Publications

BACKGROUND/OBJECTIVES: Obesity is associated with unhealthy food choices. Food selection is driven by the subjective valuation of available options, and the perceived and actual rewards accompanying consumption. These cognitive operations are mediated by brain regions including the ventromedial prefrontal cortex (vmPFC), dorsal anterior cingulate cortex (dACC), and ventral striatum (vStr). This study investigated the relationship between body mass index (BMI) and functional activations in the vmPFC, dACC, and vStr during food selection and consumption.

SUBJECTS/METHODS: After overnight fasting, 26 individuals (BMI: 18-40 kg/m2) performed a food choice task while being scanned with functional magnetic resonance imaging (fMRI). Each trial involved selecting one beverage from a pair of presented options, followed by delivery of a 3 mL aliquot of the selected option using an MR-compatible gustometer. We also tracked subjective preference for each beverage throughout the experiment.

RESULTS: During food choice, individuals with greater BMI had less activation in the dorsolateral prefrontal cortex when selecting a high-value option and less vmPFC activation upon its consumption. Independent of BMI, during food choice the dACC and anterior insula elicited higher activation when a less preferred beverage was selected. Activation of the dACC and a broader frontoparietal network was also observed when deciding between options more similar in value. During consumption, receipt of a more preferred beverage was associated with greater vmPFC response, and attenuation of the dACC.

CONCLUSIONS: An individual's preference for a food option modulates the brain activity associated with choosing and consuming it. The relationship between food preference and underlying brain activity is altered in obesity, with reduced engagement of cognition-related regions when presented with a highly valued option, but a blunted response in reward-related regions upon consumption.

BACKGROUND/OBJECTIVES: Obesity is associated with unhealthy food choices. Food selection is driven by the subjective valuation of available options, and the perceived and actual rewards accompanying consumption. These cognitive operations are mediated by brain regions including the ventromedial prefrontal cortex (vmPFC), dorsal anterior cingulate cortex (dACC), and ventral striatum (vStr). This study investigated the relationship between body mass index (BMI) and functional activations in the vmPFC, dACC, and vStr during food selection and consumption.

SUBJECTS/METHODS: After overnight fasting, 26 individuals (BMI: 18-40 kg/m2) performed a food choice task while being scanned with functional magnetic resonance imaging (fMRI). Each trial involved selecting one beverage from a pair of presented options, followed by delivery of a 3 mL aliquot of the selected option using an MR-compatible gustometer. We also tracked subjective preference for each beverage throughout the experiment.

RESULTS: During food choice, individuals with greater BMI had less activation in the dorsolateral prefrontal cortex when selecting a high-value option and less vmPFC activation upon its consumption. Independent of BMI, during food choice the dACC and anterior insula elicited higher activation when a less preferred beverage was selected. Activation of the dACC and a broader frontoparietal network was also observed when deciding between options more similar in value. During consumption, receipt of a more preferred beverage was associated with greater vmPFC response, and attenuation of the dACC.

CONCLUSIONS: An individual's preference for a food option modulates the brain activity associated with choosing and consuming it. The relationship between food preference and underlying brain activity is altered in obesity, with reduced engagement of cognition-related regions when presented with a highly valued option, but a blunted response in reward-related regions upon consumption.

STUDY OBJECTIVES: Sleep is a prominent behavioral and biochemical state observed in all animals studied, including platyhelminth flatworms. Investigations into the biochemical mechanisms associated with sleep-and wakefulness-are important for understanding how these states are regulated and how that regulation changed with the evolution of new types of animals. Unfortunately, beyond a handful of vertebrates, such studies on invertebrates are rare.

METHODS: We investigated the effect of seven neurotransmitters, and one pharmacological compound, that modulate either sleep or wakefulness in mammals, on flatworms (Girardia tigrina). Flatworms were exposed via ingestion and diffusion to four neurotransmitters that promote wakefulness in vertebrates (acetylcholine, dopamine, glutamate, histamine), and three that induce sleep (adenosine, GABA, serotonin) along with the H1 histamine receptor antagonist pyrilamine. Compounds were administered over concentrations spanning three to five orders of magnitude. Flatworms were then transferred to fresh water and video recorded for analysis.

RESULTS: Dopamine and histamine decreased the time spent inactive and increased distance traveled, consistent with their wake-promoting effect in vertebrates and fruit flies; pyrilamine increased restfulness and GABA showed a nonsignificant trend towards promoting restfulness in a dose-dependent manner, in agreement with their sleep-inducing effect in vertebrates, fruit flies, and Hydra. Similar to Hydra, acetylcholine, glutamate, and serotonin, but also adenosine, had no apparent effect on flatworm behavior.

CONCLUSIONS: These data demonstrate the potential of neurotransmitters to regulate sleep and wakefulness in flatworms and highlight the conserved action of some neurotransmitters across species.

STUDY DESIGN: Prospective observational cohort study.

OBJECTIVES: First, describe pressure injury (PI) and associated risk factors in individuals with spinal cord injury/disorder (SCI/D) during first rehabilitation. Second, evaluate a prediction model for hospital acquired PI (HAPI) development.

SETTING: Acute care and rehabilitation clinic specialized in SCI/D.

METHODS: Patients ≥18 years of age with SCI/D were included during first rehabilitation between 08/2018 and 12/2019. We performed a systematic literature search to identify risk factors for PI development. Patients were classified according to HAPI developed. Between group differences of patients' characteristics and risk factors were analyzed using descriptive statistics. Logistic predictive models were performed to estimate HAPI development and receiver operator characteristic (ROC) curve was used to test the model.

RESULTS: In total, 94 patients were included, 48 (51.1%) developed at least one HAPI and in total 93 were observed, mainly stage I and stage II HAPI according to the European Pressure Ulcer Advisory Panel. We found nine significantly associated risk factors: completeness of SCI/D, pneumonia, sedative medications, autonomic dysreflexia, Braden ≤12 points, SCIPUS ≥9 points, lower admission SCIM and lower admission FIM-cognition, longer length of stay (LOS) (p ≤ 0.0005). In a predictive model, none of the risk factors was associated with HAPI development (AUC = 0.5).

CONCLUSION: HAPIs in patients with SCI/D during first rehabilitation are a frequent and complex condition and associated with several risk factors. No predictive model exists but with the identified risk factors of this study, larger studies can create a tailored and flexible HAPI risk prediction model.

While studies suggest that light and feeding patterns can reset circadian rhythms in various metabolites, whether these shifts follow a predictable pattern is unknown. We describe the first phase response curves (PRC) for lipids and hepatic proteins in response to combined light and food stimuli. The timing of plasma rhythms was assessed by constant routine before and after exposure to a combined 6.5-hour blue light exposure and standard meal schedule, which was systematically varied by  20° between in0000dividuals. We find that the rhythms shift according to a PRC, with generally greater shifts for lipids and liver proteins than for melatonin. PRC timing varies relative to the stimulus, with albumin and triglyceride PRCs peaking at a time similar to melatonin whereas the cholesterol and high-density lipoprotein PRCs are offset by  12 h. These data have important implications for treating circadian misalignment in shiftworkers who consume meals and are exposed to light around the clock.

BACKGROUND: Previous work implicates high pro-inflammatory biomarkers in mood disturbance and low brain-derived neurotrophic factor (BDNF) levels in major depression. However, in hormonally-sensitive premenstrual dysphoric disorder (PMDD), BDNF levels are higher when mood is worse. Perimenopausal depression has not been studied to date. We evaluated whether BDNF and inflammatory cytokines predict mood symptoms across the menstrual cycle in hormonally-sensitive perimenopausal depression symptoms.

METHODS: Data from 49 time points derived from mid-to-late follicular phase [M/L-FP] and peri‑menstrual assessments of 14 perimenopausal women ages 38-52 with ovulatory menstrual cycles 24-35 days long across 1-2 cycles for mood symptoms, BDNF levels, cytokines, gonadal steroids. Depression was assessed with Montgomery-Åsberg Depression Rating Scale (MADRS), Beck Depression Inventory (BDI); irritability with Kellner Symptom Questionnaire Anger-Hostility subscale (SQ); overall psychological distress with Profile of Mood States (POMS). Mixed models were run on dependent measures of MADRS (primary endpoint) and other mood outcomes (BDI, POMS, SQ) with independent variables of interest (each biomarker, cycle phase), controlling for cycle number and participant.

RESULTS: After FDR adjustment, BDNF levels showed consistent significant positive relationships to MADRS (β=0.00053; p = 0.0028), POMS (β=0.00153; p = 0.0394), SQ (β=0.00053; p = 0.0067), and BDI (β=0.00039; p = 0.0231). Cycle phase did not affect this relationship. No other biomarker consistently predicted affective symptom severity.

LIMITATIONS: Small sample size and large number of comparisons.

CONCLUSION: In women with perimenopausal depression symptoms, BDNF is elevated in association with more severe mood symptomatology, resembling the pattern in hormonally-sensitive PMDD and suggesting a hormonally-sensitive mood disorder biomarker profile distinct from that of major depression.

STUDY OBJECTIVES: The neuropeptide orexin promotes wakefulness, modulates thermoregulation, increases after menopause, and is normalized in women receiving estrogen therapy, suggesting a role for orexin antagonism as a treatment for the vasomotor symptom (VMS)-associated insomnia disorder. We tested the efficacy of the dual orexin receptor antagonist suvorexant for chronic insomnia related to nighttime VMS.

METHODS: In a double-blind, placebo-controlled trial, 56 women with chronic insomnia associated with nighttime VMS, Insomnia Severity Index (ISI) scores ≥15, and >30 min of diary-rated wake after sleep-onset (WASO) were randomized to receive oral suvorexant 10-20 mg (n = 27) or placebo (n = 29) nightly for 4 weeks. Analysis of within-person change in ISI was adjusted for baseline ISI and race.

RESULTS: Mean baseline ISI scores were 18.1 (95% CI, 16.8 to 19.4) and 18.3 (95% CI, 17.2 to 19.5) in the suvorexant and placebo groups, respectively (p = .81). The average 4-week ISI within-person decrease from baseline was greater on suvorexant (-8.1 [95% CI, -10.2 to -6.0]) compared to placebo (-5.6 [95% CI, -7.4 to -3.9], p = .04). Compared to placebo, nighttime diary-rated VMS frequency was significantly reduced with suvorexant (p < .01). While diary-rated WASO and total sleep time trended toward improvement on suvorexant, findings were not significant after adjustment for multiple comparisons. Daytime VMS and other sleep-related outcomes did not differ between groups. Suvorexant was well tolerated.

CONCLUSION: These results suggest that suvorexant is likely a well-tolerated and efficacious treatment for VMS-associated insomnia disorder and reduces nighttime VMS. Antagonism of orexin receptors could provide a novel therapeutic option for midlife women with VMS-associated chronic insomnia.

CLINICAL TRIAL INFORMATION: Efficacy of Suvorexant in the Treatment of Hot Flash-associated Insomnia, https://clinicaltrials.gov/ct2/show/NCT03034018, ClinicalTrials.gov Identifier: NCT03034018.

BACKGROUND: Historically, females have been underrepresented in clinical trials evaluating the safety and efficacy of investigational drugs and devices. We assessed participation by sex in recent clinical trials.

METHODS: We extracted data over a 4-year period (2016-2019) from ClinicalTrials.gov on US-based, pharmaceutical industry or government-funded Phase 1-3 clinical trials of drugs and devices. We included trials with adult cardiovascular, psychiatric, and cancer endpoints whose protocol planned to enroll both sexes. Average proportions of females enrolled per trial were described overall and by disease area.

RESULTS: Across 1433 trials including 302,664 participants in our analysis, on average, 41.2% were female. Females were underrepresented compared with their proportion of the disease population in cardiovascular disease trials (41.9% female participants vs. 49% female population with cardiovascular disease). In psychiatry, where females comprise 60% of patients, the mean participation of females in clinical trials was 42.0%. Similarly, for cancer trials, where 51% of patients are female, only 41.0% of cancer clinical trial participants were female. For each therapeutic area analyzed, the participation of females in clinical trials fell short of the benchmark derived from national prevalence data.

CONCLUSIONS: While the participation of females in clinical trials has improved compared to previous reports, sex-based gaps still persist between trial populations and those expected to use these drugs/devices based on distributions of diseases in the population. Given potential sex-based differences in treatment responses and toxicities, adequate inclusion of females in clinical trials remains critical.

The daily rhythm of plasma melatonin concentrations is typically unimodal, with one broad peak during the circadian night and near-undetectable levels during the circadian day. Light at night acutely suppresses melatonin secretion and phase shifts its endogenous circadian rhythm. In contrast, exposure to darkness during the circadian day has not generally been reported to increase circulating melatonin concentrations acutely. Here, in a highly-controlled simulated night shift protocol with 12-h inverted behavioral/environmental cycles, we unexpectedly found that circulating melatonin levels were significantly increased during daytime sleep (p < .0001). This resulted in a secondary melatonin peak during the circadian day in addition to the primary peak during the circadian night, when sleep occurred during the circadian day following an overnight shift. This distinctive diurnal melatonin rhythm with antiphasic peaks could not be readily anticipated from the behavioral/environmental factors in the protocol (e.g., light exposure, posture, diet, activity) or from current mathematical model simulations of circadian pacemaker output. The observation, therefore, challenges our current understanding of underlying physiological mechanisms that regulate melatonin secretion. Interestingly, the increase in melatonin concentration observed during daytime sleep was positively correlated with the change in timing of melatonin nighttime peak (p = .002), but not with the degree of light-induced melatonin suppression during nighttime wakefulness (p = .92). Both the increase in daytime melatonin concentrations and the change in the timing of the nighttime peak became larger after repeated exposure to simulated night shifts (p = .002 and p = .006, respectively). Furthermore, we found that melatonin secretion during daytime sleep was positively associated with an increase in 24-h glucose and insulin levels during the night shift protocol (p = .014 and p = .027, respectively). Future studies are needed to elucidate the key factor(s) driving the unexpected daytime melatonin secretion and the melatonin rhythm with antiphasic peaks during shifted sleep/wake schedules, the underlying mechanisms of their relationship with glucose metabolism, and the relevance for diabetes risk among shift workers.