Predicted expression of genes involved in the thiopurine metabolic pathway and azathioprine discontinuation due to myelotoxicity

TPMT and NUDT15 variants explain less than 25% of azathioprine‐associated myelotoxicity. There are 25 additional genes in the thiopurine pathway that could also contribute to azathioprine myelotoxicity. We hypothesized that among TPMT and NUDT15 normal metabolizers, a score combining the genetically predicted expression of other proteins in the thiopurine pathway would be associated with a higher risk for azathioprine discontinuation due to myelotoxicity. We conducted a retrospective cohort study of new users of azathioprine who were normal TPMT and NUDT15 metabolizers. In 1201 White patients receiving azathioprine for an inflammatory disease, we used relaxed Least Absolute Shrinkage and Selection Operator (LASSO) regression to select genes that built a score for discontinuing azathioprine due to myelotoxicity. The score incorporated the predicted expression of AOX1 and NME1. Patients in the highest score tertile had a higher risk of discontinuing azathioprine compared to those in the lowest tertile (hazard ratio [HR] = 2.15, 95% confidence interval [CI] = 1.11–4.19, p = 0.024). Results remained significant after adjusting for a propensity score, including sex, tertile of calendar year at initial dose, initial dose, age at baseline, indication, prior TPMT testing, and the first 10 principal components of the genetic data (HR = 2.11, 95% CI = 1.08–4.13, p = 0.030). We validated the results in a cohort (N = 517 non‐White patients and those receiving azathioprine to prevent transplant rejection) that included all other patients receiving azathioprine (HR = 2.00, (95% CI = 1.09–3.65, p = 0.024). In conclusion, among patients who were TPMT and NUDT15 normal metabolizers, a score combining the predicted expression of AOX1 and NME1 was associated with an increased risk for discontinuing azathioprine due to myelotoxicity.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Azathioprine is an immunosuppressant that causes myelotoxicity in some people. Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines provide azathioprine dosing recommendations based on TPMT and NUDT15 genotype; however, these genotypes explain only 25% of azathioprine‐induced myelotoxicity.

• WHAT QUESTION DID THIS STUDY ADDRESS?

The aim of this study was to determine if a risk score composed of the genetically predicted expression of genes that encode proteins in the thiopurine pathway within the liver tissue would be associated with azathioprine discontinuation attributed to myelotoxicity.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

This study showed that a risk score composed of genetically predicted risk expression of AOX1 and NME1 is associated with azathioprine discontinuation due to myelotoxicity.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Having a risk score for discontinuation composed of the genetically predicted expression of NME1 and AOX1 could help discriminate patients at high risk of discontinuing azathioprine due to hematologic side effects in people who are normal TPMT and NUDT15 metabolizers.     

Role of different nocturnal monitorings in the evaluation of CPAP titration by autoCPAP devices

The aim of the study was to assess how the analysis of different signals recorded during application of automatic continuous positive airway pressure (autoCPAP) devices improves the evaluation of pressure titration in patients with obstructive sleep apnea syndrome (OSAS) naive to treatment. Seventy-two patients underwent nocturnal polysomnography during autoCPAP (Autoset T, ResMed, Sydney, Australia) application. Progressively more complex combinations of signals were analysed in consecutive steps. According to the analysis of oxyhemoglobin saturation (SaO(2)) alone, a fixed CPAP level suitable for treatment could not be identified in 3 subjects. When analysis of posture was added, titration was considered unsatisfactory in 1 more subject, due to a short time spent supine. Further, addition of flow and respiratory movements led to consider titration unsatisfactory in 1 more subject. Analysis of all polysomnographic signals demonstrated a not fully reliable titration in 9 subjects: 1 with short sleep duration, 2 without REM sleep, 4 with a short sleep time spent supine, and 3 subjects (already identified by SaO(2)) with insufficient correction of respiratory disorders even when a relatively high CPAP was administered. Mask leaks did not hamper titration. CPAP titration by automatic devices alone results in imperfect titration in >10% subjects naive to ventilatory treatment. Only polysomnographic recording ensures titration reliability in all patients. Further research is needed to identify simple and economic methods to reliably start the CPAP treatment.     

Anti-ganglioside antibody-induced tumor cell death by loss of membrane integrity

Gangliosides have been involved in multiple cellular processes such as growth, differentiation and adhesion, and more recently as regulators of cell death signaling pathways. Some of these molecules can be considered as tumor-associated antigens, in particular, N-glycolyl sialic acid-containing gangliosides, which are promising candidates for cancer-targeted therapy because of their low expression in normal human tissues. In this study, we provided the molecular and cellular characterization of a novel cell death mechanism induced by the anti-NGcGM3 14F7 monoclonal antibody (mAb) in L1210 murine tumor cell line but not in mouse normal cells (B and CD4(+) T lymphocytes) that expressed the antigen. Impairment of ganglioside synthesis in tumor cells abrogated the 14F7 mAb cytotoxic effect; however, exogenous reincorporation of the ganglioside did not restore tumor cell sensitivity to 14F7 mAb-induced cytotoxicity. 14F7 F(ab')(2) but not Fab fragments retained the cytotoxic capacity of the whole mAb. By contrary, other mAb, which recognizes N-glycolylated gangliosides, did not show any cytotoxic effect. These mAbs showed quite different capacities to bind NGcGM3-positive cell lines measured by binding inhibition experiments. Interestingly, this complement-independent cell death mechanism did not resemble apoptosis, because no DNA fragmentation, caspase activation, or Fas mediation were observed. However, NGcGM3 ganglioside-mediated 14F7 mAb-induced cell death was accompanied by cellular swelling, membrane lesion formation, and cytoskeleton activation, suggesting an oncosis-like phenomenon. This novel mechanism of cell death lets us to support further therapeutic approaches using NGcGM3 as a molecular target for antibody-based cancer immunotherapy.     

Clinical predictors of remission and low disease activity in Latin American early rheumatoid arthritis: data from the GLADAR cohort

Objectives

To identify baseline predictors of remission and low disease activity (LDA) in early rheumatoid arthritis (RA) from the GLADAR (Grupo Latino Americano De estudio de la Artritis Reumatoide) cohort.

Methods

Patients with 1- and 2-year follow-up visits were included. Remission and LDA were defined by DAS28-ESR (< 2.6 and ≤ 3.2, respectively). Baseline predictors examined were gender, ethnicity, age at diagnosis, socioeconomic status, symptoms’ duration, DMARDs, RF, thrombocytosis, anemia, morning stiffness, DAS28-ESR (and its components), HAQ-DI, DMARDs and corticosteroid use, and Sharp-VDH score. Multivariable binary logistic regression models (excluding DAS28-ESR components to avoid over adjustment) were derived using a backward selection method (α-level set at 0.05).

Results

Four hundred ninety-eight patients were included. Remission and LDA/remission were met by 19.3% and 32.5% at the 1-year visit, respectively. For the 280 patients followed for 2 years, these outcomes were met by 24.3% and 38.9%, respectively. Predictors of remission at 1 year were a lower DAS28-ESR (OR 1.17; CI 1.07–1.27; p = 0.001) and HAQ-DI (OR 1.48; CI 1.04–2.10; p = 0.028). At 2 years, only DAS28-ESR (OR 1.40; CI 1.17–1.6; p < 0.001) was a predictor. Predictors of LDA/remission at 1 year were DAS28-ESR (OR 1.42; CI 1.26–1.61; p < 0.001), non-use of corticosteroid (OR 1.74; CI 1.11–2.44; p = 0.008), and male gender (OR 1.77; CI 1.2–2.63; p = 0.036). A lower baseline DAS28-ESR (OR 1.45; CI 1.23–1.70; p < 0.001) was the only predictor of LDA/remission at 2 years.

Conclusions

A lower disease activity consistently predicted remission and LDA/remission at 1 and 2 years of follow-up in early RA patients from the GLADAR cohort.

Ischemia induced by coronary steal through a patent mammary artery side branch: A role for embolization

Non-occlusion of the internal mammary artery side branches may cause ischemia due to flow diversion after coronary artery bypass grafting.The authors present the case of a 67-year-old man with recurrent angina after undergoing myocardial revascularization with a left internal mammary artery to left anterior descending bypass. He presented with impaired anterior wall myocardial perfusion in the setting of a patent left internal mammary artery side branch. Effective percutaneous treatment was carried out through coil embolization, with improved flow and clinical symptoms, confirmed through ischemia testing.Coronary steal through a patent mammary artery side branch is a controversial phenomenon and this type of intervention should be considered only in carefully selected patients.     

Caracterização do perfil lipídico nos utentes dos cuidados de saúde primários em Portugal

AimTo characterize the distribution of total cholesterol (TC), LDL cholesterol (LDL-C), HDL cholesterol (HDL-C) and triglycerides in primary health care users.MethodsWe performed a cross-sectional study in a primary care setting, involving 719 general practitioners based on stratified distribution proportional to the population density of each region of Portugal.The first two adult patients scheduled for an appointment on a given day were invited to participate. A questionnaire was applied to assess sociodemographic, clinical and laboratory data including lipid profile.ResultsThe study included 16 856 individuals (mean age 58.1±15.1 years; 61.6% women). Data on TC, LDL-C, HDL-C and triglycerides were available for 95.9% (n=16 159), 59.1% (n=9956), 95.4% (n=16 074) and 97.9% (n=16 494) of the population, respectively. Hypercholesterolemia (TC ≥200 mg/dl) was detected in 47%, and 38.4% had high levels of LDL-C (≥130 mg/dl). Hypertriglyceridemia (≥200 mg/dl) and low HDL-C (<40 mg/dl) were less prevalent, affecting roughly 13% of the population. Dyslipidemia was more common in middle-aged men and in post-menopausal women. Of the population aged over 40, 54.1% met eligibility criteria for lipid-lowering therapy and 44.7% were medicated with statins, but only 16.0% of these had TC ≤175 mg/dl.ConclusionsDyslipidemia is highly prevalent in primary health care users in Portugal. It is particularly common in middle-aged men and post-menopausal women, who should be considered target groups for preventive public health measures.