Correlation of Adrenomedullin gene expression in peripheral blood leukocytes with severity of ischemic stroke

Quantitative analysis of selected genetic markers of induced brain stroke ischemic tolerance detected in human blood

A brain stroke is a serious disease and the second leading cause of death in the European Union. Carotid stenosis accounts for 15% of all ischemic cerebral strokes. However, there is currently no effective screening for carotid disease. Analysis of the DNA from peripheral blood is increasingly being used for several disease diagnoses. The potentially beneficial therapeutic method of inducing tissue tolerance to ischemia has so far been studied mainly in animal models. The aim of this study is to investigate changes in the gene expression of selected markers of brain ischemia during carotid endarterectomy, considered in this study as an activator of ischemic tolerance. During the carotid endarterectomy, there is a short-term occlusion of the internal carotid artery. Using the RT-qPCR method, we detected changes in the early identified gene markers of brain ischemia (ADM, CDKN1A, GADD45G, IL6, TM4SF1) in peripheral blood during sub lethal cerebral ischemia caused by carotid endarterectomy. Patients underwenting surgical procedure were divided into three groups: asymptomatic, symptomatic, and those who underwent carotid endarterectomy after an acute stroke. The results were compared to a negative/control group. Carotid endarterectomy had an impact on the expression of all monitored biomarkers. We observed statistically significant changes (p value 0.05-0.001) when comparing the groups among themselves, as well as the presence of ischemic tolerance of brain tissue to ischemic attacks. In conclusion, ADM, GADD45G, and TM4SF1 were affected in symptomatic patients, GADD45G and IL6 in acute patients, and CDKN1A and ADM in asymptomatic group after application of carotid endarterectomy.

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.

Adrenomedullin: A vasoactive agent for sporadic and hereditary vascular cognitive impairment

Adrenomedullin (AM) is an endogenous peptide mainly secreted from endothelial cells, which has multiple physiological actions such as anti-inflammation, vasodilation, vascular permeability regulation and angiogenesis. Blood AM levels are upregulated in a variety of pathological states including sepsis, severe COVID-19, acute ischemic stroke and vascular cognitive impairment with white matter changes, likely serving as a compensatory biological defense response against infection and ischemia. AM is currently being tested in clinical trials for ulcerative colitis, Crohn's disease, severe COVID-19 for its anti-inflammatory properties and in ischemic stroke for its additional angiogenic action. AM has been proposed as a therapeutic option for vascular cognitive impairment as its arteriogenic and angiogenic properties are thought to contribute to a slowing of cognitive decline in mice after chronic cerebral hypoperfusion. As AM promotes differentiation of oligodendrocyte precursor cells into mature oligodendrocytes under hypoxic conditions, AM could also be used in the treatment of CADASIL, where reduced oxygen delivery is thought to lead to the death of hypoxia-prone oligodendrocytes. AM therefore holds potential as an innovative therapeutic drug, which may regenerate blood vessels, while controlling inflammation in cerebrovascular diseases.

Polyethylene glycol-conjugated human adrenomedullin as a possible treatment for vascular dementia

Adrenomedullin (AM) is a multifunctional bioactive peptide. Recent studies have shown that AM has protective effects against ischemic brain damage. We recently prepared a long-acting human AM derivative that was conjugated with a 60 kDa polyethylene glycol (PEG-AM), which had an effect similar to that of native AM. In this study, we examined the effect of PEG-AM on four-vessel occlusion model rats, which exhibit vascular dementia. From day 10 to day 14 after surgery, the learning and memory abilities of the rats were examined using a Morris water maze. The rats were treated with a single subcutaneous injection of 1.0 or 10.0 nmol/kg of PEG-AM. PEG-AM treatment reduced the escape latency in the hidden platform test. Furthermore, the treatment increased the time spent in the platform quadrant in the probe test. The data showed that PEG-AM injection prevented memory loss and learning disorders in dose-dependent manner. On day 14, the immunoreactive AM concentration in plasma was 9.749 ± 2.167 pM in the high-dose group (10.0 nmol/kg) and 0.334 ± 0.073 pM in the low-dose group (1.0 nmol/kg). However, even in the low-dose group, a significant effect was observed in both tests. The present data indicate that PEG-AM is a possible therapeutic agent for the treatment of ischemic brain injury or vascular dementia.

Blood transcriptomic biomarker as a surrogate of ischemic brain gene expression

Objectives

Blood biomarkers for cerebral tissue ischemia are lacking. The goal was to identify a blood transcriptomic signature jointly identified in the ischemic brain.

Methods

A nonhuman primate model with middle cerebral artery (MCA) territory infarction was used to study gene expression by microarray during acute ischemic cerebral stroke in the brain and the blood. Brain samples were collected in the infarcted and contralateral non‐infarcted cortex as well as blood samples before and after occlusion. Gene expression was compared between the two brain locations to find differentially expressed genes. The expressions of these genes were then compared in the blood pre‐ and post‐occlusion.

Results

Hierarchical clustering of brain expression data revealed strong independent clustering of ischemic and nonischemic brain samples. The top five enriched, up‐regulated gene sets in the brain were TNF α signaling, apoptosis, P53 pathway, hypoxia, and UV response up. A comparison of differentially expressed genes in the brain and blood revealed a significant overlap of gene expression patterns. Stringent analysis of blood expression data from pre‐ and post‐occlusion samples in each monkey identified nine genes highly differentially expressed in both the brain and the blood. Many of these up‐regulated genes belong to pathways involved in cell death and DNA damage repair.

Interpretation

Common gene expression profile can be identified in the brain and blood and clearly differentiates ischemic from nonischemic conditions. Therefore, specific blood transcriptomic signature may represent a surrogate for brain ischemic gene expression.

Blood biomarkers associated with neurological deterioration in patients with acute penetrating artery territory infarction: A multicenter prospective observational study

Background and purpose

Neurological deterioration in acute penetrating artery territory infarction is unpredictable and associated with unfavorable clinical outcomes. The aim of this prospective study was to clarify the cause of neurological worsening and predict clinical outcomes using blood biomarkers.

Methods

Eight Japanese stroke centers participated. Blood samples were obtained within 24 h (the first sampling) and on day 7 in hospital (the second sampling) in patients with penetrating artery territory infarction, arriving within two days of stroke onset. Symptomatic worsening was defined as a minimum increase of one point on the National Institutes of Health Stroke Scale. Poor outcome was defined as a modified Rankin Scale score of ≥3 at 90 days after ictus.

Results

Of the 89 patients, 25 (28%) had symptomatic worsening, and 25 (28%) had a poor outcome. Although tumor necrosis factor-alpha, high-sensitivity C-reactive protein levels were significantly increased in both groups at the second sampling, soluble lectin-like oxidized low-density lipoprotein receptor-1, CD40 ligand, and pro-adrenomedullin levels were significantly increased and ADAMTS13 activity was decreased in symptomatic worsening patients ( p < 0.05 for all). After multivariate adjustment, a low number of CD34+ cells at the first sampling was an independent predictor of poor outcome (odds ratio, 0.20; 95% confidence interval, 0.04–0.74, p = 0.011, per 1 cell/µl increase).

Conclusions

Blood biomarkers associated with atherosclerotic processes seem to be an indication for symptomatic worsening, and the number of CD34+ cells may help to predict three-month functional outcome in patients with penetrating artery territory infarction.

Lack of adrenomedullin in mouse endothelial cells results in defective angiogenesis, enhanced vascular permeability, less metastasis, and more brain damage

Adrenomedullin (AM) is a vasodilating peptide involved in the regulation of circulatory homeostasis and in the pathophysiology of certain cardiovascular diseases. AM plays critical roles in blood vessels, including regulation of vascular stability and permeability. To elucidate the autocrine/paracrine function of AM in endothelial cells (EC) in vivo, a conditional knockout of AM in EC (AM(EC-KO)) was used. The amount of vascularization of the matrigel implants was lower in AM(EC-KO) mice indicating a defective angiogenesis. Moreover, ablation of AM in EC revealed increased vascular permeability in comparison with wild type (WT) littermates. In addition, AM(EC-KO) lungs exhibited significantly less tumor growth than littermate WT mice using a syngeneic model of metastasis. Furthermore, following middle cerebral artery permanent occlusion, there was a significant infarct size decrease in animals lacking endothelial AM when compared to their WT counterparts. AM is an important regulator of EC function, angiogenesis, tumorigenesis, and brain response to ischemia. Studies of AM should bring novel approaches to the treatment of vascular diseases.

Temporal profiles of blood pressure, circulating nitric oxide, and adrenomedullin as predictors of clinical outcome in acute ischemic stroke patients

Stroke remains an important health and social challenge. The present study investigated whether blood pressure (BP) parameters and circulating levels of nitric oxide metabolites (NOx) and adrenomedullin (AM) may predict clinical outcomes of stroke. Patients (n=76) diagnosed with acute ischemic stroke were admitted to the stroke unit and clinical history data and monitored parameters were recorded. Blood plasma was collected at days 1, 2, and 7 to measure NOx and AM levels. Infarct volume, neurological severity [on the National Institutes of Health Stroke Scale (NIHSS)], and functional prognosis (on the Rankin scale) were measured as clinical outcomes. Patients with higher BP had more severe symptoms (NIHSS >3; P<0.01) and BP variability predicted neurological severity and growth of infarct volume. NOx values were significantly lower in stroke patients than in healthy controls (P<0.01). An increase in NOx levels from day 1 to day 2 was beneficial for the patients as measured by NIHSS at 7 days and 3 months, and by Rankin at 3 months [odds ratio (OR), 0.91] whereas a steep increase from day 2 to day 7 was detrimental and associated with an increase in infarct volume (OR, 35.3). AM levels were significantly higher in patients at day 1 and 2 than in healthy individuals (P<0.01) and these levels returned to normal at day 7. Patients with high AM levels at day 2 had significantly higher NIHSS scores measured at day 1 (P<0.05) and 7 (P<0.01). A receiving operating characteristic curve analysis identified that AM levels at day 2 of >522.13 pg/ml predicted increased neurological severity at day 7 (area under the curve=0.721). Multivariate logistic regression indicated that AM levels at day 2 predicted increased neurological severity at 7 days and at 3 months. BP parameters and changing levels for NOx and AM predicted long-term clinical outcomes as measured by infarct volume, neurological severity scale, and functional prognosis.

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.

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.