Multiple Sclerosis-associated Bacterial Ligand 654.

BACKGROUND AND AIMS: Many endogenous and exogenous risk factors are associated with multiple sclerosis (MS), but recent studies suggest that microbiome-derived ligands, play a role in the disease process. The goal of this study was to characterize the cellular response elicited in human microglia upon treatment with IFN-ß and Fingolimod, two first line medications for the management of MS, and determine whether these treatments affect the response of microglial cells to an MS-associated bacterial ligand, Lipid 654. MATERIALS AND METHODS: HMC3 human microglial cells were treated with IFN-ß or Fingolimod. Cytokine secretion was evaluated using a multiplex system, and microglia polarization was assessed by flow cytometry. RESULTS: We observed that treatment with IFN-ß or Fingolimod induced differential secretion of various pro-inflammatory cytokines. Upon cell stimulation with Lipid 654, we observed that IFN-ß and Fingolimod decreased the secretion of M1-associated cytokines. Using flow cytometry, we observed that the decrease in inflammatory cytokine secretion was likely due to a containment of M1 phenotype of microglia after stimulation with Lipid 654. CONCLUSIONS: Our findings provide new clues of still unknown mechanisms of action of IFN-ß and Fingolimod in human microglia, which will prompt new avenues of research on the use of these therapies in the regulation of the inflammatory response in MS.

Slither Into the Heart: Salmonella Endocarditis Following Rattlesnake Meat Ingestion.

Salmonellae foodborne infections are a well described and documented entity, however cardiac complications of Salmonellae foodborne infections including infective endocarditis (IE) are rare. Here we present a case of infective endocarditis as a result of bacteremia caused by multiple species of Salmonella. The patient initially presented with chest pain, fever and altered mental status. Troponin and ECG were unremarkable. The patient was started on empiric antibiotics. Blood cultures grew Salmonella species serotype O&H. Transesophageal echocardiogram (TEE) confirmed aortic valve vegetation. Regional cultural practices suggested possible contamination attributed to ingestion of rattlesnake meat, a practice that has been previously described and well-established in various Hispanic folk practices. Upon further history taking, the patient was found to be regularly consuming dried rattlesnake meat preparations, a rather common practice in Chihuahua desert region. Surgery was not indicated, and the patient was treated with six weeks of antibiotics. This case presents an opportunity to gain insight into such a unique manifestation of Salmonellae, offering a potential facet of information for clinicians to better understand its presentation, susceptibility, and potential adverse outcomes.

Professional Development Track to Prepare Future Academic Clinicians.

Professional development is instrumental in the success of professionals and trainees in academic medicine. In response to medical student feedback requesting additional professional development opportunities, the Foster School of Medicine developed a distinction program, the Pathway for Preparing Academic Clinicians (PPAC), designed to deliver sought-after skill development and foundational knowledge in the three primary activities of academic medicine: medical education, research, and patient care. This distinction program addresses a curricular gap as identified by students and common to many UME curricula and also provides an opportunity for residency programs to identify student achievement within a pass/fail program.

Macrophage mediated recognition and clearance of Borrelia burgdorferi elicits MyD88-dependent and -independent phagosomal signals that contribute to phagocytosis and inflammation.

BACKGROUND: Macrophages play prominent roles in bacteria recognition and clearance, including Borrelia burgdorferi (Bb), the Lyme disease spirochete. To elucidate mechanisms by which MyD88/TLR signaling enhances clearance of Bb by macrophages, we studied wildtype (WT) and MyD88-/- Bb-stimulated bone marrow-derived macrophages (BMDMs). RESULTS: MyD88-/- BMDMs exhibit impaired uptake of spirochetes but comparable maturation of phagosomes following internalization of spirochetes. RNA-sequencing of infected WT and MyD88-/- BMDMs identified a large cohort of differentially expressed MyD88-dependent genes associated with re-organization of actin and cytoskeleton during phagocytosis along with several MyD88-independent chemokines involved in inflammatory cell recruitment. We computationally generated networks which identified several MyD88-dependent intermediate proteins (Rhoq and Cyfip1) that are known to mediate inflammation and phagocytosis respectively. CONCLUSION: Our findings show that MyD88 signaling enhances, but is not required, for bacterial uptake or phagosomal maturation and provide mechanistic insights into how MyD88-mediated phagosomal signaling enhances Bb uptake and clearance.

Early Impact of the COVID-19 Pandemic on Congenital Heart Surgery Programs Across the World: Assessment by a Global Multi-Societal Consortium.

The coronavirus disease 2019 (COVID-19) pandemic currently gripping the globe is impacting the entire health care system with rapidly escalating morbidities and mortality. Although the infectious risk to the pediatric population appears low, the effects on children with congenital heart disease (CHD) remain poorly understood. The closure of congenital heart surgery programs worldwide to address the growing number of infected individuals could have an unintended impact on future health for COVID-19-negative patients with CHD. Pediatric and congenital heart surgeons, given their small numbers and close relationships, are uniquely positioned to collectively assess the impact of the pandemic on surgical practice and care of children with CHD. We present the results of an international survey sent to pediatric and congenital heart surgeons characterizing the early impact of COVID-19 on the care of patients with CHD.

Evaluating the performance of a low-cost mobile phone attachable microscope in cervical cytology.

BACKGROUND: Cervical cancer remains a global health problem especially in remote areas of developing countries which have limited resources for cervical cancer screening. In this study, we evaluated the performance of a low-cost, smartphone attachable paper-based microscope when used for classifying images of cervical cytology. METHODS: Cervical cytology samples included: 10 Normal, 10 Low-grade squamous intraepithelial lesion (LSIL), 10 High-grade squamous intraepithelial lesion (HSIL), and 10 Malignant Pap Smears. The agreement between conventional microscopy vs. Foldscope imaging was calculated using a weighted kappa coefficient. A confusion matrix was created with three classes: Normal, LSIL, and HSIL/malignant, to evaluate the performance of the Foldscope by calculating the accuracy, sensitivity, and specificity. RESULTS: We observed a kappa statistic of 0.68 for the agreement. This translates into a substantial agreement between the cytological classifications by the Foldscope vs. conventional microscopy. The accuracy of the Foldscope was 80%, with a sensitivity and specificity of 85 and 90% for the HSIL/Mal category, 80 and 83.3%, for LSIL, and 70 and 96.7% for Normal. CONCLUSIONS: This study highlights the usefulness of the Foldscope in cervical cytology, demonstrating it has substantial agreement with conventional microscopy. Its use could improve cytologic interpretations in underserved areas and, thus, improve the quality of cervical cancer screening. Improvements in existing limitations of the device, such as ability to focus, could potentially increase its accuracy.

Personalized Medicine in Undergraduate Medical Education: a Spiral Learning Model.

Educational strategies to introduce medical students to scientific advances are needed as evidence continues to evolve regarding their clinical application in personalized medicine. Our overall project goal is to design an evidence-based, clinically relevant, personalized medicine curriculum spanning the 4 years of undergraduate medical education.

Characterisation of a New Human Alveolar Macrophage-Like Cell Line (Daisy).

PURPOSE: There is currently no true macrophage cell line and in vitro experiments requiring these cells currently require mitogenic stimulation of a macrophage precursor cell line (THP-1) or ex vivo maturation of circulating primary monocytes. In this study, we characterise a human macrophage cell line, derived from THP-1 cells, and compare its phenotype to the THP-1 cells. METHODS: THP-1 cells with and without mitogenic stimulation were compared to the newly derived macrophage-like cell line (Daisy) using microscopy, flow cytometry, phagocytosis assays, antigen binding assays and gene microarrays. RESULTS: We show that the cell line grows predominantly in an adherent monolayer. A panel of antibodies were chosen to investigate the cell surface phenotype of these cells using flow cytometry. Daisy cells expressed more CD11c, CD80, CD163, CD169 and CD206, but less CD14 and CD11b compared with mitogen-stimulated THP-1 cells. Unlike stimulated THP-1 cells which were barely able to bind immune complexes, Daisy cells showed large amounts of immune complex binding. Finally, although not statistically significant, the phagocytic ability of Daisy cells was greater than mitogen-stimulated THP-1 cells, suggesting that the cell line is more similar to mature macrophages. CONCLUSIONS: The observed phenotype suggests that Daisy cells are a good model of human macrophages with a phenotype similar to human alveolar macrophages.

Metformin in tuberculosis: beyond control of hyperglycemia.

Two global epidemics, diabetes mellitus (DM) and tuberculosis (TB), have converged making their control even more challenging. We herein have reviewed metformin's (MTF) effect on patients with active and latent TB, as well as discussed its newly discovered biological mechanisms in mycobacteria. Mounting evidence suggests that MTF provides better outcomes in TB patients, especially those with DM. The mechanisms by which MTF produces its benefits are multiple. Though metformin's potential has been proven in patients with DM, larger and more thorough clinical trials, in DM and non-DM-TB patients, need to be conducted. MTF could be added to the arsenal of anti-TB drugs, aiding in the goal of TB eradication worldwide.

Vitamin D modulates human macrophage response to Mycobacterium tuberculosis DNA.

Mycobacterium tuberculosis (Mtb) is a facultative intracellular pathogen that infects macrophages where it avoids elimination by interfering with host defense mechanisms, including phago-lysosome fusion. Endosomal Toll-like receptors (TLRs) generate Type I Interferons (IFNs), which are associated with active tuberculosis (TB). We aimed to explore if DNA from different Mtb lineages lead to differences in the inflammatory response of human monocytic/macrophage cells. THP-1 cells which express two inducible reporter constructs for interferons (IFNs) as well as for NF-κB, were stimulated via endosomal delivery of Mtb DNA as a nanocomplex with PEI. DNA from different Mtb phylogenetic lineages elicited differential inflammatory responses in human macrophages. An initial relatively weak IRF-mediated response to DNA from HN878 and H37Rv increased if the cells were pre-treated with Vitamin D (Vit D) for 72 h. RNAseq of THP-1 under different transformation conditions showed that pre-treatment with Vit D upregulated several TLR9 variants, as well as genes involved in inflammatory immune response to infection, immune cell activation, Type I IFN regulation, and regulation of inflammation. Vit D appears to be important in increasing low IRF responses to DNA from certain lineages of Mtb. Variations in the IRF-mediated response to DNA derived from different Mtb genotypes are potentially important in the pathogenesis of tuberculosis since Type I IFN responses are associated with active disease. The role of Vit D in these responses could also translate into future therapeutic approaches.

The role of phospholipase A2 in multiple Sclerosis: A systematic review and meta-analysis.

Phospholipases A2 (PLA2) are a diverse group of enzymes that cleave the fatty acids of membrane phospholipids. They play critical roles in pathogenesis of neurodegenerative diseases such as multiple sclerosis by enhancing oxidative stress and initiating inflammation. The levels of PLA2 activity in MS patients compared to controls and role of inhibiting PLA2 activity on severity scores in different experimental models are not comprehensively assessed in the light of varying evidence from published studies. The objective of this systematic review is to determine the association between PLA2 activity and multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). We performed a systematic review of six studies that assessed PLA2 activity in MS patients compared to controls and nine studies that assessed PLA2 activity in EAE. sPLA2 nor Lp-PLA2 activity were not increased in MS compared to controls in five of those six studies. A difference in sPLA2 activity was only found in a study that measured the enzyme activity in urine. However, inhibiting cPLA2 or sPLA2 led to lower clinical severity or no signs of EAE in mice, and a lower incidence of EAE lesions compared to animals without cPLA2 inhibition. These findings indicate that PLA2 appears to play a role in the pathogenesis of EAE.

Discrepancies in the evaluation of the safety of the human papillomavirus vaccine.

Despite being more than ten years since its introduction, global acceptance to the human papillomavirus (HPV) vaccine is still low. The immunogenetic background of the host, and HPV antigen recognition, are important in natural HPV infection, and should be taken into account in the understanding of adverse autoimmune reactions by the HPV vaccine in certain groups. There is no doubt of the benefit of vaccines in the reduction of the incidence of infectious diseases, and in the case of HPV, the prevention of persistent infection that would lead to cervical cancer. Side-effects, however, should be closely monitored and reported without any bias, to ensure that the benefits of vaccines outweigh the risks of adverse reactions. In this article we bring the attention on certain adverse effects of the vaccine against HPV that have not been well studied as they are not well defined. We also compare the different approaches on HPV vaccine policies regarding its adverse reactions in countries like Japan and Colombia, vs. the recommendations issued by the WHO.

Meta-analysis of the lung microbiota in pulmonary tuberculosis.

The lung microbiota has received less attention compared to other body sites, in part because its study carries special technological difficulties related to obtaining reliable samples as compared to other body niches. The limited number of studies on the sputum microbiota on TB patients and controls available so far have reported inconsistent, and sometimes, contradictory results. Aiming to clarify if changes in the lung microbiota composition are associated with pulmonary TB, we performed a meta-analysis of available data on microbiota of the lower respiratory tract in TB patients and healthy controls. Re-processing next generation sequencing data under uniform parameters and utilizing state-of-the-art bioinformatics analysis, we obtained distinct clusterings of microbiota between TB cases vs. controls across multiple studies. We identified Tumebacillus ginsengisoli, Propionibacterium acnes, Haemophilus parahaemolyticus as differentially abundant species signature in healthy controls while Caulobacter henricii, Actinomyces graevenitzii, Rothia mucilaginosa, in addition to Mycobacterium tuberculosis as differentially abundant species signature in TB cases, and described R. mucilaginosa as the anchoring species in a network of bacteria co-occurring with Mycobacterium tuberculosis (Mtb) infection.

Discrepancies in the evaluation of the safety of the human papillomavirus vaccine

Despite being more than ten years since its introduction, global acceptance to the human papillomavirus (HPV) vaccine is still low. The immunogenetic background of the host, and HPV antigen recognition, are important in natural HPV infection, and should be taken into account in the understanding of adverse autoimmune reactions by the HPV vaccine in certain groups. There is no doubt of the benefit of vaccines in the reduction of the incidence of infectious diseases, and in the case of HPV, the prevention of persistent infection that would lead to cervical cancer. Side-effects, however, should be closely monitored and reported without any bias, to ensure that the benefits of vaccines outweigh the risks of adverse reactions. In this article we bring the attention on certain adverse effects of the vaccine against HPV that have not been well studied as they are not well defined. We also compare the different approaches on HPV vaccine policies regarding its adverse reactions in countries like Japan and Colombia, vs. the recommendations issued by the WHO.

IFNγ Enhances CD64-Potentiated Phagocytosis of Treponema pallidum Opsonized with Human Syphilitic Serum by Human Macrophages.

Syphilis is a multi-stage, sexually transmitted disease caused by the spirochete Treponema pallidum (Tp). Considered broadly, syphilis can be conceptualized as a dualistic process in which spirochete-driven inflammation, the cause of clinical manifestations, coexists to varying extents with bacterial persistence. Inflammation is elicited in the tissues, along with the persistence of spirochetes to keep driving a robust immune response while evading host defenses; this duality is best exemplified during the florid, disseminated stage called secondary syphilis (SS). SS lesions typically contain copious amounts of spirochetes along with a mixed cellular infiltrate consisting of CD4+ T cells, CD8+ T cells, NK cells, plasma cells, and macrophages. In the rabbit model, Tp are cleared by macrophages via antibody-mediated opsonophagocytosis. Previously, we demonstrated that human syphilitic serum (HSS) promotes efficient uptake of Tp by human monocytes and that opsonophagocytosis of Tp markedly enhances cytokine production. Herein, we used monocyte-derived macrophages to study Tp-macrophage interactions ex vivo. In the absence of HSS, monocyte-derived macrophages internalized low numbers of Tp and secreted little cytokine (e.g., TNF). By contrast, these same macrophages internalized large numbers of unopsonized Borrelia burgdorferi and secreted robust levels of cytokines. Maturation of macrophages with M-CSF and IFNγ resulted in a macrophage phenotype with increased expression of HLA-DR, CD14, inducible nitric oxide synthase, TLR2, TLR8, and the Fcγ receptors (FcγR) CD64 and CD16, even in the absence of LPS. Importantly, IFNγ-polarized macrophages resulted in a statistically significant increase in opsonophagocytosis of Tp accompanied by enhanced production of cytokines, macrophage activation markers (CD40, CD80), TLRs (TLR2, TLR7, TLR8), chemokines (CCL19, CXCL10, CXCL11), and TH1-promoting cytokines (IL-12, IL-15). Finally, the blockade of FcγRs, primarily CD64, significantly diminished spirochetal uptake and proinflammatory cytokine secretion by IFNγ-stimulated macrophages. Our ex vivo studies demonstrate the importance of CD64-potentiated uptake of opsonized Tp and suggest that IFNγ-activated macrophages have an important role in the context of early syphilis. Our study results also provide an ex vivo surrogate system for use in future syphilis vaccine studies.

MyD88 in Mycobacterium tuberculosis infection.

MyD88 adaptor protein mediates numerous biologically important signal transduction pathways in innate immunity. MyD88 signaling fosters bacterial containment and is necessary to raise an adequate innate and acquired immune response to Mycobacterium tuberculosis (Mtb). The phagosome is a crucial cellular location not only for Mtb replication, but it is also where components of the Myddosome and inflammasome are recruited. Besides its function as a TLR-adaptor protein, MyD88 may help stabilizing cytosolic receptors that are recruited to the phagosome. MyD88 plays a critical role not only in the generation of an inflammatory response, but also in inducing regulatory signals to prevent excessive inflammation and cellular damage in the lung.

Pregnane X Receptor Regulates Pathogen-Induced Inflammation and Host Defense against an Intracellular Bacterial Infection through Toll-like Receptor 4.

The nuclear pregnane X receptor (PXR) plays a central role in regulating xenobiotic metabolism. We now report a novel role for PXR as a critical negative regulator of innate immunity after infection. Pxr(-/-) mice exhibited remarkably elevated pro-inflammatory cytokine and chemokine production following infection with Listeria monocytogenes (Lm). Despite the more robust innate immune response, Pxr(-/-) mice were highly susceptible to Lm infection. Surprisingly, disruption of the Toll-like receptor 4 (TLR4) but not TLR2 signaling restored the inflammation to normal levels and the ability to clear Lm in Pxr(-/-) mice. Mechanistically, the heightened inflammation in Pxr(-/-) mice resulted in the death of inflammatory monocytes that led to the enhanced susceptibility to Lm infection. These data demonstrated that PXR regulated pathogen-induced inflammation and host defense against Lm infection through modulating the TLR4 pathway. In summary, we discovered an apical role for PXR in regulating innate immunity. In addition, we uncovered a remarkable negative impact of the TLR4 pathway in controlling the quality of the inflammatory response and host defense against a gram-positive bacterial infection.

Dysbiosis and Immune Dysregulation in Outer Space.

In space, the lifestyle, relative sterility of spaceship and extreme environmental stresses, such as microgravity and cosmic radiation, can compromise the balance between human body and human microbiome. An astronaut's body during spaceflight encounters increased risk for microbial infections and conditions because of immune dysregulation and altered microbiome, i.e. dysbiosis. This risk is further heightened by increase in virulence of pathogens in microgravity. Health status of astronauts might potentially benefit from maintaining a healthy microbiome by specifically managing their diet on space in addition to probiotic therapies. This review focuses on the current knowledge/understanding of how spaceflight affects human immunity and microbiome.