Fornix Microstructure and Memory Performance Is Associated with Altered Neural Connectivity during Episodic Recognition.

OBJECTIVES: The purpose of this study was to assess whether age-related differences in white matter microstructure are associated with altered task-related connectivity during episodic recognition. METHODS: Using functional magnetic resonance imaging and diffusion tensor imaging from 282 cognitively healthy middle-to-late aged adults enrolled in the Wisconsin Registry for Alzheimer's Prevention, we investigated whether fractional anisotropy (FA) within white matter regions known to decline with age was associated with task-related connectivity within the recognition network. RESULTS: There was a positive relationship between fornix FA and memory performance, both of which negatively correlated with age. Psychophysiological interaction analyses revealed that higher fornix FA was associated with increased task-related connectivity amongst the hippocampus, caudate, precuneus, middle occipital gyrus, and middle frontal gyrus. In addition, better task performance was associated with increased task-related connectivity between the posterior cingulate gyrus, middle frontal gyrus, cuneus, and hippocampus. CONCLUSIONS: The findings indicate that age has a negative effect on white matter microstructure, which in turn has a negative impact on memory performance. However, fornix microstructure did not significantly mediate the effect of age on performance. Of interest, dynamic functional connectivity was associated with better memory performance. The results of the psychophysiological interaction analysis further revealed that alterations in fornix microstructure explain-at least in part-connectivity among cortical regions in the recognition memory network. Our results may further elucidate the relationship between structural connectivity, neural function, and cognition.

Preliminary clinical findings on NEUMUNE as a potential treatment for acute radiation syndrome.

5-androstenediol (5-AED) has been advanced as a possible countermeasure for treating the haematological component of acute radiation syndrome (ARS). It has been used in animal models to stimulate both innate and adaptive immunity and treat infection and radiation-induced immune suppression. We here report on the safety, tolerability and haematologic activity of 5-AED in four double-blinded, randomized, placebo-controlled studies on healthy adults including elderly subjects. A 5-AED injectable suspension formulation (NEUMUNE) or placebo was administered intramuscularly as either a single injection, or once daily for five consecutive days at doses of 50, 100, 200 or 400 mg. Subjects (n = 129) were randomized to receive NEUMUNE (n = 95) or the placebo (n = 34). NEUMUNE was generally well-tolerated; the most frequent adverse events were local injection site reactions (n = 104, 81%) that were transient, dose-volume dependent, mild to moderate in severity, and that resolved over the course of the study. Blood chemistries revealed a transient increase (up to 28%) in creatine phosphokinase and C-reactive protein levels consistent with intramuscular injection and injection site irritation. The blood concentration profile of 5-AED is consistent with a depot formulation that increases in disproportionate increments following each dose. NEUMUNE significantly increased circulating neutrophils (p < 0.001) and platelets (p < 0.001) in the peripheral blood of adult and elderly subjects. A dose-response relationship was identified. Findings suggest that parenteral administration of 5-AED in aqueous suspension may be a safe and effective means to stimulate innate immunity and alleviate neutropenia and thrombocytopenia associated with ARS.

Longitudinal development of thalamic and internal capsule microstructure in autism spectrum disorder.

The thalamus is a key sensorimotor relay area that is implicated in autism spectrum disorder (ASD). However, it is unknown how the thalamus and white-matter structures that contain thalamo-cortical fiber connections (e.g., the internal capsule) develop from childhood into adulthood and whether this microstructure relates to basic motor challenges in ASD. We used diffusion weighted imaging in a cohort-sequential design to assess longitudinal development of the thalamus, and posterior- and anterior-limbs of the internal capsule (PLIC and ALIC, respectively) in 89 males with ASD and 56 males with typical development (3-41 years; all verbal). Our results showed that the group with ASD exhibited different developmental trajectories of microstructure in all regions, demonstrating childhood group differences that appeared to approach and, in some cases, surpass the typically developing group in adolescence and adulthood. The PLIC (but not ALIC nor thalamus) mediated the relation between age and finger-tapping speed in both groups. Yet, the gap in finger-tapping speed appeared to widen at the same time that the between-group gap in the PLIC appeared to narrow. Overall, these results suggest that childhood group differences in microstructure of the thalamus and PLIC become less robust in adolescence and adulthood. Further, finger-tapping speed appears to be mediated by the PLIC in both groups, but group differences in motor speed that widen during adolescence and adulthood suggest that factors beyond the microstructure of the thalamus and internal capsule may contribute to atypical motor profiles in ASD. Autism Res 2018, 11: 450-462. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Microstructure of the thalamus, a key sensory and motor brain area, appears to develop differently in individuals with autism spectrum disorder (ASD). Microstructure is important because it informs us of the density and organization of different brain tissues. During childhood, thalamic microstructure was distinct in the ASD group compared to the typically developing group. However, these group differences appeared to narrow with age, suggesting that the thalamus continues to dynamically change in ASD into adulthood.

Cerebral white matter structure is disrupted in Gulf War Veterans with chronic musculoskeletal pain.

Chronic musculoskeletal pain (CMP) affects ∼25% of the 700,000 Veterans deployed during the Persian Gulf War (1990-1991). The cause of their pain is unknown, and there are no efficacious treatments. A small body of literature suggests that brain abnormalities exist in Gulf War Veterans (GVs), yet relationships between brain abnormalities and disease symptoms remain largely unexplored. Our purpose was to compare white matter (WM) integrity between GVCMP and matched, healthy Veteran controls (GVCO) and investigate relationships between cerebral WM integrity and symptoms. Thirty GVCMP and 31 controls completed magnetic resonance imaging with diffusion tensor imaging. Tract-based spatial statistics estimated WM fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity over the whole brain (P < 0.05) and were corrected using threshold-free cluster enhancement. GVCMP had greater pain symptoms and mood disturbance and lower quality of life and physical function compared with GVCO (P < 0.05). GVCMP had lower WM integrity across several brain regions implicated in chronic pain (P < 0.05) including the middle and inferior frontal gyrus, corpus callosum, corona radiata, precentral gyrus, external capsule, and posterior thalamic radiation. For GVCMP, WM integrity was associated with pain and mood symptoms in widespread brain areas that were found to be different between groups (P < 0.05). Results indicate widespread WM microstructure disruption across brain regions implicated in pain processing and modulation in chronic pain. The observed relationships between WM microstructure and symptoms encourage the testing of treatments designed to improve the brain health of affected Veterans.

Investigating the Microstructural Correlation of White Matter in Autism Spectrum Disorder.

White matter microstructure forms a complex and dynamical system that is critical for efficient and synchronized brain function. Neuroimaging findings in children with autism spectrum disorder (ASD) suggest this condition is associated with altered white matter microstructure, which may lead to atypical macroscale brain connectivity. In this study, we used diffusion tensor imaging measures to examine the extent that white matter tracts are interrelated within ASD and typical development. We assessed the strength of inter-regional white matter correlations between typically developing and ASD diagnosed individuals. Using hierarchical clustering analysis, clustering patterns of the pairwise white matter correlations were constructed and revealed to be different between the two groups. Additionally, we explored the use of graph theory analysis to examine the characteristics of the patterns formed by inter-regional white matter correlations and compared these properties between ASD and typical development. We demonstrate that the ASD sample has significantly less coherence in white matter microstructure across the brain compared to that in the typical development sample. The ASD group also presented altered topological characteristics, which may implicate less efficient brain networking in ASD. These findings highlight the potential of graph theory based network characteristics to describe the underlying networks as measured by diffusion magnetic resonance imaging and furthermore indicates that ASD may be associated with altered brain network characteristics. Our findings are consistent with those of a growing number of studies and hypotheses that have suggested disrupted brain connectivity in ASD.

Cerebrospinal Fluid Markers of Alzheimer's Disease Pathology and Microglial Activation are Associated with Altered White Matter Microstructure in Asymptomatic Adults at Risk for Alzheimer's Disease.

BACKGROUND: The immune response in Alzheimer's disease (AD) involves activation of microglia which may remove amyloid-ß (Aß). However, overproduction of inflammatory compounds may exacerbate neural damage in AD. AD pathology accumulates years before diagnosis, yet the extent to which neuroinflammation is involved in the earliest disease stages is unknown. OBJECTIVE: To determine whether neuroinflammation exacerbates neural damage in preclinical AD. METHODS: We utilized cerebrospinal fluid (CSF) and magnetic resonance imaging collected in 192 asymptomatic late-middle-aged adults (mean age = 60.98 years). Neuroinflammatory markers chitinase-3-like protein 1 (YKL-40) and monocyte chemoattractant protein-1 (MCP-1) in CSF were utilized as markers of neuroinflammation. Neural cell damage was assessed using CSF neurofilament light chain protein (NFL), CSF total tau (T-Tau), and neural microstructure assessed with diffusion tensor imaging (DTI). With regard to AD pathology, CSF Aß42 and tau phosphorylated at threonine 181 (P-Tau181) were used as markers of amyloid and tau pathology, respectively. We hypothesized that higher YKL-40 and MCP-1 in the presence of AD pathology would be associated with higher NFL, T-Tau, and altered microstructure on DTI. RESULTS: Neuroinflammation was associated with markers of neural damage. Higher CSF YKL-40 was associated with both higher CSF NFL and T-Tau. Inflammation interacted with AD pathology, such that greater MCP-1 and lower Aß42 was associated with altered microstructure in bilateral frontal and right temporal lobe and that greater MCP-1 and greater P-Tau181 was associated with altered microstructure in precuneus. CONCLUSION: Inflammation may play a role in neural damage in preclinical AD.

White matter microstructure in late middle-age: Effects of apolipoprotein E4 and parental family history of Alzheimer's disease.

INTRODUCTION: Little is still known about the effects of risk factors for Alzheimer's disease (AD) on white matter microstructure in cognitively healthy adults. The purpose of this cross-sectional study was to assess the effect of two well-known risk factors for AD, parental family history and APOE4 genotype. METHODS: This study included 343 participants from the Wisconsin Registry for Alzheimer's Prevention, who underwent diffusion tensor imaging (DTI). A region of interest analysis was performed on fractional anisotropy maps, in addition to mean, radial, and axial diffusivity maps, aligned to a common template space using a diffeomorphic, tensor-based registration method. The analysis focused on brain regions known to be affected in AD including the corpus callosum, superior longitudinal fasciculus, fornix, cingulum, and uncinate fasciculus. Analyses assessed the impact of APOE4, parental family history of AD, age, and sex on white matter microstructure in late middle-aged participants (aged 47-76 years). RESULTS: Both APOE4 and parental family history were associated with microstructural white matter differences. Participants with parental family history of AD had higher FA in the genu of the corpus callosum and the superior longitudinal fasciculus. We observed an interaction between family history and APOE4, where participants who were family history positive but APOE4 negative had lower axial diffusivity in the uncinate fasciculus, and participants who were both family history positive and APOE4 positive had higher axial diffusivity in this region. We also observed an interaction between APOE4 and age, whereby older participants (=65 years of age) who were APOE4 carriers, had higher MD in the superior longitudinal fasciculus and in the portion of the cingulum bundle running adjacent to the cingulate cortex, compared to non-carriers. Older participants who were APOE4 carriers also showed higher radial diffusivity in the genu compared to non-carriers. Across all participants, age had an effect on FA, MD, and axial and radial diffusivities. Sex differences were observed in FA and radial diffusivity. CONCLUSION: APOE4 genotype, parental family history of AD, age, and sex are all associated with microstructural white matter differences in late middle-aged adults. In participants at risk for AD, alterations in diffusion characteristics-both expected and unexpected-may represent cellular changes occurring at the earliest disease stages, but further work is needed. Higher mean, radial, and axial diffusivities were observed in participants who are more likely to be experiencing later stage preclinical pathology, including participants who were both older and carried APOE4, or who were positive for both APOE4 and parental family history of AD.

A synthetic anti-inflammatory sterol improves insulin sensitivity in insulin-resistant obese impaired glucose tolerance subjects.

OBJECTIVE: To study the activity of HE3286 (17α-ethynylandrost-5-ene-3ß,7ß,17ß-triol), an anti-inflammatory sterol that is active in models of obesity-induced inflammation and insulin resistance in high body mass index (BMI) subjects with impaired glucose tolerance (IGT). DESIGN AND METHODS: HE3286 was explored in high BMI IGT subjects using hyperinsulinemic, euglycemic clamp studies. RESULTS: In insulin-resistant subjects, HE3286 significantly increased day 29 insulin-stimulated glucose disposal and HDL cholesterol, and decreased C-reactive protein (CRP) compared to placebo. For HE3286, change in M value showed a significant negative correlation with baseline M value. Subjects with baseline M value below the median (4.2 mg/kg/min) had significantly lower adiponectin and higher lipopolysaccharide-stimulated peripheral blood mononuclear cell cytokine secretion. After 28 days of HE3286 treatment, adiponectin levels were significantly increased in insulin-resistant (baseline M < 4.2), but not insulin-sensitive (baseline M > 4.2) subjects, compared to placebo. CONCLUSIONS: HE3286 significantly increased the frequency of subjects with increased insulin-stimulated glucose disposal and HDL, and decreased CRP compared to placebo, in insulin-resistant, but not insulin-sensitive subjects. Thus, HE3286 may preferentially benefit insulin-resistant, inflamed, high BMI IGT subjects.

Oral treatment with HE3286 ameliorates disease in rodent models of rheumatoid arthritis.

HE3286 (17alpha-ethynyl-5-androstene-3beta, 7beta, 17beta-triol) is an orally bio-available synthetic derivative of naturally occurring androstene-3beta, 7beta, 17beta-triol. Our present data show that oral treatment with HE3286, favourably influenced the course of arthritis in the rat model of adjuvant-induced arthritis (reduced cumulative disease scores and paw edema), and in the mouse model of collagen antibody-induced arthritis (reduced clinical paw scores). Importantly, HE3286 was not immune suppressive in human mixed lymphocyte reaction or in animals challenged with Coxsackie B3 virus. HE3286 is currently in phase I/II clinical trials in rheumatoid arthritis and ulcerative colitis and these findings further strengthen the possibility that HE3286 may represent an effective anti-inflammatory agent useful for treating chronic inflammation with a more attractive safety profile than glucocorticoids or cyclooxygenase inhibitors.

Safety and activity of the immune modulator HE2000 on the incidence of tuberculosis and other opportunistic infections in AIDS patients.

Twenty-five AIDS patients were treated with HE2000, a synthetic adrenal hormone. The drug was well tolerated and safe and reduced both the incidence of tuberculosis coinfection by 42.2% (P < 0.05) and the cumulative incidence of opportunistic infections (P < 0.05). These results warrant further clinical investigation of HE2000.

Prevalence of birth defects among infants of Gulf War veterans in Arkansas, Arizona, California, Georgia, Hawaii, and Iowa, 1989-1993.

BACKGROUND: Epidemiologic studies of birth defects among infants of Gulf War veterans (GWV) have been limited to military hospitals, anomalies diagnosed among newborns, or self-reported data. This study was conducted to measure the prevalence of birth defects among infants of GWVs and nondeployed veterans (NDV) in states that conducted active case ascertainment of birth defects between 1989-93. METHODS: Military records of 684,645 GWVs and 1,587,102 NDVs were electronically linked with 2,314,908 birth certficates from Arizona, Hawaii, Iowa, and selected counties of Arkansas, California, and Georgia; 11,961 GWV infants and 33,052 NDV infants were identified. Of these, 450 infants had mothers who served in the Gulf War, and 3966 had NDV mothers. RESULTS: Infants conceived postwar to male GWVs had significantly higher prevalence of tricuspid valve insufficicieny (relative risk [RR], 2.7; 95% confidence interval [CI], 1.1-6.6; p = 0.039) and aortic valve stenosis (RR, 6.0; 95% CI, 1.2-31.0; p = 0.026) compared to infants conceived postwar to NDV males. Among infants of male GWVs, aortic valve stenosis (RR, 163; 95% CI, 0.09-294; p = 0.011) and renal agenesis or hypoplasia (RR, 16.3; 95% CI, 0.09-294; p = 0.011) were significantly higher among infants conceived postwar than prewar. Hypospadias was significantly higher among infant sons conceived postwar to GWV women compared to NDV women (RR, 6.3; 95% CI, 1.5-26.3; p = 0.015). CONCLUSION: We observed a higher prevalence of tricuspid valve insufficiency, aortic valve stenosis, and renal agenesis or hypoplasia among infants conceived postwar to GWV men, and a higher prevalence of hypospadias among infants conceived postwar to female GWVs. We did not have the ability to determine if the excess was caused by inherited or environmental factors, or was due to chance because of myriad reasons, including multiple comparisons. Although the statistical power was sufficient to compare the combined birth defects prevalence, larger sample sizes were needed for less frequent individual component defects.