ORCID Profile
0000-0002-9874-2947
Current Organisations
University of the Basque Country
,
King's College London
,
University College London
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Publisher: Public Library of Science (PLoS)
Date: 29-03-2017
Publisher: Public Library of Science (PLoS)
Date: 29-11-2016
Publisher: Elsevier BV
Date: 03-2016
Publisher: SAGE Publications
Date: 08-10-2015
Abstract: Remote ischemic postconditioning (RIPostC) is a promising therapeutic intervention whereby brief episodes of ischemia/reperfusion of one organ (limb) mitigate damage in another organ (brain) that has experienced severe hypoxia-ischemia. Our aim was to assess whether RIPostC is protective following cerebral hypoxia-ischemia in a piglet model of neonatal encephalopathy (NE) using magnetic resonance spectroscopy (MRS) biomarkers and immunohistochemistry. After hypoxia-ischemia (HI), 16 Large White female newborn piglets were randomized to: (i) no intervention ( n = 8) (ii) RIPostC – with four, 10-min cycles of bilateral lower limb ischemia/reperfusion immediately after HI ( n = 8). RIPostC reduced the hypoxic-ischemic-induced increase in white matter proton MRS lactate/N acetyl aspartate ( p = 0.005) and increased whole brain phosphorus-31 MRS ATP ( p = 0.039) over the 48 h after HI. Cell death was reduced with RIPostC in the periventricular white matter ( p = 0.03), internal capsule ( p = 0.002) and corpus callosum ( p = 0.021) there was reduced microglial activation in corpus callosum ( p = 0.001) and more surviving oligodendrocytes in corpus callosum ( p = 0.029) and periventricular white matter ( p = 0.001). Changes in gene expression were detected in the white matter at 48 h, including K ATP channel and endothelin A receptor. Immediate RIPostC is a potentially safe and promising brain protective therapy for babies with NE with protection in white but not grey matter.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2015
DOI: 10.1161/STROKEAHA.114.007330
Abstract: In infants with moderate to severe neonatal encephalopathy, whole-body cooling at 33°C to 34°C for 72 hours is standard care with a number needed to treat to prevent a adverse outcome of 6 to 7. The precise brain temperature providing optimal neuroprotection is unknown. After a quantified global cerebral hypoxic-ischemic insult, 28 piglets aged hours were randomized (each group, n=7) to (1) normothermia (38.5°C throughout) or whole-body cooling 2 to 26 hours after insult to (2) 35°C, (3) 33.5°C, or (4) 30°C. At 48 hours after hypoxia-ischemia, delayed cell death (terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling and cleaved caspase 3) and microglial ramification (ionized calcium-binding adapter molecule 1) were evaluated. At 48 hours after hypoxia-ischemia, substantial cerebral injury was found in the normothermia and 30°C hypothermia groups. However, with 35°C and 33.5°C cooling, a clear reduction in delayed cell death and microglial activation was observed in most brain regions ( P .05), with no differences between 35°C and 33.5°C cooling groups. A protective pattern was observed, with U-shaped temperature dependence in delayed cell death in periventricular white matter, caudate nucleus, putamen, hippoc us, and thalamus. A microglial activation pattern was also seen, with inverted U-shaped temperature dependence in periventricular white matter, caudate nucleus, internal capsule, and hippoc us (all P .05). Cooling to 35°C (an absolute drop of 3.5°C as in therapeutic hypothermia protocols) or to 33.5°C provided protection in most brain regions after a cerebral hypoxic-ischemic insult in the newborn piglet. Although the relatively wide therapeutic range of a 3.5°C to 5°C drop in temperature reassured, overcooling (an 8.5°C drop) was clearly detrimental in some brain regions.
Publisher: S. Karger AG
Date: 2017
DOI: 10.1159/000458438
Abstract: The selective α sub /sub -adrenoreceptor agonist dexmedetomidine has shown neuroprotective, analgesic, anti-inflammatory, and sympatholytic properties that may be beneficial in neonatal encephalopathy (NE). As therapeutic hypothermia is only partially effective, adjunct therapies are needed to optimize outcomes. The aim was to assess whether hypothermia + dexmedetomidine treatment augments neuroprotection compared to routine treatment (hypothermia + fentanyl sedation) in a piglet model of NE using magnetic resonance spectroscopy (MRS) biomarkers, which predict outcomes in babies with NE, and immunohistochemistry. After hypoxia-ischaemia (HI), 20 large White male piglets were randomized to: (i) hypothermia + fentanyl with cooling to 33.5°C from 2 to 26 h, or (ii) hypothermia + dexmedetomidine (a loading dose of 2 μg/kg at 10 min followed by 0.028 μg/kg/h for 48 h). Whole-brain phosphorus-31 and regional proton MRS biomarkers were assessed at baseline, 24, and 48 h after HI. At 48 h, cell death was evaluated over 7 brain regions by means of transferase-mediated d-UTP nick end labeling (TUNEL). Dexmedetomidine plasma levels were mainly within the target sedative range of 1 μg/L. In the hypothermia + dexmedetomidine group, there were 6 cardiac arrests (3 fatal) versus 2 (non-fatal) in the hypothermia + fentanyl group. The hypothermia + dexmedetomidine group required more saline ( i /i = 0.005) to maintain blood pressure. Thalamic and white-matter lactate/N-acetylaspartate did not differ between groups ( i /i = 0.66 and i /i = 0.21, respectively) the whole-brain nucleotide triphosphate/exchangeable phosphate pool was similar ( i /i = 0.73) over 48 h. Cell death (TUNEL-positive cells/mm sup /sup ) was higher in the hypothermia + dexmedetomidine group than in the hypothermia + fentanyl group (mean 5.1 vs. 2.3, difference 2.8 [95% CI 0.6-4.9], i /i = 0.036). Hypothermia + dexmedetomidine treatment was associated with adverse cardiovascular events, even within the recommended clinical sedative plasma level these may have been exacerbated by an interaction with either isoflurane or low body temperature. Hypothermia + dexmedetomidine treatment was neurotoxic following HI in our piglet NE model, suggesting that caution is vital if dexmedetomidine is combined with cooling following NE.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Daniel Alonso-Alconada.