A Randomized Phase 1 Evaluation of Deupirfenidone, a Novel Deuterium-Containing Drug Candidate for Interstitial Lung Disease and Other Inflammatory and Fibrotic Diseases.

LYT-100 (deupirfenidone) is a selectively deuterated form of pirfenidone under development for the treatment of inflammatory and fibrotic diseases, including interstitial lung disease. Adverse events associated with antifibrotics can be a barrier to adoption and persistence in patients with interstitial lung diseases, most of whom are not on standard-of-care therapy. LYT-100 is designed to have a differentiated pharmacokinetic (PK) profile from pirfenidone and could offer a differentiated safety profile compared to current standard-of-care drugs while retaining the biochemical potency and specificity of pirfenidone. We conducted a phase 1b study to ascertain the safety, tolerability, steady-state PK profile, and food effect of LYT-100. This was a 2-part study. Part 1 assessed multiple ascending doses of LYT-100 from 100, 250, 500, 750, and 1000 mg twice daily given over 5 days without titration. Part 2 assessed the effects of fed vs fasting conditions on the PK profile of a single 500-mg dose of LYT-100. All doses up to 1000 mg were well tolerated, with adverse events being mild and transient. Exposure was slightly lower in the fed condition. LYT-100 was well tolerated and has a dose-proportional PK profile. The ratio of parent to major metabolite concentration was higher than reported with pirfenidone, which is consistent with an effect of deuteration on metabolism. No maximum tolerated dose was identified up to 1000 mg twice-daily dosing. These results support further clinical development of LYT-100, particularly considering the adverse event profile of current standard-of-care drugs.

Characteristics Associated With New Patient Appointment No-Shows at an Academic Ophthalmology Department in the United States.

PURPOSE: This study aimed to identify patient and appointment characteristics associated with no-shows to new patient appointments at a US academic ophthalmology department. DESIGN: Cross-sectional study. METHODS: This was a study of all adult patients with new patient appointments scheduled with an attending ophthalmologist at Penn State Eye Center between January 1st and December 31st of 2019. A multiple logistic regression model was used to assess the association between characteristics and no-show status. RESULTS: Of 4,628 patients, 759 (16.4%) were no-shows. From the multiple logistic regression model, characteristics associated with no-shows were age (Odds Ratio (OR) for 18-40 years vs. >60 years: 3.41, 95% Confidence Interval (CI) 2.57, 4.51, p <0.001 and OR for 41-60 years vs. >60 years: 2.14, 95% CI 1.67, 2.74, p<0.001), median household income (OR for <$35,667 vs. >$59,445: 1.59, 95% CI 1.08, 2.34, p<0.001), insurance (OR for None vs. Medicare: 6.92, 95% CI 4.41, 10.86, p<0.001 and OR for Medicaid vs. Medicare: 1.54, 95% CI 1.18, 2.01, p=0.002), race (OR for Black vs. White: 2.62, 95% CI 2.00, 3.43, p<0.001 and OR for Other vs. White: 2.02, 95% CI 1.58, 2.59, p<0.001), and commute distance (OR for 5-10 mi vs. ≤5 mi: 1.73, 95% CI 1.17, 2.55, p=0.006). Appointments with longer lead times and scheduled with glaucoma or retina specialists were also significantly associated with greater no-shows. CONCLUSION: Certain patient and appointment characteristics were associated with no-show status. These findings may assist in the development of targeted interventions at the patient, practice, and health system levels to improve appointment attendance.

Sex Differences in Academic Rank, Scholarly Productivity, National Institutes of Health Funding, and Industry Ties Among Academic Cornea Specialists in the United States.

PURPOSE: This study analyzed sex differences among cornea specialists with regards to academic rank, scholarly productivity, National Institutes of Health (NIH) funding, and industry partnerships. DESIGN: Cross-sectional study. METHODS: This was a study of faculty at 113 US academic programs. Sex, residency graduation year, and academic rank were collected from institutional websites between January and March 2019. H-indices and m-quotients were collected from the Scopus database. The NIH Research Portfolio Online Reporting Tool and Centers for Medicare and Medicaid Services databases were queried for data on NIH funding and industry partnerships. RESULTS: Of the 440 cornea specialists identified, 131 (29.8%) were female. The proportions of females and males at each academic rank (assistant 69.5% vs 41.8%; associate 17.6% vs 21.0%; full professor 13.0% vs 37.2%) were not significant after adjusting for career duration (P = .083, .459, and .113, respectively). Females had significantly lower median h-indices (4.0 [interquartile range {IQR} 7.0] vs 11.0 [IQR 17.0], P < .001) and shorter median career duration (12.0 [IQR 11.0] vs. 25.0 [IQR 20.0] years, P < .001) than males but similar median m-quotients (0.5 [IQR 0.8] vs 0.5 [IQR 0.8], P = 1.00). Sex differences in h-indices were not seen at each academic rank or career duration interval. Among NIH-funded investigators, the median grant funding was $1.6M (IQR $2.2M) for females and $1.2M (IQR $4.6M, P = .853) for males. Overall, 25.5% of females and 58.6% of males (P = .600) had industry partnerships. CONCLUSION: Sex differences within academic ranks and h-indices are likely due to a smaller proportion of females with advanced career duration.

Neoadjuvant Leuprolide Therapy with Radical Prostatectomy: Long-term Effects on Health-related Quality of Life.

BACKGROUND: Neoadjuvant androgen ablation (neoadjuvant androgen deprivation therapy [NADT]) is used prior to radical prostatectomy, contrary to guidelines, but its long-term effects on quality of life is unknown. OBJECTIVE: To determine the effect of NADT on patient's long-term recovery following surgery. DESIGN, SETTING, AND PARTICIPANTS: From March 2011 to August 2013, 5808 men with newly diagnosed prostate were followed up to 24 mo. A cohort of men who received NADT prior to robotic-assisted laparoscopic prostatectomy (RALP; n=51) was compared 1:3 with a matched group that underwent RALP only (n=153). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Patients were matched on Charlson comorbidities, biopsy Gleason score, and node status on final pathology. The Kruskall-Wallis test was used to compare the groups on their bowel, urinary, sexual, and hormonal domains of the 26-item Expanded Prostate Cancer Index Composite at baseline and at 1, 3, 6, 12, 18, and 24 mo postoperatively. RESULTS AND LIMITATIONS: The urinary irritative, urinary incontinence, and bowel domains were similar in the two groups during the 24 mo (p=0.832, 0.901, and 0.732, respectively). In the hormonal domain, the NADT group did worse (p<0.001). The sexual domain was also worse for the NADT group. However, when accounting for nerve sparing, there was no significant difference in sexual outcomes between the two groups (p=0.069). CONCLUSIONS: Patients who received NADT prior to RALP do not have worse sexual function, but have worse hormonal scores for up to 2yr after surgery. PATIENT SUMMARY: Neoadjuvant androgen deprivation therapy (NADT) is administered prior to robotic-assisted laparoscopic prostatectomy (RALP), contrary to clinical guidelines. NADT may not have worse sexual function outcomes up to 2yr after RALP.

Physician Compliance to Choosing Wisely® Initiative in Radiographic Imaging of Low Risk Prostate Cancer in an Integrated Health Care System.

INTRODUCTION: We evaluated the adherence of urologists within an integrated health care system to Choosing Wisely®, an initiative aimed at avoiding unnecessary medical tests. In urology, 2 of the guidelines state bone scans and pelvic computerized tomography scans are unnecessary in low risk prostate cancer. METHODS: We performed a retrospective study on patients diagnosed with low risk prostate cancer between January 1, 2010 and December 31, 2017 at Kaiser Permanente Southern California. All demographics and imaging data were obtained. Patients with symptoms concerning for metastatic disease or with other malignancies were excluded by chart review. Statistical analysis was employed to compare the use of bone scans and computerized tomography scans in this population before and after the Choosing Wisely guidelines were published. RESULTS: Of the 6,996 patients, 121 (1.7%) and 96 (1.4%) underwent a bone scan and computerized tomography scan, respectively. A Cochran-Armitage test showed no change after implementation of the statements. Logistic regression analysis revealed that for every point increase in prostate specific antigen, the odds ratio was 1.09 for ordering both a bone scan and computerized tomography scan. When compared to Whites, the odds ratio of having a bone scan and computerized tomography scan were 0.35 and 0.37 for Blacks, 0.30 and 0.38 for Hispanics, and 0.47 and 0.61 for Asians, respectively. CONCLUSIONS: Over the study period, there were low rates of inappropriate imaging for low risk prostate cancer. There was no change in trend after publication of the Choosing Wisely. Higher prostate specific antigen levels and White ethnicity were predictors for ordering inappropriate imaging.

A Layered Control Architecture of Sleep and Arousal.

Sleep and wakefulness are promoted not by a single neural pathway but via wake or sleep-promoting nodes distributed across layers of the brain. We equate each layer with a brain region in proposing a layered subsumption model for arousal based on a computational architecture. Beyond the brainstem the layers include the diencephalon (hypothalamus, thalamus), basal ganglia, and cortex. In light of existing empirical evidence, we propose that each layer have sleep and wake computations driven by similar high-level architecture and processing units. Specifically, an interconnected wake-promoting system is suggested as driving arousal in each brain layer with the processing converging to produce the features of wakefulness. In contrast, sleep-promoting GABAergic neurons largely project to and inhibit wake-promoting neurons. We propose a general pattern of caudal wake-promoting and sleep-promoting neurons having a strong effect on overall behavior. However, while rostral brain layers have less influence on sleep and wake, through descending projections, they can subsume the activity of caudal brain layers to promote arousal. The two models presented in this work will suggest computations for the layering and hierarchy. Through dynamic system theory several hypotheses are introduced for the interaction of controllers and systems that correspond to the different populations of neurons at each layer. The models will be drawn-upon to discuss future experiments to elucidate the structure of the hierarchy that exists among the sleep-arousal architecture.

International experiences during United States ophthalmology residency training: Current structure of international experiences and perspectives of faculty mentors at United States training institutions.

BACKGROUND: There is a high level of interest in international experiences during United States (U.S.) ophthalmology residency training among both program directors and trainees. METHODS: An electronic invitation to a 26-question survey was sent to all 114 U.S. ophthalmology residency program directors. The invitation requested that the survey be completed by the one faculty member who was most involved in overseeing the international experiences for the residents. The survey consisted of multiple choice and Likert-type scale questions. The Mann-Whitney U test was used for analysis of demographic data and Friedman's test and Wilcoxon-Signed Rank test were used to analyze ranked responses. RESULTS: Responses were obtained from 70 faculty mentors representing unique programs, yielding a response rate of 61.4%. The majority of programs that responded (88.6%, n = 62) either offered international ophthalmology experiences for residents or supported residents finding their own experiences to go abroad. International experience participation rate among residents correlated with the number of years the experiences had been offered by the programs (p = 0.001). More than half of the respondents (55.0%, n = 33) felt that the residents benefited more than the hosts during these international experiences. Approximately half of the respondents (51.6%, n = 32) believed that additional training beyond what is covered in the standard curriculum to practice ophthalmology in the U.S. is necessary for practicing ophthalmology in an international setting. CONCLUSIONS: There is high interest and participation in international experiences within U.S. ophthalmology residency programs. This high participation warrants further investigation into the long-term impact of these international experiences and how U.S. residency programs can structure these experiences to maximize the benefits to both the residents and the international host communities.

How Should Mission Trips Be Administered?

Opportunities to study and practice health-related professions internationally offer transformative benefits for patients, educators, and students. Institutions and educators should model ethical behavior and set examples for global health trainees. Toward this end, it is imperative that universities engaging in international immersion experiences ensure that principles of respect, beneficence, and justice are upheld.

Nigrostriatal and mesolimbic control of sleep-wake behavior in rat.

The midbrain dopamine system via the dorsal and ventral striatum regulates a wide range of behaviors. To dissect the role of dopaminergic projections to the dorsal striatum (nigrostriatal projection) and ventral striatum (mesolimbic projection) in sleep-wake behavior, we selectively chemogenetically stimulated nigrostriatal or mesolimbic projections and examined the resulting effects on sleep in rats. Stimulation of nigrostriatal pathways increased sleep and EEG delta power, while stimulation of mesolimbic pathways decreased sleep and reduced cortical EEG power. These results indicate that midbrain dopamine signaling in the dorsal or ventral striatum promotes sleep or wake, respectively.

Synergy Testing of Antiamoebic Agents for Acanthamoeba: Antagonistic Effect of Voriconazole.

PURPOSE: To determine whether combinations of commonly used antiamoebic agents display synergy in their ability to kill Acanthamoeba cysts in vitro. METHODS: Synergy testing was performed with a microdilution checkerboard assay on 10 clinical Acanthamoeba keratitis isolates collected at the Proctor Foundation from 2008 to 2012. Each isolate was exposed to pairwise combinations of chlorhexidine, propamidine, and voriconazole. The minimum cysticidal concentration (MCC) for each drug pair was estimated for each isolate, and the summed fractional cysticidal concentration (ΣFCC) was calculated for each drug combination in the checkerboard, with synergy defined as a lack of growth at a ΣFCC ≤ 0.5 and antagonism as growth at a ΣFCC > 4. RESULTS: Chlorhexidine and propamidine were cysticidal, with median MCCs of 12.5 (range 1.5-50) and 11.7 (range 0.2-250), respectively. Voriconazole was not cysticidal, with a median MCC of >10,000 µg/mL. The combination of chlorhexidine and propamidine did not markedly change the cysticidal activity compared with either drug alone. By contrast, voriconazole antagonized the cysticidal activity of both chlorhexidine and propamidine, with Acanthamoeba growth observed at antagonistic ΣFCCs in 27 of 49 (55.1%, 95% confidence interval 35.7%-78.6%) checkerboard combinations of voriconazole and chlorhexidine and in 58 of 147 (39.5%, 95% confidence interval 14.3%-50.3%) combinations of voriconazole and propamidine. CONCLUSIONS: In an in vitro assay, voriconazole reduced the cysticidal activity of 2 commonly used antiamoebic drugs. Although the in vivo drug interactions could be different, these observations may be useful in cases of nonhealing Acanthamoeba keratitis being treated with combination therapies that include voriconazole.

RNA G-quadruplex is resolved by repetitive and ATP-dependent mechanism of DHX36.

DHX36 is a DEAH-box helicase that resolves parallel G-quadruplex structures formed in DNA and RNA. The recent co-crystal structure of DHX36 bound G4-DNA revealed an intimate contact, but did not address the role of ATP hydrolysis in G4 resolving activity. Here, we demonstrate that unlike on G4-DNA, DHX36 displays ATP-independent unfolding of G4-RNA followed by ATP-dependent refolding, generating a highly asymmetric pattern of activity. Interestingly, DHX36 refolds G4-RNA in several steps, reflecting the discrete steps in forming the G4 structure. We show that the ATP-dependent activity of DHX36 arises from the RNA tail rather than the G4. Mutations that perturb G4 contact result in quick dissociation of the protein from RNA upon ATP hydrolysis, while mutations that interfere with binding the RNA tail induce dysregulated activity. We propose that the ATP-dependent activity of DHX36 may be useful for dynamically resolving various G4-RNA structures in cells.

Protein and RNA dynamical fingerprinting.

Protein structural vibrations impact biology by steering the structure to functional intermediate states; enhancing tunneling events; and optimizing energy transfer. Strong water absorption and a broad continuous vibrational density of states have prevented optical identification of these vibrations. Recently spectroscopic signatures that change with functional state were measured using anisotropic terahertz microscopy. The technique however has complex sample positioning requirements and long measurement times, limiting access for the biomolecular community. Here we demonstrate that a simplified system increases spectroscopic structure to dynamically fingerprint biomacromolecules with a factor of 6 reduction in data acquisition time. Using this technique, polarization varying anisotropy terahertz microscopy, we show sensitivity to inhibitor binding and unique vibrational spectra for several proteins and an RNA G-quadruplex. The technique's sensitivity to anisotropic absorbance and birefringence provides rapid assessment of macromolecular dynamics that impact biology.

The National Sleep Foundation's Sleep Satisfaction Tool.

OBJECTIVES: The National Sleep Foundation (NSF) sought to test, refine, and add statistical rigor to its previously described provisional Sleep Satisfaction Tool (SST). The tool assesses the general population's sleep satisfaction. DESIGN: In 2017, NSF created a provisional tool through systematic literature review and an expert consensus panel process. This tool was expanded, refined, and tested through an open-ended survey, 2 rounds of cognitive testing, and a national survey of a random sample of Internet users (aged 18-90). Factor analysis and final consensus panel voting produced the robust SST. RESULTS: The exploratory, open-ended surveying for identifying additional factors important to the public led to question formulation around mind relaxation. Cognitive testing yielded significant refinement to question and response option formatting. Factor analysis of questions from field testing indicated loading on one construct identified as "sleep satisfaction." The final 9-item SST demonstrated strong reliability and internal validity with overall SST scores of 56/100 (higher scores indicating greater sleep satisfaction). Individual SST item mean scores ranged from 39 to 66, and overall SST scores varied substantially across demographic groups. CONCLUSIONS: NSF used a series of development and validation tests on its provisional SST, producing a novel and reliable research tool that measures the general population's sleep satisfaction. The SST is a short, reliable, nonclinical assessment that expands the set of tools available to researchers that implements the individual, social, and environmental factors related to sleep satisfaction. Further research will explore refined scoring methods along with factor weighting and use within different populations.

Structural basis of G-quadruplex unfolding by the DEAH/RHA helicase DHX36.

Guanine-rich nucleic acid sequences challenge the replication, transcription, and translation machinery by spontaneously folding into G-quadruplexes, the unfolding of which requires forces greater than most polymerases can exert1,2. Eukaryotic cells contain numerous helicases that can unfold G-quadruplexes 3 . The molecular basis of the recognition and unfolding of G-quadruplexes by helicases remains poorly understood. DHX36 (also known as RHAU and G4R1), a member of the DEAH/RHA family of helicases, binds both DNA and RNA G-quadruplexes with extremely high affinity4-6, is consistently found bound to G-quadruplexes in cells7,8, and is a major source of G-quadruplex unfolding activity in HeLa cell lysates 6 . DHX36 is a multi-functional helicase that has been implicated in G-quadruplex-mediated transcriptional and post-transcriptional regulation, and is essential for heart development, haematopoiesis, and embryogenesis in mice9-12. Here we report the co-crystal structure of bovine DHX36 bound to a DNA with a G-quadruplex and a 3' single-stranded DNA segment. We show that the N-terminal DHX36-specific motif folds into a DNA-binding-induced α-helix that, together with the OB-fold-like subdomain, selectively binds parallel G-quadruplexes. Comparison with unliganded and ATP-analogue-bound DHX36 structures, together with single-molecule fluorescence resonance energy transfer (FRET) analysis, suggests that G-quadruplex binding alone induces rearrangements of the helicase core; by pulling on the single-stranded DNA tail, these rearrangements drive G-quadruplex unfolding one residue at a time.

Diversity of Chlamydia trachomatis in Trachoma-Hyperendemic Communities Treated With Azithromycin.

Prior studies have theorized that low chlamydial genetic diversity following mass azithromycin treatments for trachoma may create a population bottleneck that prevents the return of infection, but little empirical evidence exists to support this hypothesis. In this study, a single mass azithromycin distribution was administered to 21 communities in the Gurage Zone of Ethiopia in 2003. All children aged 1-5 years had conjunctival swabs performed before treatment and 2 and 6 months after treatment. All swabs positive for Chlamydia trachomatis at 2 months underwent typing of the gene encoding the major outer membrane protein (ompA) of C. trachomatis, as did the same number of swabs per community from the pretreatment and 6-month visits. Diversity of ompA types, expressed as the reciprocal of Simpson's index, was calculated for each community. In total, 15 ompA types belonging to the A and B genovars were identified. The mean diversity was 2.11 (95% confidence interval: 1.79, 2.43) before treatment and 2.16 (95% confidence interval: 1.76, 2.55) 2 months after treatment (P = 0.78, paired t test). Diversity of ompA was not associated with the prevalence of ocular chlamydia (P = 0.76) and did not predict subsequent changes in the prevalence of ocular chlamydia (P = 0.32). This study found no evidence to support the theory that ompA diversity is associated with transmission of ocular chlamydia.

A provisional tool for the measurement of sleep satisfaction.

OBJECTIVES: The goal of this project was to provisionally identify the basic elements of sleep satisfaction within the general population. METHODS: The National Sleep Foundation conducted a systematic literature review and identified 495 published articles evaluating potential indicators of sleep satisfaction. The National Sleep Foundation then convened an expert panel ("Panel"), provided full-text articles and summaries, and used a modified RAND appropriateness method with three total rounds of voting to determine the appropriateness of indicators for sleep satisfaction. RESULTS: The literature review revealed no tools or measures of sleep satisfaction (not dissatisfaction) applied to the general population and directly associated with good health. Nonetheless, a variety of sleep factors were extracted from the extant sleep research literature. Panel members voted on these indicators: sleep environmental factors; and sleep initiation and maintenance parameters. Using these indicators, the Panel constructed provisional questions for measuring sleep satisfaction. CONCLUSIONS: The Panel determined that appropriate sleep satisfaction elements include how an individual feels (a) about their sleep, (b) immediately after their sleep, and (c) during the subsequent day. Additionally, appropriate environmental elements include (a) bedding comfort, (b) bedroom temperature, and (c) noise and light in the bedroom. How one feels with (a) the time it takes to fall asleep, (b) the ease with which one falls back to sleep after awakening during a sleep period, (c) the amount of sleep on weekdays and weekends, as well as how undisturbed one's sleep is also were determined to be appropriate contributors to sleep satisfaction. Finally, the Panel agreed that whether an individual desired to change anything about their sleep, is a relevant question.

Corneal transplantation at Tenwek Hospital, Kenya, East Africa: Analysis of outcomes and associated patient socioeconomic characteristics.

PURPOSE: To review the graft survival rate, visual outcomes, and patient demographics of primary penetrating keratoplasty performed at Tenwek Hospital, a mission hospital in rural Kenya. METHODS: A retrospective review was performed of the clinical records of patients who underwent primary penetrating keratoplasty for optical purposes from January 2012 to October 2014. The graft survival rates were constructed using the Kaplan-Meier method, and the effect of clinical and socioeconomic characteristics on time to graft failure were examined using Cox regression models. RESULTS: 118 patients met the inclusion criteria. The most common indication for surgery was keratoconus (66.1%), followed by corneal scar (22.0%). Despite all patients giving a verbal commitment to do so, 40 patients (33.9%) failed to make it to followup one year postoperatively. Graft survival at one year, inclusive of all indications, was 85.8%. Of the different indications, keratoconus had the highest one-year graft survival rate of 89.9%. Compared to the preoperative uncorrected visual acuity, 85.3% achieved an improvement at one year. Compared to patients who had completed college or university, the risk of developing graft failure was 4.7 times higher among patients with less education (P = 0.01). CONCLUSIONS: Corneal transplantation at Tenwek Hospital can be performed with a reasonable chance of success at one year, particularly in cases of keratoconus and in patients with higher educational backgrounds. Adherence to followup recommendations proves to be a challenge in this patient population. Additional studies of larger patient populations with longer follow up periods in similar settings may be helpful in informing appropriate patient selection and maximizing successful outcomes of corneal transplantation in low-resource settings.

Targeted disruption of supraspinal motor circuitry reveals a distributed network underlying Restless Legs Syndrome (RLS)-like movements in the rat.

In this study we uncovered, through targeted ablation, a potential role for corticospinal, cerebello-rubro-spinal, and hypothalamic A11 dopaminergic systems in the development of restless legs syndrome (RLS)-like movements during sleep. Targeted lesions in select basal ganglia (BG) structures also revealed a major role for nigrostriatal dopamine, the striatum, and the external globus pallidus (GPe) in regulating RLS-like movements, in particular pallidocortical projections from the GPe to the motor cortex. We further showed that pramipexiole, a dopamine agonist used to treat human RLS, reduced RLS-like movements. Taken together, our data show that BG-cortico-spinal, cerebello-rubro-spinal and A11 descending projections all contribute to the suppression of motor activity during sleep and sleep-wake transitions, and that disruption of these circuit nodes produces RLS-like movements. Taken together with findings from recent genomic studies in humans, our findings provide additional support for the concept that the anatomic and genetic etiological bases of RLS are diverse.

Ventral medullary control of rapid eye movement sleep and atonia.

Discrete populations of neurons at multiple levels of the brainstem control rapid eye movement (REM) sleep and the accompanying loss of postural muscle tone, or atonia. The specific contributions of these brainstem cell populations to REM sleep control remains incompletely understood. Here we show in rats that viral vector-based lesions of the ventromedial medulla at a level rostral to the inferior olive (pSOM) produced violent myoclonic twitches and abnormal electromyographic spikes, but not complete loss of tonic atonia, during REM sleep. Motor tone during non-REM (NREM) sleep was unaffected in these same animals. Acute chemogenetic activation of pSOM neurons in rats robustly and selectively suppressed REM sleep but not NREM sleep. Similar lesions targeting the more rostral ventromedial medulla (RVM) did not affect sleep or atonia, while chemogenetic stimulation of the RVM produced wakefulness and reduced sleep. Finally, selective activation of vesicular GABA transporter (VGAT) pSOM neurons in mice produced complete suppression of REM sleep whereas their loss increased EMG spikes during REM sleep. These results reveal a key contribution of the pSOM and specifically the VGAT+ neurons in this region in REM sleep and motor control.

Stimulation of the Pontine Parabrachial Nucleus Promotes Wakefulness via Extra-thalamic Forebrain Circuit Nodes.

Human and animal studies have identified an especially critical role for the brainstem parabrachial (PB) complex in regulating electrocortical (electroencephalogram [EEG]) and behavioral arousal: lesions of the PB complex produce a monotonous high-voltage, slow-wave EEG and eliminate spontaneous behaviors. We report here that targeted chemogenetic activation of the PB complex produces sustained EEG and behavioral arousal in the rat. We further establish, using viral-mediated retrograde activation, that PB projections to the preoptic-basal forebrain and lateral hypothalamus, but not to the thalamus, mediate PB-driven wakefulness. We exploited this novel and noninvasive model of induced wakefulness to explore the EEG and metabolic consequences of extended wakefulness. Repeated (daily) chemogenetic activation of the PB was highly effective in extending wakefulness over 4 days, although subsequent PB activation produced progressively lesser wake amounts. Curiously, no EEG or behavioral sleep rebound was observed, even after 4 days of induced wakefulness. Following the last of the four daily induced wake bouts, we examined the brains and observed a chimeric pattern of c-Fos expression, with c-Fos expressed in subsets of both arousal- and sleep-promoting nuclei. From a metabolic standpoint, induced extended wakefulness significantly reduced body weight and leptin but was without significant effect on cholesterol, triglyceride, or insulin levels, suggesting that high sleep pressure or sleep debt per se does not, as previously implicated, result in a deleterious metabolic phenotype.