Origins, structures, and functions of circulating DNA in oncology.

While various clinical applications especially in oncology are now in progress such as diagnosis, prognosis, therapy monitoring, or patient follow-up, the determination of structural characteristics of cell-free circulating DNA (cirDNA) are still being researched. Nevertheless, some specific structures have been identified and cirDNA has been shown to be composed of many "kinds." This structural description goes hand-in-hand with the mechanisms of its origins such as apoptosis, necrosis, active release, phagocytosis, and exocytose. There are multiple structural forms of cirDNA depending upon the mechanism of release: particulate structures (exosomes, microparticles, apoptotic bodies) or macromolecular structures (nucleosomes, virtosomes/proteolipidonucleic acid complexes, DNA traps, links with serum proteins or to the cell-free membrane parts). In addition, cirDNA concerns both nuclear and/or mitochondrial DNA with both species exhibiting different structural characteristics that potentially reveal different forms of biological stability or diagnostic significance. This review focuses on the origins, structures and functional aspects that are paradoxically less well described in the literature while numerous reviews are directed to the clinical application of cirDNA. Differentiation of the various structures and better knowledge of the fate of cirDNA would considerably expand the diagnostic power of cirDNA analysis especially with regard to the patient follow-up enlarging the scope of personalized medicine. A better understanding of the subsequent fate of cirDNA would also help in deciphering its functional aspects such as their capacity for either genometastasis or their pro-inflammatory and immunological effects.

Clinical utility of circulating DNA analysis for rapid detection of actionable mutations to select metastatic colorectal patients for anti-EGFR treatment.

BACKGROUND: While tumor-tissue remains the 'gold standard' for genetic analysis in cancer patients, it is challenged with the advent of circulating cell-free tumor DNA (ctDNA) analysis from blood samples. Here, we broaden our previous study on the clinical validation of plasma DNA in metastatic colorectal cancer patients, by evaluating its clinical utility under standard management care. PATIENTS AND METHODS: Concordance and data turnaround-time of ctDNA when compared with tumor-tissue analysis were studied in a real-time blinded prospective multicenter clinical study (n = 140 metastatic colorectal patients). Results are presented according to STARD criteria and were discussed in regard with clinical outcomes of patients. RESULTS: Much more mutations were found by ctDNA analysis: 59%, 11.8% and 14.4% of the patients were found KRAS, NRAS and BRAF mutant by ctDNA analysis instead of 44%, 8.8% and 7.2% by tumor-tissue analysis. Median tumor-tissue data turnaround-time was 16 days while 2 days for ctDNA analysis. Discordant samples analysis revealed that use of biopsy, long delay between tumor-tissue and blood collection and resection of the tumor at time of blood draw, tumor site, or type of tissue analyzed seem to affect concordance. Altogether, the clinical data with respect to the anti-epidermal growth factor receptor response (RAS status) and the prognosis (BRAF status) of those discordant patients do not appear contradictory to the mutational status as determined by plasma analysis. Lastly, we present the first distribution profile of the RAS and BRAF hotspot mutations as determined by ctDNA analysis (n = 119), revealing a high proportion of patients with multiple mutations (45% of the population and up to 5 mutations) and only 24% of WT scored patients for both genes. Mutation profile as determined from ctDNA analysis with using various detection thresholds highlights the importance of the test sensitivity. CONCLUSION: Our study showed that ctDNA could replace tumor-tissue analysis, and also clinical utility of ctDNA analysis by considerably reducing data turnaround time.

The effect of dipyridamole on the pharmacokinetics of metformin: a randomized crossover study in healthy volunteers.

PURPOSE: Concomitant treatment with the glucose-lowering drug metformin and the platelet aggregation inhibitor dipyridamole often occurs in patients with type 2 diabetes mellitus who have suffered a cerebrovascular event. The gastrointestinal uptake of metformin is mediated by the human equilibrative nucleoside transporter 4 (ENT4), which is inhibited by dipyridamole in preclinical studies. We hypothesized that dipyridamole lowers the plasma exposure to metformin. METHODS: Eighteen healthy volunteers (mean age 23 years; 9 male) were randomized in an open-label crossover study. Subjects were allocated to treatment with metformin 500 mg twice daily in combination with dipyridamole slow-release 200 mg twice daily or to metformin alone for 4 days. After a washout period of 10 days, the volunteers were crossed over to the alternative treatment arm. Blood samples were collected during a 10-h period after intake of the last metformin dose. The primary endpoint was the area under the plasma concentration-time curve (AUC0-12h) and the maximum plasma metformin concentration (C max). RESULTS: In healthy subjects, dipyridamole did not significantly affect Cmax nor AUC0-12h of metformin under steady-state conditions. CONCLUSIONS: Previous in vitro studies report that dipyridamole inhibits the ENT4 transporter that mediates gastrointestinal uptake of metformin. In contrast, co-administration of dipyridamole at therapeutic dosages to healthy volunteers does not have a clinically relevant effect on metformin plasma steady-state exposure. This observation is reassuring for patients who are treated with this combination of drugs.

An Update on Inflammation in Atherosclerosis: How to Effectively Treat Residual Risk.

PURPOSE: This study reviewed the contribution of inflammation to atherosclerotic cardiovascular disease (ASCVD), which has gained widespread recognition in recent years. METHODS: This critical review evaluated how recent publications and ongoing clinical trials in atherosclerotic inflammation will affect clinical care. FINDINGS: Key trials, including CANTOS (Canakinumab Anti-Inflammatory Thrombosis Outcomes Study) with canakinumab (interleukin-1ß inhibition), and COLCOT (Colchicine Cardiovascular Outcomes Trial) and LoDoCo2 (Low Dose Colchicine 2) with colchicine, have shown that suppressing inflammation can improve outcomes in ASCVD. Cholesterol crystals play an important role in activating the NOD-, LRR-, and pyrin domain-containing protein 3 inflammasome and subsequent cytokine cascade. Inflammation contributes to significant residual risk after optimal lipid-lowering therapy. High-sensitivity C-reactive protein is a recognized biomarker of residual risk, and newer biomarkers such as the neutrophil to lymphocyte ratio may add additional information. The role of lipoprotein(a) as a proinflammatory agent or possible inflammatory biomarker is under investigation. The contribution of clonal hematopoiesis of indeterminate potential and trained immunity are in the early stages of investigation. Ongoing clinical trials of suppressing inflammation with NOD-, LRR-, and pyrin domain-containing protein 3 inflammasome inhibition (colchicine) and alternative approaches with downstream interleukin-6 ligand inhibition (ziltivekimab) will expand the evidence base for the use of anti-inflammatory agents in ASCVD. IMPLICATIONS: Based on current evidence and ongoing clinical trials, targeting inflammation alongside optimal lipid lowering is likely to be central to the future treatment of ASCVD. (Clin Ther. 2023;45:XXX-XXX) © 2023 Elsevier HS Journals, Inc.

Pharmaco-invasive therapy: Early implementation of statins and proprotein convertase subtilisin/kexin type 9 inhibitors after acute coronary syndrome.

Elevated LDL-cholesterol (LDL-C) plays a major role in atheroma formation and inflammation. Medical therapy to lower elevated LDL-C is the cornerstone for reducing the progression of atherosclerotic cardiovascular disease. Statin therapy, and more recently, other drugs such as proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, have proven efficacy in long-term lowering of LDL-C and therefore diminish cardiovascular risk. During an acute coronary syndrome (ACS), a systemic inflammatory response can destabilize other non-culprit atherosclerotic plaques. Patients with these vulnerable plaques are at high risk of experiencing recurrent cardiovascular events in the first few years post-ACS. Initiating intensive LDL-C lowering therapy in these patients with statins or PCSK9 inhibitors can be beneficial via several pathways. High-intensity statin therapy can reduce inflammation by directly lowering LDL-C, but also through its pleiotropic effects. PCSK9 inhibitors can directly lower LDL-C to recommended guideline thresholds, and could have additional effects on inflammation and plaque stability. We discuss the potential role of early implementation of statins combined with PCSK9 inhibitors to influence these cascades and to mediate the associated cardiovascular risk, over and above the well-known long-term beneficial effects of chronic LDL-C lowering.

Right atrial and ventricular strain detects subclinical changes in right ventricular function in precapillary pulmonary hypertension.

Right ventricular (RV) ejection fraction (EF) by cardiac magnetic resonance (CMR) correlates to outcome in precapillary pulmonary hypertension (pPH) patients, but is insensitive to early changes. Strain might provide incremental information. In this study, we compare right atrial (RA) and RV strain in pPH patients to healthy controls, and evaluate the prognostic value of strain in pPH. In this cross-sectional study, 45 pPH patients and 20 healthy controls underwent CMR, and feature-tracking derived RA and RV strain were evaluated. pPH patients had impaired RA reservoir and conduit strain, and RV longitudinal strain (LS), compared to healthy controls. In pPH patients with preserved RVEF (≥ 50%, n = 18), RA reservoir (35% ± 9 vs. 41% ± 6, p = 0.02) and conduit strain (16% ± 8 vs. 23% ± 5, p = 0.004), and RV-LS (-25% ± 4 vs. -31% ± 4, p < 0.001) remained impaired, compared to healthy controls. The association of strain with the primary endpoint (combination of all-cause death, lung transplantation, and heart failure hospitalization) was evaluated using a multivariable Cox regression model. RV-LS (HR 1.18, 95%-CI 1.04-1.34, p = 0.01) and RA strain (reservoir: HR 0.87, 95%-CI 0.80-0.94, p = 0.001; conduit: HR 0.85, 95%-CI 0.75-0.97, p = 0.02, booster: HR 0.81, 95%-CI 0.71-0.92, p = 0.001) were independent predictors of outcome, beyond clinical and imaging features. In conclusion, pPH patients have impaired RA strain and RV-LS, even when RVEF is preserved. In addition, RA strain and RV-LS were independent predictors of adverse prognosis. These results emphasize the incremental value of RA and RV strain analyses, to detect alterations in RV function, even before RVEF declines.

High dose ascorbic acid does not reverse central sympathetic overactivity in chronic heart failure.

WHAT IS KNOWN AND OBJECTIVE: The increased central sympathetic activity typically associated with chronic heart failure (CHF) is probably mediated by formation of reactive oxygen species (ROS) in the brain. Our objective was to undertake a trial to test our hypothesis that administration of the well-known antioxidant and ROS scavenger ascorbic acid, would reverse or reduce the sympathetic overactivity in CHF patients. METHODS: In a prospective, randomized, placebo-controlled, double-blind, cross-over trial, 11 CHF patients were treated with ascorbic acid 2 g/day or placebo for 3 days. At the end of each treatment period, sympathetic nervous system activity was measured by microneurography for direct muscle sympathetic nerve activity (MSNA) recording, analysis of heart rate variability (HRV) and measurement of plasma norepinephrine concentrations. RESULTS: During ascorbic acid administration, plasma vitamin C levels were higher than during placebo (74·9 ± 6·0 µmol/L vs. 54·8 ± 4·6 µmol/L, P = 0·03). Ascorbic acid had no effect on sympathetic activity: MSNA (ascorbic acid: 66·8 ± 3·3 vs. placebo 66·9 ± 3·2 bursts/100 beats, P = 0·98). In addition, HRV and plasma norepinephrine levels did not differ. WHAT IS NEW AND CONCLUSION: Short-term administration of the antioxidant ascorbic acid in CHF patients does not reverse the increased sympathetic activity as measured by microneurography, HRV and plasma norepinephrine levels. The use of higher oral dosages seems not feasible due to accompanying side effects.

Effect of dipyridamole on myocardial reperfusion injury: A double-blind randomized controlled trial in patients undergoing elective coronary artery bypass surgery.

Dipyridamole reduces reperfusion-injury in preclinical trials and may be beneficial in patients undergoing coronary angioplasty, but its effect on patients undergoing coronary artery bypass grafting (CABG) is unknown. We hypothesized that dipyridamole limits myocardial reperfusion-injury in patients undergoing CABG. The trial design was a double-blind trial randomizing between pretreatment with dipyridamole or placebo. In all, 94 patients undergoing elective on-pump CABG were recruited between February 2010 and June 2012. The primary endpoint was plasma high-sensitive (hs-) troponin-I at 6, 12, and 24 hours after reperfusion. Secondary endpoints were the occurrence of bleeding, arrhythmias, need for inotropic support, and intensive care unit length of stay. Finally, 79 patients (33 dipyridamole) were included in the per-protocol analysis. Dipyridamole did not significantly affect postoperative hs-troponin-I (change in plasma hs-troponin I -3% [95% confidence interval -23% to 36%]; P > 0.1). Secondary endpoints did not differ between groups. Dipyridamole prior to CABG does not significantly reduce postoperative hs-troponin release.

Expression pattern of the frizzled 7 gene during zebrafish embryonic development.

We have identified a novel frizzled gene in zebrafish, (Danio rerio): frizzled 7, highly related to mouse, chick and Xenopus fz7. No maternal expression was detected. Zygotic transcription starts at the end of gastrulation anteriorly in the presumptive neurectoderm and in the presomitic mesoderm. During somitogenesis expression is detected in developing central nervous system, including forebrain, midbrain, hindbrain and spinal cord, the lateral mesoderm and the anterior part of the forming somites. The strong sequence conservation of fz7 to the mouse, chick and Xenopus counterparts is also true for their expression pattern.

Ticagrelor Does Not Inhibit Adenosine Transport at Relevant Concentrations: A Randomized Cross-Over Study in Healthy Subjects In Vivo.

BACKGROUND AND PURPOSE: In patients with myocardial infarction, ticagrelor reduces cardiovascular and sepsis-related mortality, and can cause dyspnea. It is suggested that this is caused by adenosine receptor stimulation, because in preclinical studies, ticagrelor blocks the nucleoside transporter and increases cellular ATP release. We now investigated the effects of ticagrelor on the adenosine system in humans in vivo. EXPERIMENTAL APPROACH: In a double-blinded, placebo-controlled cross-over trial in 14 healthy subjects, we have tested whether ticagrelor (180 mg) affects adenosine- and dipyridamole-induced forearm vasodilation, as surrogates of nucleoside uptake inhibition and adenosine formation, respectively. Also, ex vivo uptake of adenosine and uridine in isolated red blood cells was measured. Primary endpoint was adenosine-induced vasodilation. KEY RESULTS: Ticagrelor did not affect adenosine- or dipyridamole-induced forearm vasodilation. Also, ex vivo uptake of adenosine and uridine in isolated red blood cells was not affected by ticagrelor. In vitro, ticagrelor dose-dependently inhibited nucleoside uptake, but only at supra-physiological concentrations. CONCLUSION AND IMPLICATIONS: In conclusion, at relevant plasma concentration, ticagrelor does not affect adenosine transport, nor adenosine formation in healthy subjects. Therefore, it is unlikely that this mechanism is a relevant pleiotropic effect of ticagrelor. TRIAL REGISTRATION: ClinicalTrials.gov NCT01996735.