Lipoic acid plays a role in scleroderma: insights obtained from scleroderma dermal fibroblasts

Abstract Introduction Systemic sclerosis (SSc) is a connective tissue disease characterized by fibrosis of the skin and organs. Increase in oxidative stress and platelet-derived growth factor receptor (PDGFR) activation promote type I collagen (Col I) production, leading to fibrosis in SSc. Lipoic acid (LA) and its active metabolite dihydrolipoic acid (DHLA) are naturally occurring thiols that act as cofactors and antioxidants and are produced by lipoic acid synthetase (LIAS). Our goals in this study were to examine whether LA and LIAS were deficient in SSc patients and to determine the effect of DHLA on the phenotype of SSc dermal fibroblasts. N-acetylcysteine (NAC), a commonly used thiol antioxidant, was included as a comparison. Methods Dermal fibroblasts were isolated from healthy subjects and patients with diffuse cutaneous SSc. Matrix metalloproteinase (MMPs), tissue inhibitors of MMPs (TIMP), plasminogen activator inhibitor 1 (PAI-1) and LIAS were measured by enzyme-linked immunosorbent assay. The expression of Col I was measured by immunofluorescence, hydroxyproline assay and quantitative PCR. PDGFR phosphorylation and α-smooth muscle actin (αSMA) were measured by Western blotting. Student’s t-tests were performed for statistical analysis, and P-values less than 0.05 with two-tailed analysis were considered statistically significant. Results The expression of LA and LIAS in SSc dermal fibroblasts was lower than normal fibroblasts; however, LIAS was significantly higher in SSc plasma and appeared to be released from monocytes. DHLA lowered cellular oxidative stress and decreased PDGFR phosphorylation, Col I, PAI-1 and αSMA expression in SSc dermal fibroblasts. It also restored the activities of phosphatases that inactivated the PDGFR. SSc fibroblasts produced lower levels of MMP-1 and MMP-3, and DHLA increased them. In contrast, TIMP-1 levels were higher in SSc, but DHLA had a minimal effect. Both DHLA and NAC increased MMP-1 activity when SSc cells were stimulated with PDGF. In general, DHLA showed better efficacy than NAC in most cases. Conclusions DHLA acts not only as an antioxidant but also as an antifibrotic because it has the ability to reverse the profibrotic phenotype of SSc dermal fibroblasts. Our study suggests that thiol antioxidants, including NAC, LA, or DHLA, could be beneficial for patients with SSc.http://deepblue.lib.umich.edu/bitstream/2027.42/112060/1/13075_2014_Article_411.pd

Frontal networks in adults with autism spectrum disorder.

It has been postulated that autism spectrum disorder is underpinned by an 'atypical connectivity' involving higher-order association brain regions. To test this hypothesis in a large cohort of adults with autism spectrum disorder we compared the white matter networks of 61 adult males with autism spectrum disorder and 61 neurotypical controls, using two complementary approaches to diffusion tensor magnetic resonance imaging. First, we applied tract-based spatial statistics, a 'whole brain' non-hypothesis driven method, to identify differences in white matter networks in adults with autism spectrum disorder. Following this we used a tract-specific analysis, based on tractography, to carry out a more detailed analysis of individual tracts identified by tract-based spatial statistics. Finally, within the autism spectrum disorder group, we studied the relationship between diffusion measures and autistic symptom severity. Tract-based spatial statistics revealed that autism spectrum disorder was associated with significantly reduced fractional anisotropy in regions that included frontal lobe pathways. Tractography analysis of these specific pathways showed increased mean and perpendicular diffusivity, and reduced number of streamlines in the anterior and long segments of the arcuate fasciculus, cingulum and uncinate--predominantly in the left hemisphere. Abnormalities were also evident in the anterior portions of the corpus callosum connecting left and right frontal lobes. The degree of microstructural alteration of the arcuate and uncinate fasciculi was associated with severity of symptoms in language and social reciprocity in childhood. Our results indicated that autism spectrum disorder is a developmental condition associated with abnormal connectivity of the frontal lobes. Furthermore our findings showed that male adults with autism spectrum disorder have regional differences in brain anatomy, which correlate with specific aspects of autistic symptoms. Overall these results suggest that autism spectrum disorder is a condition linked to aberrant developmental trajectories of the frontal networks that persist in adult life

Corticospinal excitability and conductivity are related to the anatomy of the corticospinal tract

Probing the brain structure–function relationship is at the heart of modern neuroscientific explorations, enabled by recent advances in brain mapping techniques. This study aimed to explore the anatomical blueprint of corticospinal excitability and shed light on the structure–function relationship within the human motor system. Using diffusion magnetic resonance imaging tractography, based on the spherical deconvolution approach, and transcranial magnetic stimulation (TMS), we show that anatomical inter-individual variability of the corticospinal tract (CST) modulates the corticospinal excitability and conductivity. Our findings show for the first time the relationship between increased corticospinal excitability and conductivity in individuals with a bigger CST (i.e., number of streamlines), as well as increased corticospinal microstructural organization (i.e., fractional anisotropy). These findings can have important implications for the understanding of the neuroanatomical basis of TMS as well as the study of the human motor system in both health and disease

Corticospinal excitability and conductivity are related to the anatomy of the corticospinal tract

Probing the brain structure–function relationship is at the heart of modern neuroscientific explorations, enabled by recent advances in brain mapping techniques. This study aimed to explore the anatomical blueprint of corticospinal excitability and shed light on the structure–function relationship within the human motor system. Using diffusion magnetic resonance imaging tractography, based on the spherical deconvolution approach, and transcranial magnetic stimulation (TMS), we show that anatomical inter-individual variability of the corticospinal tract (CST) modulates the corticospinal excitability and conductivity. Our findings show for the first time the relationship between increased corticospinal excitability and conductivity in individuals with a bigger CST (i.e., number of streamlines), as well as increased corticospinal microstructural organization (i.e., fractional anisotropy). These findings can have important implications for the understanding of the neuroanatomical basis of TMS as well as the study of the human motor system in both health and disease

Sex differences in the effects of MDMA (ecstasy) on plasma copeptin in healthy subjects

BACKGROUND:3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) misuse is associated with hyponatremia particularly in women. Hyponatremia is possibly due to inappropriate secretion of plasma arginine vasopressin (AVP). OBJECTIVE: To assess whether MDMA increases plasma AVP and copeptin in healthy male and female subjects and whether effects depend on MDMA-induced release of serotonin and norepinephrine. Copeptin, the C-terminal part of the AVP precursor preprovasopressin, is cosecreted with AVP and can be determined more reliably. METHODS: We used a randomized placebo-controlled crossover design. Plasma and urine osmolalities as well as AVP and copeptin levels were measured in 16 healthy subjects (eight female, eight male) at baseline and after MDMA (125 mg) administration. In addition, we tested whether effects of MDMA on AVP and copeptin secretion can be prevented by pretreatment with the serotonin and norepinephrine transporter inhibitor duloxetine (120 mg), which blocks MDMA-induced transporter-mediated release of serotonin and norepinephrine. RESULTS: MDMA significantly elevated plasma copeptin levels at 60 min and at 120 min compared with placebo in women but not in men. The copeptin response to MDMA in women was prevented by duloxetine. MDMA also nonsignificantly increased plasma AVP levels in women, and the effect was prevented by duloxetine. Although subjects drank more water after MDMA compared with placebo administration, MDMA tended to increase urine sodium levels and urine osmolality compared with placebo, indicating increased renal water retention. CONCLUSION: MDMA increased plasma copeptin, a marker for AVP secretion, in women but not in men. This sex difference in MDMA-induced AVP secretion may explain why hyponatremia is typically reported in female ecstasy users. The copeptin response to MDMA is likely mediated via MDMA-induced release of serotonin and/or norepinephrine because it was prevented by duloxetine, which blocks the interaction of MDMA with the serotonergic and noradrenergic system

Heritability of the limbic networks

This work was supported by the MRC UK (grant number G0400061) as the AIMS (Autism Imaging Multicentre Study) with support from the National Institute for Health Research (NIHR) Biomedical Research Centre at South London and Maudsley NHS Foundation Trust, King’s College London, and the Sackler Institute for Translational Neurodevelopment. Additional funding was provided by the European Autism Interventions—A Multicentre Study for Developing New Medications (EU-AIMS), which received support from the Innovative Medicines Initiative Joint Undertaking (grant agreement number 115300), including financial contributions from the EU Seventh Framework Programme (FP7/2007-2013), the European Federation of Pharmaceutical Industries and Associations companies in kind, Autism Speaks, NARSAD, The Stanley Foundation, Schizophrenia Research Trust and Psychiatry Research Trust. M.C. is the recipient of a Wellcome Trust Investigator Award (103759/Z/14/Z).Individual differences in cognitive ability and social behaviour are influenced by the variability in the structure and function of the limbic system. A strong heritability of the limbic cortex has been previously reported, but little is known about how genetic factors influence specific limbic networks. We used diffusion tensor imaging tractography to investigate heritability of different limbic tracts in 52 monozygotic and 34 dizygotic healthy adult twins. We explored the connections that contribute to the activity of three distinct functional limbic networks, namely the dorsal cingulum ('medial default-mode network'), the ventral cingulum and the fornix ('hippocampal-diencephalic-retrosplenial network') and the uncinate fasciculus ('temporo-amygdala-orbitofrontal network'). Genetic and environmental variances were mapped for multiple tract-specific measures that reflect different aspects of the underlying anatomy. We report the highest heritability for the uncinate fasciculus, a tract that underpins emotion processing, semantic cognition, and social behaviour. High to moderate genetic and shared environmental effects were found for pathways important for social behaviour and memory, for example, fornix, dorsal and ventral cingulum. These findings indicate that within the limbic system inheritance of specific traits may rely on the anatomy of distinct networks and is higher for fronto-temporal pathways dedicated to complex social behaviour and emotional processing.Publisher PDFPeer reviewe

SMALL-ANGLE SCATTERING CHARACTERIZATION OF DILUTE TO SEMI- DILUTE ARABINOXYLAN POLYSACCHARIDE SOLUTIONS IN WATER

International audienceWe report small-angle neutron scattering (SANS) measurements of aqueous solutions ofneutral arabinoxylan (AX) polysaccharide extracted from wheat flour and prepared atincreasing concentrations. To maximize the hydration of the chains, the solutions are firstprepared at C=1g/L, i.e. below the overlap concentration C*»2-3g/L, and then slowlyconcentrated using osmotic stress until max. ~200g/L, i.e. well above C*. The SANS dataobtained at various concentrations are similar to the one of figure 1, with three distinct q-regions that inform on the structure of the samples at different length-scales: region ❶ thatoriginates from clusters of associated AX chains,1 region ❷ where the chains are in goodsolvent conditions and form an entangled network of correlation length ξ,2 and the high-qregion ❸ where the local conformation and size of the chains are probed (eg. persistencelength). The purpose of the talk is to give a full analysis of these SANS results using appropriatemodels and complementary data of SEC-MALS and rheology. Special focus will be given tothe correlation length ξ and its changes with AX concentration. Our group is indeedconducting studies about the diffusion of objects like enzymes in such concentrated AXsystems. Knowing ξ is this context is of outmost importance as the mobility of a colloidalspecies in a polymer liquid is directly linked to ξ and its associated 'tube' or pore size