Abstract 12650: Activity of Serum Angiotensin Converting Enzyme 2 is Decreased During Acute Ischemic Stroke in Humans

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Douglas M Bennion ◽  
Christian A Rosado ◽  
Emily H Haltigan ◽  
Colin Sumners ◽  
Michael F Waters
Keyword(s):  
Enzyme Activity ◽  
Ischemic Stroke ◽  
Angiotensin Converting Enzyme ◽  
Acute Ischemic Stroke ◽  
Converting Enzyme ◽  
Serum Samples ◽  
Necrosis Factor Alpha ◽  
Angiotensin Converting Enzyme 2 ◽  
Post Stroke ◽  
Rebound Increase

Introduction: The expression and activity of angiotensin converting enzyme 2 (ACE2), a cardio and neuro-protective carboxypeptidase, has recently been shown to be dynamically altered during and after stroke in animal models. Hypothesis: The aim of this study was to characterize the previously unexplored changes in activity of ACE2 in the serum of patients experiencing acute ischemic stroke. Methods: Serum samples were obtained from patients presenting with acute ischemic stroke (n=20) and again at three days post-stroke and enzyme activity levels were analyzed by fluorometric assay and compared to levels from non-stroke control patients (n=20). Results: Ischemic stroke resulted in a significant decrease in serum ACE2 at an average of 3.5 hours after stroke, which was followed by a rebound increase by three days later (Fig 1). ACE activity was also significantly decreased following stroke, but without rebound increases. Tumor necrosis factor-alpha converting enzyme activity was not significantly different from control. ACE2 activity was negatively correlated with systolic blood pressure (SBP) among stroke patients (Fig 2), while activity was positively correlated with SBP among a cohort of healthy young adults (n=16). Conclusions: The characterization of the dynamic and novel changes in serum ACE2 activity in human stroke, which follow observations from preclinical studies, along with the demonstration of a negative association with SBP, provides new insight for the development of therapies that target this protective system in the context of ischemic stroke. Data are mean ± SEM. RFU: relative fluorescence units; *p<0.001 vs. control; †p<0.05 vs. 4h post stroke.

Abstract T P228: Ischemic Stroke Results in Increased Activity of the Neuroprotective Angiotensin Converting Enzyme 2 in Rat Brain and Serum

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Douglas M Bennion ◽  
Emily Haltigan ◽  
Alexander J Irwin ◽  
Daniel L Purich ◽  
Colin Sumners
Keyword(s):  
Cerebral Cortex ◽  
Ischemic Stroke ◽  
Angiotensin Converting Enzyme ◽  
Rat Cerebral Cortex ◽  
Mrna Levels ◽  
Converting Enzyme ◽  
Stroke Treatment ◽  
Angiotensin Converting Enzyme 2 ◽  
Post Stroke ◽  
Rebound Increase

Background: Recent studies show that pharmacological induction of the angiotensin converting enzyme 2/angiotensin-(1-7)/mas [ACE2-Ang-(1-7)-Mas] axis, a protective pathway of the renin angiotensin system, elicits neuroprotection in ischemic stroke. However, endogenous levels and activity of the components of this axis in the brain and serum following stroke are not well established. Here, we assessed the post-stroke activity and expression of ACE2 in rat cerebral cortex and serum after ischemic stroke in rats, in the absence or presence of an ACE2 activator. Methods: Sprague Dawley rats underwent sham surgery or endothelin-1-induced middle cerebral artery occlusion (ET-1 MCAO). Activity of ACE2 was analyzed within serum and cerebral cortical tissue samples using a fluorometric assay, and mRNA levels were assessed by qRT-PCR. In an additional experiment, rats received daily intraperitoneal administration of diminazene aceturate (DIZE), a putative ACE2 activator, or vehicle after ET-1 MCAO. Data are normalized to corresponding control values and expressed as means ± SEM with a significance of p<0.05. Results: ACE2 activity levels were significantly increased in ischemic brain cortex at 4, 12, and 24 h after a stroke (4h: 237.1±46.1%; 12h: 212.4±12.8%; 24h: 191.6±19.1%) versus rats with sham strokes. Paradoxically, there was a significant decrease in ACE2 mRNA levels in the ischemic cortex at 24h (0.71±0.1) compared to shams (1.0±0.08). After decreasing in activity at 4h after stroke, serum ACE2 activity was increased at 24h in stroked rats (96.08±9.4%) versus shams (70.80±7.1%). Post-stroke treatment with DIZE (7.5 mg/kg) resulted in significantly increased ACE2 activity in serum (213.7±49.8%) versus controls, two days following stroke. Conclusions: Activity of the protective enzyme ACE2 is increased in rat cerebral cortex following stroke, with a rebound increase in serum activity. Post-stroke treatment with an ACE2 activator resulted in significantly increased ACE2 activity in serum. These results suggest that stroke therapeutics designed to target the ACE2/Ang-(1-7)/Mas axis may act in synergy with endogenous changes in the acute post-stroke setting, lending promise to their further study as potential neuroprotective agents.

scholarly journals Activation of the Neuroprotective Angiotensin-Converting Enzyme 2 in Rat Ischemic Stroke

Hypertension ◽  
2015 ◽  
Vol 66 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Douglas M. Bennion ◽  
Emily A. Haltigan ◽  
Alexander J. Irwin ◽  
Lauren L. Donnangelo ◽  
Robert W. Regenhardt ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Angiotensin Converting Enzyme ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme 2

Urinary ACE2 in healthy adults and patients with uncomplicated type 1 diabetes

2014 ◽  
Vol 92 (8) ◽  
pp. 703-706 ◽  
Author(s):  
David Z.I. Cherney ◽  
Fengxia Xiao ◽  
Joseph Zimpelmann ◽  
Ronnie L.H. Har ◽  
Vesta Lai ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Enzyme Activity ◽  
Angiotensin Converting Enzyme ◽  
Functional Role ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme 2 ◽  
Protein Levels ◽  
Clinical Complications

Angiotensin-converting enzyme 2 (ACE2) is expressed in the kidney and may be renoprotective. We determined whether urinary ACE2 enzyme activity and protein levels (ELISA), as well as angiotensinogen and ACE, are elevated during clamped euglycemia (4–6 mmol·L–1) in patients with uncomplicated type 1 diabetes (T1D, n = 58) compared with normoglycemic controls (n = 21). We also measured the effect of clamped hyperglycemia (9–11 mmol·L–1) on each urinary factor in T1D patients. Urinary ACE2 activity and protein levels were higher during clamped euglycemia in T1D compared with the controls (p < 0.0001). In contrast, urinary angiotensinogen levels (p = 0.27) and ACE excretion (p = 0.68) did not differ. In response to clamped hyperglycemia in T1D, urinary ACE2 protein decreased (p < 0.0001), whereas urinary ACE2 activity as well as angiotensinogen and ACE levels remained unchanged. Urinary ACE2 activity and protein expression are increased in T1D patients prior to the onset of clinical complications. Further work is required to determine the functional role of urinary ACE2 in early T1D.

Abstract TP102: Human Placental Mesenchymal Stem Cells Derived Exosome-Angiotensin Converting Enzyme-2 Dependent Protection in Ischemic Stroke Injury

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Mansoureh Barzegar ◽  
Yuping Wang ◽  
Jungmi W. Yun ◽  
Oleg Chernyshev ◽  
Roger Kelley ◽  
...  
Keyword(s):  
Stem Cells ◽  
Blood Flow ◽  
Mesenchymal Stem Cells ◽  
Ischemic Stroke ◽  
Angiotensin Converting Enzyme ◽  
Tissue Injury ◽  
Ischemia Reperfusion ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme 2 ◽  
Placental Mesenchymal Stem Cells

Following thrombolytic therapy for stroke, ischemia/reperfusion (I/R) mediated inflammation often disrupts the blood brain barrier (BBB). This can enhance expression of endothelial adhesion markers and perturb normal blood flow regulation. Proposed benefits of stem cell therapy (SCT) in stroke, besides long-term trans-differentiation into neural cells, include secretion of protective factors, which partly depends on exosomes released by stem cells. We evaluated human placenta mesenchymal stem cells (hPMSC) as potential ameliorative SCT in an acute ischemic stroke model. We hypothesize that hPMSC would achieve site-specific suppression of post-ischemic immune cell transmigration, preservation of the BBB and maintenance of blood flow via ‘paracrine’ signaling pathways in acute stroke injury.We found that intraperitoneal (IP) administration of hPMSC at the time of reperfusion, using the middle cerebral artery occlusion (MCAO)/reperfusion model, produced significant protection ( p =0.0001) of the ipsilateral hemisphere. We also demonstrated that hPMSC-treated MCAO mice exhibited significantly greater neurological recovery ( p <0.0001) compared to untreated MCAO, an effect which was accompanied by significant restoration of blood flow ( p <0.01) to the MCAO-stressed brains. Using Evans Blue dye assay, we also observed significant ( p =0.004) improvement of BBB integrity in ipsilateral hemispheres of hPMSC-treated mice vs MCAO controls. Furthermore, we determined that hPMSC-derived exosomes contribute to paracrine based protection of hPMSC in MCAO model. Importantly, we found that hPMSC/exosome protection is mediated partly by the function of angiotensin converting enzyme 2 (ACE2). To evaluate the contribution of ACE2 in protection of the brain after ischemic stroke, we first demonstrated that hPMSC and their exosomes express ACE2. Second, mice injected with hPMSC which had been pre-treated with the specific ACE2 inhibitor (10μM) MLN-4760, showed tissue injury and neurological behavior similar to that seen in untreated MCAO.We conclude that pleiotropic factors associated with hPMSC administration can have a favorable impact on blood flow, BBB integrity potentially alleviating the detrimental effects of ischemic stroke.

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