13 research outputs found
Structural brain abnormalities in 12 persons with aniridia [version 2; referees: 2 approved]
Background: Aniridia is a disorder predominately caused by heterozygous loss-of-function mutations of the PAX6 gene, which is a transcriptional regulator necessary for normal eye and brain development.  The ocular abnormalities of aniridia have been well characterized, but mounting evidence has implicated brain-related phenotypes as a prominent feature of this disorder as well. Investigations using neuroimaging in aniridia patients have shown reductions in discrete brain structures and changes in global grey and white matter. However, limited sample sizes and substantive heterogeneity of structural phenotypes in the brain remain a challenge. Methods: Here, we examined brain structure in a new population sample in an effort to add to the collective understanding of anatomical abnormalities in aniridia. The current study used 3T magnetic resonance imaging to acquire high-resolution structural data in 12 persons with aniridia and 12 healthy demographically matched comparison subjects. Results: We examined five major structures: the anterior commissure, the posterior commissure, the pineal gland, the corpus callosum, and the optic chiasm. The most consistent reductions were found in the anterior commissure and the pineal gland; however, abnormalities in all of the other structures examined were present in at least one individual. Conclusions: Our results indicate that the anatomical abnormalities in aniridia are variable and largely individual-specific. These findings suggest that future studies investigate this heterogeneity further, and that normal population variation should be considered when evaluating structural abnormalities
Increased functional connectivity in intrinsic neural networks in individuals with aniridia
Mutations affecting the PAX6 gene result in aniridia, a condition characterized by the lack of an iris and other panocular defects. Among humans with aniridia, structural abnormalities also have been reported within the brain. The current study examined the functional implications of these deficits through resting state or task-free functional magnetic resonance imaging in 12 individuals with aniridia and 12 healthy age- and gender-matched controls. Using independent components analysis and dual regression, individual patterns of functional connectivity associated with three intrinsic connectivity networks (executive control, primary visual, and default mode) were compared across groups. In all three analyses, the aniridia group exhibited regions of greater connectivity correlated with the network, while the controls did not show any such regions. These differences suggest that individuals with aniridia recruit additional neural regions to supplement function in critical intrinsic networks, possibly due to inherent structural or sensory abnormalities related to the disorder
Colonization of the live biotherapeutic product VE303 and modulation of the microbiota and metabolites in healthy volunteers
Manipulation of the gut microbiota via fecal microbiota transplantation (FMT) has shown clinical promise in diseases such as recurrent Clostridioides difficile infection (rCDI). However, the variable nature of this approach makes it challenging to describe the relationship between fecal strain colonization, corresponding microbiota changes, and clinical efficacy. Live biotherapeutic products (LBPs) consisting of defined consortia of clonal bacterial isolates have been proposed as an alternative therapeutic class because of their promising preclinical results and safety profile. We describe VE303, an LBP comprising 8 commensal Clostridia strains under development for rCDI, and its early clinical development in healthy volunteers (HVs). In a phase 1a/b study in HVs, VE303 is determined to be safe and well-tolerated at all doses tested. VE303 strains optimally colonize HVs if dosed over multiple days after vancomycin pretreatment. VE303 promotes the establishment of a microbiota community known to provide colonization resistance