Proteogenomic Data Integration Reveals CXCL10 as a Potentially Downstream Causal Mediator for IL-6 Signaling on Atherosclerosis.

BACKGROUND: Genetic and experimental studies support a causal involvement of IL-6 (interleukin-6) signaling in atheroprogression. Although trials targeting IL-6 signaling are underway, any benefits must be balanced against an impaired host immune response. Dissecting the mechanisms that mediate the effects of IL-6 signaling on atherosclerosis could offer insights about novel drug targets with more specific effects. METHODS: Leveraging data from 522 681 individuals, we constructed a genetic instrument of 26 variants in the gene encoding the IL-6R (IL-6 receptor) that proxied for pharmacological IL-6R inhibition. Using Mendelian randomization, we assessed its effects on 3281 plasma proteins quantified with an aptamer-based assay in the INTERVAL cohort (n=3301). Using mediation Mendelian randomization, we explored proteomic mediators of the effects of genetically proxied IL-6 signaling on coronary artery disease, large artery atherosclerotic stroke, and peripheral artery disease. For significant mediators, we tested associations of their circulating levels with incident cardiovascular events in a population-based study (n=1704) and explored the histological, transcriptomic, and cellular phenotypes correlated with their expression levels in samples from human atherosclerotic lesions. RESULTS: We found significant effects of genetically proxied IL-6 signaling on 70 circulating proteins involved in cytokine production/regulation and immune cell recruitment/differentiation, which correlated with the proteomic effects of pharmacological IL-6R inhibition in a clinical trial. Among the 70 significant proteins, genetically proxied circulating levels of CXCL10 (C-X-C motif chemokine ligand 10) were associated with risk of coronary artery disease, large artery atherosclerotic stroke, and peripheral artery disease, with up to 67% of the effects of genetically downregulated IL-6 signaling on these end points mediated by decreases in CXCL10. Higher midlife circulating CXCL10 levels were associated with a larger number of cardiovascular events over 20 years, whereas higher CXCL10 expression in human atherosclerotic lesions correlated with a larger lipid core and a transcriptomic profile reflecting immune cell infiltration, adaptive immune system activation, and cytokine signaling. CONCLUSIONS: Integrating multiomics data, we found a proteomic signature of IL-6 signaling activation and mediators of its effects on cardiovascular disease. Our analyses suggest the interferon-γ-inducible chemokine CXCL10 to be a potentially causal mediator for atherosclerosis in 3 vascular compartments and, as such, could serve as a promising drug target for atheroprotection.

Revisiting specific force loss in human permeabilized single skeletal muscle fibers obtained from older individuals.

Specific force (SF) has been shown to be reduced in some but not all studies of human aging using chemically skinned single muscle fibers. This may be due, in part, not only to the health status/physical activity levels of different older cohorts, but also from methodological differences in studying skinned fibers. The aim of the present study was to compare SF in fibers from older hip fracture patients (HFP), healthy master cyclists (MC), and healthy nontrained young adults (YA) using two different activating solutions. Quadriceps muscle samples and 316 fibers were obtained from HFPs (74.6 ± 4 years, n = 5), MCs (74.8 ± 1, n = 5), and YA (25.5 ± 2, n = 6). Fibers were activated (pCa 4.5, 15°C) in solutions containing either 60 mM N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid pH buffer (TES) or 20 mM imidazole. SF was determined by normalizing force to fiber cross-sectional area (CSA) assuming either an elliptical or circular shape and to fiber myosin heavy chain content. Activation in TES resulted in significantly higher MHC-I SF in all groups and YA MHC-IIA fibers, irrespective of normalization method. Although there were no differences in SF between the participant groups, the ratio of SF between the TES and imidazole solutions was lower in HFPs compared with YAs (MHC-I P < 0.05; MHC-IIA P = 0.055). Activating solution composition, as opposed to donor characteristics, had a more notable effect on single fiber SF. However, this two-solution approach revealed an age-related difference in sensitivity in HFPs, which was not shown in MCs. This suggests further novel approaches may be required to probe age/activity-related differences in muscle contractile quality.NEW & NOTEWORTHY Whether specific force (SF) decreases with advancing age in human single skeletal muscle fibers is uncertain. Equivocal published findings may be due to the different physical activity levels of the elderly cohorts studied and/or different chemical solutions used to measure force. We compared single fiber SF between young adults, elderly cyclists, and hip fracture patients (HFP) using two solutions. The solution used significantly affected force and revealed a difference in sensitivity of HFP muscle fibers.

Proteogenomic integration reveals CXCL10 as a potentially downstream causal mediator for IL-6 signaling on atherosclerosis.

Background: Genetic and experimental studies support a causal involvement of interleukin-6 (IL-6) signaling in atheroprogression. While trials targeting IL-6 signaling are underway, any benefits must be balanced against an impaired host immune response. Dissecting the mechanisms that mediate the effects of IL-6 signaling on atherosclerosis could offer insights about novel drug targets with more specific effects. Methods: Leveraging data from 522,681 individuals, we constructed a genetic instrument of 26 variants in the gene encoding the IL-6 receptor (IL-6R) that proxied for pharmacological IL-6R inhibition. Using Mendelian randomization (MR), we assessed its effects on 3,281 plasma proteins quantified with an aptamer-based assay in the INTERVAL cohort (n=3,301). Using mediation MR, we explored proteomic mediators of the effects of genetically proxied IL-6 signaling on coronary artery disease (CAD), large artery atherosclerotic stroke (LAAS), and peripheral artery disease (PAD). For significant mediators, we tested associations of their circulating levels with incident cardiovascular events in a population-based study (n=1,704) and explored the histological, transcriptomic, and cellular phenotypes correlated with their expression levels in samples from human atherosclerotic lesions. Results: We found significant effects of genetically proxied IL-6 signaling on 70 circulating proteins involved in cytokine production/regulation and immune cell recruitment/differentiation, which correlated with the proteomic effects of pharmacological IL-6R inhibition in a clinical trial. Among the 70 significant proteins, genetically proxied circulating levels of CXCL10 were associated with risk of CAD, LAAS, and PAD with up to 67% of the effects of genetically downregulated IL-6 signaling on these endpoints mediated by decreases in CXCL10. Higher midlife circulating CXCL10 levels were associated with a larger number of cardiovascular events over 20 years, whereas higher CXCL10 expression in human atherosclerotic lesions correlated with a larger lipid core and a transcriptomic profile reflecting immune cell infiltration, adaptive immune system activation, and cytokine signaling. Conclusions: Integrating multiomics data, we found a proteomic signature of IL-6 signaling activation and mediators of its effects on cardiovascular disease. Our analyses suggest the interferon-γ-inducible chemokine CXCL10 to be a potentially causal mediator for atherosclerosis in three vascular compartments and as such could serve as a promising drug target for atheroprotection.

Digital technology and patient and public involvement (PPI) in routine care and clinical research-A pilot study.

BACKGROUND: Patient and public involvement (PPI) has growing impact on the design of clinical care and research studies. There remains underreporting of formal PPI events including views related to using digital tools. This study aimed to assess the feasibility of hosting a hybrid PPI event to gather views on the use of digital tools in clinical care and research. METHODS: A PPI focus day was held following local procedures and published recommendations related to advertisement, communication and delivery. Two exemplar projects were used as the basis for discussions and qualitative and quantitative data was collected. RESULTS: 32 individuals expressed interest in the PPI day and 9 were selected to attend. 3 participated in person and 6 via an online video-calling platform. Selected written and verbal feedback was collected on two digitally themed projects and on the event itself. The overall quality and interactivity for the event was rated as 4/5 for those who attended in person and 4.5/5 and 4.8/5 respectively, for those who attended remotely. CONCLUSIONS: A hybrid PPI event is feasible and offers a flexible format to capture the views of patients. The overall enthusiasm for digital tools amongst patients in routine care and clinical research is high, though further work and standardised, systematic reporting of PPI events is required.

Selective Interleukin-6 Trans-Signaling Blockade Is More Effective Than Panantagonism in Reperfused Myocardial Infarction.

Interleukin (IL)-6 is an emerging therapeutic target in myocardial infarction (MI). IL-6 has 2 distinct signaling pathways: trans-signaling, which mediates inflammation, and classic signaling, which also has anti-inflammatory effects. The novel recombinant fusion protein sgp130Fc achieves exclusive trans-signaling blockade, whereas anti-IL-6 antibodies (Abs) result in panantagonism. In a rat model of reperfused MI, sgp130Fc, but not anti-IL-6-Ab, attenuated neutrophil and macrophage infiltration into the myocardium, reduced infarct size, and preserved cardiac function 28 days after MI. These data demonstrate the efficacy of exclusive IL-6 trans-signaling blockade and support further investigation of sgp130Fc as a potential novel therapy in MI.

Aortic thrombosis in COVID-19.

BACKGROUND: Venous thrombo-embolism is now well-recognised as a common complication of severe COVID-19 disease. Arterial thrombosis has been less well recognised, although it is increasingly reported, mostly in the context of myocardial infarction and stroke. CASE REPORT: A 63-year-old man developed a pale, cold foot with an absent dorsalis pedis pulse 7 days into his admission with COVID-19. A CT angiogram demonstrated a large thrombus in the lower thoracic aorta, which had not been present on CT pulmonary angiogram the preceding week, along with occlusion of both popliteal arteries. He was managed with therapeutic dose of low molecular weight heparin (LMWH) for 6 weeks. RESULTS: This case adds to the growing list of potential sites and consequences of thrombosis in COVID-19. CONCLUSION: This case underscores the urgent need for pathophysiological studies and clinical trials to target treatments and guidelines for thromboprophylaxis in COVID-19.

Beyond dexamethasone, emerging immuno-thrombotic therapies for COVID-19.

Host immunity is required to clear SARS-CoV-2, and inability to clear the virus because of host or pathogen factors renders those infected at risk of poor outcomes. Estimates of those who are able to clear the virus with asymptomatic or paucisymptomatic COVID-19 remain unclear, and dependent on widespread testing. However, evidence is emerging that in severe cases, pathological mechanisms of hyperinflammation and coagulopathy ensue, the former supported by results from the RECOVERY trial demonstrating a reduction in mortality with dexamethasone in advanced COVID-19. It remains unclear whether these pathogenic pathways are secondary to a failure to clear the virus because of maladaptive immune responses or if these are sequential COVID-19 defining illnesses. Understanding the pathophysiological mechanisms underpinning these cascades is essential to formulating rationale therapeutic approaches beyond the use of dexamethasone. Here, we review the pathophysiology thought to underlie COVID-19 with clinical correlates and the current therapeutic approaches being investigated.

The impact of mental health disorders on outcomes following hip arthroscopy for femoroacetabular impingement syndrome: a systematic review.

Hip arthroscopy for femoroacetabular impingement syndrome (FAI) has been shown to be beneficial in the short- to medium-term though outcomes vary between individuals. Multiple factors have been suggested to affect outcomes including pre-operative mental health disorders. We undertook a systematic review to assess the evidence relating to the effect of pre-existing mental health disorders on the outcomes following hip arthroscopy for FAI. Following PRISMA guidelines, a multi-database search was undertaken using three key concepts: 'mental health', 'FAI' and 'hip arthroscopy'. Results were screened and data extracted from relevant studies. A total of six studies met the inclusion criteria including 2248 hips, all published between 2017 and 2019. All studies were of evidence level III or IV with reasonable methodological quality. One study demonstrated pre-operative depression to be related to altered pain reduction in the short-term following surgery. Three studies reported inferior outcomes in the medium-term (1-2 years) in those with worse mental health. One study demonstrated an increased risk of persistent pain 2 years following surgery and one a reduced chance of returning to active military service following surgery in those with worse mental health. Despite inferior outcomes individuals with mental health disorders did still benefit from surgery in general. In conclusion, the presence of pre-existing poor mental health is associated with inferior outcomes in the medium-term following arthroscopic surgery for FAI. Surgeons should consider screening patients for mental health disorders before surgery and counselling them appropriately as to the potential for less satisfactory surgical outcomes.

Novel Insights Into the Effects of Interleukin 6 Antagonism in Non-ST-Segment-Elevation Myocardial Infarction Employing the SOMAscan Proteomics Platform.

Background Interleukin 6 concentration is associated with myocardial injury, heart failure, and mortality after myocardial infarction. In the Norwegian tocilizumab non-ST-segment-elevation myocardial infarction trial, the first randomized trial of interleukin 6 blockade in myocardial infarction, concentration of both C-reactive protein and troponin T were reduced in the active treatment arm. In this follow-up study, an aptamer-based proteomic approach was employed to discover additional plasma proteins modulated by tocilizumab treatment to gain novel insights into the effects of this therapeutic approach. Methods and Results Plasma from percutaneous coronary intervention-treated patients, 24 in the active intervention and 24 in the placebo-control arm, drawn 48 hours postrandomization were randomly selected for analysis with the SOMAscan assay. Employing slow off-rate aptamers, the relative abundance of 1074 circulating proteins was measured. Proteins identified as being significantly different between groups were subsequently measured by enzyme immunoassay in the whole trial cohort (117 patients) at all time points (days 1-3 [7 time points] and 3 and 6 months). Five proteins identified by the SOMAscan assay, and subsequently confirmed by enzyme immunoassay, were significantly altered by tocilizumab administration. The acute-phase proteins lipopolysaccharide-binding protein, hepcidin, and insulin-like growth factor-binding protein 4 were all reduced during the hospitalization phase, as was the monocyte chemoattractant C-C motif chemokine ligand 23. Proteinase 3, released primarily from neutrophils, was significantly elevated. Conclusions Employing the SOMAscan aptamer-based proteomics platform, 5 proteins were newly identified that are modulated by interleukin 6 antagonism and may mediate the therapeutic effects of tocilizumab in non-ST-segment-elevation myocardial infarction.

Proximal Femoral Erosion: A Sequelae of Psuedoaneursym Formation Following Operative Fixation of an Intertrochanteric Neck of Femur Fracture.

A 72-year-old male sustained a left intertrochanteric neck of femur fracture following a fall. He underwent operative fixation with a dynamic hip screw and was discharged home. Fifteen months later, the patient presented again with ongoing left thigh pain and swelling. A pelvic radiograph showed scalloping of the medial proximal femoral cortex. Further investigation revealed a left profunda femoris artery pseudoaneurysm. Vascular injury during operative fixation of intratrochanteric fractures is a rare complication, which may be missed due to a delayed presentation. Treating physicians should be mindful of late presentations of vascular injury following the surgical fixation of proximal femoral fractures.

Variation in Interleukin 6 Receptor Gene Associates With Risk of Crohn's Disease and Ulcerative Colitis.

Interleukin 6 (IL6) is an inflammatory cytokine; signaling via its receptor (IL6R) is believed to contribute to development of inflammatory bowel diseases (IBD). The single nucleotide polymorphism rs2228145 in IL6R associates with increased levels of soluble IL6R (s-IL6R), as well as reduced IL6R signaling and risk of inflammatory disorders; its effects are similar to those of a therapeutic monoclonal antibody that blocks IL6R signaling. We used the effect of rs2228145 on s-IL6R level as an indirect marker to investigate whether reduced IL6R signaling associates with risk of ulcerative colitis (UC) or Crohn's disease (CD). In a genome-wide meta-analysis of 20,550 patients with CD, 17,647 patients with UC, and more than 40,000 individuals without IBD (controls), we found that rs2228145 (scaled to a 2-fold increase in s-IL6R) was associated with reduced risk of CD (odds ratio 0.876; 95% confidence interval 0.822-0.933; P = .00003) or UC (odds ratio 0.932; 95% confidence interval 0.875-0.996; P = .036). These findings indicate that therapeutics designed to block IL6R signaling might be effective in treatment of IBD.

Pro-resolving mediators promote resolution in a human skin model of UV-killed Escherichia coli-driven acute inflammation.

While the treatment of inflammatory disorders is generally based on inhibiting factors that drive onset of inflammation, these therapies can compromise healing (NSAIDs) or dampen immunity against infections (biologics). In search of new antiinflammatories, efforts have focused on harnessing endogenous pathways that drive resolution of inflammation for therapeutic gain. Identification of specialized pro-resolving mediators (SPMs) (lipoxins, resolvins, protectins, maresins) as effector molecules of resolution has shown promise in this regard. However, their action on inflammatory resolution in humans is unknown. Here, we demonstrate using a model of UV-killed Escherichia coli-triggered skin inflammation that SPMs are biosynthesized at the local site at the start of resolution, coinciding with the expression of receptors that transduce their actions. These include receptors for lipoxin A4 (ALX/FPR2), resolvin E1 (ChemR23), resolvin D2 (GPR18), and resolvin D1 (GPR32) that were differentially expressed on the endothelium and infiltrating leukocytes. Administering SPMs into the inflamed site 4 hours after bacterial injection caused a reduction in PMN numbers over the ensuing 6 hours, the phase of active resolution in this model. These results indicate that in humans, the appearance of SPMs and their receptors is associated with the beginning of inflammatory resolution and that their therapeutic supplementation enhanced the resolution response.

Effect of tranexamic acid use on blood loss and thromboembolic risk in hip fracture surgery: systematic review and meta-analysis.

INTRODUCTION: Intravenous tranexamic acid (IV TXA) is a recognised pharmaceutical intervention utilised to minimise blood loss and allogenic blood transfusion. However, the use of IV TXA in hip fracture surgery remains inconclusive. We conducted a meta-analysis to investigate the role of TXA in operative hip fracture management on operative and total blood loss, allogenic blood transfusion requirements and impact on venous thromboembolic (VTE) event incidence. METHODS: A systematic computerised literature search of PubMed, Medline, Embase, Ovid, The Cochrane Controlled Trials Register, Trip and Google was conducted. We reviewed the efficacy of IV TXA on perioperative blood loss, total blood loss, pre- and postoperative haemoglobin differences, duration of surgery, allogenic blood transfusion requirements and VTE events. RESULTS: 8 studies were eligible including 6 randomised control trials and 2 cohort studies. Patients receiving IV TXA had reduced mean total blood loss of 442.9 mls (95% CI, 426.5-459.3; p<0.00001), reduced operative blood loss of 88.5 mls (95% CI, 59.9-117.2; p<0.00001), a decrease in the need for allogenic blood transfusion (OR 0.37; 95% CI, 0.26-0.53; p<0.00001) and a reduction in pre- and postoperative haemoglobin difference (p = 0.013.) There was no significant increase in VTE risk (OR 1.59; 95% CI 0.67-3.75; p>0.29) or significant difference on duration of surgery seen with IV TXA usage (p>0.06). CONCLUSIONS: Our review demonstrated the efficacy of IV TXA in minimising perioperative, reducing total blood loss and lowering the necessity for allogenic blood transfusions with no significant increased risk in VTE events.

Experience and outcome data of the British non-arthroplasty hip registry.

INTRODUCTION: The non-arthroplasty hip registry (NAHR) is a United Kingdom national register that monitors the efficacy of hip preservation surgery. We aim to highlight early experiences of incorporating the NAHR into our practice at a tertiary centre. METHODS: Between December 2013 and February 2015, 381 patients were identified on the NAHR database that had undergone non-arthroplasty hip surgery. Patient-related outcome measures EuroQuol 5D-5L (EQ-5D) and the International Hip Outcome Tool 12 (iHOT-12) were recorded at baseline and 6 months. RESULTS: The 289 arthroscopic surgeries showed a statistical significant difference (p<0.05) in iHOT-12 for both males (45.21-65.07) and females (34.57 to 55.53), and in EQ-5D for both males (0.59-0.75) and females (0.56-0.65). The 92 open procedures showed a statistical significant difference (p<0.05) in both iHOT-12 (31.71-62.42) and EQ-5D (0.54-0.68). CONCLUSIONS: Overall our results from the NAHR indicate hip preservation surgery is effective at relieving pain and improving quality of life in the short term.

Potent Anti-Inflammatory and Pro-Resolving Effects of Anabasum in a Human Model of Self-Resolving Acute Inflammation.

Anabasum is a synthetic analog of Δ8 -tetrahydrocannabinol (THC)-11-oic acid that in preclinical models of experimental inflammation exerts potent anti-inflammatory actions with minimal central nervous system (CNS) cannabimimetic activity. Here we used a novel model of acute inflammation driven by i.d. UV-killed E. coli in healthy humans and found that anabasum (5 mg) exerted a potent anti-inflammatory effect equivalent to that of prednisolone in terms of inhibiting neutrophil infiltration, the hallmark of acute inflammation. These effects arose from the inhibition of the neutrophil chemoattractant LTB4 , while the inhibition of antiphagocytic prostanoids (PGE2 , TxB2 , and PGF2 α) resulted in enhanced clearance of inflammatory stimulus from the injected site. Anabasum at the higher dose of 20 mg possessed the additional properties of triggering the biosynthesis of specialized pro-resolving lipid mediators including LXA4 , LXB4 , RvD1, and RvD3. Collectively, we demonstrate for the first time a striking anti-inflammatory and pro-resolution effects of a synthetic analog of THC in healthy humans.

A Comparison of Human Neutrophils Acquired from Four Experimental Models of Inflammation.

Defects in neutrophil function have been implicated in a wide spectrum of clinical conditions. Several models are employed to study activated human neutrophils akin to those found at a site of inflammation. These include whole blood (WB) ex vivo stimulation with lipopolysaccharide (LPS) and in vivo techniques: cantharidin blister, skin windows and intra-dermal injection of UV-killed E.coli (UVKEc). Neutrophils obtained from these have never been compared. We compared the activation status of neutrophils from each technique in order to inform the optimal model for use in human studies. Healthy male volunteers were randomised to undergo one of the four techniques (n = 5/group). LPS: WB stimulated with 1ng/ml of LPS for 4 hours. Cantharidin: 12.5µl of 0.1% cantharidin elicited a single blister, aspirated at 24 hours. Skin windows: four 6mm mechanical-suction blisters created, de-roofed and an exudate-collection chamber placed over the windows for 4 hours before aspiration. UVKEc: 1.5 x 107 UVKEc injected intra-dermally. A single 10mm mechanical-suction blister formed and aspirated at 4 hours. Unstimulated WB used as the control. Flow cytometry was used to determine activation status using CD16, CD11b, CD54, CD62L and CD88. Functional status was assessed with a phagocytosis assay. The pattern of neutrophil activation was similar in all models. Neutrophil CD11b was elevated in all models, most markedly in UVKEc (p<0.0001), and CD54 was also elevated but only significant in the LPS model (p = 0.001). CD62L was significantly reduced in all 4 models (p<0.0001) and CD88 was also suppressed in all. There were no changes in CD16 in any model, neither was there any significant difference in the phagocytic capacity of the neutrophils. In summary, there are no significant differences in activation marker expression or phagocytic capacity in the neutrophils obtained from each technique. Therefore we believe whole blood stimulation is the best model in experimentally challenging inpatient populations.

Functional outcomes of total hip arthroplasty in patients aged 30 years or less: a systematic review and meta-analysis.

INTRODUCTION: Young adult hip surgery is a growing subspecialty. Increasingly total hip arthroplasty (THA) is offered to patients aged 30 or less suffering from end-stage hip arthropathy from a variety of congenital, developmental and acquired conditions. There is a paucity of evidence to advise such patients and surgeons alike on the functional outcomes of THA in this age group, as individual studies tend to include small cohorts. METHODS: A systematic review and meta-analysis was performed to assess whether THA in patients aged 30 years or less provides significant functional improvement. The primary outcome measure was change in Harris Hip Score. Secondary outcome measures were implant survivorship and the effect of fixation type and bearing surface. RESULTS: The results of 743 primary THA procedures were included. Weighted mean patient age was 22.7 years. Harris Hip Score improved by a weighted mean difference of 42.17 points out of 100 (95% confidence interval, 36.48-47.86 points, p<0.001) after THA at a weighted mean follow-up of 8.4 years. Pooled revision rate was 5.0% for the same time period. CONCLUSIONS: This is the largest review to date of THA in patients aged 30 or less. The results show significant functional improvement measured by Harris Hip Score. The revision rate of 5% at 8.4 years is comparable to the general THA population. This contrasts high revision rates reported in older reviews of the literature, suggesting adoption of improved techniques and implants in the more recent literature.