Benzodiazepine Use Is Associated With Poorer Spinal Cord Stimulation Outcome in 373 Neuropathic Pain Patients.

OBJECTIVES: The aim of the study is to investigate whether benzodiazepine use differs between patients with favorable and unfavorable spinal cord stimulation (SCS) treatment outcome. We hypothesize that the patients with unfavorable SCS outcome would exhibit a higher level of benzodiazepine use. MATERIALS AND METHODS: Using a case-control study setting, we examined benzodiazepine use in SCS patients and in matched population controls as a potential risk factor poor SCS outcome. A total of 373 consecutive SCS patients treated in Kuopio University Hospital between 1997 and 2014 and their 1117 matched population controls were followed until patient death or the end of March 2016. RESULTS: Benzodiazepines were used during the 24-month period before or after SCS implantation by 42.3% of the SCS patients who had the device explanted, 39.5% who had an unsuccessful trial stimulation, 28.0% who still had the device at the end of the follow-up period, and 8.0% of the controls. Diazepam use before SCS increased the odds for explanting of SCS by 2.4-fold (95% Cl: 1.0-5.4). Starting clonazepam use after SCS was associated with a 5.2-fold (95% CI: 1.5-18.9) increase in the odds of unsuccessful trial stimulation. CONCLUSION: The benzodiazepine use in patients with poor SCS outcome illustrates the role of anxiety in SCS outcomes and the need for multidisciplinary treatment of pain.

High Level of Childhood Trauma Predicts a Poor Response to Spinal Cord Stimulation in Chronic Neuropathic Pain.

BACKGROUND: Spinal cord stimulation (SCS) relieves pain by delivering doses of electric current to the dorsal column of the spinal cord and has been found to be most effective in the treatment of neuropathic pain. Psychological distress is a significant risk factor for the development of chronic pain and has been found to affect the outcome of SCS. Childhood trauma is a risk factor for chronic pain, but has not previously been studied in SCS patients. OBJECTIVES: The objective of this prospective registry-based study was to investigate the prevalence of 5 domains of childhood trauma (emotional neglect, emotional abuse, physical neglect, physical abuse, and sexual abuse) and their relationship with the outcome of spinal cord stimulation on patients suffering from treatment-resistant chronic pain. METHODS: SCS patients treated at Kuopio University Hospital between 1/1/2015 and 12/31/2016 were sent a survey in the mail, the Trauma and Distress Scale, assessing childhood trauma (n = 43). Neuropathic pain, disability, anxiety, and depression were measured in the patients pre-surgery and at 6 and 12 months post-surgery. The patients who provided their name on the questionnaire (n = 22) and had suffered from 3 or more domains of trauma were grouped as the high-trauma group (n = 13) and the rest as the low-trauma group (n = 9). RESULTS: The questionnaire was completed by 40 patients (93%). At least 1 domain of trauma was experienced by 35 (88%) patients, and at least 2 by 24 (60%). The low-trauma group displayed a statistically significant decrease in the mean PainDETECT score from 21.5 before SCS to 16.5 at 12 months post-surgery (Wilk's lambda = 0.297, F(2,9) = 10.6, P = 0.004), contrary to the high- trauma group (Wilk's lambda = 0.904, F(2,6) = 0.3, P = 0.739). LIMITATIONS: Only 22 of the 40 patients provided their name on the questionnaire, which decreased the sample size on follow-up. CONCLUSION: This was the first study to investigate childhood trauma in SCS patients. Patients who had experienced high amounts of childhood trauma did not experience any relief from neuropathic pain 12 months' post-SCS, contrary to the low-trauma group. Childhood trauma might be a factor worth screening in the preoperative evaluation and aftercare of SCS candidates. KEY WORDS: Spinal cord stimulation, the Trauma and Distress Scale, chronic pain, childhood trauma, childhood abuse, childhood neglect, chronic back pain, back pain, psychological distress, neuropathic pain.

Robustness of the Process of Nucleoid Exclusion of Protein Aggregates in Escherichia coli.

UNLABELLED: Escherichia coli segregates protein aggregates to the poles by nucleoid exclusion. Combined with cell divisions, this generates heterogeneous aggregate distributions in subsequent cell generations. We studied the robustness of this process with differing medium richness and antibiotics stress, which affect nucleoid size, using multimodal, time-lapse microscopy of live cells expressing both a fluorescently tagged chaperone (IbpA), which identifies in vivo the location of aggregates, and HupA-mCherry, a fluorescent variant of a nucleoid-associated protein. We find that the relative sizes of the nucleoid's major and minor axes change widely, in a positively correlated fashion, with medium richness and antibiotic stress. The aggregate's distribution along the major cell axis also changes between conditions and in agreement with the nucleoid exclusion phenomenon. Consequently, the fraction of aggregates at the midcell region prior to cell division differs between conditions, which will affect the degree of asymmetries in the partitioning of aggregates between cells of future generations. Finally, from the location of the peak of anisotropy in the aggregate displacement distribution, the nucleoid relative size, and the spatiotemporal aggregate distribution, we find that the exclusion of detectable aggregates from midcell is most pronounced in cells with mid-sized nucleoids, which are most common under optimal conditions. We conclude that the aggregate management mechanisms of E. coli are significantly robust but are not immune to stresses due to the tangible effect that these have on nucleoid size. IMPORTANCE: Escherichia coli segregates protein aggregates to the poles by nucleoid exclusion. From live single-cell microscopy studies of the robustness of this process to various stresses known to affect nucleoid size, we find that nucleoid size and aggregate preferential locations change concordantly between conditions. Also, the degree of influence of the nucleoid on aggregate positioning differs between conditions, causing aggregate numbers at midcell to differ in cell division events, which will affect the degree of asymmetries in the partitioning of aggregates between cells of future generations. Finally, we find that aggregate segregation to the cell poles is most pronounced in cells with mid-sized nucleoids. We conclude that the energy-free process of the midcell exclusion of aggregates partially loses effectiveness under stressful conditions.

In vivo transcription kinetics of a synthetic gene uninvolved in stress-response pathways in stressed Escherichia coli cells.

The fast adaptation of Escherichia coli to stressful environments includes the regulation of gene expression rates, mainly of transcription, by specific and global stress-response mechanisms. To study the effects of mechanisms acting on a global level, we observed with single molecule sensitivity the effects of mild acidic shift and oxidative stress on the in vivo transcription dynamics of a probe gene encoding an RNA target for MS2d-GFP, under the control of a synthetic promoter. After showing that this promoter is uninvolved in fast stress-response pathways, we compared its kinetics of transcript production under stress and in optimal conditions. We find that, following the application of either stress, the mean rates of transcription activation and of subsequent RNA production of the probe gene are reduced, particularly under oxidative stress. Meanwhile, the noise in RNA production decreases under oxidative stress, but not under acidic shift. From distributions of intervals between consecutive RNA productions, we infer that the number and duration of the rate-limiting steps in transcription initiation change, following the application of stress. These changes differ in the two stress conditions and are consistent with the changes in noise in RNA production. Overall, our measurements of the transcription initiation kinetics of the probe gene indicate that, following sub-lethal stresses, there are stress-specific changes in the dynamics of transcription initiation of the probe gene that affect its mean rate and noise of transcript production. Given the non-involvement of the probe gene in stress-response pathways, we suggest that these changes are caused by global response mechanisms of E. coli to stress.