Self-Reported Emotion Regulation Is Associated With Response to Test of Cardiac Vagal Function

Parasympathetic function and emotional self-regulation (ESR) share neuroanatomic structures. Based on Porges’ Polyvagal Theory and the Neurovisceral Integration Model (NIM), we compared vagally mediated heart-rate variability (vmHRV) with psychometrically assessed ESR. We hypothesized that vmHRV and ESR would be associated during rest, a vagal function test, and recovery from that test. A significant association would justify the psychometric measuring of parasympathetic health, which is less burdensome than its psychophysiological assessment. Two hundred thirteen healthy males (aged: 18–26 years, M = 20.29 years) took part in the present study. They completed the Emotion Regulation Questionnaire (ERQ) and underwent the Cold Face Test (CFT) for 4 min wearing ambulatory electrocardiograms. A High frequency (HF) band was used as a measure of vmHRV before, during, and after the CFT. Associations between the HF band and ESR were analyzed with partial rank correlations. There was no significant association between ERQ scores and the response to the CFT itself. But there was an almost significant association between the ERQ scale Cognitive Appraisal and baseline vmHRV, and a significant association between Cognitive Appraisal and cardiac recovery from the CFT, that is, participants with higher scores on that ESR scale revealed a tendency to exhibit greater vmHRV during baseline and they exhibited greater vagal withdrawal during recovery from the CFT. Cognitive appraisal as a psychometrically assessed emotion regulatory process was reflected in a more flexible parasympathetic activity (i.e., better cardiac vagal health) during recovery from an exclusively physiological stressor. This lends convergent validity to self-reported emotion regulation, and justification for its use as a measure of ESR as a trait, offering further support for the Polyvagal Theory and NIM.

THE DIFFERENCES IN RESPONSE TO ACUTE STRESS OF INDIVIDUALS WITH HIGHER AND LOWER NEUROTICISM

"Although some studies analyze neuroticism's role in individuals' response to acute stress, the results are controversial. There is a lack of studies examining the response to stressors of individuals with higher and lower neuroticism in all phases (during the period of anticipation of the stressor, at the time of exposure to the stressor, and during the recovery period after exposure to a stressor), measuring different physiological parameters and evaluating emotional response to a stressor at the same time. This study aimed to assess individuals with higher and lower neuroticism physiological and emotional responses to acute stress. 168 students participated in a study (23 males and 145 females). Their response to 4 different stressors (1 physical and 3 psychological (with standard instruction, the pressure to compete and critique) was evaluated, measuring the changes in their skin conductance, skin temperature, heart rate, respiratory rate while waiting for the stressor (anticipation phase), during the stressor and in the stress recovery phase. The changes in students ‘emotional responses were also measured using the C.R. Carlson et al. (1989) Emotional Assessment Scale (EAS). Students’ neuroticism was assessed using the NEO Five-Factor Inventory's neuroticism subscale (NEO-FFI, Costa, McCrae, 1992). The study results showed that students having higher and lower neuroticism differed when reacting to a physiological stressor. Students' responses to a psychological stressor differed only in the condition when they were criticized."

Human adaptation to hypoxia in critical illness

The syndrome of critical illness is a complex physiological stressor that can be triggered by diverse pathologies. It is widely believed that organ dysfunction and death result from bioenergetic failure caused by inadequate cellular oxygen supply. Teleologically, life has evolved to survive in the face of stressors by undergoing a suite of adaptive changes. Adaptation not only comprises alterations in systemic physiology but also involves molecular reprogramming within cells. The concept of cellular adaptation in critically ill patients is a matter of contention in part because medical interventions mask underlying physiology, creating the artificial construct of “chronic critical illness,” without which death would be imminent. Thus far, the intensive care armamentarium has not targeted cellular metabolism to preserve a temporary equilibrium but instead attempts to normalize global oxygen and substrate delivery. Here, we review adaptations to hypoxia that have been demonstrated in cellular models and in human conditions associated with hypoxia, including the hypobaric hypoxia of high altitude, the intrauterine low-oxygen environment, and adult myocardial hibernation. Common features include upregulation of glycolytic ATP production, enhancement of respiratory efficiency, downregulation of mitochondrial density, and suppression of energy-consuming processes. We argue that these innate cellular adaptations to hypoxia represent potential avenues for intervention that have thus far remained untapped by intensive care medicine.

IRF2 maintains the stemness of colonic stem cells by limiting physiological stress from interferon

The physiological stresses that diminish tissue stem-cell characteristics remain largely unknown. We previously reported that type I interferon (IFN), which is essential for host antiviral responses, is a physiological stressor for hematopoietic stem cells (HSCs) and small intestinal stem cells (ISCs) and that interferon regulatory factor-2 (IRF2), which attenuates IFN signaling, maintains their stemness. Here, using a dextran sodium sulfate (DSS)-induced colitis model, we explore the role of IRF2 in maintaining colonic epithelial stem cells (CoSCs). In mice with a conditional Irf2 deletion in the intestinal epithelium (hereafter Irf2ΔIEC mice), both the number and the organoid-forming potential of CoSCs were markedly reduced. Consistent with this finding, the ability of Irf2ΔIEC mice to regenerate colon epithelium after inducing colitis was severely impaired, independently of microbial dysbiosis. Mechanistically, CoSCs differentiated prematurely into transit-amplifying (TA) cells in Irf2ΔIEC mice, which might explain their low CoSC counts. A similar phenotype was induced in wild-type mice by repeated injections of low doses of poly(I:C), which induces type I IFN. Collectively, we demonstrated that chronic IFN signaling physiologically stresses CoSCs. This study provides new insight into the development of colitis and molecular mechanisms that maintain functional CoSCs throughout life.

0233 Pain, Fatigue, and Altered Reactivity to a Repeated Physiological Stressor in Insomnia Patients: An Explanatory-Driven Analysis

Introduction Fatigue and pain are prominent features of functional impairment in insomnia. This study aimed to better understand behavioral and physiological mechanisms of these complex relationships. Methods 22 participants with insomnia disorder (DSM-5 criteria, 18 female, age 18-49yrs) and 22 good-sleeper controls (19 female, age 18-47yrs) completed two-weeks sleep logs and actigraphy recordings prior to coming to the laboratory for overnight polysomnography and subsequent daytime testing that included questionnaires, three trials of cold pressor test (CPT), and pain testing with blood draws collected throughout. Insomnia diagnosis was determined by a board-certified sleep specialist, and exclusion criteria included psychiatric history within past 6 months, other sleep disorder, significant medical conditions, and any medications within past two weeks with significant effects on inflammation, autonomic function, or other psychotropic effects. For CPT, participants were instructed to immerse hand in ice cold water for at least one minute and rate pain intensity throughout the immersion and 3-minute recovery. Data were analyzed with linear mixed models. Results Per inclusion criteria, PSQI scores were differed between groups (insomnia: 10.2±2.7, range 7–16; control: 1.9±1.3, range 0–5; p<.001). Insomnia consistently reported higher daily fatigue ratings compared to controls (p<.001), as well as higher spontaneous pain globally and across several specific domains (p’s: .007-.03). In response to CPT, groups did not differ in their initial tolerance (i.e. immersion duration, p=.41) or intensity ratings during immersion (p=.88), however insomnia showed blunted recovery in intensity ratings (p<.01). Control participants then showed an ability to habituate to repeated CPT by increasing immersion duration, whereas insomnia slightly decreased in tolerance across trials (Group effect: p<.05). Conclusion These data indicate that habituation to and acute recovery from pain is deteriorated in chronic insomnia, which may be a key contributor to maintained pathophysiology over time and mechanism to target with comprehensive treatment. Support Merck Inc. MISP# 51971 (investigator-initiated), NIH/National Center for Research Resources UL1-RR02758 and M01-RR01032 to the Harvard Clinical and Translational Science Center.

Hand-held Colorimetry Sensor Platform for Determining Salivary α-Amylase Activity and Its Applications for Stress Assessment

This study develops a hand-held stress assessment meter with a chemically colorimetric strip for determining salivary α-amylase activity, using a 3,5 dinitrosalicylic acid (DNS) assay to quantify the reducing sugar released from soluble starch via α-amylase hydrolysis. The colorimetric reaction is produced by heating the strip with a mini polyester heater plate at boiling temperature to form a brick red colored product, which measured at 525 nm wavelength. This investigation describes in detail the design, construction, and performance evaluation of a hand-held α-amylase activity colorimeter with a light emitted diode (LED) and photo-detector with built-in filters. The dimensions and mass of the proposed prototype are only 120 × 60 × 60 mm3 and 200 g, respectively. This prototype has an excellent correlation coefficient (>0.995), comparable with a commercial ultraviolet–visible spectroscope, and has a measurable α-amylase activity range of 0.1–1.0 U mL−1. The hand-held device can measure the salivary α-amylase activity with only 5 μL of saliva within 12 min of testing. This sensor platform effectively demonstrates that the level of salivary α-amylase activity increases more significantly than serum cortisol, the other physiological stressor biomarker, under physiologically stressful exercise conditions. Thus, this work demonstrates that the hand-held α-amylase activity meter is an easy to use and cost-effective stress assessment tool for psychoneuroendocrinology research.