Structural associations of symptomatic knee osteoarthritis

Objective Structural changes of osteoarthritis (OA) may occur in the absence of pain. In this study, we aimed to identify histopathologic features that are associated with symptomatic knee OA. Methods Medial tibial plateaus and synovium samples were obtained at the time of total knee replacement (TKR) surgery for OA (advanced OA group) or were obtained postmortem from subjects who had not sought medical attention for knee pain during the last year of life (non-OA control group). To identify features of OA, we compared the patients with advanced OA with the age-matched non-OA controls (n = 26 per group). To identify OA features associated with symptoms, we compared two additional groups of subjects who were matched for severity of chondropathy (n = 29 per group): patients undergoing TKR for symptomatic OA (symptomatic chondropathy group) and postmortem subjects with similar severity of chondropathy who were asymptomatic during the last year of life (asymptomatic chondropathy group). The histologic features of the samples were graded, and immunoreactivities for macrophages (CD68) and nerve growth factor (NGF) in the synovium were quantified. The cellular localization of synovial NGF was determined by double immunofluorescence analysis. Results Advanced OA cases displayed more severe changes in the synovium (synovitis, increased synovial NGF, and CD68-immunoreactive macrophages) and cartilage (loss of cartilage surface integrity, loss of proteoglycan, tidemark breaching, and alterations in chondrocyte morphology) than did the non-OA controls. Synovial NGF was localized predominantly to fibroblasts and to some macrophages. The symptomatic chondropathy group displayed greater levels of synovitis, synovial NGF, and loss of cartilage integrity, in addition to alterations in chondrocyte morphology, than did the asymptomatic chondropathy group (P < 0.05 for each comparison). Conclusion Synovitis, increased synovial NGF, alterations in chondrocyte morphology, and loss of cartilage integrity are features of knee OA that may be associated with symptoms

Blocking the tropomyosin receptor kinase A (TrkA) receptor inhibits pain behaviour in two rat models of osteoarthritis

Objectives: Tropomyosin receptor kinase A (TrkA) mediates nociceptor sensitisation by nerve growth factor (NGF), but it is unknown whether selective TrkA inhibition will be an effective strategy for treating osteoarthritis (OA) pain. We determined the effects of a TrkA inhibitor (AR786) on pain behaviour, synovitis and joint pathology in two rat OA models. Methods: Knee OA was induced in rats by intraarticular monosodium-iodoacetate (MIA) injection or meniscal transection (MNX) and compared with saline injected or sham-operated controls. Pain behaviour was assessed as weight-bearing asymmetry and paw withdrawal threshold to punctate stimulation. Oral doses (30 mg/kg) of AR786 or vehicle were administered twice daily in either preventive (day −1 to –27) or treatment (day 14–28) protocols. Effect maintenance was evaluated for 2 weeks after treatment discontinuation. Alterations in knee structure (cartilage, subchondral bone and synovium) were examined by macroscopic visualisation of articular surfaces and histopathology. Results: Preventive AR786 treatment inhibited pain behaviour development and therapeutic treatment attenuated established pain behaviour. Weight-bearing asymmetry increased 1 week after treatment discontinuation, but remained less than in vehicle- treated arthritic rats, whereas paw withdrawal thresholds returned to levels of untreated rats within 5 days of treatment discontinuation. AR786 treatment reduced MIA-induced synovitis and did not significantly affect osteochondral pathology in either model. Conclusions: Blocking NGF activity by inhibiting TrkA reduced pain behaviour in two rat models of OA. Analgesia was observed both using preventive and treatment protocols, and was sustained after treatment discontinuation. Selective inhibitors of TrkA therefore hold potential for OA pain relief

Targeting the D-series resolvin receptor system for the treatment of osteoarthritic pain

Objective: Pain is a major symptom of osteoarthritis (OA); current analgesics either do not offer adequate pain relief or are associated with serious side effects. Herein we have investigated the therapeutic potential of targeting the resolvin receptor system to modify OA pain and pathology. Methods: Gene expression of two resolvin receptors (ALX and ChemR23) was quantified in synovia and medial tibial plateau collected from patients at joint replacement for OA. Two models of OA joint pain were used for mechanistic studies. Gene expression in the periphery and CNS were quantified. Effects of exogenous administration of the D-series resolvin precursor 17(R)-hydroxy Docosahexaenoic Acid (17(R)-HDoHE on pain behaviour, joint pathology, spinal microglia and astroglyosis were quantified. Plasma levels of relevant lipids, resolvin D2, 17R-HDoHE and arachidonic acid was determined in rats using LC-MS-MS. Results: There was a positive correlation between resolvin receptor and IL6 expression in human OA synovia and medial tibial plateau. In the rat, synovia gene expression of ALX was positively correlated with IL1β, TNFα and COX2. Treatment with 17(R)-HDoHE reversed established pain behaviour in two models of OA pain, but not joint pathology. This was associated with a significant elevation in plasma levels of resolvin D2 and a significant reduction in astrogliosis in the spinal cord in the MIA model. Conclusion: Our preclinical data demonstrate robust analgesics effects of activating the D series resolvin pathways in two different animal models of OA. Our data support a predominant central mechanism of action in this clinically relevant model of OA pain

Robust anti-nociceptive effects of MAG lipase inhibition in a model of osteoarthritis pain

BACKGROUND AND PURPOSE: Chronic pain is often a symptom of knee osteoarthritis (OA) for which current analgesics are either inadequate, or are associated with serious side effects. The endocannabinoid system may offer alternative targets for pain-relief. We evaluated the effects of a potent and selective MAG lipase inhibitor (MJN110) on OA pain behaviour, spinal mechanisms of action and joint histopathology in the rat. Experimental approach: Intra-articular injection of monosodium iodoacetate (MIA) models OA pain and mimics clinical joint pathology. Effects of MJN110 on MIA-induced weight bearing asymmetry and lowered paw withdrawal thresholds (PWTs), changes in spinal gene expression and brain levels of relevant lipids were determined. Key results: Acute MJN110 (5 mg·kg−1) significantly reversed MIA induced weight bearing asymmetry (MIA /vehicle: 68 ± 6g; MIA /MJN110: 35 ± 4g, p<0.05) and lowered ipsilateral PWTs (MIA /vehicle: 7 ± 0.8g; MIA /MJN110: 11 ± 0.6g, p<0.05), via both CB1 and CB2 receptors. Repeated treatment with MJN110 (5 mg·kg−1) resulted in anti-nociceptive tolerance. A lower dose of MJN110 (1 mg·kg−1) acutely inhibited pain behaviour, which was maintained for one week of repeated administration, but had no effect on joint histology. MJN110 significantly inhibited expression of MPGES1 (p<0.05) in the ipsilateral dorsal horn of the spinal cord of MIA rats, compared to vehicle treated MIA rats. Both doses of MJN110 significantly elevated brain levels of the endocannabinoid 2-AG. Conclusions and Implications: Our data support the further investigation of the therapeutic potential of MAG lipase inhibitors for the treatment of OA pain

A novel hybrid promoter responsive to pathophysiological and pharmacological regulation

The aim of this study was to construct a promoter containing DNA motifs for an endogenous transcription factor associated with inflammation along with motifs for pharmacological regulation factors. We demonstrate in transfected cells that expression of a gene of interest is induced by hypoxic conditions or through pharmacological induction, and also show pharmacological repression. In vivo studies utilised electroporation of plasmid to mouse paws, a delivery method shown to be effective by bioluminescence imaging. For gene therapy, the promoter was used to drive expression of IL-1Ra in a paw inflammation model with therapeutic effect observed which was further enhanced when the promoter was additionally induced with a pharmacological activator. One of the most important observations from this study was that promoter induction by hypoxia or inflammation could be prevented by the pharmacological repressor in the absence of doxycycline. These studies demonstrate that hybrid promoters enable pharmacological adjustment to the pathophysiological level of gene expression and, importantly, that they allow termination of gene expression even in the presence of pathophysiological stimuli

Asthma caused by occupational exposures is common – A systematic analysis of estimates of the population-attributable fraction

<p>Abstract</p> <p>Background</p> <p>The aim of this paper is to highlight emerging data on occupational attributable risk in asthma. Despite well documented outbreaks of disease and the recognition of numerous specific causal agents, occupational exposures previously had been relegated a fairly minor role relative to other causes of adult onset asthma. In recent years there has been a growing recognition of the potential importance of asthma induced by work-related exposures</p> <p>Methods</p> <p>We searched Pub Med from June 1999 through December 2007. We identified six longitudinal general population-based studies; three case-control studies and eight cross-sectional analyses from seven general population-based samples. For an integrated analysis we added ten estimates prior to 1999 included in a previous review.</p> <p>Results</p> <p>The longitudinal studies indicate that 16.3% of all adult-onset asthma is caused by occupational exposures. In an overall synthesis of all included studies the overall median PAR value was 17.6%.</p> <p>Conclusion</p> <p>Clinicians should consider the occupational history when evaluating patients in working age who have asthma. At a societal level, these findings underscore the need for further preventive action to reduce the occupational exposures to asthma-causing agents.</p

Factors affecting turnaround time of SARS-CoV-2 sequencing for inpatient infection prevention and control decision making: Analysis of data from the COG-UK HOCI study

Background Barriers to rapid return of sequencing results can affect the utility of sequence data for infection prevention and control decisions. Aim To undertake a mixed-methods analysis to identify challenges sites faced in achieving a rapid turnaround time (TAT) in the COG-UK Hospital-Onset COVID-19 Infection (COG-UK HOCI) study. Methods For the quantitative analysis, timepoints relating to different stages of the sequencing process were extracted from both the COG-UK HOCI dataset and surveys of study sites. Qualitative data relating to the barriers and facilitators to achieving rapid TAT were included from thematic analysis. Findings The overall TAT, from sample collection to receipt of sequence report by infection control teams, varied between sites (median 5.1 days, range 3.0 – 29.0 days). Most variation was seen between reporting of a positive COVID-19 PCR result to sequence report generation (median 4.0 days, range 2.3 – 27.0 days). On deeper analysis, most of this variability was accounted for by differences in the delay between the COVID-19 PCR result and arrival of the sample at the sequencing laboratory (median 20.8 hours, 16.0 – 88.7 hours). Qualitative analyses suggest closer proximity of sequencing labs to diagnostic labs, increased staff flexibility and regular transport times facilitated a shorter TAT. Conclusion Integration of pathogen sequencing into diagnostic laboratories may help improve sequencing TAT to allow sequence data to be of tangible value to infection control practice. Adding a quality control step upstream to increase capacity further down the workflow may also optimise TAT if lower quality samples are removed earlier on

Effectiveness of rapid SARS-CoV-2 genome sequencing in supporting infection control for hospital-onset COVID-19 infection : multicenter, prospective study

Background: Viral sequencing of SARS-CoV-2 has been used for outbreak investigation, but there is limited evidence supporting routine use for infection prevention and control (IPC) within hospital settings. Methods: We conducted a prospective non-randomised trial of sequencing at 14 acute UK hospital trusts. Sites each had a 4-week baseline data-collection period, followed by intervention periods comprising 8 weeks of 'rapid' (<48h) and 4 weeks of 'longer-turnaround' (5-10 day) sequencing using a sequence reporting tool (SRT). Data were collected on all hospital onset COVID-19 infections (HOCIs; detected ≥48h from admission). The impact of the sequencing intervention on IPC knowledge and actions, and on incidence of probable/definite hospital-acquired infections (HAIs) was evaluated. Results: A total of 2170 HOCI cases were recorded from October 2020-April 2021, corresponding to a period of extreme strain on the health service, with sequence reports returned for 650/1320 (49.2%) during intervention phases. We did not detect a statistically significant change in weekly incidence of HAIs in longer-turnaround (incidence rate ratio 1.60, 95%CI 0.85-3.01; P=0.14) or rapid (0.85, 0.48-1.50; P=0.54) intervention phases compared to baseline phase. However, IPC practice was changed in 7.8% and 7.4% of all HOCI cases in rapid and longer-turnaround phases, respectively, and 17.2% and 11.6% of cases where the report was returned. In a 'per-protocol' sensitivity analysis there was an impact on IPC actions in 20.7% of HOCI cases when the SRT report was returned within 5 days. Capacity to respond effectively to insights from sequencing was breached in most sites by the volume of cases and limited resources. Conclusion: While we did not demonstrate a direct impact of sequencing on the incidence of nosocomial transmission, our results suggest that sequencing can inform IPC response to HOCIs, particularly when returned within 5 days. Funding: COG-UK is supported by funding from the Medical Research Council (MRC) part of UK Research & Innovation (UKRI), the National Institute of Health Research (NIHR) [grant code: MC_PC_19027], and Genome Research Limited, operating as the Wellcome Sanger Institute. Clinical trial number: ClinicalTrials.gov Identifier: NCT04405934

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Structural associations of symptomatic knee osteoarthritis

Objective Structural changes of osteoarthritis (OA) may occur in the absence of pain. In this study, we aimed to identify histopathologic features that are associated with symptomatic knee OA. Methods Medial tibial plateaus and synovium samples were obtained at the time of total knee replacement (TKR) surgery for OA (advanced OA group) or were obtained postmortem from subjects who had not sought medical attention for knee pain during the last year of life (non-OA control group). To identify features of OA, we compared the patients with advanced OA with the age-matched non-OA controls (n = 26 per group). To identify OA features associated with symptoms, we compared two additional groups of subjects who were matched for severity of chondropathy (n = 29 per group): patients undergoing TKR for symptomatic OA (symptomatic chondropathy group) and postmortem subjects with similar severity of chondropathy who were asymptomatic during the last year of life (asymptomatic chondropathy group). The histologic features of the samples were graded, and immunoreactivities for macrophages (CD68) and nerve growth factor (NGF) in the synovium were quantified. The cellular localization of synovial NGF was determined by double immunofluorescence analysis. Results Advanced OA cases displayed more severe changes in the synovium (synovitis, increased synovial NGF, and CD68-immunoreactive macrophages) and cartilage (loss of cartilage surface integrity, loss of proteoglycan, tidemark breaching, and alterations in chondrocyte morphology) than did the non-OA controls. Synovial NGF was localized predominantly to fibroblasts and to some macrophages. The symptomatic chondropathy group displayed greater levels of synovitis, synovial NGF, and loss of cartilage integrity, in addition to alterations in chondrocyte morphology, than did the asymptomatic chondropathy group (P < 0.05 for each comparison). Conclusion Synovitis, increased synovial NGF, alterations in chondrocyte morphology, and loss of cartilage integrity are features of knee OA that may be associated with symptoms