A Twin Study of Altered White Matter Heritability in Youth With Autism Spectrum Disorder.

OBJECTIVE: White matter alterations are frequently reported in autism spectrum disorder (ASD), yet the etiology is currently unknown. The objective of this investigation was to examine, for the first time, the impact of genetic and environmental factors on white matter microstructure in twins with ASD compared to control twins without ASD. METHOD: Diffusion-weighted MRIs were obtained from same-sex twin pairs (6-15 years of age) in which at least 1 twin was diagnosed with ASD or neither twin exhibited a history of neurological or psychiatric disorders. Fractional anisotropy (FA) and mean diffusivity (MD) were examined across different white matter tracts in the brain, and statistical and twin modeling were completed to assess the proportion of variation associated with additive genetic (A) and common/shared (C) or unique (E) environmental factors. We also developed a novel Twin-Pair Difference Score analysis method that produces quantitative estimates of the genetic and environmental contributions to shared covariance between different brain and behavioral traits. RESULTS: Good-quality data were available from 84 twin pairs, 50 ASD pairs (32 concordant for ASD [16 monozygotic; 16 dizygotic], 16 discordant for ASD [3 monozygotic; 13 dizygotic], and 2 pairs in which 1 twin had ASD and the other exhibited some subthreshold symptoms [1 monozygotic; 1 dizygotic]) and 34 control pairs (20 monozygotic; 14 dizygotic). Average FA and MD across the brain, respectively, were primarily genetically mediated in both control twins (A = 0.80, 95% CI [0.57, 1.02]; A = 0.80 [0.55, 1.04]) and twins concordant for having ASD (A = 0.71 [0.33, 1.09]; A = 0.84 [0.32,1.36]). However, there were also significant tract-specific differences between groups. For instance, genetic effects on commissural fibers were primarily associated with differences in general cognitive abilities and perhaps some diagnostic differences for ASD because Twin-Pair Difference-Score analysis indicated that genetic factors may have contributed to ∼40% to 50% of the covariation between IQ scores and FA of the corpus callosum. Conversely, the increased impact of environmental factors on some projection and association fibers were primarily associated with differences in symptom severity in twins with ASD; for example, our analyses suggested that unique environmental factors may have contributed to ∼10% to 20% of the covariation between autism-related symptom severity and FA of the cerebellar peduncles and external capsule. CONCLUSION: White matter alterations in youth with ASD are associated with both genetic contributions and potentially increased vulnerability or responsivity to environmental influences. DIVERSITY & INCLUSION STATEMENT: We worked to ensure sex and gender balance in the recruitment of human participants. We worked to ensure race, ethnic, and/or other types of diversity in the recruitment of human participants. We worked to ensure that the study questionnaires were prepared in an inclusive way. One or more of the authors of this paper self-identifies as a member of one or more historically underrepresented racial and/or ethnic groups in science. One or more of the authors of this paper self-identifies as a member of one or more historically underrepresented sexual and/or gender groups in science. One or more of the authors of this paper self-identifies as living with a disability. The author list of this paper includes contributors from the location and/or community where the research was conducted and they participated in the data collection, design, analysis, and/or interpretation of the work.

Expanding the Library of Ions for Moisture-Swing Carbon Capture.

Developing materials that can more efficiently and cheaply capture carbon dioxide from ambient atmospheric conditions is essential for improving negative emission technologies. This study builds on the promising moisture-swing modality for direct air capture of carbon dioxide by investigating the use of several new anions─orthosilicate, borate, pyrophosphate, tripolyphosphate, and dibasic phosphate─that when introduced into ion-exchange resins allow for the cyclable capture of CO2 under dry conditions and its release under wet conditions. These ions, as well as many others that failed to show moisture-swing performance, are tested and directly compared thermodynamically and kinetically to understand their differences. This includes the use of analytical approaches new to the carbon capture field, such as the correlation of adsorption isotherms to moisture-swing performance, the use of phase lag kinetics, the examination of the humidity-carbon capture hysteresis of the sorbents, and the precise quantification of ion loading using inductively coupled plasma-optical emission spectroscopy. Phosphate dibasic was found to have the largest mass-normalized CO2 moisture-swing capacity, whereas phosphate tribasic had the best performance when factoring in kinetics, and pyrophosphate had the highest swing capacity when normalizing on a per-ion or per-unit-charge basis. This work not only sheds light on ways to improve DAC but also provides insights pertinent to the advancement of gas separation, negative emission technologies, and sorbent materials.

Tailoring Interactions of Random Copolymer Polyelectrolyte Complexes to Remove Nanoplastic Contaminants from Water.

We investigate the usage of polyelectrolyte complex materials for water remediation purposes, specifically their ability to remove nanoplastics from water, on which there is currently little to no prior research. We demonstrate that oppositely charged random copolymers are effective at quantitatively removing nanoplastic contamination from aqueous solution. The mechanisms underlying this remediation ability are explored through computational simulations, with corroborating quartz crystal microbalance adsorption experiments. We find that hydrophobic nanostructures and interactions likely play an important role.

Functional recovery and muscle atrophy in pre-clinical models of peripheral nerve transection and gap-grafting in mice: effects of 4-aminopyridine.

We recently demonstrated a repurposing beneficial effect of 4-aminopyridine (4-AP), a potassium channel blocker, on functional recovery and muscle atrophy after sciatic nerve crush injury in rodents. However, this effect of 4-AP is unknown in nerve transection, gap, and grafting models. To evaluate and compare the functional recovery, nerve morphology, and muscle atrophy, we used a novel stepwise nerve transection with gluing (STG), as well as 7-mm irreparable nerve gap (G-7/0) and 7-mm isografting in 5-mm gap (G-5/7) models in the absence and presence of 4-AP treatment. Following surgery, sciatic functional index was determined weekly to evaluate the direct in vivo global motor functional recovery. After 12 weeks, nerves were processed for whole-mount immunofluorescence imaging, and tibialis anterior muscles were harvested for wet weight and quantitative histomorphological analyses for muscle fiber cross-sectional area and minimal Feret's diameter. Average post-injury sciatic functional index values in STG and G-5/7 models were significantly greater than those in the G-7/0 model. 4-AP did not affect the sciatic functional index recovery in any model. Compared to STG, nerve imaging revealed more misdirected axons and distorted nerve architecture with isografting. While muscle weight, cross-sectional area, and minimal Feret's diameter were significantly smaller in G-7/0 model compared with STG and G-5/7, 4-AP treatment significantly increased right TA muscle mass, cross-sectional area, and minimal Feret's diameter in G-7/0 model. These findings demonstrate that functional recovery and muscle atrophy after peripheral nerve injury are directly related to the intervening nerve gap, and 4-AP exerts differential effects on functional recovery and muscle atrophy.

Erythropoietin-PLGA-PEG as a local treatment to promote functional recovery and neurovascular regeneration after peripheral nerve injury.

BACKGROUND: Traumatic peripheral nerve injury (TPNI) is a major medical problem with no universally accepted pharmacologic treatment. We hypothesized that encapsulation of pro-angiogenic erythropoietin (EPO) in amphiphilic PLGA-PEG block copolymers could serve as a local controlled-release drug delivery system to enhance neurovascular regeneration after nerve injury. METHODS: In this study, we synthesized an EPO-PLGA-PEG block copolymer formulation. We characterized its physiochemical and release properties and examined its effects on functional recovery, neural regeneration, and blood vessel formation after sciatic nerve crush injury in mice. RESULTS: EPO-PLGA-PEG underwent solution-to-gel transition within the physiologically relevant temperature window and released stable EPO for up to 18 days. EPO-PLGA-PEG significantly enhanced sciatic function index (SFI), grip strength, and withdrawal reflex post-sciatic nerve crush injury. Furthermore, EPO-PLGA-PEG significantly increased blood vessel density, number of junctions, and myelinated nerve fibers after injury. CONCLUSION: This study provides promising preclinical evidence for using EPO-PLGA-PEG as a local controlled-release treatment to enhance functional outcomes and neurovascular regeneration in TPNI.

Relationship Between MR Spectroscopy-Detected Glutamatergic Neurometabolites and Changes in Social Behaviors in a Pilot Open-Label Trial of Memantine for Adults With Autism Spectrum Disorder.

Background: The neurobiology underlying ASD is largely unknown but altered neural excitability/inhibitory ratios have been reported. Memantine is an N-methyl-D-aspartate (NMDA) glutamatergic antagonist studied for the treatment of core ASD symptoms, with mixed results. We examined whether glutamatergic levels were associated with and predicted response to memantine in an exploratory pilot study. Methods: Ten adult participants with ASD underwent proton magnetic resonance spectroscopy (1H-MRS) imaging at baseline and behavioral assessments before and after 12-weeks of open-label memantine. Post-treatment scores on Clinical Global Impressions-Improvement (CGI-I) for social interaction were the primary outcome measure, and scores on the Social Responsiveness Scale (SRS) were included as a secondary outcome. LCModel was used to quantify the concentrations of Point RESolved Spectroscopy-detected glutamate+glutamine (Glx) (and other neurometabolites, i.e., N-acetylaspartate, NAA; creatine+phosphocreatine, Cr+PCr, and myo-inositol, Ins), within the left dorsolateral prefrontal cortex (LDLPFC) and right (R) posterolateral cerebellum. SPM was used to perform brain tissue segmentation within the spectroscopic voxels. CGI-I scores post-treatment were used to classify the participants into two groups, responders (scores 1-3; n = 5) and non-responders (scores 4-7, or withdrew due to increase behaviors; n = 5). Independent samples t-tests, partial correlations and linear hierarchical regression models (SPSS) were used to determine between-group differences in neurometabolite concentrations and associations between neurometabolites and behavioral scores. Results: Responders and non-responders did not significantly differ in Glx levels in any region of interest, but differed in NAA levels in LDLPFC (higher in responders vs. non-responders). Although changes in CGI-I social scores were not correlated with Glx in any region of interest, the linear hierarchical regression did reveal that Glx and Ins levels in LDLPFC were predictors of post-treatment CGI-I social scores. Changes in SRS scores were correlated with baseline Cr+PCr levels in the LDLPFC. Discussion: Our pilot data suggest that baseline Glx, a marker of glutamatergic neurotransmission, did not directly predict response to memantine for social outcomes in adults with ASD. However, interactions between Glx and the neurometabolite associated with glial integrity (Ins) may help predict treatment response. Further, those with highest baseline NAA, a putative neuronal marker, and Cr+pCr, a brain energy metabolism marker, were the best responders. These preliminary results may explain some of the mixed results reported in previous memantine trials in ASD. Future studies will need to examine these results in a larger sample.

Altered gut microbiota composition with antibiotic treatment impairs functional recovery after traumatic peripheral nerve crush injury in mice: effects of probiotics with butyrate producing bacteria.

OBJECTIVE: Antibiotics (ABX) are widely used for life-threatening infections and also for routine surgical operations. Compelling evidence suggests that ABX-induced alterations of gut microbiota composition, termed dysbiosis, are linked with diverse disease states including neurological and neurodegenerative conditions. To combat the consequences of dysbiosis, probiotics (PBX) are widely used. ABX-induced dysbiosis is reported to impair neurological function after spinal cord injury. Traumatic peripheral nerve injury (TPNI) results in profound neurologic impairment and permanent disability. It is unknown whether ABX treatment-induced dysbiosis has any impact on TPNI-induced functional recovery, and if so, what role medical-grade PBX could have on TPNI recovery. RESULTS: In this study, ABX-induced dysbiosis and PBX-induced microbiota enrichment models were used to explore the potential role of gut microbiome in TPNI. Stool analysis with 16S ribosomal RNA (rRNA) gene sequencing confirmed ABX-induced dysbiosis and revealed that ABX-induced changes could be partially restored by PBX administration with an abundance of butyrate producing bacteria. Pre-injury ABX significantly impaired, but pre-injury PBX significantly improved post-TPNI functional recovery. Importantly, post-injury PBX protected against pre-injury ABX-induced functional impairment. These findings demonstrate that reestablishment of gut microbiota composition with butyrate producing PBX during ABX-induced dysbiosis could be a useful adjuvant therapy for TPNI.

Frequency drift in MR spectroscopy at 3T.

PURPOSE: Heating of gradient coils and passive shim components is a common cause of instability in the B0 field, especially when gradient intensive sequences are used. The aim of the study was to set a benchmark for typical drift encountered during MR spectroscopy (MRS) to assess the need for real-time field-frequency locking on MRI scanners by comparing field drift data from a large number of sites. METHOD: A standardized protocol was developed for 80 participating sites using 99 3T MR scanners from 3 major vendors. Phantom water signals were acquired before and after an EPI sequence. The protocol consisted of: minimal preparatory imaging; a short pre-fMRI PRESS; a ten-minute fMRI acquisition; and a long post-fMRI PRESS acquisition. Both pre- and post-fMRI PRESS were non-water suppressed. Real-time frequency stabilization/adjustment was switched off when appropriate. Sixty scanners repeated the protocol for a second dataset. In addition, a three-hour post-fMRI MRS acquisition was performed at one site to observe change of gradient temperature and drift rate. Spectral analysis was performed using MATLAB. Frequency drift in pre-fMRI PRESS data were compared with the first 5:20 minutes and the full 30:00 minutes of data after fMRI. Median (interquartile range) drifts were measured and showed in violin plot. Paired t-tests were performed to compare frequency drift pre- and post-fMRI. A simulated in vivo spectrum was generated using FID-A to visualize the effect of the observed frequency drifts. The simulated spectrum was convolved with the frequency trace for the most extreme cases. Impacts of frequency drifts on NAA and GABA were also simulated as a function of linear drift. Data from the repeated protocol were compared with the corresponding first dataset using Pearson's and intraclass correlation coefficients (ICC). RESULTS: Of the data collected from 99 scanners, 4 were excluded due to various reasons. Thus, data from 95 scanners were ultimately analyzed. For the first 5:20 min (64 transients), median (interquartile range) drift was 0.44 (1.29) Hz before fMRI and 0.83 (1.29) Hz after. This increased to 3.15 (4.02) Hz for the full 30 min (360 transients) run. Average drift rates were 0.29 Hz/min before fMRI and 0.43 Hz/min after. Paired t-tests indicated that drift increased after fMRI, as expected (p < 0.05). Simulated spectra convolved with the frequency drift showed that the intensity of the NAA singlet was reduced by up to 26%, 44 % and 18% for GE, Philips and Siemens scanners after fMRI, respectively. ICCs indicated good agreement between datasets acquired on separate days. The single site long acquisition showed drift rate was reduced to 0.03 Hz/min approximately three hours after fMRI. DISCUSSION: This study analyzed frequency drift data from 95 3T MRI scanners. Median levels of drift were relatively low (5-min average under 1 Hz), but the most extreme cases suffered from higher levels of drift. The extent of drift varied across scanners which both linear and nonlinear drifts were observed.

(4-Aminopyridine)-PLGA-PEG as a Novel Thermosensitive and Locally Injectable Treatment for Acute Peripheral Nerve Injury.

Traumatic peripheral nerve injury (TPNI) represents a major medical problem that results in loss of motor and sensory function, and in severe cases, limb paralysis and amputation. To date, there are no effective treatments beyond surgery in selective cases. In repurposing studies, we found that daily systemic administration of the FDA-approved drug 4-aminopyridine (4-AP) enhanced functional recovery after acute peripheral nerve injury. This study was aimed at constructing a novel local delivery system of 4-AP using thermogelling polymers. We optimized a thermosensitive (4-AP)-poly(lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PLGA-PEG-PLGA) block copolymer formulation. (4-AP)-PLGA-PEG exhibited controlled release of 4-AP both in vitro and in vivo for approximately 3 weeks, with clinically relevant safe serum levels in animals. Rheological investigation showed that (4-AP)-PLGA-PEG underwent a solution to gel transition at 32 °C, a physiologically relevant temperature, allowing us to administer it to an injured limb while subsequently forming an in situ gel. A single local administration of (4-AP)-PLGA-PEG remarkably enhanced motor and sensory functional recovery on post-sciatic nerve crush injury days 1, 3, 7, 14, and 21. Moreover, immunohistochemical studies of injured nerves treated with (4-AP)-PLGA-PEG demonstrated an increased expression of neurofilament heavy chain (NF-H) and myelin protein zero (MPZ) proteins, two major markers of nerve regeneration. These findings demonstrate that (4-AP)-PLGA-PEG may be a promising long-acting local therapeutic agent in TPNI, for which no pharmacologic treatment exists.

Obligatory role of Schwann cell-specific erythropoietin receptors in erythropoietin-induced functional recovery and neurogenic muscle atrophy after nerve injury.

BACKGROUND: Erythropoietin (EPO) promotes myelination and functional recovery in rodent peripheral nerve injury (PNI). While EPO receptors (EpoR) are present in Schwann cells, the role of EpoR in PNI recovery is unknown because of the lack of EpoR antagonists or Schwann cell-specific EpoR knockout animals. METHODS: Using the Cre-loxP system, we developed a myelin protein zero (Mpz) promoter-driven knockout mouse model of Schwann cell EpoR (MpzCre-EpoRflox/flox , Mpz-EpoR-KO). Mpz-EpoR-KO and control mice were assigned to sciatic nerve crush injury followed by EPO treatment. RESULTS: EPO treatment significantly accelerated functional recovery in control mice in contrast to significantly reduced functional recovery in Mpz-EpoR-KO mice. Significant muscle atrophy was found in the injured hindlimb of EPO-treated Mpz-EpoR-KO mice but not in EPO-treated control mice. CONCLUSIONS: These preliminary findings provide direct evidence for an obligatory role of Schwann-cell specific EpoR for EPO-induced functional recovery and muscle atrophy following PNI.

An effective erythropoietin dose regimen protects against severe nerve injury-induced pathophysiological changes with improved neural gene expression and enhances functional recovery.

The functional recovery following non-severing peripheral nerve injury (PNI) is often incomplete. Erythropoietin (EPO) is a pleiotropic hormone and it has been shown to protect peripheral nerves following mild and even moderate severity injuries. However, the effectiveness of EPO in severe PNI is largely unknown. In this study, we sought to investigate the neuroprotective effect of a new dose regimen of EPO in severe sciatic nerve crush injury (SSCI). Adult male mice (8 animals/group) were randomly assigned to sham (normal saline, 0.1 ml/mouse), SSCI (normal saline, 0.1 ml/mouse) and SSCI with EPO (5000 IU/kg) groups. SSCI was performed using calibrated forceps for 30 sec. EPO or normal saline was administered intraperitoneally immediately after the SSCI and at post-injury day1 and 2. The functional recovery after injury was assessed by sciatic function index (SFI), von Frey Test (VFT), and grip strength test. Mice were euthanized on day 7 and 21 and nerves at injury/peri-injury site were processed for gene (quantitative real-time PCR) and protein (immunohistochemistry) expression analysis. EPO significantly improved SFI, VFT, and hind limb paw grip strength from post-injury day 7. EPO demonstrated significant regulatory effects on mRNA expression of inflammatory (IL-1ß and TNF-α), anti-inflammatory (IL-10), angiogenesis (VEGF and eNOS), and myelination (MBP) genes. The protein expression of IL-1ß, F4/80, CD31, NF-κB p65, NF-H, MPZ, and DHE (redox-sensitive probe) was also significantly modulated by EPO treatment. In conclusion, the new dose regimen of EPO augments sciatic nerve functional recovery by mitigating inflammatory, anti-inflammatory, oxidative stress, angiogenesis, and myelination components of SSCI.

Beta-adrenergic antagonism alters functional connectivity during associative processing in a preliminary study of individuals with and without autism.

Beta-adrenergic antagonism (e.g. propranolol) has been associated with cognitive/behavioral benefits following stress-induced impairments and for some cognitive/behavioral domains in individuals with autism spectrum disorder. In this preliminary investigation, we examined whether the benefits of propranolol are associated with functional properties in the brain. Adolescents/adults (mean age = 22.54 years) with (n = 13) and without autism spectrum disorder (n = 13) attended three sessions in which propranolol, nadolol (beta-adrenergic antagonist that does not cross the blood-brain barrier), or placebo was administered before a semantic fluency task during functional magnetic resonance imaging. Autonomic nervous system measures and functional connectivity between language/associative processing regions and within the fronto-parietal control, dorsal attention, and default mode networks were examined. Propranolol was associated with improved semantic fluency performance, which was correlated with the baseline resting heart rate. Propranolol also altered network efficiency of regions associated with semantic processing and in an exploratory analysis reduced functional differences in the fronto-parietal control network in individuals with autism spectrum disorder. Thus, the cognitive benefits from beta-adrenergic antagonism may be generally associated with improved information processing in the brain in domain-specific networks, but individuals with autism spectrum disorder may also benefit from additional improvements in domain-general networks. The benefits from propranolol may also be able to be predicted from baseline autonomic nervous system measures, which warrants further investigation.

Genetic and environmental influences on structural brain measures in twins with autism spectrum disorder.

Atypical growth patterns of the brain have been previously reported in autism spectrum disorder (ASD) but these alterations are heterogeneous across individuals, which may be associated with the variable effects of genetic and environmental influences on brain development. Monozygotic (MZ) and dizygotic (DZ) twin pairs with and without ASD (aged 6-15 years) were recruited to participate in this study. T1-weighted MRIs (n = 164) were processed with FreeSurfer to evaluate structural brain measures. Intra-class correlations were examined within twin pairs and compared across diagnostic groups. ACE modeling was also completed. Structural brain measures, including cerebral and cerebellar gray matter (GM) and white matter (WM) volume, surface area, and cortical thickness, were primarily influenced by genetic factors in TD twins; however, mean curvature appeared to be primarily influenced by environmental factors. Similarly, genetic factors accounted for the majority of variation in brain size in twins with ASD, potentially to a larger extent regarding curvature and subcortical GM; however, there were also more environmental contributions in twins with ASD on some structural brain measures, such that cortical thickness and cerebellar WM volume were primarily influenced by environmental factors. These findings indicate potential neurobiological outcomes of the genetic and environmental risk factors that have been previously associated with ASD and, although preliminary, may help account for some of the previously outlined neurobiological heterogeneity across affected individuals. This is especially relevant regarding the role of genetic and environmental factors in the development of ASD, in which certain brain structures may be more sensitive to specific influences.

Effects of stress on functional connectivity during problem solving.

AIM: Our purpose was to examine how stress affects functional connectivity (FC) in language processing regions of the brain during a verbal problem solving task associated with creativity. We additionally explored how gender and the presence of the stress-susceptible short allele of the serotonin transporter gene polymorphism influenced this effect. METHODS: Forty-five healthy participants (Mean age: 19.6 â€‹± â€‹1.6 years; 28 females) were recruited to be a part of this study and genotyped to determine the presence or absence of at least one copy of the short (S) allele of the serotonin transporter gene, which is associated with greater susceptibility to stress. The participants underwent functional magnetic resonance imaging in two separate sessions (stress and no stress control). One session utilized a modified version of the Montreal Imaging Stress Test (MIST) to induce stress while the other session consisted of a no stress control task. The MIST and control tasks were interleaved with task blocks during which the participants performed the compound remote associates task, a convergent task that engages divergent thinking, which is a critical component of creativity. We examined the relationship between stress effects on performance and effects on connectivity of language processing regions activated during this task. RESULTS: There was no main effect of stress on functional connectivity for individual ROI pairs. However, in the examination of whether stress effects on performance related to effects on connectivity, changes in middle temporal gyrus connectivity with stress correlated positively with changes in solution latency for individuals with the S allele, but anti-correlated for those with only the L allele. A trend towards a gene â€‹× â€‹stress interaction on solution latency was also observed. DISCUSSION: Results from the study suggest that genetic susceptibility to stress, such as the presence of the S allele, affects neural correlates of performance on tasks related to verbal problem solving, as indicated by connectivity of the middle temporal gyrus. Future work will need to determine whether connectivity of the middle temporal gyrus serves as a marker for the effect of stress susceptibility on cognition, extending into stress susceptible patient populations.

Effects of stress on functional connectivity during verbal processing.

Effects of stress on functional connectivity (FC) in specific language processing regions of the brain during verbal fluency tasks were explored. Roles of gender and serotonin transporter gene polymorphisms (5-HTTLPR), associated with stress susceptibility, were also examined to understand their effect. Forty-five healthy volunteers (Mean age: 19.6 ± 1.6 years; 28 females) participated. Functional magnetic resonance imaging was carried out while participants performed letter and category fluency tasks. These tasks were interposed with the Montreal Imaging Stress Test to induce stress or a no-stress control task. Buccal swabs collected were used to genotype for the presence of polymorphisms on the SLC6A4 gene known to contribute to atypical stress responses. Significant variations in strength of FC were noted between several ROIs, including left inferior frontal gyrus and left middle temporal gyrus. Overall, males showed regional increases in FC strength over long and short distances during task under stress. Additionally, variability in effects of stress on task performance was associated with effects of stress on FC. Results suggest that long distance FC may be strengthened to compensate for additional cognitive load of the stressor but that specific short distance functional connections may be strengthened in a gender specific manner. Additionally, FC may serve as a marker for effects of stress on performance. This is the first study exploring stress effects on language tasks with imaging markers. Future studies will need to explore stress susceptible populations and establish the role of FC as a marker, with implications for targeted therapeutic interventions.

Genetic and Environmental Influences on Lobar Brain Structures in Twins With Autism.

This investigation examined whether the variation of cerebral structure is associated with genetic or environmental factors in children with autism spectrum disorder (ASD) compared with typically developing (TD) controls. T1-weighted magnetic resonance imaging scans were obtained from twin pairs (aged 6-15 years) in which at least one twin was diagnosed with ASD or both were TD. Good quality data were available from 30 ASD, 18 discordant, and 34 TD pairs (n = 164). Structural measures (volume, cortical thickness, and surface area) were generated with FreeSurfer, and ACE modeling was completed. Lobar structures were primarily genetically mediated in TD twins (a2 = 0.60-0.89), except thickness of the temporal (a2 = 0.33 [0.04, 0.63]) and occipital lobes (c2 = 0.61 [0.45, 0.77]). Lobar structures were also predominantly genetically mediated in twins with ASD (a2 = 0.70-1.00); however, thickness of the frontal (c2 = 0.81 [0.71, 0.92]), temporal (c2 = 0.77 [0.60, 0.93]), and parietal lobes (c2 = 0.87 [0.77, 0.97]), and frontal gray matter (GM) volume (c2 = 0.79 [0.63, 0.95]), were associated with environmental factors. Conversely, occipital thickness (a2 = 0.93 [0.75, 1.11]) did not exhibit the environmental contributions that were found in controls. Differences in GM volume were associated with social communication impairments for the frontal (r = 0.52 [0.18, 0.75]), temporal (r = 0.61 [0.30, 0.80]), and parietal lobes (r = 0.53 [0.19, 0.76]). To our knowledge, this is the first investigation to suggest that environmental factors influence GM to a larger extent in children with ASD, especially in the frontal lobe.

A pilot investigation of neuroimaging predictors for the benefits from pivotal response treatment for children with autism.

Children with autism spectrum disorder (ASD) frequently exhibit language delays and functional communication deficits. Pivotal response treatment (PRT) is an effective intervention for targeting these skills; however, similar to other behavioral interventions, response to PRT is variable across individuals. Thus, objective markers capable of predicting treatment response are critically-needed to identify which children are most likely to benefit from this intervention. In this pilot study, we investigated whether structural neuroimaging measures from language regions in the brain are associated with response to PRT. Children with ASD (n = 18) who were receiving PRT to target their language deficits were assessed with MRI at baseline. T1-weighted images were segmented with FreeSurfer and morphometric measures of the primary language regions (inferior frontal (IFG) and superior temporal (STG) gyri) were evaluated. Children with ASD and language deficits did not exhibit the anticipated relationships between baseline structural measures of language regions and baseline language abilities, as assessed by the number of utterances displayed during a structured laboratory observation (SLO). Interestingly, the level of improvement on the SLO was correlated with baseline asymmetry of the IFG, and the size of the left STG at baseline was correlated with the level of improvement on standardized parental questionnaires. Although very preliminary, the observed associations between baseline structural properties of language regions and improvement in language abilities following PRT suggest that neuroimaging measures may be able to help identify which children are most likely to benefit from specific language treatments, which could help improve precision medicine for children with ASD.

Cerebro-Cerebellar Functional Connectivity is Associated with Cerebellar Excitation-Inhibition Balance in Autism Spectrum Disorder.

Atypical functional connectivity (FC) and an imbalance of excitation-to-inhibition (E/I) have been previously reported in cerebro-cerebellar circuits in autism spectrum disorder (ASD). The current investigation used resting state fMRI and proton magnetic resonance spectroscopy (1H-MRS) to examine the relationships between E/I (glutamate + glutamine/GABA) and FC of the dorsolateral prefrontal cortex and posterolateral cerebellar hemisphere from 14 adolescents/adults with ASD and 12 age/sex/IQ-matched controls. In this pilot sample, cerebro-cerebellar FC was positively associated with cerebellar E/I and listening comprehension abilities in individuals with ASD but not controls. Additionally, a subgroup of individuals with ASD and low FC (n = 5) exhibited reduced E/I and impaired listening comprehension. Thus, altered functional coherence of cerebro-cerebellar circuits in ASD may be related with a cerebellar E/I imbalance.

Cationic amphiphilic bolaamphiphile-based delivery of antisense oligonucleotides provides a potentially microbiome sparing treatment for C. difficile.

Conventional antibiotics for C. difficile infection (CDI) have mechanisms of action without organismal specificity, potentially perpetuating the dysbiosis contributing to CDI, making antisense approaches an attractive alternative. Here, three (APDE-8, CODE-9, and CYDE-21) novel cationic amphiphilic bolaamphiphiles (CABs) were synthesized and tested for their ability to form nano-sized vesicles or vesicle-like aggregates (CABVs), which were characterized based on their physiochemical properties, their antibacterial activities, and their toxicity toward colonocyte (Caco-2) cell cultures. The antibacterial activity of empty CABVs was tested against cultures of E. coli, B. fragilis, and E. faecalis, and against C. difficile by "loading" CABVs with 25-mer antisense oligonucleotides (ASO) targeting dnaE. Our results demonstrate that empty CABVs have minimal colonocyte toxicity until concentrations of 71 µM, with CODE-9 demonstrating the least toxicity. Empty CABVs had little effect on C. difficile growth in culture (MIC90 ≥ 160 µM). While APDE-8 and CODE-9 nanocomplexes demonstrated high MIC90 against C. difficile cultures (>300 µM), CYDE-21 nanocomplexes demonstrated MIC90 at CABV concentrations of 19 µM. Empty CABVs formed from APDE-8 and CODE-9 had virtually no effect on E. coli, B. fragilis, and E. faecalis across all tested concentrations, while empty CYDE-21 demonstrated MIC90 of >160 µM against E. coli and >40 µM against B. fragilisand E. faecalis. Empty CABVs have limited antibacterial activity and they can deliver an amount of ASO effective against C. difficile at CABV concentrations associated with limited colonocyte toxicity, while sparing other bacteria. With further refinement, antisense therapies for CDI may become a viable alternative to conventional antibiotic treatment.

Antibiotic Treatments for Clostridium difficile Infection Are Associated with Distinct Bacterial and Fungal Community Structures.

Clostridium difficile infection (CDI) is the most common nosocomial infection in the United States, being associated with high recurrence and persistence rates. Though the relationship between intestinal dysbiosis and CDI is well known, it is unclear whether different forms of dysbiosis may potentially affect the course of CDI. How this is further influenced by C. difficile-directed antibiotics is virtually uninvestigated. In this study, diarrheal stool samples were collected from 20 hospitalized patients, half of whom were confirmed to have CDI. Analyzing tissue ex vivo and in duplicate, CDI and non-CDI fecal samples (n = 176) were either not antibiotic treated or treated with metronidazole, vancomycin, or fidaxomicin, the three most common CDI therapies. The microbial community composition, interactions, and predicted metabolic functions were assessed by 16S rRNA gene and internal transcribed spacer sequencing, bipartite network analysis, and phylogenetic investigation of communities by reconstruction of unobserved states. Our results demonstrate that while all C. difficile-directed antibiotics were associated with similar reductions in alpha diversity, beta diversity significantly differed on the basis of the particular antibiotic, with differentiating relative abundances of bacterial and fungal assemblages. With the exception of fidaxomicin, each antibiotic was associated with the emergence of potentially pathogenic fungal operational taxonomic units, with predicted bacterial functions enriched for xenobiotic metabolism that could perpetuate the dysbiosis driving CDI. Toxin-independent mechanisms of colitis related to the relative abundance of pathogenic bacteria and fungi were also noted. This study suggests that a transkingdom interaction between fungi and bacteria may be important in CDI pathophysiology, including being a factor in the historically high persistence and recurrence rates associated with this disease. IMPORTANCE Using human fecal samples and including sequencing for both bacterial and fungal taxa, this study compared the conventional antibiotics used to treat C. difficile infection (CDI) from the perspective of the microbiome, which is particularly relevant, given the relationship between dysbiotic states and the development of CDI. Sequencing and imputed functional analyses suggest that C. difficile-directed antibiotics are associated with distinct forms of dysbiosis that may be influential in the course of CDI. Further, a role for fungal organisms in the perpetuation of the causal dysbiosis of CDI is discussed, suggesting a previously unappreciated, clinically relevant transkingdom interaction that warrants further study.