adrenomedullin and Brain-Edema

Traumatic brain injury (TBI) is a devastating neurologic injury and remains a major cause of death in the world. Secondary injury after TBI is associated with long-term disability in patients with TBI. This study evaluated adrenomedullin (AM) on secondary injury and neurologic functional outcome in rats after TBI.. Forty-eight Sprague Dawley rats were randomly assigned into 3 groups: sham, TBI, and TBI with AM groups. TBI was induced by fluid percussion injury, and AM was intravenously injected. Neurologic function was examined at 2, 3, and 7 days after TBI. Enzyme-linked immunosorbent assay was used to test tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-8 levels in the brain. Brain edema and blood-brain barrier (BBB) permeability in brain tissue were tested. Western blot was used to examine the expression of aquaporin-4, phosphorylated myosin light-chain, and cleaved caspase-3. Terminal deoxynucleotidyl transferase dUTP nick end labeling was used to test the apoptosis.. Compared with the sham group, TNF-α, IL-1β, and IL-6 levels, brain edema, BBB permeability, neurologic examination scores, terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells, and expression of aquaporin-4, phosphorylated myosin light-chain, and cleaved caspase-3 significantly increased in the TBI group. AM treatment significantly inhibited TBI-induced effects.. AM can improve neurologic function and ameliorate brain injury in rats with TBI. AM exerts its neuroprotective effect via its anti-inflammatory and antiapoptotic effect.

Topics: Adrenomedullin; Animals; Apoptosis; Blood-Brain Barrier; Brain Diseases; Brain Edema; Brain Injuries, Traumatic; Neurologic Examination; Neuroprotective Agents; Nociception; Posture; Rats, Sprague-Dawley; Reaction Time; Walking

Recent studies suggest the protective effects of adrenomedullin (AM) on ischemic brain damage. The present study was aimed at investigating the effects of AM and its receptor antagonist, AM₂₂₋₅₂, on ischemia-induced cerebral edema and brain swelling in rats using magnetic resonance imaging. Rats were subjected to 60 min of middle cerebral artery occlusion (MCAO) followed by reperfusion. Intravenous injection of AM (1.0 μg/kg), AM₂₂₋₅₂ (1.0 μg/kg), or saline was made before MCAO. Effects of AM injection just after reperfusion were also investigated. One day after ischemia, increases in T₂-weighted signals in the brain were clearly observed. Total edema volume, as well as brain swelling, was greatly and significantly reduced by pre-treatment of AM (reduced by 53%). Extent of brain swelling was significantly correlated with the volume of cerebral edema. The protective effect of AM against edema was more clearly observed in the cerebral cortex (reduced by 63%) than the striatum (reduced by 31%). Increased T₂ relaxation time in the cortex was recovered partially by pre-treatment of AM. Post-treatment of AM had no effects. Pre-treatment of AM₂₂₋₅₂ tended to exacerbate the edema. In another line of experiment, cocktail administration of AM with melatonin, a pineal product having neuroprotective potential as a free radical scavenger, failed to enhance the protective effects of AM alone. The present study clearly suggests the prophylactic effects of AM against cerebral edema, especially the cortical edema, in a rat stroke model.

Topics: Adrenomedullin; Animals; Brain; Brain Edema; Infarction, Middle Cerebral Artery; Magnetic Resonance Imaging; Male; Melatonin; Peptide Fragments; Rats; Rats, Wistar; Reperfusion Injury; Vasodilator Agents

Vascular endothelial growth factor (VEGF) is a potent mediator of vascular permeability. VEGF inhibition reduces edema and tumor burden in some patients with malignant glioma, whereas others show no response. The role of VEGF expression in edema production and the relationship to survival is not well understood.. Using DNA microarray analysis, we examined VEGF and related gene expression in 71 newly diagnosed malignant gliomas and analyzed the relationship to edema and survival.. VEGF expression was predictive of survival in tumors with little or no edema [Cox proportional hazard model, 6.88; 95% confidence interval (95% CI), 2.61-18.1; P<0.0001], but not in tumors with extensive edema. The expression of several proangiogenic genes, including adrenomedullin (correlation coefficient, 0.80), hypoxia-inducible factor-1A (0.51), and angiopoietin-2 (0.44), was correlated with VEGF expression (all with P<0.0001), whereas that of several antiangiogenic genes was inversely correlated. The expression of six genes was increased greater than 3-fold in edematous versus nonedematous tumors in the absence of increased VEGF expression. The most increased, neuronal pentraxin 2 (NPTX2, 7-fold change), was predictive of survival in tumors with the highest levels of edema, in contrast to VEGF (hazard ratio, 2.73; 95% CI, 1.49-5.02; P=0.049). NPTX2 was tightly correlated with expression of the water channel aquaporin-3 (0.74, P<0.0001). These results suggest that there are both VEGF-dependent and VEGF-independent pathways of edema production in gliomas and may explain why edema is not reduced in some patients following anti-VEGF treatment.

Topics: Adrenomedullin; Angiopoietin-2; Aquaporin 3; Brain Edema; Brain Neoplasms; C-Reactive Protein; Gene Expression; Glioma; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Nerve Tissue Proteins; Oligonucleotide Array Sequence Analysis; Prognosis; Survival; Vascular Endothelial Growth Factor A

Adrenomedullin is a recently discovered 52-amino-acid peptide that is a potent vasodilator. Infusion of adrenomedullin increases regional cerebral blood flow and reduces infarct volume after vascular occlusion in rats. Adrenomedullin may represent an endogenous neuroprotectant since it is increased after focal brain ischemia. Cerebral hypoperfusion is present after traumatic brain injury (TBI) in children. We hypothesized that adrenomedullin levels would be increased in children with severe TBI. Total adrenomedullin concentrations were measured using a radioimmunometric assay. Thirty-six samples of ventricular cerebrospinal fluid (CSF) from 10 pediatric patients were collected during the first 10 days after severe TBI (GCS < 8). Control CSF was obtained from 5 children undergoing lumbar puncture, who had normal CSF parameters and no evidence of central nervous system infection. Patients underwent standard neuro-intensive care, including cerebrospinal fluid drainage. Data were analyzed using a univariate regression model. Adrenomedullin concentration was markedly elevated in CSF of children following TBI versus control (mean level 10.65 vs 1.51 fmol/ml, p = 0.006). All 36 case samples had an adrenomedullin concentration above the median value for the controls (1.52 fmol/ml). We conclude adrenomedullin is elevated in the CSF of children following severe TBI. We speculate that it participates in the endogenous response to cerebral hypoperfusion after TBI.

Topics: Adrenomedullin; Brain; Brain Concussion; Brain Edema; Brain Ischemia; Child; Child, Preschool; Female; Humans; Infant; Male; Peptides; Prognosis; Reference Values; Vasodilation