Validity of the brief executive-function assessment tool in an outpatient substance use disorder setting.

The Brief Executive-function Assessment Tool (BEAT) was developed and validated for use in residential substance use disorder treatment settings, where participants are mostly abstinent. It is therefore unclear whether the BEAT is valid for use in outpatient settings, where participants may be actively using substances. The effects of acute intoxication and withdrawal have the potential to alter the results of the BEAT. The current study sought to establish construct and criterion validity of the BEAT in an outpatient substance use disorder sample and to detect its sensitivity to substance use over the previous 24 hours and also over the past month. A total of 74 clients of a New South Wales-based outpatient substance use disorder service participated in the current study. Construct validity was demonstrated by significant correlations between the BEAT and three performance-based tests of executive functioning. Criterion validity was established in that the BEAT discriminated between those deemed impaired or not on a criterion composite measure of executive functioning. Test operating characteristics (88% sensitivity, 69% specificity, 44% PPV, and 95% NPV) were also established relative to this composite measure as a reference standard. The BEAT was insensitive to use/abstinence over the previous 24 hours and the past month.

Brief executive-function assessment tool: A new cognitive impairment screening tool for alcohol and other drug services.

Accurate screening for cognitive impairment in alcohol and other drug (AOD) services would help to identify individuals who may need supports to obtain the greatest benefit from substance use disorder (SUD) treatment. At present there is no screening measure that has been developed specifically to detect cognitive impairment in a SUD population. This study examines the psychometric properties of the Brief Executive-function Assessment Tool (BEAT), which was specifically designed for this purpose. This study involving 501 individuals with SUD and 145 normal control participants established internal consistency (n = 646; 0.734), interrater (n = 60; 0.994), and test-retest reliability (n = 177; 0.845), and construct (all correlations p ≤ 0.05), and criterion (n = 467; ANCOVA p < 0.001) validity. Test operating characteristics (n = 500; 87% sensitivity, 71% specificity, 21% PPP, and 99% NPP) were also established relative to an independent criterion variable made up of three established performance-based neuropsychological tests. Findings support the reliability and validity of the BEAT as a screening measure of executive function impairment with high sensitivity and a low rate of false negatives.

Multisensory enhancement of attention depends on whether you are already paying attention.

Multisensory stimuli are argued to capture attention more effectively than unisensory stimuli due to their ability to elicit a super-additive neuronal response. However, behavioural evidence for enhanced multisensory attentional capture is mixed. Furthermore, the notion of multisensory enhancement of attention conflicts with findings suggesting that multisensory integration may itself be dependent upon top-down attention. The present research resolves this discrepancy by examining how both endogenous attentional settings and the availability of attentional capacity modulate capture by multisensory stimuli. Across a series of four studies, two measures of attentional capture were used which vary in their reliance on endogenous attention: facilitation and distraction. Perceptual load was additionally manipulated to determine whether multisensory stimuli are still able to capture attention when attention is occupied by a demanding primary task. Multisensory stimuli presented as search targets were consistently detected faster than unisensory stimuli regardless of perceptual load, although they are nevertheless subject to load modulation. In contrast, task irrelevant multisensory stimuli did not cause greater distraction than unisensory stimuli, suggesting that the enhanced attentional status of multisensory stimuli may be mediated by the availability of endogenous attention. Implications for multisensory alerts in practical settings such as driving and aviation are discussed, namely that these may be advantageous during demanding tasks, but may be less suitable to signaling unexpected events.

Human Cortical Neural Stem Cells Expressing Insulin-Like Growth Factor-I: A Novel Cellular Therapy for Alzheimer's Disease.

Alzheimer's disease (AD) is the most prevalent age-related neurodegenerative disorder and a leading cause of dementia. Current treatment fails to modify underlying disease pathologies and very little progress has been made to develop effective drug treatments. Cellular therapies impact disease by multiple mechanisms, providing increased efficacy compared with traditional single-target approaches. In amyotrophic lateral sclerosis, we have shown that transplanted spinal neural stem cells (NSCs) integrate into the spinal cord, form synapses with the host, improve inflammation, and reduce disease-associated pathologies. Our current goal is to develop a similar "best in class" cellular therapy for AD. Here, we characterize a novel human cortex-derived NSC line modified to express insulin-like growth factor-I (IGF-I), HK532-IGF-I. Because IGF-I promotes neurogenesis and synaptogenesis in vivo, this enhanced NSC line offers additional environmental enrichment, enhanced neuroprotection, and a multifaceted approach to treating complex AD pathologies. We show that autocrine IGF-I production does not impact the cell secretome or normal cellular functions, including proliferation, migration, or maintenance of progenitor status. However, HK532-IGF-I cells preferentially differentiate into gamma-aminobutyric acid-ergic neurons, a subtype dysregulated in AD; produce increased vascular endothelial growth factor levels; and display an increased neuroprotective capacity in vitro. We also demonstrate that HK532-IGF-I cells survive peri-hippocampal transplantation in a murine AD model and exhibit long-term persistence in targeted brain areas. In conclusion, we believe that harnessing the benefits of cellular and IGF-I therapies together will provide the optimal therapeutic benefit to patients, and our findings support further preclinical development of HK532-IGF-I cells into a disease-modifying intervention for AD.

Expression of microRNAs in human post-mortem amyotrophic lateral sclerosis spinal cords provides insight into disease mechanisms.

Amyotrophic lateral sclerosis is a late-onset and terminal neurodegenerative disease. The majority of cases are sporadic with unknown causes and only a small number of cases are genetically linked. Recent evidence suggests that post-transcriptional regulation and epigenetic mechanisms, such as microRNAs, underlie the onset and progression of neurodegenerative disorders; therefore, altered microRNA expression may result in the dysregulation of key genes and biological pathways that contribute to the development of sporadic amyotrophic lateral sclerosis. Using systems biology analyses on postmortem human spinal cord tissue, we identified dysregulated mature microRNAs and their potential targets previously implicated in functional process and pathways associated with the pathogenesis of ALS. Furthermore, we report a global reduction of mature microRNAs, alterations in microRNA processing, and support for a role of the nucleotide binding protein, TAR DNA binding protein 43, in regulating sporadic amyotrophic lateral sclerosis-associated microRNAs, thereby offering a potential underlying mechanism for sporadic amyotrophic lateral sclerosis.

Prevalence of founder mutations in the BRCA1 and BRCA2 genes among unaffected women from the Bahamas.

Population-based testing for BRCA1/2 mutations detects a high proportion of carriers not identified by cancer family history-based testing. We sought to determine whether population-based testing is an effective approach to genetic testing in the Bahamas, where 23% of women with breast cancer carry one of seven founder mutations in the BRCA1 or BRCA2 gene. We determined the prevalence of founder BRCA mutations in 1847 Bahamian women without a personal history of breast or ovarian cancer, unselected for age or family history. We found that 2.8% (20/705) of unaffected women with a family history of breast/ovarian cancer and 0.09% (1/1089) of unaffected women without a family history carry a BRCA mutation. A total of 38% of unaffected women with a known mutation in the family were found to carry the familial mutation. We previously suggested that all Bahamian women with breast or ovarian cancer be offered genetic testing. These current data suggest that additionally all unaffected Bahamian women with a family history of breast/ovarian cancer should be offered genetic testing for the founder BRCA mutations.

Strategies for recruitment of relatives of BRCA mutation carriers to a genetic testing program in the Bahamas.

The prevalence of BRCA1 and BRCA2 mutations among unselected breast cancer patients in the Bahamas is 23%. It is beneficial to advise relatives of mutation carriers that they are candidates for genetic testing. Women who test positive are then eligible for preventive interventions, such as oophorectomy. It is not clear how often relatives of women with a mutation in the Bahamas wish to undergo genetic testing for the family mutation. Furthermore, it is not clear how best to communicate this sensitive information to relatives in order to maximize patient compliance. We offered genetic testing to 202 first-degree relatives of 58 mutation carriers. Of 159 women who were contacted by the proband or other family member, only 14 made an appointment for genetic testing (9%). In contrast, among 32 relatives who were contacted directly by the genetic counselor, 27 came for an appointment (84%). This study suggests that for recruitment of relatives in the Bahamas, direct contact by counselor is preferable to using the proband as an intermediary.

Autocrine production of IGF-I increases stem cell-mediated neuroprotection.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder resulting in motor neuron (MN) loss. There are currently no effective therapies; however, cellular therapies using neural progenitor cells protect MNs and attenuate disease progression in G93A-SOD1 ALS rats. Recently, we completed a phase I clinical trial examining intraspinal human spinal stem cell (HSSC) transplantation in ALS patients which demonstrated our approach was safe and feasible, supporting the phase II trial currently in progress. In parallel, efforts focused on understanding the mechanisms underlying the preclinical benefit of HSSCs in vitro and in animal models of ALS led us to investigate how insulin-like growth factor-I (IGF-I) production contributes to cellular therapy neuroprotection. IGF-I is a potent growth factor with proven efficacy in preclinical ALS studies, and we contend that autocrine IGF-I production may enhance the salutary effects of HSSCs. By comparing the biological properties of HSSCs to HSSCs expressing sixfold higher levels of IGF-I, we demonstrate that IGF-I production augments the production of glial-derived neurotrophic factor and accelerates neurite outgrowth without adversely affecting HSSC proliferation or terminal differentiation. Furthermore, we demonstrate that increased IGF-I induces more potent MN protection from excitotoxicity via both indirect and direct mechanisms, as demonstrated using hanging inserts with primary MNs or by culturing with organotypic spinal cord slices, respectively. These findings support our theory that combining autocrine growth factor production with HSSC transplantation may offer a novel means to achieve additive neuroprotection in ALS.

Concise review: Stem cell therapies for amyotrophic lateral sclerosis: recent advances and prospects for the future.

Amyotrophic lateral sclerosis (ALS) is a lethal disease involving the loss of motor neurons. Although the mechanisms responsible for motor neuron degeneration in ALS remain elusive, the development of stem cell-based therapies for the treatment of ALS has gained widespread support. Here, we review the types of stem cells being considered for therapeutic applications in ALS, and emphasize recent preclinical advances that provide supportive rationale for clinical translation. We also discuss early trials from around the world translating cellular therapies to ALS patients, and offer important considerations for future clinical trial design. Although clinical translation is still in its infancy, and additional insight into the mechanisms underlying therapeutic efficacy and the establishment of long-term safety are required, these studies represent an important first step toward the development of effective cellular therapies for the treatment of ALS.

The spectrum of BRCA1 and BRCA2 mutations in breast cancer patients in the Bahamas.

We sought to identify the full range of founder mutations in BRCA1 and BRCA2 in the Bahamas and to estimate the proportion of all BRCA1 and BRCA2 mutations that are accounted for by founder mutations. We studied 214 Bahamian women with invasive breast cancer, unselected for age or family history. A founder mutation had previously been identified in 49 patients. We conducted full sequencing of the BRCA1 and BRCA2 genes and multiplex ligation-dependent probe amplification (MLPA) for 156 patients. A novel founder mutation in BRCA2 (exon 17 818delA) was seen in four different patients and five other unique mutations in BRCA1 and BRCA2, including a large deletion (exons 8-9) in BRCA1. In total, a mutation was seen in 58 of the 214 patients (27%); 92% of carriers carried one of the seven founder mutations. Approximately 27% of unselected cases of breast cancer in the Bahamian population are attributable to a mutation in BRCA1 or BRCA2, a prevalence which far exceeds that of any other country. The majority of women who carry a mutation in the Bahamas, carry one of the seven founder mutations, making it possible to offer genetic testing to all women at risk for breast cancer in the Bahamas.

Neuromuscular effects of G93A-SOD1 expression in zebrafish.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a fatal disorder involving the degeneration and loss of motor neurons. The mechanisms of motor neuron loss in ALS are unknown and there are no effective treatments. Defects in the distal axon and at the neuromuscular junction are early events in the disease course, and zebrafish provide a promising in vivo system to examine cellular mechanisms and treatments for these events in ALS pathogenesis. RESULTS: We demonstrate that transient genetic manipulation of zebrafish to express G93A-SOD1, a mutation associated with familial ALS, results in early defects in motor neuron outgrowth and axonal branching. This is consistent with previous reports on motor neuron axonal defects associated with familial ALS genes following knockdown or mutant protein overexpression. We also demonstrate that upregulation of growth factor signaling is capable of rescuing these early defects, validating the potential of the model for therapeutic discovery. We generated stable transgenic zebrafish lines expressing G93A-SOD1 to further characterize the consequences of G93A-SOD1 expression on neuromuscular pathology and disease progression. Behavioral monitoring reveals evidence of motor dysfunction and decreased activity in transgenic ALS zebrafish. Examination of neuromuscular and neuronal pathology throughout the disease course reveals a loss of neuromuscular junctions and alterations in motor neuron innervations patterns with disease progression. Finally, motor neuron cell loss is evident later in the disease. CONCLUSIONS: This sequence of events reflects the stepwise mechanisms of degeneration in ALS, and provides a novel model for mechanistic discovery and therapeutic development for neuromuscular degeneration in ALS.

A novel approach to study motor neurons from zebrafish embryos and larvae in culture.

Zebrafish are becoming increasingly popular models for examining the mechanisms of and treatments for neurological diseases. The available methods and technology to examine disease processes in vivo are increasing, however, detailed observations of subcellular structures and processes are complex in whole organisms. To address this need, we developed a primary motor neuron (MN) culture technique for utilization with zebrafish neurological disease models. Our protocol enables the culturing of cells from embryos older than 24h post-fertilization, at points after MN axonal development and outgrowth begins, which enables MN axons to develop in vivo in the context of the normal endogenous cues of the model organism, while also providing the accessibility of an in vitro system. When utilized with the increasing number of genetically modified or transgenic models of neurological diseases, this approach provides a novel tool for the examination of cellular and subcellular disease mechanisms, and offers a new platform for therapeutic discoveries in zebrafish.

Intraspinal transplantation of neurogenin-expressing stem cells generates spinal cord neural progenitors.

Embryonic stem (ES) cells and their derivatives are an important resource for developing novel cellular therapies for disease. Controlling proliferation and lineage selection, however, are essential to circumvent the possibility of tumor formation and facilitate the safe translation of ES-based therapies to man. Expression of appropriate transcription factors is one approach to direct the differentiation of ES cells towards a specific lineage and stop proliferation. Neural differentiation can be initiated in ES cells by expression of Neurogenin1 (Ngn1). In this study we investigate the effects of controlled Ngn1 expression on mouse ES (mES) cell differentiation in vitro and following grafting into the rat spinal cord. In vitro, Ngn1 expression in mES cells leads to rapid and specific neural differentiation, and a concurrent decrease in proliferation. Similarly transplantation of Ngn1-expressing mES cells into the spinal cord lead to in situ differentiation and spinal precursor formation. These data demonstrate that Ngn1 expression in mES cells is sufficient to promote neural differentiation and inhibit proliferation, thus establishing an approach to safely graft ES cells into the spinal cord.

Translational stem cell therapy for amyotrophic lateral sclerosis.

Effective treatments are urgently needed for amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease characterized by the loss of motor neurons. In 2009, the FDA approved the first phase I safety trial of direct intraspinal transplantation of neural stem cells into patients with ALS, which is currently in progress. Stem cell technologies represent a promising approach for treating ALS, but several issues must be addressed when translating promising experimental ALS therapies to patients. This article highlights the key research that supports the use of stem cells as a therapy for ALS, and discusses the rationale behind and approach to the phase I trial. Completion of the trial could pave the way for continued advances in stem cell therapy for ALS and other neurodegenerative diseases.

Stem cell technology for neurodegenerative diseases.

Over the past 20 years, stem cell technologies have become an increasingly attractive option to investigate and treat neurodegenerative diseases. In the current review, we discuss the process of extending basic stem cell research into translational therapies for patients suffering from neurodegenerative diseases. We begin with a discussion of the burden of these diseases on society, emphasizing the need for increased attention toward advancing stem cell therapies. We then explain the various types of stem cells utilized in neurodegenerative disease research, and outline important issues to consider in the transition of stem cell therapy from bench to bedside. Finally, we detail the current progress regarding the applications of stem cell therapies to specific neurodegenerative diseases, focusing on Parkinson disease, Huntington disease, Alzheimer disease, amyotrophic lateral sclerosis, and spinal muscular atrophy. With a greater understanding of the capacity of stem cell technologies, there is growing public hope that stem cell therapies will continue to progress into realistic and efficacious treatments for neurodegenerative diseases.

Optimization of immunosuppressive therapy for spinal grafting of human spinal stem cells in a rat model of ALS.

Previous rodent studies employing monotherapy or combined immunosuppressive regimens have demonstrated a variable degree of spinal xenograft survival in several spinal neurodegenerative models including spinal ischemia, trauma, or amyotrophic lateral sclerosis (ALS). Accordingly, the characterization of optimal immunosuppressive protocols for the specific neurodegenerative model is critical to ensure reliable assessment of potential long-term therapeutic effects associated with cell replacement. In the present study we characterized the survival of human spinal stem cells when grafted into the lumbar spinal cords of a rodent model of ALS, SOD1 (G93A) male and female rats (60-67 days old). Four different immunosuppressive protocols were studied: i) FK506 (q12h); ii) FK506 (qd) + mycophenolate (PO; q12h, up to 7 days postop); iii) FK506 (qd) + mycophenolate (IP; q12h, up to 7 days postop); and iv) FK506 (qd) + mycophenolate (IP; qd, up to 7 days postop). Three weeks after cell grafting the number of surviving human cells was then systematically assessed. The highest density of grafted cells was seen in animals treated with FK506 (qd) and mycophenolate (IP; qd; an average 915 ± 95 grafted cells per spinal cord section). The majority of hNUMA-positive cells colocalized with doublecortin (DCX) immunoreactivity. DCX-positive neurons showed extensive axodendritic sprouting toward surrounding host neurons. In addition, migrating grafted cells were identified up to 500 µm from the graft. In animals treated with FK506 (q12h), FK506 (qd) + mycophenolate (PO; q12h) or FK506 (qd) + mycophenolate (IP; q12h), 11.8 ± 3.4%, 61.2 ± 7.8%, and 99.4 ± 8.9% [expressed as percent of the FK506 (qd) and mycophenolate (IP; qd)] cell survival was seen, respectively. In contrast to animals treated with a combination of FK506 + mycophenolate, robust CD4/8 immunoreactivity was identified in the vicinity of the injection tract in animals treated with FK506 only. These data suggest that a combined, systemically delivered immunosuppression regimen including FK506 and mycophenolate can significantly improve survival of human spinal stem cells after intraspinal transplantation in SOD1 (G93A) rats.

Stem cell technology for the study and treatment of motor neuron diseases.

Amyotrophic lateral sclerosis and spinal muscular atrophy are devastating neurodegenerative diseases that lead to the specific loss of motor neurons. Recently, stem cell technologies have been developed for the investigation and treatment of both diseases. Here we discuss the different stem cells currently being studied for mechanistic discovery and therapeutic development, including embryonic, adult and induced pluripotent stem cells. We also present supporting evidence for the utilization of stem cell technology in the treatment of amyotrophic lateral sclerosis and spinal muscular atrophy, and describe key issues that must be considered for the transition of stem cell therapies for motor neuron diseases from bench to bedside. Finally, we discuss the first-in-human Phase I trial currently underway examining the safety and feasibility of intraspinal stem cell injections in amyotrophic lateral sclerosis patients as a foundation for translating stem cell therapies for various neurological diseases.

The pleotrophic effects of insulin-like growth factor-I on human spinal cord neural progenitor cells.

Most stem cell therapies involve direct, intraparachymal placement of neural progenitor cells. These cells provide physical support to the endogenous neuronal population and may be engineered to provide in situ growth factor support. Insulin-like growth factor-I (IGF-I) has potent neurotrophic and neuroprotective properties and is expressed by human neural stem cells (hNSCs). IGF-I is implicated in multiple aspects of cell behavior, including proliferation, differentiation, and survival. Enhancing hNSC function through IGF-I overexpression may increase the benefits of stem cell therapy. As a first step to that goal, we examined the direct effects of IGF-I on hNSC behavior in vitro. We demonstrate that IGF-I treatment enhances both the number and length of hNSC neurites. This is correlated with a decrease in proliferation, suggesting that IGF-I promotes neurite outgrowth but not proliferation. While IGF-I activates both AKT and MAPK signaling in hNSCs, we demonstrate that IGF-I-mediated neurite outgrowth is dependent only on AKT signaling. Finally, we demonstrate that IGF-I is neuroprotective after glutamate exposure in a model of excitotoxic cell death.

Neuroprotection using gene therapy to induce vascular endothelial growth factor-A expression.

Engineered zinc-finger protein (ZFP) transcription factors induce the expression of endogenous genes and can be remotely delivered using adenoviral vectors. One such factor, Ad-32Ep65-Flag (Ad-p65), targets and induces expression of vascular endothelial growth factor (VEGF; also called VEGF-A) splice variants in their normal biological stoichiometry. We show that Ad-p65 transfection of primary motor neurons results in VEGF variant expression and a significant increase in axon outgrowth in these cells. Given the neuroprotective effects of VEGF and its ability to increase neurite outgrowth, we examined the efficacy of Ad-p65 to enhance motor neuron regeneration in vivo using rats that have undergone recurrent laryngeal nerve (RLN)-crush injury. Injection of Ad-p65 after RLN crush accelerated the return of vocal fold mobility and the percentage of nerve-endplate contacts in the thyroarytenoid muscle. Overall, adenoviral delivery of an engineered ZFP transcription factor inducing VEGF-A splice variant expression enhances nerve regeneration. ZFP transcription factor gene therapy to increase expression of the full complement of VEGF-A splice variants is a promising avenue for the treatment of nerve injury and neurodegeneration.

Vascular endothelial growth factor prevents G93A-SOD1-induced motor neuron degeneration.

Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disorder characterized by selective loss of motor neurons (MNs). Twenty percent of familial ALS cases are associated with mutations in Cu(2+)/Zn(2+) superoxide dismutase (SOD1). To specifically understand the cellular mechanisms underlying mutant SOD1 toxicity, we have established an in vitro model of ALS using rat primary MN cultures transfected with an adenoviral vector encoding a mutant SOD1, G93A-SOD1. Transfected cells undergo axonal degeneration and alterations in biochemical responses characteristic of cell death such as activation of caspase-3. Vascular endothelial growth factor (VEGF) is an angiogenic and neuroprotective growth factor that can increase axonal outgrowth, block neuronal apoptosis, and promote neurogenesis. Decreased VEGF gene expression in mice results in a phenotype similar to that seen in patients with ALS, thus linking loss of VEGF to the pathogenesis of MN degeneration. Decreased neurotrophic signals prior to and during disease progression may increase MN susceptibility to mutant SOD1-induced toxicity. In this study, we demonstrate a decrease in VEGF and VEGFR2 levels in the spinal cord of G93A-SOD1 ALS mice. Furthermore, in isolated MN cultures, VEGF alleviates the effects of G93A-SOD1 toxicity and neuroprotection involves phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling. Overall, these studies validate the usefulness of VEGF as a potential therapeutic factor for the treatment of ALS and give valuable insight into the responsible signaling pathways and mechanisms involved.