Genomic and epigenetic evidence for oxytocin receptor deficiency in autism

<p>Abstract</p> <p>Background</p> <p>Autism comprises a spectrum of behavioral and cognitive disturbances of childhood development and is known to be highly heritable. Although numerous approaches have been used to identify genes implicated in the development of autism, less than 10% of autism cases have been attributed to single gene disorders.</p> <p>Methods</p> <p>We describe the use of high-resolution genome-wide tilepath microarrays and comparative genomic hybridization to identify copy number variants within 119 probands from multiplex autism families. We next carried out DNA methylation analysis by bisulfite sequencing in a proband and his family, expanding this analysis to methylation analysis of peripheral blood and temporal cortex DNA of autism cases and matched controls from independent datasets. We also assessed oxytocin receptor (OXTR) gene expression within the temporal cortex tissue by quantitative real-time polymerase chain reaction (PCR).</p> <p>Results</p> <p>Our analysis revealed a genomic deletion containing the oxytocin receptor gene, <it>OXTR </it>(MIM accession no.: 167055), previously implicated in autism, was present in an autism proband and his mother who exhibits symptoms of obsessive-compulsive disorder. The proband's affected sibling did not harbor this deletion but instead may exhibit epigenetic misregulation of this gene through aberrant gene silencing by DNA methylation. Further DNA methylation analysis of the CpG island known to regulate <it>OXTR </it>expression identified several CpG dinucleotides that show independent statistically significant increases in the DNA methylation status in the peripheral blood cells and temporal cortex in independent datasets of individuals with autism as compared to control samples. Associated with the increase in methylation of these CpG dinucleotides is our finding that <it>OXTR </it>mRNA showed decreased expression in the temporal cortex tissue of autism cases matched for age and sex compared to controls.</p> <p>Conclusion</p> <p>Together, these data provide further evidence for the role of OXTR and the oxytocin signaling pathway in the etiology of autism and, for the first time, implicate the epigenetic regulation of <it>OXTR </it>in the development of the disorder.</p> <p>See the related commentary by Gurrieri and Neri: <url>http://www.biomedcentral.com/1741-7015/7/63</url></p

Prospects for the development of probiotics and prebiotics for oral applications

There has been a paradigm shift towards an ecological and microbial community-based approach to understanding oral diseases. This has significant implications for approaches to therapy and has raised the possibility of developing novel strategies through manipulation of the resident oral microbiota and modulation of host immune responses. The increased popularity of using probiotic bacteria and/or prebiotic supplements to improve gastrointestinal health has prompted interest in the utility of this approach for oral applications. Evidence now suggests that probiotics may function not only by direct inhibition of, or enhanced competition with, pathogenic micro-organisms, but also by more subtle mechanisms including modulation of the mucosal immune system. Similarly, prebiotics could promote the growth of beneficial micro-organisms that comprise part of the resident microbiota. The evidence for the use of pro or prebiotics for the prevention of caries or periodontal diseases is reviewed, and issues that could arise from their use, as well as questions that still need to be answered, are raised. A complete understanding of the broad ecological changes induced in the mouth by probiotics or prebiotics will be essential to assess their long-term consequences for oral health and disease

The adrenal sensitivity to ACTH stimulation is preserved in anorexia nervosa

Hyperactivity of hypothalamus-pituitary-adrenal (HPA) axis in anorexia nervosa (AN) has been demonstrated and is likely to reflect a central nervous system (CNS)-mediated effect of starvation. Alterations in the adrenal response to ACTH in AN have also been reported by some authors. In order to define the adrenal sensitivity to ACTH in this condition, we studied cortisol (F), aldosterone (A) and DHEA responses to the sequential administration of low and supramaximal ACTH 1-24 doses (0.06 microg/m2 ACTH 1-24 iv at 0 min and 250 microg ACTH 1-24 iv at +60 min, respectively) in 10 young women with AN [ANW, age 21.2 +/- 0.9 yr, body mass index (BMI) 15.7 +/- 0.6 kg/m2]. The results in this group were compared with those recorded in 10 healthy normal women (HW, 23.4 +/- 1.1 yr, 21.9 +/- 0.9 kg/m2). In ANW urinary F levels were similar to those in HW. Basal serum F, A and DHEA levels in ANW were not significantly different from those in HW. In HW the lowest ACTH dose induced a significant (p&lt;0.05) increase of F, A and DHEA. The maximal ACTH dose induced F, A and DHEA increases greater (p&lt;0.05) than those induced by the lowest ACTH dose. In ANW both ACTH doses induced significant (p&lt;0.05) F and DHEA increases which were not significantly different from those in HW, though a trend toward a lower cortisol response after ACTH 0.06 microg/m2 in ANW was present. Like in HW, in ANW the maximal ACTH dose induced F and DHEA increases greater (p&lt;0.01) than those induced by the lowest dose. Unlike HW, in ANW A levels did not increase after the lowest ACTH dose while they increased after the maximal one overlapping the response in HW. In conclusion, the cortisol and DHEA responses to a very low and a supra-maximal ACTH dose in patients with AN were similar to those in healthy subjects, indicating that the sensitivity to ACTH of the fasciculata and reticularis adrenal zones is preserved in this condition. On the other hand, a reduced sensitivity to ACTH of the glomerularis adrenal zone in patients with AN is suggested by the lack of aldosterone response to the lowest corticotropin dose