Vimentin is a dominant target of in situ humoral immunity in human lupus tubulointerstitial nephritis

OBJECTIVE

In lupus nephritis (LN), severe tubulointerstitial inflammation (TII) predicts progression to renal failure. Severe TII is associated with tertiary lymphoid neogenesis and in situ antigen-driven clonal B cell selection. The autoantigen(s) driving in situ B cell selection in TII are not known. This study was undertaken to identify the dominant driving autoantigen(s).

METHODS

Single CD38+ or Ki-67+ B cells were laser captured from 7 biopsy specimens that were diagnostic for LN. Eighteen clonally expanded immunoglobulin heavy- and light-chain variable region pairs were cloned and expressed as monoclonal antibodies. Seven more antibodies were cloned from flow-sorted CD38+ cells from an eighth biopsy specimen. Antigen characterization was performed using a combination of confocal microscopy, enzyme-linked immunosorbent assay, screening protoarrays, immunoprecipitation, and mass spectrometry. Serum IgG titers to the dominant antigen in 48 LN and 35 non-nephritic lupus samples were determined using purified antigen-coated arrays. Autoantigen expression on normal and LN kidney was localized by immunohistochemistry and immunofluorescence.

RESULTS

Eleven of 25 antibodies reacted with cytoplasmic structures, 4 reacted with nuclei, and none reacted with double-stranded DNA. Vimentin was the only autoantigen identified by both mass spectrometry and protoarray. Ten of the 11 anticytoplasmic TII antibodies directly bound vimentin. Vimentin was highly expressed by tubulointerstitial inflammatory cells, and the TII antibodies tested preferentially bound inflamed tubulointerstitium. Finally, high titers of serum antivimentin antibodies were associated with severe TII (P = 0.0001).

CONCLUSION

Vimentin, an antigenic feature of inflammation, is a dominant autoantigen targeted in situ in LN TII. This adaptive autoimmune response likely feeds forward to worsen TII and renal damage.

Component reductions in oxygen delivery generate variable haemodynamic and stress hormone responses

BACKGROUND

In clinical practice, global oxygen delivery (DO2) is often considered as a whole; however pathological and adaptive responses after a decrease in individual constituents of the DO2 equation (cardiac output, haemoglobin, oxyhaemoglobin saturation) are likely to be diverse. We hypothesized that an equivalent decrease in DO2 after reductions in each separate component of the equation would result in different haemodynamic, tissue oxygenation, and stress hormonal responses.

METHODS

Anaesthetized, fluid-resuscitated male Wistar rats were subjected to circulatory, anaemic, or hypoxic hypoxia (by haemorrhage, isovolaemic haemodilution, and breathing a hypoxic gas mix, respectively), produced either rapidly over 5 min or graded over 30 min, to a targeted 50% decrease in global oxygen delivery. Sham-operated animals acted as controls. Measurements were made of haemodynamics, skeletal muscle tissue oxygen tension, blood gas analysis, and circulating stress hormone levels.

RESULTS

Whereas haemorrhage generated the largest decrease in cardiac output, and the greatest stress hormone response, haemodilution had the most marked effect on arterial pressure. In contrast, rapid hypoxaemia produced a minor impact on global haemodynamics yet induced the greatest decrease in regional oxygenation. A greater degree of hyperlactataemia was observed with graded insults compared with those administered rapidly.

CONCLUSIONS

Decreasing global oxygen delivery, achieved by targeted reductions in its separate components, induces varying circulatory, tissue oxygen tension, and stress hormone responses. We conclude that not all oxygen delivery is the same; this disparity should be emphasized in classical teaching and re-evaluated in patient management.

Brain activation to cocaine cues and motivation/treatment status

Motivation to change is believed to be a key factor in therapeutic success in substance use disorders; however, the neurobiological mechanisms through which motivation to change impacts decreased substance use remain unclear. Existing research is conflicting, with some investigations supporting decreased and others reporting increased frontal activation to drug cues in individuals seeking treatment for substance use disorders. The present study investigated the relationship between motivation to change cocaine use and cue-elicited brain activity in cocaine-dependent individuals using two conceptualizations of 'motivation to change': (1) current treatment status (i.e. currently receiving versus not receiving outpatient treatment for cocaine dependence) and (2) self-reported motivation to change substance use, using the Stages of Change Readiness and Treatment Eagerness Scale. Thirty-eight cocaine-dependent individuals (14 currently in treatment) completed a diagnostic assessment and an fMRI cocaine cue-reactivity task. Whole-brain analyses demonstrated that both treatment-seeking and motivated participants had lower activation to cocaine cues in a wide variety of brain regions in the frontal, occipital, temporal and cingulate cortices relative to non-treatment-seeking and less motivated participants. Future research is needed to explain the mechanism by which treatment and/or motivation impacts neural cue reactivity, as such work could potentially aid in the development of more effective therapeutic techniques for substance-dependent patients.

Impact of DCS-facilitated cue exposure therapy on brain activation to cocaine cues in cocaine dependence

BACKGROUND

The development of addiction is marked by a pathological associative learning process that imbues incentive salience to stimuli associated with drug use. Recent efforts to treat addiction have targeted this learning process using cue exposure therapy augmented with d-cycloserine (DCS), a glutamatergic agent hypothesized to enhance extinction learning. To better understand the impact of DCS-facilitated extinction on neural reactivity to drug cues, the present study reports fMRI findings from a randomized, double-blind, placebo-controlled trial of DCS-facilitated cue exposure for cocaine dependence.

METHODS

Twenty-five participants completed two MRI sessions (before and after intervention), with a cocaine-cue reactivity fMRI task. The intervention consisted of 50mg of DCS or placebo, combined with two sessions of cocaine cue exposure and skills training.

RESULTS

Participants demonstrated cocaine cue activation in a variety of brain regions at baseline. From the pre- to post-study scan, participants experienced decreased activation to cues in a number of regions (e.g., accumbens, caudate, frontal poles). Unexpectedly, placebo participants experienced decreases in activation to cues in the left angular and middle temporal gyri and the lateral occipital cortex, while DCS participants did not.

CONCLUSIONS

Three trials of DCS-facilitated cue exposure therapy for cocaine dependence have found that DCS either increases or does not significantly impact response to cocaine cues. The present study adds to this literature by demonstrating that DCS may prevent extinction to cocaine cues in temporal and occipital brain regions. Although consistent with past research, results from the present study should be considered preliminary until replicated in larger samples.

Prospective associations between brain activation to cocaine and no-go cues and cocaine relapse

BACKGROUND

The ability to predict potential for relapse to substance use following treatment could be very useful in targeting aftercare strategies. Recently, a number of investigators have focused on using neural activity measured by fMRI to predict relapse propensity. The purpose of the present study was to use fMRI to investigate prospective associations between brain reactivity to cocaine and response inhibition cues and relapse to cocaine use.

METHODS

Thirty cocaine-dependent participants with clean cocaine urine drug screens (UDS) completed a baseline fMRI scan, including a cocaine-cue reactivity task and a go no-go response inhibition task. After participating in a brief clinical trial of d-cycloserine for the facilitation of cocaine-cue extinction, they returned for a one-week follow-up UDS. Associations between baseline activation to cocaine and inhibition cues and relapse to cocaine use were explored.

RESULTS

Positive cocaine UDS was significantly associated with cocaine-cue activation in the right putamen and insula, as well as bilateral occipital regions. Associations between positive cocaine UDS and activation to no-go cues were concentrated in the postcentral gyri, a region involved in response execution.

CONCLUSIONS

Although preliminary, these results suggest that brain imaging may be a useful tool for predicting risk for relapse in cocaine-dependent individuals. Further, larger-scale naturalistic studies are needed to corroborate and extend these findings.

Effects of a GABA-ergic medication combination and initial alcohol withdrawal severity on cue-elicited brain activation among treatment-seeking alcoholics

RATIONALE

Many studies have reported medication effects on alcohol cue-elicited brain activation or associations between such activation and subsequent drinking. However, few have combined the methodological rigor of a randomized clinical trial (RCT) with follow-up assessments to determine whether cue-elicited activation predicts relapse during treatment, the crux of alcoholism.

OBJECTIVES

This study analyzed functional magnetic resonance imaging (fMRI) data from 48 alcohol-dependent subjects enrolled in a 6-week RCT of an investigational pharmacotherapy.

METHODS

Subjects were randomized, based on their level of alcohol withdrawal (AW) at study entry, to receive either a combination of gabapentin (GBP; up to 1,200 mg for 39 days) and flumazenil (FMZ) infusions (2 days) or two placebos. Midway through the RCT, subjects were administered an fMRI alcohol cue reactivity task.

RESULTS

There were no main effects of medication or initial AW status on cue-elicited activation, but these factors interacted, such that the GBP/FMZ/higher AW and placebo/lower AW groups, which had previously been shown to have relatively reduced drinking, demonstrated greater dorsal anterior cingulate cortex (dACC) activation to alcohol cues. Further analysis suggested that this finding represented differences in task-related deactivation and was associated with greater control over alcohol-related thoughts. Among study completers, regardless of medication or AW status, greater left dorsolateral prefrontal cortex (DLPFC) activation predicted more post-scan heavy drinking.

CONCLUSIONS

These data suggest that alterations in task-related deactivation of dACC, a component of the default mode network, may predict better alcohol treatment response, while activation of DLPFC, an area associated with selective attention, may predict relapse drinking.

Australia's mental health legislation

Australia has a generally progressive approach to mental health law, reflective of international trends in human rights. Responsibility for most legislation is vested in the six States and two Territories, a total of eight jurisdictions, such that at any given time several new mental health acts are in preparation. In addition there is a model mental health act that promotes common standards. Transfer of orders between jurisdictions relies on Memoranda of Understanding between them, and is patchy. State and Territory legislation is generally cognisant of international treaty obligations, which are themselves the preserve of the Federal Parliament and legislature. UK legislation has had a key influence in Australia, the 1959 Mental Health Act in particular, with its strong emphasis on voluntary hospitalisation, prefacing deinstitutionalisation.

Australia's mental health legislation

Australia has a generally progressive approach to mental health law, reflective of international trends in human rights. Responsibility for most legislation is vested in the six States and two Territories, a total of eight jurisdictions, such that at any given time several new mental health acts are in preparation. In addition there is a model mental health act that promotes common standards. Transfer of orders between jurisdictions relies on Memoranda of Understanding between them, and is patchy. State and Territory legislation is generally cognisant of international treaty obligations, which are themselves the preserve of the Federal Parliament and legislature. UK legislation has had a key influence in Australia, the 1959 Mental Health Act in particular, with its strong emphasis on voluntary hospitalisation, prefacing deinstitutionalisation.