Short-chain fatty acids induce tissue plasminogen activator in airway epithelial cells via GPR41&43

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous chronic inflammatory disease generally divided based on the presence or absence of nasal polyps (NPs). One of the features of NPs is excessive fibrin deposition, which is associated with down-regulation of tissue plasminogen activator (t-PA) in NPs. As t-PA is expressed in epithelial cells, and epithelium is readily accessible to topical therapies, identifying compounds that can mediate the induction of t-PA would be a potential new strategy for the treatment of NPs.

OBJECTIVE

The objective of this study was to determine whether short-chain fatty acids (SCFAs) can induce t-PA in airway epithelial cells via their known receptors GPR41 and GPR43.

METHODS

We performed immunohistochemistry (IHC) to determine whether receptors for SCFAs, known as G protein-coupled receptor 41/free fatty acid receptor 3 (GPR41/FFAR3) and GPR43/FFAR2, are expressed in nasal tissue. Primary normal human bronchial epithelial (NHBE) cells were stimulated with different concentrations of SCFAs to test induction of t-PA, which was analysed by expression of mRNA and protein. Mediation of responses by SCFA receptors was evaluated by specific receptor gene silencing with siRNA.

RESULTS

Immunohistochemistry study revealed that airway epithelial cells expressed GPR41 and GPR43. Acetic acid, propionic acid, butyric acid and valeric acid significantly induced t-PA expression from two- to tenfolds. The strongest inducer of t-PA from NHBE cells was propionic acid; cells stimulated with propionic acid released t-PA into the supernatant in its active form. Gene silencing of GPR41 and GPR43 revealed that induction of t-PA by SCFAs was dependent upon both GPR41 and GPR43.

CONCLUSIONS AND CLINICAL RELEVANCE

Short-chain fatty acids were shown to induce airway epithelial cell expression of t-PA via GPR41 and GPR43. Topical delivery of potent compounds that activate these receptors may have value by reducing fibrin deposition and shrinking nasal polyp growth.

Randomized Evaluation of the Effects of Anacetrapib through Lipid-modification (REVEAL)-A large-scale, randomized, placebo-controlled trial of the clinical effects of anacetrapib among people with established vascular disease: Trial design, recruitment, and baseline characteristics

Patients with prior vascular disease remain at high risk for cardiovascular events despite intensive statin-based treatment. Inhibition of cholesteryl ester transfer protein by anacetrapib reduces low-density lipoprotein (LDL) cholesterol by around 25% to 40% and more than doubles high-density lipoprotein (HDL) cholesterol. However, it is not known if these apparently favorable lipid changes translate into reductions in cardiovascular events.

METHODS

The REVEAL study is a randomized, double-blind, placebo-controlled clinical trial that is assessing the efficacy and safety of adding anacetrapib to effective LDL-lowering treatment with atorvastatin for an average of at least 4years among patients with preexisting atherosclerotic vascular disease. The primary assessment is an intention-to-treat comparison among all randomized participants of the effects of allocation to anacetrapib on major coronary events (defined as the occurrence of coronary death, myocardial infarction, or coronary revascularization).

RESULTS

Between August 2011 and October 2013, 30,449 individuals in Europe, North America, and China were randomized to receive anacetrapib 100mg daily or matching placebo. Mean (SD) age was 67 (8) years, 84% were male, 88% had a history of coronary heart disease, 22% had cerebrovascular disease, and 37% had diabetes mellitus. At the randomization visit (after at least 8weeks on a protocol-defined atorvastatin regimen), mean plasma LDL cholesterol was 61 (15) mg/dL and HDL cholesterol was 40 (10) mg/dL.

INTERPRETATION

The REVEAL trial will provide a robust evaluation of the clinical efficacy and safety of adding anacetrapib to an effective statin regimen. Results are anticipated in 2017.

Effect on non-vascular outcomes of lowering LDL cholesterol in patients with chronic kidney disease: results from the Study of Heart and Renal Protection

Background

Reducing LDL cholesterol (LDL-C) with statin-based therapy reduces the risk of major atherosclerotic events among patients with chronic kidney disease (CKD), with no evidence of an excess risk of cancer or death from any non-vascular cause. However, non-randomized data have suggested that statin therapy may have effects (both adverse and beneficial) on particular non-vascular conditions that do not cause death.

Methods

The Study of Heart and Renal Protection (SHARP) randomized patients with CKD to simvastatin 20 mg plus ezetimibe 10 mg (simvastatin/ezetimibe) daily versus matching placebo. Participants were followed up at least 6 monthly and all post-randomization serious adverse events (SAEs) were recorded. This supplementary analysis reports the effects of treatment on non-vascular SAEs, overall, by system of disease, by baseline characteristics, and by duration of follow-up.

Results

During a median of 4.9 years follow-up, similar numbers of participants in the two groups experienced at least one non-vascular SAE (3551 [76.4%] simvastatin/ezetimibe vs 3537 [76.6%] placebo; risk ratio [RR] 0.99, 95% confidence interval [CI] 0.95–1.04). There was no good evidence of any significant effect of simvastatin/ezetimibe on SAEs attributed to any particular nonvascular disease system (of 43 comparisons, only 3 yielded an uncorrected p value < 0.05, of which the smallest was p = 0.02). The relative risk of any nonvascular SAE did not vary significantly among particular prognostic subgroups or by duration of follow-up.

Conclusions

In the SHARP trial, allocation to simvastatin/ezetimibe combination therapy was not associated with any significant non-vascular hazard.

Trials registration

SHARP was retrospectively registered after the first participant was enrolled in 2003 at ISRCTN (ISRCTN54137607 on 31 January 2005: http://www.isrctn.com/ISRCTN54137607) and ClinicalTrials.gov (NCT00125593 on 29 July 2005: https://clinicaltrials.gov/ct2/show/NCT00125593).

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0545-2) contains supplementary material, which is available to authorized users.

Cost savings with a new screening algorithm for pulmonary arterial hypertension in systemic sclerosis

BACKGROUND

Screening for pulmonary arterial hypertension (PAH) in systemic sclerosis (SSc) is now standard care in this disease. The existing Australian Scleroderma Interest Group algorithm (ASIGSTANDARD ) is based on transthoracic echocardiography (TTE) and pulmonary function tests (PFT). Recently, ASIG has derived and validated a new screening algorithm (ASIGPROPOSED ) that incorporates N-terminal pro-B-type natriuretic peptide level together with PFT in order to decrease reliance on TTE, which has some limitations. Right heart catheterisation (RHC) remains the gold standard for the diagnosis of PAH in patients who screen 'positive'.

AIM

To compare the cost of PAH screening in SSc with ASIGSTANDARD and ASIGPROPOSED algorithms.

METHODS

We applied both ASIGSTANDARD and ASIGPROPOSED algorithms to 643 screen-naïve SSc patients from the Australian Scleroderma Cohort Study (ASCS), assuming a PAH prevalence of 10%. We compared the costs of screening, the number of TTE required and both the total number of RHC required and the number of RHC needed to diagnose one case of PAH, and costs, according to each algorithm. We then extrapolated the costs to the estimated total Australian SSc population.

RESULTS

In screen-naïve patients from the ASCS, ASIGPROPOSED resulted in 64% fewer TTE and 10% fewer RHC compared with ASIGSTANDARD , with $1936 (15%) saved for each case of PAH diagnosed. When the costs were extrapolated to the entire Australian SSc population, there was an estimated screening cost saving of $946 000 per annum with ASIGPROPOSED , with a cost saving of $851 400 in each subsequent year of screening.

CONCLUSIONS

ASIGPROPOSED substantially reduces the number of TTE and RHC required and results in substantial cost savings in SSc-PAH screening compared with ASIGSTANDARD .

Single-specificity anti-Ku antibodies in an international cohort of 2140 systemic sclerosis subjects: clinical associations

Autoantibodies directed against the Ku autoantigen are present in systemic sclerosis (SSc) and have been associated with myositis overlap and interstitial lung disease (ILD). However, there is a paucity of data on the clinical correlates of anti-Ku antibodies in the absence of other SSc-specific antibodies. The aim of this study was to assess the clinical correlates of single-specificity anti-Ku in SSc.An international (Canada, Australia, USA, Mexico) cohort of 2140 SSc subjects was formed, demographic and clinical variables were harmonized, and sera were tested for anti-Ku using a line immunoassay. Associations between single-specificity anti-Ku antibodies (i.e., in isolation of other SSc-specific antibodies) and outcomes of interest, including myositis, ILD, and survival, were investigated.Twenty-four (1.1%) subjects had antibodies against Ku, and 13 (0.6%) had single-specificity anti-Ku antibodies. Subjects with single-specificity anti-Ku antibodies were more likely to have ILD (58% vs 34%), and to have increased creatine kinase levels (>3× normal) at baseline (11% vs 1%) and during follow-up (10% vs 2%). No difference in survival was noted in subjects with and without single-specificity anti-Ku antibodies.This is the largest cohort to date focusing on the prevalence and disease characteristics of single-specificity anti-Ku antibodies in subjects with SSc. These results need to be interpreted with caution in light of the small sample. International collaboration is key to understanding the clinical correlates of uncommon serological profiles in SSc.

The patient impact of point-of-care vs. laboratory placement of Xpert(®) MTB/RIF

BACKGROUND

The Xpert(®) MTB/RIF assay can diagnose tuberculosis (TB) rapidly and with great accuracy. The effect of Xpert placement at point of care (POC) vs. at an off-site laboratory on patient management remains unknown.

DESIGN

At a primary care clinic in Johannesburg, South Africa, we compared TB diagnosis and treatment initiation among 1861 individuals evaluated for pulmonary TB using Xpert performed either at POC or offsite.

RESULTS

When Xpert was performed at POC, a higher proportion of Xpert-positive individuals started treatment (95% vs. 87%, P = 0.047) and time to treatment initiation was shorter (median 0 vs. 5 days, P < 0.001). In contrast, among Xpert-negative TB cases, a higher proportion (87% vs. 72%, P = 0.001) started treatment when the sample was sent to the laboratory, with a shorter time to treatment (median 9 vs. 13 days, P = 0.056). While the overall proportion of presumed TB patients starting treatment was independent of Xpert placement, the proportion started based on a bacteriologically confirmed diagnosis was higher when Xpert was performed at POC (73% vs. 58%, P = 0.006).

CONCLUSIONS

Placement of Xpert at POC resulted in more Xpert-positive patients receiving treatment, but did not increase the total number of presumed TB patients starting treatment. When samples were sent to a laboratory for Xpert testing, empiric decision making increased.

Interpretation of an Extended Autoantibody Profile in a Well-Characterized Australian Systemic Sclerosis (Scleroderma) Cohort Using Principal Components Analysis

OBJECTIVE

To determine the relationships between systemic sclerosis (SSc)-related autoantibodies, as well as their clinical associations, in a well-characterized Australian patient cohort.

METHODS

Serum from 505 Australian SSc patients were analyzed with a commercial line immunoassay (EuroLine; Euroimmun) for autoantibodies to centromere proteins CENP-A and CENP-B, RNA polymerase III (RNAP III; epitopes 11 and 155), the 90-kd nucleolar protein NOR-90, fibrillarin, Th/To, PM/Scl-75, PM/Scl-100, Ku, topoisomerase I (topo I), tripartite motif-containing protein 21/Ro 52, and platelet-derived growth factor receptor. Patient subgroups were identified by hierarchical clustering of the first 2 dimensions of a principal components analysis of quantitative autoantibody scores. Results were compared with detailed clinical data.

RESULTS

A total of 449 of the 505 patients were positive for at least 1 autoantibody by immunoblotting. Heatmap visualization of autoantibody scores, along with principal components analysis clustering, demonstrated strong, mutually exclusive relationships between CENP, RNAP III, and topo I. Five patient clusters were identified: CENP, RNAP III strong, RNAP III weak, topo I, and other. Clinical features associated with CENP, RNAP III, and topo I were consistent with previously published reports concerning limited cutaneous and diffuse cutaneous SSc. A novel finding was the statistical separation of RNAP III into 2 clusters. Patients in the RNAP III strong cluster had an increased risk of gastric antral vascular ectasia, but a lower risk of esophageal dysmotility. Patients in the other cluster were more likely to be male and to have a history of smoking and a history of malignancy, but were less likely to have telangiectasia, Raynaud's phenomenon, and joint contractures.

CONCLUSION

Five major autoantibody clusters with specific clinical and serologic associations were identified in Australian SSc patients. Subclassification and disease stratification using autoantibodies may have clinical utility, particularly in early disease.

The impact of Xpert(®) MTB/RIF in sparsely populated rural settings

BACKGROUND

The impact of implementing Xpert(®) MTB/RIF and the choice of instrument placement on patient care in sparsely populated areas with poor access to laboratory and radiology services have not yet been elucidated.

METHODS

Prospective evaluation of three diagnostic approaches in the Central Karoo, South Africa: smear microscopy as the initial diagnostic, with sputum processing at centralised laboratories, and Xpert as the initial diagnostic with instrument placement at facility level or centralised laboratory.

RESULTS

Of 1449 individuals, 196 were diagnosed with TB. The proportion positive on initial testing was respectively 8%, 20% and 8% during the smear microscopy, decentralised Xpert and centralised Xpert periods. The proportion of bacteriologically confirmed cases was respectively 88%, 99% and 91% during the smear microscopy, decentralised Xpert and centralised Xpert periods. The median time to treatment was respectively 11.5 (interquartile range [IQR] 6-24), 1 (IQR 0-2) and 6 days (IQR 2-9) during the smear microscopy, decentralised Xpert and centralised Xpert periods.

CONCLUSION

Introducing Xpert as the initial diagnostic in areas with poor access to TB diagnostics increased the proportion of cases with bacteriological confirmation and reduced time to treatment initiation; however, point-of-care placement may have resulted in fewer people being evaluated for TB.

Successes, challenges and lessons from a novel deployment of Xpert(®) MTB/RIF at a major South African public event [Short Communication]

In a mobile deployment of Xpert(®) MTB/RIF (Xpert) at the public event for 2012 South African World TB Day, Xpert testing was offered to tuberculosis (TB) symptomatic clients from gold mining and surrounding communities. Considerations before implementation included effective TB symptom screening; safe, effective sputum collection; uninterrupted electricity supply; stringent instrument verification and provision of on-site results. Public event Xpert testing is feasible; however, the case-finding rate was very low (0.7%). We recommend exploring enhanced symptom screening algorithms to improve pre-test probability, cost-effectiveness analysis, exploring alternate electrical fail-safes and on-site data connectivity and improving management of client expectations.

The association of antiphospholipid antibodies with cardiopulmonary manifestations of systemic sclerosis

OBJECTIVES

To determine the prevalence and correlates of antiphospholipid antibodies (APLA) in systemic sclerosis (SSc).

METHODS

Nine hundred and forty SSc patients were tested for APLA using an ELISA assay at recruitment. Clinical manifestations were defined as present, if ever present from SSc diagnosis. Logistic regression analysis was used to determine the associations of APLA.

RESULTS

One or more types of APLA were present in 226 (24.0%) patients. Anticardiolipin (ACA) IgG (ACA-IgG) antibodies were associated with right heart catheter-diagnosed pulmonary arterial hypertension (PAH), with higher titres corresponding with a higher likelihood of PAH (moderate titre (20-39 U/ml) ACA-IgG odds ratio [OR] 1.70, 95% CI: 1.01-2.93, p=0.047; high titre (>40 U/ml) ACA-IgG OR 4.60, 95% CI:1.02-20.8, p=0.047). Both ACA-IgM (OR 2.04, 95% CI: 1.4-3.0, p<0.0001) and ACA-IgG (OR 1.84, 95% CI: 1.2-2.8, p=0.005) were associated with interstitial lung disease (ILD). Increasing ACA-IgM and IgG titres were associated with increased likelihood of ILD. ACA-IgG was a marker of coexistent pulmonary hypertension and ILD (ILD-PH) (OR 2.10, 95% CI: 1.1-4.2, p=0.036). We also found an association between ACA-IgG and digital ulcers (OR 1.76, 95% CI: 1.16-2.67, p=0.008) and ACA-IgM and Raynaud's phenomenon (OR 2.39, 95% CI: 1.08-5.27, p=0.031). There was no association between APLA and SSc disease subtype, peak skin score, presence of other autoantibodies, mortality or other disease manifestations.

CONCLUSIONS

The association of APLA with PAH, ILD, ILD-PH, Raynaud's phenomenon and digital ulcers suggests that endothelial abnormalities and small vessel thrombosis may be important in the pathogenesis of these disease features.

Should patients with systemic sclerosis-related pulmonary arterial hypertension be anticoagulated?

Pulmonary arterial hypertension (PAH) is a major cause of mortality in scleroderma and despite 'advanced' therapies confers a median survival of less than 5 years. Anticoagulation in systemic sclerosis-related PAH (SSc-PAH) is currently one of the most contentious issues in the management of patients with connective tissue disease. While some studies have shown a survival benefit with warfarin therapy in this disease, others have not. Accordingly, a state of clinical equipoise exists in relation to anticoagulation in SSc-PAH. With an over fivefold reduction in mortality demonstrated in some observational studies, the issue of anticoagulation in SSc-PAH demands resolution through a well-designed randomised controlled trial.

Evaluation of an affordable HIV-1 virological failure assay and antiretroviral drug resistance genotyping protocol

HIV-1 RNA viral load is the preferred tool to monitor virological failure during antiretroviral therapy (ART) exposure. Timely detection of virological failure can reduce the prevalence and complexity of HIV-1 drug resistance. This field evaluation further characterizes a two-step approach to identify virological failure, as a measure of ART adherence, and detect HIVDR mutations in the reverse transcriptase (RT) gene of HIV-1. Two hundred and forty-eight (248) samples were tested; 225 from South African HIV-1 participants enrolled in the PharmAccess African Studies to Evaluate Resistance (PASER) cohort, forty of which had paired dried blood spot (DBS) samples and 23 HIV-1 negative samples. A newly developed virological failure assay (ARTA-VFA) was used on all samples, and those with a viral load >5000 RNA copies/ml were genotyped with a shortened RT protocol to detect HIVDR (ARTA-HIVDR(ultralight)). The ARTA-VFA showed good precision and linearity as compared to a commercial reference assay (NucliSENS EasyQ v1.2, Roche) with an R(2) of 0.99. Accuracy studies illustrated standard deviations of <1 log RNA copies/ml for plasma and DBS ARTA-VFA results compared to the reference method. The ARTA-VFA's intended use was to deliver qualitative results either < or >5000 RNA copies/ml. No significant differences in the proportion of results < or > either the 5000 RNA copies/ml or 1000 RNA copies/ml cut-off were noted for plasma indicating either cut-off to be useful. Significant differences were noted in these proportions when DBS were used (P=0.0002), where a 5000 RNA copies/ml cut-off was deemed more appropriate. The sensitivity and specificity of the ARTA-VFA with plasma were 95% and 93% and 91% and 95% for DBS using a 5000 RNA copies/ml cut-off. The ARTA HIVDR(ultralight) assay was reliable for plasma and DBS samples with a viral load >5000 RNA copies/ml, with amplification and sequencing success rates of 91% and 92% respectively for plasma, and 95% and 80% respectively for DBS. HIVDR profiles for plasma and DBS were 100% concordant with the reference assay. This study evaluated a previously described combination of two assays potentially useful in assessing HIV-1 virological failure and resistance, showing good concordance with reference assays. These assays are simple to perform and are affordable, viable options to detect virological failures in certain resource limited settings. The assays' compatibility with DBS sampling extends the access of HIV-1 virological monitoring to more remote settings.