SOFT TISSUE LOADS AT THE HUMAN KNEE DURING RUNNING AND CUTTING MANOEUVRES

Tensile forces on the ACL increase when the knee is in an extended posture and required to accommodate applied moments in flexion, varus, valgus and/or internal rotation. However, the loading of knee joint support structures during sporting actions that are related to non-contact injuries are largely unknown. We studied external loading of the knee during running, side-stepping and cross-over cutting in 10 male subjects under both pre-planned and unanticipated conditions. Soft tissue structures of the knee were exposed to high FE, VV and IE applied moments during the cutting tasks, especially when performed in the unanticipated condition. Whilst muscle activation could accommodate some of this applied load, soft tissue structures were particularly vulnerable during the cross-over cut task where the residual loads were high

THE EFFECT OF LOWER LIMB TRAINING ON MUSCULAR SUPPORT OF THE KNEE AND RISK OF ANTERIOR CRUCIATE LIGAMENT INJURY.

An intervention study was performed to investigate the effect of lower-limb training programs on knee muscle activation patterns and their potential to support the knee load during running and cutting manoeuvres. It is known that balance training can reduce ACL injury but the underlying mechanisms are unknown. The effects that strength training has on support for the knee joint during sporting manoeuvres are also not known. Analysis of activation levels and patterns of leg muscles during running, sidestepping and crossover-cutting manoeuvres prior to and following 12-week training programs revealed important results in terms of potential support of load on the ACL. Balance training increased co-contraction and supportive muscle activation patterns, as did the combination of machine and balance training to a lesser extent. The strength training programs tended to reduce co-contraction and were associated with changes which would lead to less stability of the knee during sporting manoeuvres. It is recommended that balance training should be implemented to reduce an athlete’s risk of ACL injury

Multiomics links global surfactant dysregulation with airflow obstruction and emphysema in COPD

RATIONALE: Pulmonary surfactant is vital for lung homeostasis as it reduces surface tension to prevent alveolar collapse and provides essential immune-regulatory and antipathogenic functions. Previous studies demonstrated dysregulation of some individual surfactant components in COPD. We investigated relationships between COPD disease measures and dysregulation of surfactant components to gain new insights into potential disease mechanisms. METHODS: Bronchoalveolar lavage proteome and lipidome were characterised in ex-smoking mild/moderate COPD subjects (n=26) and healthy ex-smoking (n=20) and never-smoking (n=16) controls using mass spectrometry. Serum surfactant protein analysis was performed. RESULTS: Total phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol, surfactant protein (SP)-B, SP-A and SP-D concentrations were lower in COPD versus controls (log2 fold change (log2FC) -2.0, -2.2, -1.5, -0.5, -0.7 and -0.5 (adjusted p<0.02), respectively) and correlated with lung function. Total phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol, SP-A, SP-B, SP-D, napsin A and CD44 inversely correlated with computed tomography small airways disease measures (expiratory to inspiratory mean lung density) (r= -0.56, r= -0.58, r= -0.45, r= -0.36, r= -0.44, r= -0.37, r= -0.40 and r= -0.39 (adjusted p<0.05)). Total phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol, SP-A, SP-B, SP-D and NAPSA inversely correlated with emphysema (% low-attenuation areas): r= -0.55, r= -0.61, r= -0.48, r= -0.51, r= -0.41, r= -0.31 and r= -0.34, respectively (adjusted p<0.05). Neutrophil elastase, known to degrade SP-A and SP-D, was elevated in COPD versus controls (log2FC 0.40, adjusted p=0.0390), and inversely correlated with SP-A and SP-D. Serum SP-D was increased in COPD versus healthy ex-smoking volunteers, and predicted COPD status (area under the curve 0.85). CONCLUSIONS: Using a multiomics approach, we demonstrate, for the first time, global surfactant dysregulation in COPD that was associated with emphysema, giving new insights into potential mechanisms underlying the cause or consequence of disease

Investigating macrophage-pathogen interactions in asthma

The pathobiont, Nontypeable Haemophilus influenzae (NTHi), colonises the airway of individuals with chronic respiratory disease and is particularly associated with severe, neutrophilic, steroid-resistant asthma. Although NTHi has been implicated in asthma, respiratory tract viral infections remain the main aetiological agent of asthma exacerbations. However, it is now becoming clear that the presence of potentially pathogenic bacteria, such as NTHi, are present in the airway prior to respiratory tract viral infections. The macrophage is the predominant immune cell in the airway, yet accumulating evidence suggests NTHi is able to infect and persist within macrophages, which are also a target of the influenza A virus (IAV). It is unclear whether NTHi infection and persistence modulates macrophage responses to respiratory tract viral infections.The aim of this thesis was to investigate modulation of macrophage gene expression during intracellular NTHi infection and how this interaction impacts on the response of these cells to subsequent infection with IAV. In addition, this thesis aimed to investigate transcriptomic alterations of NTHi during intracellular infection of macrophages, in order to identify mechanisms of persistence.To achieve these aims, dual RNASeq analysis of an NTHi-monocyte-derived macrophage (MDM) infection model was performed. Transcriptomic analysis of NTHi-infected MDM identified enrichment of macrophage intracellular immune response pathways. Use of WGCNA identified CASP4, PNRC1 and SGPP2 to be the central MDM genes in the gene module most significantly associated with NTHi infection. Despite activation of MDM innate immune responses, NTHi was still able to persist within these cells. NTHi adaptation to persistence was associated with modulation of bacterial pathways involved in metabolic and stress responses, and downregulation of NTHi ribosomal protein genes. However, validation of the top NTHi differentially expressed genes bioC, mepM and dps, found strain-dependent expression of NTHi genes. Validation of select macrophage intracellular immune response genes demonstrated conservation of the MDM transcriptomic response when challenged with additional clinical strains of NTHi. Furthermore, NTHi presence was detected by FISH in 56% of severe asthma bronchoalveolar lavage (BAL) samples, which was associated with increased neutrophil inflammation (p=0.0462) and asthma duration (p=0.0436). Elevated IL1B (p=0.0041), GBP1 (p=0.0477) and SGPP2 (p=0.0221) gene expression was detected in samples determined as NTHi positive compared to NTHi negative, indicating modulation of airway inflammation by NTHi. Adaptation of the MDM model to incorporate the IAV following NTHi infection resulted in further modulation of the infection process; IAV replication levels decreased (p=0.0049), whereas NTHi load increased (p=0.0313). Decreased IAV levels was suggested to be due to NTHi-mediated upregulation of macrophage anti-viral immunity, specifically the type I IFN pathway, prior to IAV infection. Increased NTHi presence was associated with transcriptomic changes in NTHi genes previously identified to be involved in NTHi adaptation to intracellular persistence, bioC and mepM. Consequently, NTHi-infected macrophages exhibited a sustained inflammatory response, compared to MDM infected with IAV-alone.The data in this thesis indicate the ability of NTHi to adapt in order to persist within macrophages, despite activation of macrophage intracellular immune response pathways. The subsequent modulation of IAV infection and NTHi colonisation during co-infection resulted in sustained macrophage inflammation that was not sufficient to completely clear either pathogen. Modulation of macrophage responses prior to and during bacterial-viral co-infection could have important implications for designing future studies to better our understanding of multiple host-pathogen interactions in the lung

Strain-dependent effects of Nontypeable Haemophilus influenzae (NTHi) on human macrophage function

Nontypeable Haemophilus influenzae (NTHi) is a heterogeneous respiratory tract pathogen implicated in opportunistic infections and exacerbations of chronic respiratory diseases, such as COPD and asthma. In these diseases, airway macrophages have impaired phagocytic ability, contributing to chronic airway colonisation by NTHi. It is unclear whether macrophage responses to NTHi are strain-dependent, highlighting a possible mechanism by which certain NTHi strains can persist within the airway. The aim of this work was to characterise macrophage responses following infection with different clinical strains of NTHi.Monocyte-derived macrophages (MDM) isolated from blood of healthy volunteers were infected with NTHi ST14 or ST201 for 6h, incubated with antibiotics for a further 18h, followed by inflammatory pathway analysis by PCR or ELISA. Measurement of NTHi hel gene expression demonstrated increased presence of ST14, compared to ST201 in MDM at 24h (p&lt;0.05). MDM expression of IFNß, TLR4 and TLR7 was not significantly different between strains. However, MDM expression of CXCL10, RIG-I and NFκB was induced significantly more by ST14 (p&lt;0.05). In contrast, levels of CXCL10 released into MDM supernatants did not differ between the two strains. However, MDM production of IL1ß, IL6 and IL8 was higher in response to ST14 infection compared to ST201 (p&lt;0.05).This work suggests that ST14 is more persistent in MDM than ST201, resulting in increased expression of inflammatory markers. These data indicate that MDM respond differently to different NTHi strains. Investigating these strain differences will increase our understanding of the role of NTHi in exacerbations of chronic respiratory diseas

The response of macrophages to Moraxella catarrhalis infection

Infection by certain bacterial species can predispose an individual to developing asthma and trigger asthmatic exacerbations. Moraxella catarrhalis is one such organism, yet there is little data on the innate immune responses to this pathogen. Alveolar macrophages are the predominant immune cell isolated from the airway and show phenotypic differences in health and asthma. Macrophages are crucial in the immune response by pathogen recognition receptor (PRR)mediated detection of organisms, release of pro-inflammatory mediators and presentation of antigens to other cells of the immune system to link the innate and adaptive immune response. The aim of this work was to investigate the response of macrophages to M.catarrhalis. Monocyte-derived macrophages (MDM) were exposed to M.catarrhalis for 2h, incubated with antiobiotics for 22h before analysis at 24h. The expression of PRRs were analysed by real time PCR. A significant increase of retinoic acid-inducible gene(RIG)I expression(p&lt;0.0001) was found; however, IFN-β was not detected. Conversely, expression of toll-like receptor (TLR)4 decreased(p=0.0003). Despite this, the release of IL-1β and IL-8 was detected in a dose-dependent manner by ELISA(p&lt;0.0001). The surface expression of antigen presentation molecules were analysed by flow cytometry and showed an upregulation of major histocompatibility complex (MHC)-II(p=0.002) and MR1(p=0.0015), but only a slight upregulation of MHC-I(p=0.0728). This work suggests that MDM respond to M.catarrhalis and act to induce further immune cell effector actions. Understanding the MDM response to M.catarrhalis will allow for future comparisons to determine differences between the phenotypically distinctive macrophages in health and asthma

Interrupting the conversation: implications for crosstalk between viral and bacterial infections in the asthmatic airway

Asthma is a chronic heterogeneous respiratory disease affecting 300 million people and is thought to be driven by different inflammatory endotypes influenced by a myriad of genetic and environmental factors. The complexity of asthma has rendered it challenging to develop preventative and disease modifying therapies and it remains an unmet clinical need.Whilst many factors have been implicated in asthma pathogenesis and exacerbations, evidence indicates a prominent role of respiratory viruses. However, advances in culture-independent detection methods and extensive microbial profiling of the lung, have also demonstrated a role for respiratory bacteria in asthma. In particular, airway colonization by the Proteobacteria species Nontypeable Haemophilus influenzae (NTHi) and Moraxella catarrhalis (Mcat) is associated with increased risk of developing recurrent wheeze and asthma in early life, poor clinical outcomes in established adult asthma and the development of more severe inflammatory phenotypes. Furthermore, emerging evidence indicates that bacterial-viral interactions may influence exacerbation risk and disease severity, highlighting the need to consider the impact chronic airway colonisation by respiratory bacteria has on influencing host responses to viral infection.In this review, we first outline the currently understood role of viral and bacterial infections in precipitating asthma exacerbations and discuss the underappreciated potential impact of bacteria virus crosstalk in modulating host responses. We discuss the mechanisms by which early life infection may predispose to asthma development. Finally, we consider how infection and persistent airway colonization may drive different asthma phenotypes, with a view to identifying pathophysiological mechanisms that may prove tractable to new treatment modalities

Review of the British Thoracic Society Winter Meeting 23 November 2022 23-25 November 2022.

The British Thoracic Society Winter Meeting at the QEII Centre in London provided the first opportunity for the respiratory community to meet and disseminate research findings face to face since the start of the COVID-19 pandemic. World-leading researchers from the UK and abroad presented their latest findings across a range of respiratory diseases. This article aims to represent the range of the conference and as such is written from the perspective of a basic scientist, a physiotherapist and two doctors. The authors reviewed showcase sessions plus a selection of symposia based on their personal highlights. Content ranged from exciting new developments in basic science to new and unpublished results from clinical trials, delivered by leading scientists from their fields including former deputy chief medical officer Professor Sir Jonathan Van-Tam and former WHO chief scientist Dr Soumya Swaminathan