Beta-2 receptor antagonists for traumatic brain injury: a systematic review of controlled trials in animal models

Seeding cell approach for tissue-engineered urethral reconstruction in animal study: A systematic review and meta-analysis

We systematically reviewed published preclinical studies to evaluate the effectiveness of cell-seeded tissue engineering approach for urethral reconstruction in an animal model. The outcomes were summarized by success factors in the animal experiments, which evaluate the possibility and feasibility of a clinical application in the future. Preclinical studies of tissue engineering approaches for urethral reconstruction were identified through a systematic search in PubMed, Embase, and Biosis Previews (web of science SP) databases for studies published from 1 January 1980 to 23 November 2014. Primary studies were included if urethral reconstruction was performed using a tissue-engineered biomaterial in any animal species (with the experiment group being a cell-seeded scaffold and the control group being a cell-free scaffold) with histology and urethrography as the outcome measure. A total of 15 preclinical studies were included in our meta-analysis. The histology and urethrography outcome between the experimental and control groups were considered to be the most clinically relevant. Through this systematic approach, our outcomes suggested that applying the cell-seeded biomaterial in creating a neo-urethra was stable and effective. And multi-type cells including epithelial cells as well as smooth muscle cells or fibroblasts seemed to be a better strategy. Stem cells, especially after epithelial differentiation, could be a promising choice for future researches.

Evidence-based review of oral traditional Chinese medicine compound recipe administration for treating weight drop-induced experimental traumatic brain injury

BACKGROUND

Recently, a number of studies conducted and published in China have suggested that traditional Chinese medicine compound recipe (TCMCR) may be beneficial in the treatment of experimental traumatic brain injury (TBI). In this study, we conducted a systematic review and meta-analysis of the efficacy of TCMCR in TBI model with weight drop method to provide robust evidence on the effects of TCMCR and to determine whether TCMCR can be recommended for routine treatment or considered as a standard treatment for TBI.

METHODS

We identified eligible studies by searching five electronic databases on April 1, 2014, and pooled the data using the random-effects model. Results were reported in terms of standardized mean difference (SMD). We also calculated statistical heterogeneity, evaluated the studies' methodological quality and investigated the presence of publication bias.

RESULTS

Totally, 187 relevant publications were searched from databases, 25 of which met our inclusion criteria. The overall methodological quality of the most studies was poor, and there was evidence of statistical heterogeneity among studies along with small-study effects. Meta-analysis showed statistically significant effects indicating that TCMCR has a beneficial effect on TBI.

CONCLUSIONS

Despite the limitations, we concluded that TCMCR may reduce brain water content, improve BBB permeability, and decrease TNF-α/NO expression after experimental TBI in terms of overall efficacy. However, our review also indicates that more well-designed and well-reported animal studies are needed.

Catecholaminergic based therapies for functional recovery after TBI

Among the many pathophysiologic consequences of traumatic brain injury are changes in catecholamines, including dopamine, epinephrine, and norepinephrine. In the context of TBI, dopamine is the one most extensively studied, though some research exploring epinephrine and norepinephrine have also been published. The purpose of this review is to summarize the evidence surrounding use of drugs that target the catecholaminergic system on pathophysiological and functional outcomes of TBI using published evidence from pre-clinical and clinical brain injury studies. Evidence of the effects of specific drugs that target catecholamines as agonists or antagonists will be discussed. Taken together, available evidence suggests that therapies targeting the catecholaminergic system may attenuate functional deficits after TBI. Notably, it is fairly common for TBI patients to be treated with catecholamine agonists for either physiological symptoms of TBI (e.g. altered cerebral perfusion pressures) or a co-occuring condition (e.g. shock), or cognitive symptoms (e.g. attentional and arousal deficits). Previous clinical trials are limited by methodological limitations, failure to replicate findings, challenges translating therapies to clinical practice, the complexity or lack of specificity of catecholamine receptors, as well as potentially counfounding effects of personal and genetic factors. Overall, there is a need for additional research evidence, along with a need for systematic dissemination of important study details and results as outlined in the common data elements published by the National Institute of Neurological Diseases and Stroke. Ultimately, a better understanding of catecholamines in the context of TBI may lead to therapeutic advancements. This article is part of a Special Issue entitled SI:Brain injury and recovery.

Effects of stem cell transplantation on cognitive decline in animal models of Alzheimer's disease: A systematic review and meta-analysis

Alzheimer’s disease (AD), an irreversible progressive neurodegenerative disease, causes characteristic cognitive impairment, and no curative treatments are currently available. Stem cell transplantation offers a powerful tool for the treatment of AD. We conducted a systematic review and meta-analysis of data from controlled studies to study the impact of stem cell biology and experimental design on learning and memory function following stem cell transplantation in animal models of AD. A total of 58 eligible controlled studies were included by searching PubMed, EMBASE, and Web of Science up to April 13, 2015. Meta-analysis showed that stem cell transplantation could promote both learning and memory recovery. Stratified meta-analysis was used to explore the influence of the potential factors on the estimated effect size, and meta-regression analyses were undertaken to explore the sources of heterogeneity for learning and memory function. Publication bias was assessed using funnel plots and Egger’s test. The present review reinforces the evidence supporting stem cell transplantation in experimental AD. However, it highlights areas that require well-designed and well-reported animal studies.

Systematic review and meta-analysis of efficacy of mesenchymal stem cells on locomotor recovery in animal models of traumatic brain injury

Introduction

The therapeutic potential of mesenchymal stem cells (MSCs) for traumatic brain injury (TBI) is attractive. Conducting systematic review and meta-analyses based on data from animal studies can be used to inform clinical trial design. To conduct a systematic review and meta-analysis to (i) systematically review the literatures describing the effect of MSCs therapy in animal models of TBI, (ii) determine the estimated effect size of functional locomotor recovery after experimental TBI, and (iii) to provide empirical evidence of biological factors associated with greater efficacy.

Methods

We conducted a systematic search of PubMed, EMBASE, and Web of Science and hand searched related references. Studies were selected if they reported the efficacy of MSCs in animal models of TBI. Two investigators independently assessed the identified studies. We extracted the details of individual study characteristics from each publication, assessed study quality, evaluated the effect sizes of MSCs treatment, and performed stratified meta-analysis and meta-regression, to assess the influence of study design on the estimated effect size. The presence of small effect sizes was investigated using funnel plots and Egger’s tests.

Results

Twenty-eight eligible controlled studies were identified. The study quality was modest. Between-study heterogeneity was large. Meta-analysis showed that MSCs exert statistically significant positive effects on sensorimotor and neurological motor function. For sensorimotor function, maximum effect size in studies with a quality score of 5 was found in the weight-drop impact injury TBI model established in male SD rats, to which syngeneic umbilical cord-derived MSCs intracerebrally at cell dose of (1–5) × 10⁶ was administered r 6 hours following TBI, using ketamine as anesthetic agent. For neurological motor function, effect size was maximum for studies with a quality score of 5, in which the weight-drop impact injury TBI models of the female Wistar rats were adopted, with administration syngeneic bone marrow-derived MSCs intravenously at cell dose of 5 × 10⁶ at 2 months after TBI, using sevofluorane as anesthetic agent.

Conclusions

We conclude that MSCs therapy may improve locomotor recovery after TBI. However, additional well-designed and well-reported animal studies are needed to guide further clinical studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-015-0034-0) contains supplementary material, which is available to authorized users.

β-blockers in critically ill patients: from physiology to clinical evidence

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2015 and co-published as a series in Critical Care. Other articles in the series can be found online at http://ccforum.com/series/annualupdate2015. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

The use of systematic reviews and reporting guidelines to advance the implementation of the 3Rs

In 1959, Russell and Burch published The Principles of Humane Experimental Technique, which included concrete advice on factors that they considered would govern progress in the implementation of these principles (enunciated as the 3Rs [Replacement, Reduction, and Refinement in animal-based studies]). One challenge to the implementation of the 3Rs was identified as information retrieval. Here, we further explore this challenge-the need for 'research on research'-and the role that systematic reviews and reporting guidelines can play in implementation of the 3Rs. First, we examine the 2-fold nature of the challenge of information retrieval: 1) the identification of relevant publications spread throughout a large population of nonrelevant publications and 2) the incomplete reporting of relevant details within those publications. Second, we evaluate how systematic reviews and reporting guidelines can be used generally to address this challenge. Third, we assess the explicit reporting of the 3Rs in a cohort of preclinical animal systematic reviews. Our results show that Reduction methods are the most commonly reported by authors of systematic reviews but that, in general, reporting on how findings relate to the 3Rs is limited at best. Although systematic reviews are excellent tools for resolving the challenge of information retrieval, their utility for making progress in implementation of the 3Rs may be limited unless authors improve their reporting of these principles.

Infantile hemangiomas, retinopathy of prematurity and cancer: a common pathogenetic role of the β-adrenergic system

The serendipitous demonstration that the nonselective β-adrenergic receptor (β-AR) antagonist propranolol promotes the regression of infantile hemangiomas (IHs) aroused interest around the involvement of the β-adrenergic system in angiogenic processes. The efficacy of propranolol was related to the β2-AR blockade and the consequent inhibition of the production of vascular endothelial growth factor (VEGF), suggesting the hypothesis that propranolol could also be effective in treating retinopathy of prematurity (ROP), a retinal pathology characterized by VEGF-induced neoangiogenesis. Consequent to the encouraging animal studies, a pilot clinical trial showed that oral propranolol protects newborns from ROP progression, even though this treatment is not sufficiently safe. Further, animal studies clarified the role of β3-ARs in the development of ROP and, together with several preclinical studies demonstrating the key role of the β-adrenergic system in tumor progression, vascularization, and metastasis, prompted us to also investigate the participation of β3-ARs in tumor growth. The aim of this review is to gather the recent findings on the role of the β-adrenergic system in IHs, ROP, and cancer, highlighting the fact that these different pathologies, triggered by different pathogenic noxae, share common pathogenic mechanisms characterized by the presence of hypoxia-induced angiogenesis, which may be contrasted by targeting the β-adrenergic system. The mechanisms characterizing the pathogenesis of IHs, ROP, and cancer may also be active during the fetal-neonatal development, and a great contribution to the knowledge on the role of β-ARs in diseases characterized by chronic hypoxia may come from research focusing on the fetal and neonatal period.

Impact of statins on cognitive deficits in adult male rodents after traumatic brain injury: a systematic review

The efficacy of statin treatment on cognitive decline is controversial, and the effect of statins on cognitive deficits in individuals with traumatic brain injury (TBI) has yet to be investigated. Therefore, we systematically reviewed the effect of statins on cognitive deficits in adult male rodents after TBI. After identifying eligible studies by searching four electronic databases on February 28, 2014, we assessed study quality, evaluated the efficacy of statin treatment, and performed stratified metaregression and metaregression to assess the influence of study design on statin efficacy. Eleven studies fulfilled our inclusion criteria from a total of 183 publications. The overall methodological quality of these studies was poor. Meta-analysis showed that statins exert statistically significant positive effects on cognitive performance after TBI. Stratified analysis showed that atorvastatin has the greatest effect on acquisition memory, simvastatin has the greatest effect on retention memory, and statin effects on acquisition memory are higher in closed head injury models. Metaregression analysis further showed that that animal species, study quality, and anesthetic agent impact statin effects on retention memory. We conclude that statins might reduce cognitive deficits after TBI. However, additional well-designed and well-reported animal studies are needed to inform further clinical study.

The efficacy of erythropoietin in treating experimental traumatic brain injury: a systematic review of controlled trials in animal models

OBJECT

Erythropoietin (EPO) shows promise as a neuroprotective agent in animal models of traumatic brain injury (TBI). However, clinical trials of the efficacy of EPO treatment in patients with TBI yield conflicting results. The authors conducted a systematic review and meta-analysis to assess the effect of EPO in experimental animal models of TBI, the goal being to inform the design of future clinical trials.

METHODS

The authors identified eligible studies by searching PubMed, Web of Science, MEDLINE, Embase, and Google Scholar in October 2013. Data were pooled using the random-effects model, and results were reported in terms of standardized mean difference. Statistical heterogeneity was examined using both I(2) and chi-square tests, and the presence of small study effects was investigated with funnel plots and Egger tests. In-depth analyses were performed for lesion volume and neurobehavioral outcome, and the studies' methodological quality was also evaluated.

RESULTS

Of a total of 290 studies, 13 found an effect of EPO on lesion volume and neurobehavioral outcome. Overall, the methodological quality of the studies was poor, and there was evidence of statistical heterogeneity among the publications as well as small-study effects. However, in-depth analyses showed statistically significant findings in favor of a beneficial effect of EPO after TBI.

CONCLUSIONS

Despite limitations of this systematic review that may have influenced the findings, the authors conclude that EPO might be beneficial in treating experimental TBI in terms of reducing lesion volume and improving neurobehavioral outcome. However, this review also indicates that more well-designed and well-reported animal studies are needed.

Advances in the management of the critically injured patient in the operating room

Care of trauma patients continues to improve through better understanding of optimal timing of operating room (OR) interventions, improved monitoring for patients with head injury and hemodynamic compromise, optimization of volume status, and use of appropriate vasoactive agents. Investigation of the pathophysiology of trauma patients as they progress to the chronic phase continues to advance interventions in the ICU and the OR. This article is an evidence-based update of anesthetic considerations for these patients, including management of intracranial pressure, cardiac monitoring, management of the damage control abdomen, fluid and hemodynamic management, and control of coagulopathies.

Neuroprotective effects of selective β-1 adrenoceptor antagonists, landiolol and esmolol, on transient forebrain ischemia in rats; a dose-response study

Although selective beta-1 adrenoceptor antagonists are known to provide neuroprotective effects after brain ischemia, dose-response relationships of their neuroprotective effects have not been examined. The present study was conducted to evaluate whether the degree of brain protection against transient forebrain ischemia would be influenced by different doses of selective beta-1 adrenoceptor antagonists, esmolol and landiolol, in rats. Adult male S.D. rats received intravenous infusion of saline 0.5 ml/h, esmolol 20, 200, 2,000 μg/kg/min, or landiolol 5, 50, 500 μg/kg/min. Infusion was initiated 30 min prior to ischemia and continued for 24h. Ten-minute forebrain ischemia was induced by hemorrhagic hypotension and occlusion of the bilateral carotid arteries. Neurological and histological examinations were performed. Neurological deficit scores at 1, 4 and 7 days were lower, and the number of intact neurons in CA1 hippocampal region was larger in the rats treated with esmolol and landiolol after ischemia, compared with saline-treated rats (P<0.05), whereas no difference was found among different doses of esmolol and landiolol. These results suggested that selective beta-1 adrenoceptor antagonists improved neurological and histological outcomes following forebrain ischemia in rats, irrespective of their doses.

Baroreflex Sensitivity to Predict Malignant Middle Cerebral Artery Infarction

Background and Purpose—

Hemicraniectomy has been shown to be an effective treatment of life-threatening edema (LTE) in malignant middle cerebral artery infarction when performed early. Identifying patients who will develop LTE is therefore imperative. We hypothesize that autonomic shift toward sympathetic dominance may relate to LTE formation. We aimed to investigate the predictive potential of baroreflex sensitivity (BRS) as a marker of autonomic balance for calculating the course of large middle cerebral artery infarction.

Methods—

Patients with middle cerebral artery infarction >2/3 of the territory and BRS measurement at admission were analyzed. BRS was estimated using the cross-correlational method. Demographic, clinical, and radiological data including stroke severity, infarct size, and basal ganglia involvement were recorded. Malignant course with LTE was defined as clinical deterioration and midline shift ≥5 mm in the first 48 hours.

Results—

Eighteen (62.8%) patients developed LTE. Patients with LTE had lower BRS (2.3 versus 4.4 mm Hg/ms, P =0.007), larger infarcts (214 versus 144 mL, P =0.03), more frequent involvement of the basal ganglia (14 versus 4, P =0.03), and more often underwent thrombolysis combined with endovascular intervention (6 versus 0, P =0.04). In a multivariate model, BRS (OR, 0.36; CI, 0.14–0.93; P =0.03) and basal ganglia involvement (OR, 11.53; CI, 1.15–115.9; P =0.04) were independent predictors for LTE. This model correctly classified 86.2% of the malignant cases.

Conclusions—

Decreased BRS, mirroring sympathetic activation, and basal ganglia involvement were associated with development of malignant course with LTE in large middle cerebral artery infarction. The predictive relevance of our findings needs to be confirmed in further studies.

The BRAIN TRIAL: a randomised, placebo controlled trial of a Bradykinin B2 receptor antagonist (Anatibant) in patients with traumatic brain injury

Background

Cerebral oedema is associated with significant neurological damage in patients with traumatic brain injury. Bradykinin is an inflammatory mediator that may contribute to cerebral oedema by increasing the permeability of the blood-brain barrier. We evaluated the safety and effectiveness of the non-peptide bradykinin B2 receptor antagonist Anatibant in the treatment of patients with traumatic brain injury. During the course of the trial, funding was withdrawn by the sponsor.

Methods

Adults with traumatic brain injury and a Glasgow Coma Scale score of 12 or less, who had a CT scan showing an intracranial abnormality consistent with trauma, and were within eight hours of their injury were randomly allocated to low, medium or high dose Anatibant or to placebo. Outcomes were Serious Adverse Events (SAE), mortality 15 days following injury and in-hospital morbidity assessed by the Glasgow Coma Scale (GCS), the Disability Rating Scale (DRS) and a modified version of the Oxford Handicap Scale (HIREOS).

Results

228 patients out of a planned sample size of 400 patients were randomised. The risk of experiencing one or more SAEs was 26.4% (43/163) in the combined Anatibant treated group, compared to 19.3% (11/57) in the placebo group (relative risk = 1.37; 95% CI 0·76 to 2·46). All cause mortality in the Anatibant treated group was 19% and in the placebo group 15.8% (relative risk 1.20, 95% CI 0.61 to 2.36). The mean GCS at discharge was 12.48 in the Anatibant treated group and 13.0 in the placebo group. Mean DRS was 11.18 Anatibant versus 9.73 placebo, and mean HIREOS was 3.94 Anatibant versus 3.54 placebo. The differences between the mean levels for GCS, DRS and HIREOS in the Anatibant and placebo groups, when adjusted for baseline GCS, showed a non-significant trend for worse outcomes in all three measures.

Conclusion

This trial did not reach the planned sample size of 400 patients and consequently, the study power to detect an increase in the risk of serious adverse events was reduced. This trial provides no reliable evidence of benefit or harm and a larger trial would be needed to establish safety and effectiveness.

Trial Registration

This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN23625128.

Pharmacotherapy to enhance arousal: what is known and what is not

Severe brain injury results in a disturbance among a wide range of critical neurotransmitter systems. Each neurotransmitter system places its own functional role while being interconnected to a multitude of other systems and functions. This chapter seeks to review the major neurotransmitter systems involved after severe acquired brain injury. While limited in their construct, animal models of brain injury have demonstrated agents that may assist in the recovery process and those that may further slow recovery. We review further the issue of laboratory evidence and what is transferable to the clinic. Lastly, this chapter reviews published clinical pharmacotherapy studies or trials in the arena of arousal for those with clinical severe brain injury. We discuss limitations as well as findings and present the available evidence in a table-based format. While no clear evidence exists to suggest a defined and rigid pharmacotherapeutic approach, interesting data does suggest that several medications have been associated with enhanced arousal. Several studies are underway or about to begin that will shed more light on the utility of such agents in improving function after severe brain injury. For now, clinicians must employ their own judgment and what has been learned from the limited literature to the care of a challenging group of persons.