Simian varicella virus infection and reactivation in rhesus macaques trigger cytokine and Aß40/42 alterations in serum and cerebrospinal fluid.

Simian varicella virus (SVV) produces peripheral inflammatory responses during varicella (primary infection) and zoster (reactivation) in rhesus macaques (RM). However, it is unclear if peripheral measures are accurate proxies for central nervous system (CNS) responses. Thus, we analyzed cytokine and Aß42/Aß40 changes in paired serum and cerebrospinal fluid (CSF) during the course of infection. During varicella and zoster, every RM had variable changes in serum and CSF cytokine and Aß42/Aß40 levels compared to pre-inoculation levels. Overall, peripheral infection appears to affect CNS cytokine and Aß42/Aß40 levels independent of serum responses, suggesting that peripheral disease may contribute to CNS disease.

Mechanisms underlying immunosuppression by regulatory cells.

Regulatory cells, such as regulatory T cells (Tregs), regulatory B cells (Bregs), and myeloid-derived suppressor cells (MDSCs), play a crucial role in preserving immune tolerance and controlling immune responses during infections to prevent excessive immune activation. However, pathogens have developed strategies to hijack these regulatory cells to decrease the overall effectiveness of the immune response and persist within the host. Consequently, therapeutic targeting of these immunosuppressive mechanisms during infection can reinvigorate the immune response and improve the infection outcome. The suppressive mechanisms of regulatory cells are not only numerous but also redundant, reflecting the complexity of the regulatory network in modulating the immune responses. The context of the immune response, such as the type of pathogen or tissue involved, further influences the regulatory mechanisms involved. Examples of these immunosuppressive mechanisms include the production of inhibitory cytokines such as interleukin 10 (IL-10) and transforming growth factor beta (TGF-ß) that inhibit the production of pro-inflammatory cytokines and dampen the activation and proliferation of effector T cells. In addition, regulatory cells utilize inhibitory receptors like cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1) to engage with their respective effector cells, thereby suppressing their function. An alternative approach involves the modulation of metabolic reprogramming in effector immune cells to limit their activation and proliferation. In this review, we provide an overview of the major mechanisms mediating the immunosuppressive effect of the different regulatory cell subsets in the context of infection.

Aerosolized delivery of ESKAPE pathogens for murine pneumonia models.

Murine pneumonia models for ESKAPE pathogens serve to evaluate novel antibacterials or to investigate immunological responses. The majority of published models uses intranasal or to a limited extent the intratracheal instillation to challenge animals. In this study, we propose the aerosol delivery of pathogens using a nebulizer. Aerosol delivery typically results in homogeneous distribution of the inoculum in the lungs because of lower particle size. This is of particular importance when compounds are assessed for their pharmacokinetic and pharmacodynamic (PK/PD) relationships as it allows to conduct several analysis with the same sample material. Moreover, aerosol delivery has the advantage that it mimics the 'natural route' of respiratory infection. In this short and concise study, we show that aerosol delivery of pathogens resulted in a sustained bacterial burden in the neutropenic lung infection model for five pathogens tested, whereas it gave a similar result in immunocompetent mice for three out of five pathogens. Moreover, a substantial bacterial burden in the lungs was already achieved 2 h post inhalation. Hence, this study constitutes a viable alternative for intranasal administration and a refinement of murine pneumonia models for PK/PD assessments of novel antibacterial compounds allowing to study multiple readouts with the same sample material.

Simian Varicella Virus Infection and Reactivation in Rhesus Macaques Trigger Cytokine and Aß40/42 Alterations in Serum and Cerebrospinal Fluid.

Simian varicella virus (SVV) produces peripheral inflammatory responses during varicella (primary infection) and zoster (reactivation) in rhesus macaques (RM). However, it is unclear if peripheral measures are accurate proxies for central nervous system (CNS) responses. Thus, we analyzed cytokine and Aß42/Aß40 changes in paired serum and cerebrospinal fluid (CSF) during the course of infection. During varicella and zoster, every RM had variable changes in serum and CSF cytokine and Aß42/Aß40 levels compared to pre-inoculation levels. Overall, peripheral infection appears to affect CNS cytokine and Aß42/Aß40 levels independent of serum responses, suggesting that peripheral disease may contribute to CNS disease.

Prevalence and Clinical Characteristics of Children With Nonsevere Tuberculosis in Spain.

BACKGROUND: To assess the prevalence and characteristics of nonsevere TB among children in Spain. It has been recently demonstrated that these children can be treated with a 4-month regimen instead of the classical 6-month treatment regimen, with the same effectivity and outcomes, decreasing toxicity and improving adherence. METHODS: We conducted a retrospective cohort study in a cohort of children ≤16 years of age with TB. Nonsevere TB cases included smear-negative children with respiratory TB confined to 1 lobe, with no significant airway obstruction, no complex pleural effusion, no cavities and no signs of miliary disease, or with peripheral lymph-node disease. The remaining children were considered to have severe TB. We estimated the prevalence of nonsevere TB and compared the clinical characteristics and outcomes between children with nonsevere and severe TB. RESULTS: A total of 780 patients were included [46.9% males, median age 5.5 years (IQR: 2.6-11.1)], 477 (61.1%) of whom had nonsevere TB. Nonsevere TB was less frequent in children <1 year (33% vs 67%; P < 0.001), and >14 years of age (35% vs 65%; P = 0.002), mostly diagnosed in contact tracing studies (60.4% vs 29.2%; P < 0.001) and more frequently asymptomatic (38.3% vs 17.7%; P < 0.001). TB confirmation in nonsevere disease was less frequent by culture (27.0% vs 57.1%; P < 0.001) and by molecular tests (18.2% vs 48.8%; P < 0.001). Sequelae were less frequent in children with nonsevere disease (1.7 vs 5.4%; P < 0.001). No child with nonsevere disease died. CONCLUSIONS: Two-thirds of children had nonsevere TB, mostly with benign clinical presentation and negative microbiologic results. In low-burden countries, most children with TB might benefit from short-course regimens.

Murine Gammaherpesvirus 68 Efficiently Infects Myeloid Cells Resulting In An Atypical, Restricted Form Of Infection.

The gammaherpesviruses (γHVs) establish a lifelong infection in their hosts, with the cellular outcome of infection intimately regulated by target cell type. Murine gammaherpesvirus 68 (MHV68), a small animal model of γHV infection, infects macrophages in vivo, resulting in a range of outcomes, from lytic replication to latent infection. Here, we have further investigated the nature of MHV68 macrophage infection using reductionist and primary in vivo infection studies. While MHV68 readily infected the J774 macrophage cell line, viral gene expression and replication were significantly impaired relative to a fully permissive fibroblast cell line. Lytic replication only occurred in a small subset of MHV68-infected J774 cells, despite the fact that these cells were fully competent to support lytic replication following pre-treatment with interleukin-4, a known potentiator of replication in macrophages. In parallel, we harvested virally-infected macrophages at 16 hours after MHV68 infection in vivo and analyzed gene expression by single cell RNA-sequencing. Among virally infected macrophages, only rare (0.25%) cells had lytic cycle gene expression, characterized by detection of multiple lytic cycle RNAs. In contrast, ~50% of virally-infected macrophages were characterized by expression of ORF75A, ORF75B and/or ORF75C, in the absence of other detectable viral RNAs. Selective transcription of the ORF75 locus also occurred in MHV68-infected J774 cells. In total, these studies indicate that MHV68 efficiently infects macrophages, with the majority of cells characterized by an atypical state of restricted viral transcription, and only rare cells undergoing lytic replication.

Myeloid-derived suppressor cells impair CD4+ T cell responses during chronic Staphylococcus aureus infection via lactate metabolism.

Staphylococcus aureus is an important cause of chronic infections resulting from the failure of the host to eliminate the pathogen. Effective S. aureus clearance requires CD4+ T cell-mediated immunity. We previously showed that myeloid-derived suppressor cells (MDSC) expand during staphylococcal infections and support infection chronicity by inhibiting CD4+ T cell responses. The aim of this study was to elucidate the mechanisms underlying the suppressive effect exerted by MDSC on CD4+ T cells during chronic S. aureus infection. It is well known that activated CD4+ T cells undergo metabolic reprogramming from oxidative metabolism to aerobic glycolysis to meet their increased bioenergetic requirements. In this process, pyruvate is largely transformed into lactate by lactate dehydrogenase with the concomitant regeneration of NAD+, which is necessary for continued glycolysis. The by-product lactate needs to be excreted to maintain the glycolytic flux. Using SCENITH (single-cell energetic metabolism by profiling translation inhibition), we demonstrated here that MDSC inhibit CD4+ T cell responses by interfering with their metabolic activity. MDSC are highly glycolytic and excrete large amount of lactate in the local environment that alters the transmembrane concentration gradient and prevent removal of lactate by activated CD4+ T. Accumulation of endogenous lactate impedes the regeneration of NAD+, inhibit NAD-dependent glycolytic enzymes and stop glycolysis. Together, the results of this study have uncovered a role for metabolism on MDSC suppression of CD4+ T cell responses. Thus, reestablishment of their metabolic activity may represent a mean to improve the functionality of CD4+ T cells during chronic S. aureus infection.

In silico predicted therapy against chronic Staphylococcus aureus infection leads to bacterial clearance in vivo.

Staphylococcus aureus can lead to chronic infections and abscesses in internal organs including kidneys, which are associated with the expansion of myeloid-derived suppressor cells (MDSCs) and their suppressive effect on T cells. Here, we developed a mathematical model of chronic S. aureus infection that incorporates the T-cell suppression by MDSCs and suggests therapeutic strategies for S. aureus clearance. A therapeutic protocol with heat-killed S. aureus (HKSA) was quantified in silico and tested in vivo. Contrary to the conventional administration of heat-killed bacteria as vaccination prior to infection, we administered HKSA as treatment in chronically infected hosts. Our treatment eliminated S. aureus in kidneys of all chronically S. aureus-infected mice, reduced MDSCs, and reversed T-cell dysfunction by inducing acute inflammation during ongoing, chronic infection. This study is a guideline for a treatment protocol against chronic S. aureus infection and renal abscesses by repurposing heat-killed treatments, directed by mathematical modeling.

Promoting Health Education through Mobile Apps: A Quantitative Analysis of American Hospitals.

Using mobile apps as a corporate communication tool helps hospitals to improve their health education initiatives. This paper aims to analyze how these organizations can use mobile apps to implement health education initiatives addressed to patients. To achieve this, we conducted a literature review (health education, mobile apps, role of doctors and patients), and we resorted to using 38 quantitative indicators to evaluate how the 100 best hospitals in the United States manage mobile apps for implementing health education initiatives addressed to patients. Our results prove that 95% of hospitals displayed general mobile apps for patients, but just some of these organizations proposed mobile apps for patients suffering from non-communicable diseases, including: heart diseases (9.47%), cancer (7.37%), chronic respiratory diseases (3.26%), and diabetes (3.16%). We concluded that hospitals should create a department specializing in designing mobile apps that are adapted to patients' medical and social needs, and that are also consistent with public health priorities.

Accuracy of Xpert Ultra for the diagnosis of paediatric tuberculosis in a low TB burden country: a prospective multicentre study.

INTRODUCTION: Childhood pulmonary tuberculosis (TB) remains a diagnostic challenge. This study aimed to evaluate the performance of Xpert Ultra for the diagnosis of pulmonary TB in children in a low TB prevalence setting. METHODS: Prospective, multicentre, diagnostic accuracy study. Children with clinical or radiological suspicion of pulmonary TB were recruited at 11 paediatric units in Spain. Up to three gastric or sputum specimens were taken on 3 consecutive days, and analysed by Xpert MTB/RIF, Xpert Ultra and culture in parallel. RESULTS: 86 children were included (median age 4.9 years, IQR 2.0-10.0; 51.2% male). The final diagnosis was pulmonary TB in 75 patients (87.2%); 33 (44.0%) were microbiologically confirmed. A total of 219 specimens, comprising gastric aspirates (n=194; 88.6%) and sputum specimens (n=25; 11.4%), were analysed. Using culture as reference standard and comparing individual specimens, the sensitivity was 37.8% (14/37) for Xpert MTB/RIF and 81.1% (30/37) for Xpert Ultra (p<0.001); specificity was 98.4% (179/182) and 93.4% (170/182), respectively (p=0.02). In the per-patient analysis, considering positive results on any specimen, the sensitivity was 42.9% (9/21) for Xpert MTB/RIF and 81.0% for Xpert Ultra (17/21, p=0.01); specificity was 96.9% (63/65) and 87.7% (57/65, p=0.07), respectively. CONCLUSIONS: In children with pulmonary TB in a low burden setting, Xpert Ultra has significantly higher sensitivity than the previous generation of Xpert assay and only marginally lower specificity. Therefore, in children undergoing evaluation for suspected pulmonary TB, Xpert Ultra should be used in preference to Xpert MTB/RIF whenever possible.

A Photoconvertible Reporter System for Bacterial Metabolic Activity Reveals That Staphylococcus aureus Enters a Dormant-Like State to Persist within Macrophages.

Staphylococcus aureus is a leading cause of difficult-to-treat infections. The capacity of S. aureus to survive and persist within phagocytic cells is an important factor contributing to therapy failures and infection recurrence. Therefore, interfering with S. aureus intracellular persistence is key to treatment success. In this study, we used a S. aureus strain carrying the reporter mKikumeGR that enables the monitoring of the metabolic status of intracellular bacteria to achieve a better understanding of the molecular mechanisms facilitating S. aureus survival and persistence within macrophages. We found that shortly after bacteria internalization, a large fraction of macrophages harbored mainly S. aureus with high metabolic activity. This population decreased gradually over time with the concomitant increase of a macrophage subpopulation harboring S. aureus with low metabolic activity, which prevailed at later times. A dual RNA-seq analysis performed in each macrophage subpopulation showed that the host transcriptional response was similar between both subpopulations. However, intracellular S. aureus exhibited disparate gene expression profiles depending on its metabolic state. Whereas S. aureus with high metabolic activity exhibited a greater expression of genes involved in protein synthesis and proliferation, bacteria with low metabolic activity displayed a higher expression of oxidative stress response-related genes, silenced genes involved in energy-consuming processes, and exhibited a dormant-like state. Consequently, we propose that reducing metabolic activity and entering into a dormant-like state constitute a survival strategy used by S. aureus to overcome the adverse environment encountered within macrophages and to persist in the intracellular niche. IMPORTANCE The capacity of Staphylococcus aureus to survive and persist within phagocytic cells has been associated with antibiotic treatment failure and recurrent infections. Here, we investigated the molecular mechanisms leading to S. aureus persistence within macrophages using a reporter system that enables to distinguish between intracellular bacteria with high and low metabolic activity in combinstion with a dual RNA-seq approach. We found that with the progression of infection, intracellular S. aureus transitions from a high metabolic state to a low metabolic dormant-like state by turning off major energy-consuming processes while remaining viable. This process seems to be driven by the level of stress encountered in the intracellular niche. Our study indicates that effective therapies by which to treat S. aureus infections should be able to target not only high metabolic bacteria but also intracellular dormant-like S. aureus.

Itaconate controls its own synthesis via feedback-inhibition of reverse TCA cycle activity at IDH2.

Macrophages undergo extensive metabolic reprogramming during classical pro-inflammatory polarization (M1-like). The accumulation of itaconate has been recognized as both a consequence and mediator of the inflammatory response. In this study we first examined the specific functions of itaconate inside fractionated mitochondria. We show that M1 macrophages produce itaconate de novo via aconitase decarboxylase 1 (ACOD1) inside mitochondria. The carbon for this reaction is not only supplied by oxidative TCA cycling, but also through the reductive carboxylation of α-ketoglutarate by isocitrate dehydrogenase (IDH). While macrophages are capable of sustaining a certain degree of itaconate production during hypoxia by augmenting the activity of IDH-dependent reductive carboxylation, we demonstrate that sufficient itaconate synthesis requires a balance of reductive and oxidative TCA cycle metabolism in mouse macrophages. In comparison, human macrophages increase itaconate accumulation under hypoxic conditions by augmenting reductive carboxylation activity. We further demonstrated that itaconate attenuates reductive carboxylation at IDH2, restricting its own production and the accumulation of the immunomodulatory metabolites citrate and 2-hydroxyglutarate. In line with this, reductive carboxylation is enhanced in ACOD1-depleted macrophages. Mechanistically, the inhibition of IDH2 by itaconate is linked to the alteration of the mitochondrial NADP+/NADPH ratio and competitive succinate dehydrogenase inhibition. Taken together, our findings extend the current model of TCA cycle reprogramming during pro-inflammatory macrophage activation and identified novel regulatory properties of itaconate.

Mesaconate is synthesized from itaconate and exerts immunomodulatory effects in macrophages.

Since its discovery in inflammatory macrophages, itaconate has attracted much attention due to its antimicrobial and immunomodulatory activity1-3. However, instead of investigating itaconate itself, most studies used derivatized forms of itaconate and thus the role of non-derivatized itaconate needs to be scrutinized. Mesaconate, a metabolite structurally very close to itaconate, has never been implicated in mammalian cells. Here we show that mesaconate is synthesized in inflammatory macrophages from itaconate. We find that both, non-derivatized itaconate and mesaconate dampen the glycolytic activity to a similar extent, whereas only itaconate is able to repress tricarboxylic acid cycle activity and cellular respiration. In contrast to itaconate, mesaconate does not inhibit succinate dehydrogenase. Despite their distinct impact on metabolism, both metabolites exert similar immunomodulatory effects in pro-inflammatory macrophages, specifically a reduction of interleukin (IL)-6 and IL-12 secretion and an increase of CXCL10 production in a manner that is independent of NRF2 and ATF3. We show that a treatment with neither mesaconate nor itaconate impairs IL-1ß secretion and inflammasome activation. In summary, our results identify mesaconate as an immunomodulatory metabolite in macrophages, which interferes to a lesser extent with cellular metabolism than itaconate.

VZV Infection of Primary Human Adrenal Cortical Cells Produces a Proinflammatory Environment without Cell Death.

Virus infection of adrenal glands can disrupt secretion of mineralocorticoids, glucocorticoids, and sex hormones from the cortex and catecholamines from the medulla, leading to a constellation of symptoms such as fatigue, dizziness, weight loss, nausea, and muscle and joint pain. Specifically, varicella zoster virus (VZV) can produce bilateral adrenal hemorrhage and adrenal insufficiency during primary infection or following reactivation. However, the mechanisms by which VZV affects the adrenal glands are not well-characterized. Herein, we determined if primary human adrenal cortical cells (HAdCCs) infected with VZV support viral replication and produce a proinflammatory environment. Quantitative PCR showed VZV DNA increasing over time in HAdCCs, yet no cell death was seen at 3 days post-infection by TUNEL staining or Western Blot analysis with PARP and caspase 9 antibodies. Compared to conditioned supernatant from mock-infected cells, supernatant from VZV-infected cells contained significantly elevated IL-6, IL-8, IL-12p70, IL-13, IL-4, and TNF-α. Overall, VZV can productively infect adrenal cortical cells in the absence of cell death, suggesting that these cells may be a potential reservoir for ongoing viral replication and proinflammatory cytokine production, leading to chronic adrenalitis and dysfunction.

Cytosolic Sensing of Intracellular Staphylococcus aureus by Mast Cells Elicits a Type I IFN Response That Enhances Cell-Autonomous Immunity.

Strategically located at mucosal sites, mast cells are instrumental in sensing invading pathogens and modulating the quality of the ensuing immune responses depending on the nature of the infecting microbe. It is believed that mast cells produce type I IFN (IFN-I) in response to viruses, but not to bacterial infections, because of the incapacity of bacterial pathogens to internalize within mast cells, where signaling cascades leading to IFN-I production are generated. However, we have previously reported that, in contrast with other bacterial pathogens, Staphylococcus aureus can internalize into mast cells and therefore could trigger a unique response. In this study, we have investigated the molecular cross-talk between internalized S. aureus and the human mast cells HMC-1 using a dual RNA sequencing approach. We found that a proportion of internalized S. aureus underwent profound transcriptional reprogramming within HMC-1 cells to adapt to the nutrients and stress encountered in the intracellular environment and remained viable. HMC-1 cells, in turn, recognized intracellular S. aureus via cGMP-AMP synthase-STING-TANK-binding kinase 1 signaling pathway, leading to the production of IFN-I. Bacterial internalization and viability were crucial for IFN-I induction because inhibition of S. aureus internalization or infection with heat-killed bacteria completely prevented the production of IFN-I by HMC-1 cells. Feeding back in an autocrine manner in S. aureus-harboring HMC-1 cells and in a paracrine manner in noninfected neighboring HMC-1 cells, IFN-I promoted a cell-autonomous antimicrobial state by inducing the transcription of IFN-I-stimulated genes. This study provides unprecedented evidence of the capacity of mast cells to produce IFN-I in response to a bacterial pathogen.

A home-based exercise program for temporomandibular joint osteoarthritis: pain, functionality, and joint structure.

OBJECTIVES: Osteoarthritis (OA) is the most prevalent and disabling joint disease in the world. Temporomandibular joint (TMJ) exercise is a widely used treatment and could be a beneficial and long-term tool for treating TMJ OA. The present study aims to evaluate the effects of therapeutic exercise in the conservative treatment of TMJ OA. MATERIALS AND METHODS: A single-group experimental pre-post test was performed. We included patients who met the diagnostic criteria for TMJ OA. Outcome variables were pain intensity (visual analogue scale), functionality (Helkimo index), and structural changes (ultrasound). Follow-up periods were at months 1, 3, and 6. The intervention included a home-based program with thermotherapy, manual therapy, and therapeutic exercise during the entire follow-up period. RESULTS: We included 15 patients and 26 joints, all women with a median age of 57 years (range, 49-62 years). Median change in pain intensity on joint palpation, mouth opening, and at rest at the first month was 47.5 mm, 51 mm, and 60 mm, respectively, and 48 mm, 49.5 mm, and 42.5 mm, at six months (P=0.001). The Helkimo index showed significant improvement in medians from baseline severe dysfunction (17 points) to minimal dysfunction at three and six months (2 points) (P=0.001). Ultrasound showed improved disc position. CONCLUSION: This study demonstrated significant improvements in pain, function, and joint disc position and represents a valuable tool for the long-term treatment of patients with TMJ OA.

The emerging potential of microbiome transplantation on human health interventions.

The human microbiome has been the subject of intense research over the past few decades, in particular as a promising area for new clinical interventions. The microbiota colonizing the different body surfaces are of benefit for multiple physiological and metabolic processes of the human host and increasing evidence suggests an association between disturbances in the composition and functionality of the microbiota and several pathological conditions. This has provided a rationale for beneficial modulation of the microbiome. One approach being explored for modulating the microbiota in diseased individuals is transferring microbiota or microbiota constituents from healthy donors via microbiome transplantation. The great success of fecal microbiome transplantation for the treatment of Clostridioides difficile infections has encouraged the application of this procedure for the treatment of other diseases such as vaginal disorders via transplantation of vaginal microbiota, or of skin pathologies via the transplantation of skin microbiota. Microbiome modulation could even become a novel strategy for improving the efficacy of cancer therapies. This review discusses the principle, advantages and limitations of microbiome transplantation as well as different clinical contexts where microbiome transplantation has been applied.

Dysregulated Immunometabolism Is Associated with the Generation of Myeloid-Derived Suppressor Cells in Staphylococcus aureus Chronic Infection.

Myeloid-derived suppressor cells (MDSCs) are a compendium of immature myeloid cells that exhibit potent T-cell suppressive capacity and expand during pathological conditions such as cancer and chronic infections. Although well-characterized in cancer, the physiology of MDSCs in the infection setting remains enigmatic. Here, we integrated single-cell RNA sequencing (scRNA-seq) and functional metabolic profiling to gain deeper insights into the factors governing the generation and maintenance of MDSCs in chronic Staphylococcus aureus infection. We found that MDSCs originate not only in the bone marrow but also at extramedullary sites in S. aureus-infected mice. scRNA-seq showed that infection-driven MDSCs encompass a spectrum of myeloid precursors in different stages of differentiation, ranging from promyelocytes to mature neutrophils. Furthermore, the scRNA-seq analysis has also uncovered valuable phenotypic markers to distinguish mature myeloid cells from immature MDSCs. Metabolic profiling indicates that MDSCs exhibit high glycolytic activity and high glucose consumption rates, which are required for undergoing terminal maturation. However, rapid glucose consumption by MDSCs added to infection-induced perturbations in the glucose supplies in infected mice hinders the terminal maturation of MDSCs and promotes their accumulation in an immature stage. In a proof-of-concept in vivo experiment, we demonstrate the beneficial effect of increasing glucose availability in promoting MDSC terminal differentiation in infected mice. Our results provide valuable information of how metabolic alterations induced by infection influence reprogramming and differentiation of MDSCs.

The gammaherpesvirus 68 viral cyclin facilitates expression of LANA.

Gammaherpesviruses establish life-long infections within their host and have been shown to be the causative agents of devastating malignancies. Chronic infection within the host is mediated through cycles of transcriptionally quiescent stages of latency with periods of reactivation into detectable lytic and productive infection. The mechanisms that regulate reactivation from latency remain poorly understood. Previously, we defined a critical role for the viral cyclin in promoting reactivation from latency. Disruption of the viral cyclin had no impact on the frequency of cells containing viral genome during latency, yet it remains unclear whether the viral cyclin influences latently infected cells in a qualitative manner. To define the impact of the viral cyclin on properties of latent infection, we utilized a viral cyclin deficient variant expressing a LANA-beta-lactamase fusion protein (LANA::ßla), to enumerate both the cellular distribution and frequency of LANA gene expression. Disruption of the viral cyclin did not affect the cellular distribution of latently infected cells, but did result in a significant decrease in the frequency of cells that expressed LANA::ßla across multiple tissues and in both immunocompetent and immunodeficient hosts. Strikingly, whereas the cyclin-deficient virus had a reactivation defect in bulk culture, sort purified cyclin-deficient LANA::ßla expressing cells were fully capable of reactivation. These data emphasize that the γHV68 latent reservoir is comprised of at least two distinct stages of infection characterized by differential LANA expression, and that a primary function of the viral cyclin is to promote LANA expression during latency, a state associated with ex vivo reactivation competence.

The yawning gap between osteoporosis diagnosis and treatment after a fragility fracture in Mexico.

This study shows a diagnostic and therapeutic gap for osteoporosis in patients with fragility fractures of the hip, distal radius, and vertebrae. Patients with fragility fractures treated in Mexico fail to receive an osteoporosis diagnosis, referral, and follow-up treatment. The therapeutic gap is higher than reported in other countries. INTRODUCTION: Osteoporosis is a highly prevalent and disabling disease. While there is typically a gap between osteoporosis diagnosis and treatment after a fragility fracture, this gap has not been measured in Mexico. The study aimed to describe and quantify the gap between osteoporosis diagnosis and treatment after an incident fragility fracture. MATERIALS AND METHODS: A descriptive and 3-year retrospective chart review study was conducted on patients over the age of 50 with a diagnosis of an incident acute low-energy fracture of either the hip, distal radius, or vertebrae. RESULTS: We included 838 patients with a mean age of 76.3 ± 12.2 years. The sample was mostly women (665 participants, 79.4%); 589 (70.3%) had a hip fracture, 173 (20.6%) had a distal radius fracture, and 76 (9.1%) had a vertebral fracture. Only 28 (3.3%) had a previous diagnosis and were taking a pharmacological treatment for osteoporosis; 11 (1.3%) received their diagnosis while hospitalized. Immediately after the fracture, and 1 and 3 years later, 144 (17.1%), 71 (8.4%), and 96 (11.4%) respectively received a pharmacological treatment, 195 (23.2%), 65 (7.7%), and 45 (5.3%) supplementation, and 16 (1.9%), 16 (1.9%), and 21 (2.5%) a non-pharmacologic treatment. No significant differences in treatment prescriptions were found after a second or third fracture. CONCLUSION: The study quantifies the too high frequency of failure to diagnose and treat osteoporosis in patients with fragility fractures. Measures should be established to reduce the yawning gap between osteoporosis diagnosis and treatment after a fragility fracture.