Autism: a large unmet medical need and a complex research problem

Zebrafish models for translational neuroscience research: from tank to bedside

The zebrafish (Danio rerio) is emerging as a new important species for studying mechanisms of brain function and dysfunction. Focusing on selected central nervous system (CNS) disorders (brain cancer, epilepsy, and anxiety) and using them as examples, we discuss the value of zebrafish models in translational neuroscience. We further evaluate the contribution of zebrafish to neuroimaging, circuit level, and drug discovery research. Outlining the role of zebrafish in modeling a wide range of human brain disorders, we also summarize recent applications and existing challenges in this field. Finally, we emphasize the potential of zebrafish models in behavioral phenomics and high-throughput genetic/small molecule screening, which is critical for CNS drug discovery and identifying novel candidate genes.

Effect of camel milk on thymus and activation-regulated chemokine in autistic children: double-blind study

BACKGROUND

This study aimed to investigate the role of the effectiveness of camel milk (CM) (raw and boiled) on thymus and activation-regulated chemokine (TARC) serum levels and childhood autism rating scale (CARS) score in subjects with autism and compared to placebo group (cow milk).

METHODS

Forty-five subjects diagnosed with autism were randomly assigned to receive boiled CM for group I (n = 15), raw CM for group II (n = 15), and placebo for group III (n = 15) for 2 wk. Measures included changes in professionally completed CARS score and blood samples for TARC serum level were taken before and after milk consumption of 500 ml per day in children's regular daily diet.

RESULTS

The serum levels of TARC decreased significantly (P = 0.004) in boiled CM and in raw CM group (P = 0.01) too, but no effect was observed (P = 0.68) in placebo group. Furthermore, significant improvements were observed in CARS score (P = 0.04) in raw CM group only. There were no significant relationships between the serum of TARC level and the CARS score, age, or gender for any group.

CONCLUSION

CM administered for 2 wk significantly improved clinical measurements of autism severity and decreased serum level of TARC in autistic children, but subsequent studies are recommended.

Zebrafish as an emerging model for studying complex brain disorders

The zebrafish (Danio rerio) is rapidly becoming a popular model organism in pharmacogenetics and neuropharmacology. Both larval and adult zebrafish are currently used to increase our understanding of brain function, dysfunction, and their genetic and pharmacological modulation. Here we review the developing utility of zebrafish in the analysis of complex brain disorders (including, e.g., depression, autism, psychoses, drug abuse, and cognitive deficits), also covering zebrafish applications towards the goal of modeling major human neuropsychiatric and drug-induced syndromes. We argue that zebrafish models of complex brain disorders and drug-induced conditions are a rapidly emerging critical field in translational neuroscience and pharmacology research.

A prospective double-blind, randomized clinical trial of levocarnitine to treat autism spectrum disorders

Background

L-carnitine was proposed as a potential treatment for patients diagnosed with an autism spectrum disorder to improve mitochondrial dysfunction, but no prior randomized controlled trials have been conducted.

Material/Methods

Thirty subjects diagnosed with an ASD were randomly assigned to receive a standardized regimen (50 mg L-carnitine/kg bodyweight/day) of liquid L-carnitine (n=19) or placebo (n=11) for 3-months. Measures included changes in professionally completed Childhood Autism Rating Scale (CARS), hand muscle testing, and modified clinical global impression (CGI) forms; parent completed Autism Treatment Evaluation Checklist (ATEC), treatment adherence measurement (TAM), frequency and intensity of side effect rating (FISER)/global rating of side effect burden (GRSEB)/patient report of incidence of side effects (PRISE) forms; and lab testing.

Results

Significant improvements were observed in CARS (−2.03, 95% CI=−3.7 to −0.31), CGI (−0.69, 95% CI=−1.1 to −0.06), and ATEC scores. Significant correlations between changes in serum free-carnitine levels and positive clinical changes were observed for hand muscle strength (R²=0.23, P=0.046), cognitive scores (R²=0.27, P=0.019), and CARS scores (R²=0.20, P=0.047). Study subjects were protocol-compliant (average adherence was >85%) and generally well-tolerated the L-carnitine therapy given.

Conclusions

L-carnitine therapy (50 mg/kilogram-bodyweight/day) administered for 3-months significantly improved several clinical measurements of ASD severity, but subsequent studies are recommended.

Specialty Care Programme for Autism Spectrum Disorders in an Urban Population: A Case-Management Model for Health Care Delivery in an asd Population

Subjects with autism spectrum disorders (ASD) have more medical needs and more difficulties accessing health care services than the general population. Their verbal and non-verbal communication difficulties and particular behaviors, along with lack of expertise on the part of physicians and failure of the services to make adjustments, make it difficult for them to obtain an appropriate health care.

Purpose

To describe a model for health care delivery in an ASD population.

Method

Review of relevant literature and a discussion process with stakeholders leading to the design of a service to meet the specialty health needs of subjects of all ages with ASD for a region with a population of 6,000,000.

Results

A service was designed centred around the concepts of case management, individualization, facilitation, accompaniment, continuous training and updating, and quality management. Five hundred and thirteen patients with ASD have been seen over a period of 18 months. The programme generated 1566 psychiatric visits and 1052 visits to other specialties (mainly Nutrition, Stomatology, Neurology, and Gastroenterology) in the same period.

Conclusion

Persons with ASD may benefit from adjustments of health care services in order to improve their access to adequate health care at the quality level of the rest of the population.

Using zebrafish to unravel the genetics of complex brain disorders

The zebrafish has been prominently utilized in developmental biology for the past three decades and numerous genetic tools have been developed for it. Due to the accumulated genetic knowledge the zebrafish has now been considered an excellent research tool in other disciplines of biology too, including behavioral neuroscience and behavior genetics. Given the complexity of the vertebrate brain in general and the large number of human brain disorders whose mechanisms remain mainly unmapped in particular, there is a substantial need for appropriate laboratory research organisms that may be utilized to model such diseases and facilitate the analysis of their mechanisms. The zebrafish may have a bright future in this research field. It offers a compromise between system complexity (it is a vertebrate similar in many ways to our own species) and practical simplicity (it is small, easy to keep, and it is prolific). These features have made zebrafish an excellent choice, for example, for large scale mutation and drug screening. Such approaches may have a chance to tackle the potentially large number of molecular targets and mechanisms involved in complex brain disorders. However, although promising, the zebrafish is admittedly a novel research tool and only few empirical examples exist to support this claim. In this chapter, first I briefly review some of the rapidly evolving genetic methods available for zebrafish. Second, I discuss some promising examples for how zebrafish have been used to model and analyze molecular mechanisms of complex brain disorders. Last, I present some recently developed zebrafish behavioral paradigms that may have relevance for a spectrum of complex human brain disorders including those associated with abnormalities of learning and memory, fear and anxiety, and social behavior. Although at this point co-application of the genetics and behavioral approaches is rare with zebrafish, I argue that the rapid accumulation of knowledge in both of these disciplines will make zebrafish a prominent research tool for the genetic analysis of complex brain disorders.

Intersubjectivity, affective neuroscience, and the neurobiology of autistic spectrum disorders: a systematic review

Intersubjectivity is an approach to the study of social interaction viewed from a perspective which rejects the view that reducing any such analysis to study at the level of the individual is adequate to address the issues of social functioning. It also stresses the view that social processes cannot be reduced to cognitive ones - most of the important questions in the study of developmental psychopathology deal with issues which have commonality with many other species and are patent well before the ontological emergence of 'cognitive' abilities. In this paper we review the evidence in this area, and discuss a range of issues relevant to autistic spectrum disorders. We focus in particular on social interaction; the role of the Intrinsic Motive Formation and recent work on mirror neurons in autism; genetic and teratogenic factors in the genesis of autism; and the role of a number of biological factors in pathogenesis - tryptophan; vitamin B12; sterol metabolism; glutamate and GABA; and the Fragile-X expansion.

The social zebrafish: behavioral responses to conspecific, heterospecific, and computer animated fish

Zebrafish has been in the forefront of developmental biology and genetics, but only recently has interest in their behavior increased. Zebrafish are small and prolific, which lends this species to high throughput screening applications. A typical feature of zebrafish is its propensity to aggregate in groups, a behavior known as shoaling. Thus, zebrafish has been proposed as a possible model organism appropriate for the analysis of the genetics of vertebrate social behavior. However, shoaling behavior is not well characterized in zebrafish. Here, using a recently developed software application, we first investigate how zebrafish respond to conspecific and heterospecific fish species that differ in coloration and/or shoaling tendencies. We found that zebrafish shoaled with their own species but not with two heterospecific species, one of which was a shoaling the other a non-shoaling species. In addition, we have started the analysis of visual stimuli that zebrafish may utilize to determine whether to shoal with a fish or not. We systematically modified the color, the location, the pattern, and the body shape of computer animated zebrafish images and presented them to experimental zebrafish. The subjects responded differentially to some of these stimuli showing preference for yellow and avoidance of elongated zebrafish images. Our results suggest that computerized stimulus presentation and automated behavioral quantification of zebrafish responses are feasible, which in turn implies that high throughput forward genetic mutation or drug screening will be possible in the analysis of social behavior with this model organism.

Update on the National Vaccine Injury Compensation Program

The National Childhood Vaccine Injury Act of 1986, as amended, established the Vaccine Injury Compensation Program (VICP). The VICP went into effect on October 1, 1988 and is a Federal "no-fault" system designed to compensate individuals, or families of individuals, who have been injured by covered vaccines. From 1988 until July 2006, a total of 2531 non-autism/thimerosal and 5030 autism/thimerosal claims were made to the VICP. The compensation paid for the non-autism/thimerosal claims from 1988 until 2006 was $902,519,103.37 for 2542 awards. There was no compensation for any of the autism/thimerosal claims. On the basis of the deaths and extensive suffering to patients and families from the adverse reactions to vaccines, all physicians must provide detailed information in the Vaccine Information Statement to the patient or the parent or legal guardian of the child about the potential dangers of vaccines as well as the VICP.

Medicaid expenditures for children with autistic spectrum disorders: 1994 to 1999

This study used data from 1994 to 1999 from one large county in Pennsylvania to estimate the Medicaid expenditures of children diagnosed with autism spectrum disorders (ASD) and to compare these expenditures with those of other Medicaid-eligible children. On average, children diagnosed with ASD had expenditures 10 times those of other children. Differences in expenditures were driven in large part by inpatient psychiatric care. Further research is required to determine whether hospitalized children could be served in less restrictive and less expensive settings. Lack of differences in ambulatory care expenditures suggests that children with ASD are not receiving additional primary care services that would be indicative of appropriately coordinated services as suggested by the medical home model.

Assessing autism-like behavior in mice: variations in social interactions among inbred strains

Autism is a pervasive developmental disorder, with characteristics including impairments in reciprocal social interaction, impaired communication, and repetitive/stereotyped behaviors. Despite decades of research, the etiology of autism remains elusive. Thus, it is important that we pursue all avenues, in attempting to understand this complicated disorder. One such avenue is the development of animal models. While autism may be uniquely human, there are behavioral characteristics of the disorder that can be established in animal models. Evidence supports a genetic component for this disorder, and over the past few decades the mouse has been a highly valuable tool for the elucidation of pathways involved in many human disorders (e.g., Huntington's disease). As a first step toward establishing a mouse model of autism, we studied same-sex social behavior in a number of inbred mouse strains. In Study 1, we examined intra-strain social behavior of male pairs after one mouse had 15 min prior exposure to the testing chamber. In Study 2, we evaluated intra-strain and inter-strain social behavior when both mice were naive to the testing chamber. The amount and type of social behavior seen differed between these studies, but overall there were general inbred strain differences in social behavior. Some strains were highly social, e.g., FVB/NJ, while others displayed low levels of social behavior (e.g., A/J, BTBR T+tf/J). These strains may be useful in future genetic studies to determine specific genes involved in mouse social behavior, the findings of which should in turn help us to determine some of the genes involved in human social behavior and its disorders (e.g., autism).

The neuropathology, medical management and dental implications of autism

BACKGROUND

A paucity of information exists in the dental literature about autism and its dental implications.

TYPES OF STUDIES REVIEWED

The authors conducted a MEDLINE search for the period 2000 through 2006, using the term "autism," with the aim of defining the condition's clinical manifestations, dental and medical treatment and dental implications.

RESULTS

Autism is a severe developmental brain disorder that appears in infancy, persists throughout life, and is characterized by impaired social interaction, abnormalities in communication (both verbal and nonverbal) and restricted interests. Often accompanying the disorder are behavioral disturbances - such as self-mutilation, aggression, psychiatric symptoms and seizures - that necessitate the administration of multiple medications to help the affected person participate effectively in the educational and rehabilitative process.

CLINICAL IMPLICATIONS

Dentists caring for people with autism must be familiar with the manifestations of the disease and its associated features so that they can garner the maximum level of patient cooperation. They also must be familiar with the medications used to treat the associated features of the disorder because many of them cause untoward orofacial and systemic reactions and may precipitate adverse interactions with dental therapeutic agents.

An evaluation of the effects of thimerosal on neurodevelopmental disorders reported following DTP and Hib vaccines in comparison to DTPH vaccine in the United States

Thimerosal is an ethylmercury (49.55% mercury by weight) preservative historically added to some vaccines. Toxicokinetic studies showed children in the United States received doses of mercury from Thimerosal-containing vaccines (TCVs) in excess of safety guidelines. In the United States during the 1990s, diphtheria-tetanus-pertussis (DTP) and Haemophilus influenzae type b (Hib) vaccines (maximally, 50 mug mercury per joint administration) and diphtheria-tetanus-pertussis-Haemophilus influenzae type b (DTPH) vaccines (25 mug mercury per administration) were given to children in the same childhood vaccination schedule at 2, 4, 6, and 15-18 mo, so that children receiving DTP and Hib vaccines may have maximally received an additional 100 mug more mercury exposure from TCVs than children administered DTPH vaccines. A case-control epidemiological study of neurodevelopmental disorders (NDs) reported to the Vaccine Adverse Event Reporting System (VAERS) (online public access version; updated 31 August 2004) following administration of DTP vaccines in comparison DTPH vaccines manufactured by Lederle Laboratories (Pearl River, NY) from 1994 through 1998 was undertaken. Significantly increased odds ratios for autism, speech disorders, mental retardation, infantile spasms, and thinking abnormalities reported to VAERS were found following DTP vaccines in comparison to DTPH vaccines with minimal bias or systematic error. Additional ND research should be undertaken in the context of evaluating mercury-associated exposures, especially since in 2005 the Institute of Medicine issued a report calling into question handling of vaccine safety data by the National Immunization Program of the Centers for Disease Control and Prevention.

Autism: a target of pharmacotherapies?

Autism is reaching epidemic proportions. The diagnosis can be made as early as 2 years of age, and autistic patients are expected to have a normal life span. Thus, in terms of the number of 'patient years', autism spectrum disorder (ASD) represents a market that is as large as that of the biggest neurological indication, Alzheimer's disease. However, despite the clear unmet medical need no effective treatment is yet available. This could be because the biology of ASD is not clearly understood and thus proper drug treatment has not been possible. However, significant advances are being made toward understanding the mechanisms of the disease. Here, we review the most recent preclinical advances in the hope that they will lead to a breakthrough in the near future.