Effect of Pain Reprocessing Therapy vs Placebo and Usual Care for Patients With Chronic Back Pain: A Randomized Clinical Trial.

Importance: Chronic back pain (CBP) is a leading cause of disability, and treatment is often ineffective. Approximately 85% of cases are primary CBP, for which peripheral etiology cannot be identified, and maintenance factors include fear, avoidance, and beliefs that pain indicates injury. Objective: To test whether a psychological treatment (pain reprocessing therapy [PRT]) aiming to shift patients' beliefs about the causes and threat value of pain provides substantial and durable pain relief from primary CBP and to investigate treatment mechanisms. Design, Setting, and Participants: This randomized clinical trial with longitudinal functional magnetic resonance imaging (fMRI) and 1-year follow-up assessment was conducted in a university research setting from November 2017 to August 2018, with 1-year follow-up completed by November 2019. Clinical and fMRI data were analyzed from January 2019 to August 2020. The study compared PRT with an open-label placebo treatment and with usual care in a community sample. Interventions: Participants randomized to PRT participated in 1 telehealth session with a physician and 8 psychological treatment sessions over 4 weeks. Treatment aimed to help patients reconceptualize their pain as due to nondangerous brain activity rather than peripheral tissue injury, using a combination of cognitive, somatic, and exposure-based techniques. Participants randomized to placebo received an open-label subcutaneous saline injection in the back; participants randomized to usual care continued their routine, ongoing care. Main Outcomes and Measures: One-week mean back pain intensity score (0 to 10) at posttreatment, pain beliefs, and fMRI measures of evoked pain and resting connectivity. Results: At baseline, 151 adults (54% female; mean [SD] age, 41.1 [15.6] years) reported mean (SD) pain of low to moderate severity (mean [SD] pain intensity, 4.10 [1.26] of 10; mean [SD] disability, 23.34 [10.12] of 100) and mean (SD) pain duration of 10.0 (8.9) years. Large group differences in pain were observed at posttreatment, with a mean (SD) pain score of 1.18 (1.24) in the PRT group, 2.84 (1.64) in the placebo group, and 3.13 (1.45) in the usual care group. Hedges g was -1.14 for PRT vs placebo and -1.74 for PRT vs usual care (P < .001). Of 151 total participants, 33 of 50 participants (66%) randomized to PRT were pain-free or nearly pain-free at posttreatment (reporting a pain intensity score of 0 or 1 of 10), compared with 10 of 51 participants (20%) randomized to placebo and 5 of 50 participants (10%) randomized to usual care. Treatment effects were maintained at 1-year follow-up, with a mean (SD) pain score of 1.51 (1.59) in the PRT group, 2.79 (1.78) in the placebo group, and 3.00 (1.77) in the usual care group. Hedges g was -0.70 for PRT vs placebo (P = .001) and -1.05 for PRT vs usual care (P < .001) at 1-year follow-up. Longitudinal fMRI showed (1) reduced responses to evoked back pain in the anterior midcingulate and the anterior prefrontal cortex for PRT vs placebo; (2) reduced responses in the anterior insula for PRT vs usual care; (3) increased resting connectivity from the anterior prefrontal cortex and the anterior insula to the primary somatosensory cortex for PRT vs both control groups; and (4) increased connectivity from the anterior midcingulate to the precuneus for PRT vs usual care. Conclusions and Relevance: Psychological treatment centered on changing patients' beliefs about the causes and threat value of pain may provide substantial and durable pain relief for people with CBP. Trial Registration: ClinicalTrials.gov Identifier: NCT03294148.

"Microbiota, symbiosis and individuality summer school" meeting report.

How does microbiota research impact our understanding of biological individuality? We summarize the interdisciplinary summer school on "Microbiota, symbiosis and individuality: conceptual and philosophical issues" (July 2019), which was supported by a European Research Council starting grant project "Immunity, DEvelopment, and the Microbiota" (IDEM). The summer school centered around interdisciplinary group work on four facets of microbiota research: holobionts, individuality, causation, and human health. The conceptual discussion of cutting-edge empirical research provided new insights into microbiota and highlights the value of incorporating into meetings experts from other disciplines, such as philosophy and history of science. Video Abstract.

Body size and symbiotic status influence gonad development in Aiptasia pallida anemones.

Pale anemones (Aiptasia pallida) coexist with dinoflagellates (primarily Symbiodinium minutum) in a mutualistic relationship. The purpose of this study was to investigate the role of these symbionts in gonad development of anemone hosts. Symbiotic and aposymbiotic anemones were subjected to light cycles that induced gametogenesis. These anemones were then sampled weekly for nine weeks, and gonad development was analyzed histologically. Anemone size was measured as mean body column diameter, and oocytes or sperm follicles were counted for each anemone. Generalized linear models were used to evaluate the influence of body size and symbiotic status on whether gonads were present and on the number of oocytes or sperm follicles produced. Body size predicted whether gonads were present, with larger anemones being more likely than smaller anemones to develop gonads. Both body size and symbiotic status predicted gonad size, such that larger and symbiotic anemones produced more oocytes and sperm follicles than smaller and aposymbiotic anemones. Overall, only 22 % of aposymbiotic females produced oocytes, whereas 63 % of symbiotic females produced oocytes. Similarly, 6 % of aposymbiotic males produced sperm follicles, whereas 60 % of symbiotic males produced sperm follicles. Thus, while gonads were present in 62 % of symbiotic anemones, they were present in only 11 % of aposymbiotic anemones. These results indicate that dinoflagellate symbionts influence gonad development and thus sexual maturation in both female and male Aiptasia pallida anemones. This finding substantiates and expands our current understanding of the importance of symbionts in the development and physiology of cnidarian hosts.