International Journal of Neuroscience
ISSN: 0020-7454 (Print) 1543-5245 (Online) Journal homepage: http://www.tandfonline.com/loi/ines20
Atorvastatin treatment is associated with increased BDNF level and improved functional recovery after atherothrombotic stroke Jingmiao Zhang, Xiali Mu, Dane A Breker, Ying Li, Zongliang Gao & Yonglu Huang To cite this article: Jingmiao Zhang, Xiali Mu, Dane A Breker, Ying Li, Zongliang Gao & Yonglu Huang (2016): Atorvastatin treatment is associated with increased BDNF level and improved functional recovery after atherothrombotic stroke, International Journal of Neuroscience, DOI: 10.3109/00207454.2016.1146882 To link to this article: http://dx.doi.org/10.3109/00207454.2016.1146882
Accepted author version posted online: 27 Jan 2016.
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Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ines20 Download by: [NUS National University of Singapore]
Date: 28 January 2016, At: 19:52
Publisher: Taylor & Francis Journal: International Journal of Neuroscience DOI: http://dx.doi.org/10.3109/00207454.2016.1146882
Atorvastatin treatment is associated with increased BDNF level and improved functional recovery after atherothrombotic stroke Jingmiao Zhang1, Xiali Mu1, Dane A Breker2, Ying Li1, Zongliang Gao1, Yonglu Huang1,* Downloaded by [NUS National University of Singapore] at 19:52 28 January 2016
1
The Second Affiliated Hospital of Anhui Medical University, Department of Neurology,
Hefei, Anhui 230601, P. R. China, 2
University of Michigan, Department of Neurology, Ann Arbor, Michigan 48109, USA
*Correspondence to: Yonglu Huang, MD/PhD, Department of Neurology, The Second Affiliated Hospital of Anhui Medical University, 678 Furong Road, Hefei 230601, P. R. China; Tel.: 86-551-6386-9586; Fax: 86-551-6386-9400; Email: [email protected]
Abstract Back ground: Statins have a positive impact on ischemic stroke outcome. It has been reported that Statin have neuroprotective function after ischemic stroke in addition to lipid-lowering effect in animal model. However, the neuroprotective function of statin after stroke has not been confirmed in clinical studies. The aim of present study was to evaluate in a clinical model if statins induce neuroprotection after stroke. We therefore assessed serum BDNF levels and functional recovery in atherothrombotic stroke patients and investigated their relationship with atorvastatin treatment. Methods: 78 patients with atherothrombotic stroke were enrolled and randomly assigned to atorvastatin treatment
1
group or placebo control group. Neurological function after stroke was assessed with the National Institutes of Health Stroke Scale (NIHSS), Modified Rankin Scale (mRS) and Barthel Index (BI). Serum BDNF levels were both measured at 1 day and 6 weeks after stroke. Linear regression was used to assess the association between BDNF levels and neurological function scores. Results: The mRS and BI were markedly improved in the
Downloaded by [NUS National University of Singapore] at 19:52 28 January 2016
atorvastatin group when compared to placebo at 6 weeks after stroke. The serum BDNF levels in atorvastatin group were significantly elevated by 6 weeks after stroke and higher than the BDNF levels in controls. In addition, the serum BDNF levels significantly correlated with mRS and BI after stroke. Our results demonstrated that atorvastatin treatment was associated with increased BDNF level and improved functional recovery after atherothrombotic stroke. Conclusion: This study indicates that atorvastatin-related elevation in BDNF level may promote functional recovery in stroke patients. Keywords: Stroke, BDNF, atorvastatin, NIHSS, mRS, BI
2
Introduction Stroke has a high incidence of morbidity and mortality and leads to substantial burden for society and patients’ families. Recent studies have shown that stroke recurrence may be reduced by statins [1]. Statins are a class of HMG-CoA (3hydroxy-3-methyl-Glutaryl-coenzyme A) reductase inhibitors that prevent cholesterol
Downloaded by [NUS National University of Singapore] at 19:52 28 January 2016
synthesis. It has also been reported that statins have a positive impact on acute ischemic stroke outcome in addition to the lipid lowering effects [2,3]. Previous clinical studies have suggested that statin treatment improves neurological function after acute stroke, especially atherothrombotic stroke [4-6]. In addition to lowering cholesterol level, statins might have neuroprotective function after ischemic stroke [7]. A recent meta-analysis study reported that statin use enhances collaterals and reperfusion and is associated with good functional outcome after acute stroke [8]. In animal studies, the neuroprotective effect of statins in ischemic stroke has been demonstrated [9, 10], and may be related to the promotion of brain plasticity through brain-derived neurotrophic factor (BDNF) [3, 10]. BDNF is a growth factor produced primarily in the brain but distributed in multiple organ systems [11]. In the nervous system, BDNF is very important in neuronal function and survival during development, and also plays an important role in neuroplasticity after brain injury [12, 13]. It has been reported that early administration of BDNF can reduce neuronal death and infarct volume after acute ischemic stroke [14, 15]. There is evidence supporting BDNF as index of neuroprotection [7]. Therefore, to study the neuroprotective effect of statins treatment, we set out to test the hypothesis that atorvastatin treatment is associated with serum BDNF levels and improved recovery of
3
neurological function after atherothrombotic stroke. It is known that BDNF readily crosses the blood brain barrier and serum BDNF levels represent the level of expression of BDNF in the brain [16]. Among different types of statins, atorvastatin is now considered as one of the most effective statins. Atorvastatin also has fewer side effects such as myopathy and
Downloaded by [NUS National University of Singapore] at 19:52 28 January 2016
hepatotoxicity compared to other statins [17]. Atorvastatin was selected in the present study since it easily crosses the blood-brain barrier and has been used in other clinical studies [16, 23]. It has been reported that intensive lipid intervention with high dosage statins reduces the incidence of stroke in a previous clinical study [18]. However, published studies have shown that high doses of atorvastatin elevate fasting blood glucose and HbA1C and significantly increase the risk of hemorrhagic stroke [19, 20]. In addition, Asians may have greater responses to statins compared to Caucasians due to genetic differences [21]. Therefore, we chose atorvastatin 20 mg per day as the treatment dosage in present study. Serum BDNF levels, National Institutes of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS), and Barthel Index (BI) were assessed in atorvastatin treatment group and placebo control group at 1 day and 6 weeks after acute ischemic stroke to examine the relationship between atorvastatin treatment, serum BDNF level, and functional recovery in patients with atherothrombotic stroke. Methods and material 1. Patients enrollment This is a prospective study of patients with acute ischemic stroke who presented to the Second Affiliated Hospital of Anhui Medical University from January 2014 to November 2014. This study was approved by the research ethics committee of AMU. All
4
patients signed the written informed consent before the study. Patients with acute ischemic stroke were admitted to the hospital and then screened for eligibility. Medical history and neurological examination were collected by the same neurologists at the hospital. Diagnosis was confirmed through computed tomography (CT) or magnetic resonance imaging (MRI). Echocardiography was performed to screen cardioembolism
Downloaded by [NUS National University of Singapore] at 19:52 28 January 2016
related stroke. CT angiography or magnetic resonance angiography were undergone to evaluate the extracranial artery and intracranial artery of the stroke patients. Then the ischemic stroke patients were further subdivided into five major etiologic subtypes: atherothrombosis, cardioembolism, small artery disease, stroke of other determined etiology and stroke of undetermined etiology based on the modified Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification [22]. The enrollment criteria for the study included: (a) age between 40 and 80 years old; (b) acute onset of stroke within 24 hours and beyond time window for tissue plasminogen activator (t-PA) treatment; (c) atherothrombotic subtype of stroke with homogeneous and cortical lesion; (d) and no previous statin use. The baseline demographic data and medical history of hypertension, hyperlipidemia, coronary artery disease and diabetes were recorded for all subjects in the study. 2. Assessment and follow up A total of 246 acute ischemic stroke patients were screened and 78 patients with acute atherothrombotic stroke were enrolled in the present study. The sample size was determined by a power analysis and the randomization is 1:1. All the enrolled patients were randomized to either the atorvastatin treatment group (n=39) or the placebo control group (n=39). The treatment group was given atorvastatin 20mg orally daily started one
5
day after stroke for 6 weeks, while the control group was given placebo once daily for 6 weeks. BDNF plays an important role in neurogenesis, synaptogenesis and axonal outgrowth which are established 4 to 6 weeks after acute stroke [14]. In the present study, we selected 1 day and 6 weeks after stroke to assess neurological function as well as serum BDNF level, which reflected before and after treatment timelines respectively. In
Downloaded by [NUS National University of Singapore] at 19:52 28 January 2016
addition, all subjects were treated with standard treatment for acute ischemic stroke (i.e. aspirin, intravenous fluid, permissive hypertension, etc.). Neurological function scores including the National Institutes of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS), and Barthel Index (BI) were assessed in atorvastatin treatment group and placebo control group at 1 day and 6 weeks after acute ischemic stroke by two neurologists who was blinded to the study allocation and laboratory measurement. All subjects were followed up for 6 weeks by the same neurologists. All peripheral blood samples were collected at day 1 and 6 weeks post stroke. The first blood sample was drawn within 24 hours after stroke onset. Serum was extracted after centrifugation at 3,000 rpm for 15 minutes and stored at -80°C immediately until assay. Serum BDNF levels were assayed by using enzyme linked immunosorbent assay (ELISA kit, Promega; Madison, WI, USA). The frozen serum samples were tested within one month after collection. All the samples were measured in duplicate and the averages were calculated for statistical analyses. The blood samples in atorvastatin group and control group were assayed by one technician who was blinded to the allocation and clinical data of the patients. 3. Statistical analyses
6
All analysis was performed using SPSS 16.0 for Windows (SPSS Inc., Chicago, IL, USA). Data were expressed as mean standard deviation (SD) or number of subjects (percentage). To compare the differences in clinical characteristics between treatment group and control group, chi-square test was used for categorized data and Student t test were used for continuous data which were normally distributed. Serum BDNF levels and
Downloaded by [NUS National University of Singapore] at 19:52 28 January 2016
neurological functional scores between different groups were analyzed by Mann-Whitney test as the data were not distributed normally. A value of p
ISSN: 0020-7454 (Print) 1543-5245 (Online) Journal homepage: http://www.tandfonline.com/loi/ines20
Atorvastatin treatment is associated with increased BDNF level and improved functional recovery after atherothrombotic stroke Jingmiao Zhang, Xiali Mu, Dane A Breker, Ying Li, Zongliang Gao & Yonglu Huang To cite this article: Jingmiao Zhang, Xiali Mu, Dane A Breker, Ying Li, Zongliang Gao & Yonglu Huang (2016): Atorvastatin treatment is associated with increased BDNF level and improved functional recovery after atherothrombotic stroke, International Journal of Neuroscience, DOI: 10.3109/00207454.2016.1146882 To link to this article: http://dx.doi.org/10.3109/00207454.2016.1146882
Accepted author version posted online: 27 Jan 2016.
Submit your article to this journal
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ines20 Download by: [NUS National University of Singapore]
Date: 28 January 2016, At: 19:52
Publisher: Taylor & Francis Journal: International Journal of Neuroscience DOI: http://dx.doi.org/10.3109/00207454.2016.1146882
Atorvastatin treatment is associated with increased BDNF level and improved functional recovery after atherothrombotic stroke Jingmiao Zhang1, Xiali Mu1, Dane A Breker2, Ying Li1, Zongliang Gao1, Yonglu Huang1,* Downloaded by [NUS National University of Singapore] at 19:52 28 January 2016
1
The Second Affiliated Hospital of Anhui Medical University, Department of Neurology,
Hefei, Anhui 230601, P. R. China, 2
University of Michigan, Department of Neurology, Ann Arbor, Michigan 48109, USA
*Correspondence to: Yonglu Huang, MD/PhD, Department of Neurology, The Second Affiliated Hospital of Anhui Medical University, 678 Furong Road, Hefei 230601, P. R. China; Tel.: 86-551-6386-9586; Fax: 86-551-6386-9400; Email: [email protected]
Abstract Back ground: Statins have a positive impact on ischemic stroke outcome. It has been reported that Statin have neuroprotective function after ischemic stroke in addition to lipid-lowering effect in animal model. However, the neuroprotective function of statin after stroke has not been confirmed in clinical studies. The aim of present study was to evaluate in a clinical model if statins induce neuroprotection after stroke. We therefore assessed serum BDNF levels and functional recovery in atherothrombotic stroke patients and investigated their relationship with atorvastatin treatment. Methods: 78 patients with atherothrombotic stroke were enrolled and randomly assigned to atorvastatin treatment
1
group or placebo control group. Neurological function after stroke was assessed with the National Institutes of Health Stroke Scale (NIHSS), Modified Rankin Scale (mRS) and Barthel Index (BI). Serum BDNF levels were both measured at 1 day and 6 weeks after stroke. Linear regression was used to assess the association between BDNF levels and neurological function scores. Results: The mRS and BI were markedly improved in the
Downloaded by [NUS National University of Singapore] at 19:52 28 January 2016
atorvastatin group when compared to placebo at 6 weeks after stroke. The serum BDNF levels in atorvastatin group were significantly elevated by 6 weeks after stroke and higher than the BDNF levels in controls. In addition, the serum BDNF levels significantly correlated with mRS and BI after stroke. Our results demonstrated that atorvastatin treatment was associated with increased BDNF level and improved functional recovery after atherothrombotic stroke. Conclusion: This study indicates that atorvastatin-related elevation in BDNF level may promote functional recovery in stroke patients. Keywords: Stroke, BDNF, atorvastatin, NIHSS, mRS, BI
2
Introduction Stroke has a high incidence of morbidity and mortality and leads to substantial burden for society and patients’ families. Recent studies have shown that stroke recurrence may be reduced by statins [1]. Statins are a class of HMG-CoA (3hydroxy-3-methyl-Glutaryl-coenzyme A) reductase inhibitors that prevent cholesterol
Downloaded by [NUS National University of Singapore] at 19:52 28 January 2016
synthesis. It has also been reported that statins have a positive impact on acute ischemic stroke outcome in addition to the lipid lowering effects [2,3]. Previous clinical studies have suggested that statin treatment improves neurological function after acute stroke, especially atherothrombotic stroke [4-6]. In addition to lowering cholesterol level, statins might have neuroprotective function after ischemic stroke [7]. A recent meta-analysis study reported that statin use enhances collaterals and reperfusion and is associated with good functional outcome after acute stroke [8]. In animal studies, the neuroprotective effect of statins in ischemic stroke has been demonstrated [9, 10], and may be related to the promotion of brain plasticity through brain-derived neurotrophic factor (BDNF) [3, 10]. BDNF is a growth factor produced primarily in the brain but distributed in multiple organ systems [11]. In the nervous system, BDNF is very important in neuronal function and survival during development, and also plays an important role in neuroplasticity after brain injury [12, 13]. It has been reported that early administration of BDNF can reduce neuronal death and infarct volume after acute ischemic stroke [14, 15]. There is evidence supporting BDNF as index of neuroprotection [7]. Therefore, to study the neuroprotective effect of statins treatment, we set out to test the hypothesis that atorvastatin treatment is associated with serum BDNF levels and improved recovery of
3
neurological function after atherothrombotic stroke. It is known that BDNF readily crosses the blood brain barrier and serum BDNF levels represent the level of expression of BDNF in the brain [16]. Among different types of statins, atorvastatin is now considered as one of the most effective statins. Atorvastatin also has fewer side effects such as myopathy and
Downloaded by [NUS National University of Singapore] at 19:52 28 January 2016
hepatotoxicity compared to other statins [17]. Atorvastatin was selected in the present study since it easily crosses the blood-brain barrier and has been used in other clinical studies [16, 23]. It has been reported that intensive lipid intervention with high dosage statins reduces the incidence of stroke in a previous clinical study [18]. However, published studies have shown that high doses of atorvastatin elevate fasting blood glucose and HbA1C and significantly increase the risk of hemorrhagic stroke [19, 20]. In addition, Asians may have greater responses to statins compared to Caucasians due to genetic differences [21]. Therefore, we chose atorvastatin 20 mg per day as the treatment dosage in present study. Serum BDNF levels, National Institutes of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS), and Barthel Index (BI) were assessed in atorvastatin treatment group and placebo control group at 1 day and 6 weeks after acute ischemic stroke to examine the relationship between atorvastatin treatment, serum BDNF level, and functional recovery in patients with atherothrombotic stroke. Methods and material 1. Patients enrollment This is a prospective study of patients with acute ischemic stroke who presented to the Second Affiliated Hospital of Anhui Medical University from January 2014 to November 2014. This study was approved by the research ethics committee of AMU. All
4
patients signed the written informed consent before the study. Patients with acute ischemic stroke were admitted to the hospital and then screened for eligibility. Medical history and neurological examination were collected by the same neurologists at the hospital. Diagnosis was confirmed through computed tomography (CT) or magnetic resonance imaging (MRI). Echocardiography was performed to screen cardioembolism
Downloaded by [NUS National University of Singapore] at 19:52 28 January 2016
related stroke. CT angiography or magnetic resonance angiography were undergone to evaluate the extracranial artery and intracranial artery of the stroke patients. Then the ischemic stroke patients were further subdivided into five major etiologic subtypes: atherothrombosis, cardioembolism, small artery disease, stroke of other determined etiology and stroke of undetermined etiology based on the modified Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification [22]. The enrollment criteria for the study included: (a) age between 40 and 80 years old; (b) acute onset of stroke within 24 hours and beyond time window for tissue plasminogen activator (t-PA) treatment; (c) atherothrombotic subtype of stroke with homogeneous and cortical lesion; (d) and no previous statin use. The baseline demographic data and medical history of hypertension, hyperlipidemia, coronary artery disease and diabetes were recorded for all subjects in the study. 2. Assessment and follow up A total of 246 acute ischemic stroke patients were screened and 78 patients with acute atherothrombotic stroke were enrolled in the present study. The sample size was determined by a power analysis and the randomization is 1:1. All the enrolled patients were randomized to either the atorvastatin treatment group (n=39) or the placebo control group (n=39). The treatment group was given atorvastatin 20mg orally daily started one
5
day after stroke for 6 weeks, while the control group was given placebo once daily for 6 weeks. BDNF plays an important role in neurogenesis, synaptogenesis and axonal outgrowth which are established 4 to 6 weeks after acute stroke [14]. In the present study, we selected 1 day and 6 weeks after stroke to assess neurological function as well as serum BDNF level, which reflected before and after treatment timelines respectively. In
Downloaded by [NUS National University of Singapore] at 19:52 28 January 2016
addition, all subjects were treated with standard treatment for acute ischemic stroke (i.e. aspirin, intravenous fluid, permissive hypertension, etc.). Neurological function scores including the National Institutes of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS), and Barthel Index (BI) were assessed in atorvastatin treatment group and placebo control group at 1 day and 6 weeks after acute ischemic stroke by two neurologists who was blinded to the study allocation and laboratory measurement. All subjects were followed up for 6 weeks by the same neurologists. All peripheral blood samples were collected at day 1 and 6 weeks post stroke. The first blood sample was drawn within 24 hours after stroke onset. Serum was extracted after centrifugation at 3,000 rpm for 15 minutes and stored at -80°C immediately until assay. Serum BDNF levels were assayed by using enzyme linked immunosorbent assay (ELISA kit, Promega; Madison, WI, USA). The frozen serum samples were tested within one month after collection. All the samples were measured in duplicate and the averages were calculated for statistical analyses. The blood samples in atorvastatin group and control group were assayed by one technician who was blinded to the allocation and clinical data of the patients. 3. Statistical analyses
6
All analysis was performed using SPSS 16.0 for Windows (SPSS Inc., Chicago, IL, USA). Data were expressed as mean standard deviation (SD) or number of subjects (percentage). To compare the differences in clinical characteristics between treatment group and control group, chi-square test was used for categorized data and Student t test were used for continuous data which were normally distributed. Serum BDNF levels and
Downloaded by [NUS National University of Singapore] at 19:52 28 January 2016
neurological functional scores between different groups were analyzed by Mann-Whitney test as the data were not distributed normally. A value of p
