Erratum: Role of adipocyte Na,K-ATPase oxidant amplification loop in cognitive decline and neurodegeneration.

[This corrects the article DOI: 10.1016/j.isci.2021.103262.].

Ondansetron Safety Regarding Prolong QTc for Children with Head Trauma.

BACKGROUND: There have been recent reports of increased QT interval after head trauma in concussed athletes and adult patients. Ondansetron, which is widely used in treatment of nausea and vomiting symptoms in head injuries, was issued a safety warning from the U.S. Food and Drug Administration regarding QT prolongation and risk of fatal dysrhythmias. OBJECTIVE: The purpose of this study was to evaluate the safety of ondansetron regarding QT prolongation for patients experiencing nausea or vomiting after head trauma. METHODS: Patients aged 1-20 years presenting to a pediatric emergency department with head trauma and who required a dose of ondansetron for nausea or vomiting were enrolled in the study. Patients received a baseline 12-lead electrocardiogram (ECG) prior to administration of either oral or IV ondansetron. A second post-ondansetron 12-lead ECG was performed after administration of ondansetron. All ECGs were reviewed and the QTc calculated manually by a board-certified pediatric cardiologist. RESULTS: Forty-two patients met enrollment criteria. Five patients received IV ondansetron and 37 received oral ondansetron. Mean QTc pre ondansetron was 387.5 ms and mean QTc post ondansetron was 400.9 ms (p = 0.120). We found no statistically significant difference in other ECG parameters pre and post ondansetron. CONCLUSIONS: Ondansetron is safe in regard to QTc prolongation in patients with head trauma. Based on this research, ondansetron should continue to be used for the treatment of nausea and vomiting in emergency department patients who present with head injury.

YouTube-based course orientation videos delivered prior to matriculation fail to alleviate medical student anxiety about anatomy.

Gross anatomy is a source of anxiety for matriculating medical students due to the large volume of information presented in a truncated timeline, and because it may be their first exposure to human cadavers. This study aimed to assess if video-based resources would affect matriculating medical students' anatomy state anxiety levels. Videos were designed to be short, YouTube-based units that served to provide orientation information about the anatomy course, dissection facilities, and available study resources to dispel anxiety around beginning their anatomy studies. To evaluate the impact of the videos, students in two consecutive matriculating years (2018 and 2019) completed the validated State-Trait Anxiety Inventory and a demographic questionnaire. The 2019 cohort (n = 118) served as the experimental group with access to the videos; while the 2018 cohort (n = 120) without video access served as a historical control. Analyses revealed that the groups were equivalent in terms of trait anxiety (P = 0.854) and anatomy state anxiety even when student video exposure was controlled (P = 0.495). Anatomy state anxiety was only significantly lower in students with prior formal anatomy exposure (P = 0.006). Further inquiry into students' prior anatomy experience identified that individuals with post-secondary dissection experience were significantly less anxious than those without formal anatomical experience (P = 0.023). These results may serve as a cautionary tale to educators; while preference for video-based instructional materials is prevalent in the literature, videos delivered on public social media platforms fail to prepare students for the psychological impact of studying human anatomy.

Role of adipocyte Na,K-ATPase oxidant amplification loop in cognitive decline and neurodegeneration.

Recent studies suggest that a western diet may contribute to clinical neurodegeneration and dementia. Adipocyte-specific expression of the Na,K-ATPase signaling antagonist, NaKtide, ameliorates the pathophysiological consequences of murine experimental obesity and renal failure. In this study, we found that a western diet produced systemic oxidant stress along with evidence of activation of Na,K-ATPase signaling within both murine brain and peripheral tissues. We also noted this diet caused increases in circulating inflammatory cytokines as well as behavioral, and brain biochemical changes consistent with neurodegeneration. Adipocyte specific NaKtide affected by a doxycycline on/off expression system ameliorated all of these diet effects. These data suggest that a western diet produces cognitive decline and neurodegeneration through augmented Na,K-ATPase signaling and that antagonism of this pathway in adipocytes ameliorates the pathophysiology. If this observation is confirmed in humans, the adipocyte Na,K-ATPase may serve as a clinical target in the therapy of neurodegenerative disorders.

Hyaluronan and the Fascial Frontier.

The buzz about hyaluronan (HA) is real. Whether found in face cream to increase water volume loss and viscoelasticity or injected into the knee to restore the properties of synovial fluid, the impact of HA can be recognized in many disciplines from dermatology to orthopedics. HA is the most abundant polysaccharide of the extracellular matrix of connective tissues. HA can impact cell behavior in specific ways by binding cellular HA receptors, which can influence signals that facilitate cell survival, proliferation, adhesion, as well as migration. Characteristics of HA, such as its abundance in a variety of tissues and its responsiveness to chemical, mechanical and hormonal modifications, has made HA an attractive molecule for a wide range of applications. Despite being discovered over 80 years ago, its properties within the world of fascia have only recently received attention. Our fascial system penetrates and envelopes all organs, muscles, bones and nerve fibers, providing the body with a functional structure and an environment that enables all bodily systems to operate in an integrated manner. Recognized interactions between cells and their HA-rich extracellular microenvironment support the importance of studying the relationship between HA and the body's fascial system. From fasciacytes to chronic pain, this review aims to highlight the connections between HA and fascial health.

Adapting Strategically to Changing Times in Health Professions Education: A Generational Workshop for Educators.

Introduction: Health professions classrooms are filled with a new generation of students: iGen/generation Z. Much is known about millennials' educational needs, but they no longer comprise the majority of student populations. Research indicates that curricular strategies once useful for millennials may be ineffective for iGen. Due to multiple and surprising generational differences including ubiquitous technology, verbal/social/reading skills, and attention spans, educators might struggle to reach iGen members and are encouraged to re-examine instructional methods with iGen in mind. Methods: We designed this 90-minute workshop to give educators an informed understanding of iGen and discuss curricular adaptations intended to maintain educational quality through a literature-based presentation, self-assessment activities, and case discussions. We delivered the session to multiple diverse groups of health professions educators and staff. The attendees evaluated the workshop's quality and its longitudinal impact using 5-point Likert-style agreement surveys. Results: Respondents deemed the topic crucial to professional development and rated the content highly relevant (100% agreement/strong agreement). Longitudinal respondents could recognize iGen and personal characteristics (79% agreement or strong agreement) and the majority (58%) agreed/strongly agreed they were able to implement new instructional strategies. Discussion: Although educators are aware of typical generational differences, many are surprised to learn the unique attributes of their iGen student population. Workshop participation allowed educators to better understand both iGen students as well as how their own generational characteristics might relate to iGen members. Gaining this perspective allows educators to more adeptly create and deliver content to current health professions students.

Twelve tips for interfacing with the new generation of medical students: iGen.

iGen, or Generation Z, is the newest generation of health professions students to enter the classroom. This generation represents the first cohort of students in which technology has been present in all aspects of their lives. Since birth, they have been influenced by the boom of social media and wide-spread internet availability, leading to decreased face-to-face interactions and a desire for immediate access to information. Health professions educators should recognize the unique attributes of iGen students in order to foster student success and create a more positive learning environment. The following twelve tips examine the research-based distinctive characteristics of iGen students and highlight important concepts to consider when modifying current pedagogy to better support their needs. Incorporating these tips as an educator can promote lifelong learning and skill development for iGen students and empower this generation to thrive.

DLK1 Expressed in Mouse Orexin Neurons Modulates Anxio-Depressive Behavior but Not Energy Balance.

Lateral hypothalamic area (LHA) neurons expressing the neuropeptide orexin (OX) are implicated in obesity and anxio-depression. However, these neurons release OX as well as a host of other proteins that might contribute to normal physiology and disease states. We hypothesized that delta-like homolog 1 (DLK1), a protein reported to be co-expressed by all OX neurons, contributes to the regulation of energy balance and/or anxio-depression. Consistent with previous reports, we found that all rat OX neurons co-express DLK1. Yet, in mice and humans only a subset of OX neurons co-expressed DLK1. Since human OX-DLK1 distribution is more similar to mice than rats, mice are a comparable model to assess the human physiologic role of DLK1. We therefore used a viral lesion strategy to selectively delete DLK1 within the LHA of adult mice (DLK1Null) to reveal its role in body weight and behavior. Adult-onset DLK1 deletion had no impact on body weight or ingestive behavior. However, DLK1Null mice engaged in more locomotor activity than control mice and had decreased anxiety and depression measured via the elevated plus maze and forced swim tests. These data suggest that DLK1 expression via DLK1-expressing OX neurons primarily contributes to anxio-depression behaviors without impacting body weight.

Author Correction: The Adipocyte Na/K-ATPase Oxidant Amplification Loop is the Central Regulator of Western Diet-Induced Obesity and Associated Comorbidities.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Central Role for Adipocyte Na,K-ATPase Oxidant Amplification Loop in the Pathogenesis of Experimental Uremic Cardiomyopathy.

BACKGROUND: Oxidative stress in adipocyte plays a central role in the pathogenesis of obesity as well as in the associated cardiovascular complications. The putative uremic toxin indoxyl sulfate induces oxidative stress and dramatically alters adipocyte phenotype in vitro. Mice that have undergone partial nephrectomy serve as an experimental model of uremic cardiomyopathy. This study examined the effects on adipocytes of administering a peptide that reduces oxidative stress to the mouse model. METHODS: A lentivirus vector introduced the peptide NaKtide with an adiponectin promoter into the mouse model of experimental uremic cardiomyopathy, intraperitoneally. Then adipocyte-specific expression of the peptide was assessed for mice fed a standard diet compared with mice fed a western diet enriched in fat and fructose. RESULTS: Partial nephrectomy induced cardiomyopathy and anemia in the mice, introducing oxidant stress and an altered molecular phenotype of adipocytes that increased production of systemic inflammatory cytokines instead of accumulating lipids, within 4 weeks. Consumption of a western diet significantly worsened the adipocyte oxidant stress, but expression of NaKtide in adipocytes completely prevented the worsening. The peptide-carrying lentivirus achieved comparable expression in skeletal muscle, but did not ameliorate the disease phenotype. CONCLUSIONS: Adipocyte-specific expression of NaKtide, introduced with a lentiviral vector, significantly ameliorated adipocyte dysfunction and uremic cardiomyopathy in partially nephrectomized mice. These data suggest that the redox state of adipocytes controls the development of uremic cardiomyopathy in mice subjected to partial nephrectomy. If confirmed in humans, the oxidative state of adipocytes may be a therapeutic target in chronic renal failure.

The Na/K-ATPase α1 and c-Src form signaling complex under native condition: A crosslinking approach.

The protein-protein interactions amongst the Na/K-ATPase α1 subunit, c-Src, and caveolin-1 (cav-1) are essential for the Na/K-ATPase signaling functions. However, there are arguments concerning the interaction model. The present study aims to clarify the interactions amongst the endogenous native proteins in live cells under native resting condition. Under native condition, Blue Native-PAGE and Blue Native-PAGE/SDS-PAGE 2D analyses demonstrated co-existence of the α1 subunit and c-Src in same protein complex, as well as a direct interaction between the α1 subunit and c-Src. By comparison of cleavable and non-cleavable cysteine-cysteine crosslinked samples, capillary immunoblotting analysis demonstrated that depletion of Src kinase family members (c-Src, Yes, and Fyn) or cav-1 clearly reduced the interactions of the α1 subunit with proteins, but depletion of cav-1 did not affect the interaction of c-Src with the α1 subunit. The data indicated that there are direct interactions between the α1 subunit and c-Src as well as between the α1 subunit and cav-1, but argued about the interaction between c-Src and cav-1 under the condition. Furthermore, the data also indicated the existence of different protein complexes containing the α1 subunit and c-Src, which might have different signaling functions.

Mechanistic Insight of Na/K-ATPase Signaling and HO-1 into Models of Obesity and Nonalcoholic Steatohepatitis.

Obesity is a multifaceted pathophysiological condition that has been associated with lipid accumulation, adipocyte dysfunction, impaired mitochondrial biogenesis and an altered metabolic profile. Redox imbalance and excessive release of inflammatory mediators have been intricately linked in obesity-associated phenotypes. Hence, understanding the mechanisms of redox signaling pathways and molecular targets exacerbating oxidative stress is crucial in improving health outcomes. The activation of Na/K-ATPase/Src signaling, and its downstream pathways, by reactive oxygen species (ROS) has been recently implicated in obesity and subsequent nonalcoholic steatohepatitis (NASH), which causes further production of ROS creating an oxidant amplification loop. Apart from that, numerous studies have also characterized antioxidant properties of heme oxygenase 1 (HO-1), which is suppressed in an obese state. The induction of HO-1 restores cellular redox processes, which contributes to inhibition of the toxic milieu. The novelty of these independent mechanisms presents a unique opportunity to unravel their potential as molecular targets for redox regulation in obesity and NASH. The attenuation of oxidative stress, by understanding the underlying molecular mechanisms and associated mediators, with a targeted treatment modality may provide for improved therapeutic options to combat clinical disorders.

Metabolic Syndrome and Salt-Sensitive Hypertension in Polygenic Obese TALLYHO/JngJ Mice: Role of Na/K-ATPase Signaling.

We have demonstrated that Na/K-ATPase acts as a receptor for reactive oxygen species (ROS), regulating renal Na+ handling and blood pressure. TALLYHO/JngJ (TH) mice are believed to mimic the state of obesity in humans with a polygenic background of type 2 diabetes. This present work is to investigate the role of Na/K-ATPase signaling in TH mice, focusing on susceptibility to hypertension due to chronic excess salt ingestion. Age-matched male TH and the control C57BL/6J (B6) mice were fed either normal diet or high salt diet (HS: 2, 4, and 8% NaCl) to construct the renal function curve. Na/K-ATPase signaling including c-Src and ERK1/2 phosphorylation, as well as protein carbonylation (a commonly used marker for enhanced ROS production), were assessed in the kidney cortex tissues by Western blot. Urinary and plasma Na+ levels were measured by flame photometry. When compared to B6 mice, TH mice developed salt-sensitive hypertension and responded to a high salt diet with a significant rise in systolic blood pressure indicative of a blunted pressure-natriuresis relationship. These findings were evidenced by a decrease in total and fractional Na+ excretion and a right-shifted renal function curve with a reduced slope. This salt-sensitive hypertension correlated with changes in the Na/K-ATPase signaling. Specifically, Na/K-ATPase signaling was not able to be stimulated by HS due to the activated baseline protein carbonylation, phosphorylation of c-Src and ERK1/2. These findings support the emerging view that Na/K-ATPase signaling contributes to metabolic disease and suggest that malfunction of the Na/K-ATPase signaling may promote the development of salt-sensitive hypertension in obesity. The increased basal level of renal Na/K-ATPase-dependent redox signaling may be responsible for the development of salt-sensitive hypertension in polygenic obese TH mice.

The Adipocyte Na/K-ATPase Oxidant Amplification Loop is the Central Regulator of Western Diet-Induced Obesity and Associated Comorbidities.

Obesity has become a worldwide epidemic. We have previously reported that systemic administration of pNaKtide which targets the Na/K-ATPase oxidant amplification loop (NKAL) was able to decrease systemic oxidative stress and adiposity in mice fed a high fat and fructose supplemented western diet (WD). As adipocytes are believed to play a central role in the development of obesity and its related comorbidities, we examined whether lentiviral-mediated adipocyte-specific expression of NaKtide, a peptide derived from the N domain of the alpha1 Na/K-ATPase subunit, could ameliorate the effects of the WD. C57BL6 mice were fed a WD, which activated Na/K-ATPase signaling in the adipocytes and induced an obese phenotype and caused an increase in plasma levels of leptin, IL-6 and TNFα. WD also decreased locomotor activity, expression of the D2 receptor and tyrosine hydroxylase in brain tissue, while markers of neurodegeneration and neuronal apoptosis were increased following the WD. Selective adipocyte expression of NaKtide in these mice fed a WD attenuated all of these changes including the brain biochemical alterations and behavioral adaptations. These data suggest that adipocyte derived cytokines play an essential role in the development of obesity induced by a WD and that targeting the adipocyte NKAL loop may serve as an effective therapeutic strategy.

Educational avenues for promoting dialog on fascia.

If your healthcare professional students have not heard about the importance of fascia they definitely should, and if your residents have not heard about the manifestations of fascia health they definitely will from their patients. While fascia may not be the sexiest of organ systems, it is one of the most influential. Fascia is gaining interest from researchers, physicians, and many subdivisions of manual medicine including massage therapists. The fascial system is now being recognized with roles in pathology, fluid movement, and proprioception. It is also important in skeletal muscle movement, perception of pain, protein regulation and expression, cell signaling, neoplastic growth, and hormone distribution in our body. It can be the reason why we feel chronic pain or why we feel tightness after physical activity. The primary responsibility of fascia is to connect systems so that the body works as a whole, which is what permits this topic to be easily embedded anywhere in our health curricula. Whether you teach students in schools of medical, veterinary, dental, physical therapy, physician assistant studies, or occupational therapy, fascia matters. Whether you teach in an integrated curriculum or a curriculum that is designed for problem-based learning or a classical discipline-based curriculum, connective tissue has a place in academia. So, in our cramped curriculum how do we make sure that our current undergraduate and graduate students understand the complexity of fascia without adding additional time to coursework? To answer this question, this article demonstrates how fascia can fit anywhere in the curriculum because it is found everywhere. Clin. Anat. 32:871-876, 2019. © 2019 Wiley Periodicals, Inc.

Uremic Toxins Activates Na/K-ATPase Oxidant Amplification Loop Causing Phenotypic Changes in Adipocytes in In Vitro Models.

BACKGROUND: Oxidant stress plays a key role in the development of chronic kidney disease (CKD). Experimental CKD leads to accumulation of uremic toxins (UT) in the circulation resulting in increased ROS production, which in turn, is known to activate the Na/K-ATPase/ROS amplification loop. Studies in a murine model of obesity have shown that increased oxidative stress in plasma is due to increased ROS and cytokine production from dysfunctional adipocytes. Therefore, we hypothesized that adipocytes exposed to UTs will activate the Na/K-ATPase oxidant amplification loop causing redox imbalance and phenotypic alterations in adipocytes. We also aimed to demonstrate that the Na/K-ATPase signaling antagonist, pNaKtide, attenuates these pathophysiological consequences. METHODS: In the first set of experiments, 3T3-L1 murine pre-adipocytes were treated with varying concentrations of UTs, indoxyl sulfate (IS) (50, 100 and 250 µM) and p-cresol (50, 100 and 200 µM), with or without pNaKtide (0.7 µM) for five days in adipogenic media, followed by Oil Red O staining to study adipogenesis. RT-PCR analysis was performed to study expression of adipogenic, apoptotic and inflammatory markers, while DHE staining evaluated the superoxide levels in UT treated cells. In a second set of experiments, visceral fat was obtained from the West Virginian population. MSCs were isolated and cultured in adipogenic media for 14 days, which was treated with indoxyl sulfate (0, 25, 50 and 100 µM) with or without pNaKtide (1 µM). MSC-derived adipocytes were evaluated for morphological and molecular analysis of the above markers. RESULTS: Our results demonstrated that 3T3-L1 cells and MSCs-derived adipocytes, treated with UTs, exhibited a significant decrease in adipogenesis and apoptosis through activation of the Na/K-ATPase/ROS amplification loop. The treatment with pNaKtide in 3T3-L1 cells and MSC-derived adipocytes negated the effects of UTs and restored cellular redox in adipocytes. We noted a varying effect of pNaKtide, in adipocytes treated with UTs, on inflammatory markers, adipogenic marker and superoxide levels in 3T3-L1 cells and MSC-derived adipocytes. CONCLUSIONS: This study demonstrates for the first time that the Na/K-ATPase/ROS amplification loop activated by elevated levels of UTs has varying effect on phenotypic alterations in adipocytes in various in vitro models. Thus, we propose that, if proven in humans, inhibition of Na/K-ATPase amplification of oxidant stress in CKD patients may ultimately be a novel way to combat adipocyte dysfunction and metabolic imbalance in these patients.

The Na/K-ATPase Signaling: From Specific Ligands to General Reactive Oxygen Species.

The signaling function of the Na/K-ATPase has been established for 20 years and is widely accepted in the field, with many excellent reports and reviews not cited here. Even though there is debate about the underlying mechanism, the signaling function is unquestioned. This short review looks back at the evolution of Na/K-ATPase signaling, from stimulation by cardiotonic steroids (also known as digitalis-like substances) as specific ligands to stimulation by reactive oxygen species (ROS) in general. The interplay of cardiotonic steroids and ROS in Na/K-ATPase signaling forms a positive-feedback oxidant amplification loop that has been implicated in some pathophysiological conditions.

The Na/K-ATPase Oxidant Amplification Loop Regulates Aging.

As aging involves oxidant injury, we examined the role of the recently described Na/K-ATPase oxidant amplification loop (NKAL). First, C57Bl6 old mice were given a western diet to stimulate oxidant injury or pNaKtide to antagonize the NKAL. The western diet accelerated functional and morphological evidence for aging whereas pNaKtide attenuated these changes. Next, human dermal fibroblasts (HDFs) were exposed to different types of oxidant stress in vitro each of which increased expression of senescence markers, cell-injury, and apoptosis as well as stimulated the NKAL. Further stimulation of the NKAL with ouabain augmented cellular senescence whereas treatment with pNaKtide attenuated it. Although N-Acetyl Cysteine and Vitamin E also ameliorated overall oxidant stress to a similar degree as pNaKtide, the pNaKtide produced protection against senescence that was substantially greater than that seen with either antioxidant. In particular, pNaKtide appeared to specifically ameliorate nuclear oxidant stress to a greater degree. These data demonstrate that the NKAL is intimately involved in the aging process and may serve as a target for anti-aging interventions.