ß-glucans from Agaricus bisporus mushroom products drive Trained Immunity.

Introduction: Macrofungi, such as edible mushrooms, have been used as a valuable medical resource for millennia as a result of their antibacterial and immuno-modulatory components. Mushrooms contain dietary fibers known as ß-glucans, a class of polysaccharides previously linked to the induction of Trained Immunity. However, little is known about the ability of mushroom-derived ß-glucans to induce Trained Immunity. Methods & results: Using various powdered forms of the white button mushroom (Agaricus bisporus), we found that mouse macrophages pre-treated with whole mushroom powder (WMP) displayed enhanced responses to restimulation with TLR ligands, being particularly sensitive to Toll-like receptor (TLR)-2 stimulation using synthetic lipopeptides. This trained response was modest compared to training observed with yeast-derived ß-glucans and correlated with the amount of available ß-glucans in the WMP. Enriching for ß-glucans content using either a simulated in-vitro digestion or chemical fractionation retained and boosted the trained response with WMP, respectively. Importantly, both WMP and digested-WMP preparations retained ß-glucans as identified by nuclear magnetic resonance analysis and both displayed the capacity to train human monocytes and enhanced responses to restimulation. To determine if dietary incorporation of mushroom products can lead to Trained Immunity in myeloid cells in vivo, mice were given a regimen of WMP by oral gavage prior to sacrifice. Flow cytometric analysis of bone-marrow progenitors indicated alterations in hematopoietic stem and progenitor cells population dynamics, with shift toward myeloid-committed multi-potent progenitor cells. Mature bone marrow-derived macrophages derived from these mice displayed enhanced responses to restimulation, again particularly sensitive to TLR2. Discussion: Taken together, these data demonstrate that ß-glucans from common macrofungi can train innate immune cells and could point to novel ways of delivering bio-available ß-glucans for education of the innate immune system.

Recognition of yeast ß-glucan particles triggers immunometabolic signaling required for trained immunity.

Fungal ß-glucans are major drivers of trained immunity which increases long-term protection against secondary infections. Heterogeneity in ß-glucan source, structure, and solubility alters interaction with the phagocytic receptor Dectin-1 and could impact strategies to improve trained immunity in humans. Using a panel of diverse ß-glucans, we describe the ability of a specific yeast-derived whole-glucan particle (WGP) to reprogram metabolism and thereby drive trained immunity in human monocyte-derived macrophages in vitro and mice bone marrow in vivo. Presentation of pure, non-soluble, non-aggregated WGPs led to the formation of the Dectin-1 phagocytic synapse with subsequent lysosomal mTOR activation, metabolic reprogramming, and epigenetic rewiring. Intraperitoneal or oral administration of WGP drove bone marrow myelopoiesis and improved mature macrophage responses, pointing to therapeutic and food-based strategies to drive trained immunity. Thus, the investment of a cell in a trained response relies on specific recognition of ß-glucans presented on intact microbial particles through stimulation of the Dectin-1 phagocytic response.

Negative Regulation of Innate Immune Signaling by Components of the Button Mushroom Agaricus bisporus.

SCOPE: Mushrooms are valued as an edible and medical resource for millennia. As macrofungi, they possess conserved molecular components recognized by innate immune cells like macrophages, yet unlike pathogenic fungi, they do not trigger the immune system in the same way. That these well-tolerated foods both avoid immuno-surveillance and have positive health benefits, highlights the dearth of information on the interactions of mushroom-derived products with the immune system. METHODS AND RESULTS: Using powders produced from the common white button mushroom, Agaricus bisporus, it is observed that pre-treatment of mouse and human macrophages with mushroom powders attenuates innate immune signaling triggered by microbial ligands like LPS and  ß-glucans, including NFκB activation and pro-inflammatory cytokine production. This effect of mushroom powders is observed at lower doses of TLR ligands, suggesting a model of competitive inhibition whereby mushroom compounds bind and occupy innate immune receptors, precluding activation by microbial stimuli. This effect is preserved following simulated digestion of the powders. Moreover, in vivo delivery of mushroom powders attenuates the development of colitis in a DSS-mouse model. CONCLUSION: This data highlights an important anti-inflammatory role for powdered A. bisporus mushrooms, which can be further utilized to develop complementary approaches to modulate chronic inflammation and disease.

von Willebrand factor links primary hemostasis to innate immunity.

The plasma multimeric glycoprotein von Willebrand factor (VWF) plays a critical role in primary hemostasis by tethering platelets to exposed collagen at sites of vascular injury. Recent studies have identified additional biological roles for VWF, and in particular suggest that VWF may play an important role in regulating inflammatory responses. However, the molecular mechanisms through which VWF exerts its immuno-modulatory effects remain poorly understood. In this study, we report that VWF binding to macrophages triggers downstream MAP kinase signaling, NF-κB activation and production of pro-inflammatory cytokines and chemokines. In addition, VWF binding also drives macrophage M1 polarization and shifts macrophage metabolism towards glycolysis in a p38-dependent manner. Cumulatively, our findings define an important biological role for VWF in modulating macrophage function, and thereby establish a novel link between primary hemostasis and innate immunity.

An Army Marches on Its Stomach: Metabolic Intermediates as Antimicrobial Mediators in Mycobacterium tuberculosis Infection.

The cells of the immune system are reliant on their metabolic state to launch effective responses to combat mycobacterial infections. The bioenergetic profile of the cell determines the molecular fuels and metabolites available to the host, as well as to the bacterial invader. How cells utilize the nutrients in their microenvironment-including glucose, lipids and amino acids-to sustain their functions and produce antimicrobial metabolites, and how mycobacteria exploit this to evade the immune system is of great interest. Changes in flux through metabolic pathways alters the intermediate metabolites present. These intermediates are beginning to be recognized as key modulators of immune signaling as well as direct antimicrobial effectors, and their impact on tuberculosis infection is becoming apparent. A better understanding of how metabolism impacts immunity to Mycobacterium tuberculosis and how it is regulated and thus can be manipulated will open the potential for novel therapeutic interventions and vaccination strategies.

Mycobacterium tuberculosis Limits Host Glycolysis and IL-1ß by Restriction of PFK-M via MicroRNA-21.

Increased glycolytic metabolism recently emerged as an essential process driving host defense against Mycobacterium tuberculosis (Mtb), but little is known about how this process is regulated during infection. Here, we observe repression of host glycolysis in Mtb-infected macrophages, which is dependent on sustained upregulation of anti-inflammatory microRNA-21 (miR-21) by proliferating mycobacteria. The dampening of glycolysis by miR-21 is mediated through targeting of phosphofructokinase muscle (PFK-M) isoform at the committed step of glycolysis, which facilitates bacterial growth by limiting pro-inflammatory mediators, chiefly interleukin-1ß (IL-1ß). Unlike other glycolytic genes, PFK-M expression and activity is repressed during Mtb infection through miR-21-mediated regulation, while other less-active isoenzymes dominate. Notably, interferon-γ (IFN-γ), which drives Mtb host defense, inhibits miR-21 expression, forcing an isoenzyme switch in the PFK complex, augmenting PFK-M expression and macrophage glycolysis. These findings place the targeting of PFK-M by miR-21 as a key node controlling macrophage immunometabolic function.

High-dose testosterone and dehydroepiandrosterone induce cardiotoxicity in rats: Assessment of echocardiographic, morphologic, and oxidative stress parameters.

The aim of this study is to assess cardiotoxic effect of testosterone (TES) and dehydroepiandrosterone (DHEA) in Sprague Dawley rats. We compared the impact of subacute (14 days) and subchronic (90 days) administration of suprapharmacologic doses of TES and DHEA on body weight, locomotor activity, muscle strength, echocardiographic parameters, heart histopathology, and oxidative stress markers with the control group. Testosterone (10, 30, and 100 mg/100 g body weight) and DHEA (10 mg/100 g body weight) administration decreased the body weights and locomotor activity (p < 0.05), and the combination of both increased muscle strength (p < 0.05) in rats. In our histopathological evaluation, misshapen cell nuclei, disorganized myocardial fibers, and leukocytic infiltrates were observed in high-dose TES (100 mg/100 g)-treated rats, especially on day 14. On day 90, mild changes such as misshapen cell nuclei, disorganized myocardial fibers, and leukocytic infiltrates were observed in TES and DHEA-treated groups. According to our echocardiographic study on day 14 and day 90, TES, especially at high doses, induced increase in left ventricular posterior wall diameter and ejection fraction (p < 0.05). In this study, blood oxidative stress marker malondialdehyde was increased slightly but not significantly in TES and DHEA groups. On the other hand, antioxidant enzymes such as SOD and glutathione peroxidase (GSH-Px) levels were slightly but not significantly increased in TES and DHEA groups. These data demonstrate that the potential risk to cardiac health due to exogenous androgen use may be related to oxidative stress in rats.

Primary middle-ear lymphoma in a child.

The case of a five year old boy who presented with a lower motor neurone facial nerve palsy secondary to primary non-Hodgkin's lymphoma (NHL) of the middle ear is discussed. Any child who presents with a facial nerve palsy and conductive hearing loss requires thorough evaluation to exclude the possibility of temporal bone malignancy.

An unusual case of external ear inflammation caused by sarcoidosis.

Inflammation of the pinna can occur in conjunction with polychondritis and otitis externa. We describe a case of pinneal inflammation that proved to be sarcoidosis, and we discuss the otolaryngologic manifestations of sarcoidosis.

Biomarkers Predict Relapse in Granulomatosis with Polyangiitis.

Granulomatosis with polyangiitis (GPA) is a small blood vessel vasculitic disorder with a high mortality rate if undiagnosed or treated inadequately. Disease relapse is a key feature of this disease and early identification of relapse episodes is very important in limiting end-organ damage. The advent of indirect immunofluorescence to detect antineutrophil cytoplasmic antibody (ANCA) with specific reactivity against the enzyme proteinase-3 (PR3) has been very useful in the diagnosis of GPA but is less helpful in predicting relapse. Indeed, up to date no satisfactory biomarker has been identified that can reliably predict relapse. This study assessed the probability of the occurrence of a relapse when a change was noted in a range of commonly used laboratory tests. These tests included levels of C-reactive protein (CRP), anti-PR3 antibodies, ANCA titre, and the neutrophil count. A group of 30 GPA patients with a total of 66 relapse episodes was investigated and a novel clinical yield score was devised. When a combined rise in CRP, anti-PR3 antibodies, and neutrophil count was observed in the 6-month period before a relapse event, 59% of patient relapses could be predicted. Monitoring changes in this set of parameters helps identify disease relapse.

Tracheal amyloidosis-an unusual cause of stridor.

Amyloidosis confined to the trachea is an exceedingly rare entity. We describe the case of a 63-year-old man who presented with a history of dysphonia and stridor. Rigid bronchoscopy revealed a segment of abnormal tissue at the midtracheal level, resembling granulation tissue. A stent was placed in an attempt to secure the patient's airway, which was >50% narrowed. Although the patient's stridor disappeared completely, 5 days postoperatively it recurred, worsening within hours. Emergency bronchoscopy revealed that the tracheal stent was almost completely obstructed with amyloid and granulation tissue, despite high-dose steroid therapy, and had to be removed. Tracheostomy was performed to bypass the diseased trachea. We also highlight some of the problems encountered with tracheal stenting in benign tracheal disease.

Left internal mammary artery use in patients with poor left ventricular ejection fraction: a propensity-matched analysis of mid-term survival.

We aimed to determine whether the use of left internal mammary artery (LIMA) to the left anterior descending (LAD) artery during coronary artery bypass grafting (CABG) confers an improved survival benefit to patients with an impaired preoperative left ventricular ejection fraction (LVEF). Between April 1997 and March 2004, 7198 consecutive patients underwent first time CABG to the LAD. There were 627 patients who had an LVEF <30% and of these, 548 patients (87.4%) received a LIMA graft, while 79 patients (12.6%) did not. A propensity-matched analysis was performed to provide matched cohorts for analysis of deaths occurring over time, which were described using Kaplan-Meier techniques. Propensity-matching produced two cohorts of 77 patients with or without the use of LIMA. Patient characteristics were reasonably matched between the groups. Forty-six (29.9%) deaths occurred in the propensity-matched groups. Freedom from death in patients with LIMA used at 4-years was 77.1%, compared with 60.7% for the patients with no LIMA used (P=0.026). The use of the LIMA as a bypass conduit is not contraindicated in patients with a poor preoperative LVEF. The usage of LIMA markedly improves survival.

Reexploration for bleeding after coronary artery bypass surgery: risk factors, outcomes, and the effect of time delay.

BACKGROUND: We aimed to identify risk factors for reexploration for bleeding after surgical revascularization in our practice. We also looked at the impact of resternotomy and the effect of time delay on mortality and other in-hospital outcomes. METHODS: In all, 2,898 consecutive patients undergoing coronary artery bypass grafting between April 1999 and March 2002 were retrospectively analyzed from our cardiac surgery registry. Multivariate logistic regression analysis was used to identify risk factors for reexploration for bleeding. To assess the effect of preoperative aspirin and heparin, reexploration patients were propensity matched with unique patients not requiring reexploration. We carried out a casenote review to ascertain the timing and causes for bleeding in patients undergoing resternotomy. RESULTS: Eighty-nine patients (3.1%) underwent reexploration for bleeding. Multivariate analysis revealed smaller body mass index (p = 0.003), nonelective surgery (p = 0.022), 5 or more distal anastomoses (p = 0.035), and increased age (p = 0.041) to have increased risks. Propensity-matched analysis showed that preoperative use of aspirin (p = 0.004) and heparin (p = 0.001) were associated with increased risk in the on-pump coronary surgery group only. Patients requiring resternotomy had a significantly greater need for inotropic agents (p < 0.001), and longer intensive care unit stay (p < 0.001) and postoperative stay (p < 0.001) than their propensity-matched controls. However, there was no significant difference in the mortality rate. Adverse outcomes were significantly higher when patients waited more than 12 hours after return to the intensive care unit for resternotomy. CONCLUSIONS: Risk factors for reexploration for bleeding after coronary artery bypass grafting include older age, smaller body mass index, nonelective cases, and 5 or more distal anastomoses. Preoperative aspirin and heparin were risk factors for the on-pump coronary artery surgery group. Patients needing reexploration are at higher risk of complications if the time to reexploration is prolonged. Policies that promote early return to the operating theater for reexploration should be encouraged.