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Chua JYX, Kan EM, Lee PP, Shorey S. Application of the Stanford Biodesign Framework in Healthcare Innovation Training and Commercialization of Market Appropriate Products: A Scoping Review. J Med Syst 2024; 48:44. [PMID: 38647719 DOI: 10.1007/s10916-024-02067-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 04/11/2024] [Indexed: 04/25/2024]
Abstract
The Stanford Biodesign needs-centric framework can guide healthcare innovators to successfully adopt the 'Identify, Invent and Implement' framework and develop new healthcare innovations products to address patients' needs. This scoping review explored the application of the Stanford Biodesign framework for healthcare innovation training and the development of novel healthcare innovative products. Seven electronic databases were searched from their respective inception dates till April 2023: PubMed, Embase, CINAHL, PsycINFO, Web of Science, Scopus, ProQuest Dissertations, and Theses Global. This review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for Scoping Reviews and was guided by the Arksey and O'Malley's scoping review framework. Findings were analyzed using Braun and Clarke's thematic analysis framework. Three themes and eight subthemes were identified from the 26 included articles. The main themes are: (1) Making a mark on healthcare innovation, (2) Secrets behind success, and (3) The next steps. The Stanford Biodesign framework guided healthcare innovation teams to develop new medical products and achieve better patient health outcomes through the induction of training programs and the development of novel products. Training programs adopting the Stanford Biodesign approach were found to be successful in improving trainees' entrepreneurship, innovation, and leadership skills and should continue to be promoted. To aid innovators in commercializing their newly developed medical products, additional support such as securing funds for early start-up companies, involving clinicians and users in product testing and validation, and establishing new guidelines and protocols for the new healthcare products would be needed.
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Affiliation(s)
- Joelle Yan Xin Chua
- Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore, Level 2, Clinical Research Centre, Block MD11, 10 Medical Drive, Singapore, 117597, Singapore
| | - Enci Mary Kan
- Singapore Biodesign, Agency for Science, Technology and Research, Singapore, Singapore
- Innovation & Entrepreneurship, Duke-NUS Medical School, Singapore, Singapore
| | - Phin Peng Lee
- Singapore Biodesign, Agency for Science, Technology and Research, Singapore, Singapore
- Innovation & Entrepreneurship, Duke-NUS Medical School, Singapore, Singapore
| | - Shefaly Shorey
- Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore, Level 2, Clinical Research Centre, Block MD11, 10 Medical Drive, Singapore, 117597, Singapore.
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Verma SK, Kan EM, Lu J, Ng KC, Ling EA, Seramani S, Kn BP, Wong YC, Tan MH, Velan SS. Multi-echo susceptibility-weighted imaging and histology of open-field blast-induced traumatic brain injury in a rat model. NMR Biomed 2015; 28:1069-1077. [PMID: 26152641 DOI: 10.1002/nbm.3351] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 05/18/2015] [Accepted: 06/03/2015] [Indexed: 06/04/2023]
Abstract
Blast-induced traumatic brain injury is on the rise, predominantly as a result of the use of improvised explosive devices, resulting in undesirable neuropsychological dysfunctions, as demonstrated in both animals and humans. This study investigated the effect of open-field blast injury on the rat brain using multi-echo, susceptibility-weighted imaging (SWI). Multi-echo SWI provided phase maps with better signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), making it a sensitive technique for brain injury. Male Sprague-Dawley rats were subjected to a survivable blast of 180 kPa. The visibility of blood vessels of varying sizes improved with multi-echo SWI. Reduced signal intensity from major vessels post-blast indicates increased deoxyhaemoglobin. Relative cerebral blood flow was computed from filtered phase SWI images using inferred changes in oxygen saturation from major blood vessels. Cerebral blood flow decreased significantly at day 3 and day 5 post-blast compared with that pre-blast. This was substantiated by the upregulation of β-amyloid precursor protein (β-APP), a marker of ischaemia, in the neuronal perikaya of the cerebral cortex, as observed by immunofluorescence, and in the cortical tissue by western blot analysis. Our findings indicate the presence of brain ischaemia in post-blast acute phase of injury with possible recovery subsequently. Our results from cerebrovascular imaging, histology and staining provide an insight into the ischaemic state of the brain post-blast and may be useful for prognosis and outcome.
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Affiliation(s)
- Sanjay Kumar Verma
- Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Singapore
| | - Enci Mary Kan
- Defence Medical and Environmental Research Institute, DSO National Laboratories, Singapore
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Jia Lu
- Defence Medical and Environmental Research Institute, DSO National Laboratories, Singapore
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Kian Chye Ng
- Defence Medical and Environmental Research Institute, DSO National Laboratories, Singapore
| | - Eng Ang Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Sankar Seramani
- Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Singapore
| | - Bhanu Prakash Kn
- Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Singapore
| | - Yong Chiat Wong
- Defence Medical and Environmental Research Institute, DSO National Laboratories, Singapore
| | - Mui Hong Tan
- Defence Medical and Environmental Research Institute, DSO National Laboratories, Singapore
| | - S Sendhil Velan
- Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Singapore
- Clinical Imaging Research Centre, Agency for Science, Technology and Research, Singapore
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Yuan Y, Rangarajan P, Kan EM, Wu Y, Wu C, Ling EA. Scutellarin regulates the Notch pathway and affects the migration and morphological transformation of activated microglia in experimentally induced cerebral ischemia in rats and in activated BV-2 microglia. J Neuroinflammation 2015; 12:11. [PMID: 25600517 PMCID: PMC4316603 DOI: 10.1186/s12974-014-0226-z] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 12/19/2014] [Indexed: 01/06/2023] Open
Abstract
Background Activated microglial cells release an excess of inflammatory mediators after an ischemic stroke. We reported previously that scutellarin effectively suppressed the inflammatory response induced by activated microglia in rats subjected to middle cerebral artery occlusion (MCAO); however, the mechanism via which scutellarin exerts its effects on microglial activation has not been explored. This study aimed to elucidate if scutellarin can regulate the Notch pathway that is linked to microglia activation in MCAO rat, and in lipopolysaccharide (LPS)-induced BV-2 microglia. Along with this, we also investigated some characteristic behavioral responses of activated microglia. Methods Expression of various members of the Notch pathway, including Notch-1, intracellular Notch receptor domain (NICD), recombining binding protein suppressor of hairless (RBP-JK) and transcription factor hairy and enhancer of split-1 (Hes-1) in activated microglia was assessed by immunofluorescence staining and western blot after experimental MCAO and in vitro LPS activation. The effect of scutellarin on migration of microglia was determined by the transwell chamber assay as well as expression of monocyte chemoattractant protein-1 (MCP-1). The morphological change of microglia induced by scutellarin was detected by F-actin staining and electron microscopy. Results Scutellarin markedly attenuated the expression of NF-κB, Notch-1, NICD, RBP-JK and Hes-1 both in vivo and in activated microglia. It decreased the expression of MCP-1 and microglial migration, but increased the ability of microglia adhesion. Scutellarin also altered the phenotype of microglia by causing rearrangement or reorganization of its cytoskeleton. Conclusions The results suggest that scutellarin regulates the activation of microglia via the Notch pathway and concurrently induces morphological and functional changes in activated microglia. Electronic supplementary material The online version of this article (doi:10.1186/s12974-014-0226-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yun Yuan
- Department of Anatomy and Histology/Embryology, Faculty of Basic Medical Sciences, Kunming Medical University, 1168 West Chunrong Road, Kunming, 650500, PR China.
| | - Parakalan Rangarajan
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, 4 Medical Drive, MD10, Singapore, 117597, Singapore.
| | - Enci Mary Kan
- Defense Medical and Environmental Research Institute, DSO National Laboratories, 27 Medical Drive, Singapore, 117510, Singapore.
| | - Yajun Wu
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, 4 Medical Drive, MD10, Singapore, 117597, Singapore.
| | - Chunyun Wu
- Department of Anatomy and Histology/Embryology, Faculty of Basic Medical Sciences, Kunming Medical University, 1168 West Chunrong Road, Kunming, 650500, PR China.
| | - Eng-Ang Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, 4 Medical Drive, MD10, Singapore, 117597, Singapore.
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Zou YY, Yuan Y, Kan EM, Lu J, Ling EA. Combustion smoke-induced inflammation in the olfactory bulb of adult rats. J Neuroinflammation 2014; 11:176. [PMID: 25297558 PMCID: PMC4197300 DOI: 10.1186/s12974-014-0176-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 09/29/2014] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The damaging effect of combustion smoke inhalation on the lung is widely reported but information on its effects on the olfactory bulb is lacking. This study sought to determine the effects of smoke inhalation on the olfactory bulb, whose afferent input neurons in the nasal mucosa are directly exposed to external stimuli, such as smoke. METHODS Adult male Sprague-Dawley rats were subjected to combustion smoke inhalation and sacrificed at different time points. Changes in olfactory bulb proteins including vascular endothelial growth factor (VEGF), inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), neuronal nitric oxide synthase (nNOS), Na+-K+-Cl- cotransporter 1 (NKCC1), glial fibrillary acidic protein (GFAP), and aquaporin-4 (AQP4) were evaluated by Western blot analysis. In addition, ELISA was conducted for cytokine and chemokine levels, and double immunofluorescence labeling was carried out for GFAP/VEGF, GFAP/AQP4, NeuN/nNOS, GFAP/NKCC1, NeuN/NKCC1, GFAP/Rhodamine isothiocyanate (RITC), and transferase dUTP nick end labeling (TUNEL). Aminoguanidine was administered to determine the effects of iNOS inhibition on the targets probed after smoke inhalation. RESULTS The results showed a significant increase in VEGF, iNOS, eNOS, nNOS, NKCC1, and GFAP expression in the bulb tissues, with corresponding increases in inflammatory cytokines and chemokines after smoke inhalation. Concurrent to this was a drastic increase in AQP4 expression and RITC permeability. Aminoguanidine administration decreased the expression of iNOS and RITC extravasation after smoke inhalation. This was coupled with a significant reduction in incidence of TUNEL + cells that was not altered with administration of L-NG-nitroarginine methyl ester (L-NAME). CONCLUSIONS These findings suggest that the upregulation of iNOS in response to smoke inhalation plays a major role in the olfactory bulb inflammatory pathophysiology, along with a concomitant increase in pro-inflammatory molecules, vascular permeability, and edema. Overall, these findings indicate that the olfactory bulb is vulnerable to smoke inhalation.
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Yang L, Kan EM, Lu J, Wu C, Ling EA. Expression of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) and its roles in activated microglia in vivo and in vitro. J Neuroinflammation 2014; 11:148. [PMID: 25148928 PMCID: PMC4244045 DOI: 10.1186/s12974-014-0148-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 08/07/2014] [Indexed: 11/21/2022] Open
Abstract
Background We reported previously that amoeboid microglial cells in the postnatal rat brain expressed 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase) both in vivo and in vitro; however, the functional role of CNPase in microglia has remained uncertain. This study extended the investigation to determine CNPase expression in activated microglia derived from cell culture and animal models of brain injury with the objective to clarify its putative functions. Methods Three-day-old Wistar rats were given an intraperitoneal injection of lipopolysaccharide to induce microglial activation, and the rats were killed at different time points. Along with this, primary cultured microglial cells were subjected to lipopolysaccharide treatment, and expression of CNPase was analyzed by real-time reverse transcription PCR and immunofluorescence. Additionally, siRNA transfection was employed to downregulate CNPase in BV-2 cells. Following this, inducible nitric oxide synthase, IL-1β and TNF-α were determined at mRNA and protein levels. Reactive oxygen species and nitric oxide were also assessed by flow cytometry and colorimetric assay, respectively. In parallel to this, CNPase expression in activated microglia was also investigated in adult rats subjected to fluid percussion injury as well as middle cerebral artery occlusion. Results In vivo, CNPase immunofluorescence in activated microglia was markedly enhanced after lipopolysaccharide treatment. A similar feature was observed in the rat brain after fluid percussion injury and middle cerebral artery occlusion. In vitro, CNPase protein and mRNA expression was increased in primary microglia with lipopolysaccharide stimulation. Remarkably, inducible nitric oxide synthase, IL-1β, TNF-α, reactive oxygen species and nitric oxide were significantly upregulated in activated BV-2 cells with CNPase knockdown. siRNA knockdown of CNPase increased microglia migration; on the other hand, microglial cells appeared to be arrested at G1 phase. Conclusions The present results have provided the first morphological and molecular evidence that CNPase expression is increased in activated microglia. CNPase knockdown resulted in increased expression of various inflammatory mediators. It is concluded that CNPase may play an important role as a putative anti-inflammatory gene both in normal and injured brain. Electronic supplementary material The online version of this article (doi:10.1186/s12974-014-0148-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | - Eng-Ang Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.
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Zou YY, Kan EM, Cao Q, Lu J, Ling EA. Combustion smoke-induced inflammation in the cerebellum and hippocampus of adult rats. Neuropathol Appl Neurobiol 2014; 39:531-52. [PMID: 23106634 DOI: 10.1111/nan.12001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 10/23/2012] [Indexed: 12/12/2022]
Abstract
AIMS The effect of combustion smoke inhalation on the respiratory system is widely reported but its effects on the central nervous system remain unclear. Here, we aimed to determine the effects of smoke inhalation on the cerebellum and hippocampus which are areas vulnerable to hypoxia injury. METHODS Adult male Sprague-Dawley rats were subjected to combustion smoke inhalation and sacrificed at 0.5, 3, 24 and 72 h after exposure. The cerebellum and hippocampus were subjected to Western analysis for VEGF, iNOS, eNOS, nNOS and AQP4 expression; ELISA analysis for cytokine and chemokine levels; and immunohistochemistry for GFAP/AQP4, RECA-1/RITC and TUNEL. Aminoguanidine (AG) was administered to determine the effects of iNOS after smoke inhalation. RESULTS Both the cerebellum and hippocampus showed a significant increase in VEGF, iNOS, eNOS, nNOS and AQP4 expression with corresponding increases in inflammatory cytokines and chemokines and increased AQP4 expression and RITC permeability after smoke exposure. AG was able to decrease the expression of iNOS, followed by VEGF, eNOS, nNOS, RITC and AQP4 after smoke exposure. There was also a significant increase in TUNEL+ cells in the cerebellum and hippocampus which were not significantly reduced by AG. Beam walk test revealed immediate deficits after smoke inhalation which was attenuated with AG. CONCLUSION The findings suggest that iNOS plays a major role in the central nervous system inflammatory pathophysiology after smoke inhalation exposure with concomitant increase in proinflammatory molecules, vascular permeability and oedema, for which the cerebellum appears to be more vulnerable to smoke exposure than the hippocampus.
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Affiliation(s)
- Y-Y Zou
- Department of Pathology, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, China
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Chong SJ, Kan EM, Song C, Soh CR, Lu J. Characterization of early thermal burns and the effects of hyperbaric oxygen treatment: a pilot study. Diving Hyperb Med 2013; 43:157-161. [PMID: 24122191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 06/16/2013] [Indexed: 06/02/2023]
Abstract
BACKGROUND AND AIMS Studies investigating hyperbaric oxygen treatment (HBOT) to improve outcome in burns have been inconclusive. In this study, we aimed to characterize early thermal burns injury in adult patients with < 40% total body surface area (TBSA) and to determine the effects of HBOT administered within 24 h to 48 h of a burn injury. METHODS Seventeen subjects were randomized into control (n = 9) and HBOT treatment (n = 8) arms. Burn depth, measured by laser Doppler imaging (LDI) and histologically, white blood cell (WBC) count and plasma cytokine inflammatory markers were assessed at 24 h (pre HBOT) and 48 h (post HBOT) post burn, as were immunohistochemistry and microbiology of burns tissue samples at 48 h post burn. RESULTS WBC count and serum interleukin (IL)-1β, IL-4, IL-6, IL-10 and interferon-γ were significantly elevated 24 h after burn, but no significant changes in any of these parameters were found with HBOT. HBOT had no significant effect on burn depth. Two HBOT patients and four control patients developed positive bacterial cultures. CONCLUSIONS Slower than anticipated recruitment resulted in considerably fewer patients than planned being studied. Inflammatory markers were significantly increased at 24 h in patients with < 40% TBSA burn. Early HBOT had no apparent effects on any of the parameters measured in this small pilot study. HBOT may possibly have a broad-spectrum antimicrobial effect worthy of further study. We report our methodology in detail as a possible model for future burns studies.
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Affiliation(s)
- Si Jack Chong
- Navy Medical Services, Republic of Singapore Navy and Department of Plastic, Reconstructive and Aesthetic Surgery Singapore General Hospital Outram Road, Singapore 169608 Phone: +65-9146-7592, E-mail:
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Zou YY, Kan EM, Lu J, Ng KC, Tan MH, Yao L, Ling EA. Primary blast injury-induced lesions in the retina of adult rats. J Neuroinflammation 2013; 10:79. [PMID: 23819902 PMCID: PMC3707737 DOI: 10.1186/1742-2094-10-79] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Accepted: 06/27/2013] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The effect of primary blast exposure on the brain is widely reported but its effects on the eye remains unclear. Here, we aim to examine the effects of primary blast exposure on the retina. METHODS Adult male Sprague-Dawley rats were exposed to primary blast high and low injury and sacrificed at 24 h, 72 h, and 2 weeks post injury. The retina was subjected to western analysis for vascular endothelial growth factor (VEGF), aquaporin-4 (AQP4), glutamine synthethase (GS), inducible nitric oxide synthase (NOS), endothelial NOS, neuronal NOS and nestin expression; ELISA analysis for cytokines and chemokines; and immunofluorescence for glial fibrillary acidic protein (GFAP)/VEGF, GFAP/AQP4, GFAP/nestin, GS/AQP4, lectin/iNOS, and TUNEL. RESULTS The retina showed a blast severity-dependent increase in VEGF, iNOS, eNOS, nNOS, and nestin expression with corresponding increases in inflammatory cytokines and chemokines. There was also increased AQP4 expression and retinal thickness after primary blast exposure that was severity-dependent. Finally, a significant increase in TUNEL+ and Caspase-3+ cells was observed. These changes were observed at 24 h post-injury and sustained up to 2 weeks post injury. CONCLUSIONS Primary blast resulted in severity-dependent pathological changes in the retina, manifested by the increased expression of a variety of proteins involved in inflammation, edema, and apoptosis. These changes were observed immediately after blast exposure and sustained up to 2 weeks suggesting acute and chronic injury mechanisms. These changes were most obvious in the astrocytes and Müller cells and suggest important roles for these cells in retina pathophysiology after blast.
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Affiliation(s)
- Ying-Ying Zou
- Department of Pathology, Faculty of Basic Medical Sciences, Kunming Medical University, 1168 West Chunrong Road, Kunming, PR China
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Li X, Kan EM, Lu J, Cao Y, Wong RK, Keshavarzian A, Wilder-Smith CH. Combat-training increases intestinal permeability, immune activation and gastrointestinal symptoms in soldiers. Aliment Pharmacol Ther 2013; 37:799-809. [PMID: 23432460 DOI: 10.1111/apt.12269] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 07/30/2012] [Accepted: 02/07/2013] [Indexed: 12/16/2022]
Abstract
BACKGROUND Gastrointestinal (GI) symptoms are common in soldiers in combat or high-pressure operational situations and often lead to compromised performance. Underlying mechanisms are unclear, but neuroendocrine dysregulation, immune activation and increased intestinal permeability may be involved in stress-related GI dysfunction. AIM To study the effects of prolonged, intense, mixed psychological and physical stress on intestinal permeability, systemic inflammatory and stress markers in soldiers during high-intensity combat-training. METHODS In 37 male army medical rapid response troops, GI symptoms, stress markers, segmental intestinal permeability using the 4-sugar test (sucrose, lactulose, mannitol and sucralose) and immune activation were assessed during the 4th week of an intense combat-training and a rest period. RESULTS Combat-training elicited higher stress, anxiety and depression scores (all P < 0.01) as well as greater incidence and severity of GI symptoms [irritable bowel syndrome symptom severity score (IBS-SSS), P < 0.05] compared with rest. The IBS-SSS correlated with depression (r = 0.41, P < 0.01) and stress (r = 0.40, P < 0.01) ratings. Serum levels of cortisol, interleukin-6, and tumour necrosis factor-α, and segmental GI permeability increased during combat-training compared with rest (all P < 0.05). The lactulose:mannitol ratio was higher in soldiers with GI symptoms (IBS-SSS ≥75) during combat-training than those without (IBS-SSS <75) (P < 0.05). CONCLUSIONS Prolonged combat-training not only induces the expected increases in stress, anxiety and depression, but also GI symptoms, pro-inflammatory immune activation and increased intestinal permeability. Identification of subgroups of individuals at high-risk of GI compromise and of long-term deleterious effects of operational stress as well as the development of protective measures will be the focus of future studies.
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Affiliation(s)
- X Li
- Neurogastroenterology Research Unit, Department of Medicine, National University of Singapore, Singapore
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Yao L, Kan EM, Lu J, Hao A, Dheen ST, Kaur C, Ling EA. Toll-like receptor 4 mediates microglial activation and production of inflammatory mediators in neonatal rat brain following hypoxia: role of TLR4 in hypoxic microglia. J Neuroinflammation 2013; 10:23. [PMID: 23388509 PMCID: PMC3575244 DOI: 10.1186/1742-2094-10-23] [Citation(s) in RCA: 207] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 01/25/2013] [Indexed: 11/20/2022] Open
Abstract
Background Hypoxia induces microglial activation which causes damage to the developing brain. Microglia derived inflammatory mediators may contribute to this process. Toll-like receptor 4 (TLR4) has been reported to induce microglial activation and cytokines production in brain injuries; however, its role in hypoxic injury remains uncertain. We investigate here TLR4 expression and its roles in neuroinflammation in neonatal rats following hypoxic injury. Methods One day old Wistar rats were subjected to hypoxia for 2 h. Primary cultured microglia and BV-2 cells were subjected to hypoxia for different durations. TLR4 expression in microglia was determined by RT-PCR, western blot and immunofluorescence staining. Small interfering RNA (siRNA) transfection and antibody neutralization were employed to downregulate TLR4 in BV-2 and primary culture. mRNA and protein expression of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and inducible nitric oxide synthase (iNOS) was assessed. Reactive oxygen species (ROS), nitric oxide (NO) and NF-κB levels were determined by flow cytometry, colorimetric and ELISA assays respectively. Hypoxia-inducible factor-1 alpha (HIF-1α) mRNA and protein expression was quantified and where necessary, the protein expression was depleted by antibody neutralization. In vivo inhibition of TLR4 with CLI-095 injection was carried out followed by investigation of inflammatory mediators expression via double immunofluorescence staining. Results TLR4 immunofluorescence and protein expression in the corpus callosum and cerebellum in neonatal microglia were markedly enhanced post-hypoxia. In vitro, TLR4 protein expression was significantly increased in both primary microglia and BV-2 cells post-hypoxia. TLR4 neutralization in primary cultured microglia attenuated the hypoxia-induced expression of TNF-α, IL-1β and iNOS. siRNA knockdown of TLR4 reduced hypoxia-induced upregulation of TNF-α, IL-1β, iNOS, ROS and NO in BV-2 cells. TLR4 downregulation-mediated inhibition of inflammatory cytokines in primary microglia and BV-2 cells was accompanied by the suppression of NF-κB activation. Furthermore, HIF-1α antibody neutralization attenuated the increase of TLR4 expression in hypoxic BV-2 cells. TLR4 inhibition in vivo attenuated the immunoexpression of TNF-α, IL-1β and iNOS on microglia post-hypoxia. Conclusion Activated microglia TLR4 expression mediated neuroinflammation via a NF-κB signaling pathway in response to hypoxia. Hence, microglia TLR4 presents as a potential therapeutic target for neonatal hypoxia brain injuries.
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Affiliation(s)
- Linli Yao
- Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong Provincial Key Laboratory of Mental Disorders, Department of Histology and Embryology, Shandong University School of Medicine, 250012, Jinan, China
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Kan EM, Ling EA, Lu J. Microenvironment changes in mild traumatic brain injury. Brain Res Bull 2012; 87:359-72. [PMID: 22289840 DOI: 10.1016/j.brainresbull.2012.01.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 01/10/2012] [Accepted: 01/12/2012] [Indexed: 02/08/2023]
Abstract
Traumatic brain injury (TBI) is a major public-health problem for which mild TBI (MTBI) makes up majority of the cases. MTBI is a poorly-understood health problem and can persist for years manifesting into neurological and non-neurological problems that can affect functional outcome. Presently, diagnosis of MTBI is based on symptoms reporting with poor understanding of ongoing pathophysiology, hence precluding prognosis and intervention. Other than rehabilitation, there is still no pharmacological treatment for the treatment of secondary injury and prevention of the development of cognitive and behavioural problems. The lack of external injuries and absence of detectable brain abnormalities lend support to MTBI developing at the cellular and biochemical level. However, the paucity of suitable and validated non-invasive methods for accurate diagnosis of MTBI poses as a substantial challenge. Hence, it is crucial that a clinically useful evaluation and management procedure be instituted for MTBI that encompasses both molecular pathophysiology and functional outcome. The acute microenvironment changes post-MTBI presents an attractive target for modulation of MTBI symptoms and the development of cognitive changes later in life.
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Affiliation(s)
- Enci Mary Kan
- Combat Care Laboratory, Defence Medical and Environmental Research Institute, DSO National Laboratories, 27 Medical Drive, Singapore 117510, Singapore
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Lu J, Ng KC, Ling G, Wu J, Poon DJF, Kan EM, Tan MH, Wu YJ, Li P, Moochhala S, Yap E, Lee LKH, Teo M, Yeh IB, Sergio DMB, Chua F, Kumar SD, Ling EA. Effect of blast exposure on the brain structure and cognition in Macaca fascicularis. J Neurotrauma 2011; 29:1434-54. [PMID: 21639720 DOI: 10.1089/neu.2010.1591] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Blast injury to the brain is one of the major causes of death and can also significantly affect cognition and physical and psychological skills in survivors of blast. The complex mechanisms via which blast injury causes impairment of cognition and other symptoms are poorly understood. In this study, we investigated the effects of varying degrees of primary blast overpressure (BOP; 80 and 200 kPa) on the pathophysiological and magnetic resonance imaging (MRI) changes and neurocognitive performance as assessed by the monkey Cambridge Neuropsychological Test Automated Battery (mCANTAB) in non-human primates (NHP). The study aimed to examine the effects of neurobehavioral and histopathological changes in NHP. MRI and histopathology revealed ultrastructural changes in the brain, notably in the Purkinje neurons in the cerebellum and pyramidal neurons in the hippocampus, which were most vulnerable to the blast. The results correlated well with the behavioral changes and changes in motor coordination and working memory of the affected monkeys. In addition, there was white matter damage affecting myelinated axons, astrocytic hypertrophy, and increased aquaporin-4 (AQP-4) expression in astrocytes, suggesting cerebral edema. Increased apoptosis appeared to involve astrocytes and oligodendrocytes in the animals following blast exposure. The small sample size could have contributed to the non-significant outcome in cognitive performance post-blast and limited quantitative analyses. Nevertheless, the study has provided initial descriptive changes for establishing a primary BOP threshold for brain injury to serve as a useful platform for future investigations that aim to estimate brain injury potential and set safe limits of exposure.
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Affiliation(s)
- Jia Lu
- Defence Medical and Environmental Research Institute, DSO National Laboratories, Singapore 117510.
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Pun PBL, Kan EM, Salim A, Li Z, Ng KC, Moochhala SM, Ling EA, Tan MH, Lu J. Low level primary blast injury in rodent brain. Front Neurol 2011; 2:19. [PMID: 21541261 PMCID: PMC3083909 DOI: 10.3389/fneur.2011.00019] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Accepted: 03/15/2011] [Indexed: 01/21/2023] Open
Abstract
The incidence of blast attacks and resulting traumatic brain injuries has been on the rise in recent years. Primary blast is one of the mechanisms in which the blast wave can cause injury to the brain. The aim of this study was to investigate the effects of a single sub-lethal blast over pressure (BOP) exposure of either 48.9 kPa (7.1 psi) or 77.3 kPa (11.3 psi) to rodents in an open-field setting. Brain tissue from these rats was harvested for microarray and histopathological analyses. Gross histopathology of the brains showed that cortical neurons were “darkened” and shrunken with narrowed vasculature in the cerebral cortex day 1 after blast with signs of recovery at day 4 and day 7 after blast. TUNEL-positive cells were predominant in the white matter of the brain at day 1 after blast and double-labeling of brain tissue showed that these DNA-damaged cells were both oligodendrocytes and astrocytes but were mainly not apoptotic due to the low caspase-3 immunopositivity. There was also an increase in amyloid precursor protein immunoreactive cells in the white matter which suggests acute axonal damage. In contrast, Iba-1 staining for macrophages or microglia was not different from control post-blast. Blast exposure altered the expression of over 5786 genes in the brain which occurred mostly at day 1 and day 4 post-blast. These genes were narrowed down to 10 overlapping genes after time-course evaluation and functional analyses. These genes pointed toward signs of repair at day 4 and day 7 post-blast. Our findings suggest that the BOP levels in the study resulted in mild cellular injury to the brain as evidenced by acute neuronal, cerebrovascular, and white matter perturbations that showed signs of resolution. It is unclear whether these perturbations exist at a milder level or normalize completely and will need more investigation. Specific changes in gene expression may be further evaluated to understand the mechanism of blast-induced neurotrauma.
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Affiliation(s)
- Pamela B L Pun
- Combat Care Laboratory, Defence Medical and Environmental Research Institute, DSO National Laboratories Singapore
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