Daniele Mauro

Triggering of Suicidal Erythrocyte Death by Amphotericin B

Amphotericin B is widely used as antifungal drug. Side effects include anemia. A variety of drugs and diseases associated with anemia has recently been shown to trigger suicidal erythrocyte death or eryptosis, i.e. cell membrane scrambling and cell shrinkage. Eryptosis may be triggered by increased cytosolic Ca2+ activity and by lack of ATP. The present study explored whether amphotericin B stimulates eryptosis. Cell membrane scrambling was estimated from annexin V-binding to phosphatidylserine exposed at the cell surface, cell shrinkage from forward scatter in FACS analysis, cytosolic Ca2+ activity from Fluo3 fluorescence and the cytosolic ATP concentration from a luciferase-based assay. Exposure to amphotericin B (0.1 - 1 μg/ml) within 48 hours significantly increased annexin V-binding, decreased forward scatter, increased cytosolic Ca2+ activity and decreased cytosolic ATP content. In conclusion, amphotericin B stimulates suicidal cell death of erythrocytes, which may in turn contribute to the clearance of circulating erythrocytes and thus to anemia.

Inhibitory effect of thymol on suicidal erythrocyte death.

The antibacterial plant component thymol has antioxidant activity. Oxidative stress is known to activate Ca2+-permeable cation channels with subsequent Ca2+ entry, activation of Ca2+-sensitive K+ channels, cell shrinkage, cell membrane scrambling and phosphatidylserine exposure at the erythrocyte surface. Cell shrinkage and phosphatidylserine exposure are typical features of suicidal erythrocyte death or eryptosis. Eryptotic cells are cleared from circulating blood thus causing anemia and may adhere to the vascular wall thus interfering with the microcirculation. The present experiments explored whether thymol interacts with eryptosis. Annexin V-binding was utilized to determine phosphatidylserine exposure, forward scatter to detect alterations of cell volume and Fluo3 fluorescence to depict changes of the cytosolic Ca2+ activity. Oxidative stress (30 min. 0.3 mM tert-butylhydroperoxide), energy depletion (48 h glucose removal) and isotonic cell shrinkage (48 h replacement of extracellular Cl- with gluconate) significantly increased annexin V-binding and decreased the forward scatter, effects significantly blunted in the presence of thymol 2.5 - 20 μg/ml. Thymol is a potent inhibitor of suicidal erythrocyte death particularly following oxidative stress. In conclusion, thymol may be useful incounteracting anemia and impairment of microcirculation.

Abatacept Improves Whole-body Insulin Sensitivity in Rheumatoid Arthritis: An Observational Study

AbstractRheumatoid arthritis (RA) is characterized by increased insulin resistance, a well-known risk factor for diabetes and cardiovascular diseases. The aim of the present study was to evaluate the effect of abatacept on insulin sensitivity in RA patients with moderate to severe disease despite treatment with methotrexate.Fifteen RA patients were recruited for the present study. Patients were evaluated at time 0 and after 6 months of the treatment with i.v. abatacept at the dosage recommended for weight range. Evaluation included oral glucose tolerance test (OGTT) at both time points. Insulin sensitivity was estimated with insulin sensitivity index (ISI) by Matsuda, a measure of whole-body insulin sensitivity.ISI significantly increased after the treatment with abatacept from 3.7 ± 2.6 to 5.0 ± 3.2 (P = 0.003) with a mean difference of 1.23. Analysis of glucose and insulin values during OGTT revealed a reduction of both glucose (303.9 ± 73.4 mg/dL min versus 269.2 ± 69.5 mg/dL min, P = 0.009) and insulin (208.4 ± 119.7 mg/dL min versus 158.0 ± 95.3 mg/dL min, P = 0.01) area under the curves (AUCs). Accordingly also glycated hemoglobin significantly improved (5.5 ± 0.4% versus 5.3 ± 0.3%, P = 0.04). No significant differences were found for measures of &bgr;-cell function insulinogenic index (1.11 ± 1.19 versus 1.32 ± 0.82, P = 0.77) and oral disposition index (2.0 ± 5.4 versus 6.0 ± 6.0, P = 0.25).Treatment with abatacept seems to be able to improve whole-body insulin sensitivity in RA patients without affecting &bgr;-cell function.

Improvement in insulin resistance after short-term treatment with abatacept: case report and short review

Insulin resistance, a key feature of type 2 diabetes, is an independent risk factor for developing cardiovascular diseases (CVD), and represents the core of metabolic syndrome (MetS). Actually, an intriguing correlation between MetS and inflammation associated with rheumatoid arthritis (RA) is largely accepted but not yet completely clarified in detail. Recently, the therapeutic arsenal against RA has been enriched of abatacept, a fusion protein (CTLA4 immunoglobulin) designed to modulate the T cell co-stimulatory signal mediated through the CD28–CD80/86 pathway. Here, we report a case of dramatic improvement in insulin resistance, estimated with the surrogate measure HOMA-IR, after treatment with abatacept. Lastly, we shortly review the preclinical evidences supporting a possible role of T lymphocytes in rheumatoid arthritis-associated insulin resistance and how abatacept could improve glucose metabolism by suppressing adipose tissue infiltrating cells.

Anti-TNF-alpha agents and endothelial function in rheumatoid arthritis: a systematic review and meta-analysis

Rheumatoid arthritis (RA) has been associated with endothelial dysfunction, a pathophysiological feature of atherosclerosis. Our aim was to determine whether TNF-α blockade has a beneficial effect on endothelial function in RA. We performed a systematic review with meta-analysis to evaluate the effect of anti-TNF-α agents on endothelial function in RA patients. MedLine, Cochrane CENTRAL and SCOPUS were searched up to March 2016. Inclusion criteria were: 1) randomised controlled trial (RCT), quasi-RCT, before-after cohort study; 2) including RA patients; 3) treatment with anti-TNF-α medications; 4) evaluating the change from baseline in endothelial function. The search strategy retrieved 180 records, of which 20 studies were included in the systematic review. Pooled analysis using a random-effects model demonstrated a significant improvement in endothelial function following anti-TNF-α treatment (SDM 0.987, 95%CI [0.64–1.33], p < 0.0001). Generalisation of the results of the meta-analysis may be limited due to the presence of heterogeneity (I2 = 82.65%, p < 0.001) and evidence of possible publication bias. Meta-regression showed that endothelial function measurement technique was a significant contributor to heterogeneity. In conclusion, although limited by the methodological quality of the included studies, our meta-analysis suggests that anti-TNF-α treatment may improve endothelial function in RA patients.

Role of positron emission tomography for central nervous system involvement in systemic autoimmune diseases: status and perspectives.

In the last years, an increasing interest in molecular imaging has been raised by the extending potential of positron emission tomography [PET]. The role of PET imaging, originally confined to the oncology setting, is continuously extending thanks to the development of novel radiopharmaceutical and to the implementation of hybrid imaging techniques, where PET scans are combined with computed tomography [CT] or magnetic resonance imaging[MRI] in order to improve spatial resolution. Early preclinical studies suggested that 18F-FDG PET can detect neuroinflammation; new developing radiopharmaceuticals targeting more specifically inflammation-related molecules are moving in this direction. Neurological involvement is a distinct feature of various systemic autoimmune diseases, i.e. Systemic Lupus Erythematosus [SLE] or Behcets disease [BD]. Although MRI is largely considered the gold-standard imaging technique for the detection of Central Nervous System [CNS] involvement in these disorders. Several patients complain of neuropsychiatric symptoms [headache, epilepsy, anxiety or depression] in the absence of any significant MRI finding; in such patients the diagnosis relies mainly on clinical examination and often the role of the disease process versus iatrogenic or reactive forms is doubtful. The aim of this review is to explore the state-of-the-art for the role of PET imaging in CNS involvement in systemic rheumatic diseases. In addition, we explore the potential role of emerging radiopharmaceutical and their possible application in aiding the diagnosis of CNS involvement in systemic autoimmune diseases.

De novo mutations implicate novel genes in systemic lupus erythematosus

Abstract The omnigenic model of complex disease stipulates that the majority of the heritability will be explained by the effects of common variation on genes in the periphery of core disease pathways. Rare variant associations, expected to explain far less of the heritability, may be enriched in core disease genes and thus will be instrumental in the understanding of complex disease pathogenesis and their potential therapeutic targets. Here, using complementary whole-exome sequencing, high-density imputation, and in vitro cellular assays, we identify candidate core genes in the pathogenesis of systemic lupus erythematosus (SLE). Using extreme-phenotype sampling, we sequenced the exomes of 30 SLE parent-affected-offspring trios and identified 14 genes with missense de novo mutations (DNM), none of which are within the >80 SLE susceptibility loci implicated through genome-wide association studies. In a follow-up cohort of 10, 995 individuals of matched European ancestry, we imputed genotype data to the density of the combined UK10K-1000 genomes Phase III reference panel across the 14 candidate genes. Gene-level analyses indicate three functional candidates: DNMT3A, PRKCD, and C1QTNF4. We identify a burden of rare variants across PRKCD associated with SLE risk (P = 0.0028), and across DNMT3A associated with two severe disease prognosis sub-phenotypes (P = 0.0005 and P = 0.0033). We further characterise the TNF-dependent functions of the third candidate gene C1QTNF4 on NF-κB activation and apoptosis, which are inhibited by the p.His198Gln DNM. Our results identify three novel genes in SLE susceptibility and support extreme-phenotype sampling and DNM gene discovery to aid the search for core disease genes implicated through rare variation.

Complement C3 and fatty liver disease in rheumatoid arthritis patients: A cross-sectional study

Recent evidence suggested a potential role of complement fraction C3 as a biomarker of nonalcoholic fatty liver disease (NAFLD) in the general population. Aim of this study was to evaluate the performance of C3 for prediction of NAFLD in RA patients.

Endothelial Dysfunction in Systemic Lupus Erythematosus: Pathogenesis, Assessment and Therapeutic Opportunities

BACKGROUND Systemic Lupus Erythematosus (SLE) is characterised by increased mortality secondary to Cardiovascular Diseases (CVD). Despite being common in SLE, traditional cardiovascular risk factors cannot entirely justify such increase in CVD-associated mortality. The endothelium is a key regulator of the vascular homeostasis; lupus-associated persistent systemic inflammation may impair endothelium functionality, thus initiating a cascade of events that, in concert with traditional CVD-risk factors, leads to atherosclerosis development and progression. Numerous methods have been used for the in vivo assessment of the endothelial function; among all, Flow- Mediated Dilatation (FMD) has been widely validated in clinical trials. Quantification of the endothelial dysfunction by FMD has been confirmed to be an early predictor of CVD in multiple studies involving both non-CVD and CVD-population and it may therefore represent a likewise efficient biomarker of CVD in SLE. METHODS Research and online content related to endothelial function in SLE is reviewed in this article with special attention to the pathophysiology and therapeutic opportunities. RESULTS To date, the vast majority of the available data, albeit not all, shows that endotheliumdependent FMD values are lower in SLE patients compared to healthy subjects; further studies, however, will be required in order to confirm the usefulness of the endothelial dysfunction quantification as CVD-predictor in the specific clinical setting of lupus. Notably, FMD variations can also be a sensitive marker for assessing specific therapeutic strategies ability of improving endothelial function in SLE patients. CONCLUSION Endothelial function appears to be affected by SLE potentially contributing to the increased cardiovascular risk observed in SLE patients.

Serum Complement C3 and Type 2 Diabetes in Rheumatoid Arthritis: A Case-Control Study

BACKGROUND Recent evidence demonstrated a potential role of complement C3 as a candidate biomarker of cardiometabolic risk in the general population. OBJECTIVE Aim of the present study was to investigate the correlation between complement C3 levels and comorbid Type 2 Diabetes (T2DM) in Rheumatoid Arthritis (RA) patients. METHODS For the present study, 40 consecutive diabetic RA patients (RA/T2DM+ group) and 80 consecutive RA patients without diabetes (RA/T2DM- group) were recruited. RESULTS Patients in the RA/T2DM+ group were significantly older (p < 0.0001), had a longer RA duration (p < 0.0001) and higher disease activity (p = 0.006) compared to controls. Moreover, patients in the RA/T2DM+ group had significantly higher levels of ESR (p < 0.0001), CRP (p < 0.0001) and complement C3 (p < 0.0001). A logistic regression model was built to ascertain the effect of selected variables (age, RA duration, BMI, ESR, C3, lnCRP, corticosteroid use) on the likelihood that patients have T2DM. Longer RA duration, ESR and C3 were associated with an increased likelihood of being classified as T2DM. Finally, we built ROC curves to evaluate the predictivity of RA duration, complement C3 and the combination of both variables on the likelihood of being diagnosed with T2DM. The area under the ROC curve was 0.79 (p < 0.0001) for RA duration, 0.71 (p < 0.0001) for complement C3 and 0.89 (p < 0.0001) for the combination of both variables. CONCLUSION According to our data complement C3 levels can predict the presence of T2DM in RA patients.