quercetin or normobaric air. HBO preconditioning significantly reduced the morbidity of DCS (from 66.7% to 36.7%), reduced levels of oxidation (malondialdehyde, 8-hydroxyguanine and hydrogen peroxide) and apoptosis (caspase-3 and -9 activities and the number of apoptotic cells). l-NAME or quercetin eliminated most of the beneficial effects of HBO on DCS, and counteracted the stimulation of HSP70 by HBO. Bubbles in pulmonary artery were detected using ultrasound imaging to observe the possible effect of HBO preconditioning on DCS bubble formation. The amounts of bubbles in rats pretreated with HBO or air showed no difference. These results suggest that HSP70 was involved in the beneficial effects of HBO on DCS in rats, suspected be by the antioxidation and antiapoptosis effects.
Collapse
Affiliation(s)
- Xiao-Xiao Ni
- Department of Diving Medicine, The Second Military Medical University, 800 Xiangyin Road Shanghai 200433, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Papadopoulou V, Eckersley RJ, Balestra C, Karapantsios TD, Tang MX. A critical review of physiological bubble formation in hyperbaric decompression. Adv Colloid Interface Sci 2013; 191-192:22-30. [PMID: 23523006 DOI: 10.1016/j.cis.2013.02.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 02/20/2013] [Accepted: 02/23/2013] [Indexed: 11/15/2022]
Abstract
Bubbles are known to form in the body after scuba dives, even those done well within the decompression model limits. These can sometimes trigger decompression sickness and the dive protocols should therefore aim to limit bubble formation and growth from hyperbaric decompression. Understanding these processes physiologically has been a challenge for decades and there are a number of questions still unanswered. The physics and historical background of this field of study is presented and the latest studies and current developments reviewed. Heterogeneous nucleation is shown to remain the prime candidate for bubble formation in this context. The two main theories to account for micronuclei stability are then to consider hydrophobicity of surfaces or tissue elasticity, both of which could also explain some physiological observations. Finally the modeling relevance of the bubble formation process is discussed, together with that of bubble growth as well as multiple bubble behavior.
Collapse
|
21
|
Sidenafil pre-treatment promotes decompression sickness in rats. PLoS One 2013; 8:e60639. [PMID: 23580342 PMCID: PMC3620342 DOI: 10.1371/journal.pone.0060639] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 03/01/2013] [Indexed: 11/19/2022] Open
Abstract
Vascular bubble formation after decompression contributes to endothelial injuries which form the basis for the development of decompression sickness (DCS). Nitric oxide (NO) is a powerful vasodilator that contributes to vessel homeostasis. It has been shown that NO-releasing agent may reduce bubble formation and prevent serious decompression sickness. The use of sildenafil, a well-known, phosphodiesterase-5 blocker, which act by potentiating the vasodilatory effect on smooth muscle relaxation, has never been studied in DCS. The purpose of the present study was to evaluate the clinical effects of sildenafil pre-treatment on DCS in a rat model. 67 rats were subjected to a simulated dive at 90 msw for 45 min before staged decompression. The experimental group received 10 mg/kg of sildenafil one hour before exposure (n = 35) while controls were not treated (n = 32). Clinical assessment took place over a period of 30 min after surfacing. At the end, blood samples were collected for blood cells counts and the level of circulating bubbles in the right cavities was quantified. There were significantly more manifestations of DCS in the sildenafil group than in the controls (34.3% vs 6.25%, respectively, p = 0.012). Platelet count was more reduced in treated rats than in controls (−21.7% vs −7%, respectively, p = 0.029), whereas bubble grades did not differ between groups. We concluded that pre-treatment with sildenafil promotes the onset and severity of neurological DCS. When considering the use of phosphodiesterase-5 blockers in the context of diving, careful discussion with physician should be recommended.
Collapse
|
22
|
Vallee N, Meckler C, Risso JJ, Blatteau JE. Neuroprotective role of the TREK-1 channel in decompression sickness. J Appl Physiol (1985) 2012; 112:1191-6. [DOI: 10.1152/japplphysiol.01100.2011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nitrogen supersaturation and bubble formation can occur in the vascular system after diving, leading to death and nervous disorders from decompression sickness (DCS). Bubbles alter the vascular endothelium, activate platelets, and lead to focal ischemia with neurological damage mediated by the mechanosensitive TREK-1 neuronal potassium ion channel that sets pre- and postsynaptic resting membrane potentials. We report a neuroprotective effect associated with TREK-1. C57Bl6 mice were subjected to decompression from a simulated 90 msw dive. Of 143 mice that were wild type (WT) for TREK-1, 51.7% showed no DCS, 27.3% failed a grip test, and 21.0% died. Of 88 TREK-1 knockouts (KO), 26.1% showed no DCS, 42.0% failed a grip test, and 31.8% died. Mice that did not express TREK-1 had lower DCS resistance and were more likely to develop neurological symptoms. We conclude that the TREK-1 potassium channel was neuroprotective for DCS.
Collapse
Affiliation(s)
- Nicolas Vallee
- Equipe Résidante de Recherche Subaquatique Opérationnelle, Institut de Recherche Biomédicale des Armées-Toulon, Département Environnement Opérationnel, Unité Environnements Extrêmes, Toulon, France
| | - Cédric Meckler
- Equipe Résidante de Recherche Subaquatique Opérationnelle, Institut de Recherche Biomédicale des Armées-Toulon, Département Environnement Opérationnel, Unité Environnements Extrêmes, Toulon, France
| | - Jean-Jacques Risso
- Equipe Résidante de Recherche Subaquatique Opérationnelle, Institut de Recherche Biomédicale des Armées-Toulon, Département Environnement Opérationnel, Unité Environnements Extrêmes, Toulon, France
| | - Jean-Eric Blatteau
- Equipe Résidante de Recherche Subaquatique Opérationnelle, Institut de Recherche Biomédicale des Armées-Toulon, Département Environnement Opérationnel, Unité Environnements Extrêmes, Toulon, France
| |
Collapse
|