Towards large-cohort comparative studies to define the factors influencing the gut microbial community structure of ASD patients.

Differences in the gut microbiota have been reported between individuals with autism spectrum disorders (ASD) and neurotypical controls, although direct evidence that changes in the microbiome contribute to causing ASD has been scarce to date. Here we summarize some considerations of experimental design that can help untangle causality in this complex system. In particular, large cross-sectional studies that can factor out important variables such as diet, prospective longitudinal studies that remove some of the influence of interpersonal variation in the microbiome (which is generally high, especially in children), and studies transferring microbial communities into germ-free mice may be especially useful. Controlling for the effects of technical variables, which have complicated efforts to combine existing studies, is critical when biological effect sizes are small. Large citizen-science studies with thousands of participants such as the American Gut Project have been effective at uncovering subtle microbiome effects in self-collected samples and with self-reported diet and behavior data, and may provide a useful complement to other types of traditionally funded and conducted studies in the case of ASD, especially in the hypothesis generation phase

A murine model for neuropsychiatric disorders associated with group A β-hemolytic streptococcal infection

A syndrome of motoric and neuropsychiatric symptoms comprising various elements, including chorea, hyperactivity, tics, emotional lability, and obsessive-compulsive symptoms, can occur in association with group A β-hemolytic streptococcal (GABHS) infection. We tested the hypothesis that an immune response to GABHS can result in behavioral abnormalities. Female SJL/J mice were immunized and boosted with a GABHS homogenate in Freund's adjuvant, whereas controls received Freund's adjuvant alone. When sera from GABHS-immunized mice were tested for immunoreactivity to mouse brain, a subset was found to be immunoreactive to several brain regions, including deep cerebellar nuclei (DCN), globus pallidus, and thalamus. GABHS-immunized mice having serum immunoreactivity to DCN also had increased IgG deposits in DCN and exhibited increased rearing behavior in open-field and hole-board tests compared with controls and with GABHS-immunized mice lacking serum anti-DCN antibodies. Rearing and ambulatory behavior were correlated with IgG deposits in the DCN and with serum immunoreactivity to GABHS proteins in Western blot. In addition, serum from a GABHS mouse reacted with normal mouse cerebellum in nondenaturing Western blots and immunoprecipitated C4 complement protein and α-2-macroglobulin. These results are consistent with the hypothesis that immune response to GABHS can result in motoric and behavioral disturbances and suggest that anti-GABHS antibodies cross-reactive with brain components may play a role in their pathophysiology

Toll-like Receptor 3 Regulates Neural Stem Cell Proliferation by Modulating the Sonic Hedgehog Pathway

Toll-like receptor 3 (TLR3) signaling has been implicated in neural stem/precursor cell (NPC) proliferation. However, the molecular mechanisms involved, and their relationship to classical TLR-mediated innate immune pathways, remain unknown. Here, we report investigation of the mechanics of TLR3 signaling in neurospheres comprised of epidermal growth factor (EGF)-responsive NPC isolated from murine embryonic cerebral cortex of C57BL/6 (WT) or TLR3 deficient (TLR3−/−) mice. Our data indicate that the TLR3 ligand polyinosinic-polycytidylic acid (PIC) negatively regulates NPC proliferation by inhibiting Sonic Hedgehog (Shh) signaling, that PIC induces apoptosis in association with inhibition of Ras-ERK signaling and elevated expression of Fas, and that these effects are TLR3-dependent, suggesting convergent signaling between the Shh and TLR3 pathways

Nonparametric methods for the analysis of single-color pathogen microarrays

<p>Abstract</p> <p>Background</p> <p>The analysis of oligonucleotide microarray data in pathogen surveillance and discovery is a challenging task. Target template concentration, nucleic acid integrity, and host nucleic acid composition can each have a profound effect on signal distribution. Exploratory analysis of fluorescent signal distribution in clinical samples has revealed deviations from normality, suggesting that distribution-free approaches should be applied.</p> <p>Results</p> <p>Positive predictive value and false positive rates were examined to assess the utility of three well-established nonparametric methods for the analysis of viral array hybridization data: (1) Mann-Whitney <it>U</it>, (2) the Spearman correlation coefficient and (3) the chi-square test. Of the three tests, the chi-square proved most useful.</p> <p>Conclusions</p> <p>The acceptance of microarray use for routine clinical diagnostics will require that the technology be accompanied by simple yet reliable analytic methods. We report that our implementation of the chi-square test yielded a combination of low false positive rates and a high degree of predictive accuracy.</p

A staged strategy for pathogen surveillance and discovery

Recent advances in molecular diagnostics have revolutionized microbiology by facilitating rapid, sensitive pathogen surveillance and differential diagnosis of infectious diseases. Implementation of these technologies can enable intervention when the prognosis is optimal for limiting replication, dissemination, transmission, morbidity and mortality. It may also reveal unappreciated links between infection and chronic diseases. Although new pathogens continue to emerge, we have likely collected much of the "low hanging fruit" (microbes readily associated with diseases). An important task now is to understand those disorders that reflect the interaction of microbes with other environmental factors (toxins, other stressors) and susceptibility genes in a developmental context. Here I will review the strengths and limitations of various assay platforms, describe the challenges associated with proving causation, and delineate a staged strategy for pathogen discovery focused in emerging infectious disease "hot spots," "hot hosts," and prospective birth cohorts

Risk of attention-deficit hyperactivity disorder in offspring of mothers with infections during pregnancy

Background Maternal infections during pregnancy are common events that have been suggested to be risk factors for Attention-deficit hyperactivity disorder (ADHD) in offspring. Only a few studies have been conducted to date and results are conflicting. The current study investigates the associations between specific groups of prenatal maternal infections and offspring ADHD, considering timing of exposure and the role of fever. Methods We used data from the prospective Norwegian Mother, Father and Child Cohort Study (MoBa), including more than 112,000 pregnancies, linked with data from the Medical Birth Registry of Norway and the Norwegian Patient Registry to estimate odds ratios for the likelihood that children develop ADHD after being exposed to maternal infections during gestation. Results Children exposed to any maternal infection during pregnancy showed increased risk of receiving an ADHD diagnosis (OR = 1.15, CI = 1.03–1.27). Specifically, increased ADHD risk was observed after exposure to genitourinary infections in second (OR = 1.42, CI = 1.06–1.90) or third trimester (OR = 2.04, CI = 1.19–3.49), and to respiratory infections in second trimester (OR = 1.31, CI = 1.12–1.54), provided these infections were accompanied by episodes of fever. Increased ADHD risk was also observed after exposure to diarrhea without fever in the third trimester (OR = 1.25, CI = 1.07–1.46). Conclusions Overall, our results suggest that prenatal exposure to maternal infections, particularly with co-occurring episodes of fever, are risk factors for ADHD. Fever (or severity of the infection) appears to be more important in mid-pregnancy associations. Our results indicate that type of infection and timing of exposure might influence the associations, but small effect sizes require careful interpretations. The association between infection and ADHD should be estimated using discordant siblings or other negative control designs that give better adjustment for unmeasured familial confounding.publishedVersio

Streptococcus Pneumoniae coinfection is correlated with the severity of H1N1 pandemic Influenza

Fil: Palacios, Gustavo. Columbia University. Center for Infection and Immunity; Estados Unidos.Fil: Hornig, Mady. Columbia University. Center for Infection and Immunity; Estados Unidos.Fil: Cisterna, Daniel. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Savji, Nazir. Columbia University. Center for Infection and Immunity; Estados Unidos.Fil: Bussetti, Ana Valeria. Columbia University. Center for Infection and Immunity; Estados Unidos.Fil: Kapoor, Vishal. Columbia University. Center for Infection and Immunity; Estados Unidos.Fil: Hui, Jeffrey. Columbia University. Center for Infection and Immunity; Estados Unidos.Fil: Tokarz, Rafal. Columbia University. Center for Infection and Immunity; Estados Unidos.Fil: Briese, Thomas. Columbia University. Center for Infection and Immunity; Estados Unidos.Fil: Baumeister, Elsa. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Lipkin, W. Ian. Columbia University. Center for Infection and Immunity; Estados Unidos.Background Initial reports in May 2009 of the novel influenza strain H1N1pdm estimated a case fatality rate (CFR) of 0.6%, similar to that of seasonal influenza. In July 2009, however, Argentina reported 3056 cases with 137 deaths, representing a CFR of 4.5%. Potential explanations for increased CFR included virus reassortment or genetic drift, or infection of a more vulnerable population. Virus genomic sequencing of 26 Argentinian samples representing both severe and mild disease indicated no evidence of reassortment, mutations associated with resistance to antiviral drugs, or genetic drift that might contribute to virulence. Furthermore, no evidence was found for increased frequency of risk factors for H1N1pdm disease. Methods/Principal Findings We examined nasopharyngeal swab samples (NPS) from 199 cases of H1N1pdm infection from Argentina with MassTag PCR, testing for 33 additional microbial agents. The study population consisted of 199 H1N1pdm-infected subjects sampled between 23 June and 4 July 2009. Thirty-nine had severe disease defined as death (n = 20) or hospitalization (n = 19); 160 had mild disease. At least one additional agent of potential pathogenic importance was identified in 152 samples (76%), including Streptococcus pneumoniae (n = 62); Haemophilus influenzae (n = 104); human respiratory syncytial virus A (n = 11) and B (n = 1); human rhinovirus A (n = 1) and B (n = 4); human coronaviruses 229E (n = 1) and OC43 (n = 2); Klebsiella pneumoniae (n = 2); Acinetobacter baumannii (n = 2); Serratia marcescens (n = 1); and Staphylococcus aureus (n = 35) and methicillin-resistant S. aureus (MRSA, n = 6). The presence of S. pneumoniae was strongly correlated with severe disease. S. pneumoniae was present in 56.4% of severe cases versus 25% of mild cases; more than one-third of H1N1pdm NPS with S. pneumoniae were from subjects with severe disease (22 of 62 S. pneumoniae-positive NPS, p = 0.0004). In subjects 6 to 55 years of age, the adjusted odds ratio (OR) of severe disease in the presence of S. pneumoniae was 125.5 (95% confidence interval [CI], 16.95, 928.72; p<0.0001). Conclusions/Significance The association of S. pneumoniae with morbidity and mortality is established in the current and previous influenza pandemics. However, this study is the first to demonstrate the prognostic significance of non-invasive antemortem diagnosis of S. pneumoniae infection and may provide insights into clinical management

Apgar score and risk of autism

Low Apgar score has been associated with higher risk for several neurological and psychiatric disorders, including cerebral palsy and intellectual disability. Studies of the association between Apgar score and autism spectrum disorder (ASD) have been inconsistent. We aimed to investigate (1) the association between low Apgar score at 5 min and risk for ASD, and (2) the modifying effects of gestational age and sex on this association in the largest multinational database of ASD. We included prospective data from 5.5 million individuals and over 33,000 cases of ASD from Norway, Sweden, Denmark and Western Australia who were born between 1984 and 2007. We calculated crude and adjusted risk ratios (RR) with 95% confidence intervals (95% CIs) for the associations between low Apgar score and ASD. All analyses for ASD were repeated for autistic disorder (AD). We used interaction terms and stratified analysis to investigate the effects of sex, gestational age, and birth weight on the association. In fully adjusted models, low Apgar scores (1–3) (RR, 1.42; 95% CI, 1.16–1.74), and intermediate Apgar scores (4–6) (RR, 1.50; 95% CI, 1.36–1.65) were associated with a higher RR of ASD than optimal Apgar score (7–10). The point estimates for low (RR, 1.88; 95% CI, 1.41–2.51) and intermediate Apgar score (RR, 1.54; 95% CI, 1.32–1.81) were larger for AD than for ASD. This study suggests that low Apgar score is associated with higher risk of ASD, and in particular AD. We did not observe any major modifying effects of gestational age and sex, although there seems to be substantial confounding by gestational age and birth weight on the observed association.</p

Novel Borna Virus in Psittacine Birds with Proventricular Dilatation Disease

Pyrosequencing of cDNA from brains of parrots with proventricular dilatation disease (PDD), an unexplained fatal inflammatory central, autonomic, and peripheral nervous system disease, showed 2 strains of a novel Borna virus. Real-time PCR confirmed virus presence in brain, proventriculus, and adrenal gland of 3 birds with PDD but not in 4 unaffected birds