Adrenomedullin Is a Diagnostic and Prognostic Biomarker for Acute Intracerebral Hemorrhage

Hemorrhagic stroke remains an important health challenge. Adrenomedullin (AM) is a vasoactive peptide with an important role in cardiovascular diseases, including stroke. Serum AM and nitrate-nitrite and S-nitroso compounds (NOx) levels were measured and compared between healthy volunteers (n = 50) and acute hemorrhagic stroke patients (n = 64). Blood samples were taken at admission (d0), 24 h later (d1), and after 7 days or at the time of hospital discharge (d7). Neurological severity (NIHSS) and functional prognosis (mRankin) were measured as clinical outcomes. AM levels were higher in stroke patients at all times when compared with healthy controls (p < 0.0001). A receiving operating characteristic curve analysis identified that AM levels at admission > 69.0 pg/mL had a great value as a diagnostic biomarker (area under the curve = 0.89, sensitivity = 80.0%, specificity = 100%). Furthermore, patients with a favorable outcome (NIHSS ≤ 3; mRankin ≤ 2) experienced an increase in AM levels from d0 to d1, and a decrease from d1 to d7, whereas patients with unfavorable outcome had no significant changes over time. NOx levels were lower in patients at d0 (p = 0.04) and d1 (p < 0.001) than in healthy controls. In conclusion, AM levels may constitute a new diagnostic and prognostic biomarker for this disease, and identify AM as a positive mediator for hemorrhagic stroke resolution.

The choroid plexus as a site of damage in hemorrhagic and ischemic stroke and its role in responding to injury

While the impact of hemorrhagic and ischemic strokes on the blood–brain barrier has been extensively studied, the impact of these types of stroke on the choroid plexus, site of the blood-CSF barrier, has received much less attention. The purpose of this review is to examine evidence of choroid plexus injury in clinical and preclinical studies of intraventricular hemorrhage, subarachnoid hemorrhage, intracerebral hemorrhage and ischemic stroke. It then discusses evidence that the choroid plexuses are important in the response to brain injury, with potential roles in limiting damage. The overall aim of the review is to highlight deficiencies in our knowledge on the impact of hemorrhagic and ischemic strokes on the choroid plexus, particularly with reference to intraventricular hemorrhage, and to suggest that a greater understanding of the response of the choroid plexus to stroke may open new avenues for brain protection.

Identification of plasma adrenomedullin as a possible prognostic biomarker for aneurysmal subarachnoid hemorrhage

Increased plasma adrenomedullin levels have been reported in critically ill patients. This study tested the hypothesis that plasma adrenomedullin levels are significantly increased in patients with acute spontaneous aneurysmal subarachnoid hemorrhage, and are predictive of clinical outcomes. Plasma adrenomedullin levels from 120 adult patients with spontaneous aneurysmal subarachnoid hemorrhage and 120 healthy volunteers during the study period were evaluated. Mortality and poor long-term outcome (Glasgow Outcome Scale score of 1-3) at 6 months were recorded. Data showed that circulating plasma adrenomedullin levels significantly increased in patients on admission compared with the volunteers. In patients who died or had poor outcome at 6 months, plasma adrenomedullin levels were significantly higher compared with survivors and patients with good outcome. Plasma adrenomedullin levels on presentation were highly associated with clinical severity assessed using World Federation of Neurological Surgeons score and Fisher score, emerged as the independent risk factor of 6-month mortality and poor outcome, and possessed similar predictive value to World Federation of Neurological Surgeons score and Fisher score based on receiver operating characteristic curves. A combined logistic-regression model did not demonstrate the additive benefit of adrenomedullin to World Federation of Neurological Surgeons score and Fisher score. Thus, higher plasma adrenomedullin levels on presentation are associated with clinical severity and worse outcomes in patients with acute spontaneous aneurysmal subarachnoid hemorrhage.

Plasma levels of adrenomedullin in patients with traumatic brain injury: potential contribution to prognosis

High plasma levels of adrenomedullin have been associated with stroke severity and clinical outcomes. This study aimed to analyze plasma levels of adrenomedullin in traumatic brain injury and their association with prognosis. One hundred and forty-eight acute severe traumatic brain injury and 148 sex- and age-matched healthy controls were recruited in this study. Plasma adrenomedullin concentration was measured by enzyme-linked immunosorbent assay. Unfavorable outcome was defined as Glasgow Outcome Scale score of 1-3. Compared to controls, the patients had significantly higher plasma concentrations of adrenomedullin, which were also highly associated negatively with Glasgow Coma Scale score. Plasma adrenomedullin level was proved to be an independent predictor for 6-month mortality and unfavorable outcome of patients in a multivariate analysis. A receiver operating characteristic curve was configured to show that a baseline plasma adrenomedullin level predicted 6-month mortality and unfavorable outcome of patients with high area under curve. The predictive performance of the plasma adrenomedullin concentration was also similar to that of Glasgow Coma Scale score for the prediction of 6-month mortality and unfavorable outcome of patients. In a combined logistic-regression model, adrenomedullin improved the area under curve of Glasgow Coma Scale score for the prediction of 6-month mortality and unfavorable outcome of patients, but the differences did not appear to be statistically significant. Thus, high plasma levels of adrenomedullin are associated with head trauma severity, and may independently predict long-term clinical outcomes of traumatic brain injury.

Controversies and evolving new mechanisms in subarachnoid hemorrhage

Despite decades of study, subarachnoid hemorrhage (SAH) continues to be a serious and significant health problem in the United States and worldwide. The mechanisms contributing to brain injury after SAH remain unclear. Traditionally, most in vivo research has heavily emphasized the basic mechanisms of SAH over the pathophysiological or morphological changes of delayed cerebral vasospasm after SAH. Unfortunately, the results of clinical trials based on this premise have mostly been disappointing, implicating some other pathophysiological factors, independent of vasospasm, as contributors to poor clinical outcomes. Delayed cerebral vasospasm is no longer the only culprit. In this review, we summarize recent data from both experimental and clinical studies of SAH and discuss the vast array of physiological dysfunctions following SAH that ultimately lead to cell death. Based on the progress in neurobiological understanding of SAH, the terms "early brain injury" and "delayed brain injury" are used according to the temporal progression of SAH-induced brain injury. Additionally, a new concept of the vasculo-neuronal-glia triad model for SAH study is highlighted and presents the challenges and opportunities of this model for future SAH applications.

Blood levels of adrenomedullin on admission predict outcomes after acute intracerebral hemorrhage

Increased plasma adrenomedullin level has been associated with critical illness. This study aimed to investigate the correlations of plasma adrenomedullin concentration with 3-month clinical outcomes and early neurological deterioration of patients with acute intracerebral hemorrhage. One hundred fourteen patients and 112 healthy controls were recruited. Relationships of plasma adrenomedullin concentrations with early neurological deterioration, 3-month mortality and unfavorable outcome (modified Rankin Scale score >2) were evaluated. Plasma adrenomedullin concentrations were increased in patients than in healthy individuals and were highly associated with National Institutes of Health Stroke Scale scores. A multivariate analysis selected plasma adrenomedullin concentration as an independent predictor for 3-month clinical outcomes and early neurological deterioration. A receiver operating characteristic curve analysis showed plasma adrenomedullin concentration predicted 3-month clinical outcomes and early neurological deterioration with high area under curves. The predictive value of adrenomedullin was similar to that of National Institutes of Health Stroke Scale score. In a combined logistic-regression model, adrenomedullin did not improve the predictive value of National Institutes of Health Stroke Scale score. Thus, elevated plasma adrenomedullin concentration is highly associated with 3-month clinical outcomes and early neurological deterioration of patients with acute intracerebral hemorrhage.

Plasma adrenomedullin levels are associated with long-term outcomes of acute ischemic stroke

Plasma adrenomedullin concentration has been found to be enhanced in ischemic stroke. Up to now, little is known about the association of plasma adrenomedullin concentration with clinical outcomes of ischemic stroke. This study recruited 138 patients with ischemic stroke and 138 healthy volunteers. Unfavorable outcome was defined as modified Rankin Scale score >2 at 3 months. Plasma adrenomedullin concentrations were determined by enzyme-linked immunosorbent assay. Plasma adrenomedullin concentrations were statistically significantly higher in patients than in healthy individuals (79.9±27.3pg/mL vs. 36.8±10.4pg/mL; P<0.001). 3-Month mortality was 20.3% (28/138) and sixty-six patients (47.8%) had unfavorable outcome in 3 months. A logistic regression analysis identified plasma adrenomedullin concentration as an independent predictor of 3-month mortality (odds ratio, 1.211; 95% confidence interval, 1.101-1.582; P=0.004) and unfavorable outcome (odds ratio, 1.193; 95% confidence interval, 1.082-1.447; P=0.006). Receiver operating characteristic curve analysis showed that plasma adrenomedullin concentration predicted 3-month mortality (area under curve, 0.806; 95% confidence interval, 0.730-0.868) and unfavorable outcome (area under curve, 0.816; 95% confidence interval, 0.742-0.877) with the high predictive value. Its predictive performance was similar to that of National Institutes of Health Stroke Scale score (P=0.694 or 0.206). Its combined use with National Institutes of Health Stroke Scale score did not improve the predictive value (P=0.236 or 0.590). Thus, adrenomedullin may aid to predict long-term clinical outcomes of patients with ischemic stroke.