SARS-CoV-2 serological findings and exposure risk among employees in school and retail after first and second wave COVID-19 pandemic in Oslo, Norway: a cohort study.

OBJECTIVES: The objective was to characterize and compare SARS-CoV-2 serology among Norwegian school employees and retail employees, and describe preventive measures taken at the workplaces. MATERIAL AND METHODS: A cohort of 238 school and retail employees was enrolled to an ambidirectional cohort study after the first COVID-19 pandemic wave. Self-reported exposure history and serum samples were collected at 10 schools and 15 retail stores in Oslo, Norway, sampled at 2 time-points: baseline (May-July 2020); and follow-up (January-March 2021). SARS-CoV-2 antibodies targeting both spike and nucleocapsid were detected by multiplex microsphere-based serological methods. RESULTS: At baseline, 6 enrolled workers (5 in retail) presented with positive SARS-CoV-2 serology, higher than the expected 1% prevalence (3%, 95% CI: 1-6, p = 0.019). At followup, school and retail groups presented 11 new seropositive cases altogether, but groups were not significantly different, although exposure and preventive measures against viral transmission at workplaces were different between groups. Self-reported medical history of COVID-19 infection showed that all but one positive SARS-CoV-2 serological findings arising between baseline and follow-up had been diagnosed with virus testing. CONCLUSIONS: Distribution of SARS-CoV-2 positive serology after the first wave was slightly higher than expected. Distribution of infection was not significantly different between the groups at baseline nor at follow-up, despite difference in exposure and protective measures. Nearly all new seropositive cases discovered between baseline and follow-up, had already been diagnosed, highlighting the importance of extensive viral testing among workers. Int J Occup Med Environ Health. 2022;35(5):537-47.

Diminished Cold Avoidance Behaviours after Chronic Cold Exposure - Potential Involvement of TRPM8.

Ambient temperature changes trigger plastic biological responses. Cold temperature is detected by the somatosensory system and evokes perception of cold together with adaptive physiological responses. We addressed whether chronic cold exposure induces adaptive adjustments of (1) thermosensory behaviours, and (2) the principle molecular cold sensor in the transduction machinery, transient receptor potential melastatin subtype 8 (TRPM8). Mice in two groups were exposed to either cold (6 °C) or thermoneutral (27 °C) ambient temperatures for 4 weeks and subjected to thermosensory behavioural testing. Cold group mice behaved different from Thermoneutral group in the Thermal Gradient Test: the former occupied a wider temperature range and was less cold avoidant. Furthermore, subcutaneous injection of the TRPM8 agonist icilin, enhanced cold avoidance in both groups in the Thermal Gradient Test, but Cold group mice were significantly less affected by icilin. Primary sensory neuron soma are located in dorsal root ganglia (DRGs), and western blotting showed diminished TRPM8 levels in DRGs of Cold group mice, as compared to the Thermoneutral group. We conclude that acclimation to chronic cold altered thermosensory behaviours, so that mice appeared less cold sensitive, and potentially, TRPM8 is involved.

Repeated social defeat promotes persistent inflammatory changes in splenic myeloid cells; decreased expression of ß-arrestin-2 (ARRB2) and increased expression of interleukin-6 (IL-6).

BACKGROUND: Previous studies suggest that persistent exposure to social stress in mammals may be associated with multiple physiological effects. Here, we examine the effects of social stress in rats, i.e. repeated social defeat, on behavior, hypothalamic-pituitary-adrenal (HPA)-axis and immune system. METHODS: A resident-intruder paradigm, where an intruder rat was exposed to social stress by a dominant resident rat for 1 hour each day for 7 consecutive days was used. The day after the last stress exposure in the paradigm the data were analyzed. Variation in social interaction was observed manually, whereas locomotion was analyzed off-line by a purpose-made software. Gene expression in the pituitary gland, adrenal gland and myeloid cells isolated from the spleen was measured by qPCR. RESULTS: The exposure to social stress induced decreased weight gain and increased locomotion. An increased nuclear receptor subfamily group C number 1 (NR3C1) expression in the pituitary gland was also shown. In myeloid cells harvested from the spleen, we observed decreased expression of the ß2-adrenergic receptor (ADRB2) and ß-arrestin-2 (ARRB2), but increased expression of interleukin-6 (IL-6). Subsequent analyses in the same cells showed that ARRB2 was negatively correlated with IL-6 following the stress exposure. CONCLUSION: Our results show that that the experience of social stress in the form of repeated social defeat in rats is a potent stressor that in myeloid cells in the spleen promotes persistent inflammatory changes. Future research is needed to examine whether similar inflammatory changes also can explain the impact of social stress, such as bullying and harassment, among humans.

Exposure to workplace bullying, microRNAs and pain; evidence of a moderating effect of miR-30c rs928508 and miR-223 rs3848900.

Prolonged exposure to bullying behaviors may give rise to symptoms such as anxiety, depression and chronic pain. Earlier data suggest that these symptoms often are associated with stress-induced low-grade systemic inflammation. Here, using data from both animals and humans, we examined the moderating role of microRNAs (miRNAs, miRs) in this process. In the present study, a resident-intruder paradigm, blood samples, tissue harvesting and subsequent qPCR analyses were used to screen for stress-induced changes in circulating miRNAs in rats. The negative acts questionnaire (NAQ), TaqMan assays and a numeric rating scale (NRS) for pain intensity were then used to examine the associations among bullying behaviors, relevant miRNA polymorphisms and pain in a probability sample of 996 Norwegian employees. In rats, inhibited weight gain, reduced pituitary POMC expression, adrenal Nr3c1 mRNA downregulation, as well as increased miR-146a, miR-30c and miR-223 in plasma were observed following 1 week of repeated exposure to social stress. When following up the miRNA findings from the animal study in the human working population, a stronger relationship between NAQ and NRS scores was observed in subjects with the miR-30c GG genotype (rs928508) compared to other subjects. A stronger relationship between NAQ and NRS scores was also seen in men with the miR-223 G genotype (rs3848900) as compared to other men. Our findings show that social stress may induce many physiological changes including changed expression of miRNAs. We conclude that the miR-30c GG genotype in men and women, and the miR-223 G genotype in men, amplify the association between exposure to bullying behaviors and pain.Lay summaryUsing an animal model of social stress, we identified miR-146a, miR-30c and miR-223 as potentially important gene regulatory molecules that may be involved in the stress response. Interestingly, human genotypes affecting the expression of mature miR-30c and miR-223 had a moderating effect on the association between exposure to bullying and pain. Subjects with the miR-30c rs928508 GG genotype had a significantly stronger association between exposure to bullying behaviors and pain than other subjects. The same was observed in men with the miR-223 rs3848900 G genotype, as compared to other men.