A double blind placebo RCT to investigate the effects of serotonergic modulation on brain excitability and motor recovery in stroke patients

[Drugs for improvement of motor deficits after stroke]

Randomized controlled trials with a variety of drugs have been performed for approximately 20 years in order to support functional restitution of motor deficits after a stroke. Nowadays, serotonin reuptake inhibitors show the highest level of evidence due to the largest number of positive studies and L‑dopa also seems to be effective; however, much fewer studies have been conducted. In the majority of trials amphetamines provided no additional benefits and D‑cycloserine cannot be recommended either. Future therapeutic approaches, e.g. anti-nogo antibodies and cell therapy are presented.

Rehabilitation of Motor Function after Stroke: A Multiple Systematic Review Focused on Techniques to Stimulate Upper Extremity Recovery

Stroke is one of the leading causes for disability worldwide. Motor function deficits due to stroke affect the patients' mobility, their limitation in daily life activities, their participation in society and their odds of returning to professional activities. All of these factors contribute to a low overall quality of life. Rehabilitation training is the most effective way to reduce motor impairments in stroke patients. This multiple systematic review focuses both on standard treatment methods and on innovating rehabilitation techniques used to promote upper extremity motor function in stroke patients. A total number of 5712 publications on stroke rehabilitation was systematically reviewed for relevance and quality with regards to upper extremity motor outcome. This procedure yielded 270 publications corresponding to the inclusion criteria of the systematic review. Recent technology-based interventions in stroke rehabilitation including non-invasive brain stimulation, robot-assisted training, and virtual reality immersion are addressed. Finally, a decisional tree based on evidence from the literature and characteristics of stroke patients is proposed. At present, the stroke rehabilitation field faces the challenge to tailor evidence-based treatment strategies to the needs of the individual stroke patient. Interventions can be combined in order to achieve the maximal motor function recovery for each patient. Though the efficacy of some interventions may be under debate, motor skill learning, and some new technological approaches give promising outcome prognosis in stroke motor rehabilitation.

Chronic Enhancement of Serotonin Facilitates Excitatory Transcranial Direct Current Stimulation-Induced Neuroplasticity

Serotonin affects memory formation via modulating long-term potentiation (LTP) and depression (LTD). Accordingly, acute selective serotonin reuptake inhibitor (SSRI) administration enhanced LTP-like plasticity induced by transcranial direct current stimulation (tDCS) in humans. However, it usually takes some time for SSRI to reduce clinical symptoms such as anxiety, negative mood, and related symptoms of depression and anxiety disorders. This might be related to an at least partially different effect of chronic serotonergic enhancement on plasticity, as compared with single-dose medication. Here we explored the impact of chronic application of the SSRI citalopram (CIT) on plasticity induced by tDCS in healthy humans in a partially double-blinded, placebo (PLC)-controlled, randomized crossover study. Furthermore, we explored the dependency of plasticity induction from the glutamatergic system via N-methyl-D-aspartate receptor antagonism. Twelve healthy subjects received PLC medication, combined with anodal or cathodal tDCS of the primary motor cortex. Afterwards, the same subjects took CIT (20 mg/day) consecutively for 35 days. During this period, four additional interventions were performed (CIT and PLC medication with anodal/cathodal tDCS, CIT and dextromethorphan (150 mg) with anodal/cathodal tDCS). Plasticity was monitored by motor-evoked potential amplitudes elicited by transcranial magnetic stimulation. Chronic application of CIT increased and prolonged the LTP-like plasticity induced by anodal tDCS for over 24 h, and converted cathodal tDCS-induced LTD-like plasticity into facilitation. These effects were abolished by dextromethorphan. Chronic serotonergic enhancement results in a strengthening of LTP-like glutamatergic plasticity, which might partially explain the therapeutic impact of SSRIs in depression and other neuropsychiatric diseases.

Fluoxetine Maintains a State of Heightened Responsiveness to Motor Training Early After Stroke in a Mouse Model

BACKGROUND AND PURPOSE

Data from both humans and animal models suggest that most recovery from motor impairment after stroke occurs in a sensitive period that lasts only weeks and is mediated, in part, by an increased responsiveness to training. Here, we used a mouse model of focal cortical stroke to test 2 hypotheses. First, we investigated whether responsiveness to training decreases over time after stroke. Second, we tested whether fluoxetine, which can influence synaptic plasticity and stroke recovery, can prolong the period over which large training-related gains can be elicited after stroke.

METHODS

Mice were trained to perform a skilled prehension task to an asymptotic level of performance after which they underwent stroke induction in the caudal forelimb area. The mice were then retrained after a 1- or 7-day delay with and without fluoxetine.

RESULTS

Recovery of prehension after a caudal forelimb area stroke was complete if training was initiated 1 day after stroke but incomplete if it was delayed by 7 days. In contrast, if fluoxetine was administered at 24 hours after stroke, then complete recovery of prehension was observed even with the 7-day training delay. Fluoxetine seemed to mediate its beneficial effect by reducing inhibitory interneuron expression in intact premotor cortex rather than through effects on infarct volume or cell death.

CONCLUSIONS

There is a gradient of diminishing responsiveness to motor training over the first week after stroke. Fluoxetine can overcome this gradient and maintain maximal levels of responsiveness to training even 7 days after stroke.

Selective serotonin reuptake inhibitors to improve outcome in acute ischemic stroke: possible mechanisms and clinical evidence

BACKGROUND

Several clinical studies have indicated that selective serotonin reuptake inhibitors (SSRIs) administered in patients after acute ischemic stroke can improve clinical recovery independently of depression. Due to small sample sizes and heterogeneous study designs interpretability was limited in these studies. The mechanisms of action whereby SSRI might improve recovery from acute ischemic stroke are not fully elucidated.

METHODS

We searched MEDLINE using the PubMed interface to identify evidence of SSRI mediated improvement of recovery from acute ischemic stroke and reviewed the literature on the potential underlying mechanisms of action.

RESULTS

Among identified clinical studies, a well-designed randomized, double-blind, and placebo-controlled study (FLAME - fluoxetine for motor recovery after acute ischemic stroke) demonstrated improved recovery of motor function in stroke patients receiving fluoxetine. The positive effects of SSRIs on stroke recovery were further supported by a meta-analysis of 52 trials in a total of 4060 participants published by the Cochrane collaboration. Based on animal models, the mechanisms whereby SSRIs might ameliorate functional and structural ischemic-brain damage were suggested to include stimulation of neurogenesis with migration of newly generated cells toward ischemic-brain regions, anti-inflammatory neuroprotection, improved regulation of cerebral blood flow, and modulation of the adrenergic neurohormonal system. However, to date, it remains speculative if and to what degree these mechanisms convert into humans and randomized controlled trials in large populations of stroke patients comparing different SSRIs are still lacking.

CONCLUSION

In addition to the need of comprehensive-clinical evidence, further elucidation of the beneficial mechanisms whereby SSRIs may improve structural and functional recovery from ischemic-brain damage is needed to form a basis for translation into clinical practice.

The FOCUS, AFFINITY and EFFECTS trials studying the effect(s) of fluoxetine in patients with a recent stroke: a study protocol for three multicentre randomised controlled trials

Background

Several small trials have suggested that fluoxetine improves neurological recovery from stroke. FOCUS, AFFINITY and EFFECTS are a family of investigator-led, multicentre, parallel group, randomised, placebo-controlled trials that aim to determine whether routine administration of fluoxetine (20 mg daily) for 6 months after acute stroke improves patients’ functional outcome.

Methods/Design

The three trial investigator teams have collaboratively developed a core protocol. Minor variations have been tailored to the national setting in the UK (FOCUS), Australia and New Zealand (AFFINITY) and Sweden (EFFECTS). Each trial is run and funded independently and will report its own results. A prospectively planned individual patient data meta-analysis of all three trials will subsequently provide the most precise estimate of the overall effect of fluoxetine after stroke and establish whether any effects differ between trials and subgroups of patients.

The trials include patients ≥18 years old with a clinical diagnosis of stroke, persisting focal neurological deficits at randomisation between 2 and 15 days after stroke onset. Patients are randomised centrally via web-based randomisation systems using a common minimisation algorithm. Patients are allocated fluoxetine 20 mg once daily or matching placebo capsules for 6 months. Our primary outcome measure is the modified Rankin scale (mRS) at 6 months. Secondary outcomes include the Stroke Impact Scale, EuroQol (EQ5D-5 L), the vitality subscale of the Short-Form 36, diagnosis of depression, adherence to medication, adverse events and resource use. Outcomes are collected at 6 and 12 months. The methods of collecting these data are tailored to the national setting. If FOCUS, AFFINITY and EFFECTS combined enrol 6000 participants as planned, they would have 90 % power (alpha 5 %) to detect a common odds ratio of 1.16, equivalent to a 3.7 % absolute difference in percentage with mRS 0–2 (44.0 % to 47.7 %). This is based on an ordinal analysis of mRS adjusted for baseline variables included in the minimisation algorithm.

Discussion

If fluoxetine is safe and effective in promoting functional recovery, it could be rapidly, widely and affordably implemented in routine clinical practice and reduce the burden of disability due to stroke.

Trial registration

FOCUS: ISRCTN83290762 (23/05/2012), AFFINITY: ACTRN12611000774921 (22/07/2011). EFFECTS: ISRCTN13020412 (19/12/2014).

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-015-0864-1) contains supplementary material, which is available to authorized users.

The Effects of Pretreatment versus De Novo Treatment with Selective Serotonin Reuptake Inhibitors on Short-term Outcome after Acute Ischemic Stroke

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs) administered in patients following acute ischemic stroke have shown to improve clinical recovery independently of changes in depression. Animal studies have demonstrated that sustained SSRI treatment is superior to short-term SSRI in evoking neurogenesis but how this benefit translates into humans remains to be answered. We hypothesized that in acute ischemic stroke patients, SSRI treatment started before the event leads to improved short-term outcomes compared to de novo SSRI treatment poststroke.

METHODS

We performed an exploratory analysis in consecutive acute ischemic stroke patients and compared patients already receiving fluoxetine, citalopram, or escitalopram with those who started treatment de novo.

RESULTS

Of 2653 screened patients, 239 were included (age, 69 ± 14 years; 42% men, baseline median National Institutes of Health Stroke Scale score, 7 [IQR, 10]). Of these patients, 51 started treatment with SSRI before stroke and 188 were prescribed newly SSRIs during hospitalization. In the adjusted multivariate logistic regression models, SSRI pretreatment was associated with favorable functional outcome at discharge defined as a modified Rankin Scale score of 2 or less (odds ratio [OR], 4.00; 95% confidence interval [CI], 1.68-9.57; P < .005), improved early clinical recovery (OR, 2.35; 95% CI, 1.15-4.81; P = .02), and a trend toward prediction of superior motor recovery (OR, 1.82; 95% CI, .90-3.68; P < .01).

CONCLUSIONS

Our data suggest that SSRI pretreatment may improve clinical outcomes in the early stages of acute ischemic stroke supporting the hypothesis that prolonged SSRI treatment started prestroke is superior to poststroke SSRI.

Emerging treatments for motor rehabilitation after stroke

Although numerous treatments are available to improve cerebral perfusion after acute stroke and prevent recurrent stroke, few rehabilitation treatments have been conclusively shown to improve neurologic recovery. The majority of stroke survivors with motor impairment do not recover to their functional baseline, and there remains a need for novel neurorehabilitation treatments to minimize long-term disability, maximize quality of life, and optimize psychosocial outcomes. In recent years, several novel therapies have emerged to restore motor function after stroke, and additional investigational treatments have also shown promise. Here, we familiarize the neurohospitalist with emerging treatments for poststroke motor rehabilitation. The rehabilitation treatments covered in this review will include selective serotonin reuptake inhibitor medications, constraint-induced movement therapy, noninvasive brain stimulation, mirror therapy, and motor imagery or mental practice.

Efficacy of antidepressants in animal models of ischemic stroke: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

Poststroke depression is a prevalent complication of stroke with unclear pathogenesis. The benefits of antidepressants in this context and their effects on stroke recovery other than effects on mood are not clearly defined, with some studies suggesting efficacy in improving functional outcome in both depressed and nondepressed stroke patients. We have analyzed the preclinical animal data on antidepressant treatment in focal cerebral ischemia, modeled±depression, to help inform clinical trial design.

METHODS

We performed a systematic review and meta-analysis of data from experiments testing the efficacy of antidepressants versus no treatment to reduce infarct volume or improve neurobehavioral or neurogenesis outcomes in animal models of stroke. We used random-effects metaregression to test the impact of study quality and design characteristics and used trim and fill to assess publication bias.

RESULTS

We identified 44 publications describing the effects of 22 antidepressant drugs. The median quality checklist score was 5 of a possible 10 (interquartile range, 4-7). Overall, antidepressants reduced infarct volume by 27.3% (95% confidence interval, 20.7%-33.8%) and improved neurobehavioral outcomes by 53.7% (46.4%-61.1%). There was little evidence for an effect of selective serotonin reuptake inhibitors on infarct volume. For neurobehavioral outcomes there was evidence of publication bias. Selective serotonin reuptake inhibitors were the most frequently studied antidepressant subtype and improved neurobehavioral outcome by 51.8% (38.6%-64.9%) and increased neurogenesis by 2.2 SD (1.3-3.0).

CONCLUSIONS

In line with current clinical data and despite some limitations, antidepressant treatments seem to improve infarct volume and neurobehavioral outcome in animal models of ischemic stroke.

Vascular cognitive impairment and post-stroke cognitive deficits

Vascular cognitive impairment (VCI) and focal post-stroke cognitive deficits are an unfortunately common occurrence. Despite this, our understanding of risk factors for development of VCI and treatment thereof is embarrassingly limited. While no FDA approved treatments exist for VCI, recent and ongoing research sheds some light on the problem, showing some efficacy of cholinesterase inhibitors and antidepressants, treatment of vascular risk factors, and other investigational drugs. Treatments for focal cognitive impairments such as aphasia and neglect are also limited, primarily by the size of studies that have been done. With the more widespread acceptance of the AHA-ASA diagnostic criteria for VCI and its subtypes, perhaps we will start to see more in the way of compelling treatment trials.

Pharmacological therapies to enhance motor recovery and walking after stroke: emerging strategies

Stroke is the most common serious neurological disorder. To date, the focus for research and trials has been on prevention and acute care. Many patients are left with serious neurological impairments and limitations in activity and participation after stroke. Recent preliminary research and trials suggest that the brain is 'plastic' and that the natural history of stroke recovery can be improved by physical therapy and pharmacotherapy. Motor weakness and the ability to walk have been the primary targets for testing interventions that may improve recovery after stroke. Physical therapeutic interventions enhance recovery after stroke; however, the timing, duration and type of intervention require clarification and further trials. Pharmacotherapy, in particular with dopaminergic and selective serotonin-reuptake inhibitors, shows promise in enhancing motor recovery after stroke; however, further large-scale trials are required.

Stroke Recovery: Surprising Influences and Residual Consequences

There is startling individual variability in the degree to which people recover from stroke, and the duration of time over which recovery of some symptoms occur. There are a variety of mechanisms of recovery from stroke, which take place at distinct time points after stroke and are influenced by different variables. We review recent studies from our laboratory that unveil some surprising findings, such as the role of education in chronic recovery. We also report data showing that the consequences that most plague survivors of stroke and their caregivers are not dependence in activities of daily living, but loss of more high level functions, such as empathy or written language. These results have implications for rehabilitation and management of stroke.

Pharmacologic approaches to cerebral aging and neuroplasticity: insights from the stroke model

Brain plasticity is an intrinsic characteristic of the nervous system that allows continuous remodeling of brain functions in pathophysiological conditions. Although normal aging is associated with morphological modifications and decline of cerebral functions, brain plasticity is at least partially preserved in elderly individuals. A growing body of evidence supports the notion that cognitive enrichment and aerobic training induce a dynamic reorganization of higher cerebral functions, thereby helping to maintain operational skills in the elderly and reducing the incidence of dementia. The stroke model clearly shows that spontaneous brain plasticity exists after a lesion, even in old patients, and that it can be modulated through external factors like rehabilitation and drugs. Whether drugs can be used with the aim of modulating the effects of physical training or cognitive stimulation in healthy aged people has not been addressed until now. The risk:benefit ratio will be the key question with regard to the ethical aspect of this challenge. We review in this article the main aspects of human brain plasticity as shown in patients with stroke, the drug modulation of brain plasticity and its consequences on recovery, and finally we address the question of the influence of aging on brain plasticity.

The role of citicoline in neuroprotection and neurorepair in ischemic stroke

Advances in acute stroke therapy resulting from thrombolytic treatment, endovascular procedures, and stroke units have improved significantly stroke survival and prognosis; however, for the large majority of patients lacking access to advanced therapies stroke mortality and residual morbidity remain high and many patients become incapacitated by motor and cognitive deficits, with loss of independence in activities of daily living. Therefore, over the past several years, research has been directed to limit the brain lesions produced by acute ischemia (neuroprotection) and to increase the recovery, plasticity and neuroregenerative processes that complement rehabilitation and enhance the possibility of recovery and return to normal functions (neurorepair). Citicoline has therapeutic effects at several stages of the ischemic cascade in acute ischemic stroke and has demonstrated efficiency in a multiplicity of animal models of acute stroke. Long-term treatment with citicoline is safe and effective, improving post-stroke cognitive decline and enhancing patients' functional recovery. Prolonged citicoline administration at optimal doses has been demonstrated to be remarkably well tolerated and to enhance endogenous mechanisms of neurogenesis and neurorepair contributing to physical therapy and rehabilitation.

Post-stroke depression and the aging brain

Ageing is associated with changes in the function of various organ systems. Changes in the cardiovascular system affect both directly and indirectly the function in a variety of organs, including the brain, with consequent neurological (motor and sensory performance) and cognitive impairments, as well as leading to the development of various psychiatric diseases. Post-stroke depression (PSD) is among the most frequent neuropsychiatric consequences of cerebral ischemia. This review discusses several animal models used for the study of PSD and summarizes recent findings in the genomic profile of the ageing brain, which are associated with age-related disorders in the elderly. Since stroke and depression are diseases with increased incidence in the elderly, great clinical benefit may especially accrue from deciphering and targeting basic mechanisms underlying PSD. Finally, we discuss the relationship between ageing, circadian rhythmicity and PSD.

Use of antidepressant medications to improve outcomes after stroke

Interest in the use of antidepressants after stroke has been renewed by better knowledge of poststroke depression, but mainly by the capacity of some of them to promote functional recovery of nondepressed subjects. Recombinant tissue plasminogen activator thrombolysis within the first few hours after the stroke is currently the only validated treatment able to improve the spontaneous--and most of the time incomplete--recovery of neurological functions after stroke. However, we have learned from research over the last decade, in part based on the considerable improvement of neuroimaging techniques, that spontaneous recovery of neurological functions is associated with a large intracerebral reorganization of the damaged human brain. The question of whether lesioned-brain plasticity can be modulated by external factors such as pharmacological antidepressant agents is now being addressed with the aim of improving recovery and reducing the final disability of patients. Poststroke depression is known to be frequent and deleterious for patient outcome. We review the interest in the use of antidepressants after stroke in classic but often neglected poststroke depression and we strongly underline the action of some antidepressants in promoting functional recovery of nondepressed patients after stroke.

Citalopram enhances neurovascular regeneration and sensorimotor functional recovery after ischemic stroke in mice

Recent clinical trials have demonstrated that treatment with selective serotonin reuptake inhibitors after stroke enhances motor functional recovery; however, the underlying mechanisms remain to be further elucidated. We hypothesized that daily administration of the clinical drug citalopram would produce these functional benefits via enhancing neurovascular repair in the ischemic peri-infarct region. To test this hypothesis, focal ischemic stroke was induced in male C57/B6 mice by permanent ligation of distal branches of the middle cerebral artery to the barrel cortex and 7-min occlusion of the bilateral common carotid arteries. Citalopram (10mg/kg, i.p.) was injected 24h after stroke and daily thereafter. To label proliferating cells, bromo-deoxyuridine was injected daily beginning 3 days after stroke. Immunohistochemical and functional assays were performed to elucidate citalopram-mediated cellular and sensorimotor changes after stroke. Citalopram treatment had no significant effect on infarct formation or edema 3 days after stroke; however, citalopram-treated mice had better functional recovery than saline-treated controls 3 and 14 days after stroke in the adhesive removal test. Increased expression of brain-derived neurotrophic factor was detected in the peri-infarct region 7 days after stroke in citalopram-treated animals. The number of proliferating neural progenitor cells and the distance of neuroblast migration from the sub-ventricular zone toward the ischemic cortex were significantly greater in citalopram-treated mice at 7 days after stroke. Immunohistochemical staining and co-localization analysis showed that citalopram-treated animals generated more new neurons and microvessels in the peri-infarct region 21 and 28 days after stroke. Taken together, these results suggest that citalopram promotes post-stroke sensorimotor recovery likely via enhancing neurogenesis, neural cell migration and the microvessel support in the peri-infarct region of the ischemic brain.

Fluoxetine for motor recovery after acute intracerebral hemorrhage (FMRICH): study protocol for a randomized, double-blind, placebo-controlled, multicenter trial

Background

Spontaneous, nontraumatic intracerebral hemorrhage (ICH) is a subtype of stroke that causes a great amount of disability and economic and social burden. This is particularly true in developing countries where it accounts for between 20% and 50% of all strokes. Pharmacological and surgical interventions have been attempted to reduce the mortality and disability caused by ICH, with unsuccessful results. Recently, the use of fluoxetine in addition to physical rehabilitation has been proven useful to improve motor recovery following cerebral infarct. The purpose of this study is to test whether a 3-month treatment with fluoxetine enhances motor recovery in nondepressed patients with acute intracerebral hemorrhage.

Methods/design

Our study is a randomized, double-blind, placebo-controlled, multicenter clinical trial. We will recruit 86 patients with intracerebral hemorrhage of both sexes, aged >18 years, from four Mexican hospitals. The patients will receive either 20 mg of fluoxetine or a placebo once daily for 90 days. The primary outcome is the mean change in the Fugl-Meyer Motor Scale score between inclusion (day 0) and day 90. The secondary outcomes will be changes in the Barthel Index, the Modified Rankin scale and the National Institutes of Health stroke scale. The outcomes will be measured at day 42 ± 7days and at day 90, for a total of four visits with each subject (at screening and at 0, 42 and 90 days).

Discussion

Current guidelines recommend early supported hospital discharge and home-based rehabilitation programs as the only cost-effective intervention to aid the recovery of patients with intracerebral hemorrhage. Nevertheless, such interventions are dependent on available resources and funding, which make them very difficult to implement in developing countries. We believe that the identification of a helpful pharmacological intervention to aid the motor recovery of these patients will constitute a breakthrough that will have a major impact in reducing the burden of disease caused by this subtype of stroke worldwide, especially in the developing world.

Trial registration

Current Controlled Trials NCT01737541

Post-stroke depression: mechanisms, translation and therapy

The interaction between depression and stroke is highly complex. Post-stroke depression (PSD) is among the most frequent neuropsychiatric consequences of stroke. Depression also negatively impacts stroke outcome with increased morbidity, mortality and poorer functional recovery. Antidepressants such as the commonly prescribed selective serotonin reuptake inhibitors improve stroke outcome, an effect that may extend far beyond depression, e.g., to motor recovery. The main biological theory of PSD is the amine hypothesis. Conceivably, ischaemic lesions interrupt the projections ascending from midbrain and brainstem, leading to a decreased bioavailability of the biogenic amines – serotonin (5HT), dopamine (DA) and norepinephrine (NE). Acetylcholine would also be involved. So far, preclinical and translational research on PSD is largely lacking. The implementation and characterization of suitable animal models is clearly a major prerequisite for deeper insights into the biological basis of post-stroke mood disturbances. Equally importantly, experimental models may also pave the way for the discovery of novel therapeutic targets. If we cannot prevent stroke, we shall try to limit its long-term consequences. This review therefore presents animal models of PSD and summarizes potential underlying mechanisms including genomic signatures, neurotransmitter and neurotrophin signalling, hippocampal neurogenesis, cellular plasticity in the ischaemic lesion, secondary degenerative changes, activation of the hypothalamo-pituitary-adrenal (HPA) axis and neuroinflammation. As stroke is a disease of the elderly, great clinical benefit may especially accrue from deciphering and targeting basic mechanisms underlying PSD in aged animals.

Treatment of neurodevelopmental disorders in adulthood

Brain development in neurodevelopmental disorders has been considered to comprise a sequence of critical periods, and abnormalities occurring during early development have been considered irreversible in adulthood. However, findings in mouse models of neurodevelopmental disorders, including fragile X, Rett syndrome, Down syndrome, and neurofibromatosis type I suggest that it is possible to reverse certain molecular, electrophysiological, and behavioral deficits associated with these disorders in adults by genetic or pharmacological manipulations. Furthermore, recent studies have suggested that critical period-like plasticity can be reactivated in the adult brain by environmental manipulations or by pharmacotherapy. These studies open up a tantalizing possibility that targeted pharmacological treatments in combination with regimes of training or rehabilitation might alleviate or reverse the symptoms of neurodevelopmental disorders even after the end of critical developmental periods. Even though translation from animal experimentation to clinical practice is challenging, these results suggest a rational basis for treatment of neurodevelopmental disorders in adulthood.

Selective serotonin reuptake inhibitors (SSRIs) for stroke recovery

BACKGROUND

Stroke is the major cause of adult disability. Selective serotonin reuptake inhibitors (SSRIs) have been used for many years to manage depression. Recently, small trials have demonstrated that SSRIs might improve recovery after stroke, even in people who are not depressed. Systematic reviews and meta-analyses are the least biased way to bring together data from several trials. Given the promising effect of SSRIs on stroke recovery seen in small trials, a systematic review and meta-analysis is needed.

OBJECTIVES

To determine whether SSRIs improve recovery after stroke, and whether treatment with SSRIs was associated with adverse effects.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (August 2011), Cochrane Depression Anxiety and Neurosis Group Trials Register (November 2011), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 8), MEDLINE (from 1948 to August 2011), EMBASE (from 1980 to August 2011), CINAHL (from 1982 to August 2011), AMED (Allied and Complementary Medicine) (from 1985 to August 2011), PsycINFO (from 1967 to August 2011) and PsycBITE (Pyschological Database for Brain Impairment Treatment Efficacy) (March 2012). To identify further published, unpublished and ongoing trials we searched trials registers, pharmaceutical websites, reference lists, contacted experts and performed citation tracking of included studies.

SELECTION CRITERIA

We included randomised controlled trials that recruited stroke survivors (ischaemic or haemorrhagic) at any time within the first year. The intervention was any SSRI, given at any dose, for any period. We excluded drugs with mixed pharmacological effects. The comparator was usual care or placebo. In order to be included, trials had to collect data on at least one of our primary (dependence and disability) or secondary (impairments, depression, anxiety, quality of life, fatigue, healthcare cost, death, adverse events and leaving the trial early) outcomes.

DATA COLLECTION AND ANALYSIS

We extracted data on demographics, type of stroke, time since stroke, our primary and secondary outcomes, and sources of bias. For trials in English, two review authors independently extracted data. For Chinese papers, one review author extracted data. We used standardised mean differences (SMD) to estimate treatment effects for continuous variables, and risk ratios (RR) for dichotomous effects, with their 95% confidence intervals (CIs).

MAIN RESULTS

We identified 56 completed trials of SSRI versus control, of which 52 trials (4059 participants) provided data for meta-analysis. There were statistically significant benefits of SSRI on both of the primary outcomes: RR for reducing dependency at the end of treatment was 0.81 (95% CI 0.68 to 0.97) based on one trial, and for disability score, the SMD was 0.91 (95% CI 0.60 to 1.22) (22 trials involving 1343 participants) with high heterogeneity between trials (I(2) = 87%; P < 0.0001). For neurological deficit, depression and anxiety, there were statistically significant benefits of SSRIs. For neurological deficit score, the SMD was -1.00 (95% CI -1.26 to -0.75) (29 trials involving 2011 participants) with high heterogeneity between trials (I(2) = 86%; P < 0.00001). For dichotomous depression scores, the RR was 0.43 (95% CI 0.24 to 0.77) (eight trials involving 771 participants) with high heterogeneity between trials (I(2) = 77%; P < 0.0001). For continuous depression scores, the SMD was -1.91 (95% CI -2.34 to -1.48) (39 trials involving 2728 participants) with high heterogeneity between trials (I(2) = 95%; P < 0.00001). For anxiety, the SMD was -0.77 (95% CI -1.52 to -0.02) (eight trials involving 413 participants) with high heterogeneity between trials (I(2) = 92%; P < 0.00001). There was no statistically significant benefit of SSRI on cognition, death, motor deficits and leaving the trial early. For cognition, the SMD was 0.32 (95% CI -0.23 to 0.86), (seven trials involving 425 participants) with high heterogeneity between trials (I(2) = 86%; P < 0.00001). The RR for death was 0.76 (95% CI 0.34 to 1.70) (46 trials involving 3344 participants) with no heterogeneity between trials (I(2) = 0%; P = 0.85). For motor deficits, the SMD was -0.33 (95% CI -1.22 to 0.56) (two trials involving 145 participants). The RR for leaving the trial early was 1.02 (95% CI 0.86 to 1.21) in favour of control, with no heterogeneity between trials. There was a non-significant excess of seizures (RR 2.67; 95% CI 0.61 to 11.63) (seven trials involving 444 participants), a non-significant excess of gastrointestinal side effects (RR 1.90; 95% CI 0.94 to 3.85) (14 trials involving 902 participants) and a non-significant excess of bleeding (RR 1.63; 95% CI 0.20 to 13.05) (two trials involving 249 participants) in those allocated SSRIs. Data were not available on quality of life, fatigue or healthcare costs.There was no clear evidence from subgroup analyses that one SSRI was consistently superior to another, or that time since stroke or depression at baseline had a major influence on effect sizes. Sensitivity analyses suggested that effect sizes were smaller when we excluded trials at high or unclear risk of bias.Only eight trials provided data on outcomes after treatment had been completed; the effect sizes were generally in favour of SSRIs but CIs were wide.

AUTHORS' CONCLUSIONS

SSRIs appeared to improve dependence, disability, neurological impairment, anxiety and depression after stroke, but there was heterogeneity between trials and methodological limitations in a substantial proportion of the trials. Large, well-designed trials are now needed to determine whether SSRIs should be given routinely to patients with stroke.

Role of nonsynaptic GluN2B-containing NMDA receptors in excitotoxicity: evidence that fluoxetine selectively inhibits these receptors and may have neuroprotective effects

In acute ischaemic brain injury and chronic neurodegeneration, the primary step leading to excitotoxicity and cell death is the excessive and/or prolonged activation of glutamate (Glu) receptors, followed by intracellular calcium (Ca(2+)) overload. These steps lead to several effects: a persistent depolarisation of neurons, mitochondrial dysfunction resulting in energy failure, an increased production of reactive oxygen species (ROS), an increase in the concentration of cytosolic Ca(2+) [Ca(2+)]i, increased mitochondrial Ca(2+) uptake, and the activation of self-destructing enzymatic mechanisms. Antagonists for NMDA receptors (NMDARs) are expected to display neuroprotective effects, but no evidence to support this hypothesis has yet been reported. A number of clinical trials using NMDAR antagonists have failed to demonstrate neuroprotective effects, either by reducing brain injury or by preventing neurodegeneration. Recent advances in NMDAR research have provided an explanation for this phenomenon. Synaptic and extrasynaptic NMDARs are composed of different subunits (GluN2A and GluN2B) that demonstrate opposing effects. Synaptic GluN2A-containing and extrasynaptic GluN2B-containing NMDARs have different co-agonists: d-serine for synaptic NMDARs and glycine for extrasynaptic NMDARs. Both co-agonists are of glial origin. The mechanisms of cell destruction or cell survival in response to the activation of NMDAR receptors depend in part on [Ca(2+)]i and the route of entry of this ion and more significantly on the subunit composition and localisation of the NMDARs. While synaptic NMDAR activation is involved in neuroprotection, the stimulation of extrasynaptic NMDARs, which are composed of GluN2B subunits, triggers cell destruction pathways and may play a key role in the neurodegeneration associated with Glu-induced excitotoxicity. In addition, it has been found that synaptic and extrasynaptic NMDA receptors have opposing effects in determining the fate of neurons. This result has led to the targeting of nonsynaptic GluN2B-containing NMDARs as promising candidates for drug research. Under hypoxic conditions, it is likely that the failure of synaptic glutamatergic transmission, the impairment of the GluN2A-activated neuroprotective cascade, and the persistent over-activation of extrasynaptic GluN2B-containing NMDARs lead to excitotoxicity. Fluoxetine, a drug widely used in clinical practice as an antidepressant, has been found to selectively block GluNR2B-containing NMDARs. Therefore, it seems to be a potential candidate for neuroprotection.

Dynamic plasticity: the role of glucocorticoids, brain-derived neurotrophic factor and other trophic factors

Brain-derived neurotrophic factor (BDNF) is a secreted protein that has been linked to numerous aspects of plasticity in the central nervous system (CNS). Stress-induced remodeling of the hippocampus, prefrontal cortex and amygdala is coincident with changes in the levels of BDNF, which has been shown to act as a trophic factor facilitating the survival of existing and newly born neurons. Initially, hippocampal atrophy after chronic stress was associated with reduced BDNF, leading to the hypothesis that stress-related learning deficits resulted from suppressed hippocampal neurogenesis. However, recent evidence suggests that BDNF also plays a rapid and essential role in regulating synaptic plasticity, providing another mechanism through which BDNF can modulate learning and memory after a stressful event. Numerous reports have shown BDNF levels are highly dynamic in response to stress, and not only vary across brain regions but also fluctuate rapidly, both immediately after a stressor and over the course of a chronic stress paradigm. Yet, BDNF alone is not sufficient to effect many of the changes observed after stress. Glucocorticoids and other molecules have been shown to act in conjunction with BDNF to facilitate both the morphological and molecular changes that occur, particularly changes in spine density and gene expression. This review briefly summarizes the evidence supporting BDNF's role as a trophic factor modulating neuronal survival, and will primarily focus on the interactions between BDNF and other systems within the brain to facilitate synaptic plasticity. This growing body of evidence suggests a more nuanced role for BDNF in stress-related learning and memory, where it acts primarily as a facilitator of plasticity and is dependent upon the coactivation of glucocorticoids and other factors as the determinants of the final cellular response.

Probing modifications of cortical excitability during stroke recovery with navigated transcranial magnetic stimulation

OBJECTIVE

To follow cortical excitability changes during recovery from stroke with navigated transcranial magnetic stimulation (nTMS), in particular, to characterize changes of short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF), to correlate them with recovery of upper extremity function, and to detect possible shifts of cortical hand representations.

METHODS

Single and paired pulse nTMS were delivered to the hemisphere with infarction and to the hemisphere without infarction in 14 first-ever stroke patients at 1 (T1) and 3 months (T2) after stroke. Electromyographic responses to nTMS stimulation were recorded from the first dorsal interosseus muscles. nTMS was used to ensure an accurate coil repositioning in repeated measurements. Hand function recovery was clinically evaluated using the Action Research Arm Test (ARAT) and 9-hole peg test (9-HPT).

RESULTS

SICI and ICF were modulated in both hemispheres during recovery. Inhibition in the hemisphere without infarction correlated significantly with the affected hand performance at T2; stronger disinhibition (poor inhibition) was associated with worse hand performance. Location of hand muscle representations was shifted in 3 well-recovered patients out of 14 patients at T2.

CONCLUSIONS

In line with earlier studies, disinhibition in the hemisphere without infarction may be related to poor recovery of the affected hand. Usage of the affected hand during stroke recovery seems to influence these cortical excitability changes. nTMS is a valuable tool for tracking muscle cortical representation changes during brain reorganization.

GluN2B-containing NMDA receptors as possible targets for the neuroprotective and antidepressant effects of fluoxetine

Accumulating evidence has indicated the involvement of glutamatergic neurotransmission in the pathophysiology of excitotoxicity and in the mechanism of action of antidepressants. We have previously shown that tricyclic desipramine and the selective serotonin reuptake inhibitor fluoxetine inhibit NMDA receptors (NMDARs) in the clinically relevant, low micromolar concentration range. As the different subtypes of NMDARs are markedly different in their physiological and pathological functions, our aim was to investigate whether the effect of antidepressants is subtype-specific. Using whole-cell patch-clamp recordings in rat cortical cell cultures, we studied the age-dependence of inhibition of NMDA-induced currents after treatment with desipramine and fluoxetine, as the expression profile of the NMDAR subtypes changes as a function of days in vitro. We also investigated the inhibitory effect of these antidepressants on NMDA-induced currents in HEK 293 cell lines that stably expressed rat recombinant NMDARs with GluN1a/GluN2A or GluN1a/GluN2B subunit compositions. The inhibitory effect of desipramine was not age-dependent, whereas fluoxetine displayed a continuously decreasing inhibitory profile, which was similar to the GluN1/GluN2B subtype-selective antagonist ifenprodil. In HEK 293 cells, desipramine equally inhibited NMDA currents in both cell lines, whereas fluoxetine showed an inhibitory effect only in cells that expressed the GluN1/GluN2B subtype. Our data show that fluoxetine is a selective inhibitor of GluN2B-containing NMDARs, whereas desipramine inhibits both GluN1/GluN2A and GluN1/GluN2B subtypes. As the clinical efficacy of these drugs is very similar, the putative NMDAR-associated therapeutic effect of antidepressants may be mediated only via inhibition of the GluN2B-containing subtype. The manifestation of the GluN1/GluN2B-selectivity of fluoxetine suggests the neuroprotective potential for this drug in both acute and chronic neurodegenerative disorders.

Effect of antidepressants on the course of disability following stroke

OBJECTIVE

Stroke often produces marked physical and cognitive impairments leading to functional dependence, caregiver burden, and poor quality of life. We examined the course of disability during a 1-year follow-up period after stroke among patients who were administered antidepressants for 3 months compared to patients given placebo for 3 months.

METHODS

A total of 83 patients entered a double-blind randomized study of the efficacy of antidepressants to treat depressive disorders and reduce disability after stroke. Patients were assigned to either fluoxetine (N = 32), nortriptyline (N = 22) or placebo (N = 29). Psychiatric assessment included administration of the Present State Examination modified to identify DSM-IV symptoms of depression. The severity of depression was measured using the 17-item Hamilton Depression Rating Scale. The modified Rankin Scale was used to evaluate the disability of patients at initial evaluation and at quarterly follow-up visits for 1 year. Impairment in activities of daily living was assessed by Functional Independence Measure at the same time.

RESULTS

During the 1-year follow-up period, and after adjusting for critical confounders including age, intensity of rehabilitation therapy, baseline stroke severity, and baseline Hamilton Depression Rating Scale, patients who received fluoxetine or nortriptyline had significantly greater improvement in modified Rankin Scale scores compared to patients who received placebo (t [156] = -3.17, p = 0.002).

CONCLUSIONS

Patients treated with antidepressants had better recovery from disability by 1-year post stroke (i.e., 9 months after antidepressants were stopped) than patients who did not receive antidepressant therapy. This effect was independent of depression suggesting that antidepressants may facilitate the neural mechanisms of recovery in patients with stroke.

Long-term administration of fluoxetine to improve motor recovery after stroke

Evaluation of: Chollet F Tardy J, Albucher JF et al. Fluoxetine for motor recovery after acute ischaemic stroke (FLAME): a randomised placebo-controlled trial. Lancet Neurol. 10(2), 123–130 (2011). In this study, the authors examined the effects of administration of fluoxetine for 90 days on the recovery of motor function in acute stroke patients. They found that motor function in the group receiving fluoxetine improved significantly compared with the control group. Before administration of fluoxetine can be used as a new therapeutic treatment to improve the rehabilitation after stroke, the long-term effects in chronic stroke patients, as well as the physiological effects, have to be studied and compared with the results of other neuropharmacalogical agents.

Fluoxetine for motor recovery after acute ischaemic stroke (FLAME): a randomised placebo-controlled trial

BACKGROUND

Hemiplegia and hemiparesis are the most common deficits caused by stroke. A few small clinical trials suggest that fluoxetine enhances motor recovery but its clinical efficacy is unknown. We therefore aimed to investigate whether fluoxetine would enhance motor recovery if given soon after an ischaemic stroke to patients who have motor deficits.

METHODS

In this double-blind, placebo-controlled trial, patients from nine stroke centres in France who had ischaemic stroke and hemiplegia or hemiparesis, had Fugl-Meyer motor scale (FMMS) scores of 55 or less, and were aged between 18 years and 85 years were eligible for inclusion. Patients were randomly assigned, using a computer random-number generator, in a 1:1 ratio to fluoxetine (20 mg once per day, orally) or placebo for 3 months starting 5-10 days after the onset of stroke. All patients had physiotherapy. The primary outcome measure was the change on the FMMS between day 0 and day 90 after the start of the study drug. Participants, carers, and physicians assessing the outcome were masked to group assignment. Analysis was of all patients for whom data were available (full analysis set). This trial is registered with ClinicalTrials.gov, number NCT00657163.

FINDINGS

118 patients were randomly assigned to fluoxetine (n=59) or placebo (n=59), and 113 were included in the analysis (57 in the fluoxetine group and 56 in the placebo group). Two patients died before day 90 and three withdrew from the study. FMMS improvement at day 90 was significantly greater in the fluoxetine group (adjusted mean 34·0 points [95% CI 29·7-38·4]) than in the placebo group (24·3 points [19·9-28·7]; p=0·003). The main adverse events in the fluoxetine and placebo groups were hyponatraemia (two [4%] vs two [4%]), transient digestive disorders including nausea, diarrhoea, and abdominal pain (14 [25%] vs six [11%]), hepatic enzyme disorders (five [9%] vs ten [18%]), psychiatric disorders (three [5%] vs four [7%]), insomnia (19 [33%] vs 20 [36%]), and partial seizure (one [<1%] vs 0).

INTERPRETATION

In patients with ischaemic stroke and moderate to severe motor deficit, the early prescription of fluoxetine with physiotherapy enhanced motor recovery after 3 months. Modulation of spontaneous brain plasticity by drugs is a promising pathway for treatment of patients with ischaemic stroke and moderate to severe motor deficit.

FUNDING

Public French National Programme for Clinical Research.

Advances in cerebrovascular disease research in the last year

The following review summarizes the progress in cerebrovascular disease research published in the Journal of Neurology in the last year.

Pharmacological augmentation of motor recovery after stroke: antidepressants for non-depressed patients?

Stroke remains the most common cause of adult physical disability worldwide, and standard physical rehabilitation methods have limited effectiveness. Thus, the possibility of augmenting motor recovery after stroke using drugs has obvious attractions.