Gestational iron deficiency affects the ratio between interneuron subtypes in the postnatal cerebral cortex in mice.

Gestational iron deficiency (gID) is highly prevalent and associated with an increased risk of intellectual and developmental disabilities in affected individuals that are often defined by a disrupted balance of excitation and inhibition (E/I) in the brain. Using a nutritional mouse model of gID, we previously demonstrated a shift in the E/I balance towards increased inhibition in the brains of gID offspring that was refractory to postnatal iron supplementation. We thus tested whether gID affects embryonic progenitor cells that are fated towards inhibitory interneurons. We quantified relevant cell populations during embryonic inhibitory neuron specification and found an increase in the proliferation of Nkx2.1+ interneuron progenitors in the embryonic medial ganglionic eminence at E14 that was associated with increased Shh signaling in gID animals at E12. When we quantified the number of mature inhibitory interneurons that are known to originate from the MGE, we found a persistent disruption of differentiated interneuron subtypes in early adulthood. Our data identify a cellular target that links gID with a disruption of cortical interneurons which play a major role in the establishment of the E/I balance.

VP1 is the primary determinant of neuropathogenesis in a mouse model of enterovirus D68 acute flaccid myelitis.

Enterovirus D68 (EV-D68) is an emerging pathogen that can cause severe respiratory and neurologic disease [acute flaccid myelitis (AFM)]. Intramuscular (IM) injection of neonatal Swiss Webster (SW) mice with US/IL/14-18952 (IL52), a clinical isolate from the 2014 EV-D68 epidemic, results in many of the pathogenic features of human AFM, including viral infection of the spinal cord, death of motor neurons, and resultant progressive paralysis. In distinction, CA/14-4231 (CA4231), another clinical isolate from the 2014 EV-D68 outbreak, does not cause paralysis in mice, does not grow in the spinal cord, and does not cause motor neuron loss following IM injection. A panel of chimeric viruses containing sequences from IL52 and CA4231 was used to demonstrate that VP1 is the main determinant of EV-D68 neurovirulence following IM injection of neonatal SW mice. VP1 contains four amino acid differences between IL52 and CA4231. Mutations resulting in substituting these four amino acids (CA4231 residues into the IL52 polyprotein) completely abolished neurovirulence. Conversely, mutations resulting in substituting VP1 IL52 amino acid residues into the CA4231 polyprotein created a virus that induced paralysis to the same degree as IL52. Neurovirulence following infection of neonatal SW mice with parental and chimeric viruses was associated with viral growth in the spinal cord. IMPORTANCE: Emerging viruses allow us to investigate mutations leading to increased disease severity. Enterovirus D68 (EV-D68), once the cause of rare cases of respiratory illness, recently acquired the ability to cause severe respiratory and neurologic disease. Chimeric viruses were used to demonstrate that viral structural protein VP1 determines growth in the spinal cord, motor neuron loss, and paralysis following intramuscular (IM) injection of neonatal Swiss Webster (SW) mice with EV-D68. These results have relevance for predicting the clinical outcome of future EV-D68 epidemics as well as targeting retrograde transport as a potential strategy for treating virus-induced neurologic disease.

Telaprevir Treatment Reduces Paralysis in a Mouse Model of Enterovirus D68 Acute Flaccid Myelitis.

In 2014, 2016, and 2018, the United States experienced unprecedented spikes in pediatric cases of acute flaccid myelitis (AFM), which is a poliomyelitis-like paralytic illness. Accumulating clinical, immunological, and epidemiological evidence has identified enterovirus D68 (EV-D68) as a major causative agent of these biennial AFM outbreaks. There are currently no available FDA-approved antivirals that are effective against EV-D68, and the treatment for EV-D68-associated AFM is primarily supportive. Telaprevir is an food and drug administration (FDA)-approved protease inhibitor that irreversibly binds the EV-D68 2A protease and inhibits EV-D68 replication in vitro. Here, we utilize a murine model of EV-D68 associated AFM to show that early telaprevir treatment improves paralysis outcomes in Swiss Webster (SW) mice. Telaprevir reduces both viral titer and apoptotic activity in both muscles and spinal cords at early disease time points, which results in improved AFM outcomes in infected mice. Following intramuscular inoculation in mice, EV-D68 infection results in a stereotypic pattern of weakness that is reflected by the loss of the innervating motor neuron population, in sequential order, of the ipsilateral (injected) hindlimb, the contralateral hindlimb, and then the forelimbs. Telaprevir treatment preserved motor neuron populations and reduced weakness in limbs beyond the injected hindlimb. The effects of telaprevir were not seen when the treatment was delayed, and toxicity limited doses beyond 35 mg/kg. These studies are a proof of principle, provide the first evidence of benefit of an FDA-approved antiviral drug with which to treat AFM, and emphasize both the need to develop better tolerated therapies that remain efficacious when administered after viral infections and the development of clinical symptoms. IMPORTANCE Recent outbreaks of EV-D68 in 2014, 2016, and 2018 have resulted in over 600 cases of a paralytic illness that is known as AFM. AFM is a predominantly pediatric disease with no FDA-approved treatment, and many patients show minimal recovery from limb weakness. Telaprevir is an FDA-approved antiviral that has been shown to inhibit EV-D68 in vitro. Here, we demonstrate that a telaprevir treatment that is given concurrently with an EV-D68 infection improves AFM outcomes in mice by reducing apoptosis and viral titers at early time points. Telaprevir also protected motor neurons and improved paralysis outcomes in limbs beyond the site of viral inoculation. This study improves understanding of EV-D68 pathogenesis in the mouse model of AFM. This study serves as a proof of principle for the first FDA-approved drug that has been shown to improve AFM outcomes and have in vivo efficacy against EV-D68 as well as underlines the importance of the continued development of EV-D68 antivirals.

Neutralizing Antibody Given after Paralysis Onset Reduces the Severity of Paralysis Compared to Nonspecific Antibody-Treated Controls in a Mouse Model of EV-D68-Associated Acute Flaccid Myelitis.

Enterovirus D68 (EV-D68) can cause mild to severe respiratory illness and is associated with a poliomyelitis-like paralytic syndrome called acute flaccid myelitis (AFM). Most cases of EV-D68-associated AFM occur in young children who are brought to the clinic after the onset of neurologic symptoms. There are currently no known antiviral therapies for AFM, and it is unknown whether antiviral treatments will be effective if initiated after the onset of neurologic symptoms (when patients are likely to present for medical care). We developed a "clinical treatment model" for AFM, in which individual EV-D68-infected mice are tracked and treated with an EV-D68-specific human-mouse chimeric monoclonal antibody after the onset of moderate paralysis. Mice treated with antibody had significantly better paralysis outcomes compared to nonspecific antibody-treated controls. Treatment did not reverse paralysis that was present at the time of treatment initiation but did slow the further loss of function, including progression of weakness to other limbs, as well as reducing viral titer in the muscle and spinal cords of treated animals. We observed the greatest therapeutic effect in EV-D68 isolates which were neutralized by low concentrations of antibody, and diminishing therapeutic effect in EV-D68 isolates which required higher doses of antibody for neutralization. This work supports the use of virus-specific immunotherapy for the treatment of AFM. It also suggests that patients who present with AFM should be treated as soon as possible if recent infection with EV-D68 is suspected.

The Patient with Hip Fracture.

Hip fractures are a frequent cause of hospitalization in the elderly population and can lead to significant morbidity and mortality. As the population continues to age, the incidence of hip fractures is expected to increase. The internist/hospitalist plays a critical role in the care of this population as many patients have multiple medical comorbidities. Management of the fragility hip fracture patient requires knowledge of several perioperative topics including preoperative risk assessment, risk reduction strategies, the optimal timing of surgical repair, venous thromboembolism prevention, and postoperative care considerations such as early mobilization with physical therapy, and osteoporosis treatment.

Efficacy of an isoxazole-3-carboxamide analog of pleconaril in mouse models of Enterovirus-D68 and Coxsackie B5.

Enteroviruses (EV) cause a number of life-threatening infectious diseases. EV-D68 is known to cause respiratory illness in children that can lead to acute flaccid myelitis. Coxsackievirus B5 (CVB5) is commonly associated with hand-foot-mouth disease. There is no antiviral treatment available for either. We have developed an isoxazole-3-carboxamide analog of pleconaril (11526092) which displayed potent inhibition of EV-D68 (IC50 58 nM) as well as other enteroviruses including the pleconaril-resistant Coxsackievirus B3-Woodruff (IC50 6-20 nM) and CVB5 (EC50 1 nM). Cryo-electron microscopy structures of EV-D68 in complex with 11526092 and pleconaril demonstrate destabilization of the EV-D68 MO strain VP1 loop, and a strain-dependent effect. A mouse respiratory model of EV-D68 infection, showed 3-log decreased viremia, favorable cytokine response, as well as statistically significant 1-log reduction in lung titer reduction at day 5 after treatment with 11526092. An acute flaccid myelitis neurological infection model did not show efficacy. 11526092 was tested in a mouse model of CVB5 infection and showed a 4-log TCID50 reduction in the pancreas. In summary, 11526092 represents a potent in vitro inhibitor of EV with in vivo efficacy in EV-D68 and CVB5 animal models suggesting it is worthy of further evaluation as a potential broad-spectrum antiviral therapeutic against EV.

Density Analysis of Enterovirus D68 Shows Viral Particles Can Associate with Exosomes.

Enterovirus D68 (EV-D68) is an emerging pathogen which causes respiratory disease and is associated with an acute flaccid myelitis that predominately affects children. EV-D68 can infect motor neurons, causing cell death and a loss of motor control leading to flaccid paralysis. However, it remains unknown how viral particles gain entry into the central nervous system (CNS). Here, we show that three distinct densities of EV-D68 particle can be isolated from infected muscle and neural cell lines (RD and SH-SY5Y) using high-speed density centrifugation to separate cell supernatant. The lowest-density peak is composed of viral particles, which have adhered to the exterior surface of a small extracellular vesicle called an exosome. Analysis of prototypic (historic) and contemporary EV-D68 strains suggests that binding to exosomes is a ubiquitous characteristic of EV-D68. We further show that interaction with exosomes increases viral infectivity in a neural cell line. Analysis of the two higher-density peaks, which are not associated with exosomes, revealed that a significant amount of viral titer in the modern (2014) EV-D68 strains is found at 1.20 g/cm3, whereas this density has a very low viral titer in the prototypic Fermon strain. IMPORTANCE Despite the strong causal link between enterovirus D68 (EV-D68) and acute flaccid myelitis (AFM), it remains unclear how EV-D68 gains entry into the central nervous system and what receptors enable it to infect motor neurons. We show that EV-D68 particles can adhere to exosomes, placing EV-D68 among a handful of other picornaviruses which are known to interact with extracellular vesicles. Uptake and infection of permissive cells by virally contaminated exosomes would have major implications in the search for the EV-D68 receptor, as well as providing a possible route for viral entry into motor neurons. This work identifies a novel cellular entry route for EV-D68 and may facilitate the identification of genetic risk factors for development of AFM.

Foams with Enhanced Rheology for Stopping Bleeding.

Bleeding from injuries to the torso region is a leading cause of fatalities in the military and in young adults. Such bleeding cannot be stopped by applying direct pressure (compression) of a bandage. An alternative is to introduce a foam at the injury site, with the expansion of the foam counteracting the bleeding. Foams with an active hemostatic agent have been tested for this purpose, but the barrier created by these foams is generally not strong enough to resist blood flow. In this paper, we introduce a new class of foams with enhanced rheological properties that enable them to form a more effective barrier to blood loss. These aqueous foams are delivered out of a double-barrelled syringe by combining precursors that produce bubbles of gas (CO2) in situ. In addition, one barrel contains a cationic polymer (hydrophobically modified chitosan, hmC) and the other an anionic polymer (hydrophobically modified alginate, hmA). Both these polymers function as hemostatic agents due to their ability to connect blood cells into networks. The amphiphilic nature of these polymers also enables them to stabilize gas bubbles without the need for additional surfactants. hmC-hmA foams have a mousse-like texture and exhibit a high modulus and yield stress. Their properties are attributed to the binding of hmC and hmA chains (via electrostatic and hydrophobic interactions) to form a coacervate around the gas bubbles. Rheological studies are used to contrast the improved rheology of hmC-hmA foams (where a coacervate arises) with those formed by hmC alone (where there is no such coacervate). Studies with animal wound models also confirm that the hmC-hmA foams are more effective at curtailing bleeding than the hmC foams due to their greater mechanical integrity.

Extracellular vesicles released by human retinal pigment epithelium mediate increased polarised secretion of drusen proteins in response to AMD stressors.

Age-related macular degeneration (AMD) is a leading cause of blindness worldwide. Drusen are key contributors to the etiology of AMD and the ability to modulate drusen biogenesis could lead to therapeutic strategies to slow or halt AMD progression. The mechanisms underlying drusen biogenesis, however, remain mostly unknown. Here we demonstrate that under homeostatic conditions extracellular vesicles (EVs) secreted by retinal pigment epithelium (RPE) cells are enriched in proteins associated with mechanisms involved in AMD pathophysiology, including oxidative stress, immune response, inflammation, complement system and drusen composition. Furthermore, we provide first evidence that drusen-associated proteins are released as cargo of extracellular vesicles secreted by RPE cells in a polarised apical:basal mode. Notably, drusen-associated proteins exhibited distinctive directional secretion modes in homeostatic conditions and, differential modulation of this directional secretion in response to AMD stressors. These observations underpin the existence of a finely-tuned mechanism regulating directional apical:basal sorting and secretion of drusen-associated proteins via EVs, and its modulation in response to mechanisms involved in AMD pathophysiology. Collectively, our results strongly support an active role of RPE-derived EVs as a key source of drusen proteins and important contributors to drusen development and growth.

Determinants of Cost Variation in Total Hip and Knee Arthroplasty: Implications for Alternative Payment Models.

BACKGROUND: Alternative payment models have been proposed to deliver high-quality, cost-effective care. Under these models, payments may be shared between the hospital and the post-acute care services. Post-acute care services may account for one-third of the episode costs for total hip or knee arthroplasty (THA/TKA). Because hospitals or episode initiators bear notable financial risks in these payment models with minimal risk adjustment for complexity, it has been suggested these models may lead to prospective selection of healthier and younger patients. Studies evaluating the effect of patient demographics, medical complexity, and surgical characteristics on the cost of index hospitalization have been limited. We aimed to (1) quantify the impact of patient demographics, medical complexity, and surgical characteristics (type of anesthesia and operating time) on variation in direct cost of index hospitalization and (2) examine the association of these characteristics with discharge with home health services or to rehabilitation facility. METHODS: Retrospective study of 3,542 patients admitted to our hospital for elective THA/TKA between 2012 and 2017. Multivariable generalized estimating equations were used for analysis. RESULTS: Patient demographics and medical complexity accounted for 6.2% (THA) and 5.6% (TKA) of variation in direct cost of index hospitalization. Surgical characteristics accounted for 37.1% (THA) and 35.3% (TKA) of the cost variation. One thousand one hundred eighty-three (53.4%) patients were discharged with home health services, and 1,237 (29.4%) were discharged to rehabilitation facility. Patient demographics and higher medical complexity were markedly associated with discharge with home health services or to rehabilitation facility after THA/TKA. DISCUSSION: Patient demographics and medical complexity had minimal impact on variation in direct cost of index hospitalization for elective THA/TKA compared with surgical characteristics but were markedly associated with discharge with home health services or to rehabilitation facility. Having additional risk adjustment in these payment models could mitigate concerns about access to care for higher risk, higher cost patients.

Understanding Enterovirus D68-Induced Neurologic Disease: A Basic Science Review.

In 2014, the United States (US) experienced an unprecedented epidemic of enterovirus D68 (EV-D68)-induced respiratory disease that was temporally associated with the emergence of acute flaccid myelitis (AFM), a paralytic disease occurring predominantly in children, that has a striking resemblance to poliomyelitis. Although a definitive causal link between EV-D68 infection and AFM has not been unequivocally established, rapidly accumulating clinical, immunological, and epidemiological evidence points to EV-D68 as the major causative agent of recent seasonal childhood AFM outbreaks in the US. This review summarizes evidence, gained from in vivo and in vitro models of EV-D68-induced disease, which demonstrates that contemporary EV-D68 strains isolated during and since the 2014 outbreak differ from historical EV-D68 in several factors influencing neurovirulence, including their genomic sequence, their receptor utilization, their ability to infect neurons, and their neuropathogenicity in mice. These findings provide biological plausibility that EV-D68 is a causal agent of AFM and provide important experimental models for studies of pathogenesis and treatment that are likely to be difficult or impossible in humans.

Iron Deficiency Affects Seizure Susceptibility in a Time- and Sex-Specific Manner.

Iron deficiency (ID) affects more than three billion people worldwide making it the most common micronutrient deficiency. ID is most prevalent during gestation and early life, which is of particular concern since its impact on the developing central nervous system is associated with an increased risk of a wide range of different psychiatric disorders later in life. The cause for this association is not known, but many of these same disorders are also associated with an imbalance between excitation and inhibition (E/I) within the brain. Based on this shared impairment, we asked whether ID could contribute to such an imbalance. Disruptions in the E/I balance can be uncovered by the brain's response to seizure inducing insults. We therefore tested the seizure threshold under different nutritional models of ID. We found that mice which were postnatally exposed to ID (and were acutely ID) had a decreased seizure threshold and increased susceptibility to certain seizure types. In contrast, mice that were exposed to ID only during gestation had an increased seizure threshold and low seizure incidence. We suggest that exposure to ID during gestation might alter the cellular components that contribute to the establishment of a proper E/I balance later in life. In addition, our data highlight the importance of considering the window of vulnerability since gestational ID and postnatal ID have significantly different consequences on seizure probability.

Validation of Test Performance and Clinical Time Zero for an Electronic Health Record Embedded Severe Sepsis Alert.

BACHGROUND: Increasing use of EHRs has generated interest in the potential of computerized clinical decision support to improve treatment of sepsis. Electronic sepsis alerts have had mixed results due to poor test characteristics, the inability to detect sepsis in a timely fashion and the use of outside software limiting widespread adoption. We describe the development, evaluation and validation of an accurate and timely severe sepsis alert with the potential to impact sepsis management. OBJECTIVE: To develop, evaluate, and validate an accurate and timely severe sepsis alert embedded in a commercial EHR. METHODS: The sepsis alert was developed by identifying the most common severe sepsis criteria among a cohort of patients with ICD 9 codes indicating a diagnosis of sepsis. This alert requires criteria in three categories: indicators of a systemic inflammatory response, evidence of suspected infection from physician orders, and markers of organ dysfunction. Chart review was used to evaluate test performance and the ability to detect clinical time zero, the point in time when a patient develops severe sepsis. RESULTS: Two physicians reviewed 100 positive cases and 75 negative cases. Based on this review, sensitivity was 74.5%, specificity was 86.0%, the positive predictive value was 50.3%, and the negative predictive value was 94.7%. The most common source of end-organ dysfunction was MAP less than 70 mm/Hg (59%). The alert was triggered at clinical time zero in 41% of cases and within three hours in 53.6% of cases. 96% of alerts triggered before a manual nurse screen. CONCLUSION: We are the first to report the time between a sepsis alert and physician chart-review clinical time zero. Incorporating physician orders in the alert criteria improves specificity while maintaining sensitivity, which is important to reduce alert fatigue. By leveraging standard EHR functionality, this alert could be implemented by other healthcare systems.