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Andersen HB, Andersen M, Bennedsgaard K, Kerrn-Jespersen S, Kyng KJ, Holm IE, Henriksen TB. No Differences in Cerebral Immunohistochemical Markers following Remote Ischemic Postconditioning in Newborn Piglets with Hypoxia-Ischemia. Neuropediatrics 2022; 53:423-431. [PMID: 35777661 PMCID: PMC9643070 DOI: 10.1055/a-1889-8544] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 06/02/2022] [Indexed: 10/17/2022]
Abstract
BACKGROUND Despite therapeutic hypothermia, neonates with hypoxic-ischemic encephalopathy still develop neurological disabilities. We have previously investigated neuroprotection by remote ischemic postconditioning (RIPC) in newborn piglets following hypoxia-ischemia (HI). The aim of this study was to further investigate potential effects of RIPC on cerebral immunohistochemical markers related to edema, apoptosis, and angiogenesis. METHODS Brain expression of aquaporin 4, caspase-3, B-cell lymphoma 2, and vascular endothelial growth factor was analyzed by immunohistochemistry in 23 piglets, randomly selected from a larger study of RIPC after HI. Twenty animals were subjected to 45 minutes of HI and randomized to treatment with and without RIPC, while three animals were randomized to sham procedures. RIPC was conducted by four conditioning cycles of 5-minute ischemia and reperfusion. Piglets were euthanized 72 hours after the HI insult. RESULTS Piglets subjected to HI treated with and without RIPC were similar at baseline and following the HI insult. However, piglets randomized to HI alone had longer duration of low blood pressure during the insult. We found no differences in the brain expression of the immunohistochemical markers in any regions of interest or the whole brain between the two HI groups. CONCLUSION RIPC did not influence brain expression of markers related to edema, apoptosis, or angiogenesis in newborn piglets at 72 hours after HI. These results support previous findings of limited neuroprotective effect by this RIPC protocol. Our results may have been affected by the time of assessment, use of fentanyl as anesthetic, or limitations related to our immunohistochemical methods.
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Affiliation(s)
- Hannah B. Andersen
- Department of Paediatrics and Adolescent Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Mads Andersen
- Department of Paediatrics and Adolescent Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Kristine Bennedsgaard
- Department of Paediatrics and Adolescent Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Sigrid Kerrn-Jespersen
- Department of Paediatrics and Adolescent Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Kasper J. Kyng
- Department of Paediatrics and Adolescent Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Ida E. Holm
- Department of Pathology, Randers Regional Hospital, Randers, Denmark
| | - Tine B. Henriksen
- Department of Paediatrics and Adolescent Medicine, Aarhus University Hospital, Aarhus, Denmark
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Andelius TCK, Henriksen TB, Kousholt BS, Kyng KJ. Remote ischemic postconditioning for neuroprotection after newborn hypoxia-ischemia: systematic review of preclinical studies. Pediatr Res 2022; 91:1654-1661. [PMID: 34282277 DOI: 10.1038/s41390-021-01656-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 06/12/2021] [Accepted: 06/17/2021] [Indexed: 02/05/2023]
Abstract
BACKGROUND Hypoxic-ischemic encephalopathy (HIE) is a major contributor to death and disability worldwide. Remote ischemic postconditioning (RIPC) may offer neuroprotection but has only been tested in preclinical models. Various preclinical models with different assessments of outcomes complicate interpretation. The objective of this systematic review was to determine the neuroprotective effect of RIPC in animal models of HIE. METHODS The protocol was preregistered at The International Prospective Register of Systematic Reviews (PROSPERO) (CRD42020205944). Literature was searched in PubMed, Embase, and Web of Science (April 2020). A formal meta-analysis was impossible due to heterogeneity and a descriptive synthesis was performed. RESULTS Thirty-two papers were screened, and five papers were included in the analysis. These included three piglet studies and two rat studies. A broad range of outcome measures was assessed, with inconsistent results. RIPC improved brain lactate/N-acetylaspartate ratios in two piglet studies, suggesting a limited metabolic effect, while most other outcomes assessed were equally likely to improve or not. CONCLUSIONS There is a lack of evidence to evaluate the neuroprotective effect of RIPC in HIE. Additional studies should aim to standardize methodology and outcome acquisition focusing on clinically relevant outcomes. Future studies should address the optimal timing and duration of RIPC and the combination with therapeutic hypothermia. IMPACT This systematic review summarizes five preclinical studies that reported inconsistent effects of RIPC as a neuroprotective intervention after hypoxia-ischemia. The heterogeneity of hypoxia-ischemia animal models employed, mode of postconditioning, and diverse outcomes assessed at varying times means the key message is that no clear conclusions on effect can be drawn. This review highlights the need for future studies to be designed with standardized methodology and common clinically relevant outcomes in models with documented translatability to the human condition.
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Affiliation(s)
- Ted C K Andelius
- Department of Paediatrics, Aarhus University Hospital, Aarhus N, Denmark
| | - Tine B Henriksen
- Department of Paediatrics, Aarhus University Hospital, Aarhus N, Denmark
| | - Birgitte S Kousholt
- Aarhus University Group for Understanding Systematic Reviews and Metaanalyses in Translational Preclinical Science, Department of Clinical Medicine, Aarhus University, Aarhus N, Denmark
| | - Kasper J Kyng
- Department of Paediatrics, Aarhus University Hospital, Aarhus N, Denmark.
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Kyng KJ, Wellmann S, Lehnerer V, Hansen LH, Kuhle J, Henriksen TB. Neurofilament Light Chain serum levels after Hypoxia-Ischemia in a newborn piglet model. Front Pediatr 2022; 10:1068380. [PMID: 36699314 PMCID: PMC9869944 DOI: 10.3389/fped.2022.1068380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 12/16/2022] [Indexed: 01/12/2023] Open
Abstract
AIM Neurofilament light Chain (NfL) is a promising brain injury biomarker which may assist diagnosis and prognostication in hypoxic-ischemic encephalopathy (HIE). The aim of this study was to investigate serum NfL levels after hypoxia-ischemia (HI) in a newborn piglet model. Second, to characterize the influence of sex, weight, and treatment with remote ischemic postconditioning (RIPC) on NfL and the correlation between NfL, brain imaging and histologic brain injury. METHODS We used serum from 48 newborn piglets of both sexes subjected to 45 min of global HI, and 4 sham piglets. Blood was collected pre-HI, 2 h post-HI and 72 h post-HI. NfL was measured by single-molecule array (Simoa™). We analysed the temporal profile of NfL after HI, and correlations between NfL, magnetic resonance spectroscopy brain Lac/NAA ratios and histologic brain injury 72 h after HI. RESULTS Median (IQR) NfL levels were: pre-HI: 66 pg/ml (45-87), 2 h post-HI: 105 pg/ml (77-140), and 72 h post-HI: 380 pg/ml (202-552). The increase in NfL after HI was statistically significant (p < 0.0001, mixed-effects ANOVA). Median NfL levels in sham animals were 41.4 pg/ml at baseline and 92.4 pg/ml at 72 h (p = 0.11, paired t-test). Neither sex, nor treatment with RIPC influenced NfL levels. Weight had a small, not biologically important, influence. NfL levels at 72 h were moderately correlated with histologic brain injury and brain Lac/NAA ratios. NfL 72 h post-HI > 330 pg/ml had a sensitivity of 89% (95% CI, 57%-99%) and a specificity of 52% (95% CI, 34%-69%) for predicting basal ganglia Lac/NAA ratio in the highest quartile. NfL 72 h post-HI > 445 pg/ml had a sensitivity of 90% (95% CI, 60%-99%) and a specificity of 74% (95% CI, 58%-86%) for predicting cortical brain histopathology injury in the highest quartile. CONCLUSION NfL increased after HI, with the largest values at 72 h post-HI. Early NfL was sensitive but not very specific, whereas NfL at 72 h was both highly sensitive and specific for exposure to moderate-severe HI in this model of HI-induced brain injury. This was supported by a moderate correlation of NfL at 72 h with brain Lac/NAA ratio and histopathology.
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Affiliation(s)
- Kasper Jacobsen Kyng
- Aarhus University Hospital and Aarhus University, Department of Pediatrics and Adolescent Medicine and Department of Clinical Medicine, Aarhus, Denmark
| | - Sven Wellmann
- Department of Neonatology, University Children's Hospital Regensburg (KUNO), Hospital St. Hedwig of the Order of St. John, University of Regensburg, Regensburg, Germany
| | - Verena Lehnerer
- Department of Neonatology, University Children's Hospital Regensburg (KUNO), Hospital St. Hedwig of the Order of St. John, University of Regensburg, Regensburg, Germany
| | - Lærke Hjøllund Hansen
- Aarhus University Hospital and Aarhus University, Department of Pediatrics and Adolescent Medicine and Department of Clinical Medicine, Aarhus, Denmark
| | - Jens Kuhle
- Neurologic Clinic and Policlinic, MS Center and Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), Departments of Biomedicine and Clinical Research, University Hospital Basel, Basel, Switzerland
| | - Tine Brink Henriksen
- Aarhus University Hospital and Aarhus University, Department of Pediatrics and Adolescent Medicine and Department of Clinical Medicine, Aarhus, Denmark
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Kerrn-Jespersen S, Andersen M, Bennedsgaard K, Andelius TCK, Pedersen M, Kyng KJ, Henriksen TB. Remote ischemic postconditioning increased cerebral blood flow and oxygenation assessed by magnetic resonance imaging in newborn piglets after hypoxia-ischemia. Front Pediatr 2022; 10:933962. [PMID: 36245727 PMCID: PMC9559709 DOI: 10.3389/fped.2022.933962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 09/09/2022] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND We have previously investigated neurological outcomes following remote ischemic postconditioning (RIPC) in a newborn piglet model of hypoxic-ischemic encephalopathy. The aim of this study was to further investigate potential mechanisms of neuroprotection by comparing newborn piglets subjected to global hypoxia-ischemia (HI) treated with and without RIPC with regards to measures of cerebral blood flow and oxygenation assessed by functional magnetic resonance imaging. MATERIALS AND METHODS A total of 50 piglets were subjected to 45 min global HI and randomized to either no treatment or RIPC treatment. Magnetic resonance imaging was performed 72 h after the HI insult with perfusion-weighted (arterial spin labeling, ASL) and oxygenation-weighted (blood-oxygen-level-dependent, BOLD) sequences in the whole brain, basal ganglia, thalamus, and cortex. Four sham animals received anesthesia and mechanical ventilation only. RESULTS Piglets treated with RIPC had higher measures of cerebral blood flow in all regions of interest and the whole brain (mean difference: 2.6 ml/100 g/min, 95% CI: 0.1; 5.2) compared with the untreated controls. They also had higher BOLD values in the basal ganglia and the whole brain (mean difference: 4.2 T2*, 95% CI: 0.4; 7.9). Measures were similar between piglets treated with RIPC and sham animals. CONCLUSION Piglets treated with RIPC had higher measures of cerebral blood flow and oxygenation assessed by magnetic resonance imaging in the whole brain and several regions of interest compared with untreated controls 72 h after the HI insult. Whether this reflects a potential neuroprotective mechanism of RIPC requires further study.
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Affiliation(s)
- Sigrid Kerrn-Jespersen
- Department of Paediatrics and Adolescent Medicine, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Mads Andersen
- Department of Paediatrics and Adolescent Medicine, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Kristine Bennedsgaard
- Department of Paediatrics and Adolescent Medicine, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Ted Carl Kejlberg Andelius
- Department of Paediatrics and Adolescent Medicine, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Michael Pedersen
- Comparative Medicine Laboratory, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Kasper Jacobsen Kyng
- Department of Paediatrics and Adolescent Medicine, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Tine Brink Henriksen
- Department of Paediatrics and Adolescent Medicine, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
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Andelius TCK, Pedersen MV, Andersen HB, Andersen M, Hjortdal VE, Pedersen M, Ringgaard S, Hansen LH, Henriksen TB, Kyng KJ. No Added Neuroprotective Effect of Remote Ischemic Postconditioning and Therapeutic Hypothermia After Mild Hypoxia-Ischemia in a Piglet Model. Front Pediatr 2020; 8:299. [PMID: 32676486 PMCID: PMC7333529 DOI: 10.3389/fped.2020.00299] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 05/11/2020] [Indexed: 01/26/2023] Open
Abstract
Introduction: Hypoxic ischemic encephalopathy (HIE) is a major cause of death and disability in children worldwide. Apart from supportive care, the only established treatment for HIE is therapeutic hypothermia (TH). As TH is only partly neuroprotective, there is a need for additional therapies. Intermittent periods of limb ischemia, called remote ischemic postconditioning (RIPC), have been shown to be neuroprotective after HIE in rats and piglets. However, it is unknown whether RIPC adds to the effect of TH. We tested the neuroprotective effect of RIPC with TH compared to TH alone using magnetic resonance imaging and spectroscopy (MRI/MRS) in a piglet HIE model. Methods: Thirty-two male and female piglets were subjected to 45-min global hypoxia-ischemia (HI). Twenty-six animals were randomized to TH or RIPC plus TH; six animals received supportive care only. TH was induced through whole-body cooling. RIPC was induced 1 h after HI by four cycles of 5 min of ischemia and 5 min of reperfusion in both hind limbs. Primary outcome was Lac/NAA ratio at 24 h measured by MRS. Secondary outcomes were NAA/Cr, diffusion-weighted imaging (DWI), arterial spin labeling, aEGG score, and blood oxygen dependent (BOLD) signal measured by MRI/MRS at 6, 12, and 24 h after the hypoxic-ischemic insult. Results: All groups were subjected to a comparable but mild insult. No difference was found between the two intervention groups in Lac/NAA ratio, NAA/Cr ratio, DWI, arterial spin labeling, or BOLD signal. NAA/Cr ratio at 24 h was higher in the two intervention groups compared to supportive care only. There was no difference in aEEG score between the three groups. Conclusion: Treatment with RIPC resulted in no additional neuroprotection when combined with TH. However, insult severity was mild and only evaluated at 24 h after HI with a short MRS echo time. In future studies more subtle neurological effects may be detected with increased MRS echo time and post mortem investigations, such as brain histology. Thus, the possible neuroprotective effect of RIPC needs further evaluation.
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Affiliation(s)
| | - Mette V. Pedersen
- Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark
| | | | - Mads Andersen
- Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark
| | - Vibeke E. Hjortdal
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
| | - Michael Pedersen
- Comparative Medicine Lab, Aarhus University Hospital, Aarhus, Denmark
| | | | - Lærke H. Hansen
- Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark
| | - Tine B. Henriksen
- Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark
| | - Kasper J. Kyng
- Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark
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