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Willmott AGB, Diment AG, Chung HC, James CA, Maxwell NS, Roberts JD, Gibson OR. Cross-adaptation from heat stress to hypoxia: A systematic review and exploratory meta-analysis. J Therm Biol 2024; 120:103793. [PMID: 38471285 DOI: 10.1016/j.jtherbio.2024.103793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 01/03/2024] [Accepted: 01/12/2024] [Indexed: 03/14/2024]
Abstract
Cross-adaptation (CA) refers to the successful induction of physiological adaptation under one environmental stressor (e.g., heat), to enable subsequent benefit in another (e.g., hypoxia). This systematic review and exploratory meta-analysis investigated the effect of heat acclimation (HA) on physiological, perceptual and physical performance outcome measures during rest, and submaximal and maximal intensity exercise in hypoxia. Database searches in Scopus and MEDLINE were performed. Studies were included when they met the Population, Intervention, Comparison, and Outcome criteria, were of English-language, peer-reviewed, full-text original articles, using human participants. Risk of bias and study quality were assessed using the COnsensus based Standards for the selection of health status Measurement INstruments checklist. Nine studies were included, totalling 79 participants (100 % recreationally trained males). The most common method of HA included fixed-intensity exercise comprising 9 ± 3 sessions, 89 ± 24-min in duration and occurred within 39 ± 2 °C and 32 ± 13 % relative humidity. CA induced a moderate, beneficial effect on physiological measures at rest (oxygen saturation: g = 0.60) and during submaximal exercise (heart rate: g = -0.65, core temperature: g = -0.68 and skin temperature: g = -0.72). A small effect was found for ventilation (g = 0.24) and performance measures (peak power: g = 0.32 and time trial time: g = -0.43) during maximal intensity exercise. No effect was observed for perceptual outcome measures. CA may be appropriate for individuals, such as occupational or military workers, whose access to altitude exposure prior to undertaking submaximal activity in hypoxic conditions is restricted. Methodological variances exist within the current literature, and females and well-trained individuals have yet to be investigated. Future research should focus on these cohorts and explore the mechanistic underpinnings of CA.
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Affiliation(s)
- Ashley G B Willmott
- The Cambridge Centre for Sport and Exercise Sciences (CCSES), Anglia Ruskin University, East Road, Cambridge, United Kingdom; Environmental Extremes Laboratory, University of Brighton, Eastbourne, East Sussex, United Kingdom; Para-Monte Altitude Awareness Charity, Eastbourne, East Sussex, United Kingdom.
| | - Alicia G Diment
- The Cambridge Centre for Sport and Exercise Sciences (CCSES), Anglia Ruskin University, East Road, Cambridge, United Kingdom; Pulmonary Function Laboratory, Norfolk and Norwich University Hospital, Colney Lane, Norwich, Norfolk, United Kingdom.
| | - Henry C Chung
- School of Sport, Rehabilitation and Exercise Sciences (SRES), University of Essex, Colchester, Essex, United Kingdom.
| | - Carl A James
- Hong Kong Sports Institute, Sha Tin, Hong Kong, China; Department of Sport, Physical Education and Health, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.
| | - Neil S Maxwell
- Environmental Extremes Laboratory, University of Brighton, Eastbourne, East Sussex, United Kingdom; Para-Monte Altitude Awareness Charity, Eastbourne, East Sussex, United Kingdom.
| | - Justin D Roberts
- The Cambridge Centre for Sport and Exercise Sciences (CCSES), Anglia Ruskin University, East Road, Cambridge, United Kingdom.
| | - Oliver R Gibson
- Centre for Physical Activity in Health and Disease (CPAHD), Division of Sport, Health and Exercise Sciences, Brunel University London, Uxbridge, United Kingdom.
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Roxburgh BH, Cotter JD, Campbell HA, Reymann U, Wilson LC, Gwynne-Jones D, van Rij AM, Thomas KN. Physiological relationship between cardiorespiratory fitness and fitness for surgery: a narrative review. Br J Anaesth 2023; 130:122-132. [PMID: 36529576 DOI: 10.1016/j.bja.2022.10.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 10/11/2022] [Accepted: 10/24/2022] [Indexed: 12/23/2022] Open
Abstract
Epidemiological evidence has highlighted a strong relationship between cardiorespiratory fitness and surgical outcomes; specifically, fitter patients possess heightened resilience to withstand the surgical stress response. This narrative review draws on exercise and surgical physiology research to discuss and hypothesise the potential mechanisms by which higher fitness affords perioperative benefit. A higher fitness, as indicated by higher peak rate of oxygen consumption and ability to sustain metabolic homeostasis (i.e. higher anaerobic threshold) is beneficial postoperatively when metabolic demands are increased. However, the associated adaptations with higher fitness, and the related participation in regular exercise or physical activity, might also underpin the observed perioperative benefit through a process of hormesis, a protective adaptive response to the moderate and intermittent stress of exercise. Potential mediators discussed include greater antioxidant capacity, metabolic flexibility, glycaemic control, lean body mass, and improved mood.
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Affiliation(s)
- Brendon H Roxburgh
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand; School of Physical Education, Sport and Exercise Sciences, Dunedin, University of Otago, New Zealand.
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, Dunedin, University of Otago, New Zealand
| | - Holly A Campbell
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Ulla Reymann
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Luke C Wilson
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - David Gwynne-Jones
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand; Department of Orthopaedic Surgery, Southern District Health Board, Dunedin, New Zealand
| | - Andre M van Rij
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Kate N Thomas
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
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Horowitz M, Hasin Y. Vascular compliance and left ventricular compliance cross talk: Implications for using long-term heat acclimation in cardiac care. Front Physiol 2023; 14:1074391. [PMID: 36960151 PMCID: PMC10027724 DOI: 10.3389/fphys.2023.1074391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 02/23/2023] [Indexed: 03/09/2023] Open
Abstract
1) The first evidence of the beneficial impact of Long-Term-Heat-Acclimation (LTHA) on cardio-vascular compliance was the positive inotropic response and improved left ventricular (LV) compliance noted when isolated hearts from LTHA rats were studied. Human echo study demonstrates that passive HA affects the right ventricle and the atria as well. 2) There is a cross-talk between vascular and cardiac compliance. Vascular compliance per se is defined by central venous pressure-Blood volume relationship-Global Vascular Compliance (GVC). It is determined by the sum of the vascular compliance of the vessels in every organ in any physiological state, varies with LTHA and thus influences cardiac performance. LTHA improves endothelial function, increases NO (nitric oxide) production, in-turn stimulating alterations in ECM (extracellular matrix) via the TGF β1-SMAD pathway. 3) LTHA is associated with transformation from fast to slow myosin, heat acclimation ischemic/hypoxic cross-tolerance and alterations in the extracellular matrix. 4) A human translational study demonstrated improved LV compliance following bypass surgery in LTHA subjects compared to controls. 5) Diastolic dysfunction and the impact of comorbidities with vascular and non- vascular origins are major contributors to the syndrome of heart failure with preserved ejection function (HFPEF). Unfortunately, there is a paucity of treatment modalities that improve diastolic dysfunction. 6) In the current mini-review we suggest that LTHA may be beneficial to HFPEF patients by remodeling cardiac compliance and vascular response.
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Affiliation(s)
- Michal Horowitz
- Laboratory of Environmental Physiology, Faculty of Dentistry, The Hebrew University of Jerusalem, Jerusalem, Israel
- *Correspondence: Michal Horowitz,
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Rosenberg T, Kisliouk T, Cramer T, Shinder D, Druyan S, Meiri N. Embryonic Heat Conditioning Induces TET-Dependent Cross-Tolerance to Hypothalamic Inflammation Later in Life. Front Genet 2020; 11:767. [PMID: 32849788 PMCID: PMC7419591 DOI: 10.3389/fgene.2020.00767] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 06/29/2020] [Indexed: 11/13/2022] Open
Abstract
Early life encounters with stress can lead to long-lasting beneficial alterations in the response to various stressors, known as cross-tolerance. Embryonic heat conditioning (EHC) of chicks was previously shown to mediate resilience to heat stress later in life. Here we demonstrate that EHC can induce cross-tolerance with the immune system, attenuating hypothalamic inflammation. Inflammation in EHC chicks was manifested, following lipopolysaccharide (LPS) challenge on day 10 post-hatch, by reduced febrile response and reduced expression of LITAF and NFκB compared to controls, as well as nuclear localization and activation of NFκB in the hypothalamus. Since the cross-tolerance effect was long-lasting, we assumed that epigenetic mechanisms are involved. We focused on the role of ten-eleven translocation (TET) family enzymes, which are the mediators of active CpG demethylation. Here, TET transcription during early life stress was found to be necessary for stress resilience later in life. The expression of the TET family enzymes in the midbrain during conditioning increased in parallel to an elevation in concentration of their cofactor α-ketoglutarate. In-ovo inhibition of TET activity during EHC, by the α-ketoglutarate inhibitor bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl) ethyl sulfide (BPTES), resulted in reduced total and locus specific CpG demethylation in 10-day-old chicks and reversed both thermal and inflammatory resilience. In addition, EHC attenuated the elevation in expression of the stress markers HSP70, CRHR1, and CRHR2, during heat challenge on day 10 post-hatch. This reduction in expression was reversed by BPTES. Similarly, the EHC-dependent reduction of inflammatory gene expression during LPS challenge was eliminated in BPTES-treated chicks. Thus, TET family enzymes and CpG demethylation are essential for the embryonic induction of stress cross-tolerance in the hypothalamus.
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Affiliation(s)
- Tali Rosenberg
- Agricultural Research Organization, Volcani Center, Institute of Animal Science, Rishon LeZion, Israel
- Department of Animal Science, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Tatiana Kisliouk
- Agricultural Research Organization, Volcani Center, Institute of Animal Science, Rishon LeZion, Israel
| | - Tomer Cramer
- Agricultural Research Organization, Volcani Center, Institute of Animal Science, Rishon LeZion, Israel
- Department of Animal Science, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Dmitry Shinder
- Agricultural Research Organization, Volcani Center, Institute of Animal Science, Rishon LeZion, Israel
| | - Shelly Druyan
- Agricultural Research Organization, Volcani Center, Institute of Animal Science, Rishon LeZion, Israel
| | - Noam Meiri
- Agricultural Research Organization, Volcani Center, Institute of Animal Science, Rishon LeZion, Israel
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Rosenberg T, Kisliouk T, Ben-Nun O, Cramer T, Meiri N. Cross-tolerance: embryonic heat conditioning induces inflammatory resilience by affecting different layers of epigenetic mechanisms regulating IL6 expression later in life. Epigenetics 2020; 16:228-241. [PMID: 32705933 DOI: 10.1080/15592294.2020.1795596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
A stressor can induce resilience in another, different stressor, a phenomenon known as cross-tolerance. To learn if cross-tolerance is governed by epigenetic regulation, we used embryonic heat conditioning (EHC) in chicks, during the development of the hypothalamus, to increase the immunization response. Indeed, EHC induced a lifelong systemic antibody response to immunization, in addition to reduced hypothalamic IL6 inflammatory expression following LPS challenge. Since the outcome of EHC was long-term cross-tolerance with the immune system, we studied possible epigenetic mechanisms. We first analysed the methylation and hydroxymethylation patterns of IL6. We found reduced hydroxymethylation on IL6 intron 1 in the EHC group, a segment enriched with CpGs and NFkB-binding sites. Luciferase assay in cell lines expressing NFkB showed that IL6 intron 1 is indeed an enhancer. ChiP in the same segment against NFkB in the hypothalamus presented reduced binding to IL6 intron 1 in the EHC group, before and during LPS challenge. In parallel, EHC chicks' IL6 intron 1 presented increased H3K27me3, a repressive translational modification mediated by EZH2. This histone modification occurred during embryonic conditioning and persisted later in life. Moreover, we showed reduced expression of miR-26a, which inhibits EZH2 transcription, during conditioning along with increased EZH2 expression. We demonstrate that stress cross-tolerance, which was indicated by EHC-induced inflammatory resilience and displayed by attenuated inflammatory expression of IL6, is regulated by different epigenetic layers.
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Affiliation(s)
- Tali Rosenberg
- Volcani Center, Institute of Animal Science, Agricultural Research Organization , Rishon LeZiyyon, Israel.,Department of Animal Science, the Robert H. Smith Faculty of Agriculture, Food and Environment, the Hebrew University of Jerusalem , Rehovot, Israel
| | - Tatiana Kisliouk
- Volcani Center, Institute of Animal Science, Agricultural Research Organization , Rishon LeZiyyon, Israel
| | - Osher Ben-Nun
- Volcani Center, Institute of Animal Science, Agricultural Research Organization , Rishon LeZiyyon, Israel.,Department of Animal Science, the Robert H. Smith Faculty of Agriculture, Food and Environment, the Hebrew University of Jerusalem , Rehovot, Israel
| | - Tomer Cramer
- Volcani Center, Institute of Animal Science, Agricultural Research Organization , Rishon LeZiyyon, Israel.,Department of Animal Science, the Robert H. Smith Faculty of Agriculture, Food and Environment, the Hebrew University of Jerusalem , Rehovot, Israel
| | - Noam Meiri
- Volcani Center, Institute of Animal Science, Agricultural Research Organization , Rishon LeZiyyon, Israel
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Salgado RM, Coffman KE, Bradbury KE, Mitchell KM, Yurkevicius BR, Luippold AJ, Mayer TA, Charkoudian N, Alba BK, Fulco CS, Kenefick RW. Effect of 8 days of exercise-heat acclimation on aerobic exercise performance of men in hypobaric hypoxia. Am J Physiol Regul Integr Comp Physiol 2020; 319:R114-R122. [PMID: 32432914 DOI: 10.1152/ajpregu.00048.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Exercise-heat acclimation (EHA) induces adaptations that improve tolerance to heat exposure. Whether adaptations from EHA can also alter responses to hypobaric hypoxia (HH) conditions remains unclear. This study assessed whether EHA can alter time-trial performance and/or incidence of acute mountain sickness (AMS) during HH exposure. Thirteen sea-level (SL) resident men [SL peak oxygen consumption (V̇o2peak) 3.19 ± 0.43 L/min] completed steady-state exercise, followed by a 15-min cycle time trial and assessment of AMS before (HH1; 3,500 m) and after (HH2) an 8-day EHA protocol [120 min; 5 km/h; 2% incline; 40°C and 40% relative humidity (RH)]. EHA induced lower heart rate (HR) and core temperature and plasma volume expansion. Time-trial performance was not different between HH1 and HH2 after 2 h (106.3 ± 23.8 vs. 101.4 ± 23.0 kJ, P = 0.71) or 24 h (107.3 ± 23.4 vs. 106.3 ± 20.8 kJ, P > 0.9). From HH1 to HH2, HR and oxygen saturation, at the end of steady-state exercise and time-trial tests at 2 h and 24 h, were not different (P > 0.05). Three of 13 volunteers developed AMS during HH1 but not during HH2, whereas a fourth volunteer only developed AMS during HH2. Heat shock protein 70 was not different from HH1 to HH2 at SL [1.9 ± 0.7 vs. 1.8 ± 0.6 normalized integrated intensities (NII), P = 0.97] or after 23 h (1.8 ± 0.4 vs. 1.7 ± 0.5 NII, P = 0.78) at HH. Our results indicate that this EHA protocol had little to no effect-neither beneficial nor detrimental-on exercise performance in HH. EHA may reduce AMS in those who initially developed AMS; however, studies at higher elevations, having higher incidence rates, are needed to confirm our findings.
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Affiliation(s)
- Roy M Salgado
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Kirsten E Coffman
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts.,Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee
| | - Karleigh E Bradbury
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Katherine M Mitchell
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Beau R Yurkevicius
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts.,Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee
| | - Adam J Luippold
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Thomas A Mayer
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts.,Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee
| | - Nisha Charkoudian
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Billie K Alba
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts.,Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee
| | - Charles S Fulco
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts.,Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee
| | - Robert W Kenefick
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
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Hong L, Sun Y, An JZ, Wang C, Qiao SG. Sevoflurane Preconditioning Confers Delayed Cardioprotection by Upregulating AMP-Activated Protein Kinase Levels to Restore Autophagic Flux in Ischemia-Reperfusion Rat Hearts. Med Sci Monit 2020; 26:e922176. [PMID: 32476662 PMCID: PMC7288833 DOI: 10.12659/msm.922176] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Background Volatile anesthetic preconditioning confers delayed cardioprotection against ischemia/reperfusion injury (I/R). AMP-activated protein kinase (AMPK) takes part in autophagy activation. Furthermore, autophagic flux is thought to be impaired after I/R. We hypothesized that delayed cardioprotection can restore autophagic flux by activating AMPK. Material/Methods All male rat hearts underwent 30-min ischemia and 120-min reperfusion with or without sevoflurane exposure. AMPK inhibitor compound C (250 μg/kg, iv) was given at the reperfusion period. Autophagic flux blocker chloroquine (10 mg/kg, ip) was administrated 1 h before the experiment. Myocardial infarction, nicotinamide adenine dinucleotide (NAD+) content, and cytochrome c were measured. To evaluate autophagic flux, the markers of microtubule-associated protein 1 light chain 3 (LC3) I and II, P62 and Beclin 1, and lysosome-associated membrane protein-2 (LAMP 2) were analyzed. Results The delayed cardioprotection enhanced post-ischemic AMPK activation, reduced infarction, CK-MB level, NAD+ content loss and cytochrome c release, and compound C blocked these effects. Sevoflurane restored impaired autophagic flux through a lower ratio of LC3II/LC3I, downregulation of P62 and Beclin 1, and higher expression in LAMP 2. Consistently, compound C inhibited these changes of autophagy flux. Moreover, chloroquine pretreatment abolished sevoflurane-induced infarct size reduction, CK-MB level, NAD+ content loss, and cytochrome c release, with concomitant increase the ratios of LC3II/LC3I and levels of P62 and Beclin 1, but p-AMPK expression was not downregulated by chloroquine. Conclusions Sevoflurane exerts a delayed cardioprotective effects against myocardial injury in rats by activation of AMPK and restoration of I/R-impaired autophagic flux.
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Affiliation(s)
- Lei Hong
- Institute of Clinical Medicine Research, The Affiliated Suzhou Science and Technology Town Hospital of Nanjing Medical University, Suzhou, Jiangsu, China (mainland)
| | - Ying Sun
- Institute of Clinical Medicine Research, The Affiliated Suzhou Science and Technology Town Hospital of Nanjing Medical University, Suzhou, Jiangsu, China (mainland)
| | - Jian-Zhong An
- Institute of Clinical Medicine Research, The Affiliated Suzhou Science and Technology Town Hospital of Nanjing Medical University, Suzhou, Jiangsu, China (mainland)
| | - Chen Wang
- Institute of Clinical Medicine Research, The Affiliated Suzhou Science and Technology Town Hospital of Nanjing Medical University, Suzhou, Jiangsu, China (mainland)
| | - Shi-Gang Qiao
- Institute of Clinical Medicine Research, The Affiliated Suzhou Science and Technology Town Hospital of Nanjing Medical University, Suzhou, Jiangsu, China (mainland)
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